Sample records for h3n2 swine influenza

  1. The PB2-K627E mutation attenuates H3N2 swine influenza virus in cultured cells and in mice.

    PubMed

    Gong, Xiao-Qian; Ruan, Bao-Yang; Liu, Xiao-Min; Zhang, Peng; Wang, Xiu-Hui; Wang, Qi; Shan, Tong-Ling; Tong, Wu; Zhou, Yan-Jun; Li, Guo-Xin; Zheng, Hao; Tong, Guang-Zhi; Yu, Hai

    2018-04-01

    PB2-627K is an important amino acid that determines the virulence of some influenza A viruses. However, it has not been experimentally investigated in the H3N2 swine influenza virus. To explore the potential role of PB2-K627E substitution in H3N2 swine influenza virus, the growth properties and pathogenicity between H3N2 swine influenza virus and its PB2-K627E mutant were compared. For the first time, our results showed that PB2-K627E mutation attenuates H3N2 swine influenza virus in mammalian cells and in mice, suggesting that PB2-627K is required for viral replication and pathogenicity of H3N2 swine influenza virus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Swine-origin influenza A (H3N2) virus infection in two children--Indiana and Pennsylvania, July-August 2011.

    PubMed

    2011-09-09

    Influenza A viruses are endemic in many animal species, including humans, swine, and wild birds, and sporadic cases of transmission of influenza A viruses between humans and animals do occur, including human infections with avian-origin influenza A viruses (i.e., H5N1 and H7N7) and swine-origin influenza A viruses (i.e., H1N1, H1N2, and H3N2). Genetic analysis can distinguish animal origin influenza viruses from the seasonal human influenza viruses that circulate widely and cause annual epidemics. This report describes two cases of febrile respiratory illness caused by swine-origin influenza A (H3N2) viruses identified on August 19 and August 26, 2011, and the current investigations. No epidemiologic link between the two cases has been identified, and although investigations are ongoing, no additional confirmed human infections with this virus have been detected. These viruses are similar to eight other swine-origin influenza A (H3N2) viruses identified from previous human infections over the past 2 years, but are unique in that one of the eight gene segments (matrix [M] gene) is from the 2009 influenza A (H1N1) virus. The acquisition of the M gene in these two swine-origin influenza A (H3N2) viruses indicates that they are "reassortants" because they contain genes of the swine-origin influenza A (H3N2) virus circulating in North American pigs since 1998 and the 2009 influenza A (H1N1) virus that might have been transmitted to pigs from humans during the 2009 H1N1 pandemic. However, reassortments of the 2009 influenza A (H1N1) virus with other swine influenza A viruses have been reported previously in swine. Clinicians who suspect influenza virus infection in humans with recent exposure to swine should obtain a nasopharyngeal swab from the patient for timely diagnosis at a state public health laboratory and consider empiric neuraminidase inhibitor antiviral treatment to quickly limit potential human transmission.

  3. Polymerase Discordance in Novel Swine Influenza H3N2v Constellations Is Tolerated in Swine but Not Human Respiratory Epithelial Cells

    PubMed Central

    Powell, Joshua D.; Dlugolenski, Daniel; Nagy, Tamas; Gabbard, Jon; Lee, Christopher; Tompkins, Stephen M.; Tripp, Ralph A.

    2014-01-01

    Swine-origin H3N2v, a variant of H3N2 influenza virus, is a concern for novel reassortment with circulating pandemic H1N1 influenza virus (H1N1pdm09) in swine because this can lead to the emergence of a novel pandemic virus. In this study, the reassortment prevalence of H3N2v with H1N1pdm09 was determined in swine cells. Reassortants evaluated showed that the H1N1pdm09 polymerase (PA) segment occurred within swine H3N2 with ∼80% frequency. The swine H3N2-human H1N1pdm09 PA reassortant (swH3N2-huPA) showed enhanced replication in swine cells, and was the dominant gene constellation. Ferrets infected with swH3N2-huPA had increased lung pathogenicity compared to parent viruses; however, swH3N2-huPA replication in normal human bronchoepithelial cells was attenuated - a feature linked to expression of IFN-β and IFN-λ genes in human but not swine cells. These findings indicate that emergence of novel H3N2v influenza constellations require more than changes in the viral polymerase complex to overcome barriers to cross-species transmission. Additionally, these findings reveal that while the ferret model is highly informative for influenza studies, slight differences in pathogenicity may not necessarily be indicative of human outcomes after infection. PMID:25330303

  4. Swine influenza virus vaccine serologic cross-reactivity to contemporary US swine H3N2 and efficacy in pigs infected with an H3N2 similar to 2011-2012 H3N2v.

    PubMed

    Kitikoon, Pravina; Gauger, Phillip C; Anderson, Tavis K; Culhane, Marie R; Swenson, Sabrina; Loving, Crystal L; Perez, Daniel R; Vincent, Amy L

    2013-12-01

    Swine influenza A virus (IAV) reassortment with 2009 H1N1 pandemic (H1N1pdm09) virus has been documented, and new genotypes and subclusters of H3N2 have since expanded in the US swine population. An H3N2 variant (H3N2v) virus with the H1N1pdm09 matrix gene and the remaining genes of swine triple reassortant H3N2 caused outbreaks at agricultural fairs in 2011-2012. To assess commercial swine IAV vaccines' efficacy against H3N2 viruses, including those similar to H3N2v, antisera to three vaccines were tested by hemagglutinin inhibition (HI) assay against contemporary H3N2. Vaccine 1, with high HI cross-reactivity, was further investigated for efficacy against H3N2 virus infection in pigs with or without maternally derived antibodies (MDA). In addition, efficacy of a vaccine derived from whole inactivated virus (WIV) was compared with live attenuated influenza virus (LAIV) against H3N2. Hemagglutinin inhibition cross-reactivity demonstrated that contemporary swine H3N2 viruses have drifted from viruses in current swine IAV vaccines. The vaccine with the highest level of HI cross-reactivity significantly protected pigs without MDA. However, the presence of MDA at vaccination blocked vaccine efficacy. The performance of WIV and LAIV was comparable in the absence of MDA. Swine IAV in the United States is complex and dynamic. Vaccination to minimize virus shedding can help limit transmission of virus among pigs and people. However, vaccines must be updated. A critical review of the use of WIV in sows is required in the context of the current IAV ecology and vaccine application in pigs with MDA. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  5. Swine influenza virus vaccine serologic cross-reactivity to contemporary U.S. swine H3N2 and efficacy in pigs infected with an H3N2 similar to 2011-2012 H3N2v

    USDA-ARS?s Scientific Manuscript database

    Background: Swine influenza A virus (IAV) reassortment with 2009 H1N1 pandemic (H1N1pdm09) virus has been documented and new genotypes and sub-clusters of H3N2 have since expanded in the U.S. swine population. An H3N2 variant (H3N2v) virus with the H1N1pdm09 matrix gene and the remaining genes of sw...

  6. Two genotypes of H1N2 swine influenza viruses appeared among pigs in China.

    PubMed

    Xu, Chuantian; Zhu, Qiyun; Yang, Huanliang; Zhang, Xiumei; Qiao, Chuanling; Chen, Yan; Xin, Xiaoguang; Chen, Hualan

    2009-10-01

    H1N2 is one of the main subtypes of influenza, which circulates in swine all over the world. To investigate the prevalence and genetic of H1N2 in swine of China. Two H1N2 swine influenza viruses were isolated from Tianjin and Guangdong province of China in 2004 and 2006, respectively. The molecular evolution of eight gene segments was analyzed. A/Swine/Tianjin/1/2004 has low identity with A/Swine/Guangdong/2006; in the phylogenetic tree of PA gene, A/Swine/Guangdong/1/2006 and A/Swine/Guangxi/1/2006 along with the H1N2 swine isolates of North America formed a cluster; and A/Swine/Tianjin/2004 and A/Swine/Zhejiang/2004, along with the classical H1N1 swine isolates formed another cluster; except that NA gene of A/Swine/Tianjin/1/2004 fell into the cluster of the H3N2 human influenza virus, indicating the reassortment between H3N2 human and H1N1 swine influenza viruses. Two different genotypes of H1N2 appeared among pigs in China. A/swine/Guangdong/1/06 was probably from H1N2 swine influenza viruses of North America; while A/swine/Tianjin/1/04 maybe come from reassortments of classical H1N1 swine and H3N2 human viruses prevalent in North America.

  7. Swine-to-Human Transmission of Influenza A(H3N2) Virus at Agricultural Fairs, Ohio, USA, 2012

    PubMed Central

    Nelson, Sarah W.; Page, Shannon L.; Nolting, Jacqueline M.; Killian, Mary L.; Sreevatsan, Srinand; Slemons, Richard D.

    2014-01-01

    Agricultural fairs provide an opportunity for bidirectional transmission of influenza A viruses. We sought to determine influenza A virus activity among swine at fairs in the United States. As part of an ongoing active influenza A virus surveillance project, nasal swab samples were collected from exhibition swine at 40 selected Ohio agricultural fairs during 2012. Influenza A(H3N2) virus was isolated from swine at 10 of the fairs. According to a concurrent public health investigation, 7 of the 10 fairs were epidemiologically linked to confirmed human infections with influenza A(H3N2) variant virus. Comparison of genome sequences of the subtype H3N2 isolates recovered from humans and swine from each fair revealed nucleotide identities of >99.7%, confirming zoonotic transmission between swine and humans. All influenza A(H3N2) viruses isolated in this study, regardless of host species or fair, were >99.5% identical, indicating that 1 virus strain was widely circulating among exhibition swine in Ohio during 2012. PMID:25148572

  8. Novel reassortant of swine influenza H1N2 virus in Germany.

    PubMed

    Zell, Roland; Motzke, Susann; Krumbholz, Andi; Wutzler, Peter; Herwig, Volker; Dürrwald, Ralf

    2008-01-01

    European porcine H1N2 influenza viruses arose after multiple reassortment steps involving a porcine influenza virus with avian-influenza-like internal segments and human H1N1 and H3N2 viruses in 1994. In Germany, H1N2 swine influenza viruses first appeared in 2000. Two German H1N2 swine influenza virus strains isolated from pigs with clinical symptoms of influenza are described. They were characterized by the neutralization test, haemagglutination inhibition (HI) test and complete sequencing of the viral genomes. The data demonstrate that these viruses represent a novel H1N2 reassortant. The viruses showed limited neutralization by sera raised against heterologous A/sw/Bakum/1,832/00-like H1N2 viruses. Sera pools from recovered pigs showed a considerably lower HI reaction, indicative of diagnostic difficulties in using the HI test to detect these viruses with A/sw/Bakum/1,832/00-like H1N2 antigens. Genome sequencing revealed the novel combination of the human-like HAH1 gene of European porcine H1N2 influenza viruses and the NAN2 gene of European porcine H3N2 viruses.

  9. Evolution of Novel Reassortant A/H3N2 Influenza Viruses in North American Swine and Humans, 2009–2011

    PubMed Central

    Vincent, Amy L.; Kitikoon, Pravina; Holmes, Edward C.; Gramer, Marie R.

    2012-01-01

    Novel H3N2 influenza viruses (H3N2v) containing seven genome segments from swine lineage triple-reassortant H3N2 viruses and a 2009 pandemic H1N1 (H1N1pdm09) matrix protein segment (pM) were isolated from 12 humans in the United States between August and December 2011. To understand the evolution of these novel H3N2 viruses in swine and humans, we undertook a phylogenetic analysis of 674 M sequences and 388 HA and NA sequences from influenza viruses isolated from North American swine during 2009–2011, as well as HA, NA, and M sequences from eight H3N2v viruses isolated from humans. We identified 34 swine influenza viruses (termed rH3N2p) with the same combination of H3, N2, and pM segments as the H3N2v viruses isolated from humans. Notably, these rH3N2p viruses were generated in swine via reassortment events between H3N2 viruses and the pM segment approximately 4 to 10 times since 2009. The pM segment has also reassorted with multiple distinct lineages of H1 virus, especially H1δ viruses. Importantly, the N2 segment of all H3N2v viruses isolated from humans is derived from a genetically distinct N2 lineage that has circulated in swine since being acquired by reassortment with seasonal human H3N2 viruses in 2001–2002, rather than from the N2 that is associated with the 1998 H3N2 swine lineage. The identification of this N2 variant may have implications for influenza vaccine design and the potential pandemic threat of H3N2v to human age groups with differing levels of prior exposure and immunity. PMID:22696653

  10. Phylogenetic Analysis of a Swine Influenza A(H3N2) Virus Isolated in Korea in 2012

    PubMed Central

    Park, Sehee; Lee, Sangmoo; Hwang, Min-Woong; Bae, Joon-Yong; Heo, Jun; Kim, Donghwan; Jang, Seok-Il; Kim, Kabsu; Park, Man-Seong

    2014-01-01

    Influenza A virus (IAV) can infect avian and mammalian species, including humans. The genome nature of IAVs may contribute to viral adaptation in different animal hosts, resulting in gene reassortment and the reproduction of variants with optimal fitness. As seen again in the 2009 swine-origin influenza A H1N1 pandemic, pigs are known to be susceptible to swine, avian, and human IAVs and can serve as a ‘mixing vessel’ for the generation of novel IAV variants. To this end, the emergence of swine influenza viruses must be kept under close surveillance. Herein, we report the isolation and phylogenetic study of a swine IAV, A/swine/Korea/PL01/2012 (swPL01, H3N2 subtype). After screening nasopharyngeal samples from pigs in the Gyeongsangnam-do region of Korea from December 2011 to May 2012, we isolated the swPL01 virus and sequenced its all of 8 genome segments (polymerase basic 2, PB2; polymerase basic 1, PB1; polymerase acidic, PA; hemagglutinin, HA; nucleocapsid protein, NP; neuraminidase, NA; matrix protein, M; and nonstructural protein, NS). The phylogenetic study, analyzed with reference strains registered in the National Center for Biotechnology Information (NCBI) database, indicated that the swPL01 virus was similar to the North American triple-reassortant swine strains and that the HA gene of the swPL01 virus was categorized into swine H3 cluster IV. The swPL01 virus had the M gene of the triple-reassortant swine H3N2 viruses, whereas that of other contemporary strains in Korea was transferred from the 2009 pandemic H1N1 virus. These data suggest the possibility that various swine H3N2 viruses may co-circulate in Korea, which underlines the importance of a sustained surveillance system against swine IAVs. PMID:24523938

  11. Identification of four genotypes of H3N2 swine influenza virus in pigs from southern China.

    PubMed

    Chen, Jidang; Fu, Xinliang; Chen, Ye; He, Shuyi; Zheng, Yun; Cao, Zhenpeng; Yu, Wenxin; Zhou, Han; Su, Shuo; Zhang, Guihong

    2014-10-01

    In 2011, four H3N2 swine influenza viruses (SIVs) were isolated from nasal swabs of four pigs (800 nasal swabs were collected from pigs showing influenza-like symptoms) in Guangdong province, China. Four different genotypes of H3N2 appeared among pigs in southern China, including wholly human-like H3N2 viruses, intermediate (1975) double-reassortant human H3N2 viruses (resulting from reassortment between an early human lineage and a recent human lineage), recent double-reassortant human H3N2 viruses, and avian-like H3N2 viruses. Because pigs can support the reassortment of human and avian influenza viruses, our surveillance should be enhanced as a part of an overall pandemic preparedness plan.

  12. Influenza A (H3N2) virus in swine at agricultural fairs and transmission to humans, Michigan and Ohio, USA, 2016

    USDA-ARS?s Scientific Manuscript database

    An 18 case outbreak of variant H3N2 influenza A occurred during 2016 after exposure to influenza-infected swine at seven agricultural fairs. Sixteen cases were infected with a reassortant between 2010-2011 human seasonal H3N2 strains and viruses endemic in North American swine, a viral lineage incre...

  13. Swine Influenza Virus (H1N2) Characterization and Transmission in Ferrets, Chile.

    PubMed

    Bravo-Vasquez, Nicolás; Karlsson, Erik A; Jimenez-Bluhm, Pedro; Meliopoulos, Victoria; Kaplan, Bryan; Marvin, Shauna; Cortez, Valerie; Freiden, Pamela; Beck, Melinda A; Hamilton-West, Christopher; Schultz-Cherry, Stacey

    2017-02-01

    Phylogenetic analysis of the influenza hemagglutinin gene (HA) has suggested that commercial pigs in Chile harbor unique human seasonal H1-like influenza viruses, but further information, including characterization of these viruses, was unavailable. We isolated influenza virus (H1N2) from a swine in a backyard production farm in Central Chile and demonstrated that the HA gene was identical to that in a previous report. Its HA and neuraminidase genes were most similar to human H1 and N2 viruses from the early 1990s and internal segments were similar to influenza A(H1N1)pdm09 virus. The virus replicated efficiently in vitro and in vivo and transmitted in ferrets by respiratory droplet. Antigenically, it was distinct from other swine viruses. Hemagglutination inhibition analysis suggested that antibody titers to the swine Chilean H1N2 virus were decreased in persons born after 1990. Further studies are needed to characterize the potential risk to humans, as well as the ecology of influenza in swine in South America.

  14. Swine Influenza Virus (H1N2) Characterization and Transmission in Ferrets, Chile

    PubMed Central

    Bravo-Vasquez, Nicolás; Karlsson, Erik A.; Jimenez-Bluhm, Pedro; Meliopoulos, Victoria; Kaplan, Bryan; Marvin, Shauna; Cortez, Valerie; Freiden, Pamela; Beck, Melinda A.

    2017-01-01

    Phylogenetic analysis of the influenza hemagglutinin gene (HA) has suggested that commercial pigs in Chile harbor unique human seasonal H1-like influenza viruses, but further information, including characterization of these viruses, was unavailable. We isolated influenza virus (H1N2) from a swine in a backyard production farm in Central Chile and demonstrated that the HA gene was identical to that in a previous report. Its HA and neuraminidase genes were most similar to human H1 and N2 viruses from the early 1990s and internal segments were similar to influenza A(H1N1)pdm09 virus. The virus replicated efficiently in vitro and in vivo and transmitted in ferrets by respiratory droplet. Antigenically, it was distinct from other swine viruses. Hemagglutination inhibition analysis suggested that antibody titers to the swine Chilean H1N2 virus were decreased in persons born after 1990. Further studies are needed to characterize the potential risk to humans, as well as the ecology of influenza in swine in South America. PMID:28098524

  15. The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant.

    PubMed

    Bálint, Adám; Metreveli, Giorgi; Widén, Frederik; Zohari, Siamak; Berg, Mikael; Isaksson, Mats; Renström, Lena Hm; Wallgren, Per; Belák, Sándor; Segall, Thomas; Kiss, István

    2009-10-28

    The European swine influenza viruses (SIVs) show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority of the European H1N2 swine influenza viruses described so far possess haemagglutinin (HA) of the human-like H1N2 SIV viruses and the neuraminidase (NA) of either the European H1N2 or H3N2 SIV-like viruses. The Swedish isolate has an avian-like SIV HA and a H3N2 SIV-like NA, which is phylogenetically more closely related to H3N2 SIV NAs from isolates collected in the early '80s than to the NA of H3N2 origin of the H1N2 viruses isolated during the last decade, as depicted by some German strains, indicative of independent acquisition of the NA genes for these two types of reassortants. The internal genes proved to be entirely of avian-like SIV H1N1 origin. The prevalence of this SIV variant in pig populations needs to be determined, as well as the suitability of the routinely used laboratory reagents to analyze this strain.The description of this H1N2 SIV adds further information to influenza epidemiology and supports the necessity of surveillance for influenza viruses in pigs.

  16. Reassortment process after co-infection of pigs with avian H1N1 and swine H3N2 influenza viruses.

    PubMed

    Urbaniak, Kinga; Markowska-Daniel, Iwona; Kowalczyk, Andrzej; Kwit, Krzysztof; Pomorska-Mól, Małgorzata; Frącek, Barbara; Pejsak, Zygmunt

    2017-07-08

    The influenza A virus is highly variable, which, to some degree, is caused by the reassortment of viral genetic material. This process plays a major role in the generation of novel influenza virus strains that can emerge in a new host population. Due to the susceptibility of pigs to infections with avian, swine and human influenza viruses, they are considered intermediate hosts for the adaptation of the avian influenza virus to humans. In order to test the reassortment process in pigs, they were co-infected with H3N2 A/swine/Gent/172/2008 (Gent/08) and H1N1 A/duck/Italy/1447/2005 (Italy/05) and co-housed with a group of naïve piglets. The Gent/08 strains dominated over Italy/05, but reassortment occurred. The reassortant strains of the H1N1 subtype (12.5%) with one gene (NP or M) of swine-origin were identified in the nasal discharge of the contact-exposed piglets. These results demonstrate that despite their low efficiency, genotypically and phenotypically different influenza A viruses can undergo genetic exchange during co-infection of pigs.

  17. Prior infection of pigs with a recent human H3N2 influenza virus confers minimal cross-protection against a European swine H3N2 virus.

    PubMed

    Qiu, Yu; van der Meulen, Karen; Van Reeth, Kristien

    2013-11-01

    H3N2 influenza viruses circulating in humans and European pigs originate from the pandemic A/Hong Kong/68 virus. Because of slower antigenic drift in swine, the antigenic divergence between swine and human viruses has been increasing. It remains unknown to what extent this results in a reduced cross-protection between recent human and swine H3N2 influenza viruses. We examined whether prior infection of pigs with an old [A/Victoria/3/75 (A/Vic/75)] or a more recent [A/Wisconsin/67/05 (A/Wis/05)] human H3N2 virus protected against a European swine H3N2 virus [sw/Gent/172/08 (sw/Gent/08)]. Genetic and antigenic relationships between sw/Gent/08 and a selection of human H3N2 viruses were also assessed. After challenge with sw/Gent/08, all challenge controls had high virus titers in the entire respiratory tract at 3 days post-challenge and nasal virus excretion for 5-6 days. Prior infection with sw/Gent/08 or A/Vic/75 offered complete virological protection against challenge. Pigs previously inoculated with A/Wis/05 showed similar virus titers in the respiratory tract as challenge controls, but the mean duration of nasal shedding was 1·3 days shorter. Unlike sw/Gent/08- and A/Vic/75-inoculated pigs, A/Wis/05-inoculated pigs lacked cross-reactive neutralizing antibodies against sw/Gent/08 before challenge, but they showed a more rapid antibody response to sw/Gent/08 than challenge controls after challenge. Cross-protection and serological responses correlated with genetic and antigenic differences. Infection immunity to a recent human H3N2 virus confers minimal cross-protection against a European swine H3N2 virus. We discuss our findings with regard to the recent zoonotic infections of humans in the United States with a swine-origin H3N2 variant virus. © 2013 John Wiley & Sons Ltd.

  18. Influenza A(H3N2) Virus in Swine at Agricultural Fairs and Transmission to Humans, Michigan and Ohio, USA, 2016

    PubMed Central

    Walia, Rasna R.; Nolting, Jacqueline M.; Vincent, Amy L.; Killian, Mary Lea; Zentkovich, Michele M.; Lorbach, Joshua N.; Lauterbach, Sarah E.; Anderson, Tavis K.; Davis, C. Todd; Zanders, Natosha; Jones, Joyce; Jang, Yunho; Lynch, Brian; Rodriguez, Marisela R.; Blanton, Lenee; Lindstrom, Stephen E.; Wentworth, David E.; Schiltz, John; Averill, James J.; Forshey, Tony

    2017-01-01

    In 2016, a total of 18 human infections with influenza A(H3N2) virus occurred after exposure to influenza-infected swine at 7 agricultural fairs. Sixteen of these cases were the result of infection by a reassorted virus with increasing prevalence among US swine containing a hemagglutinin gene from 2010–11 human seasonal H3N2 strains. PMID:28820376

  19. Swine Influenza (H3N2) Infection in a Child and Possible Community Transmission, Canada

    PubMed Central

    Lee, Bonita E.; Patel, Jagdish; Bastien, Nathalie; Grimsrud, Karen; Seal, Robert F.; King, Robin; Marshall, Frank; Li, Yan

    2007-01-01

    An influenza A virus (H3N2) of probable swine origin, designated A/Canada/1158/2006, was isolated from a 7-month-old hospitalized child who lived on a communal farm in Canada. The child recovered uneventfully. A serosurvey that used a hemagglutination-inhibition assay for A/Canada/1158/2006 was conducted on 54 of the 90 members of the farm. Seropositivity was demonstrated in the index patient, 4 of 7 household members, and 4 of 46 nonhousehold members; none had a history of hospital admission for respiratory illness in the preceding year. Serologic evidence for this strain of swine influenza was also found in 1 of 10 pigs (12 weeks–6 months of age) on the farm. Human infection with swine influenza virus is underrecognized in Canada, and because viral strains could adapt or reassort into a form that results in efficient human-to-human transmission, routine surveillance of swine workers should be considered as part of pandemic influenza preparedness. PMID:18258037

  20. Influenza A (H3N2) Variant Virus

    MedlinePlus

    ... When Planning Fairs Key Facts for People Exhibiting Pigs at Fairs News & Highlights Materials & Resources Publications & Resources ... What's this? Submit Button Influenza Types Seasonal Avian Swine Variant Pandemic Other Influenza A (H3N2) Variant Virus ...

  1. Antigenic variation of H1N1, H1N2 and H3N2 swine influenza viruses in Japan and Vietnam.

    PubMed

    Takemae, Nobuhiro; Nguyen, Tung; Ngo, Long Thanh; Hiromoto, Yasuaki; Uchida, Yuko; Pham, Vu Phong; Kageyama, Tsutomu; Kasuo, Shizuko; Shimada, Shinichi; Yamashita, Yasutaka; Goto, Kaoru; Kubo, Hideyuki; Le, Vu Tri; Van Vo, Hung; Do, Hoa Thi; Nguyen, Dang Hoang; Hayashi, Tsuyoshi; Matsuu, Aya; Saito, Takehiko

    2013-04-01

    The antigenicity of the influenza A virus hemagglutinin is responsible for vaccine efficacy in protecting pigs against swine influenza virus (SIV) infection. However, the antigenicity of SIV strains currently circulating in Japan and Vietnam has not been well characterized. We examined the antigenicity of classical H1 SIVs, pandemic A(H1N1)2009 (A(H1N1)pdm09) viruses, and seasonal human-lineage SIVs isolated in Japan and Vietnam. A hemagglutination inhibition (HI) assay was used to determine antigenic differences that differentiate the recent Japanese H1N2 and H3N2 SIVs from the H1N1 and H3N2 domestic vaccine strains. Minor antigenic variation between pig A(H1N1)pdm09 viruses was evident by HI assay using 13 mAbs raised against homologous virus. A Vietnamese H1N2 SIV, whose H1 gene originated from a human strain in the mid-2000s, reacted poorly with post-infection ferret serum against human vaccine strains from 2000-2010. These results provide useful information for selection of optimal strains for SIV vaccine production.

  2. Viral reassortment and transmission after co-infection of pigs with classical H1N1 and triple-reassortant H3N2 swine influenza viruses.

    PubMed

    Ma, Wenjun; Lager, Kelly M; Lekcharoensuk, Porntippa; Ulery, Eva S; Janke, Bruce H; Solórzano, Alicia; Webby, Richard J; García-Sastre, Adolfo; Richt, Jürgen A

    2010-09-01

    Triple-reassortant swine influenza viruses circulating in North American pigs contain the internal genes derived from swine (matrix, non-structural and nucleoprotein), human [polymerase basic 1 (PB1)] and avian (polymerase acidic and PB2) influenza viruses forming a constellation of genes that is well conserved and is called the triple-reassortant internal gene (TRIG) cassette. In contrast, the external genes [haemagglutinin (HA) and neuraminidase (NA)] are less conserved, reflecting multiple reassortant events that have produced viruses with different combinations of HA and NA genes. This study hypothesized that maintenance of the TRIG cassette confers a selective advantage to the virus. To test this hypothesis, pigs were co-infected with the triple-reassortant H3N2 A/Swine/Texas/4199-2/98 (Tx/98) and the classical H1N1 A/Swine/Iowa/15/1930 viruses and co-housed with a group of sentinel animals. This direct contact group was subsequently moved into contact with a second group of naïve animals. Four different subtypes (H1N1, H1N2, H3N1 and H3N2) of influenza virus were identified in bronchoalveolar lavage fluid collected from the lungs of the experimentally infected pigs, with most of the viruses containing TRIG from the Tx/98 virus. Interestingly, only the intact H3N2 Tx/98 virus was transmitted from the infected pigs to the direct-contact animals and from them to the second contact group of pigs. These results demonstrated that multiple reassortments can occur within a host; however, only specific gene constellations are readily transmissible. It was concluded that certain HA and NA gene pairs, in conjunction with the TRIG cassette, may have a competitive advantage over other combinations for transmission and maintenance in swine.

  3. Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

    PubMed

    Cappuccio, Javier A; Pena, Lindomar; Dibárbora, Marina; Rimondi, Agustina; Piñeyro, Pablo; Insarralde, Lucas; Quiroga, María A; Machuca, Mariana; Craig, Maria I; Olivera, Valeria; Chockalingam, Ashok; Perfumo, Carlos J; Perez, Daniel R; Pereda, Ariel

    2011-12-01

    Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96-98 % with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with non-contemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.

  4. Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs

    PubMed Central

    Cappuccio, Javier A.; Pena, Lindomar; Dibárbora, Marina; Rimondi, Agustina; Piñeyro, Pablo; Insarralde, Lucas; Quiroga, María A.; Machuca, Mariana; Craig, Maria I.; Olivera, Valeria; Chockalingam, Ashok; Perfumo, Carlos J.

    2011-01-01

    Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96–98 % with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with non-contemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide. PMID:21849519

  5. Comparative pathology of pigs infected with Korean H1N1, H1N2, or H3N2 swine influenza A viruses.

    PubMed

    Lyoo, Kwang-Soo; Kim, Jeong-Ki; Jung, Kwonil; Kang, Bo-Kyu; Song, Daesub

    2014-09-24

    The predominant subtypes of swine influenza A virus (SIV) in Korea swine population are H1N1, H1N2, and H3N2. The viruses are genetically close to the classical U.S. H1N1 and triple-reassortant H1N2 and H3N2 viruses, respectively. Comparative pathogenesis caused by Korean H1N1, H1N2, and H3N2 SIV was evaluated in this study. The H3N2 infected pigs had severe scores of gross and histopathological lesions at post-inoculation days (PID) 2, and this then progressively decreased. Both the H1N1 and H1N2 infected pigs lacked gross lesions at PID 2, but they showed moderate to severe pneumonia on PID 4, 7 and 14. The pigs infected with H1N1 had significant scores of gross and histopathological lesions when compared with the other pigs infected with H1N2, H3N2, and mock at PID 14. Mean SIV antigen-positive scores were rarely detected for pigs infected with H1N2 and H3N2 from PID 7, whereas a significantly increased amount of viral antigens were found in the bronchioles and alveolar epithelium of the H1N1infected pigs at PID 14. We demonstrated that Korean SIV subtypes had different pulmonary pathologic patterns. The Korean H3N2 rapidly induced acute lung lesions such as broncho-interstitial pneumonia, while the Korean H1N1 showed longer course of infection as compared to other strains.

  6. The avian-origin H3N2 canine influenza virus has limited replication in swine

    USDA-ARS?s Scientific Manuscript database

    A genetically and antigenically distinct H3N2 canine influenza of avian-origin was detected in March of 2015 in Chicago, Illinois. A subsequent outbreak was reported with over 1,000 dogs in the Midwest affected. The potential for canine-to-swine transmission was unknown. Experimental infection in pi...

  7. Molecular characterization of a novel reassortant H1N2 influenza virus containing genes from the 2009 pandemic human H1N1 virus in swine from eastern China.

    PubMed

    Peng, Xiuming; Wu, Haibo; Xu, Lihua; Peng, Xiaorong; Cheng, Linfang; Jin, Changzhong; Xie, Tiansheng; Lu, Xiangyun; Wu, Nanping

    2016-06-01

    Pandemic outbreaks of H1N1 swine influenza virus have been reported since 2009. Reassortant H1N2 viruses that contain genes from the pandemic H1N1 virus have been isolated in Italy and the United States. However, there is limited information regarding the molecular characteristics of reassortant H1N2 swine influenza viruses in eastern China. Active influenza surveillance programs in Zhejiang Province identified a novel H1N2 influenza virus isolated from pigs displaying clinical signs of influenza virus infection. Whole-genome sequencing was performed and this strain was compared with other influenza viruses available in GenBank. Phylogenetic analysis suggested that the novel strain contained genes from the 2009 pandemic human H1N1 and swine H3N2 viruses. BALB/c mice were infected with the isolated virus to assess its virulence in mice. While the novel H1N2 isolate replicated well in mice, it was found to be less virulent. These results provide additional evidence that swine serve as intermediate hosts or 'mixing vessels' for novel influenza viruses. They also emphasize the importance of surveillance in the swine population for use as an early warning system for influenza outbreaks in swine and human populations.

  8. [Swine-origin influenza H1N1/California--passions and facts].

    PubMed

    Gendon, Iu Z

    2010-01-01

    Analysis of pandemic caused by swine influenza virus H1N1/California showed moderate virulence of this virus compared to pandemic viruses, which caused pandemics in 1918, 1957, and 1968. During seasonal influenza epidemic in countries of southern hemisphere (June-August 2009) despite on circulation of H1N1/California strain, epidemics was caused by human influenza viruses H3N2 and H1N1. It was concluded that strain H1N1/California could not be attributed to pandemic strains of influenza viruses.

  9. Human T-cells directed to seasonal influenza A virus cross-react with 2009 pandemic influenza A (H1N1) and swine-origin triple-reassortant H3N2 influenza viruses.

    PubMed

    Hillaire, Marine L B; Vogelzang-van Trierum, Stella E; Kreijtz, Joost H C M; de Mutsert, Gerrie; Fouchier, Ron A M; Osterhaus, Albert D M E; Rimmelzwaan, Guus F

    2013-03-01

    Virus-specific CD8(+) T-cells contribute to protective immunity against influenza A virus (IAV) infections. As the majority of these cells are directed to conserved viral proteins, they may afford protection against IAVs of various subtypes. The present study assessed the cross-reactivity of human CD8(+) T-lymphocytes, induced by infection with seasonal A (H1N1) or A (H3N2) influenza virus, with 2009 pandemic influenza A (H1N1) virus [A(H1N1)pdm09] and swine-origin triple-reassortant A (H3N2) [A(H3N2)v] viruses that are currently causing an increasing number of human cases in the USA. It was demonstrated that CD8(+) T-cells induced after seasonal IAV infections exerted lytic activity and produced gamma interferon upon in vitro restimulation with A(H1N1)pdm09 and A(H3N2)v influenza A viruses. Furthermore, CD8(+) T-cells directed to A(H1N1)pdm09 virus displayed a high degree of cross-reactivity with A(H3N2)v viruses. It was concluded that cross-reacting T-cells had the potential to afford protective immunity against A(H1N1)pdm09 viruses during the pandemic and offer some degree of protection against infection with A(H3N2)v viruses.

  10. Genetic evolution of recently emerged novel human-like swine H3 influenza A viruses (IAV) in United States swine

    USDA-ARS?s Scientific Manuscript database

    Introduction Influenza A virus (IAV) is a major cause of respiratory disease in swine. IAV transmission from humans to swine is a major contributor to swine IAV diversity. In 2012, a novel H3N2 with an HA (hu-H3) and NA derived from human seasonal H3N2 was detected in United States (US) swine. The h...

  11. Genotype patterns of contemporary reassorted H3N2 virus in U.S. swine

    USDA-ARS?s Scientific Manuscript database

    To understand the evolution of H3N2v influenza viruses that have infected 288 humans since July 2011, we performed the largest phylogenetic analysis at a whole genome scale of influenza viruses from North American swine to date (n = 200). At least ten distinct reassorted H3N2/pandemic H1N1 (rH3N2p)...

  12. Novel Reassortant Human-Like H3N2 and H3N1 Influenza A Viruses Detected in Pigs Are Virulent and Antigenically Distinct from Swine Viruses Endemic to the United States

    PubMed Central

    Rajão, Daniela S.; Gauger, Phillip C.; Anderson, Tavis K.; Lewis, Nicola S.; Abente, Eugenio J.; Killian, Mary Lea; Sutton, Troy C.; Zhang, Jianqiang

    2015-01-01

    ABSTRACT Human-like swine H3 influenza A viruses (IAV) were detected by the USDA surveillance system. We characterized two novel swine human-like H3N2 and H3N1 viruses with hemagglutinin (HA) genes similar to those in human seasonal H3 strains and internal genes closely related to those of 2009 H1N1 pandemic viruses. The H3N2 neuraminidase (NA) was of the contemporary human N2 lineage, while the H3N1 NA was of the classical swine N1 lineage. Both viruses were antigenically distant from swine H3 viruses that circulate in the United States and from swine vaccine strains and also showed antigenic drift from human seasonal H3N2 viruses. Their pathogenicity and transmission in pigs were compared to those of a human H3N2 virus with a common HA ancestry. Both swine human-like H3 viruses efficiently infected pigs and were transmitted to indirect contacts, whereas the human H3N2 virus did so much less efficiently. To evaluate the role of genes from the swine isolates in their pathogenesis, reverse genetics-generated reassortants between the swine human-like H3N1 virus and the seasonal human H3N2 virus were tested in pigs. The contribution of the gene segments to virulence was complex, with the swine HA and internal genes showing effects in vivo. The experimental infections indicate that these novel H3 viruses are virulent and can sustain onward transmission in pigs, and the naturally occurring mutations in the HA were associated with antigenic divergence from H3 IAV from humans and swine. Consequently, these viruses could have a significant impact on the swine industry if they were to cause more widespread outbreaks, and the potential risk of these emerging swine IAV to humans should be considered. IMPORTANCE Pigs are important hosts in the evolution of influenza A viruses (IAV). Human-to-swine transmissions of IAV have resulted in the circulation of reassortant viruses containing human-origin genes in pigs, greatly contributing to the diversity of IAV in swine worldwide

  13. Novel Reassortant Human-Like H3N2 and H3N1 Influenza A Viruses Detected in Pigs Are Virulent and Antigenically Distinct from Swine Viruses Endemic to the United States.

    PubMed

    Rajão, Daniela S; Gauger, Phillip C; Anderson, Tavis K; Lewis, Nicola S; Abente, Eugenio J; Killian, Mary Lea; Perez, Daniel R; Sutton, Troy C; Zhang, Jianqiang; Vincent, Amy L

    2015-11-01

    Human-like swine H3 influenza A viruses (IAV) were detected by the USDA surveillance system. We characterized two novel swine human-like H3N2 and H3N1 viruses with hemagglutinin (HA) genes similar to those in human seasonal H3 strains and internal genes closely related to those of 2009 H1N1 pandemic viruses. The H3N2 neuraminidase (NA) was of the contemporary human N2 lineage, while the H3N1 NA was of the classical swine N1 lineage. Both viruses were antigenically distant from swine H3 viruses that circulate in the United States and from swine vaccine strains and also showed antigenic drift from human seasonal H3N2 viruses. Their pathogenicity and transmission in pigs were compared to those of a human H3N2 virus with a common HA ancestry. Both swine human-like H3 viruses efficiently infected pigs and were transmitted to indirect contacts, whereas the human H3N2 virus did so much less efficiently. To evaluate the role of genes from the swine isolates in their pathogenesis, reverse genetics-generated reassortants between the swine human-like H3N1 virus and the seasonal human H3N2 virus were tested in pigs. The contribution of the gene segments to virulence was complex, with the swine HA and internal genes showing effects in vivo. The experimental infections indicate that these novel H3 viruses are virulent and can sustain onward transmission in pigs, and the naturally occurring mutations in the HA were associated with antigenic divergence from H3 IAV from humans and swine. Consequently, these viruses could have a significant impact on the swine industry if they were to cause more widespread outbreaks, and the potential risk of these emerging swine IAV to humans should be considered. Pigs are important hosts in the evolution of influenza A viruses (IAV). Human-to-swine transmissions of IAV have resulted in the circulation of reassortant viruses containing human-origin genes in pigs, greatly contributing to the diversity of IAV in swine worldwide. New human-like H3N2

  14. Detection of Antigenic Variants of Subtype H3 Swine Influenza A Viruses from Clinical Samples

    PubMed Central

    Martin, Brigitte E.; Li, Lei; Nolting, Jacqueline M.; Smith, David R.; Hanson, Larry A.

    2017-01-01

    ABSTRACT A large population of genetically and antigenically diverse influenza A viruses (IAVs) are circulating among the swine population, playing an important role in influenza ecology. Swine IAVs not only cause outbreaks among swine but also can be transmitted to humans, causing sporadic infections and even pandemic outbreaks. Antigenic characterizations of swine IAVs are key to understanding the natural history of these viruses in swine and to selecting strains for effective vaccines. However, influenza outbreaks generally spread rapidly among swine, and the conventional methods for antigenic characterization require virus propagation, a time-consuming process that can significantly reduce the effectiveness of vaccination programs. We developed and validated a rapid, sensitive, and robust method, the polyclonal serum-based proximity ligation assay (polyPLA), to identify antigenic variants of subtype H3N2 swine IAVs. This method utilizes oligonucleotide-conjugated polyclonal antibodies and quantifies antibody-antigen binding affinities by quantitative reverse transcription-PCR (RT-PCR). Results showed the assay can rapidly detect H3N2 IAVs directly from nasal wash or nasal swab samples collected from laboratory-challenged animals or during influenza surveillance at county fairs. In addition, polyPLA can accurately separate the viruses at two contemporary swine IAV antigenic clusters (H3N2 swine IAV-α and H3N2 swine IAV-ß) with a sensitivity of 84.9% and a specificity of 100.0%. The polyPLA can be routinely used in surveillance programs to detect antigenic variants of influenza viruses and to select vaccine strains for use in controlling and preventing disease in swine. PMID:28077698

  15. Pathogenicity and transmission in pigs of the novel A(H3N2)v influenza virus isolated from humans and characterization of swine H3N2 viruses isolated in 2010-2011

    USDA-ARS?s Scientific Manuscript database

    Swine influenza virus (SIV) H3N2 with triple reassorted internal genes (TRIG) has been enzootic in U.S. since 1998. Transmission of the 2009 pandemic H1N1 (pH1N1) virus to pigs in the U.S. was followed by reassortment with endemic SIV, resulting in reassorted viruses that include novel H3N2 genotype...

  16. Detection of Antigenic Variants of Subtype H3 Swine Influenza A Viruses from Clinical Samples.

    PubMed

    Martin, Brigitte E; Bowman, Andrew S; Li, Lei; Nolting, Jacqueline M; Smith, David R; Hanson, Larry A; Wan, Xiu-Feng

    2017-04-01

    A large population of genetically and antigenically diverse influenza A viruses (IAVs) are circulating among the swine population, playing an important role in influenza ecology. Swine IAVs not only cause outbreaks among swine but also can be transmitted to humans, causing sporadic infections and even pandemic outbreaks. Antigenic characterizations of swine IAVs are key to understanding the natural history of these viruses in swine and to selecting strains for effective vaccines. However, influenza outbreaks generally spread rapidly among swine, and the conventional methods for antigenic characterization require virus propagation, a time-consuming process that can significantly reduce the effectiveness of vaccination programs. We developed and validated a rapid, sensitive, and robust method, the polyclonal serum-based proximity ligation assay (polyPLA), to identify antigenic variants of subtype H3N2 swine IAVs. This method utilizes oligonucleotide-conjugated polyclonal antibodies and quantifies antibody-antigen binding affinities by quantitative reverse transcription-PCR (RT-PCR). Results showed the assay can rapidly detect H3N2 IAVs directly from nasal wash or nasal swab samples collected from laboratory-challenged animals or during influenza surveillance at county fairs. In addition, polyPLA can accurately separate the viruses at two contemporary swine IAV antigenic clusters (H3N2 swine IAV-α and H3N2 swine IAV-ß) with a sensitivity of 84.9% and a specificity of 100.0%. The polyPLA can be routinely used in surveillance programs to detect antigenic variants of influenza viruses and to select vaccine strains for use in controlling and preventing disease in swine. Copyright © 2017 American Society for Microbiology.

  17. Molecular evidence for interspecies transmission of H3N2pM/H3N2v influenza A viruses at an Ohio agricultural fair, July 2012

    PubMed Central

    Bowman, Andrew S; Sreevatsan, Srinand; Killian, Mary L; Page, Shannon L; Nelson, Sarah W; Nolting, Jacqueline M; Cardona, Carol; Slemons, Richard D

    2012-01-01

    Evidence accumulating in 2011–2012 indicates that there is significant intra- and inter-species transmission of influenza A viruses at agricultural fairs, which has renewed interest in this unique human/swine interface. Six human cases of influenza A (H3N2) variant (H3N2v) virus infections were epidemiologically linked to swine exposure at fairs in the United States in 2011. In 2012, the number of H3N2v cases in the Midwest had exceeded 300 from early July to September, 2012. Prospective influenza A virus surveillance among pigs at Ohio fairs resulted in the detection of H3N2pM (H3N2 influenza A viruses containing the matrix (M) gene from the influenza A (H1N1) pdm09 virus). These H3N2pM viruses were temporally and spatially linked to several human H3N2v cases. Complete genomic analyses of these H3N2pM isolates demonstrated >99% nucleotide similarity to the H3N2v isolates recovered from human cases. Actions to mitigate the bidirectional interspecies transmission of influenza A virus between people and animals at agricultural fairs may be warranted. PMID:26038404

  18. Outbreak of Influenza A(H3N2) Variant Virus Infections Among Persons Attending Agricultural Fairs Housing Infected Swine - Michigan and Ohio, July-August 2016.

    PubMed

    Schicker, Rebekah S; Rossow, John; Eckel, Seth; Fisher, Nicolas; Bidol, Sally; Tatham, Lilith; Matthews-Greer, Janice; Sohner, Kevin; Bowman, Andrew S; Avrill, James; Forshey, Tony; Blanton, Lenee; Davis, C Todd; Schiltz, John; Skorupski, Susan; Berman, LaShondra; Jang, Yunho; Bresee, Joseph S; Lindstrom, Stephen; Trock, Susan C; Wentworth, David; Fry, Alicia M; de Fijter, Sietske; Signs, Kimberly; DiOrio, Mary; Olsen, Sonja J; Biggerstaff, Matthew

    2016-10-28

    On August 3, 2016, the Ohio Department of Health Laboratory reported to CDC that a respiratory specimen collected on July 28 from a male aged 13 years who attended an agricultural fair in Ohio during July 22-29, 2016, and subsequently developed a respiratory illness, tested positive by real-time reverse transcription-polymerase chain reaction (rRT-PCR) for influenza A(H3N2) variant* (H3N2v). The respiratory specimen was collected as part of routine influenza surveillance activities. The next day, CDC was notified of a child aged 9 years who was a swine exhibitor at an agricultural fair in Michigan who became ill on July 29, 2016, and tested positive for H3N2v virus at the Michigan Department of Health and Human Services Laboratory. Investigations by Michigan and Ohio health authorities identified 18 human infections linked to swine exhibits at agricultural fairs. To minimize transmission of influenza viruses from infected swine to visitors, agricultural fair organizers should consider prevention measures such as shortening the time swine are on the fairgrounds, isolating ill swine, maintaining a veterinarian on call, providing handwashing stations, and prohibiting food and beverages in animal barns. Persons at high risk for influenza-associated complications should be discouraged from entering swine barns.

  19. Outbreak of variant influenza A(H3N2) virus in the United States.

    PubMed

    Jhung, Michael A; Epperson, Scott; Biggerstaff, Matthew; Allen, Donna; Balish, Amanda; Barnes, Nathelia; Beaudoin, Amanda; Berman, Lashondra; Bidol, Sally; Blanton, Lenee; Blythe, David; Brammer, Lynnette; D'Mello, Tiffany; Danila, Richard; Davis, William; de Fijter, Sietske; Diorio, Mary; Durand, Lizette O; Emery, Shannon; Fowler, Brian; Garten, Rebecca; Grant, Yoran; Greenbaum, Adena; Gubareva, Larisa; Havers, Fiona; Haupt, Thomas; House, Jennifer; Ibrahim, Sherif; Jiang, Victoria; Jain, Seema; Jernigan, Daniel; Kazmierczak, James; Klimov, Alexander; Lindstrom, Stephen; Longenberger, Allison; Lucas, Paul; Lynfield, Ruth; McMorrow, Meredith; Moll, Maria; Morin, Craig; Ostroff, Stephen; Page, Shannon L; Park, Sarah Y; Peters, Susan; Quinn, Celia; Reed, Carrie; Richards, Shawn; Scheftel, Joni; Simwale, Owen; Shu, Bo; Soyemi, Kenneth; Stauffer, Jill; Steffens, Craig; Su, Su; Torso, Lauren; Uyeki, Timothy M; Vetter, Sara; Villanueva, Julie; Wong, Karen K; Shaw, Michael; Bresee, Joseph S; Cox, Nancy; Finelli, Lyn

    2013-12-01

    Variant influenza virus infections are rare but may have pandemic potential if person-to-person transmission is efficient. We describe the epidemiology of a multistate outbreak of an influenza A(H3N2) variant virus (H3N2v) first identified in 2011. We identified laboratory-confirmed cases of H3N2v and used a standard case report form to characterize illness and exposures. We considered illness to result from person-to-person H3N2v transmission if swine contact was not identified within 4 days prior to illness onset. From 9 July to 7 September 2012, we identified 306 cases of H3N2v in 10 states. The median age of all patients was 7 years. Commonly reported signs and symptoms included fever (98%), cough (85%), and fatigue (83%). Sixteen patients (5.2%) were hospitalized, and 1 fatal case was identified. The majority of those infected reported agricultural fair attendance (93%) and/or contact with swine (95%) prior to illness. We identified 15 cases of possible person-to-person transmission of H3N2v. Viruses recovered from patients were 93%-100% identical and similar to viruses recovered from previous cases of H3N2v. All H3N2v viruses examined were susceptible to oseltamivir and zanamivir and resistant to adamantane antiviral medications. In a large outbreak of variant influenza, the majority of infected persons reported exposures, suggesting that swine contact at an agricultural fair was a risk for H3N2v infection. We identified limited person-to-person H3N2v virus transmission, but found no evidence of efficient or sustained person-to-person transmission. Fair managers and attendees should be aware of the risk of swine-to-human transmission of influenza viruses in these settings.

  20. Swine Influenza Virus PA and Neuraminidase Gene Reassortment into Human H1N1 Influenza Virus Is Associated with an Altered Pathogenic Phenotype Linked to Increased MIP-2 Expression.

    PubMed

    Dlugolenski, Daniel; Jones, Les; Howerth, Elizabeth; Wentworth, David; Tompkins, S Mark; Tripp, Ralph A

    2015-05-01

    Swine are susceptible to infection by both avian and human influenza viruses, and this feature is thought to contribute to novel reassortant influenza viruses. In this study, the influenza virus reassortment rate in swine and human cells was determined. Coinfection of swine cells with 2009 pandemic H1N1 virus (huH1N1) and an endemic swine H1N2 (A/swine/Illinois/02860/09) virus (swH1N2) resulted in a 23% reassortment rate that was independent of α2,3- or α2,6-sialic acid distribution on the cells. The reassortants had altered pathogenic phenotypes linked to introduction of the swine virus PA and neuraminidase (NA) into huH1N1. In mice, the huH1N1 PA and NA mediated increased MIP-2 expression early postinfection, resulting in substantial pulmonary neutrophilia with enhanced lung pathology and disease. The findings support the notion that swine are a mixing vessel for influenza virus reassortants independent of sialic acid distribution. These results show the potential for continued reassortment of the 2009 pandemic H1N1 virus with endemic swine viruses and for reassortants to have increased pathogenicity linked to the swine virus NA and PA genes which are associated with increased pulmonary neutrophil trafficking that is related to MIP-2 expression. Influenza A viruses can change rapidly via reassortment to create a novel virus, and reassortment can result in possible pandemics. Reassortments among subtypes from avian and human viruses led to the 1957 (H2N2 subtype) and 1968 (H3N2 subtype) human influenza pandemics. Recent analyses of circulating isolates have shown that multiple genes can be recombined from human, avian, and swine influenza viruses, leading to triple reassortants. Understanding the factors that can affect influenza A virus reassortment is needed for the establishment of disease intervention strategies that may reduce or preclude pandemics. The findings from this study show that swine cells provide a mixing vessel for influenza virus reassortment

  1. Swine Influenza Virus PA and Neuraminidase Gene Reassortment into Human H1N1 Influenza Virus Is Associated with an Altered Pathogenic Phenotype Linked to Increased MIP-2 Expression

    PubMed Central

    Dlugolenski, Daniel; Jones, Les; Howerth, Elizabeth; Wentworth, David; Tompkins, S. Mark

    2015-01-01

    ABSTRACT Swine are susceptible to infection by both avian and human influenza viruses, and this feature is thought to contribute to novel reassortant influenza viruses. In this study, the influenza virus reassortment rate in swine and human cells was determined. Coinfection of swine cells with 2009 pandemic H1N1 virus (huH1N1) and an endemic swine H1N2 (A/swine/Illinois/02860/09) virus (swH1N2) resulted in a 23% reassortment rate that was independent of α2,3- or α2,6-sialic acid distribution on the cells. The reassortants had altered pathogenic phenotypes linked to introduction of the swine virus PA and neuraminidase (NA) into huH1N1. In mice, the huH1N1 PA and NA mediated increased MIP-2 expression early postinfection, resulting in substantial pulmonary neutrophilia with enhanced lung pathology and disease. The findings support the notion that swine are a mixing vessel for influenza virus reassortants independent of sialic acid distribution. These results show the potential for continued reassortment of the 2009 pandemic H1N1 virus with endemic swine viruses and for reassortants to have increased pathogenicity linked to the swine virus NA and PA genes which are associated with increased pulmonary neutrophil trafficking that is related to MIP-2 expression. IMPORTANCE Influenza A viruses can change rapidly via reassortment to create a novel virus, and reassortment can result in possible pandemics. Reassortments among subtypes from avian and human viruses led to the 1957 (H2N2 subtype) and 1968 (H3N2 subtype) human influenza pandemics. Recent analyses of circulating isolates have shown that multiple genes can be recombined from human, avian, and swine influenza viruses, leading to triple reassortants. Understanding the factors that can affect influenza A virus reassortment is needed for the establishment of disease intervention strategies that may reduce or preclude pandemics. The findings from this study show that swine cells provide a mixing vessel for influenza

  2. H1N1 influenza (Swine flu)

    MedlinePlus

    Swine flu; H1N1 type A influenza ... The H1N1 virus is now considered a regular flu virus. It is one of the three viruses included in the regular (seasonal) flu vaccine . You cannot get H1N1 flu virus from ...

  3. Experimental infection with H1N1 European swine influenza virus protects pigs from an infection with the 2009 pandemic H1N1 human influenza virus.

    PubMed

    Busquets, Núria; Segalés, Joaquim; Córdoba, Lorena; Mussá, Tufaria; Crisci, Elisa; Martín-Valls, Gerard E; Simon-Grifé, Meritxell; Pérez-Simó, Marta; Pérez-Maíllo, Monica; Núñez, Jose I; Abad, Francesc X; Fraile, Lorenzo; Pina, Sonia; Majó, Natalia; Bensaid, Albert; Domingo, Mariano; Montoya, María

    2010-01-01

    The recent pandemic caused by human influenza virus A(H1N1) 2009 contains ancestral gene segments from North American and Eurasian swine lineages as well as from avian and human influenza lineages. The emergence of this A(H1N1) 2009 poses a potential global threat for human health and the fact that it can infect other species, like pigs, favours a possible encounter with other influenza viruses circulating in swine herds. In Europe, H1N1, H1N2 and H3N2 subtypes of swine influenza virus currently have a high prevalence in commercial farms. To better assess the risk posed by the A(H1N1) 2009 in the actual situation of swine farms, we sought to analyze whether a previous infection with a circulating European avian-like swine A/Swine/Spain/53207/2004 (H1N1) influenza virus (hereafter referred to as SwH1N1) generated or not cross-protective immunity against a subsequent infection with the new human pandemic A/Catalonia/63/2009 (H1N1) influenza virus (hereafter referred to as pH1N1) 21 days apart. Pigs infected only with pH1N1 had mild to moderate pathological findings, consisting on broncho-interstitial pneumonia. However, pigs inoculated with SwH1N1 virus and subsequently infected with pH1N1 had very mild lung lesions, apparently attributed to the remaining lesions caused by SwH1N1 infection. These later pigs also exhibited boosted levels of specific antibodies. Finally, animals firstly infected with SwH1N1 virus and latter infected with pH1N1 exhibited undetectable viral RNA load in nasal swabs and lungs after challenge with pH1N1, indicating a cross-protective effect between both strains. © INRA, EDP Sciences, 2010.

  4. Pathogenicity and Transmission in Pigs of the Novel A(H3N2)v Influenza Virus Isolated from Humans and Characterization of Swine H3N2 Viruses Isolated in 2010-2011

    PubMed Central

    Kitikoon, Pravina; Gauger, Phillip C.; Schlink, Sarah N.; Bayles, Darrell O.; Gramer, Marie R.; Darnell, Daniel; Webby, Richard J.; Lager, Kelly M.; Swenson, Sabrina L.; Klimov, Alexander

    2012-01-01

    Swine influenza virus (SIV) H3N2 with triple reassorted internal genes (TRIG) has been enzootic in Unites States since 1998. Transmission of the 2009 pandemic H1N1 (pH1N1) virus to pigs in the United States was followed by reassortment with endemic SIV, resulting in reassorted viruses that include novel H3N2 genotypes (rH3N2p). Between July and December 2011, 12 cases of human infections with swine-lineage H3N2 viruses containing the pandemic matrix (pM) gene [A(H3N2)v] were detected. Whole-genome analysis of H3N2 viruses isolated from pigs from 2009 to 2011 sequenced in this study and other available H3N2 sequences showed six different rH3N2p genotypes present in the U.S. swine population since 2009. The presence of the pM gene was a common feature among all rH3N2p genotypes, but no specific genotype appeared to predominate in the swine population. We compared the pathogenic, transmission, genetic, and antigenic properties of a human A(H3N2)v isolate and two swine H3N2 isolates, H3N2-TRIG and rH3N2p. Our in vivo study detected no increased virulence in A(H3N2)v or rH3N2p viruses compared to endemic H3N2-TRIG virus. Antibodies to cluster IV H3N2-TRIG and rH3N2p viruses had reduced cross-reactivity to A(H3N2)v compared to other cluster IV H3N2-TRIG and rH3N2p viruses. Genetic analysis of the hemagglutinin gene indicated that although rH3N2p and A(H3N2)v are related to cluster IV of H3N2-TRIG, some recent rH3N2p isolates appeared to be forming a separate cluster along with the human isolates of A(H3N2)v. Continued monitoring of these H3N2 viruses is necessary to evaluate the evolution and potential loss of population immunity in swine and humans. PMID:22491461

  5. Pathogenicity and transmission in pigs of the novel A(H3N2)v influenza virus isolated from humans and characterization of swine H3N2 viruses isolated in 2010-2011.

    PubMed

    Kitikoon, Pravina; Vincent, Amy L; Gauger, Phillip C; Schlink, Sarah N; Bayles, Darrell O; Gramer, Marie R; Darnell, Daniel; Webby, Richard J; Lager, Kelly M; Swenson, Sabrina L; Klimov, Alexander

    2012-06-01

    Swine influenza virus (SIV) H3N2 with triple reassorted internal genes (TRIG) has been enzootic in Unites States since 1998. Transmission of the 2009 pandemic H1N1 (pH1N1) virus to pigs in the United States was followed by reassortment with endemic SIV, resulting in reassorted viruses that include novel H3N2 genotypes (rH3N2p). Between July and December 2011, 12 cases of human infections with swine-lineage H3N2 viruses containing the pandemic matrix (pM) gene [A(H3N2)v] were detected. Whole-genome analysis of H3N2 viruses isolated from pigs from 2009 to 2011 sequenced in this study and other available H3N2 sequences showed six different rH3N2p genotypes present in the U.S. swine population since 2009. The presence of the pM gene was a common feature among all rH3N2p genotypes, but no specific genotype appeared to predominate in the swine population. We compared the pathogenic, transmission, genetic, and antigenic properties of a human A(H3N2)v isolate and two swine H3N2 isolates, H3N2-TRIG and rH3N2p. Our in vivo study detected no increased virulence in A(H3N2)v or rH3N2p viruses compared to endemic H3N2-TRIG virus. Antibodies to cluster IV H3N2-TRIG and rH3N2p viruses had reduced cross-reactivity to A(H3N2)v compared to other cluster IV H3N2-TRIG and rH3N2p viruses. Genetic analysis of the hemagglutinin gene indicated that although rH3N2p and A(H3N2)v are related to cluster IV of H3N2-TRIG, some recent rH3N2p isolates appeared to be forming a separate cluster along with the human isolates of A(H3N2)v. Continued monitoring of these H3N2 viruses is necessary to evaluate the evolution and potential loss of population immunity in swine and humans.

  6. Novel triple-reassortant H1N1 swine influenza viruses in pigs in Tianjin, Northern China.

    PubMed

    Sun, Ying-Feng; Wang, Xiu-Hui; Li, Xiu-Li; Zhang, Li; Li, Hai-Hua; Lu, Chao; Yang, Chun-Lei; Feng, Jing; Han, Wei; Ren, Wei-Ke; Tian, Xiang-Xue; Tong, Guang-Zhi; Wen, Feng; Li, Ze-Jun; Gong, Xiao-Qian; Liu, Xiao-Min; Ruan, Bao-Yang; Yan, Ming-Hua; Yu, Hai

    2016-02-01

    Pigs are susceptible to both human and avian influenza viruses and therefore have been proposed to be mixing vessels for the generation of pandemic influenza viruses through reassortment. In this study, for the first time, we report the isolation and genetic analyses of three novel triple-reassortant H1N1 swine influenza viruses from pigs in Tianjin, Northern China. Phylogenetic analysis showed that these novel viruses contained genes from the 2009 pandemic H1N1 (PB2, PB1, PA and NP), Eurasian swine (HA, NA and M) and triple-reassortant swine (NS) lineages. This indicated that the reassortment among the 2009 pandemic H1N1, Eurasian swine and triple-reassortant swine influenza viruses had taken place in pigs in Tianjin and resulted in the generation of new viruses. Furthermore, three human-like H1N1, two classical swine H1N1 and two Eurasian swine H1N1 viruses were also isolated during the swine influenza virus surveillance from 2009 to 2013, which indicated that multiple genetic lineages of swine H1N1 viruses were co-circulating in the swine population in Tianjin, China. The emergence of novel triple-reassortant H1N1 swine influenza viruses may be a potential threat to human health and emphasizes the importance of further continuous surveillance. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Genetic characterization of H1N2 swine influenza virus isolated in China and its pathogenesis and inflammatory responses in mice.

    PubMed

    Zhang, Yan; Wang, Nan; Cao, Jiyue; Chen, Huanchun; Jin, Meilin; Zhou, Hongbo

    2013-09-01

    In 2009, two H1N2 influenza viruses were isolated from trachea swabs of pigs in Hubei in China. We compared these sequences with the other 18 complete genome sequences of swine H1N2 isolates from China during 2004 to 2010 and undertook extensive analysis of their evolutionary patterns. Six different genotypes - two reassortants between triple reassortant (TR) H3N2 and classical swine (CS) H1N1 virus, three reassortants between TR H1N2, Eurasian avian-like H1N1 swine virus and H9N2 swine virus, and one reassortant between H1N1, H3N2 human virus and CS H1N1 virus - were observed in these 20 swine H1N2 isolates. The TR H1N2 swine virus is the predominant genotype, and the two Hubei H1N2 isolates were located in this cluster. We also used a mouse model to examine the pathogenesis and inflammatory responses of the two isolates. The isolates replicated efficiently in the lung, and exhibited a strong inflammatory response, serious pathological changes and mortality in infected mice. Given the role that swine can play as putative "genetic mixing vessels" and the observed transmission of TR H1N2 in ferrets, H1N2 influenza surveillance in pigs should be increased to minimize the potential threat to public health.

  8. Protection of guinea pigs by vaccination with a recombinant swinepox virus co-expressing HA1 genes of swine H1N1 and H3N2 influenza viruses.

    PubMed

    Xu, Jiarong; Yang, Deji; Huang, Dongyan; Xu, Jiaping; Liu, Shichao; Lin, Huixing; Zhu, Haodan; Liu, Bao; Lu, Chengping

    2013-03-01

    Swine influenza (SI) is an acute respiratory infectious disease of swine caused by swine influenza virus (SIV). SIV is not only an important respiratory pathogen in pigs but also a potent threat to human health. Here, we report the construction of a recombinant swinepox virus (rSPV/H3-2A-H1) co-expressing hemagglutinin (HA1) of SIV subtypes H1N1 and H3N2. Immune responses and protection efficacy of the rSPV/H3-2A-H1 were evaluated in guinea pigs. Inoculation of rSPV/H3-2A-H1 yielded neutralizing antibodies against SIV H1N1 and H3N2. The IFN-γ and IL-4 concentrations in the supernatant of lymphocytes stimulated with purified SIV HA1 antigen were significantly higher (P < 0.01) than those of the control groups. Complete protection of guinea pigs against SIV H1N1 or H3N2 challenge was observed. No SIV shedding was detected from guinea pigs vaccinated with rSPV/H3-2A-H1 after challenge. Most importantly, the guinea pigs immunized with rSPV/H3-2A-H1 did not show gross and micrographic lung lesions. However, the control guinea pigs experienced distinct gross and micrographic lung lesions at 7 days post-challenge. Our data suggest that the recombinant swinepox virus encoding HA1 of SIV H1N1 and H3N2 might serve as a promising candidate vaccine for protection against SIV H1N1 and H3N2 infections.

  9. Outbreak of Variant Influenza A(H3N2) Virus in the United States

    PubMed Central

    Jhung, Michael A.; Epperson, Scott; Biggerstaff, Matthew; Allen, Donna; Balish, Amanda; Barnes, Nathelia; Beaudoin, Amanda; Berman, LaShondra; Bidol, Sally; Blanton, Lenee; Blythe, David; Brammer, Lynnette; D’Mello, Tiffany; Danila, Richard; Davis, William; de Fijter, Sietske; DiOrio, Mary; Durand, Lizette O.; Emery, Shannon; Fowler, Brian; Garten, Rebecca; Grant, Yoran; Greenbaum, Adena; Gubareva, Larisa; Havers, Fiona; Haupt, Thomas; House, Jennifer; Ibrahim, Sherif; Jiang, Victoria; Jain, Seema; Jernigan, Daniel; Kazmierczak, James; Klimov, Alexander; Lindstrom, Stephen; Longenberger, Allison; Lucas, Paul; Lynfield, Ruth; McMorrow, Meredith; Moll, Maria; Morin, Craig; Ostroff, Stephen; Page, Shannon L.; Park, Sarah Y.; Peters, Susan; Quinn, Celia; Reed, Carrie; Richards, Shawn; Scheftel, Joni; Simwale, Owen; Shu, Bo; Soyemi, Kenneth; Stauffer, Jill; Steffens, Craig; Su, Su; Torso, Lauren; Uyeki, Timothy M.; Vetter, Sara; Villanueva, Julie; Wong, Karen K.; Shaw, Michael; Bresee, Joseph S.; Cox, Nancy; Finelli, Lyn

    2017-01-01

    Background Variant influenza virus infections are rare but may have pandemic potential if person-to-person transmission is efficient. We describe the epidemiology of a multistate outbreak of an influenza A(H3N2) variant virus (H3N2v) first identified in 2011. Methods We identified laboratory-confirmed cases of H3N2v and used a standard case report form to characterize illness and exposures. We considered illness to result from person-to-person H3N2v transmission if swine contact was not identified within 4 days prior to illness onset. Results From 9 July to 7 September 2012, we identified 306 cases of H3N2v in 10 states. The median age of all patients was 7 years. Commonly reported signs and symptoms included fever (98%), cough (85%), and fatigue (83%). Sixteen patients (5.2%) were hospitalized, and 1 fatal case was identified. The majority of those infected reported agricultural fair attendance (93%) and/or contact with swine (95%) prior to illness. We identified 15 cases of possible person-to-person transmission of H3N2v. Viruses recovered from patients were 93%–100% identical and similar to viruses recovered from previous cases of H3N2v. All H3N2v viruses examined were susceptible to oseltamivir and zanamivir and resistant to adamantane antiviral medications. Conclusions In a large outbreak of variant influenza, the majority of infected persons reported exposures, suggesting that swine contact at an agricultural fair was a risk for H3N2v infection. We identified limited person-to-person H3N2v virus transmission, but found no evidence of efficient or sustained person-to-person transmission. Fair managers and attendees should be aware of the risk of swine-to-human transmission of influenza viruses in these settings. PMID:24065322

  10. Complete genome sequence of a novel influenza A H1N2 virus circulating in swine from Central Bajio region, Mexico.

    PubMed

    Sánchez-Betancourt, J I; Cervantes-Torres, J B; Saavedra-Montañez, M; Segura-Velázquez, R A

    2017-12-01

    The aim of this study was to perform the complete genome sequence of a swine influenza A H1N2 virus strain isolated from a pig in Guanajuato, México (A/swine/Mexico/GtoDMZC01/2014) and to report its seroprevalence in 86 counties at the Central Bajio zone. To understand the evolutionary dynamics of the isolate, we undertook a phylogenetic analysis of the eight gene segments. These data revealed that the isolated virus is a reassortant H1N2 subtype, as its genes are derived from human (HA, NP, PA) and swine (M, NA, PB1, PB2 and NS) influenza viruses. Pig serum samples were analysed by the hemagglutination inhibition test, using wild H1N2 and H3N2 strains (A/swine/México/Mex51/2010 [H3N2]) as antigen sources. Positive samples to the H1N2 subtype were processed using the field-isolated H1N1 subtype (A/swine/México/Ver37/2010 [H1N1]). Seroprevalence to the H1N2 subtype was 26.74% in the sampled counties, being Jalisco the state with highest seroprevalence to this subtype (35.30%). The results herein reported demonstrate that this new, previously unregistered influenza virus subtype in México that shows internal genes from other swine viral subtypes isolated in the past 5 years, along with human virus-originated genes, is widely distributed in this area of the country. © 2017 Blackwell Verlag GmbH.

  11. Identification of swine H1N2/pandemic H1N1 reassortant influenza virus in pigs, United States.

    PubMed

    Ali, Ahmed; Khatri, Mahesh; Wang, Leyi; Saif, Yehia M; Lee, Chang-Won

    2012-07-06

    In October and November 2010, novel H1N2 reassortant influenza viruses were identified from pigs showing mild respiratory signs that included cough and depression. Sequence and phylogenetic analysis showed that the novel H1N2 reassortants possesses HA and NA genes derived from recent H1N2 swine isolates similar to those isolated from Midwest. Compared to the majority of reported reassortants, both viruses preserved human-like host restrictive and putative antigenic sites in their HA and NA genes. The four internal genes, PB2, PB1, PA, and NS were similar to the contemporary swine triple reassortant viruses' internal genes (TRIG). Interestingly, NP and M genes of the novel reassortants were derived from the 2009 pandemic H1N1. The NP and M proteins of the two isolates demonstrated one (E16G) and four (G34A, D53E, I109T, and V313I) amino acid changes in the M2 and NP proteins, respectively. Similar amino acid changes were also noticed upon incorporation of the 2009 pandemic H1N1 NP in other reassortant viruses reported in the U.S. Thus the role of those amino acids in relation to host adaptation need to be further investigated. The reassortments of pandemic H1N1 with swine influenza viruses and the potential of interspecies transmission of these reassortants from swine to other species including human indicate the importance of systematic surveillance of swine population to determine the origin, the prevalence of similar reassortants in the U.S. and their impact on both swine production and public health. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. [Phylogenetic analysis of human/swine/avian gene reassortant H1N2 influenza A virus isolated from a pig in China].

    PubMed

    Chen, Yixiang; Meng, Xueqiong; Liu, Qi; Huang, Xia; Huang, Shengbin; Liu, Cuiquan; Shi, Kaichuang; Guo, Jiangang; Chen, Fangfang; Hu, Liping

    2008-04-01

    Our aim in this study was to determine the genetic characterization and probable origin of the H1N2 swine influenza virus (A/Swine/Guangxi/13/2006) (Sw/GX/13/06) from lung tissue of a pig in Guangxi province, China. Eight genes of Sw/GX/13/06 were cloned and genetically analyzed. The hemagglutinin (HA), nucleoprotein (NP), matrix (M) and non-structural (NS) genes of Sw/GX/13/06 were most closely related to genes from the classical swine H1N1 influenza virus lineage. The neuraminidase (NA) and PB1 genes were most closely related to the corresponding genes from the human influenza H3N2 virus lineage. The remaining two genes PA and PB2 polymerase genes were most closely related to the genes from avian influenza virus lineage. Phylogenetic analyses revealed that Sw/GX/13/06 was a human/swine/avian H1N2 virus, and closely related to H1N2 viruses isolated from pigs in United States (1999-2001) and Korea (2002). To our knowledge, Sw/GX/13/06 was the first triple-reassortant H1N2 influenza A virus isolated from a pig in China. Whether the Sw/GX/13/06 has a potential threat to breeding farm and human health remains to be further investigated.

  13. Reassortant H1N1 influenza virus vaccines protect pigs against pandemic H1N1 influenza virus and H1N2 swine influenza virus challenge.

    PubMed

    Yang, Huanliang; Chen, Yan; Shi, Jianzhong; Guo, Jing; Xin, Xiaoguang; Zhang, Jian; Wang, Dayan; Shu, Yuelong; Qiao, Chuanling; Chen, Hualan

    2011-09-28

    Influenza A (H1N1) virus has caused human influenza outbreaks in a worldwide pandemic since April 2009. Pigs have been found to be susceptible to this influenza virus under experimental and natural conditions, raising concern about their potential role in the pandemic spread of the virus. In this study, we generated a high-growth reassortant virus (SC/PR8) that contains the hemagglutinin (HA) and neuraminidase (NA) genes from a novel H1N1 isolate, A/Sichuan/1/2009 (SC/09), and six internal genes from A/Puerto Rico/8/34 (PR8) virus, by genetic reassortment. The immunogenicity and protective efficacy of this reassortant virus were evaluated at different doses in a challenge model using a homologous SC/09 or heterologous A/Swine/Guangdong/1/06(H1N2) virus (GD/06). Two doses of SC/PR8 virus vaccine elicited high-titer serum hemagglutination inhibiting (HI) antibodies specific for the 2009 H1N1 virus and conferred complete protection against challenge with either SC/09 or GD/06 virus, with reduced lung lesions and viral shedding in vaccine-inoculated animals compared with non-vaccinated control animals. These results indicated for the first time that a high-growth SC/PR8 reassortant H1N1 virus exhibits properties that are desirable to be a promising vaccine candidate for use in swine in the event of a pandemic H1N1 influenza. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Potency of an inactivated influenza vaccine prepared from A/duck/Hokkaido/162/2013 (H2N1) against a challenge with A/swine/Missouri/2124514/2006 (H2N3) in mice

    PubMed Central

    SUZUKI, Mizuho; OKAMATSU, Masatoshi; HIONO, Takahiro; MATSUNO, Keita; SAKODA, Yoshihiro

    2017-01-01

    H2N2 influenza virus caused a pandemic starting in 1957 but has not been detected in humans since 1968. Thus, most people are immunologically naive to viruses of the H2 subtype. In contrast, H2 influenza viruses are continually isolated from wild birds, and H2N3 viruses were isolated from pigs in 2006. H2 influenza viruses could cause a pandemic if re-introduced into humans. In the present study, a vaccine against H2 influenza was prepared as an effective control measure against a future human pandemic. A/duck/Hokkaido/162/2013 (H2N1), which showed broad antigenic cross-reactivity, was selected from the candidate H2 influenza viruses recently isolated from wild birds in Asian countries. Sufficient neutralizing antibodies against homologous and heterologous viruses were induced in mice after two subcutaneous injections of the inactivated whole virus particle vaccine. The inactivated vaccine induced protective immunity sufficient to reduce the impact of challenges with A/swine/Missouri/2124514/2006 (H2N3). This study demonstrates that the inactivated whole virus particle vaccine prepared from an influenza virus library would be useful against a future H2 influenza pandemic. PMID:28993601

  15. Substitutions near the hemagglutinin receptor-binding site determine the antigenic evolution of influenza A H3N2 viruses in U.S. swine.

    PubMed

    Lewis, Nicola S; Anderson, Tavis K; Kitikoon, Pravina; Skepner, Eugene; Burke, David F; Vincent, Amy L

    2014-05-01

    Swine influenza A virus is an endemic and economically important pathogen in pigs, with the potential to infect other host species. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major component in swine influenza A vaccines. However, as a result of antigenic drift, vaccine strains must be regularly updated to reflect currently circulating strains. Characterizing the cross-reactivity between strains in pigs and seasonal influenza virus strains in humans is also important in assessing the relative risk of interspecies transmission of viruses from one host population to the other. Hemagglutination inhibition (HI) assay data for swine and human H3N2 viruses were used with antigenic cartography to quantify the antigenic differences among H3N2 viruses isolated from pigs in the United States from 1998 to 2013 and the relative cross-reactivity between these viruses and current human seasonal influenza A virus strains. Two primary antigenic clusters were found circulating in the pig population, but with enough diversity within and between the clusters to suggest updates in vaccine strains are needed. We identified single amino acid substitutions that are likely responsible for antigenic differences between the two primary antigenic clusters and between each antigenic cluster and outliers. The antigenic distance between current seasonal influenza virus H3 strains in humans and those endemic in swine suggests that population immunity may not prevent the introduction of human viruses into pigs, and possibly vice versa, reinforcing the need to monitor and prepare for potential incursions. Influenza A virus (IAV) is an important pathogen in pigs and humans. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major target of vaccines. However, vaccine strains must be updated to reflect current strains. Characterizing the differences between seasonal IAV in humans and swine IAV is important in

  16. Substitutions near the Hemagglutinin Receptor-Binding Site Determine the Antigenic Evolution of Influenza A H3N2 Viruses in U.S. Swine

    PubMed Central

    Lewis, Nicola S.; Anderson, Tavis K.; Kitikoon, Pravina; Skepner, Eugene; Burke, David F.

    2014-01-01

    ABSTRACT Swine influenza A virus is an endemic and economically important pathogen in pigs, with the potential to infect other host species. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major component in swine influenza A vaccines. However, as a result of antigenic drift, vaccine strains must be regularly updated to reflect currently circulating strains. Characterizing the cross-reactivity between strains in pigs and seasonal influenza virus strains in humans is also important in assessing the relative risk of interspecies transmission of viruses from one host population to the other. Hemagglutination inhibition (HI) assay data for swine and human H3N2 viruses were used with antigenic cartography to quantify the antigenic differences among H3N2 viruses isolated from pigs in the United States from 1998 to 2013 and the relative cross-reactivity between these viruses and current human seasonal influenza A virus strains. Two primary antigenic clusters were found circulating in the pig population, but with enough diversity within and between the clusters to suggest updates in vaccine strains are needed. We identified single amino acid substitutions that are likely responsible for antigenic differences between the two primary antigenic clusters and between each antigenic cluster and outliers. The antigenic distance between current seasonal influenza virus H3 strains in humans and those endemic in swine suggests that population immunity may not prevent the introduction of human viruses into pigs, and possibly vice versa, reinforcing the need to monitor and prepare for potential incursions. IMPORTANCE Influenza A virus (IAV) is an important pathogen in pigs and humans. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major target of vaccines. However, vaccine strains must be updated to reflect current strains. Characterizing the differences between seasonal IAV in humans and swine

  17. Vaccination with NS1-truncated H3N2 swine influenza virus primes T cells and confers cross-protection against an H1N1 heterosubtypic challenge in pigs

    USDA-ARS?s Scientific Manuscript database

    The diversity of contemporary swine influenza virus (SIV) strains impedes effective immunization of swine herds. Mucosally delivered, attenuated virus vaccines are one approach with potential to provide broad cross-protection. Reverse genetics-derived H3N2 SIV virus with truncated NS1 (NS1delta126 T...

  18. Continual re-introduction of human pandemic H1N1 influenza A viruses into US swine, 2009-2014

    USDA-ARS?s Scientific Manuscript database

    Human-to-swine transmission of pandemic H1N1 influenza viruses (pH1N1) increased the genetic diversity of influenza A viruses in swine (swIAVs) globally and is linked to the emergence of new pandemic threats, including H3N2v variants. Through phylogenetic analysis of contemporary swIAVs in the Unit...

  19. The origin of the PB1 segment of swine influenza A virus subtype H1N2 determines viral pathogenicity in mice

    PubMed Central

    Metreveli, Giorgi; Gao, Qinshan; Mena, Nacho; Schmolke, Mirco; Berg, Mikael; Albrecht, Randy A.; García-Sastre, Adolfo

    2017-01-01

    Swine appear to be a key species in the generation of novel human influenza pandemics. Previous pandemic viruses are postulated to have evolved in swine by reassortment of avian, human, and swine influenza viruses. The human pandemic influenza viruses that emerged in 1957 and 1968 as well as swine viruses circulating since 1998 encode PB1 segments derived from avian influenza viruses. Here we investigate the possible role in viral replication and virulence of the PB1 gene segments present in two swine H1N2 influenza A viruses, A/swine/Sweden/1021/2009(H1N2) (sw 1021) and A/swine/Sweden/9706/2010(H1N2) (sw 9706), where the sw 1021 virus has shown to be more pathogenic in mice. By using reverse genetics, we swapped the PB1 genes of these two viruses. Similar to the sw 9706 virus, chimeric sw 1021 virus carrying the sw 9706 PB1 gene was not virulent in mice. In contrast, replacement of the PB1 gene of the sw 9706 virus by that from sw 1021 virus resulted in increased pathogenicity. Our study demonstrated that differences in virulence of swine influenza virus subtype H1N2 are attributed at least in part to the PB1 segment. PMID:24726997

  20. Carnosine markedly ameliorates H9N2 swine influenza virus-induced acute lung injury

    PubMed Central

    Wang, Cunlian; Zhang, Ruihua; Xu, Mingju; Liu, Baojian; Wei, Dong; Wang, Guohua; Tian, Shufei

    2015-01-01

    Oxidative stress injury is an important pathogenesis of influenza virus in critically ill patients. The present study investigated the efficacy of carnosine, an antioxidant and free radical scavenger, on a model of acute lung injury (ALI) induced by H9N2 swine influenza virus. Female specific-pathogen-free BALB/c mice were randomized into four groups and treated as follows: (1) H9N2 group, (2) mock control group, (3) H9N2+carnosine group and (4) carnosine control group. The H9N2 group mice were inoculated intranasally with A/Swine/Hebei/012/2008/ (H9N2) virus (100 μl) in allantoic fluid (AF), whilst mock-infected animals were intranasally inoculated with non-infectious AF. Carnosine [10 mg (kg body mass)− 1] was administered orally (100 μl) for 7 days consecutively. The survival rate, lung water content, TNF-α and IL-1β levels, lung histopathology, myeloperoxidase (MPO) activity, and Toll-like receptor (TLR)-4 levels were determined at 2, 4, 6, 8 and 14 days after inoculation. Carnosine treatment effectively decreased the mortality (43 versus 75 %, P < 0.05), significantly ameliorated pathological lesions in lungs and decreased the lung wet/dry mass ratio (P < 0.05). It also inhibited MPO activity, suppressed TNF-α and IL-1β release, decreased the H9N2 viral titre, and markedly inhibited levels of TLR-4 mRNA and protein in the lungs of infected mice (P < 0.05), which supported the use of carnosine for managing severe influenza cases. PMID:26233716

  1. Multiplex RT-PCR assay for differentiating European swine influenza virus subtypes H1N1, H1N2 and H3N2.

    PubMed

    Chiapponi, Chiara; Moreno, Ana; Barbieri, Ilaria; Merenda, Marianna; Foni, Emanuela

    2012-09-01

    In Europe, three major swine influenza viral (SIV) subtypes (H1N1, H1N2 and H3N2) have been isolated in pigs. Developing a test that is able to detect and identify the subtype of the circulating strain rapidly during an outbreak of respiratory disease in the pig population is of essential importance. This study describes two multiplex RT-PCRs which distinguish the haemagglutinin (HA) gene and the neuraminidase (NA) gene of the three major subtypes of SIV circulating in Europe. The HA PCR was able to identify the lineage (avian or human) of the HA of H1 subtypes. The analytical sensitivity of the test, considered to be unique, was assessed using three reference viruses. The detection limit corresponded to 1×10(-1) TCID(50)/200μl for avian-like H1N1, 1×10(0) TCID(50)/200μl for human-like H1N2 and 1×10(1) TCID(50)/200μl for H3N2 SIV. The multiplex RT-PCR was first carried out on a collection of 70 isolated viruses showing 100% specificity and then on clinical samples, from which viruses had previously been isolated, resulting in an 89% positive specificity of the viral subtype. Finally, the test was able to identify the viral subtype correctly in 56% of influenza A positive samples, from which SIV had not been isolated previously. It was also possible to identify mixed viral infections and the circulation of a reassortant strain before performing genomic studies. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Reassortment between Swine H3N2 and 2009 Pandemic H1N1 in the United States Resulted in Influenza A Viruses with Diverse Genetic Constellations with Variable Virulence in Pigs

    PubMed Central

    Rajão, Daniela S.; Walia, Rasna R.; Campbell, Brian; Gauger, Phillip C.; Janas-Martindale, Alicia; Killian, Mary Lea

    2016-01-01

    ABSTRACT Repeated spillovers of the H1N1 pandemic virus (H1N1pdm09) from humans to pigs resulted in substantial evolution of influenza A viruses infecting swine, contributing to the genetic and antigenic diversity of influenza A viruses (IAV) currently circulating in swine. The reassortment with endemic swine viruses and maintenance of some of the H1N1pdm09 internal genes resulted in the circulation of different genomic constellations in pigs. Here, we performed a whole-genome phylogenetic analysis of 368 IAV circulating in swine from 2009 to 2016 in the United States. We identified 44 different genotypes, with the most common genotype (32.33%) containing a clade IV-A HA gene, a 2002-lineage NA gene, an M-pdm09 gene, and remaining gene segments of triple reassortant internal gene (TRIG) origin. To understand how different genetic constellations may relate to viral fitness, we compared the pathogenesis and transmission in pigs of six representative genotypes. Although all six genotypes efficiently infected pigs, they resulted in different degrees of pathology and viral shedding. These results highlight the vast H3N2 genetic diversity circulating in U.S. swine after 2009. This diversity has important implications in the control of this disease by the swine industry, as well as a potential risk for public health if swine-adapted viruses with H1N1pdm09 genes have an increased risk to humans, as occurred in the 2011-2012 and 2016 human variant H3N2v cases associated with exhibition swine. IMPORTANCE People continue to spread the 2009 H1N1 pandemic (H1N1pdm09) IAV to pigs, allowing H1N1pdm09 to reassort with endemic swine IAV. In this study, we determined the 8 gene combinations of swine H3N2 IAV detected from 2009 to 2016. We identified 44 different genotypes of H3N2, the majority of which contained at least one H1N1pdm09 gene segment. We compared six representative genotypes of H3N2 in pigs. All six genotypes efficiently infected pigs, but they resulted in different

  3. Reassortment between Swine H3N2 and 2009 Pandemic H1N1 in the United States Resulted in Influenza A Viruses with Diverse Genetic Constellations with Variable Virulence in Pigs.

    PubMed

    Rajão, Daniela S; Walia, Rasna R; Campbell, Brian; Gauger, Phillip C; Janas-Martindale, Alicia; Killian, Mary Lea; Vincent, Amy L

    2017-02-15

    Repeated spillovers of the H1N1 pandemic virus (H1N1pdm09) from humans to pigs resulted in substantial evolution of influenza A viruses infecting swine, contributing to the genetic and antigenic diversity of influenza A viruses (IAV) currently circulating in swine. The reassortment with endemic swine viruses and maintenance of some of the H1N1pdm09 internal genes resulted in the circulation of different genomic constellations in pigs. Here, we performed a whole-genome phylogenetic analysis of 368 IAV circulating in swine from 2009 to 2016 in the United States. We identified 44 different genotypes, with the most common genotype (32.33%) containing a clade IV-A HA gene, a 2002-lineage NA gene, an M-pdm09 gene, and remaining gene segments of triple reassortant internal gene (TRIG) origin. To understand how different genetic constellations may relate to viral fitness, we compared the pathogenesis and transmission in pigs of six representative genotypes. Although all six genotypes efficiently infected pigs, they resulted in different degrees of pathology and viral shedding. These results highlight the vast H3N2 genetic diversity circulating in U.S. swine after 2009. This diversity has important implications in the control of this disease by the swine industry, as well as a potential risk for public health if swine-adapted viruses with H1N1pdm09 genes have an increased risk to humans, as occurred in the 2011-2012 and 2016 human variant H3N2v cases associated with exhibition swine. People continue to spread the 2009 H1N1 pandemic (H1N1pdm09) IAV to pigs, allowing H1N1pdm09 to reassort with endemic swine IAV. In this study, we determined the 8 gene combinations of swine H3N2 IAV detected from 2009 to 2016. We identified 44 different genotypes of H3N2, the majority of which contained at least one H1N1pdm09 gene segment. We compared six representative genotypes of H3N2 in pigs. All six genotypes efficiently infected pigs, but they resulted in different degrees of lung damage

  4. PB1-F2 Protein Does Not Impact the Virulence of Triple-Reassortant H3N2 Swine Influenza Virus in Pigs but Alters Pathogenicity and Transmission in Turkeys.

    PubMed

    Deventhiran, Jagadeeswaran; Kumar, Sandeep R P; Raghunath, Shobana; Leroith, Tanya; Elankumaran, Subbiah

    2016-01-01

    PB1-F2 protein, the 11th influenza A virus (IAV) protein, is considered to play an important role in primary influenza virus infection and postinfluenza secondary bacterial pneumonia in mice. The functional role of PB1-F2 has been reported to be a strain-specific and host-specific phenomenon. Its precise contribution to the pathogenicity and transmission of influenza virus in mammalian host, such as swine, and avian hosts, such as turkeys, remain largely unknown. In this study, we explored the role of PB1-F2 protein of triple-reassortant (TR) H3N2 swine influenza virus (SIV) in pigs and turkeys. Using the eight-plasmid reverse genetics system, we rescued wild-type SIV A/swine/Minnesota/1145/2007 (H3N2) (SIV 1145-WT), a PB1-F2 knockout mutant (SIV 1145-KO), and its N66S variant (SIV 1145-N66S). The ablation of PB1-F2 in SIV 1145 modulated early-stage apoptosis but did not affect the viral replication in swine alveolar macrophage cells. In pigs, PB1-F2 expression did not affect nasal shedding, lung viral load, immunophenotypes, and lung pathology. On the other hand, in turkeys, SIV 1145-KO infected poults, and its in-contacts developed clinical signs earlier than SIV 1145-WT groups and also displayed more extensive histopathological changes in intestine. Further, turkeys infected with SIV 1145-N66S displayed poor infectivity and transmissibility. The more extensive histopathologic changes in intestine and relative transmission advantage observed in turkeys infected with SIV 1145-KO need to be further explored. Taken together, these results emphasize the host-specific roles of PB1-F2 in the pathogenicity and transmission of IAV. Novel triple-reassortant H3N2 swine influenza virus emerged in 1998 and spread rapidly among the North American swine population. Subsequently, it showed an increased propensity to reassort, generating a range of reassortants. Unlike classical swine influenza virus, TR SIV produces a full-length PB1-F2 protein, which is considered an important

  5. PB1-F2 Protein Does Not Impact the Virulence of Triple-Reassortant H3N2 Swine Influenza Virus in Pigs but Alters Pathogenicity and Transmission in Turkeys

    PubMed Central

    Deventhiran, Jagadeeswaran; Kumar, Sandeep R. P.; Raghunath, Shobana; Elankumaran, Subbiah

    2015-01-01

    ABSTRACT PB1-F2 protein, the 11th influenza A virus (IAV) protein, is considered to play an important role in primary influenza virus infection and postinfluenza secondary bacterial pneumonia in mice. The functional role of PB1-F2 has been reported to be a strain-specific and host-specific phenomenon. Its precise contribution to the pathogenicity and transmission of influenza virus in mammalian host, such as swine, and avian hosts, such as turkeys, remain largely unknown. In this study, we explored the role of PB1-F2 protein of triple-reassortant (TR) H3N2 swine influenza virus (SIV) in pigs and turkeys. Using the eight-plasmid reverse genetics system, we rescued wild-type SIV A/swine/Minnesota/1145/2007 (H3N2) (SIV 1145-WT), a PB1-F2 knockout mutant (SIV 1145-KO), and its N66S variant (SIV 1145-N66S). The ablation of PB1-F2 in SIV 1145 modulated early-stage apoptosis but did not affect the viral replication in swine alveolar macrophage cells. In pigs, PB1-F2 expression did not affect nasal shedding, lung viral load, immunophenotypes, and lung pathology. On the other hand, in turkeys, SIV 1145-KO infected poults, and its in-contacts developed clinical signs earlier than SIV 1145-WT groups and also displayed more extensive histopathological changes in intestine. Further, turkeys infected with SIV 1145-N66S displayed poor infectivity and transmissibility. The more extensive histopathologic changes in intestine and relative transmission advantage observed in turkeys infected with SIV 1145-KO need to be further explored. Taken together, these results emphasize the host-specific roles of PB1-F2 in the pathogenicity and transmission of IAV. IMPORTANCE Novel triple-reassortant H3N2 swine influenza virus emerged in 1998 and spread rapidly among the North American swine population. Subsequently, it showed an increased propensity to reassort, generating a range of reassortants. Unlike classical swine influenza virus, TR SIV produces a full-length PB1-F2 protein, which is

  6. Seroprevalence of H1N1, H3N2 and H1N2 influenza viruses in pigs in seven European countries in 2002-2003.

    PubMed

    Van Reeth, Kristien; Brown, Ian H; Dürrwald, Ralf; Foni, Emanuela; Labarque, Geoffrey; Lenihan, Patrick; Maldonado, Jaime; Markowska-Daniel, Iwona; Pensaert, Maurice; Pospisil, Zdenek; Koch, Guus

    2008-05-01

    Avian-like H1N1 and human-like H3N2 swine influenza viruses (SIV) have been considered widespread among pigs in Western Europe since the 1980s, and a novel H1N2 reassortant with a human-like H1 emerged in the mid 1990s. This study, which was part of the EC-funded 'European Surveillance Network for Influenza in Pigs 1', aimed to determine the seroprevalence of the H1N2 virus in different European regions and to compare the relative prevalences of each SIV between regions. Laboratories from Belgium, the Czech Republic, Germany, Italy, Ireland, Poland and Spain participated in an international serosurvey. A total of 4190 sow sera from 651 farms were collected in 2002-2003 and examined in haemagglutination inhibition tests against H1N1, H3N2 and H1N2. In Belgium, Germany, Italy and Spain seroprevalence rates to each of the three SIV subtypes were high (> or =30% of the sows seropositive) to very high (> or =50%), except for a lower H1N2 seroprevalence rate in Italy (13.8%). Most sows in these countries with high pig populations had antibodies to two or three subtypes. In Ireland, the Czech Republic and Poland, where swine farming is less intensive, H1N1 was the dominant subtype (8.0-11.7% seropositives) and H1N2 and H3N2 antibodies were rare (0-4.2% seropositives). Thus, SIV of H1N1, H3N2 and H1N2 subtype are enzootic in swine producing regions of Western Europe. In Central Europe, SIV activity is low and the circulation of H3N2 and H1N2 remains to be confirmed. The evolution and epidemiology of SIV throughout Europe is being further monitored through a second 'European Surveillance Network for Influenza in Pigs'.

  7. Genetic and biological characterisation of an avian-like H1N2 swine influenza virus generated by reassortment of circulating avian-like H1N1 and H3N2 subtypes in Denmark.

    PubMed

    Trebbien, Ramona; Bragstad, Karoline; Larsen, Lars Erik; Nielsen, Jens; Bøtner, Anette; Heegaard, Peter M H; Fomsgaard, Anders; Viuff, Birgitte; Hjulsager, Charlotte Kristiane

    2013-09-18

    The influenza A virus subtypes H1N1, H1N2 and H3N2 are the most prevalent subtypes in swine. In 2003, a reassorted H1N2 swine influenza virus (SIV) subtype appeared and became prevalent in Denmark. In the present study, the reassortant H1N2 subtype was characterised genetically and the infection dynamics compared to an "avian-like" H1N1 virus by an experimental infection study. Sequence analyses were performed of the H1N2 virus. Two groups of pigs were inoculated with the reassortant H1N2 virus and an "avian-like" H1N1 virus, respectively, followed by inoculation with the opposite subtype four weeks later. Measurements of HI antibodies and acute phase proteins were performed. Nasal virus excretion and virus load in lungs were determined by real-time RT-PCR. The phylogenetic analysis revealed that the reassorted H1N2 virus contained a European "avian-like" H1-gene and a European "swine-like" N2-gene, thus being genetically distinct from most H1N2 viruses circulating in Europe, but similar to viruses reported in 2009/2010 in Sweden and Italy. Sequence analyses of the internal genes revealed that the reassortment probably arose between circulating Danish "avian-like" H1N1 and H3N2 SIVs. Infected pigs developed cross-reactive antibodies, and increased levels of acute phase proteins after inoculations. Pigs inoculated with H1N2 exhibited nasal virus excretion for seven days, peaking day 1 after inoculation two days earlier than H1N1 infected pigs and at a six times higher level. The difference, however, was not statistically significant. Pigs euthanized on day 4 after inoculation, had a high virus load in all lung lobes. After the second inoculation, the nasal virus excretion was minimal. There were no clinical sign except elevated body temperature under the experimental conditions. The "avian-like" H1N2 subtype, which has been established in the Danish pig population at least since 2003, is a reassortant between circulating swine "avian-like" H1N1 and H3N2. The Danish

  8. The origin of the PB1 segment of swine influenza A virus subtype H1N2 determines viral pathogenicity in mice.

    PubMed

    Metreveli, Giorgi; Gao, Qinshan; Mena, Ignacio; Schmolke, Mirco; Berg, Mikael; Albrecht, Randy A; García-Sastre, Adolfo

    2014-08-08

    Swine appear to be a key species in the generation of novel human influenza pandemics. Previous pandemic viruses are postulated to have evolved in swine by reassortment of avian, human, and swine influenza viruses. The human pandemic influenza viruses that emerged in 1957 and 1968 as well as swine viruses circulating since 1998 encode PB1 segments derived from avian influenza viruses. Here we investigate the possible role in viral replication and virulence of the PB1 gene segments present in two swine H1N2 influenza A viruses, A/swine/Sweden/1021/2009(H1N2) (sw 1021) and A/swine/Sweden/9706/2010(H1N2) (sw 9706), where the sw 1021 virus has shown to be more pathogenic in mice. By using reverse genetics, we swapped the PB1 genes of these two viruses. Similar to the sw 9706 virus, chimeric sw 1021 virus carrying the sw 9706 PB1 gene was not virulent in mice. In contrast, replacement of the PB1 gene of the sw 9706 virus by that from sw 1021 virus resulted in increased pathogenicity. Our study demonstrated that differences in virulence of swine influenza virus subtype H1N2 are attributed at least in part to the PB1 segment. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Antigenic Characterization of H3N2 Influenza A Viruses from Ohio Agricultural Fairs

    PubMed Central

    Feng, Zhixin; Gomez, Janet; Bowman, Andrew S.; Ye, Jianqiang; Long, Li-Ping; Nelson, Sarah W.; Yang, Jialiang; Martin, Brigitte; Jia, Kun; Nolting, Jacqueline M.; Cunningham, Fred; Cardona, Carol; Zhang, Jianqiang; Yoon, Kyoung-Jin; Slemons, Richard D.

    2013-01-01

    The demonstrated link between the emergence of H3N2 variant (H3N2v) influenza A viruses (IAVs) and swine exposure at agricultural fairs has raised concerns about the human health risk posed by IAV-infected swine. Understanding the antigenic profiles of IAVs circulating in pigs at agricultural fairs is critical to developing effective prevention and control strategies. Here, 68 H3N2 IAV isolates recovered from pigs at Ohio fairs (2009 to 2011) were antigenically characterized. These isolates were compared with other H3 IAVs recovered from commercial swine, wild birds, and canines, along with human seasonal and variant H3N2 IAVs. Antigenic cartography demonstrated that H3N2 IAV isolates from Ohio fairs could be divided into two antigenic groups: (i) the 2009 fair isolates and (ii) the 2010 and 2011 fair isolates. These same two antigenic clusters have also been observed in commercial swine populations in recent years. Human H3N2v isolates from 2010 and 2011 are antigenically clustered with swine-origin IAVs from the same time period. The isolates recovered from pigs at fairs did not cross-react with ferret antisera produced against the human seasonal H3N2 IAVs circulating during the past decade, raising the question of the degree of immunity that the human population has to swine-origin H3N2 IAVs. Our results demonstrate that H3N2 IAVs infecting pigs at fairs and H3N2v isolates were antigenically similar to the IAVs circulating in commercial swine, demonstrating that exhibition swine can function as a bridge between commercial swine and the human population. PMID:23637412

  10. Co-circulation of pandemic 2009 H1N1, classical swine H1N1 and avian-like swine H1N1 influenza viruses in pigs in China.

    PubMed

    Chen, Yan; Zhang, Jian; Qiao, Chuanling; Yang, Huanliang; Zhang, Ying; Xin, Xiaoguang; Chen, Hualan

    2013-01-01

    The pandemic A/H1N1 influenza viruses emerged in both Mexico and the United States in March 2009, and were transmitted efficiently in the human population. They were transmitted occasionally from humans to other mammals including pigs, dogs and cats. In this study, we report the isolation and genetic analysis of novel viruses in pigs in China. These viruses were related phylogenetically to the pandemic 2009 H1N1 influenza viruses isolated from humans and pigs, which indicates that the pandemic virus is currently circulating in swine populations, and this hypothesis was further supported by serological surveillance of pig sera collected within the same period. Furthermore, we isolated another two H1N1 viruses belonging to the lineages of classical swine H1N1 virus and avian-like swine H1N1 virus, respectively. Multiple genetic lineages of H1N1 viruses are co-circulating in the swine population, which highlights the importance of intensive surveillance for swine influenza in China. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. The replication of Bangladeshi H9N2 avian influenza viruses carrying genes from H7N3 in mammals

    PubMed Central

    Shanmuganatham, Karthik K; Jones, Jeremy C; Marathe, Bindumadhav M; Feeroz, Mohammed M; Jones-Engel, Lisa; Walker, David; Turner, Jasmine; Rabiul Alam, S M; Kamrul Hasan, M; Akhtar, Sharmin; Seiler, Patrick; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2016-01-01

    H9N2 avian influenza viruses are continuously monitored by the World Health Organization because they are endemic; they continually reassort with H5N1, H7N9 and H10N8 viruses; and they periodically cause human infections. We characterized H9N2 influenza viruses carrying internal genes from highly pathogenic H7N3 viruses, which were isolated from chickens or quail from live-bird markets in Bangladesh between 2010 and 2013. All of the H9N2 viruses used in this study carried mammalian host-specific mutations. We studied their replication kinetics in normal human bronchoepithelial cells and swine tracheal and lung explants, which exhibit many features of the mammalian airway epithelium and serve as a mammalian host model. All H9N2 viruses replicated to moderate-to-high titers in the normal human bronchoepithelial cells and swine lung explants, but replication was limited in the swine tracheal explants. In Balb/c mice, the H9N2 viruses were nonlethal, replicated to moderately high titers and the infection was confined to the lungs. In the ferret model of human influenza infection and transmission, H9N2 viruses possessing the Q226L substitution in hemagglutinin replicated well without clinical signs and spread via direct contact but not by aerosol. None of the H9N2 viruses tested were resistant to the neuraminidase inhibitors. Our study shows that the Bangladeshi H9N2 viruses have the potential to infect humans and highlights the importance of monitoring and characterizing this influenza subtype to better understand the potential risk these viruses pose to humans. PMID:27094903

  12. The replication of Bangladeshi H9N2 avian influenza viruses carrying genes from H7N3 in mammals.

    PubMed

    Shanmuganatham, Karthik K; Jones, Jeremy C; Marathe, Bindumadhav M; Feeroz, Mohammed M; Jones-Engel, Lisa; Walker, David; Turner, Jasmine; Rabiul Alam, S M; Kamrul Hasan, M; Akhtar, Sharmin; Seiler, Patrick; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2016-04-20

    H9N2 avian influenza viruses are continuously monitored by the World Health Organization because they are endemic; they continually reassort with H5N1, H7N9 and H10N8 viruses; and they periodically cause human infections. We characterized H9N2 influenza viruses carrying internal genes from highly pathogenic H7N3 viruses, which were isolated from chickens or quail from live-bird markets in Bangladesh between 2010 and 2013. All of the H9N2 viruses used in this study carried mammalian host-specific mutations. We studied their replication kinetics in normal human bronchoepithelial cells and swine tracheal and lung explants, which exhibit many features of the mammalian airway epithelium and serve as a mammalian host model. All H9N2 viruses replicated to moderate-to-high titers in the normal human bronchoepithelial cells and swine lung explants, but replication was limited in the swine tracheal explants. In Balb/c mice, the H9N2 viruses were nonlethal, replicated to moderately high titers and the infection was confined to the lungs. In the ferret model of human influenza infection and transmission, H9N2 viruses possessing the Q226L substitution in hemagglutinin replicated well without clinical signs and spread via direct contact but not by aerosol. None of the H9N2 viruses tested were resistant to the neuraminidase inhibitors. Our study shows that the Bangladeshi H9N2 viruses have the potential to infect humans and highlights the importance of monitoring and characterizing this influenza subtype to better understand the potential risk these viruses pose to humans.

  13. A novel monoclonal antibody effective against lethal challenge with swine-lineage and 2009 pandemic H1N1 influenza viruses in mice

    USDA-ARS?s Scientific Manuscript database

    The HA protein of the 2009 pandemic H1N1viruses (14 H1N1pdm) is antigenically closely related to the HA of classical North American swine H1N1 influenza viruses (cH1N1). Since 1998, through reassortment and incorporation of HA genes from human H3N2 and H1N1 influenza viruses, swine influenza strains...

  14. Pathogenicity and Transmissibility of Novel Reassortant H3N2 Influenza Viruses with 2009 Pandemic H1N1 Genes in Pigs

    PubMed Central

    Ma, Jingjiao; Shen, Huigang; Liu, Qinfang; Bawa, Bhupinder; Qi, Wenbao; Duff, Michael; Lang, Yuekun; Lee, Jinhwa; Yu, Hai; Bai, Jianfa; Tong, Guangzhi; Hesse, Richard A.; Richt, Jürgen A.

    2014-01-01

    ABSTRACT At least 10 different genotypes of novel reassortant H3N2 influenza viruses with 2009 pandemic H1N1 [A(H1N1)pdm09] gene(s) have been identified in U.S. pigs, including the H3N2 variant with a single A(H1N1)pdm09 M gene, which has infected more than 300 people. To date, only three genotypes of these viruses have been evaluated in animal models, and the pathogenicity and transmissibility of the other seven genotype viruses remain unknown. Here, we show that three H3N2 reassortant viruses that contain 3 (NP, M, and NS) or 5 (PA, PB2, NP, M, and NS) genes from A(H1N1)pdm09 were pathogenic in pigs, similar to the endemic H3N2 swine virus. However, the reassortant H3N2 virus with 3 A(H1N1)pdm09 genes and a recent human influenza virus N2 gene was transmitted most efficiently among pigs, whereas the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes was transmitted less efficiently than the endemic H3N2 virus. Interestingly, the polymerase complex of reassortant H3N2 virus with 5 A(H1N1)pdm09 genes showed significantly higher polymerase activity than those of endemic and reassortant H3N2 viruses with 3 A(H1N1)pdm09 genes. Further studies showed that an avian-like glycine at position 228 at the hemagglutinin (HA) receptor binding site is responsible for inefficient transmission of the reassortant H3N2 virus with 5 A(H1N1)pdm09 genes. Taken together, our results provide insights into the pathogenicity and transmissibility of novel reassortant H3N2 viruses in pigs and suggest that a mammalian-like serine at position 228 in the HA is critical for the transmissibility of these reassortant H3N2 viruses. IMPORTANCE Swine influenza is a highly contagious zoonotic disease that threatens animal and public health. Introduction of 2009 pandemic H1N1 virus [A(H1N1)pdm09] into swine herds has resulted in novel reassortant influenza viruses in swine, including H3N2 and H1N2 variants that have caused human infections in the United States. We showed that reassortant H3N2 influenza

  15. Characterization of a newly emerged genetic cluster of H1N1 and H1N2 swine influenza virus in the United States.

    PubMed

    Vincent, Amy L; Ma, Wenjun; Lager, Kelly M; Gramer, Marie R; Richt, Juergen A; Janke, Bruce H

    2009-10-01

    H1 influenza A viruses that were distinct from the classical swine H1 lineage were identified in pigs in Canada in 2003–2004; antigenic and genetic characterization identified the hemagglutinin (HA) as human H1 lineage. The viruses identified in Canadian pigs were human lineage in entirety or double (human–swine) reassortants. Here, we report the whole genome sequence analysis of four human-like H1 viruses isolated from U.S. swine in 2005 and 2007. All four isolates were characterized as triple reassortants with an internal gene constellation similar to contemporary U.S. swine influenza virus (SIV), with HA and neuraminidase (NA) most similar to human influenza virus lineages. A 2007 human-like H1N1 was evaluated in a pathogenesis and transmission model and compared to a 2004 reassortant H1N1 SIV isolate with swine lineage HA and NA. The 2007 isolate induced disease typical of influenza virus and was transmitted to contact pigs; however, the kinetics and magnitude differed from the 2004 H1N1 SIV. This study indicates that the human-like H1 SIV can efficiently replicate and transmit in the swine host and now co-circulates with contemporary SIVs as a distinct genetic cluster of H1 SIV.

  16. Antigenic Detection of Human Strain of Influenza Virus A (H3N2) in Swine Populations at Three Locations in Nigeria and Ghana during the Dry Early Months of 2014.

    PubMed

    Adeola, O A; Olugasa, B O; Emikpe, B O

    2016-03-01

    Since the first detection of human H3N2 influenza virus in Taiwanese pigs in 1970, infection of pigs with wholly human viruses has been known to occur in other parts of the world. These viruses, referred to as human-like H3N2 viruses, have been known to cause clinical and subclinical infections of swine populations. Due to the paucity and complete unavailability of information on transmission of influenza viruses from other species, especially humans, to swine in Nigeria and Ghana, respectively, this study was designed to investigate the presence and prevalence of a human strain of influenza A (H3N2) in swine populations at three locations in two cities within these two West African countries in January and February, 2014. Using stratified random technique, nasal swab specimens were collected from seventy-five (75) pigs at two locations in Ibadan, Nigeria and from fifty (50) pigs in Kumasi, Ghana. These specimens were tested directly by a sensitive Quantitative Solid Phase Antigen-detection Sandwich ELISA using anti-A/Brisbane/10/2007 haemagglutinin monoclonal antibody. Influenza virus A/Brisbane/10/2007 (H3N2) was detected among pigs at the three study locations, with an aggregate prevalence of 4.0% for the two locations in Ibadan, Nigeria and also 4.0% for Kumasi, Ghana. Transmission of influenza viruses from other species to swine portends serious sinister prospects for genetic reassortment and evolvement of novel viruses. We therefore recommend that further studies should be carried out to investigate the presence of other circulating human and avian influenza viruses in swine populations in West Africa and also determine the extent of genetic reassortment of strains circulating among these pigs. This would provide an early warning system for detection of novel influenza viruses, which could have pandemic potentials. © 2015 Blackwell Verlag GmbH.

  17. Reassortment between swine H3N2 and 2009 pandemic H1N1 in the United States resulted in influenza A viruses with diverse genetic constellations with variable virulence in pigs

    USDA-ARS?s Scientific Manuscript database

    Repeated spillovers of the H1N1 pandemic virus (H1N1pdm09) from humans to pigs resulted in substantial evolution of swine influenza viruses, contributing to the genetic and antigenic diversity of influenza A virus (IAV) currently circulating in swine. The reassortment with endemic swine viruses and ...

  18. Novel reassortant influenza A(H1N2) virus derived from A(H1N1)pdm09 virus isolated from swine, Japan, 2012.

    PubMed

    Kobayashi, Miho; Takayama, Ikuyo; Kageyama, Tsutomu; Tsukagoshi, Hiroyuki; Saitoh, Mika; Ishioka, Taisei; Yokota, Yoko; Kimura, Hirokazu; Tashiro, Masato; Kozawa, Kunihisa

    2013-12-01

    We isolated a novel influenza virus A(H1N2) strain from a pig on January 13, 2012, in Gunma Prefecture, Japan. Phylogenetic analysis showed that the strain was a novel type of double-reassortant virus derived from the swine influenza virus strains H1N1pdm09 and H1N2, which were prevalent in Gunma at that time.

  19. Genetic and biological characterisation of an avian-like H1N2 swine influenza virus generated by reassortment of circulating avian-like H1N1 and H3N2 subtypes in Denmark

    PubMed Central

    2013-01-01

    Background The influenza A virus subtypes H1N1, H1N2 and H3N2 are the most prevalent subtypes in swine. In 2003, a reassorted H1N2 swine influenza virus (SIV) subtype appeared and became prevalent in Denmark. In the present study, the reassortant H1N2 subtype was characterised genetically and the infection dynamics compared to an “avian-like” H1N1 virus by an experimental infection study. Methods Sequence analyses were performed of the H1N2 virus. Two groups of pigs were inoculated with the reassortant H1N2 virus and an “avian-like” H1N1 virus, respectively, followed by inoculation with the opposite subtype four weeks later. Measurements of HI antibodies and acute phase proteins were performed. Nasal virus excretion and virus load in lungs were determined by real-time RT-PCR. Results The phylogenetic analysis revealed that the reassorted H1N2 virus contained a European “avian-like” H1-gene and a European “swine-like” N2-gene, thus being genetically distinct from most H1N2 viruses circulating in Europe, but similar to viruses reported in 2009/2010 in Sweden and Italy. Sequence analyses of the internal genes revealed that the reassortment probably arose between circulating Danish “avian-like” H1N1 and H3N2 SIVs. Infected pigs developed cross-reactive antibodies, and increased levels of acute phase proteins after inoculations. Pigs inoculated with H1N2 exhibited nasal virus excretion for seven days, peaking day 1 after inoculation two days earlier than H1N1 infected pigs and at a six times higher level. The difference, however, was not statistically significant. Pigs euthanized on day 4 after inoculation, had a high virus load in all lung lobes. After the second inoculation, the nasal virus excretion was minimal. There were no clinical sign except elevated body temperature under the experimental conditions. Conclusions The “avian-like” H1N2 subtype, which has been established in the Danish pig population at least since 2003, is a reassortant

  20. Evolution of H3N2v viruses in North American swine and humans, 2009-2011

    USDA-ARS?s Scientific Manuscript database

    Novel H3N2 influenza viruses (H3N2v) containing seven genome segments from swine-lineage triple reassortant H3N2 viruses and a 2009 pandemic H1N1 (H1N1pdm09) matrix protein segment (pM) have been isolated from 12 humans in the United States between August – December 2011. To understand the evolution...

  1. Protective efficacy of an inactivated Eurasian avian-like H1N1 swine influenza vaccine against homologous H1N1 and heterologous H1N1 and H1N2 viruses in mice.

    PubMed

    Sui, Jinyu; Yang, Dawei; Qiao, Chuanling; Xu, Huiyang; Xu, Bangfeng; Wu, Yunpu; Yang, Huanliang; Chen, Yan; Chen, Hualan

    2016-07-19

    Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses are prevalent in pigs in Europe and Asia, but occasionally cause human infection, which raises concern about their pandemic potential. Here, we produced a whole-virus inactivated vaccine with an EA H1N1 strain (A/swine/Guangxi/18/2011, SW/GX/18/11) and evaluated its efficacy against homologous H1N1 and heterologous H1N1 and H1N2 influenza viruses in mice. A strong humoral immune response, which we measured by hemagglutination inhibition (HI) and virus neutralization (VN), was induced in the vaccine-inoculated mice upon challenge. The inactivated SW/GX/18/11 vaccine provided complete protection against challenge with homologous SW/GX/18/11 virus in mice and provided effective protection against challenge with heterologous H1N1 and H1N2 viruses with distinctive genomic combinations. Our findings suggest that this EA H1N1 vaccine can provide protection against both homologous H1N1 and heterologous H1N1 or H1N2 virus infection. As such, it is an excellent vaccine candidate to prevent H1N1 swine influenza. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Treatment and Prevention of Pandemic H1N1 Influenza.

    PubMed

    Rewar, Suresh; Mirdha, Dashrath; Rewar, Prahlad

    2015-01-01

    Swine influenza is a respiratory infection common to pigs worldwide caused by type A influenza viruses, principally subtypes H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3. Swine influenza viruses also can cause moderate to severe illness in humans and affect persons of all age groups. People in close contact with swine are at especially high risk. Until recently, epidemiological study of influenza was limited to resource-rich countries. The World Health Organization declared an H1N1 pandemic on June 11, 2009, after more than 70 countries reported 30,000 cases of H1N1 infection. In 2015, incidence of swine influenza increased substantially to reach a 5-year high. In India in 2015, 10,000 cases of swine influenza were reported with 774 deaths. The Centers for Disease Control and Prevention recommend real-time polymerase chain reaction as the method of choice for diagnosing H1N1. Antiviral drugs are the mainstay of clinical treatment of swine influenza and can make the illness milder and enable the patient to feel better faster. Antiviral drugs are most effective when they are started within the first 48 hours after the clinical signs begin, although they also may be used in severe or high-risk cases first seen after this time. The Centers for Disease Control and Prevention recommends use of oseltamivir (Tamiflu, Genentech) or zanamivir (Relenza, GlaxoSmithKline). Prevention of swine influenza has 3 components: prevention in swine, prevention of transmission to humans, and prevention of its spread among humans. Because of limited treatment options, high risk for secondary infection, and frequent need for intensive care of individuals with H1N1 pneumonia, environmental control, including vaccination of high-risk populations and public education are critical to control of swine influenza out breaks. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  3. The repeated introduction of the H3N2 virus from human to swine during 1979-1993 in China.

    PubMed

    Zhu, Wenfei; Yang, Shuai; Dong, Libo; Yang, Lei; Tang, Jing; Zou, Xiaohui; Chen, Tao; Yang, Jing; Shu, Yuelong

    2015-07-01

    Limited data are available regarding the swine influenza viruses (SIVs) that circulated in Mainland China prior to the 1990s. Eleven H3N2 virus strains were isolated from swine populations from 1979 to 1992. To determine the origin and tendency of these SIVs, the phylogenetic and antigenic properties of these viruses were analyzed based on the whole genome sequenced and the HI titrations with post-infection ferret antisera against influenza A (H3N2) virus isolates of swine and human origin. The results revealed that these 11 SIVs originated from humans and were not maintained in swine populations, indicating the interspecies transmission from humans to pigs occurred frequently and independently throughout these periods. However, human H3N2 viruses might not have the ability to circulate in pig herds. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Novel Reassortant Influenza A(H1N2) Virus Derived from A(H1N1)pdm09 Virus Isolated from Swine, Japan, 2012

    PubMed Central

    Kobayashi, Miho; Takayama, Ikuyo; Kageyama, Tsutomu; Tsukagoshi, Hiroyuki; Saitoh, Mika; Ishioka, Taisei; Yokota, Yoko; Kimura, Hirokazu; Tashiro, Masato

    2013-01-01

    We isolated a novel influenza virus A(H1N2) strain from a pig on January 13, 2012, in Gunma Prefecture, Japan. Phylogenetic analysis showed that the strain was a novel type of double-reassortant virus derived from the swine influenza virus strains H1N1pdm09 and H1N2, which were prevalent in Gunma at that time. PMID:24274745

  5. Serological Evidence of Pandemic H1N1 Influenza Virus Infections in Greek Swine.

    PubMed

    Kyriakis, C S; Papatsiros, V G; Athanasiou, L V; Valiakos, G; Brown, I H; Simon, G; Van Reeth, K; Tsiodras, S; Spyrou, V; Billinis, C

    2016-08-01

    The introduction of the 2009 pandemic H1N1 (pH1N1) influenza virus in pigs changed the epidemiology of influenza A viruses (IAVs) in swine in Europe and the rest of the world. Previously, three IAV subtypes were found in the European pig population: an avian-like H1N1 and two reassortant H1N2 and H3N2 viruses with human-origin haemagglutinin (HA) and neuraminidase proteins and internal genes of avian decent. These viruses pose antigenically distinct HAs, which allow the retrospective diagnosis of infection in serological investigations. However, cross-reactions between the HA of pH1N1 and the HAs of the other circulating H1 IAVs complicate serological diagnosis. The prevalence of IAVs in Greek swine has been poorly investigated. In this study, we examined and compared haemagglutination inhibition (HI) antibody titres against previously established IAVs and pH1N1 in 908 swine sera from 88 herds, collected before and after the 2009 pandemic. While we confirmed the historic presence of the three IAVs established in European swine, we also found that 4% of the pig sera examined after 2009 had HI antibodies only against the pH1N1 virus. Our results indicate that pH1N1 is circulating in Greek pigs and stress out the importance of a vigorous virological surveillance programme. © 2015 Blackwell Verlag GmbH.

  6. Genetic and biological characterization of two novel reassortant H5N6 swine influenza viruses in mice and chickens.

    PubMed

    Li, Xuyong; Fu, Yuguang; Yang, Jiayun; Guo, Jing; He, Jijun; Guo, Jianhong; Weng, Shaoting; Jia, Yane; Liu, Bin; Li, Xiaoyang; Zhu, Qiyun; Chen, Hualan

    2015-12-01

    Novel H5N6 influenza A viruses have infected birds and human beings and caused four human clinical cases in China since 2014. The pig, as a mixing vessel, plays an important role for influenza virus reassortment and transmission. Towards this, routine surveillance for swine influenza in Guangdong province was conducted in 2014. In this study, we reported the biological characterization of two H5N6 influenza viruses isolated from healthy pigs in Guangdong province. Genetic analysis indicates that the two viruses are reassortants of 2.3.4.4 H5N1 and H6N6 avian influenza viruses with a high similarity to duck and human H5N6 influenza viruses isolated from Guangdong province. The data from chicken and mouse experiments show that the viruses are highly pathogenic in chickens and result in a systemic infection, and replicate in the mouse lung accompanying with a clinical inflammatory pathology. The results of the study demonstrate that the two H5N6 influenza viruses isolated from swine are the avian-originated viruses and have not adapted to swine population yet. However, they might keep evolving and pose a potential risk to public health and the continued surveillance of swine influenza should be strengthened. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Outbreak of Influenza A (H3N2) Variant Virus Infection among Attendees of an Agricultural Fair, Pennsylvania, USA, 2011

    PubMed Central

    Greenbaum, Adena; Moll, Maria E.; Lando, James; Moore, Erin L.; Ganatra, Rahul; Biggerstaff, Matthew; Lam, Eugene; Smith, Erica E.; Storms, Aaron D.; Miller, Jeffrey R.; Dato, Virginia; Nalluswami, Kumar; Nambiar, Atmaram; Silvestri, Sharon A.; Lute, James R.; Ostroff, Stephen; Hancock, Kathy; Branch, Alicia; Trock, Susan C.; Klimov, Alexander; Shu, Bo; Brammer, Lynnette; Epperson, Scott; Finelli, Lyn; Jhung, Michael A.

    2012-01-01

    During August 2011, influenza A (H3N2) variant [A(H3N2)v] virus infection developed in a child who attended an agricultural fair in Pennsylvania, USA; the virus resulted from reassortment of a swine influenza virus with influenza A(H1N1)pdm09. We interviewed fair attendees and conducted a retrospective cohort study among members of an agricultural club who attended the fair. Probable and confirmed cases of A(H3N2)v virus infection were defined by serology and genomic sequencing results, respectively. We identified 82 suspected, 4 probable, and 3 confirmed case-patients who attended the fair. Among 127 cohort study members, the risk for suspected case status increased as swine exposure increased from none (4%; referent) to visiting swine exhibits (8%; relative risk 2.1; 95% CI 0.2–53.4) to touching swine (16%; relative risk 4.4; 95% CI 0.8–116.3). Fairs may be venues for zoonotic transmission of viruses with epidemic potential; thus, health officials should investigate respiratory illness outbreaks associated with agricultural events. PMID:23171635

  8. A Historical Perspective of Influenza A(H1N2) Virus

    PubMed Central

    McVernon, Jodie; Hall, Robert; Leder, Karin

    2014-01-01

    The emergence and transition to pandemic status of the influenza A(H1N1)A(H1N1)pdm09) virus in 2009 illustrated the potential for previously circulating human viruses to re-emerge in humans and cause a pandemic after decades of circulating among animals. Within a short time of the initial emergence of A(H1N1)pdm09 virus, novel reassortants were isolated from swine. In late 2011, a variant (v) H3N2 subtype was isolated from humans, and by 2012, the number of persons infected began to increase with limited person-to-person transmission. During 2012 in the United States, an A(H1N2)v virus was transmitted to humans from swine. During the same year, Australia recorded its first H1N2 subtype infection among swine. The A(H3N2)v and A(H1N2)v viruses contained the matrix protein from the A(H1N1)pdm09 virus, raising the possibility of increased transmissibility among humans and underscoring the potential for influenza pandemics of novel swine-origin viruses. We report on the differing histories of A(H1N2) viruses among humans and animals. PMID:24377419

  9. A historical perspective of influenza A(H1N2) virus.

    PubMed

    Komadina, Naomi; McVernon, Jodie; Hall, Robert; Leder, Karin

    2014-01-01

    The emergence and transition to pandemic status of the influenza A(H1N1)A(H1N1)pdm09) virus in 2009 illustrated the potential for previously circulating human viruses to re-emerge in humans and cause a pandemic after decades of circulating among animals. Within a short time of the initial emergence of A(H1N1)pdm09 virus, novel reassortants were isolated from swine. In late 2011, a variant (v) H3N2 subtype was isolated from humans, and by 2012, the number of persons infected began to increase with limited person-to-person transmission. During 2012 in the United States, an A(H1N2)v virus was transmitted to humans from swine. During the same year, Australia recorded its first H1N2 subtype infection among swine. The A(H3N2)v and A(H1N2)v viruses contained the matrix protein from the A(H1N1)pdm09 virus, raising the possibility of increased transmissibility among humans and underscoring the potential for influenza pandemics of novel swine-origin viruses. We report on the differing histories of A(H1N2) viruses among humans and animals.

  10. Virulence and transmissibility of H1N2 influenza virus in ferrets imply the continuing threat of triple-reassortant swine viruses.

    PubMed

    Pascua, Philippe Noriel Q; Song, Min-Suk; Lee, Jun Han; Baek, Yun Hee; Kwon, Hyeok-il; Park, Su-Jin; Choi, Eun Hye; Lim, Gyo-Jin; Lee, Ok-Jun; Kim, Si-Wook; Kim, Chul-Joong; Sung, Moon Hee; Kim, Myung Hee; Yoon, Sun-Woo; Govorkova, Elena A; Webby, Richard J; Webster, Robert G; Choi, Young-Ki

    2012-09-25

    Efficient worldwide swine surveillance for influenza A viruses is urgently needed; the emergence of a novel reassortant pandemic H1N1 (pH1N1) virus in 2009 demonstrated that swine can be the direct source of pandemic influenza and that the pandemic potential of viruses prevalent in swine populations must be monitored. We used the ferret model to assess the pathogenicity and transmissibility of predominant Korean triple-reassortant swine (TRSw) H1N2 and H3N2 influenza viruses genetically related to North American strains. Although most of the TRSw viruses were moderately pathogenic, one [A/Swine/Korea/1204/2009; Sw/1204 (H1N2)] was virulent in ferrets, causing death within 10 d of inoculation, and was efficiently transmitted to naive contact ferrets via respiratory droplets. Although molecular analysis did not reveal known virulence markers, the Sw/1204 virus acquired mutations in hemagglutinin (HA) (Asp-225-Gly) and neuraminidase (NA) (Ser-315-Asn) proteins during the single ferret passage. The contact-Sw/1204 virus became more virulent in mice, replicated efficiently in vitro, extensively infected human lung tissues ex vivo, and maintained its ability to replicate and transmit in swine. Reverse-genetics studies further indicated that the HA(225G) and NA(315N) substitutions contributed substantially in altering virulence and transmissibility. These findings support the continuing threat of some field TRSw viruses to human and animal health, reviving concerns on the capacity of pigs to create future pandemic viruses. Apart from warranting continued and enhanced global surveillance, this study also provides evidence on the emerging roles of HA(225G) and NA(315N) as potential virulence markers in mammals.

  11. H1N1 influenza viruses varying widely in hemagglutinin stability transmit efficiently from swine to swine and to ferrets.

    PubMed

    Russier, Marion; Yang, Guohua; Marinova-Petkova, Atanaska; Vogel, Peter; Kaplan, Bryan S; Webby, Richard J; Russell, Charles J

    2017-03-01

    A pandemic-capable influenza virus requires a hemagglutinin (HA) surface glycoprotein that is immunologically unseen by most people and is capable of supporting replication and transmission in humans. HA stabilization has been linked to 2009 pH1N1 pandemic potential in humans and H5N1 airborne transmissibility in the ferret model. Swine have served as an intermediate host for zoonotic influenza viruses, yet the evolutionary pressure exerted by this host on HA stability was unknown. For over 70 contemporary swine H1 and H3 isolates, we measured HA activation pH to range from pH 5.1 to 5.9 for H1 viruses and pH 5.3 to 5.8 for H3 viruses. Thus, contemporary swine isolates vary widely in HA stability, having values favored by both avian (pH >5.5) and human and ferret (pH ≤5.5) species. Using an early 2009 pandemic H1N1 (pH1N1) virus backbone, we generated three viruses differing by one HA residue that only altered HA stability: WT (pH 5.5), HA1-Y17H (pH 6.0), and HA2-R106K (pH 5.3). All three replicated in pigs and transmitted from pig-to-pig and pig-to-ferret. WT and R106 viruses maintained HA genotype and phenotype after transmission. Y17H (pH 6.0) acquired HA mutations that stabilized the HA protein to pH 5.8 after transmission to pigs and 5.5 after transmission to ferrets. Overall, we found swine support a broad range of HA activation pH for contact transmission and many recent swine H1N1 and H3N2 isolates have stabilized (human-like) HA proteins. This constitutes a heightened pandemic risk and underscores the importance of ongoing surveillance and control efforts for swine viruses.

  12. H1N1 influenza viruses varying widely in hemagglutinin stability transmit efficiently from swine to swine and to ferrets

    PubMed Central

    Yang, Guohua; Marinova-Petkova, Atanaska; Kaplan, Bryan S.; Webby, Richard J.

    2017-01-01

    A pandemic-capable influenza virus requires a hemagglutinin (HA) surface glycoprotein that is immunologically unseen by most people and is capable of supporting replication and transmission in humans. HA stabilization has been linked to 2009 pH1N1 pandemic potential in humans and H5N1 airborne transmissibility in the ferret model. Swine have served as an intermediate host for zoonotic influenza viruses, yet the evolutionary pressure exerted by this host on HA stability was unknown. For over 70 contemporary swine H1 and H3 isolates, we measured HA activation pH to range from pH 5.1 to 5.9 for H1 viruses and pH 5.3 to 5.8 for H3 viruses. Thus, contemporary swine isolates vary widely in HA stability, having values favored by both avian (pH >5.5) and human and ferret (pH ≤5.5) species. Using an early 2009 pandemic H1N1 (pH1N1) virus backbone, we generated three viruses differing by one HA residue that only altered HA stability: WT (pH 5.5), HA1-Y17H (pH 6.0), and HA2-R106K (pH 5.3). All three replicated in pigs and transmitted from pig-to-pig and pig-to-ferret. WT and R106 viruses maintained HA genotype and phenotype after transmission. Y17H (pH 6.0) acquired HA mutations that stabilized the HA protein to pH 5.8 after transmission to pigs and 5.5 after transmission to ferrets. Overall, we found swine support a broad range of HA activation pH for contact transmission and many recent swine H1N1 and H3N2 isolates have stabilized (human-like) HA proteins. This constitutes a heightened pandemic risk and underscores the importance of ongoing surveillance and control efforts for swine viruses. PMID:28282440

  13. Comparison of 2010-2011 H3N2 influenza A viruses isolated from swine and the A(H3N2)v isolated from humans in 2011

    USDA-ARS?s Scientific Manuscript database

    In the end of 2011, 12 U.S. cases of humans infected with swine H3N2 virus containing the matrix gene from pandemic H1N1 2009 virus (H1N1pdm09) were detected and named A(H3N2)v. This study used a swine model to compare the pathogenic, transmission, genetic, and antigenic properties of a human A(H3N2...

  14. Evaluation of the zoonotic potential of a novel reassortant H1N2 swine influenza virus with gene constellation derived from multiple viral sources.

    PubMed

    Lee, Jee Hoon; Pascua, Philippe Noriel Q; Decano, Arun G; Kim, Se Mi; Park, Su-Jin; Kwon, Hyeok-Il; Kim, Eun-Ha; Kim, Young-Il; Kim, HyongKyu; Kim, Seok-Yong; Song, Min-Suk; Jang, Hyung-Kwan; Park, Bong Kyun; Choi, Young Ki

    2015-08-01

    In 2011-2012, contemporary North American-like H3N2 swine influenza viruses (SIVs) possessing the 2009 pandemic H1N1 matrix gene (H3N2pM-like virus) were detected in domestic pigs of South Korea where H1N2 SIV strains are endemic. More recently, we isolated novel reassortant H1N2 SIVs bearing the Eurasian avian-like swine H1-like hemagglutinin and Korean swine H1N2-like neuraminidase in the internal gene backbone of the H3N2pM-like virus. In the present study, we clearly provide evidence on the genetic origins of the novel H1N2 SIVs virus through genetic and phylogenetic analyses. In vitro studies demonstrated that, in comparison with a pre-existing 2012 Korean H1N2 SIV [A/swine/Korea/CY03-11/2012 (CY03-11/2012)], the 2013 novel reassortant H1N2 isolate [A/swine/Korea/CY0423/2013 (CY0423-12/2013)] replicated more efficiently in differentiated primary human bronchial epithelial cells. The CY0423-12/2013 virus induced higher viral titers than the CY03-11/2012 virus in the lungs and nasal turbinates of infected mice and nasal wash samples of ferrets. Moreover, the 2013 H1N2 reassortant, but not the intact 2012 H1N2 virus, was transmissible to naïve contact ferrets via respiratory-droplets. Noting that the viral precursors have the ability to infect humans, our findings highlight the potential threat of a novel reassortant H1N2 SIV to public health and underscore the need to further strengthen influenza surveillance strategies worldwide, including swine populations. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Influenza A Viruses of Human Origin in Swine, Brazil.

    PubMed

    Nelson, Martha I; Schaefer, Rejane; Gava, Danielle; Cantão, Maurício Egídio; Ciacci-Zanella, Janice Reis

    2015-08-01

    The evolutionary origins of the influenza A(H1N1)pdm09 virus that caused the first outbreak of the 2009 pandemic in Mexico remain unclear, highlighting the lack of swine surveillance in Latin American countries. Although Brazil has one of the largest swine populations in the world, influenza was not thought to be endemic in Brazil's swine until the major outbreaks of influenza A(H1N1)pdm09 in 2009. Through phylogenetic analysis of whole-genome sequences of influenza viruses of the H1N1, H1N2, and H3N2 subtypes collected in swine in Brazil during 2009-2012, we identified multiple previously uncharacterized influenza viruses of human seasonal H1N2 and H3N2 virus origin that have circulated undetected in swine for more than a decade. Viral diversity has further increased in Brazil through reassortment between co-circulating viruses, including A(H1N1)pdm09. The circulation of multiple divergent hemagglutinin lineages challenges the design of effective cross-protective vaccines and highlights the need for additional surveillance.

  16. Reassortment between swine H3N2 and 2009 pandemic H1N1 generated diverse genetic constellations in influenza A viruses currently circulating in pigs in the United States

    USDA-ARS?s Scientific Manuscript database

    Introduction Influenza A virus (IAV) is a significant pathogen to the swine industry. Since its introduction in 2009, the H1N1 pandemic virus (H1N1pdm09) has been repeatedly transmitted from humans to swine, but onward transmission in U.S. swine was mostly restricted to its internal genes. Reassortm...

  17. Novel triple reassortant H1N2 influenza viruses bearing six internal genes of the pandemic 2009/H1N1 influenza virus were detected in pigs in China.

    PubMed

    Qiao, Chuanling; Liu, Liping; Yang, Huanliang; Chen, Yan; Xu, Huiyang; Chen, Hualan

    2014-12-01

    The pandemic A/H1N1 influenza viruses emerged in both Mexico and the United States in March 2009, and were transmitted efficiently in the human population. Transmissions of the pandemic 2009/H1N1 virus from humans to poultry and other species of mammals were reported from several continents during the course of the 2009 H1N1 pandemic. Reassortant H1N1, H1N2, and H3N2 viruses containing genes of the pandemic 2009/H1N1 viruses appeared in pigs in some countries. In winter of 2012, a total of 2600 nasal swabs were collected from healthy pigs in slaughterhouses located throughout 10 provinces in China. The isolated viruses were subjected to genetic and antigenic analysis. Two novel triple-reassortant H1N2 influenza viruses were isolated from swine in China in 2012, with the HA gene derived from Eurasian avian-like swine H1N1, the NA gene from North American swine H1N2, and the six internal genes from the pandemic 2009/H1N1 viruses. The two viruses had similar antigenic features and some significant changes in antigenic characteristics emerged when compared to the previously identified isolates. We inferred that the novel reassortant viruses in China may have arisen from the accumulation of the three types of influenza viruses, which further indicates that swine herds serve as "mixing vessels" for influenza viruses. Influenza virus reassortment is an ongoing process, and our findings highlight the urgent need for continued influenza surveillance among swine herds. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Isolation and genetic characterization of avian-like H1N1 and novel ressortant H1N2 influenza viruses from pigs in China.

    PubMed

    Yu, Hai; Zhang, Peng-Chao; Zhou, Yan-Jun; Li, Guo-Xin; Pan, Jie; Yan, Li-Ping; Shi, Xiao-Xiao; Liu, Hui-Li; Tong, Guang-Zhi

    2009-08-21

    As pigs are susceptible to both human and avian influenza viruses, they have been proposed to be intermediate hosts or mixing vessels for the generation of pandemic influenza viruses through reassortment or adaptation to the mammalian host. In this study, we reported avian-like H1N1 and novel ressortant H1N2 influenza viruses from pigs in China. Homology and phylogenetic analyses showed that the H1N1 virus (A/swine/Zhejiang/1/07) was closely to avian-like H1N1 viruses and seemed to be derived from the European swine H1N1 viruses, which was for the first time reported in China; and the two H1N2 viruses (A/swine/Shanghai/1/07 and A/swine/Guangxi/13/06) were novel ressortant H1N2 influenza viruses containing genes from the classical swine (HA, NP, M and NS), human (NA and PB1) and avian (PB2 and PA) lineages, which indicted that the reassortment among human, avian, and swine influenza viruses had taken place in pigs in China and resulted in the generation of new viruses. The isolation of avian-like H1N1 influenza virus originated from the European swine H1N1 viruses, especially the emergence of two novel ressortant H1N2 influenza viruses provides further evidence that pigs serve as intermediate hosts or "mixing vessels", and swine influenza virus surveillance in China should be given a high priority.

  19. Effects of Isatis root polysaccharide in mice infected with H3N2 swine influenza virus.

    PubMed

    Wang, Xuebing; Xue, Yang; Li, Yongliang; Liu, Fang; Yan, Yanhua; Zhang, Hongying; Jin, Qianyue

    2018-05-01

    Isatis root polysaccharide (IRPS) has gained attention in the field of virology. However, very few studies have evaluated the effects of IRPS on H3N2 swine influenza virus (SIV). The antiviral activities of IRPS against SIV were investigated in vitro through three different modes and in vivo in an experimental mouse model of SIV infection. Mice were treated by oral gavage with various doses of IRPS before being experimentally infected with SIV A/swine/Henan/2010(H3N2). The antiviral effects of IRPS were evaluated by clinical signs, weight, histopathology, cytokine levels in lung homogenates and serum nitric oxide (NO) and IgG levels at 2, 5 and 9 d post-infection. IRPS demonstrated an inhibitory effect on SIV in Madin-Darby canine kidney cells. Additionally, IRPS significantly improved symptoms, reduced pathological changes and enhanced serum levels of NO and IgG in SIV-infected mice. Furthermore, detection of cytokines in lung homogenates showed IRPS could alter cytokine production to improve immune responses and systemic ability to repair inflammation. Moreover, IRPS extenuated the pulmonary inflammatory response. The results show that various concentrations of IRPS exert antiviral effects in vitro and in vivo. In an experimental mouse model of SIV infection, IRPS at a dose of 75 mg/kg was effective. Copyright © 2018. Published by Elsevier Ltd.

  20. Reassortant swine influenza viruses isolated in Japan contain genes from pandemic A(H1N1) 2009.

    PubMed

    Kanehira, Katsushi; Takemae, Nobuhiro; Uchida, Yuko; Hikono, Hirokazu; Saito, Takehiko

    2014-06-01

    In 2013, three reassortant swine influenza viruses (SIVs)-two H1N2 and one H3N2-were isolated from symptomatic pigs in Japan; each contained genes from the pandemic A(H1N1) 2009 virus and endemic SIVs. Phylogenetic analysis revealed that the two H1N2 viruses, A/swine/Gunma/1/2013 and A/swine/Ibaraki/1/2013, were reassortants that contain genes from the following three distinct lineages: (i) H1 and nucleoprotein (NP) genes derived from a classical swine H1 HA lineage uniquely circulating among Japanese SIVs; (ii) neuraminidase (NA) genes from human-like H1N2 swine viruses; and (iii) other genes from pandemic A(H1N1) 2009 viruses. The H3N2 virus, A/swine/Miyazaki/2/2013, comprised genes from two sources: (i) hemagglutinin (HA) and NA genes derived from human and human-like H3N2 swine viruses and (ii) other genes from pandemic A(H1N1) 2009 viruses. Phylogenetic analysis also indicated that each of the reassortants may have arisen independently in Japanese pigs. A/swine/Miyazaki/2/2013 were found to have strong antigenic reactivities with antisera generated for some seasonal human-lineage viruses isolated during or before 2003, whereas A/swine/Miyazaki/2/2013 reactivities with antisera against viruses isolated after 2004 were clearly weaker. In addition, antisera against some strains of seasonal human-lineage H1 viruses did not react with either A/swine/Gunma/1/2013 or A/swine/Ibaraki/1/2013. These findings indicate that emergence and spread of these reassortant SIVs is a potential public health risk. © 2014 The Societies and Wiley Publishing Asia Pty Ltd.

  1. Serological Evidence and Risk Factors for Swine Influenza Infections among Chinese Swine Workers in Guangdong Province

    PubMed Central

    Ma, Mengmeng; Anderson, Benjamin D.; Wang, Tao; Chen, Yingan; Zhang, Dingmei; Gray, Gregory C.; Lu, Jiahai

    2015-01-01

    During July to September 2014, we performed a controlled, cross-sectional, seroepidemiologic study among 203 swine workers and 115 control subjects in Guangdong Province. Sera were tested using a hemagglutination inhibition assay against locally-isolated swine H3N2 and H1N1 viruses and commercially-obtained human influenza viral antigens. We found swine workers had a greater prevalence and odds of seropositivity against the swine H3N2 virus (17.3% vs. 7.0%; adjusted OR, 3.4; 95% CI, 1.1 -10.7). Younger age, self-report of a respiratory illness during the last 12 months, and seropositivity against seasonal H3N2 virus were identified as significant risk factors for seropositivity against swine H3N2 virus. As swine workers in China may be exposed to novel influenza viruses, it seems prudent for China to conduct special surveillance for such viruses among them. It also seems wise to offer such workers seasonal influenza vaccines with a goal to reduce cross-species influenza virus transmission. PMID:26016740

  2. Influenza A Viruses of Human Origin in Swine, Brazil

    PubMed Central

    Schaefer, Rejane; Gava, Danielle; Cantão, Maurício Egídio; Ciacci-Zanella, Janice Reis

    2015-01-01

    The evolutionary origins of the influenza A(H1N1)pdm09 virus that caused the first outbreak of the 2009 pandemic in Mexico remain unclear, highlighting the lack of swine surveillance in Latin American countries. Although Brazil has one of the largest swine populations in the world, influenza was not thought to be endemic in Brazil’s swine until the major outbreaks of influenza A(H1N1)pdm09 in 2009. Through phylogenetic analysis of whole-genome sequences of influenza viruses of the H1N1, H1N2, and H3N2 subtypes collected in swine in Brazil during 2009–2012, we identified multiple previously uncharacterized influenza viruses of human seasonal H1N2 and H3N2 virus origin that have circulated undetected in swine for more than a decade. Viral diversity has further increased in Brazil through reassortment between co-circulating viruses, including A(H1N1)pdm09. The circulation of multiple divergent hemagglutinin lineages challenges the design of effective cross-protective vaccines and highlights the need for additional surveillance. PMID:26196759

  3. Influenza A Subtype H3 Viruses in Feral Swine, United States, 2011–2012

    PubMed Central

    Feng, Zhixin; Baroch, John A.; Long, Li-Ping; Xu, Yifei; Cunningham, Frederick L.; Pedersen, Kerri; Lutman, Mark W.; Schmit, Brandon S.; Bowman, Andrew S.; DeLiberto, Thomas J.

    2014-01-01

    To determine whether, and to what extent, influenza A subtype H3 viruses were present in feral swine in the United States, we conducted serologic and virologic surveillance during October 2011–September 2012. These animals were periodically exposed to and infected with A(H3N2) viruses, suggesting they may threaten human and animal health. PMID:24751326

  4. Origins of the 2009 H1N1 influenza pandemic in swine in Mexico

    PubMed Central

    Mena, Ignacio; Nelson, Martha I; Quezada-Monroy, Francisco; Dutta, Jayeeta; Cortes-Fernández, Refugio; Lara-Puente, J Horacio; Castro-Peralta, Felipa; Cunha, Luis F; Trovão, Nídia S; Lozano-Dubernard, Bernardo; Rambaut, Andrew; van Bakel, Harm; García-Sastre, Adolfo

    2016-01-01

    Asia is considered an important source of influenza A virus (IAV) pandemics, owing to large, diverse viral reservoirs in poultry and swine. However, the zoonotic origins of the 2009 A/H1N1 influenza pandemic virus (pdmH1N1) remain unclear, due to conflicting evidence from swine and humans. There is strong evidence that the first human outbreak of pdmH1N1 occurred in Mexico in early 2009. However, no related swine viruses have been detected in Mexico or any part of the Americas, and to date the most closely related ancestor viruses were identified in Asian swine. Here, we use 58 new whole-genome sequences from IAVs collected in Mexican swine to establish that the swine virus responsible for the 2009 pandemic evolved in central Mexico. This finding highlights how the 2009 pandemic arose from a region not considered a pandemic risk, owing to an expansion of IAV diversity in swine resulting from long-distance live swine trade. DOI: http://dx.doi.org/10.7554/eLife.16777.001 PMID:27350259

  5. Simultaneous infection of pigs and people with triple-reassortant swine influenza virus H1N1 at a U.S. county fair.

    PubMed

    Killian, M L; Swenson, S L; Vincent, A L; Landgraf, J G; Shu, B; Lindstrom, S; Xu, X; Klimov, A; Zhang, Y; Bowman, A S

    2013-05-01

    Influenza-like illness was noted in people and pigs in attendance at an Ohio county fair in August 2007. The morbidity rate in swine approached 100% within 1-2 days of initial clinical signs being recognized, and approximately two dozen people developed influenza-like illness. Triple-reassortant swine H1N1 influenza viruses were identified in both pigs and people at the fair. The identified viruses (A/Sw/OH/511445/2007, A/Ohio/01/2007, and A/Ohio/02/2007) were similar to H1N1 swine influenza viruses currently found in the U.S. swine population. This case illustrates the possibility of transmission of swine influenza in settings where there is close human/swine interaction. © 2012 Blackwell Verlag GmbH.

  6. Swine Workers and Swine Influenza Virus Infections

    PubMed Central

    McCarthy, Troy; Capuano, Ana W.; Setterquist, Sharon F.; Olsen, Christopher W.; Alavanja, Michael C.; Lynch, Charles F.

    2007-01-01

    In 2004, 803 rural Iowans from the Agricultural Health Study were enrolled in a 2-year prospective study of zoonotic influenza transmission. Demographic and occupational exposure data from enrollment, 12-month, and 24-month follow-up encounters were examined for association with evidence of previous and incident influenza virus infections. When proportional odds modeling with multivariable adjustment was used, upon enrollment, swine-exposed participants (odds ratio [OR] 54.9, 95% confidence interval [CI] 13.0–232.6) and their nonswine-exposed spouses (OR 28.2, 95% CI 6.1–130.1) were found to have an increased odds of elevated antibody level to swine influenza (H1N1) virus compared with 79 nonexposed University of Iowa personnel. Further evidence of occupational swine influenza virus infections was observed through self-reported influenza-like illness data, comparisons of enrollment and follow-up serum samples, and the isolation of a reassortant swine influenza (H1N1) virus from an ill swine farmer. Study data suggest that swine workers and their nonswine-exposed spouses are at increased risk of zoonotic influenza virus infections. PMID:18258038

  7. Vaccine efficacy of live-attenuated virus, whole inactivated virus and alphavirus vectored subunit vaccines against antigenically distinct H3N2 swine influenza A viruses

    USDA-ARS?s Scientific Manuscript database

    Introduction Influenza A virus (IAV) is an important pathogen in swine, and the main intervention strategy is vaccination to induce neutralizing antibodies against the hemagglutinin (HA). Three major antigenic clusters, cyan, red, and green, were identified among H3N2 viruses circulating in pigs in ...

  8. Temperature sensitivity on growth and/or replication of H1N1, H1N2 and H3N2 influenza A viruses isolated from pigs and birds in mammalian cells.

    PubMed

    Massin, Pascale; Kuntz-Simon, Gaëlle; Barbezange, Cyril; Deblanc, Céline; Oger, Aurélie; Marquet-Blouin, Estelle; Bougeard, Stéphanie; van der Werf, Sylvie; Jestin, Véronique

    2010-05-19

    Influenza A viruses have been isolated from a wide range of animal species, aquatic birds being the reservoir for their genetic diversity. Avian influenza viruses can be transmitted to humans, directly or indirectly through an intermediate host like pig. This study aimed to define in vitro conditions that could prove useful to evaluate the potential of influenza viruses to adapt to a different host. Growth of H1N1, H1N2 and H3N2 influenza viruses belonging to different lineages isolated from birds or pigs prior to 2005 was tested on MDCK or NPTr cell lines in the presence or absence of exogenous trypsin. Virus multiplication was compared at 33, 37 and 40 degrees C, the infection site temperatures in human, swine and avian hosts, respectively. Temperature sensitivity of PB2-, NP- and M-RNA replication was also tested by quantitative real-time PCR. Multiplication of avian viruses was cold-sensitive, whatever cell type. By contrast, temperature sensitivity of swine viruses was found to depend on the virus and the host cell: for an H1N1 swine isolate from 1982, multiplication was cold-sensitive on NPTr cells and undetectable at 40 degrees C. From genetic analyses, it appears that temperature sensitivity could involve other residues than PB2 residue 627 and could affect other steps of the replication cycle than replication. Copyright 2009 Elsevier B.V. All rights reserved.

  9. [Swine influenza virus: evolution mechanism and epidemic characterization--a review].

    PubMed

    Qi, Xian; Lu, Chengping

    2009-09-01

    Pigs may play an important role in the evolution and ecology of influenza A virus. The tracheal epithelium of pigs contain both SA alpha 2,6 Gal and SA alpha 2,3 Gal receptors and can be infected with swine, human and avian viruses, therefore, pigs have been considered as an intermediate host for the adaptation of avian influenza viruses to humans or as mixing vessels for the generation of genetically reassortant viruses. Evolution patterns among swine influenza viruses including evolution of host adaptation, antigenic drift and genetic reassortment, and the latter is the main one. Unlike human influenza viruses, swine viruses have different epizootiological patterns in different areas of world, which is enzootic and geographic dependence. Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2, and these include classical swine H1N1, avian-like H1N1, human-like H3N2, reassortant H3N2 and various genotype H1N2 viruses. In Europe, North America and China, influenza A viruses circulating in pigs are distinct in the genetic characteristics and genetic sources. Since 1979, three subtypes, avian-like H1N1, reassortant H1N2 and H3N2 viruses, have been co-circulating in European swine. Before 1998, classical H1N1 viruses were the exclusive cause of swine influenza in North America. However, after that, three triple-reassortant H1N2, H3N2 and H1N1 viruses with genes of human, swine and avian virus began to emerge in pigs. Genetically, the pandemic viruses emerging in human, so called influenza A (H1N1) viruses, contain genes from both Europe and North American SIV lineages. SIV is not the same as Europe and the United States in the prevalence and genetic background in China, mainly classical swine H1N1 and human-like H3N2 type virus. However, in recent years, SIV from Europe and North America have been introduced into Chinese pig herds, so more attention should be given on the evolutionary of SIV in China

  10. Systemic lupus erythematosus (SLE) pneumonitis mimicking swine influenza pneumonia during the swine influenza (H1N1) pandemic.

    PubMed

    Cunha, Burke A; Syed, Uzma; Mickail, Nardeen

    2011-01-01

    We present a young woman with a negative medical history who presented with acute systemic lupus erythematosus (SLE) pneumonitis mimicking swine influenza (H1N1) pneumonia. Because this case occurred during the H1N1 pandemic, the initial diagnostic impression was of H1N1 pneumonia. Although her clinical and laboratory findings were consistent with the diagnosis of H1N1 pneumonia, e.g., fever, sore throat, dry cough, arthralgias, myalgias, thrombocytopenia, relative lymphopenia, and elevated serum transaminases, some findings suggested an alternate diagnosis, e.g., leukopenia, a highly elevated erythrocyte sedimentation rate, highly elevated serum ferritin levels, elevated antinuclear antibody (ANA) levels, and double-stranded (DS) DNA titers. Her chest x-ray showed an accentuation of basilar lung markings, with a small pleural effusion similar to the chest x-ray findings of early H1N1 pneumonia. Initially, her headaches were thought to be related to central nervous system manifestations of H1N1. After laboratory test results demonstrated elevated ANA and anti-DS DNA titers, she was diagnosed with acute SLE pneumonitis. The take-home lesson for clinicians is that other infectious diseases, e.g., human parainfluenza virus or Legionnaires' disease, can mimic H1N1 pneumonia during an influenza pandemic. Excluding asthma, congestive heart failure, exacerbations of acute bronchitis, chronic obstructive pulmonary disorder, and pulmonary interstitial disease, noninfectious mimics of H1N1 are extremely rare. To the best of our knowledge, this is the first reported case of de novo SLE pneumonitis mimicking H1N1 pneumonia during the swine influenza pandemic. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Virological and serological study of human infection with swine influenza A H1N1 virus in China.

    PubMed

    Zu, Rongqiang; Dong, Libo; Qi, Xian; Wang, Dayan; Zou, Shumei; Bai, Tian; Li, Ming; Li, Xiaodan; Zhao, Xiang; Xu, Cuiling; Huo, Xiang; Xiang, Nijuan; Yang, Shuai; Li, Zi; Xu, Zhen; Wang, Hua; Shu, Yuelong

    2013-11-01

    Pigs are considered to be "mixing vessels" for the emergence of influenza viruses with pandemic potential. 2009 Pandemic Influenza H1N1 further proved this hypothesis, and raised the needs for risk assessment of human cases caused by swine influenza virus. A field investigation was conducted after a case identified with infection of European avian-like swine influenza H1N1 virus. The diagnosis was confirmed by real-time PCR, virus isolation, whole genome sequencing and serological assays. Samples from local pigs and close contacts were tested to identify the source of infection and route of transmission. The virus from the index case was similar to viruses circulating in the local pigs. The case's grandfather was asymptomatic with sero-conversion. A total of 42.8% of swine sera were positive for European avian-like swine H1N1. This study highlighted the importance of performing surveillance on swine influenza to monitor new virus emergence in humans. © 2013 Elsevier Inc. All rights reserved.

  12. Different evolutionary trends of swine H1N2 influenza viruses in Italy compared to European viruses

    PubMed Central

    2013-01-01

    European H1N2 swine influenza viruses (EU H1N2SIVs) arose from multiple reassortment events among human H1N1, human H3N2, and avian influenza viruses. We investigated the evolutionary dynamics of 53 Italian H1N2 strains by comparing them with EU H1N2 SIVs. Hemagglutinin (HA) phylogeny revealed Italian strains fell into four groups: Group A and B (41 strains) had a human H1 similar to EU H1N2SIVs, which probably originated in 1986. However Group B (38 strains) formed a subgroup that had a two-amino acid deletion at positions 146/147 in HA. Group C (11 strains) contained an avian H1 that probably originated in 1996, and Group D (1 strain) had an H1 characteristic of the 2009 pandemic strain. Neuraminidase (NA) phylogeny suggested a series of genomic reassortments had occurred. Group A had an N2 that originated from human H3N2 in the late 1970s. Group B had different human N2 that most likely arose from a reassortment with the more recent human H3N2 virus, which probably occurred in 2000. Group C had an avian-like H1 combined with an N2 gene from one of EU H1N2SIVs, EU H3N2SIVs or Human H3N2. Group D was part of the EU H3N2SIVs clade. Although selection pressure for HA and NA was low, several positively selected sites were identified in both proteins, some of which were antigenic, suggesting selection influenced the evolution of SIV. The data highlight different evolutionary trends between European viruses and currently circulating Italian B strains and show the establishment of reassortant strains involving human viruses in Italian pigs. PMID:24289094

  13. Different evolutionary trends of swine H1N2 influenza viruses in Italy compared to European viruses.

    PubMed

    Moreno, Ana; Gabanelli, Elena; Sozzi, Enrica; Lelli, Davide; Chiapponi, Chiara; Ciccozzi, Massimo; Zehender, Gianguglielmo; Cordioli, Paolo

    2013-12-01

    European H1N2 swine influenza viruses (EU H1N2SIVs) arose from multiple reassortment events among human H1N1, human H3N2, and avian influenza viruses. We investigated the evolutionary dynamics of 53 Italian H1N2 strains by comparing them with EU H1N2 SIVs. Hemagglutinin (HA) phylogeny revealed Italian strains fell into four groups: Group A and B (41 strains) had a human H1 similar to EU H1N2SIVs, which probably originated in 1986. However Group B (38 strains) formed a subgroup that had a two-amino acid deletion at positions 146/147 in HA. Group C (11 strains) contained an avian H1 that probably originated in 1996, and Group D (1 strain) had an H1 characteristic of the 2009 pandemic strain. Neuraminidase (NA) phylogeny suggested a series of genomic reassortments had occurred. Group A had an N2 that originated from human H3N2 in the late 1970s. Group B had different human N2 that most likely arose from a reassortment with the more recent human H3N2 virus, which probably occurred in 2000. Group C had an avian-like H1 combined with an N2 gene from one of EU H1N2SIVs, EU H3N2SIVs or Human H3N2. Group D was part of the EU H3N2SIVs clade. Although selection pressure for HA and NA was low, several positively selected sites were identified in both proteins, some of which were antigenic, suggesting selection influenced the evolution of SIV. The data highlight different evolutionary trends between European viruses and currently circulating Italian B strains and show the establishment of reassortant strains involving human viruses in Italian pigs.

  14. Cross-Species Infectivity of H3N8 Influenza Virus in an Experimental Infection in Swine

    PubMed Central

    Solórzano, Alicia; Foni, Emanuela; Córdoba, Lorena; Baratelli, Massimiliano; Razzuoli, Elisabetta; Bilato, Dania; Martín del Burgo, María Ángeles; Perlin, David S.; Martínez, Jorge; Martínez-Orellana, Pamela; Fraile, Lorenzo; Chiapponi, Chiara; Amadori, Massimo; del Real, Gustavo

    2015-01-01

    ABSTRACT Avian influenza A viruses have gained increasing attention due to their ability to cross the species barrier and cause severe disease in humans and other mammal species as pigs. H3 and particularly H3N8 viruses, are highly adaptive since they are found in multiple avian and mammal hosts. H3N8 viruses have not been isolated yet from humans; however, a recent report showed that equine influenza A viruses (IAVs) can be isolated from pigs, although an established infection has not been observed thus far in this host. To gain insight into the possibility of H3N8 avian IAVs to cross the species barrier into pigs, in vitro experiments and an experimental infection in pigs with four H3N8 viruses from different origins (equine, canine, avian, and seal) were performed. As a positive control, an H3N2 swine influenza virus A was used. Although equine and canine viruses hardly replicated in the respiratory systems of pigs, avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation. Interestingly, antibodies against hemagglutinin could not be detected after infection by hemagglutination inhibition (HAI) test with avian and seal viruses. This phenomenon was observed not only in pigs but also in mice immunized with the same virus strains. Our data indicated that H3N8 IAVs from wild aquatic birds have the potential to cross the species barrier and establish successful infections in pigs that might spread unnoticed using the HAI test as diagnostic tool. IMPORTANCE Although natural infection of humans with an avian H3N8 influenza A virus has not yet been reported, this influenza A virus subtype has already crossed the species barrier. Therefore, we have examined the potential of H3N8 from canine, equine, avian, and seal origin to productively infect pigs. Our results demonstrated that avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation

  15. Cross-Species Infectivity of H3N8 Influenza Virus in an Experimental Infection in Swine.

    PubMed

    Solórzano, Alicia; Foni, Emanuela; Córdoba, Lorena; Baratelli, Massimiliano; Razzuoli, Elisabetta; Bilato, Dania; Martín del Burgo, María Ángeles; Perlin, David S; Martínez, Jorge; Martínez-Orellana, Pamela; Fraile, Lorenzo; Chiapponi, Chiara; Amadori, Massimo; del Real, Gustavo; Montoya, María

    2015-11-01

    Avian influenza A viruses have gained increasing attention due to their ability to cross the species barrier and cause severe disease in humans and other mammal species as pigs. H3 and particularly H3N8 viruses, are highly adaptive since they are found in multiple avian and mammal hosts. H3N8 viruses have not been isolated yet from humans; however, a recent report showed that equine influenza A viruses (IAVs) can be isolated from pigs, although an established infection has not been observed thus far in this host. To gain insight into the possibility of H3N8 avian IAVs to cross the species barrier into pigs, in vitro experiments and an experimental infection in pigs with four H3N8 viruses from different origins (equine, canine, avian, and seal) were performed. As a positive control, an H3N2 swine influenza virus A was used. Although equine and canine viruses hardly replicated in the respiratory systems of pigs, avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation. Interestingly, antibodies against hemagglutinin could not be detected after infection by hemagglutination inhibition (HAI) test with avian and seal viruses. This phenomenon was observed not only in pigs but also in mice immunized with the same virus strains. Our data indicated that H3N8 IAVs from wild aquatic birds have the potential to cross the species barrier and establish successful infections in pigs that might spread unnoticed using the HAI test as diagnostic tool. Although natural infection of humans with an avian H3N8 influenza A virus has not yet been reported, this influenza A virus subtype has already crossed the species barrier. Therefore, we have examined the potential of H3N8 from canine, equine, avian, and seal origin to productively infect pigs. Our results demonstrated that avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation. Surprisingly, we

  16. Comparison of two H1N2 swine influenza A viruses from disease outbreaks in pigs in Sweden during 2009 and 2010.

    PubMed

    Metreveli, Giorgi; Emmoth, Eva; Zohari, Siamak; Bálint, Adám; Widén, Frederik; Muradrasoli, Shaman; Wallgren, Per; Belák, Sándor; Leblanc, Neil; Berg, Mikael; Kiss, István

    2011-04-01

    The influenza A virus subtypes H1N1, H1N2 and H3N2 are prevalent in pig populations worldwide. In the present study, two relatively uncommon swine influenza virus (SIV) H1N2 subtypes, isolated in Sweden in 2009 and 2010, were compared regarding their molecular composition and biological characteristics. The differences regarding markers purportedly related to pathogenicity, host adaptation or replication efficiency. They included a truncated PB1-F2 protein in the earlier isolate but a full length version in the more recent one; differences in the number of haemagglutinin glycosylation sites, including a characteristic human one; and a nuclear export protein with altered export signal. Of particular interest, the NS1 amino acid sequence of swine H1N2-2009 and 2010 has a 'unique or very unusual' PDZ binding domain (RPKV) at the C-terminal of the protein, a motif that has been implicated as a virulence marker. Concerning biological properties, these viruses reached lower titre and showed reduced cytopathogenicity in MDCK cells compared with an avian-like H1N1 isolate A/swine/Lidkoping/1193/2002 belonging to the same lineage as the 2009 and 2010 isolates. The findings should contribute to better understanding of factors related to the survival/extinction of this uncommon reassortant variant.

  17. Winthrop-University Hospital Infectious Disease Division's swine influenza (H1N1) pneumonia diagnostic weighted point score system for hospitalized adults with influenza-like illnesses (ILIs) and negative rapid influenza diagnostic tests (RIDTs).

    PubMed

    Cunha, Burke A; Syed, Uzma; Stroll, Stephanie; Mickail, Nardeen; Laguerre, Marianne

    2009-01-01

    In spring 2009, a novel strain of influenza A originating in Veracruz, Mexico, quickly spread to the United States and throughout the world. This influenza A virus was the product of gene reassortment of 4 different genetic elements: human influenza, swine influenza, avian influenza, and Eurasian swine influenza. In the United States, New York was the epicenter of the swine influenza (H1N1) pandemic. Hospital emergency departments (EDs) were inundated with patients with influenza-like illnesses (ILIs) requesting screening for H1N1. Our ED screening, as well as many others, used a rapid screening test for influenza A (QuickVue A/B) because H1N1 was a variant of influenza A. The definitive laboratory test i.e., RT-PCR for H1N1 was developed by the Centers for Disease Control (Atlanta, GA) and subsequently distributed to health departments. Because of the extraordinary volume of test requests, health authorities restricted reverse transcription polymerase chain reaction (RT-PCR) testing. Hence most EDs, including our own, were dependent on rapid influenza diagnostic tests (RIDTs) for swine influenza. A positive rapid influenza A test was usually predictive of RT-PCR H1N1 positivity, but the rapid influenza A screening test (QuickVue A/B) was associated with 30% false negatives. The inability to rely on RIDTs for H1N1 diagnosis resulted in underdiagnosing H1N1. Confronted with adults admitted with ILIs, negative RIDTs, and restricted RT-PCR testing, there was a critical need to develop clinical criteria to diagnose probable swine influenza H1N1 pneumonia. During the pandemic, the Infectious Disease Division at Winthrop-University Hospital developed clinical criteria for adult admitted patients with ILIs and negative RIDTs. Similar to the one developed for the clinical diagnosis of legionnaire's disease. The Winthrop-University Hospital Infectious Disease Division's diagnostic weighted point score system for swine influenza H1N1 pneumonia is based on key clinical and

  18. Molecular evolution of H1N1 swine influenza in Guangdong, China, 2016-2017.

    PubMed

    Cai, Mengkai; Huang, Junming; Bu, Dexin; Yu, Zhiqing; Fu, Xinliang; Ji, Chihai; Zhou, Pei; Zhang, Guihong

    2018-06-01

    Swine are the main host of the H1N1 swine influenza virus (SIV), however, H1N1 can also infect humans and occasionally cause serious respiratory disease. To trace the evolution of the SIV in Guangdong, China, we performed an epidemic investigation during the period of 2016-2017. Nine H1N1 influenza viruses were isolated from swine nasal swabs. Antigenic analysis revealed that these viruses belonged to two distinct antigenic groups, represented by A/Swine/Guangdong/101/2016 and A/Swine/Guangdong/52/2017. Additionally, three genotypes, known as GD52/17-like, GD493/17-like and GD101/16-like, were identified by phylogenetic analysis. Importantly, the genotypes including a minimum of 4 pdm/09-origin internal genes have become prevalent in China in recent years. A total of 2966 swine serum samples were used to perform hemagglutination inhibition (HI) tests, and the results showed that the seroprevalence values of SW/GD/101/16 (32.2% in 2016, 32.1% in 2017) were significantly higher than the seroprevalence values of SW/GD/52/17 (18.0% in 2016, 16.7% in 2017). Our study showed that the three reassortant genotypes of H1N1 SIV currently circulating in China are stable, but H1N1pdm09 poses challenges to human health by the introduction of internal genes into these reassortant genotypes. Strengthening SIV surveillance is therefore critical for SIV control and minimizing its potential threat to public health. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Continual Reintroduction of Human Pandemic H1N1 Influenza A Viruses into Swine in the United States, 2009 to 2014

    PubMed Central

    Stratton, Jered; Killian, Mary Lea; Janas-Martindale, Alicia; Vincent, Amy L.

    2015-01-01

    ABSTRACT The diversity of influenza A viruses in swine (swIAVs) presents an important pandemic threat. Knowledge of the human-swine interface is particularly important for understanding how viruses with pandemic potential evolve in swine hosts. Through phylogenetic analysis of contemporary swIAVs in the United States, we demonstrate that human-to-swine transmission of pandemic H1N1 (pH1N1) viruses has occurred continuously in the years following the 2009 H1N1 pandemic and has been an important contributor to the genetic diversity of U.S. swIAVs. Although pandemic H1 and N1 segments had been largely removed from the U.S. swine population by 2013 via reassortment with other swIAVs, these antigens reemerged following multiple human-to-swine transmission events during the 2013-2014 seasonal epidemic. These findings indicate that the six internal gene segments from pH1N1 viruses are likely to be sustained long term in the U.S. swine population, with periodic reemergence of pandemic hemagglutinin (HA) and neuraminidase (NA) segments in association with seasonal pH1N1 epidemics in humans. Vaccinating U.S. swine workers may reduce infection of both humans and swine and in turn limit the role of humans as sources of influenza virus diversity in pigs. IMPORTANCE Swine are important hosts in the evolution of influenza A viruses with pandemic potential. Here, we analyze influenza virus sequence data generated by the U.S. Department of Agriculture's national surveillance system to identify the central role of humans in the reemergence of pandemic H1N1 (pH1N1) influenza viruses in U.S. swine herds in 2014. These findings emphasize the important role of humans as continuous sources of influenza virus diversity in swine and indicate that influenza viruses with pandemic HA and NA segments are likely to continue to reemerge in U.S. swine in association with seasonal pH1N1 epidemics in humans. PMID:25833052

  20. Continual Reintroduction of Human Pandemic H1N1 Influenza A Viruses into Swine in the United States, 2009 to 2014.

    PubMed

    Nelson, Martha I; Stratton, Jered; Killian, Mary Lea; Janas-Martindale, Alicia; Vincent, Amy L

    2015-06-01

    The diversity of influenza A viruses in swine (swIAVs) presents an important pandemic threat. Knowledge of the human-swine interface is particularly important for understanding how viruses with pandemic potential evolve in swine hosts. Through phylogenetic analysis of contemporary swIAVs in the United States, we demonstrate that human-to-swine transmission of pandemic H1N1 (pH1N1) viruses has occurred continuously in the years following the 2009 H1N1 pandemic and has been an important contributor to the genetic diversity of U.S. swIAVs. Although pandemic H1 and N1 segments had been largely removed from the U.S. swine population by 2013 via reassortment with other swIAVs, these antigens reemerged following multiple human-to-swine transmission events during the 2013-2014 seasonal epidemic. These findings indicate that the six internal gene segments from pH1N1 viruses are likely to be sustained long term in the U.S. swine population, with periodic reemergence of pandemic hemagglutinin (HA) and neuraminidase (NA) segments in association with seasonal pH1N1 epidemics in humans. Vaccinating U.S. swine workers may reduce infection of both humans and swine and in turn limit the role of humans as sources of influenza virus diversity in pigs. Swine are important hosts in the evolution of influenza A viruses with pandemic potential. Here, we analyze influenza virus sequence data generated by the U.S. Department of Agriculture's national surveillance system to identify the central role of humans in the reemergence of pandemic H1N1 (pH1N1) influenza viruses in U.S. swine herds in 2014. These findings emphasize the important role of humans as continuous sources of influenza virus diversity in swine and indicate that influenza viruses with pandemic HA and NA segments are likely to continue to reemerge in U.S. swine in association with seasonal pH1N1 epidemics in humans. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. Comparative Pathogenesis of an Avian H5N2 and a Swine H1N1 Influenza Virus in Pigs

    PubMed Central

    De Vleeschauwer, Annebel; Atanasova, Kalina; Van Borm, Steven; van den Berg, Thierry; Rasmussen, Thomas Bruun; Uttenthal, Åse; Van Reeth, Kristien

    2009-01-01

    Pigs are considered intermediate hosts for the transmission of avian influenza viruses (AIVs) to humans but the basic organ pathogenesis of AIVs in pigs has been barely studied. We have used 42 four-week-old influenza naive pigs and two different inoculation routes (intranasal and intratracheal) to compare the pathogenesis of a low pathogenic (LP) H5N2 AIV with that of an H1N1 swine influenza virus. The respiratory tract and selected extra-respiratory tissues were examined for virus replication by titration, immunofluorescence and RT-PCR throughout the course of infection. Both viruses caused a productive infection of the entire respiratory tract and epithelial cells in the lungs were the major target. Compared to the swine virus, the AIV produced lower virus titers and fewer antigen positive cells at all levels of the respiratory tract. The respiratory part of the nasal mucosa in particular showed only rare AIV positive cells and this was associated with reduced nasal shedding of the avian compared to the swine virus. The titers and distribution of the AIV varied extremely between individual pigs and were strongly affected by the route of inoculation. Gross lung lesions and clinical signs were milder with the avian than with the swine virus, corresponding with lower viral loads in the lungs. The brainstem was the single extra-respiratory tissue found positive for virus and viral RNA with both viruses. Our data do not reject the theory of the pig as an intermediate host for AIVs, but they suggest that AIVs need to undergo genetic changes to establish full replication potential in pigs. From a biomedical perspective, experimental LP H5 AIV infection of pigs may be useful to examine heterologous protection provided by H5 vaccines or other immunization strategies, as well as for further studies on the molecular pathogenesis and neurotropism of AIVs in mammals. PMID:19684857

  2. [An overview on swine influenza viruses].

    PubMed

    Yang, Shuai; Zhu, Wen-Fei; Shu, Yue-Long

    2013-05-01

    Swine influenza viruses (SIVs) are respiratory pathogens of pigs. They cause both economic bur den in livestock-dependent industries and serious global public health concerns in humans. Because of their dual susceptibility to human and avian influenza viruses, pigs are recognized as intermediate hosts for genetic reassortment and interspecies transmission. Subtypes H1N1, H1N2, and H3N2 circulate in swine populations around the world, with varied origin and genetic characteristics among different continents and regions. In this review, the role of pigs in evolution of influenza A viruses, the genetic evolution of SIVs and interspecies transmission of SIVs are described. Considering the possibility that pigs might produce novel influenza viruses causing more outbreaks and pandemics, routine epidemiological surveillance of influenza viruses in pig populations is highly recommended.

  3. Triple-reassortant influenza A virus with H3 of human seasonal origin, NA of swine origin, and internal A(H1N1) pandemic 2009 genes is established in Danish pigs.

    PubMed

    Krog, Jesper Schak; Hjulsager, Charlotte Kristiane; Larsen, Michael Albin; Larsen, Lars Erik

    2017-05-01

    This report describes a triple-reassortant influenza A virus with a HA that resembles H3 of human seasonal influenza from 2004 to 2005, N2 from influenza A virus already established in swine, and the internal gene cassette from A(H1N1)pdm09 has spread in Danish pig herds. The virus has been detected in several Danish pig herds during the last 2-3 years and may possess a challenge for human as well as animal health. © 2017 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  4. Avian-like A (H1N1) swine influenza virus antibodies among swine farm residents and pigs in southern China.

    PubMed

    Zhou, Han; Cao, Zhenpeng; Tan, Likai; Fu, Xinliang; Lu, Gang; Qi, Wenbao; Ke, Changwen; Wang, Heng; Sun, Lingshuang; Zhang, Guihong

    2014-01-01

    Infection of human with avian-like A (H1N1) swine influenza virus (SIV) occasionally occurs in China, suggesting a potential risk of cross-species transmission of the swine influenza H1N1 virus from pigs to humans, particularly to those having direct contact with pigs. A seroepidemiological study was conducted to assess the prevalence of antibodies against the avian-like A (H1N1) SIV among swine farm residents and pigs in southern China to evaluate the risk of infection to swine farm workers. Hemagglutination inhibition (HI) assays revealed that 11.17% (61/546) of the sera samples from swine farm residents in southern China were positive for antibodies against the avian-like A (H1N1) SIV. The difference in numbers of antibody-positive samples obtained from swine farm residents and a control group of healthy city residents was statistically significant (P = 0.031). In addition, 219 of the 1,180 serum samples from pigs were positive for the antibodies against an avian-like A (H1N1) SIV, A/swine/Guangdong/SS1/2013(H1N1), as assessed by HI. The data suggest that occupational exposure of swine farm residents and veterinarians in southern China to pigs may increase their risk of acquiring avian-like A (H1N1) SIV infection. According to a special pig farming model in southern China, the staff and residents are in close contact with infected pigs and may be among the first to become infected.

  5. A Novel H1N2 Influenza Virus Related to the Classical and Human Influenza Viruses from Pigs in Southern China.

    PubMed

    Song, Yafen; Wu, Xiaowei; Wang, Nianchen; Ouyang, Guowen; Qu, Nannan; Cui, Jin; Qi, Yan; Liao, Ming; Jiao, Peirong

    2016-01-01

    Southern China has long been considered to be an epicenter of pandemic influenza viruses. The special environment, breeding mode, and lifestyle in southern China provides more chances for wild aquatic birds, domestic poultry, pigs, and humans to be in contact. This creates the opportunity for interspecies transmission and generation of new influenza viruses. In this study, we reported a novel reassortant H1N2 influenza virus from pigs in southern China. According to the phylogenetic trees and homology of the nucleotide sequence, the virus was confirmed to be a novel triple-reassortant H1N2 virus containing genes from classical swine (PB2, PB1, HA, NP, and NS genes), triple-reassortant swine (PA and M genes), and recent human (NA gene) lineages. It indicated that the novel reassortment virus among human and swine influenza viruses occurred in pigs in southern China. The isolation of the novel reassortant H1N2 influenza viruses provides further evidence that pigs are "mixing vessels," and swine influenza virus surveillance in southern China will provide important information about genetic evaluation and antigenic variation of swine influenza virus to formulate the prevention and control measures for the viruses.

  6. Divergent human origin influenza viruses detected in Australian swine populations.

    PubMed

    Wong, Frank Y K; Donato, Celeste; Deng, Yi-Mo; Teng, Don; Komadina, Naomi; Baas, Chantal; Modak, Joyanta; O'Dea, Mark; Smith, David W; Effler, Paul V; Cooke, Julie; Davies, Kelly R; Hurt, Aeron; Kung, Nina; Levy, Avram; Loh, Richmond; Shan, Songhua; Shinwari, Mustaghfira W; Stevens, Vittoria; Taylor, Joanne; Williams, David T; Watson, James; Eagles, Debbie; McCullough, Sam; Barr, Ian G; Dhanasekaran, Vijaykrishna

    2018-06-06

    Global swine populations infected with influenza A viruses pose a persistent pandemic risk. With the exception of a few countries, our understanding of the genetic diversity of swine influenza viruses is limited, hampering control measures and pandemic risk assessment. Here we report the genomic characteristics and evolutionary history of influenza A viruses isolated in Australia during 2012-2016 from two geographically isolated swine populations in the states of Queensland and Western Australia. Phylogenetic analysis with an expansive human and swine influenza virus dataset comprising >40,000 sequences sampled globally, revealed evidence of the pervasive introduction and long-term establishment of gene segments derived from several human influenza viruses of past seasons, including H1N1/1977, H1N1/1995, H3N2/1968, H3N2/2003, and H1N1pdm09, and a genotype that contained gene segments derived from the past three pandemics (1968, re-emerged 1977 and 2009). Of the six human-derived gene lineages only one comprising two viruses isolated in Queensland during 2012 was closely related to swine viruses detected from other regions, indicating a previously undetected circulation of Australian swine lineages for approximately 3-44 years. Although the date of introduction of these lineages into Australian swine populations could not be accurately ascertained, we found evidence of sustained transmission of two lineages in swine during 2012-2016. The continued detection of human-origin influenza virus lineages in swine over several decades with little or unpredictable antigenic drift indicates that isolated swine populations can act as 'antigenic archives' of human influenza, raising the risk of re-emergence in humans when sufficient susceptible populations arise. IMPORTANCE We described the evolutionary origins and antigenic properties of influenza A viruses isolated from two separate Australian swine populations during 2012-2016, showing that these viruses were distinct to

  7. Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis

    PubMed Central

    Shi, Jian; Wang, Ruifang; Sun, Xin; Liu, Xiaokun; Zhao, Lianzhong; Jin, Meilin

    2015-01-01

    Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine–cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion. PMID:25906258

  8. Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis.

    PubMed

    Lin, Xian; Huang, Canhui; Shi, Jian; Wang, Ruifang; Sun, Xin; Liu, Xiaokun; Zhao, Lianzhong; Jin, Meilin

    2015-01-01

    Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine-cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion.

  9. Global transmission of influenza viruses from humans to swine

    PubMed Central

    Gramer, Marie R.; Vincent, Amy L.; Holmes, Edward C.

    2012-01-01

    To determine the extent to which influenza viruses jump between human and swine hosts, we undertook a large-scale phylogenetic analysis of pandemic A/H1N1/09 (H1N1pdm09) influenza virus genome sequence data. From this, we identified at least 49 human-to-swine transmission events that occurred globally during 2009–2011, thereby highlighting the ability of the H1N1pdm09 virus to transmit repeatedly from humans to swine, even following adaptive evolution in humans. Similarly, we identified at least 23 separate introductions of human seasonal (non-pandemic) H1 and H3 influenza viruses into swine globally since 1990. Overall, these results reveal the frequency with which swine are exposed to human influenza viruses, indicate that humans make a substantial contribution to the genetic diversity of influenza viruses in swine, and emphasize the need to improve biosecurity measures at the human–swine interface, including influenza vaccination of swine workers. PMID:22791604

  10. Phylogenetic analysis of swine influenza viruses recently isolated in Korea.

    PubMed

    Lee, C S; Kang, B K; Kim, H K; Park, S J; Park, B K; Jung, K; Song, D S

    2008-10-01

    Several influenza A viral subtypes were isolated from pigs during a severe outbreak of respiratory disease in Korea during 2005 and 2006. They included a classical swine H1N1 subtype, two swine-human-avian triple-recombinant H1N2 subtypes, and a swine-human-avian triple-recombinant H3N2 subtype. In the current study, genetic characterization to determine the probable origin of these recent isolates was carried out for the first time. Phylogenetic analysis indicated that all the recent Korean isolates of H1N1, H1N2, and H3N2 influenza are closely related to viruses from the United States. Serologic and genetic analysis indicated that the Korean H1N2 viral subtypes were introduced directly from the United States, and did not arise from recombination between Korean H1N1 and H3N2. We suggest that the H1N1, H1N2, and H3N2 viral subtypes that were isolated from the Korean swine population originated in North America, and that these viruses are currently circulating in the Korean swine population.

  11. Estimating reassortment rates in co-circulating Eurasian swine influenza viruses

    PubMed Central

    Baillie, G.; Coulter, E.; Bhatt, S.; Kellam, P.; McCauley, J. W.; Wood, J. L. N.; Brown, I. H.; Pybus, O. G.; Leigh Brown, A. J.

    2012-01-01

    Swine have often been considered as a mixing vessel for different influenza strains. In order to assess their role in more detail, we undertook a retrospective sequencing study to detect and characterize the reassortants present in European swine and to estimate the rate of reassortment between H1N1, H1N2 and H3N2 subtypes with Eurasian (avian-like) internal protein-coding segments. We analysed 69 newly obtained whole genome sequences of subtypes H1N1–H3N2 from swine influenza viruses sampled between 1982 and 2008, using Illumina and 454 platforms. Analyses of these genomes, together with previously published genomes, revealed a large monophyletic clade of Eurasian swine-lineage polymerase segments containing H1N1, H1N2 and H3N2 subtypes. We subsequently examined reassortments between the haemagglutinin and neuraminidase segments and estimated the reassortment rates between lineages using a recently developed evolutionary analysis method. High rates of reassortment between H1N2 and H1N1 Eurasian swine lineages were detected in European strains, with an average of one reassortment every 23 years. This rapid reassortment results from co-circulating lineages in swine, and in consequence we should expect further reassortments between currently circulating swine strains and the recent swine-origin H1N1v pandemic strain. PMID:22971819

  12. Evidence of reassortment of pandemic H1N1 influenza virus in swine in Argentina: are we facing the expansion of potential epicenters of influenza emergence?

    PubMed Central

    Pereda, Ariel; Rimondi, Agustina; Cappuccio, Javier; Sanguinetti, Ramon; Angel, Matthew; Ye, Jianqiang; Sutton, Troy; Dibárbora, Marina; Olivera, Valeria; Craig, Maria I.; Quiroga, Maria; Machuca, Mariana; Ferrero, Andrea; Perfumo, Carlos; Perez, Daniel R.

    2011-01-01

    Please cite this paper as: Pereda et al. (2011) Evidence of reassortment of pandemic H1N1 influenza virus in swine in Argentina: are we facing the expansion of potential epicenters of influenza emergence? Influenza and Other Respiratory Viruses 5(6), 409–412. In this report, we describe the occurrence of two novel swine influenza viruses (SIVs) in pigs in Argentina. These viruses are the result of two independent reassortment events between the H1N1 pandemic influenza virus (H1N1pdm) and human‐like SIVs, showing the constant evolution of influenza viruses at the human–swine interface and the potential health risk of H1N1pdm as it appears to be maintained in the swine population. It must be noted that because of the lack of information regarding the circulation of SIVs in South America, we cannot discard the possibility that ancestors of the H1N1pdm or other SIVs have been present in this part of the world. More importantly, these findings suggest an ever‐expanding geographic range of potential epicenters of influenza emergence with public health risks. PMID:21668680

  13. Seroprotective antibodies to 2011 variant influenza A(H3N2v) and seasonal influenza A(H3N2) among three age groups of US Department of Defense service members.

    PubMed

    Radin, Jennifer M; Hawksworth, Anthony W; Ortiguerra, Ryan G; Brice, Gary T

    2015-01-01

    In 2011, a new variant of influenza A(H3N2) emerged that contained a recombination of genes from swine H3N2 viruses and the matrix (M) gene of influenza A(H1N1)pdm09 virus. New combinations and variants of pre-existing influenza viruses are worrisome if there is low or nonexistent immunity in a population, which increases chances for an outbreak or pandemic. Sera collected in 2011 were obtained from US Department of Defense service members in three age groups: 19-21 years, 32-33 years, and 47-48 years. Pre- and post-vaccination samples were available for the youngest age group, and postvaccination samples for the two older groups. Specimens were tested using microneutralization assays for antibody titers against H3N2v (A/Indiana/10/2011) and seasonal H3N2 virus (A/Perth/16/2009). The youngest age group had significantly (p<0.05) higher geometric mean titers for H3N2v with 165 (95% confidence interval [CI]: 105-225) compared with the two older groups, aged 32-33 and 47-48 years, who had geometric mean titers of 68 (95% CI: 55-82) and 46 (95% CI: 24-65), respectively. Similarly, the youngest age group also had the highest geometric mean titers for seasonal H3N2. In the youngest age group, the proportion of patients who seroconverted after vaccination was 12% for H3N2v and 27% for seasonal H3N2. Our results were similar to previous studies that found highest seroprotection among young adults and decreasing titers among older adults. The proportion of 19- to 21-year-olds who seroconverted after seasonal vaccination was low and similar to previous findings. Improving our understanding of H3N2v immunity among different age groups in the United States can help inform vaccination plans if H3N2v becomes more transmissible in the future.

  14. SWINE INFLUENZA

    PubMed Central

    Lewis, Paul A.; Shope, Richard E.

    1931-01-01

    1. A hemophilic bacillus has been regularly obtained in culture from the respiratory tract of a series of swine experimentally infected with swine influenza and from a small number of spontaneous field cases of the disease. It has not been observed in respiratory tract cultures from a group of swine free from influenza. 2. The cultural and morphological characters of the organism have been described and the name Hemophilus influenzas (variety suis) suggested. The organism exhibits marked serological diversity, since only two out of eight strains studied were serologically identical. It is usually non-pathogenic for rabbits and white rats, and irregularly pathogenic for white mice. One strain of the organism was pathogenic for guinea pigs while two others were not. 3. Eleven out of thirteen attempts to induce symptoms of disease in swine by intranasal inoculation with pure cultures of H. influenzae suis were entirely negative. The remaining two attempts which suggested a positive result have been discussed. 4. Attention has been called to the marked similarity which exists between non-indol-producing strains of H. influenzae and H. influenzae suis. PMID:19869923

  15. Amino Acids in Hemagglutinin Antigenic Site B Determine Antigenic and Receptor Binding Differences between A(H3N2)v and Ancestral Seasonal H3N2 Influenza Viruses

    PubMed Central

    Wang, Xiaoquan; Ilyushina, Natalia A.; Lugovtsev, Vladimir Y.; Bovin, Nicolai V.; Couzens, Laura K.; Gao, Jin

    2016-01-01

    ABSTRACT Influenza A H3N2 variant [A(H3N2)v] viruses, which have caused human infections in the United States in recent years, originated from human seasonal H3N2 viruses that were introduced into North American swine in the mid-1990s, but they are antigenically distinct from both the ancestral and current circulating H3N2 strains. A reference A(H3N2)v virus, A/Minnesota/11/2010 (MN/10), and a seasonal H3N2 strain, A/Beijing/32/1992 (BJ/92), were chosen to determine the molecular basis for the antigenic difference between A(H3N2)v and the ancestral viruses. Viruses containing wild-type and mutant MN/10 or BJ/92 hemagglutinins (HAs) were constructed and probed for reactivity with ferret antisera against MN/10 and BJ/92 in hemagglutination inhibition assays. Among the amino acids that differ between the MN/10 and BJ/92 HAs, those in antigenic site A had little impact on the antigenic phenotype. Within antigenic site B, mutations at residues 156, 158, 189, and 193 of MN/10 HA to those in BJ/92 switched the MN/10 antigenic phenotype to that of BJ/92. Mutations at residues 156, 157, 158, 189, and 193 of BJ/92 HA to amino acids present in MN/10 were necessary for BJ/92 to become antigenically similar to MN/10. The HA amino acid substitutions responsible for switching the antigenic phenotype also impacted HA binding to sialyl receptors that are usually present in the human respiratory tract. Our study demonstrates that antigenic site B residues play a critical role in determining both the unique antigenic phenotype and receptor specificity of A(H3N2)v viruses, a finding that may facilitate future surveillance and risk assessment of novel influenza viruses. IMPORTANCE Influenza A H3N2 variant [A(H3N2)v] viruses have caused hundreds of human infections in multiple states in the United States since 2009. Most cases have been children who had contact with swine in agricultural fairs. These viruses originated from human seasonal H3N2 viruses that were introduced into the U

  16. A Novel H1N2 Influenza Virus Related to the Classical and Human Influenza Viruses from Pigs in Southern China

    PubMed Central

    Song, Yafen; Wu, Xiaowei; Wang, Nianchen; Ouyang, Guowen; Qu, Nannan; Cui, Jin; Qi, Yan; Liao, Ming; Jiao, Peirong

    2016-01-01

    Southern China has long been considered to be an epicenter of pandemic influenza viruses. The special environment, breeding mode, and lifestyle in southern China provides more chances for wild aquatic birds, domestic poultry, pigs, and humans to be in contact. This creates the opportunity for interspecies transmission and generation of new influenza viruses. In this study, we reported a novel reassortant H1N2 influenza virus from pigs in southern China. According to the phylogenetic trees and homology of the nucleotide sequence, the virus was confirmed to be a novel triple-reassortant H1N2 virus containing genes from classical swine (PB2, PB1, HA, NP, and NS genes), triple-reassortant swine (PA and M genes), and recent human (NA gene) lineages. It indicated that the novel reassortment virus among human and swine influenza viruses occurred in pigs in southern China. The isolation of the novel reassortant H1N2 influenza viruses provides further evidence that pigs are “mixing vessels,” and swine influenza virus surveillance in southern China will provide important information about genetic evaluation and antigenic variation of swine influenza virus to formulate the prevention and control measures for the viruses. PMID:27458456

  17. Protection of human influenza vaccines against a reassortant swine influenza virus of pandemic H1N1 origin using a pig model.

    PubMed

    Arunorat, Jirapat; Charoenvisal, Nataya; Woonwong, Yonlayong; Kedkovid, Roongtham; Jittimanee, Supattra; Sitthicharoenchai, Panchan; Kesdangsakonwut, Sawang; Poolperm, Pariwat; Thanawongnuwech, Roongroje

    2017-10-01

    Since the pandemic H1N1 emergence in 2009 (pdmH1N1), many reassortant pdmH1N1 viruses emerged and found circulating in the pig population worldwide. Currently, commercial human subunit vaccines are used commonly to prevent the influenza symptom based on the WHO recommendation. In case of current reassortant swine influenza viruses transmitting from pigs to humans, the efficacy of current human influenza vaccines is of interest. In this study, influenza A negative pigs were vaccinated with selected commercial human subunit vaccines and challenged with rH3N2. All sera were tested with both HI and SN assays using four representative viruses from the surveillance data in 2012 (enH1N1, pdmH1N1, rH1N2 and rH3N2). The results showed no significant differences in clinical signs and macroscopic and microscopic findings among groups. However, all pig sera from vaccinated groups had protective HI titers to the enH1N1, pdmH1N1 and rH1N2 at 21DPV onward and had protective SN titers only to pdmH1N1and rH1N2 at 21DPV onward. SN test results appeared more specific than those of HI tests. All tested sera had no cross-reactivity against the rH3N2. Both studied human subunit vaccines failed to protect and to stop viral shedding with no evidence of serological reaction against rH3N2. SIV surveillance is essential for monitoring a novel SIV emergence potentially for zoonosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. History of Swine influenza viruses in Asia.

    PubMed

    Zhu, Huachen; Webby, Richard; Lam, Tommy T Y; Smith, David K; Peiris, Joseph S M; Guan, Yi

    2013-01-01

    The pig is one of the main hosts of influenza A viruses and plays important roles in shaping the current influenza ecology. The occurrence of the 2009 H1N1 pandemic influenza virus demonstrated that pigs could independently facilitate the genesis of a pandemic influenza strain. Genetic analyses revealed that this virus was derived by reassortment between at least two parent swine influenza viruses (SIV), from the northern American triple reassortant H1N2 (TR) and European avian-like H1N1 (EA) lineages. The movement of live pigs between different continents and subsequent virus establishment are preconditions for such a reassortment event to occur. Asia, especially China, has the largest human and pig populations in the world, and seems to be the only region frequently importing pigs from other continents. Virological surveillance revealed that not only classical swine H1N1 (CS), and human-origin H3N2 viruses circulated, but all of the EA, TR and their reassortant variants were introduced into and co-circulated in pigs in this region. Understanding the long-term evolution and history of SIV in Asia would provide insights into the emergence of influenza viruses with epidemic potential in swine and humans.

  19. Identification of reassortant pandemic H1N1 influenza virus in Korean pigs.

    PubMed

    Han, Jae Yeon; Park, Sung Jun; Kim, Hye Kwon; Rho, Semi; Nguyen, Giap Van; Song, Daesub; Kang, Bo Kyu; Moon, Hyung Jun; Yeom, Min Joo; Park, Bong Kyun

    2012-05-01

    Since the 2009 pandemic human H1N1 influenza A virus emerged in April 2009, novel reassortant strains have been identified throughout the world. This paper describes the detection and isolation of reassortant strains associated with human pandemic influenza H1N1 and swine influenza H1N2 (SIV) viruses in swine populations in South Korea. Two influenza H1N2 reassortants were detected, and subtyped by PCR. The strains were isolated using Madin- Darby canine kidney (MDCK) cells, and genetically characterized by phylogenetic analysis for genetic diversity. They consisted of human, avian, and swine virus genes that were originated from the 2009 pandemic H1N1 virus and a neuraminidase (NA) gene from H1N2 SIV previously isolated in North America. This identification of reassortment events in swine farms raises concern that reassortant strains may continuously circulate within swine populations, calling for the further study and surveillance of pandemic H1N1 among swine.

  20. Frequent global transmission of H1N1pdm09 influenza viruses from humans to swine, 2009-2011

    USDA-ARS?s Scientific Manuscript database

    Using a large-scale phylogenetic approach we identify at least 52 human-to-swine transmission events of pandemic A/H1N1/09 influenza virus. These results highlight the global frequency of swine exposure to human influenza viruses and the permeability of the human-swine species barrier, even followin...

  1. Comparative virulence of wild-type H1N1pdm09 influenza A isolates in swine

    USDA-ARS?s Scientific Manuscript database

    In 2009, a novel swine-origin H1N1 (H1N1pdm09) influenza A virus (IAV) reached pandemic status and was soon after detected in pigs worldwide. The objective of this study was to evaluate whether differences in the HA protein can affect pathogenicity and antigenicity of H1N1pdm09 in swine. We compared...

  2. Isolation and genetic characterization of H5N2 influenza viruses from pigs in Korea.

    PubMed

    Lee, Jun Han; Pascua, Philippe Noriel Q; Song, Min-Suk; Baek, Yun Hee; Kim, Chul-Joong; Choi, Hwan-Woon; Sung, Moon-Hee; Webby, Richard J; Webster, Robert G; Poo, Haryoung; Choi, Young Ki

    2009-05-01

    Due to dual susceptibility to both human and avian influenza A viruses, pigs are believed to be effective intermediate hosts for the spread and production of new viruses with pandemic potential. In early 2008, two swine H5N2 viruses were isolated from our routine swine surveillance in Korea. The sequencing and phylogenetic analysis of surface proteins revealed that the Sw/Korea/C12/08 and Sw/Korea/C13/08 viruses were derived from avian influenza viruses of the Eurasian lineage. However, although the Sw/Korea/C12/08 isolate is an entirely avian-like virus, the Sw/Korea/C13/08 isolate is an avian-swine-like reassortant with the PB2, PA, NP, and M genes coming from a 2006 Korean swine H3N1-like virus. The molecular characterization of the two viruses indicated an absence of significant mutations that could be associated with virulence or binding affinity. However, animal experiments showed that the reassortant Sw/Korea/C13/08 virus was more adapted and was more readily transmitted than the purely avian-like virus in a swine experimental model but not in ferrets. Furthermore, seroprevalence in swine sera from 2006 to 2008 suggested that avian H5 viruses have been infecting swine since 2006. Although there are no known potential clinical implications of the avian-swine reassortant virus for pathogenicity in pigs or other species, including humans, at present, the efficient transmissibility of the swine-adapted H5N2 virus could facilitate virus spread and could be a potential model for pandemic, highly pathogenic avian influenza (e.g., H5N1 and H7N7) virus outbreaks or a pandemic strain itself.

  3. Investigation of an Outbreak of Variant Influenza A(H3N2) Virus Infection Associated With an Agricultural Fair-Ohio, August 2012.

    PubMed

    Greenbaum, Adena; Quinn, Celia; Bailer, Jennifer; Su, Su; Havers, Fiona; Durand, Lizette O; Jiang, Victoria; Page, Shannon; Budd, Jeremy; Shaw, Michael; Biggerstaff, Matthew; de Fijter, Sietske; Smith, Kathleen; Reed, Carrie; Epperson, Scott; Brammer, Lynnette; Feltz, Dave; Sohner, Kevin; Ford, Jared; Jain, Seema; Gargiullo, Paul; Weiss, Edward; Burg, Pat; DiOrio, Mary; Fowler, Brian; Finelli, Lyn; Jhung, Michael A

    2015-11-15

    In 2012, one third of cases in a multistate outbreak of variant influenza A(H3N2) virus ([H3N2]v) infection occurred in Ohio. We conducted an investigation of (H3N2)v cases associated with agricultural Fair A in Ohio. We surveyed Fair A swine exhibitors and their household members. Confirmed cases had influenza-like illness (ILI) and a positive laboratory test for (H3N2)v, and probable cases had ILI. We calculated attack rates. We determined risk factors for infection, using multivariable log-binomial regression. We identified 20 confirmed and 94 probable cases associated with Fair A. Among 114 cases, the median age was 10 years, there were no hospitalizations or deaths, and 82% had swine exposure. In the exhibitor household cohort of 359 persons (83 households), we identified 6 confirmed cases (2%) and 40 probable cases (11%). An age of <10 years was a significant risk factor (P < .01) for illness. One instance of likely human-to-human transmission was identified. In this (H3N2)v outbreak, no evidence of sustained human-to-human (H3N2)v transmission was found. Our risk factor analysis contributed to the development of the recommendation that people at increased risk of influenza-associated complications, including children aged <5 years, avoid swine barns at fairs during the 2012 fair season. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  4. Design and performance of the CDC real-time reverse transcriptase PCR swine flu panel for detection of 2009 A (H1N1) pandemic influenza virus.

    PubMed

    Shu, Bo; Wu, Kai-Hui; Emery, Shannon; Villanueva, Julie; Johnson, Roy; Guthrie, Erica; Berman, LaShondra; Warnes, Christine; Barnes, Nathelia; Klimov, Alexander; Lindstrom, Stephen

    2011-07-01

    Swine influenza viruses (SIV) have been shown to sporadically infect humans and are infrequently identified by the Influenza Division of the Centers for Disease Control and Prevention (CDC) after being received as unsubtypeable influenza A virus samples. Real-time reverse transcriptase PCR (rRT-PCR) procedures for detection and characterization of North American lineage (N. Am) SIV were developed and implemented at CDC for rapid identification of specimens from cases of suspected infections with SIV. These procedures were utilized in April 2009 for detection of human cases of 2009 A (H1N1) pandemic (pdm) influenza virus infection. Based on genetic sequence data derived from the first two viruses investigated, the previously developed rRT-PCR procedures were optimized to create the CDC rRT-PCR Swine Flu Panel for detection of the 2009 A (H1N1) pdm influenza virus. The analytical sensitivity of the CDC rRT-PCR Swine Flu Panel was shown to be 5 copies of RNA per reaction and 10(-1.3 - -0.7) 50% infectious doses (ID(50)) per reaction for cultured viruses. Cross-reactivity was not observed when testing human clinical specimens or cultured viruses that were positive for human seasonal A (H1N1, H3N2) and B influenza viruses. The CDC rRT-PCR Swine Flu Panel was distributed to public health laboratories in the United States and internationally from April 2009 until June 2010. The CDC rRT-PCR Swine Flu Panel served as an effective tool for timely and specific detection of 2009 A (H1N1) pdm influenza viruses and facilitated subsequent public health response implementation.

  5. Isolation and molecular characterization of an H5N1 swine influenza virus in China in 2015.

    PubMed

    Wu, Haibo; Yang, Fan; Lu, Rufeng; Xu, Lihua; Liu, Fumin; Peng, Xiuming; Wu, Nanping

    2018-03-01

    In 2015, an H5N1 influenza virus was isolated from a pig in Zhejiang Province, Eastern China. This strain was characterized by whole-genome sequencing with subsequent phylogenetic analysis. Phylogenetic analysis showed that all segments from this strain belonged to clade 2.3.2 and that it had received its genes from poultry influenza viruses in China. A Glu627Lys mutation associated with pathogenicity was observed in the PB2 protein. This strain was moderately pathogenic in mice and was able to replicate without prior adaptation. These results suggest that active surveillance of swine influenza should be used as an early warning system for influenza outbreaks in mammals.

  6. Avian influenza A (H5N1) virus antibodies in pigs and residents of swine farms, southern China.

    PubMed

    Cao, Nan; Zhu, Wanjun; Chen, Ye; Tan, Likai; Zhou, Pei; Cao, Zhenpeng; Ke, Changwen; Li, Yugu; Wu, Jie; Qi, Wenbao; Jiao, Peirong; Zhang, Guihong

    2013-12-01

    Since 1997, the H5 avian influenza viruses (AIVs) circulating in China have become an international concern. Clade 2.3.2 of H5N1 AIVs is genetically distinct from the viruses isolated before 2007 and antigenically different from the vaccine strains widely used in China. Swine farms in rural China are thought to play an important role in AIVs ecology. A seroepidemiological study was undertaken among swine farm residents and pigs to understand the prevalence of antibodies against H5N1 AIVs in southern China. During the period March 24, 2008 to December 25, 2012,serum samples were collected from 1606 swine farm residents on 40 swine farms in southern China. A total of 1980 pigs' serum samples were collected in the same swine farms where swine workers' serum samples were collected from March 2009 to March 2013. For a control group, 104 serum samples were collected from healthy city residents in Nanchang. All the serum samples were collected to perform hemagglutination inhibition (HI) and (neutralization) NT assays to investigate the prevalence of H5N1 AIV infections in southern China. Sixteen human samples were positive by HI assay and 10 of these were also positive by NT assay against H5N1. No serum samples from human control and pigs were HI positive for H5N1 AIV. Our results demonstrate minimal transmission H5N1 AIV from birds to pigs in the swine farms studied and the risk of poultry-to-human and poultry-to-pig transmission for at least clades 2.3.2 seemed very low. This study provides the first data regarding antibodies against H5N1 AIV in humans and pigs on swine farms in China. The findings of this study can serve as a baseline for additional serologic studies to assess transmission of H5N1 viruses between avian species, pigs and swine workers. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. H1N1 Swine Influenza Viruses Differ from Avian Precursors by a Higher pH Optimum of Membrane Fusion.

    PubMed

    Baumann, Jan; Kouassi, Nancy Mounogou; Foni, Emanuela; Klenk, Hans-Dieter; Matrosovich, Mikhail

    2016-02-01

    The H1N1 Eurasian avian-like swine (EAsw) influenza viruses originated from an avian H1N1 virus. To characterize potential changes in the membrane fusion activity of the hemagglutinin (HA) during avian-to-swine adaptation of the virus, we studied EAsw viruses isolated in the first years of their circulation in pigs and closely related contemporary H1N1 viruses of wild aquatic birds. Compared to the avian viruses, the swine viruses were less sensitive to neutralization by lysosomotropic agent NH4Cl in MDCK cells, had a higher pH optimum of hemolytic activity, and were less stable at acidic pH. Eight amino acid substitutions in the HA were found to separate the EAsw viruses from their putative avian precursor; four substitutions-T492S, N722D, R752K, and S1132F-were located in the structural regions of the HA2 subunit known to play a role in acid-induced conformational transition of the HA. We also studied low-pH-induced syncytium formation by cell-expressed HA proteins and found that the HAs of the 1918, 1957, 1968, and 2009 pandemic viruses required a lower pH for fusion induction than did the HA of a representative EAsw virus. Our data show that transmission of an avian H1N1 virus to pigs was accompanied by changes in conformational stability and fusion promotion activity of the HA. We conclude that distinctive host-determined fusion characteristics of the HA may represent a barrier for avian-to-swine and swine-to-human transmission of influenza viruses. Continuing cases of human infections with zoonotic influenza viruses highlight the necessity to understand which viral properties contribute to interspecies transmission. Efficient binding of the HA to cellular receptors in a new host species is known to be essential for the transmission. Less is known about required adaptive changes in the membrane fusion activity of the HA. Here we show that adaptation of an avian influenza virus to pigs in Europe in 1980s was accompanied by mutations in the HA, which decreased

  8. H1N1 Swine Influenza Viruses Differ from Avian Precursors by a Higher pH Optimum of Membrane Fusion

    PubMed Central

    Baumann, Jan; Kouassi, Nancy Mounogou; Foni, Emanuela; Klenk, Hans-Dieter

    2015-01-01

    ABSTRACT The H1N1 Eurasian avian-like swine (EAsw) influenza viruses originated from an avian H1N1 virus. To characterize potential changes in the membrane fusion activity of the hemagglutinin (HA) during avian-to-swine adaptation of the virus, we studied EAsw viruses isolated in the first years of their circulation in pigs and closely related contemporary H1N1 viruses of wild aquatic birds. Compared to the avian viruses, the swine viruses were less sensitive to neutralization by lysosomotropic agent NH4Cl in MDCK cells, had a higher pH optimum of hemolytic activity, and were less stable at acidic pH. Eight amino acid substitutions in the HA were found to separate the EAsw viruses from their putative avian precursor; four substitutions—T492S, N722D, R752K, and S1132F—were located in the structural regions of the HA2 subunit known to play a role in acid-induced conformational transition of the HA. We also studied low-pH-induced syncytium formation by cell-expressed HA proteins and found that the HAs of the 1918, 1957, 1968, and 2009 pandemic viruses required a lower pH for fusion induction than did the HA of a representative EAsw virus. Our data show that transmission of an avian H1N1 virus to pigs was accompanied by changes in conformational stability and fusion promotion activity of the HA. We conclude that distinctive host-determined fusion characteristics of the HA may represent a barrier for avian-to-swine and swine-to-human transmission of influenza viruses. IMPORTANCE Continuing cases of human infections with zoonotic influenza viruses highlight the necessity to understand which viral properties contribute to interspecies transmission. Efficient binding of the HA to cellular receptors in a new host species is known to be essential for the transmission. Less is known about required adaptive changes in the membrane fusion activity of the HA. Here we show that adaptation of an avian influenza virus to pigs in Europe in 1980s was accompanied by mutations in

  9. A human-like H1N2 influenza virus detected during an outbreak of acute respiratory disease in swine in Brazil.

    PubMed

    Schaefer, Rejane; Rech, Raquel Rubia; Gava, Danielle; Cantão, Mauricio Egídio; da Silva, Marcia Cristina; Silveira, Simone; Zanella, Janice Reis Ciacci

    2015-01-01

    Passive monitoring for detection of influenza A viruses (IAVs) in pigs has been carried out in Brazil since 2009, detecting mostly the A(H1N1)pdm09 influenza virus. Since then, outbreaks of acute respiratory disease suggestive of influenza A virus infection have been observed frequently in Brazilian pig herds. During a 2010-2011 influenza monitoring, a novel H1N2 influenza virus was detected in nursery pigs showing respiratory signs. The pathologic changes were cranioventral acute necrotizing bronchiolitis to subacute proliferative and purulent bronchointerstitial pneumonia. Lung tissue samples were positive for both influenza A virus and A(H1N1)pdm09 influenza virus based on RT-qPCR of the matrix gene. Two IAVs were isolated in SPF chicken eggs. HI analysis of both swine H1N2 influenza viruses showed reactivity to the H1δ cluster. DNA sequencing was performed for all eight viral gene segments of two virus isolates. According to the phylogenetic analysis, the HA and NA genes clustered with influenza viruses of the human lineage (H1-δ cluster, N2), whereas the six internal gene segments clustered with the A(H1N1)pdm09 group. This is the first report of a reassortant human-like H1N2 influenza virus derived from pandemic H1N1 virus causing an outbreak of respiratory disease in pigs in Brazil. The emergence of a reassortant IAV demands the close monitoring of pigs through the full-genome sequencing of virus isolates in order to enhance genetic information about IAVs circulating in pigs.

  10. Genetic characterization of H1N2 influenza a virus isolated from sick pigs in Southern China in 2010.

    PubMed

    Kong, Wei Li; Huang, Liang Zong; Qi, Hai Tao; Cao, Nan; Zhang, Liang Quan; Wang, Heng; Guan, Shang Song; Qi, Wen Bao; Jiao, Pei Rong; Liao, Ming; Zhang, Gui Hong

    2011-10-13

    In China H3N2 and H1N1 swine influenza viruses have been circulating for many years. In January 2010, before swine were infected with foot and mouth disease in Guangdong, some pigs have shown flu-like symptoms: cough, sneeze, runny nose and fever. We collected the nasopharyngeal swab of all sick pigs as much as possible. One subtype H1N2 influenza viruses were isolated from the pig population. The complete genome of one isolate, designated A/swine/Guangdong/1/2010(H1N2), was sequenced and compared with sequences available in GenBank. The nucleotide sequences of all eight viral RNA segments were determined, and then phylogenetic analysis was performed using the neighbor-joining method. HA, NP, M and NS were shown to be closely to swine origin. PB2 and PA were close to avian origin, but NA and PB1were close to human origin. It is a result of a multiple reassortment event. In conclusion, our finding provides further evidence about the interspecies transmission of avian influenza viruses to pigs and emphasizes the importance of reinforcing swine influenza virus (SIV) surveillance, especially before the emergence of highly pathogenic FMDs in pigs in Guangdong.

  11. Effect of serial pig passages on the adaptation of an avian H9N2 influenza virus to swine.

    PubMed

    Mancera Gracia, Jose Carlos; Van den Hoecke, Silvie; Saelens, Xavier; Van Reeth, Kristien

    2017-01-01

    H9N2 avian influenza viruses are endemic in poultry in Asia and the Middle East. These viruses sporadically cause dead-end infections in pigs and humans raising concerns about their potential to adapt to mammals or reassort with human or swine influenza viruses. We performed ten serial passages with an avian H9N2 virus (A/quail/Hong Kong/G1/1997) in influenza naïve pigs to assess the potential of this virus to adapt to swine. Virus replication in the entire respiratory tract and nasal virus excretion were examined after each passage and we deep sequenced viral genomic RNA of the parental and passage four H9N2 virus isolated from the nasal mucosa and lung. The parental H9N2 virus caused a productive infection in pigs with a predominant tropism for the nasal mucosa, whereas only 50% lung samples were virus-positive. In contrast, inoculation of pigs with passage four virus resulted in viral replication in the entire respiratory tract. Subsequent passages were associated with reduced virus replication in the lungs and infectious virus was no longer detectable in the upper and lower respiratory tract of inoculated pigs at passage ten. The broader tissue tropism after four passages was associated with an amino acid residue substitution at position 225, within the receptor-binding site of the hemagglutinin. We also compared the parental H9N2, passage four H9N2 and the 2009 pandemic H1N1 (pH1N1) virus in a direct contact transmission experiment. Whereas only one out of six contact pigs showed nasal virus excretion of the wild-type H9N2 for more than four days, all six contact animals shed the passage four H9N2 virus. Nevertheless, the amount of excreted virus was significantly lower when compared to that of the pH1N1, which readily transmitted and replicated in all six contact animals. Our data demonstrate that serial passaging of H9N2 virus in pigs enhances its replication and transmissibility. However, full adaptation of an avian H9N2 virus to pigs likely requires an

  12. Effect of serial pig passages on the adaptation of an avian H9N2 influenza virus to swine

    PubMed Central

    Van den Hoecke, Silvie; Saelens, Xavier; Van Reeth, Kristien

    2017-01-01

    H9N2 avian influenza viruses are endemic in poultry in Asia and the Middle East. These viruses sporadically cause dead-end infections in pigs and humans raising concerns about their potential to adapt to mammals or reassort with human or swine influenza viruses. We performed ten serial passages with an avian H9N2 virus (A/quail/Hong Kong/G1/1997) in influenza naïve pigs to assess the potential of this virus to adapt to swine. Virus replication in the entire respiratory tract and nasal virus excretion were examined after each passage and we deep sequenced viral genomic RNA of the parental and passage four H9N2 virus isolated from the nasal mucosa and lung. The parental H9N2 virus caused a productive infection in pigs with a predominant tropism for the nasal mucosa, whereas only 50% lung samples were virus-positive. In contrast, inoculation of pigs with passage four virus resulted in viral replication in the entire respiratory tract. Subsequent passages were associated with reduced virus replication in the lungs and infectious virus was no longer detectable in the upper and lower respiratory tract of inoculated pigs at passage ten. The broader tissue tropism after four passages was associated with an amino acid residue substitution at position 225, within the receptor-binding site of the hemagglutinin. We also compared the parental H9N2, passage four H9N2 and the 2009 pandemic H1N1 (pH1N1) virus in a direct contact transmission experiment. Whereas only one out of six contact pigs showed nasal virus excretion of the wild-type H9N2 for more than four days, all six contact animals shed the passage four H9N2 virus. Nevertheless, the amount of excreted virus was significantly lower when compared to that of the pH1N1, which readily transmitted and replicated in all six contact animals. Our data demonstrate that serial passaging of H9N2 virus in pigs enhances its replication and transmissibility. However, full adaptation of an avian H9N2 virus to pigs likely requires an

  13. Are Swine Workers in the United States at Increased Risk of Infection with Zoonotic Influenza Virus?

    PubMed Central

    Myers, Kendall P.; Olsen, Christopher W.; Setterquist, Sharon F.; Capuano, Ana W.; Donham, Kelley J.; Thacker, Eileen L.; Merchant, James A.; Gray, Gregory C.

    2006-01-01

    Background Pandemic influenza strains originate in nonhuman species. Pigs have an important role in interspecies transmission of the virus. We examined multiple swine-exposed human populations in the nation's number 1 swine-producing state for evidence of previous swine influenza virus infection. Methods We performed controlled, cross-sectional seroprevalence studies among 111 farmers, 97 meat processing workers, 65 veterinarians, and 79 control subjects using serum samples collected during the period of 2002–2004. Serum samples were tested using a hemagglutination inhibition assay against the following 6 influenza A virus isolates collected recently from pigs and humans: A/Swine/WI/238/97 (H1N1), A/Swine/WI/R33F/01 (H1N2), A/Swine/Minnesota/593/99 (H3N2), A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2), and A/Nanchang/933/95 (H3N2). Results Using multivariable proportional odds modeling, all 3 exposed study groups demonstrated markedly elevated titers against the H1N1 and H1N2 swine influenza virus isolates, compared with control subjects. Farmers had the strongest indication of exposure to swine H1N1 virus infection (odds ratio [OR], 35.3; 95% confidence interval [CI], 7.7–161.8), followed by veterinarians (OR, 17.8; 95% CI, 3.8–82.7), and meat processing workers (OR, 6.5; 95% CI, 1.4–29.5). Similarly, farmers had the highest odds for exposure to swine H1N2 virus (OR, 13.8; 95% CI, 5.4–35.4), followed by veterinarians (OR, 9.5; 95% CI, 3.6–24.6) and meat processing workers (OR, 2.7; 95% CI, 1.1–6.7). Conclusions Occupational exposure to pigs greatly increases workers' risk of swine influenza virus infection. Swine workers should be included in pandemic surveillance and in antiviral and immunization strategies. PMID:16323086

  14. Design and Performance of the CDC Real-Time Reverse Transcriptase PCR Swine Flu Panel for Detection of 2009 A (H1N1) Pandemic Influenza Virus▿†‡

    PubMed Central

    Shu, Bo; Wu, Kai-Hui; Emery, Shannon; Villanueva, Julie; Johnson, Roy; Guthrie, Erica; Berman, LaShondra; Warnes, Christine; Barnes, Nathelia; Klimov, Alexander; Lindstrom, Stephen

    2011-01-01

    Swine influenza viruses (SIV) have been shown to sporadically infect humans and are infrequently identified by the Influenza Division of the Centers for Disease Control and Prevention (CDC) after being received as unsubtypeable influenza A virus samples. Real-time reverse transcriptase PCR (rRT-PCR) procedures for detection and characterization of North American lineage (N. Am) SIV were developed and implemented at CDC for rapid identification of specimens from cases of suspected infections with SIV. These procedures were utilized in April 2009 for detection of human cases of 2009 A (H1N1) pandemic (pdm) influenza virus infection. Based on genetic sequence data derived from the first two viruses investigated, the previously developed rRT-PCR procedures were optimized to create the CDC rRT-PCR Swine Flu Panel for detection of the 2009 A (H1N1) pdm influenza virus. The analytical sensitivity of the CDC rRT-PCR Swine Flu Panel was shown to be 5 copies of RNA per reaction and 10−1.3∼−0.7 50% infectious doses (ID50) per reaction for cultured viruses. Cross-reactivity was not observed when testing human clinical specimens or cultured viruses that were positive for human seasonal A (H1N1, H3N2) and B influenza viruses. The CDC rRT-PCR Swine Flu Panel was distributed to public health laboratories in the United States and internationally from April 2009 until June 2010. The CDC rRT-PCR Swine Flu Panel served as an effective tool for timely and specific detection of 2009 A (H1N1) pdm influenza viruses and facilitated subsequent public health response implementation. PMID:21593260

  15. Immune efficacy of an adenoviral vector-based swine influenza vaccine against antigenically distinct H1N1 strains in mice.

    PubMed

    Wu, Yunpu; Yang, Dawei; Xu, Bangfeng; Liang, Wenhua; Sui, Jinyu; Chen, Yan; Yang, Huanliang; Chen, Hualan; Wei, Ping; Qiao, Chuanling

    2017-11-01

    Avian-like H1N1 swine influenza viruses are prevalent in pigs and have occasionally crossed the species barrier and infected humans, which highlights the importance of preventing swine influenza. Human adenovirus serotype 5 (Ad5) has been tested in human influenza vaccine clinical trials and has exhibited a reliable safety profile. Here, we generated a replication-defective, recombinant adenovirus (designated as rAd5-avH1HA) expressing the hemagglutinin gene of an avian-like H1N1 virus (A/swine/Zhejiang/199/2013, ZJ/199/13). Using a BALB/c mouse model, we showed that a two-dose intramuscular administration of recombinant rAd5-avH1HA induced high levels of hemagglutination inhibition antibodies and prevented homologous and heterologous H1N1 virus-induced weight loss, as well as viral replication in the nasal turbinates and lungs of mice. Furthermore, a prime-boost immunization strategy trial with a recombinant plasmid (designated as pCAGGS-HA) followed by rAd5-avH1HA vaccine provided effective protection against homologous and heterologous H1N1 virus infection in mice. These results indicate that rAd5-avH1HA is an efficacious genetically engineered vaccine candidate against H1N1 swine influenza. Future studies should examine its immune efficacy in pigs. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Fulminant fatal swine influenza (H1N1): Myocarditis, myocardial infarction, or severe influenza pneumonia?

    PubMed

    Cunha, Burke A; Syed, Uzma; Mickail, Nardeen

    2010-01-01

    The swine influenza (H1N1) pandemic began in Mexico and rapidly spread worldwide. As is the case with pandemic influenza A, the majority of early deaths have been in young healthy adults. The complications of pandemic H1N1 have been reported from several centers. Noteworthy has been the relative rarity of bacterial coinfection in bacterial pneumonia in hospitalized adults with H1N1 pneumonia. Simultaneous bacterial community-acquired pneumonia due to methicillin-sensitive Staphylococcus aureus or community-acquired methicillin resistant S. aureus and subsequent bacterial community-acquired pneumonia due to S. pneumoniae or Haemophilus influenzae have been reportedly rare (0.4%-4% of well-documented cases). Cardiac complications of H1N1 infection have been uncommon. Young healthy adults without a cardiac history who have H1N1 and chest pain usually have either acute myocardial infarction or acute myocarditis. Cardiac symptomatology with H1N1 often overshadows pulmonary manifestations, that is, influenza pneumonia. With H1N1 pneumonia, clinicians should be alert for otherwise unexplained tachycardia or chest pain that may represent acute myocardial infarction or myocarditis. We present a case of rapidly fatal H1N1 in a young adult treated with oseltamivir and peramivir. He was initially tachycardic, thought to represent myocarditis. He subsequently became hypotensive and expired. At autopsy there was cardiomegaly present but there were no signs of acute myocardial infarction or myocarditis. Pathologically, he died of severe H1N1 pneumonia and not bacterial pneumonia. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Safety and efficacy of a novel live attenuated influenza vaccine against pandemic H1N1 in swine

    USDA-ARS?s Scientific Manuscript database

    On June 11, 2009 the World Health Organization (WHO) declared that the outbreaks caused by novel swine-origin influenza A (H1N1) virus had reached pandemic proportions. The pandemic H1N1 (H1N1pdm) is the predominant influenza strain in the human population. It has also crossed the species barriers a...

  18. Infection dynamics of pandemic 2009 H1N1 influenza virus in a two-site swine herd.

    PubMed

    Allerson, M W; Davies, P R; Gramer, M R; Torremorell, M

    2014-12-01

    Influenza A viruses are common causes of respiratory disease in pigs and can be transmitted among multiple host species, including humans. The current lack of published information on infection dynamics of influenza viruses within swine herds hinders the ability to make informed animal health, biosecurity and surveillance programme decisions. The objectives of this serial cross-sectional study were to describe the infection dynamics of influenza virus in a two-site swine system by estimating the prevalence of influenza virus in animal subpopulations at the swine breeding herd and describing the temporal pattern of infection in a selected cohort of growing pigs weaned from the breeding herd. Nasal swab and blood samples were collected at approximately 30-day intervals from the swine breeding herd (Site 1) known to be infected with pandemic 2009 H1N1 influenza virus. Sows, gilts and neonatal pigs were sampled at each sampling event, and samples were tested for influenza virus genome using matrix gene RRT-PCR. Influenza virus was detected in neonatal pigs, but was not detected in sow or gilt populations via RRT-PCR. A virus genetically similar to that detected in the neonatal pig population at Site 1 was also detected at the wean-to-finish site (Site 2), presumably following transportation of infected weaned pigs. Longitudinal sampling of nasal swabs and oral fluids revealed that influenza virus persisted in the growing pigs at Site 2 for at least 69 days. The occurrence of influenza virus in neonatal pigs, but not breeding females, at Site 1 emphasizes the potential for virus maintenance in this dynamic subpopulation, the importance of including this subpopulation in surveillance programmes and the potential transport of influenza virus between sites via the movement of weaned pigs. © 2013 Blackwell Verlag GmbH.

  19. Antiviral Responses by Swine Primary Bronchoepithelial Cells Are Limited Compared to Human Bronchoepithelial Cells Following Influenza Virus Infection

    PubMed Central

    Hauser, Mary J.; Dlugolenski, Daniel; Culhane, Marie R.; Wentworth, David E.; Tompkins, S. Mark; Tripp, Ralph A.

    2013-01-01

    Swine generate reassortant influenza viruses because they can be simultaneously infected with avian and human influenza; however, the features that restrict influenza reassortment in swine and human hosts are not fully understood. Type I and III interferons (IFNs) act as the first line of defense against influenza virus infection of respiratory epithelium. To determine if human and swine have different capacities to mount an antiviral response the expression of IFN and IFN-stimulated genes (ISG) in normal human bronchial epithelial (NHBE) cells and normal swine bronchial epithelial (NSBE) cells was evaluated following infection with human (H3N2), swine (H1N1), and avian (H5N3, H5N2, H5N1) influenza A viruses. Expression of IFNλ and ISGs were substantially higher in NHBE cells compared to NSBE cells following H5 avian influenza virus infection compared to human or swine influenza virus infection. This effect was associated with reduced H5 avian influenza virus replication in human cells at late times post infection. Further, RIG-I expression was lower in NSBE cells compared to NHBE cells suggesting reduced virus sensing. Together, these studies identify key differences in the antiviral response between human and swine respiratory epithelium alluding to differences that may govern influenza reassortment. PMID:23875024

  20. Comparison of the usefulness of the CACO-2 cell line with standard substrates for isolation of swine influenza A viruses.

    PubMed

    Chiapponi, Chiara; Zanni, Irene; Garbarino, Chiara; Barigazzi, Giuseppe; Foni, Emanuela

    2010-01-01

    Influenza A virus isolation is undertaken routinely in embryonated chicken eggs, but to improve virus detection various cell lines can be used. The CACO-2 cell line was compared to the MDCK cell line and embryonated chicken eggs for the isolation of H1N1, H1N2, H3N2 swine influenza A virus subtypes from clinical specimens. From 2006 to 2008, 104 influenza A samples found positive by PCR from 42 respiratory outbreaks in Italian swine farms were examined by virus isolation. Sixty swine influenza A viruses were isolated (16 H1N1, 28 H1N2 and 16 H3N2) and their growth behaviour on the different substrates was examined. 16/16 H1N1, 28/28 H1N2 and 8/16 of H3N2 viruses were isolated from the CACO-2 cell line, while 7/16 H1N1, 3/28 H1N2 and 16/16 H3N2 viruses were isolated using embryonated chicken eggs. Only 9/16 H1N1, 1/28 H1N2 and 6/16 H3N2 viruses replicated in MDCK cells. A link was found between viral hemagglutinin and the isolation rate on the various substrates. The CACO-2 line was statistically more sensitive (Fisher's exact test, p<0.01) compared to the MDCK cells and embryonated chicken eggs for the isolation of H1N1 and H1N2 subtypes. In contrast influenza A H3N2 virus was isolated more readily in embryonated chicken eggs than in cultured cells (Fisher's exact test, p<0.01).

  1. Pre-infection of pigs with Mycoplasma hyopneumoniae modifies outcomes of infection with European swine influenza virus of H1N1, but not H1N2, subtype.

    PubMed

    Deblanc, C; Gorin, S; Quéguiner, S; Gautier-Bouchardon, A V; Ferré, S; Amenna, N; Cariolet, R; Simon, G

    2012-05-25

    Swine influenza virus (SIV) and Mycoplasma hyopneumoniae (Mhp) are widespread in farms and are major pathogens involved in the porcine respiratory disease complex (PRDC). The aim of this experiment was to compare the pathogenicity of European avian-like swine H1N1 and European human-like reassortant swine H1N2 viruses in naïve pigs and in pigs previously infected with Mhp. Six groups of SPF pigs were inoculated intra-tracheally with either Mhp, or H1N1, or H1N2 or Mhp+H1N1 or Mhp+H1N2, both pathogens being inoculated at 21 days intervals in these two last groups. A mock-infected group was included. Although both SIV strains induced clinical signs when singly inoculated, results indicated that the H1N2 SIV was more pathogenic than the H1N1 virus, with an earlier shedding and a greater spread in lungs. Initial infection with Mhp before SIV inoculation increased flu clinical signs and pathogenesis (hyperthermia, loss of appetite, pneumonia lesions) due to the H1N1 virus but did not modify significantly outcomes of H1N2 infection. Thus, Mhp and SIV H1N1 appeared to act synergistically, whereas Mhp and SIV H1N2 would compete, as H1N2 infection led to the elimination of Mhp in lung diaphragmatic lobes. In conclusion, SIV would be a risk factor for the severity of respiratory disorders when associated with Mhp, depending on the viral subtype involved. This experimental model of coinfection with Mhp and avian-like swine H1N1 is a relevant tool for studying the pathogenesis of SIV-associated PRDC and testing intervention strategies for the control of the disease. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. PA-X protein contributes to virulence of triple-reassortant H1N2 influenza virus by suppressing early immune responses in swine.

    PubMed

    Xu, Guanlong; Zhang, Xuxiao; Liu, Qinfang; Bing, Guoxia; Hu, Zhe; Sun, Honglei; Xiong, Xin; Jiang, Ming; He, Qiming; Wang, Yu; Pu, Juan; Guo, Xin; Yang, Hanchun; Liu, Jinhua; Sun, Yipeng

    2017-08-01

    Previous studies have identified a functional role of PA-X for influenza viruses in mice and avian species; however, its role in swine remains unknown. Toward this, we constructed PA-X deficient virus (Sw-FS) in the background of a Triple-reassortment (TR) H1N2 swine influenza virus (SIV) to assess the impact of PA-X in viral virulence in pigs. Expression of PA-X in TR H1N2 SIV enhanced viral replication and host protein synthesis shutoff, and inhibited the mRNA levels of type I IFNs and proinflammatory cytokines in porcine cells. A delay of proinflammatory responses was observed in lungs of pigs infected by wild type SIV (Sw-WT) compared to Sw-FS. Furthermore, Sw-WT virus replicated and transmitted more efficiently than Sw-FS in pigs. These results highlight the importance of PA-X in the moderation of virulence and immune responses of TR SIV in swine, which indicated that PA-X is a pro-virulence factor in TR SIV in pigs. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Pandemic Paradox: Early Life H2N2 Pandemic Influenza Infection Enhanced Susceptibility to Death during the 2009 H1N1 Pandemic.

    PubMed

    Gagnon, Alain; Acosta, Enrique; Hallman, Stacey; Bourbeau, Robert; Dillon, Lisa Y; Ouellette, Nadine; Earn, David J D; Herring, D Ann; Inwood, Kris; Madrenas, Joaquin; Miller, Matthew S

    2018-01-16

    Recent outbreaks of H5, H7, and H9 influenza A viruses in humans have served as a vivid reminder of the potentially devastating effects that a novel pandemic could exert on the modern world. Those who have survived infections with influenza viruses in the past have been protected from subsequent antigenically similar pandemics through adaptive immunity. For example, during the 2009 H1N1 "swine flu" pandemic, those exposed to H1N1 viruses that circulated between 1918 and the 1940s were at a decreased risk for mortality as a result of their previous immunity. It is also generally thought that past exposures to antigenically dissimilar strains of influenza virus may also be beneficial due to cross-reactive cellular immunity. However, cohorts born during prior heterosubtypic pandemics have previously experienced elevated risk of death relative to surrounding cohorts of the same population. Indeed, individuals born during the 1890 H3Nx pandemic experienced the highest levels of excess mortality during the 1918 "Spanish flu." Applying Serfling models to monthly mortality and influenza circulation data between October 1997 and July 2014 in the United States and Mexico, we show corresponding peaks in excess mortality during the 2009 H1N1 "swine flu" pandemic and during the resurgent 2013-2014 H1N1 outbreak for those born at the time of the 1957 H2N2 "Asian flu" pandemic. We suggest that the phenomenon observed in 1918 is not unique and points to exposure to pandemic influenza early in life as a risk factor for mortality during subsequent heterosubtypic pandemics. IMPORTANCE The relatively low mortality experienced by older individuals during the 2009 H1N1 influenza virus pandemic has been well documented. However, reported situations in which previous influenza virus exposures have enhanced susceptibility are rare and poorly understood. One such instance occurred in 1918-when those born during the heterosubtypic 1890 H3Nx influenza virus pandemic experienced the highest

  4. Guinea pig model for evaluating the potential public health risk of swine and avian influenza viruses.

    PubMed

    Sun, Yipeng; Bi, Yuhai; Pu, Juan; Hu, Yanxin; Wang, Jingjing; Gao, Huijie; Liu, Linqing; Xu, Qi; Tan, Yuanyuan; Liu, Mengda; Guo, Xin; Yang, Hanchun; Liu, Jinhua

    2010-11-23

    The influenza viruses circulating in animals sporadically transmit to humans and pose pandemic threats. Animal models to evaluate the potential public health risk potential of these viruses are needed. We investigated the guinea pig as a mammalian model for the study of the replication and transmission characteristics of selected swine H1N1, H1N2, H3N2 and avian H9N2 influenza viruses, compared to those of pandemic (H1N1) 2009 and seasonal human H1N1, H3N2 influenza viruses. The swine and avian influenza viruses investigated were restricted to the respiratory system of guinea pigs and shed at high titers in nasal tracts without prior adaptation, similar to human strains. None of the swine and avian influenza viruses showed transmissibility among guinea pigs; in contrast, pandemic (H1N1) 2009 virus transmitted from infected guinea pigs to all animals and seasonal human influenza viruses could also horizontally transmit in guinea pigs. The analysis of the receptor distribution in the guinea pig respiratory tissues by lectin histochemistry indicated that both SAα2,3-Gal and SAα2,6-Gal receptors widely presented in the nasal tract and the trachea, while SAα2,3-Gal receptor was the main receptor in the lung. We propose that the guinea pig could serve as a useful mammalian model to evaluate the potential public health threat of swine and avian influenza viruses.

  5. Efficacy of a high-growth reassortant H1N1 influenza virus vaccine against the classical swine H1N1 subtype influenza virus in mice and pigs.

    PubMed

    Wen, Feng; Yu, Hai; Yang, Fu-Ru; Huang, Meng; Yang, Sheng; Zhou, Yan-Jun; Li, Ze-Jun; Tong, Guang-Zhi

    2014-11-01

    Swine influenza (SI) is an acute, highly contagious respiratory disease caused by swine influenza A viruses (SwIVs), and it poses a potential global threat to human health. Classical H1N1 (cH1N1) SwIVs are still circulating and remain the predominant subtype in the swine population in China. In this study, a high-growth reassortant virus (GD/PR8) harboring the hemagglutinin (HA) and neuraminidase (NA) genes from a novel cH1N1 isolate in China, A/Swine/Guangdong/1/2011 (GD/11) and six internal genes from the high-growth A/Puerto Rico/8/34(PR8) virus was generated by plasmid-based reverse genetics and tested as a candidate seed virus for the preparation of an inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice and pigs challenged with GD/11 virus. Prime and boost inoculation of GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting (HI) antibodies and IgG antibodies for GD/11 in both mice and pigs. Complete protection of mice and pigs against cH1N1 SIV challenge was observed, with significantly fewer lung lesions and reduced viral shedding in vaccine-inoculated animals compared with unvaccinated control animals. Our data demonstrated that the GD/PR8 may serve as the seed virus for a promising SwIVs vaccine to protect the swine population.

  6. Replication of swine and human influenza viruses in juvenile and layer turkey hens.

    PubMed

    Ali, Ahmed; Yassine, Hadi; Awe, Olusegun O; Ibrahim, Mahmoud; Saif, Yehia M; Lee, Chang-Won

    2013-04-12

    Since the first reported isolation of swine influenza viruses (SIVs) in turkeys in the 1980s, transmission of SIVs to turkeys was frequently documented. Recently, the 2009 pandemic H1N1 virus, that was thought to be of swine origin, was detected in turkeys with a severe drop in egg production. In this study, we assessed the infectivity of different mammalian influenza viruses including swine, pandemic H1N1 and seasonal human influenza viruses in both juvenile and layer turkeys. In addition, we investigated the potential influenza virus dissemination in the semen of experimentally infected turkey toms. Results showed that all mammalian origin influenza viruses tested can infect turkeys. SIVs were detected in respiratory and digestive tracts of both juvenile and layer turkeys. Variations in replication efficiencies among SIVs were observed especially in the reproductive tract of layer turkeys. Compared to SIVs, limited replication of seasonal human H1N1 and no detectable replication of recent human-like swine H1N2, pandemic H1N1 and seasonal human H3N2 viruses was noticed. All birds seroconverted to all tested viruses regardless of their replication level. In turkey toms, we were able to detect swine H3N2 virus in semen and reproductive tract of infected toms by real-time RT-PCR although virus isolation was not successful. These data suggest that turkey hens could be affected by diverse influenza strains especially SIVs. Moreover, the differences in the replication efficiency we demonstrated among SIVs and between SIV and human influenza viruses in layer turkeys suggest a possible use of turkeys as an animal model to study host tropism and pathogenesis of influenza viruses. Our results also indicate a potential risk of venereal transmission of influenza viruses in turkeys. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Introductions and Evolution of Human-Origin Seasonal Influenza A Viruses in Multinational Swine Populations

    PubMed Central

    Wentworth, David E.; Culhane, Marie R.; Vincent, Amy L.; Viboud, Cecile; LaPointe, Matthew P.; Lin, Xudong; Holmes, Edward C.; Detmer, Susan E.

    2014-01-01

    ABSTRACT The capacity of influenza A viruses to cross species barriers presents a continual threat to human and animal health. Knowledge of the human-swine interface is particularly important for understanding how viruses with pandemic potential evolve in swine hosts. We sequenced the genomes of 141 influenza viruses collected from North American swine during 2002 to 2011 and identified a swine virus that possessed all eight genome segments of human seasonal A/H3N2 virus origin. A molecular clock analysis indicates that this virus—A/sw/Saskatchewan/02903/2009(H3N2)—has likely circulated undetected in swine for at least 7 years. For historical context, we performed a comprehensive phylogenetic analysis of an additional 1,404 whole-genome sequences from swine influenza A viruses collected globally during 1931 to 2013. Human-to-swine transmission occurred frequently over this time period, with 20 discrete introductions of human seasonal influenza A viruses showing sustained onward transmission in swine for at least 1 year since 1965. Notably, human-origin hemagglutinin (H1 and H3) and neuraminidase (particularly N2) segments were detected in swine at a much higher rate than the six internal gene segments, suggesting an association between the acquisition of swine-origin internal genes via reassortment and the adaptation of human influenza viruses to new swine hosts. Further understanding of the fitness constraints on the adaptation of human viruses to swine, and vice versa, at a genomic level is central to understanding the complex multihost ecology of influenza and the disease threats that swine and humans pose to each other. IMPORTANCE The swine origin of the 2009 A/H1N1 pandemic virus underscored the importance of understanding how influenza A virus evolves in these animals hosts. While the importance of reassortment in generating genetically diverse influenza viruses in swine is well documented, the role of human-to-swine transmission has not been as

  8. Serological evidence of pig-to-human influenza virus transmission on Thai swine farms.

    PubMed

    Kitikoon, Pravina; Sreta, Donruethai; Tuanudom, Ranida; Amonsin, Alongkorn; Suradhat, Sanipa; Oraveerakul, Kanisak; Poovorawan, Yong; Thanawongnuwech, Roongroje

    2011-03-24

    We investigated influenza interspecies transmission in two commercial swine farms in Thailand. Sera from swine-exposed workers (n=78), age-matched non-swine-exposed healthy people (n=60) and swine populations in both farms (n=85) were studied. Hemagglutination-inhibition (HI) assay was performed on Thai swine H1 viruses (swH1N1 and swH1N2) isolated from both farms. Thai human H1N1 (huH1N1) and pandemic H1N1 2009 (pH1N1) were also used as test antigens. The hemagglutinin (HA) 1 genes of swH1N1 and swH1N2 viruses were sequenced and shown to be genetically distinct from the Thai huH1N1 and pH1N1 viruses. Evidence of pig-to-human influenza virus transmission was found in farm workers with increased odds of elevated antibody titers to both swH1N1 (OR 42.63, 95% CI, 14.65-124) and swH1N2 (OR 58, 95% CI, 13.12-256.3) viruses. No evidence of human-to-pig influenza virus transmission was detected in this study. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Spatial Dynamics of Human-Origin H1 Influenza A Virus in North American Swine

    PubMed Central

    Nelson, Martha I.; Lemey, Philippe; Tan, Yi; Vincent, Amy; Lam, Tommy Tsan-Yuk; Detmer, Susan; Viboud, Cécile; Suchard, Marc A.; Rambaut, Andrew; Holmes, Edward C.; Gramer, Marie

    2011-01-01

    The emergence and rapid global spread of the swine-origin H1N1/09 pandemic influenza A virus in humans underscores the importance of swine populations as reservoirs for genetically diverse influenza viruses with the potential to infect humans. However, despite their significance for animal and human health, relatively little is known about the phylogeography of swine influenza viruses in the United States. This study utilizes an expansive data set of hemagglutinin (HA1) sequences (n = 1516) from swine influenza viruses collected in North America during the period 2003–2010. With these data we investigate the spatial dissemination of a novel influenza virus of the H1 subtype that was introduced into the North American swine population via two separate human-to-swine transmission events around 2003. Bayesian phylogeographic analysis reveals that the spatial dissemination of this influenza virus in the US swine population follows long-distance swine movements from the Southern US to the Midwest, a corn-rich commercial center that imports millions of swine annually. Hence, multiple genetically diverse influenza viruses are introduced and co-circulate in the Midwest, providing the opportunity for genomic reassortment. Overall, the Midwest serves primarily as an ecological sink for swine influenza in the US, with sources of virus genetic diversity instead located in the Southeast (mainly North Carolina) and South-central (mainly Oklahoma) regions. Understanding the importance of long-distance pig transportation in the evolution and spatial dissemination of the influenza virus in swine may inform future strategies for the surveillance and control of influenza, and perhaps other swine pathogens. PMID:21695237

  10. Influenza A Viruses Detected in Swine in Southern Germany after the H1N1 Pandemic in 2009.

    PubMed

    Pippig, J; Ritzmann, M; Büttner, M; Neubauer-Juric, A

    2016-11-01

    Infections with influenza A viruses (IAV) are highly prevalent in swine populations, and stable cocirculation of at least three lineages has been well documented in European swine - till 2009. However, since the emergence of the human pandemic pdmH1N1 virus in 2009, which has been (re)introduced into individual swine herds worldwide, the situation has been changing. These variations in the respective IAV pools within pig populations are of major interest, and the zoonotic potential of putative emerging viruses needs to be evaluated. As data on recent IAV in swine from southern Germany were relatively sparse, the purpose of this study was to determine the major IAV subtypes actually present in this region. To this aim, from 2010 to 2013, 1417 nasal swabs or lung tissue samples from pigs with respiratory disease were screened for IAV genomes. Overall, in 130 holdings IAV genomes were detected by real-time RT-PCR targeting the matrix protein gene. For further analyses, several PCR protocols were adapted to quickly subtype between H1, pdmH1, H3, N1 and N2 sequences. Taken together, cocirculation of the three stable European lineages of IAV was confirmed for Bavaria. H1N1 sequences were identified in 59, whereas H1N2 genomes were only diagnosed in 14, and H3N2 in 9 of the holdings analysed. However, pdmH1 in combination with N1 was detected in 2010, 2012 and 2013 confirming a presence, albeit in low prevalence, likewise pdmH1N2 reassortant viruses. Interestingly, individual cases of coinfections with more than one subtype were diagnosed. Partial genome sequences were determined and phylogenetic analyses performed. Clearly other than in the human population classically circulating IAV have not been displaced by pdmH1N1 in Bavarian swine. However, some interesting viruses were detected. Further surveillance of these viruses in the Bavarian pig population will be of major importance, to monitor future developments. © 2016 Blackwell Verlag GmbH.

  11. Comparative study of the hemagglutinin and neuraminidase genes of influenza A virus H3N2, H9N2, and H5N1 subtypes using bioinformatics techniques.

    PubMed

    Ahn, Insung; Son, Hyeon S

    2007-07-01

    To investigate the genomic patterns of influenza A virus subtypes, such as H3N2, H9N2, and H5N1, we collected 1842 sequences of the hemagglutinin and neuraminidase genes from the NCBI database and parsed them into 7 categories: accession number, host species, sampling year, country, subtype, gene name, and sequence. The sequences that were isolated from the human, avian, and swine populations were extracted and stored in a MySQL database for intensive analysis. The GC content and relative synonymous codon usage (RSCU) values were calculated using JAVA codes. As a result, correspondence analysis of the RSCU values yielded the unique codon usage pattern (CUP) of each subtype and revealed no extreme differences among the human, avian, and swine isolates. H5N1 subtype viruses exhibited little variation in CUPs compared with other subtypes, suggesting that the H5N1 CUP has not yet undergone significant changes within each host species. Moreover, some observations may be relevant to CUP variation that has occurred over time among the H3N2 subtype viruses isolated from humans. All the sequences were divided into 3 groups over time, and each group seemed to have preferred synonymous codon patterns for each amino acid, especially for arginine, glycine, leucine, and valine. The bioinformatics technique we introduce in this study may be useful in predicting the evolutionary patterns of pandemic viruses.

  12. Two different genotypes of H1N2 swine influenza virus isolated in northern China and their pathogenicity in animals.

    PubMed

    Yang, Huanliang; Chen, Yan; Qiao, Chuanling; Xu, Chuantian; Yan, Minghua; Xin, Xiaoguang; Bu, Zhigao; Chen, Hualan

    2015-02-25

    During 2006 and 2007, two swine-origin triple-reassortant influenza A (H1N2) viruses were isolated from pigs in northern China, and the antigenic characteristics of the hemagglutinin protein of the viruses were examined. Genotyping and phylogenetic analyses demonstrated different emergence patterns for the two H1N2 viruses, Sw/Hebei/10/06 and Sw/Tianjin/1/07. Sequences for the other genes encoding the internal proteins were compared with the existing data to determine their origins and establish the likely mechanisms of genetic reassortment. Sw/Hebei/10/06 is an Sw/Indiana/9K035/99-like virus, whereas Sw/Tianjin/1/07 represents a new H1N2 genotype with surface genes of classic swine and human origin and internal genes originating from the Eurasian avian-like swine H1N1 virus. Six-week-old female BALB/c mice infected with the Sw/HeB/10/06 and Sw/TJ/1/07 viruses showed an average weight loss of 12.8% and 8.1%, respectively. Healthy six-week-old pigs were inoculated intranasally with either the Sw/HeB/10/06 or Sw/TJ/1/07 virus. No considerable changes in the clinical presentation were observed post-inoculation in any of the virus-inoculated groups, and the viruses effectively replicated in the nasal cavity and lung tissue. Based on the results, it is possible that the new genotype of the swine H1N2 virus that emerged in China may become widespread in the swine population and pose a potential threat to public health. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Protective efficacy of a high-growth reassortant swine H3N2 inactivated vaccine constructed by reverse genetic manipulation

    PubMed Central

    Wen, Feng; Ma, Ji-Hong; Yang, Fu-Ru; Huang, Meng; Zhou, Yan-Jun; Li, Ze-Jun

    2014-01-01

    Novel reassortant H3N2 swine influenza viruses (SwIV) with the matrix gene from the 2009 H1N1 pandemic virus have been isolated in many countries as well as during outbreaks in multiple states in the United States, indicating that H3N2 SwIV might be a potential threat to public health. Since southern China is the world's largest producer of pigs, efficient vaccines should be developed to prevent pigs from acquiring H3N2 subtype SwIV infections, and thus limit the possibility of SwIV infection at agricultural fairs. In this study, a high-growth reassortant virus (GD/PR8) was generated by plasmid-based reverse genetics and tested as a candidate inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice by challenging them with another H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05 (H3N2) (HLJ/05)]. Prime and booster inoculation with GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting antibodies and IgG antibodies. Complete protection of mice against H3N2 SwIV was observed, with significantly reduced lung lesion and viral loads in vaccine-inoculated mice relative to mock-vaccinated controls. These results suggest that the GD/PR8 vaccine may serve as a promising candidate for rapid intervention of H3N2 SwIV outbreaks in China. PMID:24675833

  14. Guinea Pig Model for Evaluating the Potential Public Health Risk of Swine and Avian Influenza Viruses

    PubMed Central

    Pu, Juan; Hu, Yanxin; Wang, Jingjing; Gao, Huijie; Liu, Linqing; Xu, Qi; Tan, Yuanyuan; Liu, Mengda; Guo, Xin; Yang, Hanchun; Liu, Jinhua

    2010-01-01

    Background The influenza viruses circulating in animals sporadically transmit to humans and pose pandemic threats. Animal models to evaluate the potential public health risk potential of these viruses are needed. Methodology/Principal Findings We investigated the guinea pig as a mammalian model for the study of the replication and transmission characteristics of selected swine H1N1, H1N2, H3N2 and avian H9N2 influenza viruses, compared to those of pandemic (H1N1) 2009 and seasonal human H1N1, H3N2 influenza viruses. The swine and avian influenza viruses investigated were restricted to the respiratory system of guinea pigs and shed at high titers in nasal tracts without prior adaptation, similar to human strains. None of the swine and avian influenza viruses showed transmissibility among guinea pigs; in contrast, pandemic (H1N1) 2009 virus transmitted from infected guinea pigs to all animals and seasonal human influenza viruses could also horizontally transmit in guinea pigs. The analysis of the receptor distribution in the guinea pig respiratory tissues by lectin histochemistry indicated that both SAα2,3-Gal and SAα2,6-Gal receptors widely presented in the nasal tract and the trachea, while SAα2,3-Gal receptor was the main receptor in the lung. Conclusions/Significance We propose that the guinea pig could serve as a useful mammalian model to evaluate the potential public health threat of swine and avian influenza viruses. PMID:21124850

  15. Antigenically Diverse Swine Origin H1N1 Variant Influenza Viruses Exhibit Differential Ferret Pathogenesis and Transmission Phenotypes.

    PubMed

    Pulit-Penaloza, Joanna A; Jones, Joyce; Sun, Xiangjie; Jang, Yunho; Thor, Sharmi; Belser, Jessica A; Zanders, Natosha; Creager, Hannah M; Ridenour, Callie; Wang, Li; Stark, Thomas J; Garten, Rebecca; Chen, Li-Mei; Barnes, John; Tumpey, Terrence M; Wentworth, David E; Maines, Taronna R; Davis, C Todd

    2018-06-01

    Influenza A(H1) viruses circulating in swine represent an emerging virus threat, as zoonotic infections occur sporadically following exposure to swine. A fatal infection caused by an H1N1 variant (H1N1v) virus was detected in a patient with reported exposure to swine and who presented with pneumonia, respiratory failure, and cardiac arrest. To understand the genetic and phenotypic characteristics of the virus, genome sequence analysis, antigenic characterization, and ferret pathogenesis and transmissibility experiments were performed. Antigenic analysis of the virus isolated from the fatal case, A/Ohio/09/2015, demonstrated significant antigenic drift away from the classical swine H1N1 variant viruses and H1N1 pandemic 2009 viruses. A substitution in the H1 hemagglutinin (G155E) was identified that likely impacted antigenicity, and reverse genetics was employed to understand the molecular mechanism of antibody escape. Reversion of the substitution to 155G, in a reverse genetics A/Ohio/09/2015 virus, showed that this residue was central to the loss of hemagglutination inhibition by ferret antisera raised against a prototypical H1N1 pandemic 2009 virus (A/California/07/2009), as well as gamma lineage classical swine H1N1 viruses, demonstrating the importance of this residue for antibody recognition of this H1 lineage. When analyzed in the ferret model, A/Ohio/09/2015 and another H1N1v virus, A/Iowa/39/2015, as well as A/California/07/2009, replicated efficiently in the respiratory tract of ferrets. The two H1N1v viruses transmitted efficiently among cohoused ferrets, but respiratory droplet transmission studies showed that A/California/07/2009 transmitted through the air more efficiently. Preexisting immunity to A/California/07/2009 did not fully protect ferrets from challenge with A/Ohio/09/2015. IMPORTANCE Human infections with classical swine influenza A(H1N1) viruses that circulate in pigs continue to occur in the United States following exposure to swine. To

  16. Replication and Immunogenicity of Swine, Equine, and Avian H3 Subtype Influenza Viruses in Mice and Ferrets

    PubMed Central

    Baz, Mariana; Paskel, Myeisha; Matsuoka, Yumiko; Zengel, James; Cheng, Xing; Jin, Hong

    2013-01-01

    Since it is difficult to predict which influenza virus subtype will cause an influenza pandemic, it is important to prepare influenza virus vaccines against different subtypes and evaluate the safety and immunogenicity of candidate vaccines in preclinical and clinical studies prior to a pandemic. In addition to infecting humans, H3 influenza viruses commonly infect pigs, horses, and avian species. We selected 11 swine, equine, and avian H3 influenza viruses and evaluated their kinetics of replication and ability to induce a broadly cross-reactive antibody response in mice and ferrets. The swine and equine viruses replicated well in the upper respiratory tract of mice. With the exception of one avian virus that replicated poorly in the lower respiratory tract, all of the viruses replicated in mouse lungs. In ferrets, all of the viruses replicated well in the upper respiratory tract, but the equine viruses replicated poorly in the lungs. Extrapulmonary spread was not observed in either mice or ferrets. No single virus elicited antibodies that cross-reacted with viruses from all three animal sources. Avian and equine H3 viruses elicited broadly cross-reactive antibodies against heterologous viruses isolated from the same or other species, but the swine viruses did not. We selected an equine and an avian H3 influenza virus for further development as vaccines. PMID:23576512

  17. Full genomic analysis of an influenza A (H1N2) virus identified during 2009 pandemic in Eastern India: evidence of reassortment event between co-circulating A(H1N1)pdm09 and A/Brisbane/10/2007-like H3N2 strains.

    PubMed

    Mukherjee, Tapasi Roy; Agrawal, Anurodh S; Chakrabarti, Sekhar; Chawla-Sarkar, Mamta

    2012-10-11

    During the pandemic [Influenza A(H1N1)pdm09] period in 2009-2010, an influenza A (Inf-A) virus with H1N2 subtype (designated as A/Eastern India/N-1289/2009) was detected from a 25 years old male from Mizoram (North-eastern India). To characterize full genome of the H1N2 influenza virus. For initial detection of Influenza viruses, amplification of matrix protein (M) gene of Inf-A and B viruses was carried out by real time RT-PCR. Influenza A positive viruses are then further subtyped with HA and NA gene specific primers. Sequencing and the phylogenetic analysis was performed for the H1N2 strain to understand its origin. The outcome of this full genome study revealed a unique reassortment event where the N-1289 virus acquired it's HA gene from a 2009 pandemic H1N1 virus with swine origin and the other genes from H3N2-like viruses of human origin. This study provides information on possibility of occurrence of reassortment events during influenza season when infectivity is high and two different subtypes of Inf-A viruses co-circulate in same geographical location.

  18. A bivalent live-attenuated influenza vaccine for the control and prevention of H3N8 and H3N2 canine influenza viruses.

    PubMed

    Rodriguez, Laura; Nogales, Aitor; Murcia, Pablo R; Parrish, Colin R; Martínez-Sobrido, Luis

    2017-08-03

    Canine influenza viruses (CIVs) cause a contagious respiratory disease in dogs. CIV subtypes include H3N8, which originated from the transfer of H3N8 equine influenza virus (EIV) to dogs; and the H3N2, which is an avian-origin virus adapted to infect dogs. Only inactivated influenza vaccines (IIVs) are currently available against the different CIV subtypes. However, the efficacy of these CIV IIVs is not optimal and improved vaccines are necessary for the efficient prevention of disease caused by CIVs in dogs. Since live-attenuated influenza vaccines (LAIVs) induce better immunogenicity and protection efficacy than IIVs, we have combined our previously described H3N8 and H3N2 CIV LAIVs to create a bivalent vaccine against both CIV subtypes. Our findings show that, in a mouse model of infection, the bivalent CIV LAIV is safe and able to induce, upon a single intranasal immunization, better protection than that induced by a bivalent CIV IIV against subsequent challenge with H3N8 or H3N2 CIVs. These protection results also correlated with the ability of the bivalent CIV LAIV to induce better humoral immune responses. This is the first description of a bivalent LAIV for the control and prevention of H3N8 and H3N2 CIV infections in dogs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Development of DIVA (differentiation of infected from vaccinated animals) vaccines utilizing heterologous NA and NS1 protein strategies for the control of triple reassortant H3N2 influenza in turkeys

    USDA-ARS?s Scientific Manuscript database

    Since 2003, triple reassortant (TR) swine H3N2 influenza viruses containing gene segments from human, avian and swine origins have been detected in the U.S. turkey populations. The initial outbreak that occurred even involved birds that were vaccinated with the currently available H3 swine- and avia...

  20. Efficacy of influenza vaccination and tamiflu® treatment--comparative studies with Eurasian Swine influenza viruses in pigs.

    PubMed

    Duerrwald, Ralf; Schlegel, Michael; Bauer, Katja; Vissiennon, Théophile; Wutzler, Peter; Schmidtke, Michaela

    2013-01-01

    Recent epidemiological developments demonstrated that gene segments of swine influenza A viruses can account for antigenic changes as well as reduced drug susceptibility of pandemic influenza A viruses. This raises questions about the efficacy of preventive measures against swine influenza A viruses. Here, the protective effect of vaccination was compared with that of prophylactic Tamiflu® treatment against two Eurasian swine influenza A viruses. 11-week-old pigs were infected by aerosol nebulisation with high doses of influenza virus A/swine/Potsdam/15/1981 (H1N1/1981, heterologous challenge to H1N1 vaccine strain) and A/swine/Bakum/1832/2000 (H1N2/2000, homologous challenge to H1N2 vaccine strain) in two independent trials. In each trial (i) 10 pigs were vaccinated twice with a trivalent vaccine (RESPIPORC® FLU3; 28 and 7 days before infection), (ii) another 10 pigs received 150 mg/day of Tamiflu® for 5 days starting 12 h before infection, and (iii) 12 virus-infected pigs were left unvaccinated and untreated and served as controls. Both viruses replicated efficiently in porcine respiratory organs causing influenza with fever, dyspnoea, and pneumonia. Tamiflu® treatment as well as vaccination prevented clinical signs and significantly reduced virus shedding. Whereas after homologous challenge with H1N2/2000 no infectious virus in lung and hardly any lung inflammation were detected, the virus titre was not and the lung pathology was only partially reduced in H1N1/1981, heterologous challenged pigs. Tamiflu® application did not affect these study parameters. In conclusion, all tested preventive measures provided protection against disease. Vaccination additionally prevented virus replication and histopathological changes in the lung of homologous challenged pigs.

  1. Genomic reassortants of pandemic A (H1N1) 2009 virus and endemic porcine H1 and H3 viruses in swine in Japan.

    PubMed

    Kirisawa, Rikio; Ogasawara, Yoshitaka; Yoshitake, Hayato; Koda, Asuka; Furuya, Tokujiro

    2014-11-01

    From 2010 to 2013 in Japan, we isolated 11 swine influenza viruses (SIVs) from pigs showing respiratory symptoms. Sequence and phylogenetic analyses showed that 6 H1N1 viruses originated from the pandemic (H1N1) 2009 (pdm 09) virus and the other 5 viruses were reassortants between SIVs and pdm 09 viruses, representing 4 genotypes. Two H1N2 viruses contained H1 and N2 genes originated from Japanese H1N2 SIV together with internal genes of pdm 09 viruses. Additionally, 1 H1N2 virus contained a further NP gene originating from Japanese H1N2 SIV. One H1N1 virus contained only the H1 gene originating from Japanese H1 SIV in a pdm 09 virus background. One H3N2 virus contained H3 and N2 genes originating from Japanese H3N2 SIV together with internal genes of pdm 09 virus. The results indicate that pdm 09 viruses are distributed widely in the Japanese swine population and that several reassortments with Japanese SIVs have occurred.

  2. Outbreaks of pandemic (H1N1) 2009 and seasonal influenza A (H3N2) on cruise ship.

    PubMed

    Ward, Kate A; Armstrong, Paul; McAnulty, Jeremy M; Iwasenko, Jenna M; Dwyer, Dominic E

    2010-11-01

    To determine the extent and pattern of influenza transmission and effectiveness of containment measures, we investigated dual outbreaks of pandemic (H1N1) 2009 and influenza A (H3N2) that had occurred on a cruise ship in May 2009. Of 1,970 passengers and 734 crew members, 82 (3.0%) were infected with pandemic (H1N1) 2009 virus, 98 (3.6%) with influenza A (H3N2) virus, and 2 (0.1%) with both. Among 45 children who visited the ship's childcare center, infection rate for pandemic (H1N1) 2009 was higher than that for influenza A (H3N2) viruses. Disembarked passengers reported a high level of compliance with isolation and quarantine recommendations. We found 4 subsequent cases epidemiologically linked to passengers but no evidence of sustained transmission to the community or passengers on the next cruise. Among this population of generally healthy passengers, children seemed more susceptible to pandemic (H1N1) 2009 than to influenza (H3N2) viruses. Intensive disease control measures successfully contained these outbreaks.

  3. Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States.

    PubMed

    Rajao, Daniela S; Anderson, Tavis K; Kitikoon, Pravina; Stratton, Jered; Lewis, Nicola S; Vincent, Amy L

    2018-05-01

    Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission. Published by Elsevier Inc.

  4. Limited susceptibility and lack of systemic infection by an H3N2 swine influenza virus in intranasally inoculated chickens.

    PubMed

    Thomas, Colleen; Manin, Timofey B; Andriyasov, Artem V; Swayne, David E

    2008-09-01

    Chickens were intranasally inoculated with the swine influenza virus (SIV) A/swine/NC/307408/04 (H3N2) (NC/04 SIV) to determine the infectivity of a North American SIV for chickens, as well as the possibility of chicken meat serving as a transmission vehicle for SIV. White leghorn (WL) layer-type chickens were used for initial pathotyping and infectivity tests, and a more comprehensive intranasal pathogenesis study was done with white Plymouth rock (WPR) broiler-type chickens. None of the NC/04 SIV-inoculated WL or WPR chickens displayed clinical signs. Serologic tests showed that the virus was able to infect both intranasally inoculated WL and WPR chickens, but the antibody titers were low, suggesting inefficient replication. Some of the NC/04 SIV-inoculated WL chickens shed low levels of virus, mostly from the alimentary tract, but viral shedding was not detected in NC/04 SIV-inoculated WPR chickens. The comprehensive pathogenesis study demonstrated that the virus did not cause systemic infections in WPR chickens, and feeding breast and thigh meat from the NC/04 SIV-inoculated WPR to WL chickens did not transmit NC/04 SIV.

  5. Natural co-infection of influenza A/H3N2 and A/H1N1pdm09 viruses resulting in a reassortant A/H3N2 virus.

    PubMed

    Rith, Sareth; Chin, Savuth; Sar, Borann; Y, Phalla; Horm, Srey Viseth; Ly, Sovann; Buchy, Philippe; Dussart, Philippe; Horwood, Paul F

    2015-12-01

    Despite annual co-circulation of different subtypes of seasonal influenza, co-infections between different viruses are rarely detected. These co-infections can result in the emergence of reassortant progeny. We document the detection of an influenza co-infection, between influenza A/H3N2 with A/H1N1pdm09 viruses, which occurred in a 3 year old male in Cambodia during April 2014. Both viruses were detected in the patient at relatively high viral loads (as determined by real-time RT-PCR CT values), which is unusual for influenza co-infections. As reassortment can occur between co-infected influenza A strains we isolated plaque purified clonal viral populations from the clinical material of the patient infected with A/H3N2 and A/H1N1pdm09. Complete genome sequences were completed for 7 clonal viruses to determine if any reassorted viruses were generated during the influenza virus co-infection. Although most of the viral sequences were consistent with wild-type A/H3N2 or A/H1N1pdm09, one reassortant A/H3N2 virus was isolated which contained an A/H1N1pdm09 NS1 gene fragment. The reassortant virus was viable and able to infect cells, as judged by successful passage in MDCK cells, achieving a TCID50 of 10(4)/ml at passage number two. There is no evidence that the reassortant virus was transmitted further. The co-infection occurred during a period when co-circulation of A/H3N2 and A/H1N1pdm09 was detected in Cambodia. It is unclear how often influenza co-infections occur, but laboratories should consider influenza co-infections during routine surveillance activities. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Canine susceptibility to human influenza viruses (A/pdm 09H1N1, A/H3N2 and B).

    PubMed

    Song, Daesub; Kim, Hyekwon; Na, Woonsung; Hong, Minki; Park, Seong-Jun; Moon, Hyoungjoon; Kang, Bokyu; Lyoo, Kwang-Soo; Yeom, Minjoo; Jeong, Dae Gwin; An, Dong-Jun; Kim, Jeong-Ki

    2015-02-01

    We investigated the infectivity and transmissibility of the human seasonal H3N2, pandemic (pdm) H1N1 (2009) and B influenza viruses in dogs. Dogs inoculated with human seasonal H3N2 and pdm H1N1 influenza viruses exhibited nasal shedding and were seroconverted against the viruses; this did not occur in the influenza B virus-inoculated dogs. Transmission of human H3N2 virus between dogs was demonstrated by observing nasal shedding and seroconversion in naïve dogs after contact with inoculated dogs. The seroprevalence study offered evidence of human H3N2 infection occurring in dogs since 2008. Furthermore, serological evidence of pdm H1N1 influenza virus infection alone and in combination with canine H3N2 virus was found in the serum samples collected from field dogs during 2010 and 2011. Our results suggest that dogs may be hosts for human seasonal H3N2 and pdm H1N1 influenza viruses. © 2015 The Authors.

  7. Evolutionary Dynamics of Influenza A Viruses in US Exhibition Swine

    PubMed Central

    Nelson, Martha I.; Wentworth, David E.; Das, Suman R.; Sreevatsan, Srinand; Killian, Mary L.; Nolting, Jacqueline M.; Slemons, Richard D.; Bowman, Andrew S.

    2016-01-01

    The role of exhibition swine in influenza A virus transmission was recently demonstrated by >300 infections with influenza A(H3N2) variant viruses among individuals who attended agricultural fairs. Through active influenza A virus surveillance in US exhibition swine and whole-genome sequencing of 380 isolates, we demonstrate that exhibition swine are actively involved in the evolution of influenza A viruses, including zoonotic strains. First, frequent introduction of influenza A viruses from commercial swine populations provides new genetic diversity in exhibition pigs each year locally. Second, genomic reassortment between viruses cocirculating in exhibition swine increases viral diversity. Third, viral migration between exhibition swine in neighboring states demonstrates that movements of exhibition pigs contributes to the spread of genetic diversity. The unexpected frequency of viral exchange between commercial and exhibition swine raises questions about the understudied interface between these populations. Overall, the complexity of viral evolution in exhibition swine indicates that novel viruses are likely to continually reemerge, presenting threats to humans. PMID:26243317

  8. Outbreaks of Pandemic (H1N1) 2009 and Seasonal Influenza A (H3N2) on Cruise Ship

    PubMed Central

    Ward, Kate A.; Armstrong, Paul; Iwasenko, Jenna M.; Dwyer, Dominic E.

    2010-01-01

    To determine the extent and pattern of influenza transmission and effectiveness of containment measures, we investigated dual outbreaks of pandemic (H1N1) 2009 and influenza A (H3N2) that had occurred on a cruise ship in May 2009. Of 1,970 passengers and 734 crew members, 82 (3.0%) were infected with pandemic (H1N1) 2009 virus, 98 (3.6%) with influenza A (H3N2) virus, and 2 (0.1%) with both. Among 45 children who visited the ship’s childcare center, infection rate for pandemic (H1N1) 2009 was higher than that for influenza A (H3N2) viruses. Disembarked passengers reported a high level of compliance with isolation and quarantine recommendations. We found 4 subsequent cases epidemiologically linked to passengers but no evidence of sustained transmission to the community or passengers on the next cruise. Among this population of generally healthy passengers, children seemed more susceptible to pandemic (H1N1) 2009 than to influenza (H3N2) viruses. Intensive disease control measures successfully contained these outbreaks. PMID:21029531

  9. Efficacy of Influenza Vaccination and Tamiflu® Treatment – Comparative Studies with Eurasian Swine Influenza Viruses in Pigs

    PubMed Central

    Duerrwald, Ralf; Schlegel, Michael; Bauer, Katja; Vissiennon, Théophile; Wutzler, Peter; Schmidtke, Michaela

    2013-01-01

    Recent epidemiological developments demonstrated that gene segments of swine influenza A viruses can account for antigenic changes as well as reduced drug susceptibility of pandemic influenza A viruses. This raises questions about the efficacy of preventive measures against swine influenza A viruses. Here, the protective effect of vaccination was compared with that of prophylactic Tamiflu® treatment against two Eurasian swine influenza A viruses. 11-week-old pigs were infected by aerosol nebulisation with high doses of influenza virus A/swine/Potsdam/15/1981 (H1N1/1981, heterologous challenge to H1N1 vaccine strain) and A/swine/Bakum/1832/2000 (H1N2/2000, homologous challenge to H1N2 vaccine strain) in two independent trials. In each trial (i) 10 pigs were vaccinated twice with a trivalent vaccine (RESPIPORC® FLU3; 28 and 7 days before infection), (ii) another 10 pigs received 150 mg/day of Tamiflu® for 5 days starting 12 h before infection, and (iii) 12 virus-infected pigs were left unvaccinated and untreated and served as controls. Both viruses replicated efficiently in porcine respiratory organs causing influenza with fever, dyspnoea, and pneumonia. Tamiflu® treatment as well as vaccination prevented clinical signs and significantly reduced virus shedding. Whereas after homologous challenge with H1N2/2000 no infectious virus in lung and hardly any lung inflammation were detected, the virus titre was not and the lung pathology was only partially reduced in H1N1/1981, heterologous challenged pigs. Tamiflu® application did not affect these study parameters. In conclusion, all tested preventive measures provided protection against disease. Vaccination additionally prevented virus replication and histopathological changes in the lung of homologous challenged pigs. PMID:23630601

  10. Live poultry market workers are susceptible to both avian and swine influenza viruses, Guangdong Province, China.

    PubMed

    Chen, Jidang; Ma, Jun; White, Sarah K; Cao, Zhenpeng; Zhen, Yun; He, Shuyi; Zhu, Wanjun; Ke, Changwen; Zhang, Yongbiao; Su, Shuo; Zhang, Guihong

    2015-12-31

    Guangdong Province is recognized for dense populations of humans, pigs, poultry and pets. In order to evaluate the threat of viral infection faced by those working with animals, a cross-sectional, sero-epidemiological study was conducted in Guangdong between December 2013 and January 2014. Individuals working with swine, at poultry farms, or live poultry markets (LPM), and veterinarians, and controls not exposed to animals were enrolled in this study and 11 (4 human, 3 swine, 3 avian, and 1 canine) influenza A viruses were used in hemagglutination inhibition (HI) assays (7 strains) and the cross-reactivity test (9 strains) in which 5 strains were used in both tests. Univariate analysis was performed to identify which variables were significantly associated with seropositivity. Odds ratios (OR) revealed that swine workers had a significantly higher risk of elevated antibodies against A/swine/Guangdong/L6/2009(H1N1), a classical swine virus, and A/swine/Guangdong/SS1/2012(H1N1), a Eurasian avian-like swine virus than non-exposed controls. Poultry farm workers were at a higher risk of infection with avian influenza H7N9 and H9N2. LPM workers were at a higher risk of infection with 3 subtypes of avian influenza, H5N1, H7N9, and H9N2. Interestingly, the OR also indicated that LPM workers were at risk of H1N1 swine influenza virus infection, perhaps due to the presence of pigs in the LPM. While partial confounding by cross-reactive antibodies against human viruses or vaccines cannot be ruled out, our data suggests that animal exposed people as are more likely to have antibodies against animal influenza viruses. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Influenza A(H1N1)pdm09 virus infection in Norwegian swine herds 2009/10: the risk of human to swine transmission.

    PubMed

    Grøntvedt, Carl Andreas; Er, Chiek; Gjerset, Britt; Hauge, Anna Germundsson; Brun, Edgar; Jørgensen, Anne; Lium, Bjørn; Framstad, Tore

    2013-07-01

    Influenza A viruses cause respiratory infection in humans and pigs, and some serotypes can be transmitted between these species. The emergence of influenza A(H1N1)pdm09 virus infections in the spring of 2009 quickly led to a worldwide pandemic in humans, with subsequent introduction of the virus to pig populations. Following a widespread infection in the human population in Norway, influenza A(H1N1)pdm09 virus was introduced to the influenza A naïve Norwegian pig population, and within a few months pigs in more than one third of Norwegian swine herds had antibodies against the virus. A cross-sectional study was performed on all swine nucleus and multiplier herds in Norway to analyze risk factors for introduction of infection, and the preventive effects of recommended biosecurity practices. A surveillance program provided information on infection status of the study herds, and a questionnaire was administered to all 118 nucleus and multiplier herds to collect information on herd variables. The surveillance program revealed that pigs in 42% of the herds had antibodies against influenza A(H1N1)pdm09 virus. The incidence of serologically positive pigs was similar in both multiplier herds (41%) and closed nucleus herds (43%). Multivariable logistic regression showed that presence of farm staff with influenza-like illness (ILI) (OR=4.15, CI 1.5-11.4, p=0.005) and herd size (OR=1.01, CI 1-1.02, p=0.009) were risk factors for infection. The rapid and widespread seroconversion for antibodies against influenza A(H1N1)pdm09 virus in the Norwegian pig population can be explained by the emergence of a novel virus that is readily transmitted between people and swine in a largely susceptible population of humans, and an entirely naïve population of pigs. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. North American triple reassortant and Eurasian H1N1 swine influenza viruses do not readily reassort to generate a 2009 pandemic H1N1-like virus.

    PubMed

    Ma, Wenjun; Liu, Qinfang; Qiao, Chuanling; del Real, Gustavo; García-Sastre, Adolfo; Webby, Richard J; Richt, Jürgen A

    2014-03-11

    The 2009 pandemic H1N1 virus (pH1N1) was derived through reassortment of North American triple reassortant and Eurasian avian-like swine influenza viruses (SIVs). To date, when, how and where the pH1N1 arose is not understood. To investigate viral reassortment, we coinfected cell cultures and a group of pigs with or without preexisting immunity with a Eurasian H1N1 virus, A/Swine/Spain/53207/2004 (SP04), and a North American triple reassortant H1N1 virus, A/Swine/Kansas/77778/2007 (KS07). The infected pigs were cohoused with one or two groups of contact animals to investigate viral transmission. In coinfected MDCK or PK15 continuous cell lines with KS07 and SP04 viruses, more than 20 different reassortant viruses were found. In pigs without or with preexisting immunity (immunized with commercial inactivated swine influenza vaccines) and coinfected with both viruses, six or seven reassortant viruses, as well as the parental viruses, were identified in bronchoalveolar lavage fluid samples from the lungs. Interestingly, only one or two viruses transmitted to and were detected in contact animals. No reassortant containing a gene constellation similar to that of pH1N1 virus was found in either coinfected cells or pigs, indicating that the reassortment event that resulted in the generation of this virus is a rare event that likely involved specific viral strains and/or a favorable, not-yet-understood environment. IMPORTANCE The 2009 pandemic-like H1N1 virus could not be reproduced either in cell cultures or in pigs coinfected with North American triple reassortant H1N1 and Eurasian H1N1 swine influenza viruses. This finding suggests that the generation of the 2009 pandemic H1N1 virus by reassortment was a rare event that likely involved specific viral strains and unknown factors. Different reassortant viruses were detected in coinfected pigs with and without preexisting immunity, indicating that host immunity plays a relevant role in driving viral reassortment of

  13. Occurrence of a pig respiratory disease associated with swine influenza A (H1N2) virus in Tochigi Prefecture, Japan.

    PubMed

    Yoneyama, Shuji; Hayashi, Tsuyoshi; Kojima, Hirokazu; Usami, Yoshihide; Kubo, Masanori; Takemae, Nobuhiro; Uchida, Yuko; Saito, Takehiko

    2010-04-01

    In February 2008, a feeder pig herd of the affected farm in Tochigi Prefecture, Japan, showed increasing respiratory symptoms; by April, the situation worsened with 12-16 pigs dying daily. Diagnostic tests revealed the presence of H1N2 subtype of swine influenza virus (SIV) and Pasteurella multocida from nasal swab and lung emulsion. Serological tests by hemagglutination inhibition method and enzyme-linked immunosorbent assay method (ELISA; imported from U.S.A.) indicated the spread of SIV into the pig herds of the affected farm around April 2008. The severe infection and subsequent damage were considered as a result of the combined infection of SIV (H1N2) and bacteria that may have been prevalent in the pig farm. Genetic homology search of sequences for the hemagglutinin (HA) and neuraminidase (NA) genes of A/swine/Tochigi/1/08 showed high homology to Japanese SIVs (H1N2) isolated in the 2000s. Therefore, we considered that Japanese SIV (H1N2) has established an independent stable lineage and participated in infecting pig populations as one of the factors of the pig respiratory disease complex. Consistent surveillance would contribute to clarifying the prevalence of dominant SIVs.

  14. Comparative virulence of wild-type H1N1pdm09 influenza A isolates in swine.

    PubMed

    Henningson, Jamie N; Rajao, Daniela S; Kitikoon, Pravina; Lorusso, Alessio; Culhane, Marie R; Lewis, Nicola S; Anderson, Tavis K; Vincent, Amy L

    2015-03-23

    In 2009, a novel swine-origin H1N1 (H1N1pdm09) influenza A virus (IAV) reached pandemic status and was soon after detected in pigs worldwide. The objective of this study was to evaluate whether differences in the HA protein can affect pathogenicity and antigenicity of H1N1pdm09 in swine. We compared lung pathology, viral replication and shedding and the antigenic relationships of four wild-type H1N1pdm09 viruses in pigs: one human (CA/09) and three isolated in swine after the pandemic (IL/09, IL/10, and MN/10). The swine strains were selected based upon unique amino acid substitutions in the HA protein. All selected viruses resulted in mild disease and viral shedding through nasal and oral fluids, however, viral replication and the degree of pathology varied between the isolates. A/Swine/IL/5265/2010 (IL/10), with substitutions I120M, S146G, S186P, V252M, had lower viral titers in the lungs and nasal secretions and fewer lung lesions. The other two swine viruses caused respiratory pathology and replicated to titers similar to the human CA/09, although MN/10 (with mutations D45Y, K304E, A425S) had lower nasal shedding. Swine-adapted H1N1pdm09 have zoonotic potential, and have reassorted with other co-circulating swine viruses, influencing the evolution of IAV in swine globally. Further, our results suggest that amino acid changes in the HA gene have the potential to alter the virulence of H1N1pdm09 in swine. Importantly, the limited clinical signs in pigs could result in continued circulation of these viruses with other endemic swine IAVs providing opportunities for reassortment. Published by Elsevier B.V.

  15. Transmissibility of Variant Influenza From Swine to Humans: A Modeling Approach

    PubMed Central

    Wong, Karen K.; Gambhir, Manoj; Finelli, Lyn; Swerdlow, David L.; Ostroff, Stephen; Reed, Carrie

    2015-01-01

    Background Respiratory illness was reported among humans and swine at an agricultural fair in 2011; 3 human infections with an influenza A(H3N2) variant (H3N2v) virus were confirmed. Using epidemiologic investigation data, we sought to estimate H3N2v transmissibility from swine to humans. Methods We developed a model of H3N2v transmission among swine and humans and fit it to data from a cohort of 100 agricultural club members reporting swine contact to estimate transmissibility. A sensitivity analysis was performed varying H3N2v prevalence in the club cohort. Using the best-fit transmission probability, we simulated the number of swine-acquired infections among all fair attendees. Results We estimated the best-fit probability of swine-to-human H3N2v transmission per minute of swine contact. Applying this probability to 14 910 people with swine contact at the fair, we estimate that there were 80 (95% confidence interval [CI], 40–133) H3N2v infections among persons aged <20 years and 58 (95% CI, 29–96) H3N2v infections among person aged ≥20 years. Conclusions Using early data from investigation of a new virus with unclear transmission properties, we estimated the transmissibility of H3N2v from swine to humans and the burden of H3N2v among fair attendees. Although the risk of H3N2v virus infection is small for fair attendees with minimal swine contact, large populations attend agricultural events each year, and human cases will likely occur when infected swine are present. PMID:23794727

  16. Adaptive evolution during the establishment of European avian-like H1N1 influenza A virus in swine.

    PubMed

    Joseph, Udayan; Vijaykrishna, Dhanasekaran; Smith, Gavin J D; Su, Yvonne C F

    2018-04-01

    An H1N1 subtype influenza A virus with all eight gene segments derived from wild birds (including mallards), ducks and chickens, caused severe disease outbreaks in swine populations in Europe beginning in 1979 and successfully adapted to form the European avian-like swine (EA-swine) influenza lineage. Genes of the EA-swine lineage that are clearly segregated from its closest avian relatives continue to circulate in swine populations globally and represent a unique opportunity to study the adaptive process of an avian-to-mammalian cross-species transmission. Here, we used a relaxed molecular clock model to test whether the EA-swine virus originated through the introduction of a single avian ancestor as an entire genome, followed by an analysis of host-specific selection pressures among different gene segments. Our data indicated independent introduction of gene segments via transmission of avian viruses into swine followed by reassortment events that occurred at least 1-4 years prior to the EA-swine outbreak. All EA-swine gene segments exhibit greater selection pressure than avian viruses, reflecting both adaptive pressures and relaxed selective constraints that are associated with host switching. Notably, we identified key amino acid mutations in the viral surface proteins (H1 and N1) that play a role in adaptation to new hosts. Following the establishment of EA-swine lineage, we observed an increased frequency of intrasubtype reassortment of segments compared to the earlier strains that has been associated with adaptive amino acid replacements, disease severity and vaccine escape. Taken together, our study provides key insights into the adaptive changes in viral genomes following the transmission of avian influenza viruses to swine and the early establishment of the EA-swine lineage.

  17. Cross-protection against European swine influenza viruses in the context of infection immunity against the 2009 pandemic H1N1 virus: studies in the pig model of influenza.

    PubMed

    Qiu, Yu; De Hert, Karl; Van Reeth, Kristien

    2015-09-24

    Pigs are natural hosts for the same influenza virus subtypes as humans and are a valuable model for cross-protection studies with influenza. In this study, we have used the pig model to examine the extent of virological protection between a) the 2009 pandemic H1N1 (pH1N1) virus and three different European H1 swine influenza virus (SIV) lineages, and b) these H1 viruses and a European H3N2 SIV. Pigs were inoculated intranasally with representative strains of each virus lineage with 6- and 17-week intervals between H1 inoculations and between H1 and H3 inoculations, respectively. Virus titers in nasal swabs and/or tissues of the respiratory tract were determined after each inoculation. There was substantial though differing cross-protection between pH1N1 and other H1 viruses, which was directly correlated with the relatedness in the viral hemagglutinin (HA) and neuraminidase (NA) proteins. Cross-protection against H3N2 was almost complete in pigs with immunity against H1N2, but was weak in H1N1/pH1N1-immune pigs. In conclusion, infection with a live, wild type influenza virus may offer substantial cross-lineage protection against viruses of the same HA and/or NA subtype. True heterosubtypic protection, in contrast, appears to be minimal in natural influenza virus hosts. We discuss our findings in the light of the zoonotic and pandemic risks of SIVs.

  18. 76 FR 79203 - Prospective Grant of Exclusive License: Veterinary Biological Products for Swine Influenza Vaccines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-21

    ... Exclusive License: Veterinary Biological Products for Swine Influenza Vaccines AGENCY: National Institutes....7. The invention relates to compositions and methods of use as Veterinary Influenza Vaccines... to humans. This technology describes DNA vaccines against influenza serotypes H5N1, H1N1, H3N2, and...

  19. Initial psychological responses to Influenza A, H1N1 ("Swine flu").

    PubMed

    Goodwin, Robin; Haque, Shamsul; Neto, Felix; Myers, Lynn B

    2009-10-06

    The outbreak of the pandemic flu, Influenza A H1N1 (Swine Flu) in early 2009, provided a major challenge to health services around the world. Previous pandemics have led to stockpiling of goods, the victimisation of particular population groups, and the cancellation of travel and the boycotting of particular foods (e.g. pork). We examined initial behavioural and attitudinal responses towards Influenza A, H1N1 ("Swine flu") in the six days following the WHO pandemic alert level 5, and regional differences in these responses. 328 respondents completed a cross-sectional Internet or paper-based questionnaire study in Malaysia (N = 180) or Europe (N = 148). Measures assessed changes in transport usage, purchase of preparatory goods for a pandemic, perceived risk groups, indicators of anxiety, assessed estimated mortality rates for seasonal flu, effectiveness of seasonal flu vaccination, and changes in pork consumption 26% of the respondents were 'very concerned' about being a flu victim (42% Malaysians, 5% Europeans, p < .001). 36% reported reduced public transport use (48% Malaysia, 22% Europe, p < .001), 39% flight cancellations (56% Malaysia, 17% Europe, p < .001). 8% had purchased preparatory materials (e.g. face masks: 8% Malaysia, 7% Europe), 41% Malaysia (15% Europe) intended to do so (p < .001). 63% of Europeans, 19% of Malaysians had discussed the pandemic with friends (p < .001). Groups seen as at 'high risk' of infection included the immune compromised (mentioned by 87% respondents), pig farmers (70%), elderly (57%), prostitutes/highly sexually active (53%), and the homeless (53%). In data collected only in Europe, 64% greatly underestimated the mortality rates of seasonal flu, 26% believed seasonal flu vaccination gave protection against swine flu. 7% had reduced/stopped eating pork. 3% had purchased anti-viral drugs for use at home, while 32% intended to do so if the pandemic worsened. Initial responses to Influenza A show large regional differences in

  20. Appearance of reassortant European avian-origin H1 influenza A viruses of swine in Vietnam.

    PubMed

    Takemae, N; Nguyen, P T; Le, V T; Nguyen, T N; To, T L; Nguyen, T D; Pham, V P; Vo, H V; Le, Q V T; Do, H T; Nguyen, D T; Uchida, Y; Saito, T

    2018-03-06

    Three subtypes-H1N1, H1N2 and H3N2-of influenza A viruses of swine (IAVs-S) are currently endemic in swine worldwide, but there is considerable genotypic diversity among each subtype and limited geographical distribution. Through IAVs-S monitoring in Vietnam, two H1N2 influenza A viruses were isolated from healthy pigs in Ba Ria-Vung Tau Province, Southern Vietnam, on 2 December 2016. BLAST and phylogenetic analyses revealed that their HA and NA genes were derived from those of European avian-like H1N2 IAVs-S that contained avian-origin H1 and human-like N2 genes, and were particularly closely related to those of IAVs-S circulating in the Netherlands, Germany or Denmark. In addition, the internal genes of these Vietnamese isolates were derived from human A(H1N1)pdm09 viruses, suggesting that the Vietnamese H1N2 IAVs-S are reassortants between European H1N2 IAVs-S and human A(H1N1)pdm09v. The appearance of European avian-like H1N2 IAVs-S in Vietnam marks their first transmission outside Europe. Our results and statistical analyses of the number of live pigs imported into Vietnam suggest that the European avian-like H1N2 IAVs-S may have been introduced into Vietnam with their hosts through international trade. These findings highlight the importance of quarantining imported pigs to impede the introduction of new IAVs-S. © 2018 Blackwell Verlag GmbH.

  1. Poly I:C adjuvanted inactivated swine influenza vaccine induces heterologous protective immunity in pigs.

    PubMed

    Thomas, Milton; Wang, Zhao; Sreenivasan, Chithra C; Hause, Ben M; Gourapura J Renukaradhya; Li, Feng; Francis, David H; Kaushik, Radhey S; Khatri, Mahesh

    2015-01-15

    Swine influenza is widely prevalent in swine herds in North America and Europe causing enormous economic losses and a public health threat. Pigs can be infected by both avian and mammalian influenza viruses and are sources of generation of reassortant influenza viruses capable of causing pandemics in humans. Current commercial vaccines provide satisfactory immunity against homologous viruses; however, protection against heterologous viruses is not adequate. In this study, we evaluated the protective efficacy of an intranasal Poly I:C adjuvanted UV inactivated bivalent swine influenza vaccine consisting of Swine/OH/24366/07 H1N1 and Swine/CO/99 H3N2, referred as PAV, in maternal antibody positive pigs against an antigenic variant and a heterologous swine influenza virus challenge. Groups of three-week-old commercial-grade pigs were immunized intranasally with PAV or a commercial vaccine (CV) twice at 2 weeks intervals. Three weeks after the second immunization, pigs were challenged with the antigenic variant Swine/MN/08 H1N1 (MN08) and the heterologous Swine/NC/10 H1N2 (NC10) influenza virus. Antibodies in serum and respiratory tract, lung lesions, virus shedding in nasal secretions and virus load in lungs were assessed. Intranasal administration of PAV induced challenge viruses specific-hemagglutination inhibition- and IgG antibodies in the serum and IgA and IgG antibodies in the respiratory tract. Importantly, intranasal administration of PAV provided protection against the antigenic variant MN08 and the heterologous NC10 swine influenza viruses as evidenced by significant reductions in lung virus load, gross lung lesions and significantly reduced shedding of challenge viruses in nasal secretions. These results indicate that Poly I:C or its homologues may be effective as vaccine adjuvants capable of generating cross-protective immunity against antigenic variants/heterologous swine influenza viruses in pigs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Efficacy of a pandemic (H1N1) 2009 virus vaccine in pigs against the pandemic influenza virus is superior to commercially available swine influenza vaccines.

    PubMed

    Loeffen, W L A; Stockhofe, N; Weesendorp, E; van Zoelen-Bos, D; Heutink, R; Quak, S; Goovaerts, D; Heldens, J G M; Maas, R; Moormann, R J; Koch, G

    2011-09-28

    In April 2009 a new influenza A/H1N1 strain, currently named "pandemic (H1N1) influenza 2009" (H1N1v), started the first official pandemic in humans since 1968. Several incursions of this virus in pig herds have also been reported from all over the world. Vaccination of pigs may be an option to reduce exposure of human contacts with infected pigs, thereby preventing cross-species transfer, but also to protect pigs themselves, should this virus cause damage in the pig population. Three swine influenza vaccines, two of them commercially available and one experimental, were therefore tested and compared for their efficacy against an H1N1v challenge. One of the commercial vaccines is based on an American classical H1N1 influenza strain, the other is based on a European avian H1N1 influenza strain. The experimental vaccine is based on reassortant virus NYMC X179A (containing the hemagglutinin (HA) and neuraminidase (NA) genes of A/California/7/2009 (H1N1v) and the internal genes of A/Puerto Rico/8/34 (H1N1)). Excretion of infectious virus was reduced by 0.5-3 log(10) by the commercial vaccines, depending on vaccine and sample type. Both vaccines were able to reduce virus replication especially in the lower respiratory tract, with less pathological lesions in vaccinated and subsequently challenged pigs than in unvaccinated controls. In pigs vaccinated with the experimental vaccine, excretion levels of infectious virus in nasal and oropharyngeal swabs, were at or below 1 log(10)TCID(50) per swab and lasted for only 1 or 2 days. An inactivated vaccine containing the HA and NA of an H1N1v is able to protect pigs from an infection with H1N1v, whereas swine influenza vaccines that are currently available are of limited efficaciousness. Whether vaccination of pigs against H1N1v will become opportune remains to be seen and will depend on future evolution of this strain in the pig population. Close monitoring of the pig population, focussing on presence and evolution of

  3. Evolution-informed forecasting of seasonal influenza A (H3N2).

    PubMed

    Du, Xiangjun; King, Aaron A; Woods, Robert J; Pascual, Mercedes

    2017-10-25

    Interpandemic or seasonal influenza A, currently subtypes H3N2 and H1N1, exacts an enormous annual burden both in terms of human health and economic impact. Incidence prediction ahead of season remains a challenge largely because of the virus' antigenic evolution. We propose a forecasting approach that incorporates evolutionary change into a mechanistic epidemiological model. The proposed models are simple enough that their parameters can be estimated from retrospective surveillance data. These models link amino acid sequences of hemagglutinin epitopes with a transmission model for seasonal H3N2 influenza, also informed by H1N1 levels. With a monthly time series of H3N2 incidence in the United States for more than 10 years, we demonstrate the feasibility of skillful prediction for total cases ahead of season, with a tendency to underpredict monthly peak epidemic size, and an accurate real-time forecast for the 2016/2017 influenza season. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  4. Characterization of an Artificial Swine-Origin Influenza Virus with the Same Gene Combination as H1N1/2009 Virus: A Genesis Clue of Pandemic Strain

    PubMed Central

    Pu, Juan; Fan, Lihong; Shi, Weimin; Hu, Yanxin; Yang, Jun; Xu, Qi; Wang, Jingjing; Hou, Dongjun; Ma, Guangpeng; Liu, Jinhua

    2011-01-01

    Pandemic H1N1/2009 influenza virus, derived from a reassortment of avian, human, and swine influenza viruses, possesses a unique gene segment combination that had not been detected previously in animal and human populations. Whether such a gene combination could result in the pathogenicity and transmission as H1N1/2009 virus remains unclear. In the present study, we used reverse genetics to construct a reassortant virus (rH1N1) with the same gene combination as H1N1/2009 virus (NA and M genes from a Eurasian avian-like H1N1 swine virus and another six genes from a North American triple-reassortant H1N2 swine virus). Characterization of rH1N1 in mice showed that this virus had higher replicability and pathogenicity than those of the seasonal human H1N1 and Eurasian avian-like swine H1N1 viruses, but was similar to the H1N1/2009 and triple-reassortant H1N2 viruses. Experiments performed on guinea pigs showed that rH1N1 was not transmissible, whereas pandemic H1N1/2009 displayed efficient transmissibility. To further determine which gene segment played a key role in transmissibility, we constructed a series of reassortants derived from rH1N1 and H1N1/2009 viruses. Direct contact transmission studies demonstrated that the HA and NS genes contributed to the transmission of H1N1/2009 virus. Second, the HA gene of H1N1/2009 virus, when combined with the H1N1/2009 NA gene, conferred efficient contact transmission among guinea pigs. The present results reveal that not only gene segment reassortment but also amino acid mutation were needed for the generation of the pandemic influenza virus. PMID:21799774

  5. Characterization of an artificial swine-origin influenza virus with the same gene combination as H1N1/2009 virus: a genesis clue of pandemic strain.

    PubMed

    Zhao, Xueli; Sun, Yipeng; Pu, Juan; Fan, Lihong; Shi, Weimin; Hu, Yanxin; Yang, Jun; Xu, Qi; Wang, Jingjing; Hou, Dongjun; Ma, Guangpeng; Liu, Jinhua

    2011-01-01

    Pandemic H1N1/2009 influenza virus, derived from a reassortment of avian, human, and swine influenza viruses, possesses a unique gene segment combination that had not been detected previously in animal and human populations. Whether such a gene combination could result in the pathogenicity and transmission as H1N1/2009 virus remains unclear. In the present study, we used reverse genetics to construct a reassortant virus (rH1N1) with the same gene combination as H1N1/2009 virus (NA and M genes from a Eurasian avian-like H1N1 swine virus and another six genes from a North American triple-reassortant H1N2 swine virus). Characterization of rH1N1 in mice showed that this virus had higher replicability and pathogenicity than those of the seasonal human H1N1 and Eurasian avian-like swine H1N1 viruses, but was similar to the H1N1/2009 and triple-reassortant H1N2 viruses. Experiments performed on guinea pigs showed that rH1N1 was not transmissible, whereas pandemic H1N1/2009 displayed efficient transmissibility. To further determine which gene segment played a key role in transmissibility, we constructed a series of reassortants derived from rH1N1 and H1N1/2009 viruses. Direct contact transmission studies demonstrated that the HA and NS genes contributed to the transmission of H1N1/2009 virus. Second, the HA gene of H1N1/2009 virus, when combined with the H1N1/2009 NA gene, conferred efficient contact transmission among guinea pigs. The present results reveal that not only gene segment reassortment but also amino acid mutation were needed for the generation of the pandemic influenza virus.

  6. Evidence for Cross-species Influenza A Virus Transmission Within Swine Farms, China: A One Health, Prospective Cohort Study.

    PubMed

    Ma, Mai-Juan; Wang, Guo-Lin; Anderson, Benjamin D; Bi, Zhen-Qiang; Lu, Bing; Wang, Xian-Jun; Wang, Chuang-Xin; Chen, Shan-Hui; Qian, Yan-Hua; Song, Shao-Xia; Li, Min; Lednicky, John A; Zhao, Teng; Wu, Meng-Na; Cao, Wu-Chun; Gray, Gregory C

    2018-02-01

    Our understanding of influenza A virus transmission between humans and pigs is limited. Beginning in 2015, we used a One Health approach and serial sampling to prospectively study 299 swine workers and 100 controls, their 9000 pigs, and 6 pig farm environments in China for influenza A viruses (IAVs) using molecular, culture, and immunological techniques. Study participants were closely monitored for influenza-like illness (ILI) events. Upon enrollment, swine workers had higher serum neutralizing antibody titers against swine H1N1 and higher nasal wash total immunoglobulin A (IgA) and specific IgA titers against swine H1N1 and H3N2 viruses. Over a period of 12 months, IAVs were detected by quantitative reverse-transcription polymerase chain reaction in 46 of 396 (11.6%) environmental swabs, 235 of 3300 (7.1%) pig oral secretion, 23 of 396 (5.8%) water, 20 of 396 (5.1%) aerosol, and 19 of 396 (4.8%) fecal-slurry specimens. Five of 32 (15.6%) participants with ILI events had nasopharyngeal swab specimens that were positive for IAV, and 17 (53.1%) demonstrated 4-fold rises in neutralization titers against a swine virus. Reassorted Eurasian avian-lineage H1N1, A(H1N1)pdm09-like, and swine-lineage H3N2 viruses were identified in pig farms. The A(H1N1)pdm09-like H1N1 viruses identified in swine were nearly genetically identical to the human H1N1 viruses isolated from the participants with ILI. There was considerable evidence of A(H1N1)pdm09-like, swine-lineage H1N1, and swine-lineage H3N2 viruses circulating, likely reassorting, and likely crossing species within the pig farms. These data suggest that stronger surveillance for novel influenza virus emergence within swine farms is imperative. © The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  7. Triple-reassortant swine influenza A (H1) in humans in the United States, 2005-2009.

    PubMed

    Shinde, Vivek; Bridges, Carolyn B; Uyeki, Timothy M; Shu, Bo; Balish, Amanda; Xu, Xiyan; Lindstrom, Stephen; Gubareva, Larisa V; Deyde, Varough; Garten, Rebecca J; Harris, Meghan; Gerber, Susan; Vagasky, Susan; Smith, Forrest; Pascoe, Neal; Martin, Karen; Dufficy, Deborah; Ritger, Kathy; Conover, Craig; Quinlisk, Patricia; Klimov, Alexander; Bresee, Joseph S; Finelli, Lyn

    2009-06-18

    Triple-reassortant swine influenza A (H1) viruses--containing genes from avian, human, and swine influenza viruses--emerged and became enzootic among pig herds in North America during the late 1990s. We report the clinical features of the first 11 sporadic cases of infection of humans with triple-reassortant swine influenza A (H1) viruses reported to the Centers for Disease Control and Prevention, occurring from December 2005 through February 2009, until just before the current epidemic of swine-origin influenza A (H1N1) among humans. These data were obtained from routine national influenza surveillance reports and from joint case investigations by public and animal health agencies. The median age of the 11 patients was 10 years (range, 16 months to 48 years), and 4 had underlying health conditions. Nine of the patients had had exposure to pigs, five through direct contact and four through visits to a location where pigs were present but without contact. In another patient, human-to-human transmission was suspected. The range of the incubation period, from the last known exposure to the onset of symptoms, was 3 to 9 days. Among the 10 patients with known clinical symptoms, symptoms included fever (in 90%), cough (in 100%), headache (in 60%), and diarrhea (in 30%). Complete blood counts were available for four patients, revealing leukopenia in two, lymphopenia in one, and thrombocytopenia in another. Four patients were hospitalized, two of whom underwent invasive mechanical ventilation. Four patients received oseltamivir, and all 11 recovered from their illness. From December 2005 until just before the current human epidemic of swine-origin influenza viruses, there was sporadic infection with triple-reassortant swine influenza A (H1) viruses in persons with exposure to pigs in the United States. Although all the patients recovered, severe illness of the lower respiratory tract and unusual influenza signs such as diarrhea were observed in some patients, including

  8. Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru.

    PubMed

    Tinoco, Yeny O; Montgomery, Joel M; Kasper, Mathew R; Nelson, Martha I; Razuri, Hugo; Guezala, Maria C; Azziz-Baumgartner, Eduardo; Widdowson, Marc-Alain; Barnes, John; Gilman, Robert H; Bausch, Daniel G; Gonzalez, Armando E

    2016-01-01

    We aimed to determine the frequency of pH1N1 transmission between humans and swine on backyard farms in Tumbes, Peru. Two-year serial cross-sectional study comprising four sampling periods: March 2009 (pre-pandemic), October 2009 (peak of the pandemic in Peru), April 2010 (1st post-pandemic period), and October 2011 (2nd post-pandemic period). Backyard swine serum, tracheal swabs, and lung sample were collected during each sampling period. We assessed current and past pH1N1 infection in swine through serological testing, virus culture, and RT-PCR and compared the results with human incidence data from a population-based active surveillance cohort study in Peru. Among 1303 swine sampled, the antibody prevalence to pH1N1 was 0% pre-pandemic, 8% at the peak of the human pandemic (October 2009), and 24% in April 2010 and 1% in October 2011 (post-pandemic sampling periods). Trends in swine seropositivity paralleled those seen in humans in Tumbes. The pH1N1 virus was isolated from three pigs during the peak of the pandemic. Phylogenetic analysis revealed that these viruses likely represent two separate human-to-swine transmission events in backyard farm settings. Our findings suggest that human-to-swine pH1N1 transmission occurred during the pandemic among backyard farms in Peru, emphasizing the importance of interspecies transmission in backyard pig populations. Continued surveillance for influenza viruses in backyard farms is warranted. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  9. Protocol: Transmission and prevention of influenza in Hutterites: Zoonotic transmission of influenza A: swine & swine workers

    PubMed Central

    2009-01-01

    to St. Jude where sera will be examined for antibodies to swine and human influenza virus strains or reassortants. Full length sequencing of all eight genes from the human and swine influenza isolates will be performed so that detailed comparisons can be performed between them. Discussion The declaration of pandemic influenza in June 2009, caused by a novel H1N1 virus that includes avian, swine and human genes, highlights the importance of investigations of human/swine influenza transmission. PMID:19922661

  10. Influenza A(H3N2) Outbreak at Transit Center at Manas, Kyrgyzstan, 2014

    DTIC Science & Technology

    2015-01-01

    influenza-like illness symptoms from 3 December 2013 through 28 February 2014. There were 85 specimens positive for influenza (18 influenza A( H1N1 ...February 2014. Th ere were 85 specimens positive for infl uenza (18 infl uenza A( H1N1 )pdm09, 65 infl uenza A(H3N2), one infl uenza A/not subtyped, and one...Health Organization reports, both infl uenza A( H1N1 )pdm09 and A(H3N2) viruses were circulating during the time of this outbreak.9 Th is is

  11. Sensitivity of influenza rapid diagnostic tests to H5N1 and 2009 pandemic H1N1 viruses.

    PubMed

    Sakai-Tagawa, Yuko; Ozawa, Makoto; Tamura, Daisuke; Le, Mai thi Quynh; Nidom, Chairul A; Sugaya, Norio; Kawaoka, Yoshihiro

    2010-08-01

    Simple and rapid diagnosis of influenza is useful for making treatment decisions in the clinical setting. Although many influenza rapid diagnostic tests (IRDTs) are available for the detection of seasonal influenza virus infections, their sensitivity for other viruses, such as H5N1 viruses and the recently emerged swine origin pandemic (H1N1) 2009 virus, remains largely unknown. Here, we examined the sensitivity of 20 IRDTs to various influenza virus strains, including H5N1 and 2009 pandemic H1N1 viruses. Our results indicate that the detection sensitivity to swine origin H1N1 viruses varies widely among IRDTs, with some tests lacking sufficient sensitivity to detect the early stages of infection when the virus load is low.

  12. Evolution-informed forecasting of seasonal influenza A (H3N2)

    PubMed Central

    Du, Xiangjun; King, Aaron A.; Woods, Robert J.; Pascual, Mercedes

    2018-01-01

    Inter-pandemic or seasonal influenza exacts an enormous annual burden both in terms of human health and economic impact. Incidence prediction ahead of season remains a challenge largely because of the virus’ antigenic evolution. We propose here a forecasting approach that incorporates evolutionary change into a mechanistic epidemiological model. The proposed models are simple enough that their parameters can be estimated from retrospective surveillance data. These models link amino-acid sequences of hemagglutinin epitopes with a transmission model for seasonal H3N2 influenza, also informed by H1N1 levels. With a monthly time series of H3N2 incidence in the United States over 10 years, we demonstrate the feasibility of prediction ahead of season and an accurate real-time forecast for the 2016/2017 influenza season. PMID:29070700

  13. Retrospective swine influenza serological surveillance in the four highest pig density provinces of Thailand before the introduction of the 2009 pandemic Influenza A virus subtype H1N1 using various antibody detection assays.

    PubMed

    Sreta, Donruethai; Jittimanee, Suphattra; Charoenvisal, Nataya; Amonsin, Alongkorn; Kitikoon, Pravina; Thanawongnuwech, Roongroje

    2013-01-01

    Genetic characterization of the hemagglutinin gene of the 6 selected Thai Swine influenza virus (SIV) isolates (4 H1 and 2 H3 isolates) used in the establishment of a hemagglutination inhibition (HI) assay was analyzed. Based on the phylogenetic analysis, Thai SIVs could be divided into 3 clusters of the H1 viruses (clusters I and II belonging to classical swine H1α, and cluster III belonging to classical swine H1γ), and 2 clusters of the H3 viruses both belonging to human-like 1970s. The serological results indicated that swH1N1-06 (H1 cluster I) is a suitable representative SIV for the HI test antigen to detect H1 SIV-specific antibodies in the Thai swine population, while both swH3N2-05 and swH3N2-07 should be used for Thai H3 SIV-specific antibody detection. The HI test results of swine sera collected from pigs in the 4 highest pig population provinces of Thailand indicated that the percentage of pigs seropositive to swH3N2-07 was highest compared to swH1N1-06, swH1N1-09, and swH3N2-05 (85.4%, 50.1%, 18.6%, and 15.8%, respectively). It should be noted that countries lacking SIV genetic information should be concerned with determining the most suitable HI test antigens to use when performing the tests due to the genetic variation and limited cross-reaction of SIVs. The results of the current study demonstrated that HI tests should be implemented with the suitable field strains as the representative test antigen to ascertain accurate SIV serostatus in Thailand and that test antigens should be genetically analyzed and compared with circulating strains regularly.

  14. The future of influenza A virus vaccines for swine

    USDA-ARS?s Scientific Manuscript database

    Economic losses due to influenza A virus (IAV) infections are substantial and a global problem, ranking among the top three major health challenges in the swine industry. Currently, H1 and H3 subtypes circulate in pigs globally associated with different combinations of N1 and N2 subtypes; however, t...

  15. The Molecular Determinants of Antibody Recognition and Antigenic Drift in the H3 Hemagglutinin of Swine Influenza A Virus

    PubMed Central

    Abente, Eugenio J.; Santos, Jefferson; Lewis, Nicola S.; Gauger, Phillip C.; Stratton, Jered; Skepner, Eugene; Rajao, Daniela S.

    2016-01-01

    ABSTRACT Influenza A virus (IAV) of the H3 subtype is an important respiratory pathogen that affects both humans and swine. Vaccination to induce neutralizing antibodies against the surface glycoprotein hemagglutinin (HA) is the primary method used to control disease. However, due to antigenic drift, vaccine strains must be periodically updated. Six of the 7 positions previously identified in human seasonal H3 (positions 145, 155, 156, 158, 159, 189, and 193) were also indicated in swine H3 antigenic evolution. To experimentally test the effect on virus antigenicity of these 7 positions, substitutions were introduced into the HA of an isogenic swine lineage virus. We tested the antigenic effect of these introduced substitutions by using hemagglutination inhibition (HI) data with monovalent swine antisera and antigenic cartography to evaluate the antigenic phenotype of the mutant viruses. Combinations of substitutions within the antigenic motif caused significant changes in antigenicity. One virus mutant that varied at only two positions relative to the wild type had a >4-fold reduction in HI titers compared to homologous antisera. Potential changes in pathogenesis and transmission of the double mutant were evaluated in pigs. Although the double mutant had virus shedding titers and transmissibility comparable to those of the wild type, it caused a significantly lower percentage of lung lesions. Elucidating the antigenic effects of specific amino acid substitutions at these sites in swine H3 IAV has important implications for understanding IAV evolution within pigs as well as for improved vaccine development and control strategies in swine. IMPORTANCE A key component of influenza virus evolution is antigenic drift mediated by the accumulation of amino acid substitutions in the hemagglutinin (HA) protein, resulting in escape from prior immunity generated by natural infection or vaccination. Understanding which amino acid positions of the HA contribute to the ability

  16. Cellular and humoral cross-immunity against two H3N2v influenza strains in presumably unexposed healthy and HIV-infected subjects.

    PubMed

    Agrati, Chiara; Castilletti, Concetta; Cimini, Eleonora; Lapa, Daniele; Quartu, Serena; Caglioti, Claudia; Lanini, Simone; Cattoli, Giovanni; Martini, Federico; Ippolito, Giuseppe; Capobianchi, Maria R

    2014-01-01

    Human cases of infection due to a novel swine-origin variant of influenza A virus subtype H3N2 (H3N2v) have recently been identified in the United States. Pre-existing humoral and cellular immunity has been recognized as one of the key factors in limiting the infection burden of an emerging influenza virus strain, contributing to restrict its circulation and to mitigate clinical presentation. Aim of this study was to assess humoral and cell-mediated cross immune responses to H3N2v in immuno-competent (healthy donors, n = 45) and immuno-compromised hosts (HIV-infected subjects, n = 46) never exposed to H3N2v influenza strain. Humoral response against i) H3N2v (A/H3N2/Ind/08/11), ii) animal vaccine H3N2 strain (A/H3N2/Min/11/10), and iii) pandemic H1N1 virus (A/H1N1/Cal/07/09) was analysed by hemagglutination inhibition assay; cell-mediated response against the same influenza strains was analysed by ELISpot assay. A large proportion of healthy and HIV subjects displayed cross-reacting humoral and cellular immune responses against two H3N2v strains, suggesting the presence of B- and T-cell clones able to recognize epitopes from emerging viral strains in both groups. Specifically, humoral response was lower in HIV subjects than in HD, and a specific age-related pattern of antibody response against different influenza strains was observed both in HD and in HIV. Cellular immune response was similar between HD and HIV groups and no relationship with age was reported. Finally, no correlation between humoral and cellular immune response was observed. Overall, a high prevalence of HD and HIV patients showing cross reactive immunity against two H3N2v strains was observed, with a slightly lower proportion in HIV persons. Other studies focused on HIV subjects at different stages of diseases are needed in order to define how cross immunity can be affected by advanced immunosuppression.

  17. PA-X protein decreases replication and pathogenicity of swine influenza virus in cultured cells and mouse models.

    PubMed

    Gong, Xiao-Qian; Sun, Ying-Feng; Ruan, Bao-Yang; Liu, Xiao-Min; Wang, Qi; Yang, Hai-Ming; Wang, Shuai-Yong; Zhang, Peng; Wang, Xiu-Hui; Shan, Tong-Ling; Tong, Wu; Zhou, Yan-Jun; Li, Guo-Xin; Zheng, Hao; Tong, Guang-Zhi; Yu, Hai

    2017-06-01

    Swine influenza viruses have been circulating in pigs throughout world and might be potential threats to human health. PA-X protein is a newly discovered protein produced from the PA gene by ribosomal frameshifting and the effects of PA-X on the 1918 H1N1, the pandemic 2009 H1N1, the highly pathogenic avian H5N1 and the avian H9N2 influenza viruses have been reported. However, the role of PA-X in the pathogenesis of swine influenza virus is still unknown. In this study, we rescued the H1N1 wild-type (WT) classical swine influenza virus (A/Swine/Guangdong/1/2011 (H1N1)) and H1N1 PA-X deficient virus containing mutations at the frameshift motif, and compared their replication properties and pathogenicity of swine influenza virus in vitro and in vivo. Our results show that the expression of PA-X inhibits virus replication and polymerase activity in cultured cells and decreases virulence in mouse models. Therefore, our study demonstrates that PA-X protein acts as a negative virulence regulator for classical H1N1 swine influenza virus and decreases virulence by inhibiting viral replication and polymerase activity, deepening our understanding of the pathogenesis of swine influenza virus. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Infection of mice with a human influenza A/H3N2 virus induces protective immunity against lethal infection with influenza A/H5N1 virus.

    PubMed

    Kreijtz, J H C M; Bodewes, R; van den Brand, J M A; de Mutsert, G; Baas, C; van Amerongen, G; Fouchier, R A M; Osterhaus, A D M E; Rimmelzwaan, G F

    2009-08-06

    The transmission of highly pathogenic avian influenza (HPAI) A viruses of the H5N1 subtype from poultry to man and the high case fatality rate fuels the fear for a pandemic outbreak caused by these viruses. However, prior infections with seasonal influenza A/H1N1 and A/H3N2 viruses induce heterosubtypic immunity that could afford a certain degree of protection against infection with the HPAI A/H5N1 viruses, which are distantly related to the human influenza A viruses. To assess the protective efficacy of such heterosubtypic immunity mice were infected with human influenza virus A/Hong Kong/2/68 (H3N2) 4 weeks prior to a lethal infection with HPAI virus A/Indonesia/5/05 (H5N1). Prior infection with influenza virus A/Hong Kong/2/68 reduced clinical signs, body weight loss, mortality and virus replication in the lungs as compared to naive mice infected with HPAI virus A/Indonesia/5/05. Priming by infection with respiratory syncytial virus, a non-related virus did not have a beneficial effect on the outcome of A/H5N1 infections, indicating that adaptive immune responses were responsible for the protective effect. In mice primed by infection with influenza A/H3N2 virus cytotoxic T lymphocytes (CTL) specific for NP(366-374) epitope ASNENMDAM and PA(224-232) SCLENFRAYV were observed. A small proportion of these CTL was cross-reactive with the peptide variant derived from the influenza A/H5N1 virus (ASNENMEVM and SSLENFRAYV respectively) and upon challenge infection with the influenza A/H5N1 virus cross-reactive CTL were selectively expanded. These CTL, in addition to those directed to conserved epitopes, shared by the influenza A/H3N2 and A/H5N1 viruses, most likely contributed to accelerated clearance of the influenza A/H5N1 virus infection. Although also other arms of the adaptive immune response may contribute to heterosubtypic immunity, the induction of virus-specific CTL may be an attractive target for development of broad protective vaccines. Furthermore the

  19. A(H1N1)pdm09 influenza infection: vaccine inefficiency.

    PubMed

    Friedman, Nehemya; Drori, Yaron; Pando, Rakefet; Glatman-Freedman, Aharona; Sefty, Hanna; Bassal, Ravit; Stein, Yaniv; Shohat, Tamy; Mendelson, Ella; Hindiyeh, Musa; Mandelboim, Michal

    2017-05-16

    The last influenza pandemic, caused by the swine A(H1N1)pdm09 influenza virus, began in North America at 2009. Since then, the World Health Organization (WHO) recommended integration of the swine-based virus A/California/07/2009 strain in yearly vaccinations. Yet, infections with A(H1N1)pdm09 have continued in subsequent years. The reasons for this are currently unknown. During the 2015-2016 influenza season, we noted an increased prevalence of A(H1N1)pdm09 influenza virus infection in Israel. Our phylogenetic analysis indicated that the circulating A(H1N1)pdm09 strains belonged to 6B.1 and 6B.2 clades and differed from the vaccinating strain, with approximately 18 amino acid differences found between the circulating strains and the immunizing A/California/07/2009 strain. Hemmaglutination inhibition (HI) assays demonstrated higher antibodies titer against the A/California/07/2009 vaccinating strain as compared to the circulating Israeli strains. We thus suggest that the current vaccination was not sufficiently effective and propose inclusion of the current circulating A(H1N1)pdm09 influenza viruses in the annual vaccine composition.

  20. Assessment of transmission, pathogenesis and adaptation of H2 subtype influenza viruses in ferrets.

    PubMed

    Pappas, Claudia; Yang, Hua; Carney, Paul J; Pearce, Melissa B; Katz, Jacqueline M; Stevens, James; Tumpey, Terrence M

    2015-03-01

    After their disappearance from the human population in 1968, influenza H2 viruses have continued to circulate in the natural avian reservoir. The isolation of this virus subtype from multiple bird species as well as swine highlights the need to better understand the potential of these viruses to spread and cause disease in humans. Here we analyzed the virulence, transmissibility and receptor-binding preference of two avian influenza H2 viruses (H2N2 and H2N3) and compared them to a swine H2N3 (A/swine/Missouri/2124514/2006 [swMO]), and a human H2N2 (A/England/10/1967 [Eng/67]) virus using the ferret model as a mammalian host. Both avian H2 viruses possessed the capacity to spread efficiently between cohoused ferrets, and the swine (swMO) and human (Eng/67) viruses transmitted to naïve ferrets by respiratory droplets. Further characterization of the swMO hemagglutinin (HA) by x-ray crystallography and glycan microarray array identified receptor-specific adaptive mutations. As influenza virus quasispecies dynamics during transmission have not been well characterized, we sequenced nasal washes collected during transmission studies to better understand experimental adaptation of H2 HA. The avian H2 viruses isolated from ferret nasal washes contained mutations in the HA1, including a Gln226Leu substitution, which is a mutation associated with α2,6 sialic acid (human-like) binding preference. These results suggest that the molecular structure of HA in viruses of the H2 subtype continue to have the potential to adapt to a mammalian host and become transmissible, after acquiring additional genetic markers. Published by Elsevier Inc.

  1. Assessment of transmission, pathogenesis and adaptation of H2 subtype influenza viruses in ferrets

    PubMed Central

    Pappas, Claudia; Yang, Hua; Carney, Paul J.; Pearce, Melissa B.; Katz, Jacqueline M.; Stevens, James; Tumpey, Terrence M.

    2018-01-01

    After their disappearance from the human population in 1968, influenza H2 viruses have continued to circulate in the natural avian reservoir. The isolation of this virus subtype from multiple bird species as well as swine highlights the need to better understand the potential of these viruses to spread and cause disease in humans. Here we analyzed the virulence, transmissibility and receptor-binding preference of two avian influenza H2 viruses (H2N2 and H2N3) and compared them to a swine H2N3 (A/swine/Missouri/2124514/2006 [swMO]), and a human H2N2 (A/England/10/1967 [Eng/67]) virus using the ferret model as a mammalian host. Both avian H2 viruses possessed the capacity to spread efficiently between cohoused ferrets, and the swine (swMO) and human (Eng/67) viruses transmitted to naïve ferrets by respiratory droplets. Further characterization of the swMO hemagglutinin (HA) by x-ray crystallography and glycan microarray array identified receptor-specific adaptive mutations. As influenza virus quasispecies dynamics during transmission have not been well characterized, we sequenced nasal washes collected during transmission studies to better understand experimental adaptation of H2 HA. The avian H2 viruses isolated from ferret nasal washes contained mutations in the HA1, including a Gln226Leu substitution, which is a mutation associated with α2,6 sialic acid (human-like) binding preference. These results suggest that the molecular structure of HA in viruses of the H2 subtype continue to have the potential to adapt to a mammalian host and become transmissible, after acquiring additional genetic markers. PMID:25659818

  2. Imported pigs may have introduced the first classical swine influenza viruses into Mainland China.

    PubMed

    Zhu, Wenfei; Yang, Shuai; Guo, Yuanji; Yang, Lei; Bai, Tian; Yu, Zaijiang; Li, Xiaodan; Li, Ming; Guo, Junfeng; Wang, Dayan; Gao, Rongbao; Dong, Libo; Zou, Shumei; Li, Zi; Wang, Min; Shu, Yuelong

    2013-07-01

    The first classical swine influenza A H1N1 viruses were isolated in Mainland China in 1991. To aid surveillance of swine influenza viruses as part of pandemic preparedness, we sought to identify their origin. We sequenced and phylogenically analyzed 19 swine influenza viruses isolated in 1991 and 1992 in China and compared them with viruses isolated from other regions during the same period. All 19 swine influenza viruses analyzed in our study shared the highest similarity with the classical swine influenza virus A/Swine/Maryland/23239/1991 (H1N1). Phylogenetic trees of eight segmented genes exhibited similar topology, with all segments in the cluster of classical swine influenza viruses. In addition, antigenic analysis also indicated that the tested isolated were related to classical swine influenza isolates. Classical swine H1N1 influenza viruses were predominant in Beijing pig herds during this period. Since both antibody and virus detections did not indicate the presence of CS H1N1 before 1991 in Mainland China, we combined with the data on pigs imported to and exported from China and concluded that these viruses might spread to China via pigs imported from North America and that they could affect the genetic evolution and transmission dynamics of swine influenza viruses in Hong Kong. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. European Surveillance Network for Influenza in Pigs: Surveillance Programs, Diagnostic Tools and Swine Influenza Virus Subtypes Identified in 14 European Countries from 2010 to 2013

    PubMed Central

    Simon, Gaëlle; Larsen, Lars E.; Dürrwald, Ralf; Foni, Emanuela; Harder, Timm; Van Reeth, Kristien; Markowska-Daniel, Iwona; Reid, Scott M.; Dan, Adam; Maldonado, Jaime; Huovilainen, Anita; Billinis, Charalambos; Davidson, Irit; Agüero, Montserrat; Vila, Thaïs; Hervé, Séverine; Breum, Solvej Østergaard; Chiapponi, Chiara; Urbaniak, Kinga; Kyriakis, Constantinos S.; Brown, Ian H.; Loeffen, Willie

    2014-01-01

    Swine influenza causes concern for global veterinary and public health officials. In continuing two previous networks that initiated the surveillance of swine influenza viruses (SIVs) circulating in European pigs between 2001 and 2008, a third European Surveillance Network for Influenza in Pigs (ESNIP3, 2010–2013) aimed to expand widely the knowledge of the epidemiology of European SIVs. ESNIP3 stimulated programs of harmonized SIV surveillance in European countries and supported the coordination of appropriate diagnostic tools and subtyping methods. Thus, an extensive virological monitoring, mainly conducted through passive surveillance programs, resulted in the examination of more than 9 000 herds in 17 countries. Influenza A viruses were detected in 31% of herds examined from which 1887 viruses were preliminary characterized. The dominating subtypes were the three European enzootic SIVs: avian-like swine H1N1 (53.6%), human-like reassortant swine H1N2 (13%) and human-like reassortant swine H3N2 (9.1%), as well as pandemic A/H1N1 2009 (H1N1pdm) virus (10.3%). Viruses from these four lineages co-circulated in several countries but with very different relative levels of incidence. For instance, the H3N2 subtype was not detected at all in some geographic areas whereas it was still prevalent in other parts of Europe. Interestingly, H3N2-free areas were those that exhibited highest frequencies of circulating H1N2 viruses. H1N1pdm viruses were isolated at an increasing incidence in some countries from 2010 to 2013, indicating that this subtype has become established in the European pig population. Finally, 13.9% of the viruses represented reassortants between these four lineages, especially between previous enzootic SIVs and H1N1pdm. These novel viruses were detected at the same time in several countries, with increasing prevalence. Some of them might become established in pig herds, causing implications for zoonotic infections. PMID:25542013

  4. European surveillance network for influenza in pigs: surveillance programs, diagnostic tools and Swine influenza virus subtypes identified in 14 European countries from 2010 to 2013.

    PubMed

    Simon, Gaëlle; Larsen, Lars E; Dürrwald, Ralf; Foni, Emanuela; Harder, Timm; Van Reeth, Kristien; Markowska-Daniel, Iwona; Reid, Scott M; Dan, Adam; Maldonado, Jaime; Huovilainen, Anita; Billinis, Charalambos; Davidson, Irit; Agüero, Montserrat; Vila, Thaïs; Hervé, Séverine; Breum, Solvej Østergaard; Chiapponi, Chiara; Urbaniak, Kinga; Kyriakis, Constantinos S; Brown, Ian H; Loeffen, Willie

    2014-01-01

    Swine influenza causes concern for global veterinary and public health officials. In continuing two previous networks that initiated the surveillance of swine influenza viruses (SIVs) circulating in European pigs between 2001 and 2008, a third European Surveillance Network for Influenza in Pigs (ESNIP3, 2010-2013) aimed to expand widely the knowledge of the epidemiology of European SIVs. ESNIP3 stimulated programs of harmonized SIV surveillance in European countries and supported the coordination of appropriate diagnostic tools and subtyping methods. Thus, an extensive virological monitoring, mainly conducted through passive surveillance programs, resulted in the examination of more than 9 000 herds in 17 countries. Influenza A viruses were detected in 31% of herds examined from which 1887 viruses were preliminary characterized. The dominating subtypes were the three European enzootic SIVs: avian-like swine H1N1 (53.6%), human-like reassortant swine H1N2 (13%) and human-like reassortant swine H3N2 (9.1%), as well as pandemic A/H1N1 2009 (H1N1pdm) virus (10.3%). Viruses from these four lineages co-circulated in several countries but with very different relative levels of incidence. For instance, the H3N2 subtype was not detected at all in some geographic areas whereas it was still prevalent in other parts of Europe. Interestingly, H3N2-free areas were those that exhibited highest frequencies of circulating H1N2 viruses. H1N1pdm viruses were isolated at an increasing incidence in some countries from 2010 to 2013, indicating that this subtype has become established in the European pig population. Finally, 13.9% of the viruses represented reassortants between these four lineages, especially between previous enzootic SIVs and H1N1pdm. These novel viruses were detected at the same time in several countries, with increasing prevalence. Some of them might become established in pig herds, causing implications for zoonotic infections.

  5. Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan

    PubMed Central

    Sugaya, Norio; Shinjoh, Masayoshi; Kawakami, Chiharu; Yamaguchi, Yoshio; Yoshida, Makoto; Baba, Hiroaki; Ishikawa, Mayumi; Kono, Mio; Sekiguchi, Shinichiro; Kimiya, Takahisa; Mitamura, Keiko; Fujino, Motoko; Komiyama, Osamu; Yoshida, Naoko; Tsunematsu, Kenichiro; Narabayashi, Atsushi; Nakata, Yuji; Sato, Akihiro; Taguchi, Nobuhiko; Fujita, Hisayo; Toki, Machiko; Myokai, Michiko; Ookawara, Ichiro; Takahashi, Takao

    2016-01-01

    The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case–control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE. PMID:27784529

  6. Alternative reverse genetics system for influenza viruses based on a synthesized swine 45S rRNA promoter.

    PubMed

    Wang, Kai; Huang, Qi; Yang, Zhiwei; Qi, Kezong; Liu, Hongmei; Chen, Hongjun

    2017-08-01

    We generated an alternative reverse genetics (RG) system based on a synthesized swine 45S rRNA promoter to rescue the H3N2 subtype swine influenza virus. All eight flanking segment cassettes of A/swine/Henan/7/2010 (H3N2) were amplified with ambisense expression elements from RG plasmids. All segments were then recombined with the pHC2014 vector, which contained the synthesized swine 45S rRNA promoter (spol1) and its terminal sequence (t1) in a pcDNA3 backbone. As a result, we obtained a set of RG plasmids carrying the corresponding eight-segment cassettes. We efficiently generated the H3N2 virus after transfection into 293T/PK15, PK15, and 293T cells. The efficiency of spol1-driven influenza virus rescue in PK15 cells was similar to that in 293T cells by titration using the human pol1 RG system. Our approach suggests that an alternative spol1-based RG system can produce influenza viruses.

  7. Swine flu (H1N1 influenza): awareness profile of visitors of swine flu screening booths in Belgaum city, Karnataka.

    PubMed

    Viveki, R G; Halappanavar, A B; Patil, M S; Joshi, A V; Gunagi, Praveena; Halki, Sunanda B

    2012-06-01

    The 2009 flu pandemic was a global outbreak of a new strain of H1N1 influenza virus often referred colloquially as "swine flu". The objectives of the study were: (1) To know the sociodemographic and awareness profile of visitors attending swine flu screening booths. (2) To reveal sources of information. The present cross-sectional study was undertaken among the visitors (18 years and above) attending swine flu screening booths organised within the Belgaum city during Ganesh festival from 28-08-2009 to 03-09-2009 by interviewing them using predesigned, pretested structured questionnaire on swine flu. The data was collected and analysed using SPSS software programme for windows (version 16). Chi-square test was applied. Out of 206 visitors, 132 (64.1%) were males and 107 (51.9%) were in the age group of 30-49 years; 183 (88.8%) had heard about swine flu. More than a third of the visitors (38.3%) disclosed that there was a vaccine to prevent swine flu. Majority responded that it could be transmitted by being in close proximity to pigs (49.0%) and by eating pork (51.5%). Newspaper/magazine (64.6%), television (61.7%), and public posters/pamphlets (44.2%) were common sources of information. The present study revealed that doctors/public health workers have played little role in creating awareness in the community. The improved communication between doctors and the community would help to spread correct information about the disease and the role that the community can play in controlling the spread of the disease.

  8. Genomic characterization of H1N2 swine influenza viruses in Italy.

    PubMed

    Moreno, Ana; Chiapponi, Chiara; Boniotti, Maria Beatrice; Sozzi, Enrica; Foni, Emanuela; Barbieri, Ilaria; Zanoni, Maria Grazia; Faccini, Silvia; Lelli, Davide; Cordioli, Paolo

    2012-05-04

    Three subtypes (H1N1, H1N2, and H3N2) are currently diffused worldwide in pigs. The H1N2 subtype was detected for the first time in Italian pigs in 1998. To investigate the genetic characteristics and the molecular evolution of this subtype in Italy, we conducted a phylogenetic analysis of whole genome sequences of 26 strains isolated from 1998 to 2010. Phylogenetic analysis of HA and NA genes showed differences between the older (1998-2003) and the more recent strains (2003-2010). The older isolates were closely related to the established European H1N2 lineage, whereas the more recent isolates possessed a different NA deriving from recent human H3N2 viruses. Two other reassortant H1N2 strains have been detected: A/sw/It/22530/02 has the HA gene that is closely related to H1N1 viruses; A/sw/It/58769/10 is an uncommon strain with an HA that is closely related to H1N1 and an NA similar to H3N2 SIVs. Amino acid analysis revealed interesting features: a deletion of two amino acids (146-147) in the HA gene of the recent isolates and two strains isolated in 1998; the presence of the uncommon aa change (N66S), in the PB1-F2 protein in strains isolated from 2009 to 2010, which is said to have contributed to the increased virulence. These results demonstrate the importance of pigs as mixing vessels for animal and human influenza and show the presence and establishment of reassortant strains involving human viruses in pigs in Italy. These findings also highlighted different genomic characteristics of the NA gene the recent Italian strains compared to circulating European viruses. Published by Elsevier B.V.

  9. Serological evidence for avian H9N2 influenza virus infections among Romanian agriculture workers.

    PubMed

    Coman, Alexandru; Maftei, Daniel N; Krueger, Whitney S; Heil, Gary L; Friary, John A; Chereches, Razvan M; Sirlincan, Emanuela; Bria, Paul; Dragnea, Claudiu; Kasler, Iosif; Gray, Gregory C

    2013-12-01

    In recent years, wild birds have introduced multiple highly pathogenic avian influenza (HPAI) H5N1 virus infections in Romanian poultry. In 2005 HPAI infections were widespread among domestic poultry and anecdotal reports suggested domestic pigs may also have been exposed. We sought to examine evidence for zoonotic influenza infections among Romanian agriculture workers. Between 2009 and 2010, 363 adult participants were enrolled in a cross-sectional, seroepidemiological study. Confined animal feeding operation (CAFO) swine workers in Tulcea and small, traditional backyard farmers in Cluj-Napoca were enrolled, as well as a non-animal exposed control group from Cluj-Napoca. Enrollment sera were examined for serological evidence of previous infection with 9 avian and 3 human influenza virus strains. Serologic assays showed no evidence of previous infection with 7 low pathogenic avian influenza viruses or with HPAI H5N1. However, 33 participants (9.1%) had elevated microneutralization antibody titers against avian-like A/Hong Kong/1073/1999(H9N2), 5 with titers ≥ 1:80 whom all reported exposure to poultry. Moderate poultry exposure was significantly associated with elevated titers after controlling for the subjects' age (adjusted OR = 3.6; 95% CI, 1.1-12.1). There was no evidence that previous infection with human H3N2 or H2N2 viruses were confounding the H9N2 seroreactivity. These data suggest that H9N2 virus may have circulated in Romanian poultry and occasionally infected man. Copyright © 2013 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  10. Substitution of D701N in the PB2 protein could enhance the viral replication and pathogenicity of Eurasian avian-like H1N1 swine influenza viruses.

    PubMed

    Liu, Suli; Zhu, Wenfei; Feng, Zhaomin; Gao, Rongbao; Guo, Junfeng; Li, Xiyan; Liu, Jia; Wang, Dayan; Shu, Yuelong

    2018-05-02

    Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses (SIVs) have become predominant in pig populations in China and have recently been reported to have the most potential to raise the next pandemic in humans. The mutation D701N in the PB2 protein, which accounts for 31% of H1N1 SIVs, has previously been shown to contribute to the adaptation of the highly pathogenic H5N1 or H7N7 avian influenza viruses in mammals. However, little is known of the effects of this substitution on the EA H1N1 viruses. Herein, we investigated the contributions of 701N in the PB2 protein to an EA H1N1 SIV (A/Hunan/42443/2015(H1N1), HuN EA-H1N1), which had 701D in the PB2 protein. Our results found that viral polymerase activity, viral replication, and pathogenicity in mice were indeed enhanced due to the introduction of 701N into the PB2 protein, and the increased viral growth was partly mediated by the host factor importin-α7. Thus, substantial attention should be paid to the D701N mutation in pig populations.

  11. Pathogenicity of swine influenza viruses possessing an avian or swine-origin PB2 polymerase gene evaluated in mouse and pig models.

    PubMed

    Ma, Wenjun; Lager, Kelly M; Li, Xi; Janke, Bruce H; Mosier, Derek A; Painter, Laura E; Ulery, Eva S; Ma, Jingqun; Lekcharoensuk, Porntippa; Webby, Richard J; Richt, Jürgen A

    2011-02-05

    PB2 627K is a determinant of influenza host range and contributes to the pathogenicity of human-, avian-, and mouse-adapted influenza viruses in the mouse model. Here we used mouse and pig models to analyze the contribution of a swine-origin and avian-origin PB2 carrying either 627K or 627E in the background of the classical swine H1N1 (A/Swine/Iowa/15/30; 1930) virus. The results showed PB2 627K is crucial for virulence in the mouse model, independent of whether PB2 is derived from an avian or swine influenza virus (SIV). In the pig model, PB2 627E decreases pathogenicity of the classical 1930 SIV when it contains the swine-origin PB2, but not when it possesses the avian-origin PB2. Our study suggests the pathogenicity of SIVs with different PB2 genes and mutation of codon 627 in mice does not correlate with the pathogenicity of the same SIVs in the natural host, the pig. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Molecular Epidemiology and Evolution of Influenza Viruses Circulating within European Swine between 2009 and 2013.

    PubMed

    Watson, Simon J; Langat, Pinky; Reid, Scott M; Lam, Tommy Tsan-Yuk; Cotten, Matthew; Kelly, Michael; Van Reeth, Kristien; Qiu, Yu; Simon, Gaëlle; Bonin, Emilie; Foni, Emanuela; Chiapponi, Chiara; Larsen, Lars; Hjulsager, Charlotte; Markowska-Daniel, Iwona; Urbaniak, Kinga; Dürrwald, Ralf; Schlegel, Michael; Huovilainen, Anita; Davidson, Irit; Dán, Ádám; Loeffen, Willie; Edwards, Stephanie; Bublot, Michel; Vila, Thais; Maldonado, Jaime; Valls, Laura; Brown, Ian H; Pybus, Oliver G; Kellam, Paul

    2015-10-01

    The emergence in humans of the A(H1N1)pdm09 influenza virus, a complex reassortant virus of swine origin, highlighted the importance of worldwide influenza virus surveillance in swine. To date, large-scale surveillance studies have been reported for southern China and North America, but such data have not yet been described for Europe. We report the first large-scale genomic characterization of 290 swine influenza viruses collected from 14 European countries between 2009 and 2013. A total of 23 distinct genotypes were identified, with the 7 most common comprising 82% of the incidence. Contrasting epidemiological dynamics were observed for two of these genotypes, H1huN2 and H3N2, with the former showing multiple long-lived geographically isolated lineages, while the latter had short-lived geographically diffuse lineages. At least 32 human-swine transmission events have resulted in A(H1N1)pdm09 becoming established at a mean frequency of 8% across European countries. Notably, swine in the United Kingdom have largely had a replacement of the endemic Eurasian avian virus-like ("avian-like") genotypes with A(H1N1)pdm09-derived genotypes. The high number of reassortant genotypes observed in European swine, combined with the identification of a genotype similar to the A(H3N2)v genotype in North America, underlines the importance of continued swine surveillance in Europe for the purposes of maintaining public health. This report further reveals that the emergences and drivers of virus evolution in swine differ at the global level. The influenza A(H1N1)pdm09 virus contains a reassortant genome with segments derived from separate virus lineages that evolved in different regions of the world. In particular, its neuraminidase and matrix segments were derived from the Eurasian avian virus-like ("avian-like") lineage that emerged in European swine in the 1970s. However, while large-scale genomic characterization of swine has been reported for southern China and North America, no

  13. Molecular Epidemiology and Evolution of Influenza Viruses Circulating within European Swine between 2009 and 2013

    PubMed Central

    Watson, Simon J.; Langat, Pinky; Reid, Scott M.; Lam, Tommy Tsan-Yuk; Cotten, Matthew; Kelly, Michael; Van Reeth, Kristien; Qiu, Yu; Simon, Gaëlle; Bonin, Emilie; Foni, Emanuela; Chiapponi, Chiara; Larsen, Lars; Hjulsager, Charlotte; Markowska-Daniel, Iwona; Urbaniak, Kinga; Dürrwald, Ralf; Schlegel, Michael; Huovilainen, Anita; Davidson, Irit; Dán, Ádám; Loeffen, Willie; Edwards, Stephanie; Bublot, Michel; Vila, Thais; Maldonado, Jaime; Valls, Laura; Brown, Ian H.; Pybus, Oliver G.

    2015-01-01

    ABSTRACT The emergence in humans of the A(H1N1)pdm09 influenza virus, a complex reassortant virus of swine origin, highlighted the importance of worldwide influenza virus surveillance in swine. To date, large-scale surveillance studies have been reported for southern China and North America, but such data have not yet been described for Europe. We report the first large-scale genomic characterization of 290 swine influenza viruses collected from 14 European countries between 2009 and 2013. A total of 23 distinct genotypes were identified, with the 7 most common comprising 82% of the incidence. Contrasting epidemiological dynamics were observed for two of these genotypes, H1huN2 and H3N2, with the former showing multiple long-lived geographically isolated lineages, while the latter had short-lived geographically diffuse lineages. At least 32 human-swine transmission events have resulted in A(H1N1)pdm09 becoming established at a mean frequency of 8% across European countries. Notably, swine in the United Kingdom have largely had a replacement of the endemic Eurasian avian virus-like (“avian-like”) genotypes with A(H1N1)pdm09-derived genotypes. The high number of reassortant genotypes observed in European swine, combined with the identification of a genotype similar to the A(H3N2)v genotype in North America, underlines the importance of continued swine surveillance in Europe for the purposes of maintaining public health. This report further reveals that the emergences and drivers of virus evolution in swine differ at the global level. IMPORTANCE The influenza A(H1N1)pdm09 virus contains a reassortant genome with segments derived from separate virus lineages that evolved in different regions of the world. In particular, its neuraminidase and matrix segments were derived from the Eurasian avian virus-like (“avian-like”) lineage that emerged in European swine in the 1970s. However, while large-scale genomic characterization of swine has been reported for southern

  14. C-reactive protein, haptoglobin, serum amyloid A and pig major acute phase protein response in pigs simultaneously infected with H1N1 swine influenza virus and Pasteurella multocida

    PubMed Central

    2013-01-01

    Background Swine influenza (SI) is an acute respiratory disease caused by swine influenza virus (SIV). Swine influenza is generally characterized by acute onset of fever and respiratory symptoms. The most frequent complications of influenza are secondary bacterial pneumonia. The objective of this work was to study the acute phase proteins (APP) responses after coinfection of piglets with H1N1 swine influenza virus (SwH1N1) and Pasteurella multocida (Pm) in order to identify whether the individual APP response correlate with disease severity and whether APP could be used as markers of the health status of coinfected pigs. Results In all coinfected pigs clinical sings, including fever, coughing and dyspnea, were seen. Viral shedding was observed from 2 to 7 dpi. The mean level of antibodies against Pm dermonecrotoxin in infected piglets increase significantly from 7 dpi. Anti-SwH1N1 antibodies in the serum were detected from 7 dpi. The concentration of C-reactive protein (CRP) increased significantly at 1 dpi as compared to control pigs, and remained significantly higher to 3 dpi. Level of serum amyloid A (SAA) was significantly higher from 2 to 3 dpi. Haptoglobin (Hp) was significantly elevated from 3 dpi to the end of study, while pig major acute phase protein (Pig-MAP) from 3 to 7 dpi. The concentrations of CRP, Hp and SAA significantly increased before specific antibodies were detected. Positive correlations were found between serum concentration of Hp and SAA and lung scores, and between clinical score and concentrations of Pig-MAP and SAA. Conclusions The results of current study confirmed that monitoring of APP may revealed ongoing infection, and in this way may be useful in selecting clinically healthy pigs (i.e. before integration into an uninfected herd). Present results corroborated our previous findings that SAA could be a potentially useful indicator in experimental infection studies (e.g. vaccine efficiency investigations) or as a marker for disease

  15. C-reactive protein, haptoglobin, serum amyloid A and pig major acute phase protein response in pigs simultaneously infected with H1N1 swine influenza virus and Pasteurella multocida.

    PubMed

    Pomorska-Mól, Małgorzata; Markowska-Daniel, Iwona; Kwit, Krzysztof; Stępniewska, Katarzyna; Pejsak, Zygmunt

    2013-01-18

    Swine influenza (SI) is an acute respiratory disease caused by swine influenza virus (SIV). Swine influenza is generally characterized by acute onset of fever and respiratory symptoms. The most frequent complications of influenza are secondary bacterial pneumonia. The objective of this work was to study the acute phase proteins (APP) responses after coinfection of piglets with H1N1 swine influenza virus (SwH1N1) and Pasteurella multocida (Pm) in order to identify whether the individual APP response correlate with disease severity and whether APP could be used as markers of the health status of coinfected pigs. In all coinfected pigs clinical sings, including fever, coughing and dyspnea, were seen. Viral shedding was observed from 2 to 7 dpi. The mean level of antibodies against Pm dermonecrotoxin in infected piglets increase significantly from 7 dpi. Anti-SwH1N1 antibodies in the serum were detected from 7 dpi. The concentration of C-reactive protein (CRP) increased significantly at 1 dpi as compared to control pigs, and remained significantly higher to 3 dpi. Level of serum amyloid A (SAA) was significantly higher from 2 to 3 dpi. Haptoglobin (Hp) was significantly elevated from 3 dpi to the end of study, while pig major acute phase protein (Pig-MAP) from 3 to 7 dpi. The concentrations of CRP, Hp and SAA significantly increased before specific antibodies were detected. Positive correlations were found between serum concentration of Hp and SAA and lung scores, and between clinical score and concentrations of Pig-MAP and SAA. The results of current study confirmed that monitoring of APP may revealed ongoing infection, and in this way may be useful in selecting clinically healthy pigs (i.e. before integration into an uninfected herd). Present results corroborated our previous findings that SAA could be a potentially useful indicator in experimental infection studies (e.g. vaccine efficiency investigations) or as a marker for disease severity, because of correlation

  16. Epidemiology of pandemic influenza A/H1N1 virus during 2009-2010 in Taiwan.

    PubMed

    Lan, Yu-Ching; Su, Mei-Chi; Chen, Chao-Hsien; Huang, Su-Hua; Chen, Wan-Li; Tien, Ni; Lin, Cheng-Wen

    2013-10-01

    Outbreak of swine-origin influenza A/H1N1 virus (pdmH1N1) occurred in 2009. Taiwanese authorities implemented nationwide vaccinations with pdmH1N1-specific inactivated vaccine as of November 2009. This study evaluates prevalence, HA phylogenetic relationship, and transmission dynamic of influenza A and B viruses in Taiwan in 2009-2010. Respiratory tract specimens were analyzed for influenza A and B viruses. The pdmH1N1 peaked in November 2009, was predominant from August 2009 to January 2010, then sharply dropped in February 2010. Significant prevalence peaks of influenza B in April-June of 2010 and H3N2 virus in July and August were observed. Highest percentage of pdmH1N1- and H3N2-positive cases appeared among 11-15-year-olds; influenza B-positive cases were dominant among those 6-10 years old. Maximum likelihood phylogenetic trees showed 11 unique clusters of pdmH1N1, seasonal H3N2 influenza A and B viruses, as well as transmission clusters and mixed infections of influenza strains in Taiwan. The 2009 pdmH1N1 virus was predominant in Taiwan from August 2009 to January 2010; seasonal H3N2 influenza A and B viruses exhibited small prevalence peaks after nationwide vaccinations. Phylogenetic evidence indicated transmission clusters and multiple independent clades of co-circulating influenza A and B strains in Taiwan. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Reassortant Eurasian Avian-Like Influenza A(H1N1) Virus from a Severely Ill Child, Hunan Province, China, 2015.

    PubMed

    Zhu, Wenfei; Zhang, Hong; Xiang, Xingyu; Zhong, Lili; Yang, Lei; Guo, Junfeng; Xie, Yiran; Li, Fangcai; Deng, Zhihong; Feng, Hong; Huang, Yiwei; Hu, Shixiong; Xu, Xin; Zou, Xiaohui; Li, Xiaodan; Bai, Tian; Chen, Yongkun; Li, Zi; Li, Junhua; Shu, Yuelong

    2016-11-01

    In 2015, a novel influenza A(H1N1) virus was isolated from a boy in China who had severe pneumonia. The virus was a genetic reassortant of Eurasian avian-like influenza A(H1N1) (EA-H1N1) virus. The hemagglutinin, neuraminidase, and matrix genes of the reassortant virus were highly similar to genes in EA-H1N1 swine influenza viruses, the polybasic 1 and 2, polymerase acidic, and nucleoprotein genes originated from influenza A(H1N1)pdm09 virus, and the nonstructural protein gene derived from classical swine influenza A(H1N1) (CS H1N1) virus. In a mouse model, the reassortant virus, termed influenza A/Hunan/42443/2015(H1N1) virus, showed higher infectivity and virulence than another human EA-H1N1 isolate, influenza A/Jiangsu/1/2011(H1N1) virus. In the respiratory tract of mice, virus replication by influenza A/Hunan/42443/2015(H1N1) virus was substantially higher than that by influenza A/Jiangsu/1/2011(H1N1) virus. Human-to-human transmission of influenza A/Hunan/42443/2015(H1N1) virus has not been detected; however, given the circulation of novel EA-H1N1 viruses in pigs, enhanced surveillance should be instituted among swine and humans.

  18. Reassortant Eurasian Avian-Like Influenza A(H1N1) Virus from a Severely Ill Child, Hunan Province, China, 2015

    PubMed Central

    Zhu, Wenfei; Zhang, Hong; Xiang, Xingyu; Zhong, Lili; Yang, Lei; Guo, Junfeng; Xie, Yiran; Li, Fangcai; Deng, Zhihong; Feng, Hong; Huang, Yiwei; Hu, Shixiong; Xu, Xin; Zou, Xiaohui; Li, Xiaodan; Bai, Tian; Chen, Yongkun; Li, Zi

    2016-01-01

    In 2015, a novel influenza A(H1N1) virus was isolated from a boy in China who had severe pneumonia. The virus was a genetic reassortant of Eurasian avian-like influenza A(H1N1) (EA-H1N1) virus. The hemagglutinin, neuraminidase, and matrix genes of the reassortant virus were highly similar to genes in EA-H1N1 swine influenza viruses, the polybasic 1 and 2, polymerase acidic, and nucleoprotein genes originated from influenza A(H1N1)pdm09 virus, and the nonstructural protein gene derived from classical swine influenza A(H1N1) (CS H1N1) virus. In a mouse model, the reassortant virus, termed influenza A/Hunan/42443/2015(H1N1) virus, showed higher infectivity and virulence than another human EA-H1N1 isolate, influenza A/Jiangsu/1/2011(H1N1) virus. In the respiratory tract of mice, virus replication by influenza A/Hunan/42443/2015(H1N1) virus was substantially higher than that by influenza A/Jiangsu/1/2011(H1N1) virus. Human-to-human transmission of influenza A/Hunan/42443/2015(H1N1) virus has not been detected; however, given the circulation of novel EA-H1N1 viruses in pigs, enhanced surveillance should be instituted among swine and humans. PMID:27767007

  19. Immunization of pigs with an attenuated pseudorabies virus recombinant expressing the haemagglutinin of pandemic swine origin H1N1 influenza A virus.

    PubMed

    Klingbeil, Katharina; Lange, Elke; Teifke, Jens P; Mettenleiter, Thomas C; Fuchs, Walter

    2014-04-01

    Pigs can be severely harmed by influenza, and represent important reservoir hosts, in which new human pathogens such as the recent pandemic swine-origin H1N1 influenza A virus can arise by mutation and reassortment of genome segments. To obtain novel, safe influenza vaccines for pigs, and to investigate the antigen-specific immune response, we modified an established live-virus vaccine against Aujeszky's disease of swine, pseudorabies virus (PrV) strain Bartha (PrV-Ba), to serve as vector for the expression of haemagglutinin (HA) of swine-origin H1N1 virus. To facilitate transgene insertion, the genome of PrV-Ba was cloned as a bacterial artificial chromosome. HA expression occurred under control of the human or murine cytomegalovirus immediate early promoters (P-HCMV, P-MCMV), but could be substantially enhanced by synthetic introns and adaptation of the codon usage to that of PrV. However, despite abundant expression, the heterologous glycoprotein was not detectably incorporated into mature PrV particles. Replication of HA-expressing PrV in cell culture was only slightly affected compared to that of the parental virus strain. A single immunization of pigs with the PrV vector expressing the codon-optimized HA gene under control of P-MCMV induced high levels of HA-specific antibodies. The vaccinated animals were protected from clinical signs after challenge with a related swine-origin H1N1 influenza A virus, and challenge virus shedding was significantly reduced.

  20. Differential interactions of virulent and non-virulent H. parasuis strains with naïve or swine influenza virus pre-infected dendritic cells

    PubMed Central

    2012-01-01

    Pigs possess a microbiota in the upper respiratory tract that includes Haemophilus parasuis. Pigs are also considered the reservoir of influenza viruses and infection with this virus commonly results in increased impact of bacterial infections, including those by H. parasuis. However, the mechanisms involved in host innate responses towards H. parasuis and their implications in a co-infection with influenza virus are unknown. Therefore, the ability of a non-virulent H. parasuis serovar 3 (SW114) and a virulent serovar 5 (Nagasaki) strains to interact with porcine bone marrow dendritic cells (poBMDC) and their modulation in a co-infection with swine influenza virus (SwIV) H3N2 was examined. At 1 hour post infection (hpi), SW114 interaction with poBMDC was higher than that of Nagasaki, while at 8 hpi both strains showed similar levels of interaction. The co-infection with H3N2 SwIV and either SW114 or Nagasaki induced higher levels of IL-1β, TNF-α, IL-6, IL-12 and IL-10 compared to mock or H3N2 SwIV infection alone. Moreover, IL-12 and IFN-α secretion differentially increased in cells co-infected with H3N2 SwIV and Nagasaki. These results pave the way for understanding the differences in the interaction of non-virulent and virulent strains of H. parasuis with the swine immune system and their modulation in a viral co-infection. PMID:23157617

  1. Differential interactions of virulent and non-virulent H. parasuis strains with naïve or swine influenza virus pre-infected dendritic cells.

    PubMed

    Mussá, Tufária; Rodríguez-Cariño, Carolina; Sánchez-Chardi, Alejandro; Baratelli, Massimiliano; Costa-Hurtado, Mar; Fraile, Lorenzo; Domínguez, Javier; Aragon, Virginia; Montoya, María

    2012-11-16

    Pigs possess a microbiota in the upper respiratory tract that includes Haemophilus parasuis. Pigs are also considered the reservoir of influenza viruses and infection with this virus commonly results in increased impact of bacterial infections, including those by H. parasuis. However, the mechanisms involved in host innate responses towards H. parasuis and their implications in a co-infection with influenza virus are unknown. Therefore, the ability of a non-virulent H. parasuis serovar 3 (SW114) and a virulent serovar 5 (Nagasaki) strains to interact with porcine bone marrow dendritic cells (poBMDC) and their modulation in a co-infection with swine influenza virus (SwIV) H3N2 was examined. At 1 hour post infection (hpi), SW114 interaction with poBMDC was higher than that of Nagasaki, while at 8 hpi both strains showed similar levels of interaction. The co-infection with H3N2 SwIV and either SW114 or Nagasaki induced higher levels of IL-1β, TNF-α, IL-6, IL-12 and IL-10 compared to mock or H3N2 SwIV infection alone. Moreover, IL-12 and IFN-α secretion differentially increased in cells co-infected with H3N2 SwIV and Nagasaki. These results pave the way for understanding the differences in the interaction of non-virulent and virulent strains of H. parasuis with the swine immune system and their modulation in a viral co-infection.

  2. Introduction, Evolution, and Dissemination of Influenza A Viruses in Exhibition Swine in the United States during 2009 to 2013

    PubMed Central

    Nelson, Martha I.; Stucker, Karla M.; Schobel, Seth A.; Dugan, Vivien G.; Nelson, Sarah W.; Sreevatsan, Srinand; Killian, Mary L.; Nolting, Jacqueline M.; Wentworth, David E.

    2016-01-01

    ABSTRACT The swine-human interface created at agricultural fairs, along with the generation of and maintenance of influenza A virus diversity in exhibition swine, presents an ongoing threat to public health. Nucleotide sequences of influenza A virus isolates collected from exhibition swine in Ohio (n = 262) and Indiana (n = 103) during 2009 to 2013 were used to investigate viral evolution and movement within this niche sector of the swine industry. Phylogenetic and Bayesian analyses were employed to identify introductions of influenza A virus to exhibition swine and study viral population dynamics. In 2013 alone, we identified 10 independent introductions of influenza A virus into Ohio and/or Indiana exhibition swine. Frequently, viruses from the same introduction were identified at multiple fairs within the region, providing evidence of rapid and widespread viral movement within the exhibition swine populations of the two states. While pigs moving from fair to fair to fair is possible in some locations, the concurrent detection of nearly identical strains at several fairs indicates that a common viral source was more likely. Importantly, we detected an association between the high number of human variant H3N2 (H3N2v) virus infections in 2012 and the widespread circulation of influenza A viruses of the same genotype in exhibition swine in Ohio fairs sampled that year. The extent of viral diversity observed in exhibition swine and the rapidity with which it disseminated across long distances indicate that novel strains of influenza A virus will continue to emerge and spread within exhibition swine populations, presenting an ongoing threat to humans. IMPORTANCE Understanding the underlying population dynamics of influenza A viruses in commercial and exhibition swine is central to assessing the risk for human infections with variant viruses, including H3N2v. We used viral genomic sequences from isolates collected from exhibition swine during 2009 to 2013 to understand

  3. Global migration of influenza A viruses in swine

    USDA-ARS?s Scientific Manuscript database

    The emergence of the 2009 A/H1N1 pandemic virus underscores the importance of understanding how influenza A viruses evolve in swine on a global scale. To reveal the frequency, patterns and drivers of the spread of swine influenza virus globally, we conducted the largest phylogenetic analysis of swin...

  4. Computer-aided assessment of pulmonary disease in novel swine-origin H1N1 influenza on CT

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Dwyer, Andrew J.; Summers, Ronald M.; Mollura, Daniel J.

    2011-03-01

    The 2009 pandemic is a global outbreak of novel H1N1 influenza. Radiologic images can be used to assess the presence and severity of pulmonary infection. We develop a computer-aided assessment system to analyze the CT images from Swine-Origin Influenza A virus (S-OIV) novel H1N1 cases. The technique is based on the analysis of lung texture patterns and classification using a support vector machine (SVM). Pixel-wise tissue classification is computed from the SVM value. The method was validated on four H1N1 cases and ten normal cases. We demonstrated that the technique can detect regions of pulmonary abnormality in novel H1N1 patients and differentiate these regions from visually normal lung (area under the ROC curve is 0.993). This technique can also be applied to differentiate regions infected by different pulmonary diseases.

  5. Insights from investigating the interactions of adamantane-based drugs with the M2 proton channel from the H1N1 swine virus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Jing-Fang; Wei, Dong-Qing, E-mail: dqwei@gordonlifescience.org; Gordon Life Science Institute, 13784 Torrey Del Mar Drive, San Diego, CA 92130

    The M2 proton channel is one of indispensable components for the influenza A virus that plays a vital role in its life cycle and hence is an important target for drug design against the virus. In view of this, the three-dimensional structure of the H1N1-M2 channel was developed based on the primary sequence taken from a patient recently infected by the H1N1 (swine flu) virus. With an explicit water-membrane environment, molecular docking studies were performed for amantadine and rimantadine, the two commercial drugs generally used to treat influenza A infection. It was found that their binding affinity to the H1N1-M2more » channel is significantly lower than that to the H5N1-M2 channel, fully consistent with the recent report that the H1N1 swine virus was resistant to the two drugs. The findings and the relevant analysis reported here might provide useful structural insights for developing effective drugs against the new swine flu virus.« less

  6. Insights from investigating the interactions of adamantane-based drugs with the M2 proton channel from the H1N1 swine virus.

    PubMed

    Wang, Jing-Fang; Wei, Dong-Qing; Chou, Kuo-Chen

    2009-10-16

    The M2 proton channel is one of indispensable components for the influenza A virus that plays a vital role in its life cycle and hence is an important target for drug design against the virus. In view of this, the three-dimensional structure of the H1N1-M2 channel was developed based on the primary sequence taken from a patient recently infected by the H1N1 (swine flu) virus. With an explicit water-membrane environment, molecular docking studies were performed for amantadine and rimantadine, the two commercial drugs generally used to treat influenza A infection. It was found that their binding affinity to the H1N1-M2 channel is significantly lower than that to the H5N1-M2 channel, fully consistent with the recent report that the H1N1 swine virus was resistant to the two drugs. The findings and the relevant analysis reported here might provide useful structural insights for developing effective drugs against the new swine flu virus.

  7. Serologic evidence of human influenza virus infections in swine populations, Cambodia.

    PubMed

    Rith, Sareth; Netrabukkana, Punnaporn; Sorn, San; Mumford, Elizabeth; Mey, Channa; Holl, Davun; Goutard, Flavie; Y, Bunthin; Fenwick, Stan; Robertson, Ian; Roger, François; Buchy, Philippe

    2013-05-01

    This study was conducted from 2006 to 2010 and investigated the seroprevalence of influenza A viruses in Cambodian pigs, including human H1N1, H3N2, 2009 pandemic H1N1 (A(H1N1)pdm09), and highly pathogenic avian H5N1 influenza A viruses. A total of 1147 sera obtained from pigs in Cambodia were tested by haemagglutination inhibition (HI) assays for antibody to human influenza A viruses along with both HI and microneutralization (MN) tests to assess immunological responses to H5N1 virus. The results were compared by year, age, and province. Antibodies against a human influenza A virus were detected in 14·9% of samples. A(H1N1)pdm09 virus were dominant over the study period (23·1%), followed by those to human H1N1 (17·3%) and H3N2 subtypes (9·9%). No pigs were serologically positive for avian H5 influenza viruses. The seroprevalence of human H1N1 and H3N2 influenza viruses peaked in 2008, while that of A(H1N1)pdm09 reached a peak in 2010. No significant differences in seroprevalence to human influenza subtypes were observed in different age groups. Cambodian pigs were exposed to human strains of influenza A viruses either prior to or during this study. The implications of these high prevalence rates imply human-to-swine influenza virus transmission in Cambodia. Although pigs are mostly raised in small non-commercial farms, our preliminary results provide evidence of sustained human influenza virus circulation in pig populations in Cambodia. © 2012 Blackwell Publishing Ltd.

  8. Serologic evidence of human influenza virus infections in swine populations, Cambodia

    PubMed Central

    Rith, Sareth; Netrabukkana, Punnaporn; Sorn, San; Mumford, Elizabeth; Mey, Channa; Holl, Davun; Goutard, Flavie; Y, Bunthin; Fenwick, Stan; Robertson, Ian; Roger, François; Buchy, Philippe

    2012-01-01

    Background  This study was conducted from 2006 to 2010 and investigated the seroprevalence of influenza A viruses in Cambodian pigs, including human H1N1, H3N2, 2009 pandemic H1N1 (A(H1N1)pdm09), and highly pathogenic avian H5N1 influenza A viruses. Methods  A total of 1147 sera obtained from pigs in Cambodia were tested by haemagglutination inhibition (HI) assays for antibody to human influenza A viruses along with both HI and microneutralization (MN) tests to assess immunological responses to H5N1 virus. The results were compared by year, age, and province. Results  Antibodies against a human influenza A virus were detected in 14·9% of samples. A(H1N1)pdm09 virus were dominant over the study period (23·1%), followed by those to human H1N1 (17·3%) and H3N2 subtypes (9·9%). No pigs were serologically positive for avian H5 influenza viruses. The seroprevalence of human H1N1 and H3N2 influenza viruses peaked in 2008, while that of A(H1N1)pdm09 reached a peak in 2010. No significant differences in seroprevalence to human influenza subtypes were observed in different age groups. Conclusions  Cambodian pigs were exposed to human strains of influenza A viruses either prior to or during this study. The implications of these high prevalence rates imply human‐to‐swine influenza virus transmission in Cambodia. Although pigs are mostly raised in small non‐commercial farms, our preliminary results provide evidence of sustained human influenza virus circulation in pig populations in Cambodia. PMID:22642704

  9. Emergence of a novel swine-origin influenza A (H1N1) virus in humans.

    PubMed

    Dawood, Fatimah S; Jain, Seema; Finelli, Lyn; Shaw, Michael W; Lindstrom, Stephen; Garten, Rebecca J; Gubareva, Larisa V; Xu, Xiyan; Bridges, Carolyn B; Uyeki, Timothy M

    2009-06-18

    On April 15 and April 17, 2009, novel swine-origin influenza A (H1N1) virus (S-OIV) was identified in specimens obtained from two epidemiologically unlinked patients in the United States. The same strain of the virus was identified in Mexico, Canada, and elsewhere. We describe 642 confirmed cases of human S-OIV infection identified from the rapidly evolving U.S. outbreak. Enhanced surveillance was implemented in the United States for human infection with influenza A viruses that could not be subtyped. Specimens were sent to the Centers for Disease Control and Prevention for real-time reverse-transcriptase-polymerase-chain-reaction confirmatory testing for S-OIV. From April 15 through May 5, a total of 642 confirmed cases of S-OIV infection were identified in 41 states. The ages of patients ranged from 3 months to 81 years; 60% of patients were 18 years of age or younger. Of patients with available data, 18% had recently traveled to Mexico, and 16% were identified from school outbreaks of S-OIV infection. The most common presenting symptoms were fever (94% of patients), cough (92%), and sore throat (66%); 25% of patients had diarrhea, and 25% had vomiting. Of the 399 patients for whom hospitalization status was known, 36 (9%) required hospitalization. Of 22 hospitalized patients with available data, 12 had characteristics that conferred an increased risk of severe seasonal influenza, 11 had pneumonia, 8 required admission to an intensive care unit, 4 had respiratory failure, and 2 died. The S-OIV was determined to have a unique genome composition that had not been identified previously. A novel swine-origin influenza A virus was identified as the cause of outbreaks of febrile respiratory infection ranging from self-limited to severe illness. It is likely that the number of confirmed cases underestimates the number of cases that have occurred. 2009 Massachusetts Medical Society

  10. The global antigenic diversity of swine influenza A viruses

    PubMed Central

    Lewis, Nicola S; Russell, Colin A; Langat, Pinky; Anderson, Tavis K; Berger, Kathryn; Bielejec, Filip; Burke, David F; Dudas, Gytis; Fonville, Judith M; Fouchier, Ron AM; Kellam, Paul; Koel, Bjorn F; Lemey, Philippe; Nguyen, Tung; Nuansrichy, Bundit; Peiris, JS Malik; Saito, Takehiko; Simon, Gaelle; Skepner, Eugene; Takemae, Nobuhiro; Webby, Richard J; Van Reeth, Kristien; Brookes, Sharon M; Larsen, Lars; Watson, Simon J; Brown, Ian H; Vincent, Amy L

    2016-01-01

    Swine influenza presents a substantial disease burden for pig populations worldwide and poses a potential pandemic threat to humans. There is considerable diversity in both H1 and H3 influenza viruses circulating in swine due to the frequent introductions of viruses from humans and birds coupled with geographic segregation of global swine populations. Much of this diversity is characterized genetically but the antigenic diversity of these viruses is poorly understood. Critically, the antigenic diversity shapes the risk profile of swine influenza viruses in terms of their epizootic and pandemic potential. Here, using the most comprehensive set of swine influenza virus antigenic data compiled to date, we quantify the antigenic diversity of swine influenza viruses on a multi-continental scale. The substantial antigenic diversity of recently circulating viruses in different parts of the world adds complexity to the risk profiles for the movement of swine and the potential for swine-derived infections in humans. DOI: http://dx.doi.org/10.7554/eLife.12217.001 PMID:27113719

  11. Vaccination with Killed but Metabolically Active E. coli Over-expressing Hemagglutinin Elicits Neutralizing Antibodies to H1N1 Swine Origin Influenza A Virus

    PubMed Central

    Liu, Pei-Feng; Wang, Yanhan; Liu, Yu-Tsueng; Huang, Chun-Ming

    2017-01-01

    There is a need for a fast and simple method for vaccine production to keep up with the pace of a rapidly spreading virus in the early phases of the influenza pandemic. The use of whole viruses produced in chicken eggs or recombinant antigens purified from various expression systems has presented considerable challenges, especially with lengthy processing times. Here, we use the killed but metabolically active (KBMA) Escherichia coli (E. coli) to harbor the hemagglutinin (HA) of swine origin influenza A (H1N1) virus (S-OIV) San Diego/01/09 (SD/H1N1-S-OIV). Intranasal vaccination of mice with KBMA E. coli SD/H1N1-S-OIV HA without adding exogenous adjuvants provoked detectable neutralizing antibodies against the virus-induced hemagglutination within three weeks. Boosting vaccination enhanced the titers of neutralizing antibodies, which can decrease viral infectivity in Madin-Darby canine kidney (MDCK) cells. The antibodies were found to specifically neutralize the SD/H1N1-S-OIV-, but not seasonal influenza viruses (H1N1 and H3N2), -induced hemagglutination. The use of KBMA E. coli as an egg-free system to produce anti-influenza vaccines makes unnecessary the rigorous purification of an antigen prior to immunization, providing an alternative modality to combat influenza virus in future outbreaks. PMID:28492063

  12. Integrative analysis of differentially expressed microRNAs of pulmonary alveolar macrophages from piglets during H1N1 swine influenza A virus infection

    PubMed Central

    Jiang, Pengfei; Zhou, Na; Chen, Xinyu; Zhao, Xing; Li, Dengyun; Wang, Fen; Bi, Lijun; Zhang, Deli

    2015-01-01

    H1N1 swine influenza A virus (H1N1 SwIV) is one key subtype of influenza viruses with pandemic potential. MicroRNAs (miRNAs) are endogenous small RNA molecules that regulate gene expression. MiRNAs relevant with H1N1 SwIV have rarely been reported. To understand the biological functions of miRNAs during H1N1 SwIV infection, this study profiled differentially expressed (DE) miRNAs in pulmonary alveolar macrophages from piglets during the H1N1 SwIV infection using a deep sequencing approach, which was validated by quantitative real-time PCR. Compared to control group, 70 and 16 DE miRNAs were respectively identified on post-infection day (PID) 4 and PID 7. 56 DE miRNAs were identified between PID 4 and PID 7. Our results suggest that most host miRNAs are down-regulated to defend the H1N1 SwIV infection during the acute phase of swine influenza whereas their expression levels gradually return to normal during the recovery phase to avoid the occurrence of too severe porcine lung damage. In addition, targets of DE miRNAs were also obtained, for which bioinformatics analyses were performed. Our results would be useful for investigating the functions and regulatory mechanisms of miRNAs in human influenza because pig serves as an excellent animal model to study the pathogenesis of human influenza. PMID:25639204

  13. Higher titers of some H5N1 and recent human H1N1 and H3N2 influenza viruses in Mv1 Lu vs. MDCK cells

    PubMed Central

    2011-01-01

    Background The infectivity of influenza A viruses can differ among the various primary cells and continuous cell lines used for such measurements. Over many years, we observed that all things equal, the cytopathic effects caused by influenza A subtype H1N1, H3N2, and H5N1 viruses were often detected earlier in a mink lung epithelial cell line (Mv1 Lu) than in MDCK cells. We asked whether virus yields as measured by the 50% tissue culture infectious dose and plaque forming titer also differed in MDCK and Mv1 Lu cells infected by the same influenza virus subtypes. Results The 50% tissue culture infectious dose and plaque forming titer of many influenza A subtype H1N1, H3N2, and H5N1 viruses was higher in Mv1 Lu than in MDCK cells. Conclusions The yields of influenza subtype H1N1, H3N2, and H5N1 viruses can be higher in Mv1 Lu cells than in MDCK cells. PMID:21314955

  14. Swine Outbreak of Pandemic Influenza A Virus on a Canadian Research Farm Supports Human-to-Swine Transmission

    PubMed Central

    Keenliside, Julia; Wilkinson, Craig; Webby, Richard; Lu, Patricia; Sorensen, Ole; Fonseca, Kevin; Barman, Subrata; Rubrum, Adam; Stigger, Evelyn; Marrie, Thomas J.; Marshall, Frank; Spady, Donald W.; Hu, Jia; Loeb, Mark; Russell, Margaret L.; Babiuk, Lorne A.

    2011-01-01

    Background. Swine outbreaks of pandemic influenza A (pH1N1) suggest human introduction of the virus into herds. This study investigates a pH1N1 outbreak occurring on a swine research farm with 37 humans and 1300 swine in Alberta, Canada, from 12 June through 4 July 2009. Methods. The staff was surveyed about symptoms, vaccinations, and livestock exposures. Clinical findings were recorded, and viral testing and molecular characterization of isolates from humans and swine were performed. Human serological testing and performance of the human influenza-like illness (ILI) case definition were also studied. Results. Humans were infected before swine. Seven of 37 humans developed ILI, and 2 (including the index case) were positive for pH1N1 by reverse-transcriptase polymerase chain reaction (RT-PCR). Swine were positive for pH1N1 by RT-PCR 6 days after contact with the human index case and developed symptoms within 24 h of their positive viral test results. Molecular characterization of the entire viral genomes from both species showed minor nucleotide heterogeneity, with 1 amino acid change each in the hemagglutinin and nucleoprotein genes. Sixty-seven percent of humans with positive serological test results and 94% of swine with positive swab specimens had few or no symptoms. Compared with serological testing, the human ILI case definition had a specificity of 100% and sensitivity of 33.3%. The only factor associated with seropositivity was working in the swine nursery. Conclusions. Epidemiologic data support human-to-swine transmission, and molecular characterization confirms that virtually identical viruses infected humans and swine in this outbreak. Both species had mild illness and recovered without sequelae. PMID:21148514

  15. Impact of influenza in the post-pandemic phase: Clinical features in hospitalized patients with influenza A (H1N1) pdm09 and H3N2 viruses, during 2013 in Santa Fe, Argentina.

    PubMed

    Kusznierz, Gabriela; Carolina, Cudós; Manuel, Rudi Juan; Sergio, Lejona; Lucila, Ortellao; Julio, Befani; Mirta, Villani; Pedro, Morana; Graciana, Morera; Andrea, Uboldi; Elsa, Zerbini

    2017-07-01

    It is important to characterize the clinical and epidemiological pattern of the influenza A (H1N1) pdm09 virus and compare it with influenza A (H3N2) virus, as surveyed in just a few studies, in order to contribute to the implementation and strengthening of influenza control and prevention strategies. The aims in this study were to describe influenza clinical and epidemiological characteristics in hospitalized patients, caused by influenza A (H1N1)pdm09 and influenza A (H3N2) viruses during 2013, in Santa Fe, Argentina. A retrospective study was conducted over 2013 among hospitalized patients with laboratory-confirmed influenza diagnosis. In contrast to patients with influenza A (H3N2) (20.5%), a higher proportion of hospitalizations associated with influenza H1N1pdm were reported among adults aged 35-65 years (42.8%). Of all patients, 73.6% had an underlying medical condition. Hospitalized patients with H1N1pdm were subject to 2.6 (95%CI, 1.0-6.8) times higher risk of severity, than those hospitalized with influenza A (H3N2). This results demonstrate the impact in the post-pandemic era of H1N1pdm virus, with increased risk of severe disease, in relation to H3N2 virus, both viruses co-circulating during 2013. © 2017 Wiley Periodicals, Inc.

  16. Enhanced genetic characterization of influenza A(H3N2) viruses and vaccine effectiveness by genetic group, 2014–2015

    PubMed Central

    Flannery, Brendan; Zimmerman, Richard K.; Gubareva, Larisa V.; Garten, Rebecca J.; Chung, Jessie R.; Nowalk, Mary Patricia; Jackson, Michael L.; Jackson, Lisa A.; Monto, Arnold S.; Ohmit, Suzanne E.; Belongia, Edward A.; McLean, Huong Q.; Gaglani, Manjusha; Piedra, Pedro A.; Mishin, Vasiliy P.; Chesnokov, Anton P.; Spencer, Sarah; Thaker, Swathi N.; Barnes, John R.; Foust, Angie; Sessions, Wendy; Xu, Xiyan; Katz, Jacqueline; Fry, Alicia M.

    2018-01-01

    Background During the 2014–15 US influenza season, expanded genetic characterization of circulating influenza A(H3N2) viruses was used to assess the impact of genetic variability of influenza A(H3N2) viruses on influenza vaccine effectiveness (VE). Methods A novel pyrosequencing assay was used to determine genetic group based on hemagglutinin (HA) gene sequences of influenza A(H3N2) viruses from patients enrolled US Flu Vaccine Effectiveness network sites. Vaccine effectiveness was estimated using a test-negative design comparing vaccination among patients infected with influenza A(H3N2) viruses and uninfected patients. Results Among 9710 enrollees, 1868 (19%) tested positive for influenza A(H3N2); genetic characterization of 1397 viruses showed 1134 (81%) belonged to one HA genetic group (3C.2a) of antigenically drifted H3N2 viruses. Effectiveness of 2014–15 influenza vaccination varied by A(H3N2) genetic group from 1% (95% confidence interval [CI], −14% to 14%) against illness caused by antigenically drifted A(H3N2) group 3C.2a viruses versus 44% (95% CI, 16% to 63%) against illness caused by vaccine-like A(H3N2) group 3C.3b viruses. Conclusion Effectiveness of 2014–15 influenza vaccination varied by genetic group of influenza A(H3N2) virus. Changes in hemagglutinin genes related to antigenic drift were associated with reduced vaccine effectiveness. PMID:27190176

  17. Evidence of infection with avian, human, and swine influenza viruses in pigs in Cairo, Egypt.

    PubMed

    Gomaa, Mokhtar R; Kandeil, Ahmed; El-Shesheny, Rabeh; Shehata, Mahmoud M; McKenzie, Pamela P; Webby, Richard J; Ali, Mohamed A; Kayali, Ghazi

    2018-02-01

    The majority of the Egyptian swine population was culled in the aftermath of the 2009 H1N1 pandemic, but small-scale growing remains. We sampled pigs from piggeries and an abattoir in Cairo. We found virological evidence of infection with avian H9N2 and H5N1 viruses as well as human pandemic H1N1 influenza virus. Serological evidence suggested previous exposure to avian H5N1 and H9N2, human pandemic H1N1, and swine avian-like and human-like viruses. This raises concern about potential reassortment of influenza viruses in pigs and highlights the need for better control and prevention of influenza virus infection in pigs.

  18. Replication Capacity of Avian Influenza A(H9N2) Virus in Pet Birds and Mammals, Bangladesh.

    PubMed

    Lenny, Brian J; Shanmuganatham, Karthik; Sonnberg, Stephanie; Feeroz, Mohammed M; Alam, S M Rabiul; Hasan, M Kamrul; Jones-Engel, Lisa; McKenzie, Pamela; Krauss, Scott; Webster, Robert G; Jones, Jeremy C

    2015-12-01

    Avian influenza A(H9N2) is an agricultural and public health threat. We characterized an H9N2 virus from a pet market in Bangladesh and demonstrated replication in samples from pet birds, swine tissues, human airway and ocular cells, and ferrets. Results implicated pet birds in the potential dissemination and zoonotic transmission of this virus.

  19. Experimental infection of clade 1.1.2 (H5N1), clade 2.3.2.1c (H5N1) and clade 2.3.4.4 (H5N6) highly pathogenic avian influenza viruses in dogs.

    PubMed

    Lyoo, K S; Na, W; Phan, L V; Yoon, S W; Yeom, M; Song, D; Jeong, D G

    2017-12-01

    Since the emergence of highly pathogenic avian influenza (HPAI) H5N1 in Asia, the haemagglutinin (HA) gene of this virus lineage has continued to evolve in avian populations, and H5N1 lineage viruses now circulate concurrently worldwide. Dogs may act as an intermediate host, increasing the potential for zoonotic transmission of influenza viruses. Virus transmission and pathologic changes in HPAI clade 1.1.2 (H5N1)-, 2.3.2.1c (H5N1)- and 2.3.4.4 (H5N6)-infected dogs were investigated. Mild respiratory signs and antibody response were shown in dogs intranasally infected with the viruses. Lung histopathology showed lesions that were associated with moderate interstitial pneumonia in the infected dogs. In this study, HPAI H5N6 virus replication in dogs was demonstrated for the first time. Dogs have been suspected as a "mixing vessel" for reassortments between avian and human influenza viruses to occur. The replication of these three subtypes of the H5 lineage of HPAI viruses in dogs suggests that dogs could serve as intermediate hosts for avian-human influenza virus reassortment if they are also co-infected with human influenza viruses. © 2017 Blackwell Verlag GmbH.

  20. Heterologous Humoral Response against H5N1, H7N3, and H9N2 Avian Influenza Viruses after Seasonal Vaccination in a European Elderly Population

    PubMed Central

    Sanz, Ivan; Rojo, Silvia; Tamames, Sonia; Eiros, José María; Ortiz de Lejarazu, Raúl

    2017-01-01

    Avian influenza viruses are currently one of the main threats to human health in the world. Although there are some screening reports of antibodies against these viruses in humans from Western countries, most of these types of studies are conducted in poultry and market workers of Asian populations. The presence of antibodies against avian influenza viruses was evaluated in an elderly European population. An experimental study was conducted, including pre- and post-vaccine serum samples obtained from 174 elderly people vaccinated with seasonal influenza vaccines of 2006–2007, 2008–2009, 2009–2010, and 2010–2011 Northern Hemisphere vaccine campaigns. The presence of antibodies against A/H5N1, A/H7N3, and A/H9N2 avian influenza viruses were tested by using haemaglutination inhibition assays. Globally, heterotypic antibodies were found before vaccination in 2.9% of individuals against A/H5N1, 1.2% against A/H7N3, and 25.9% against A/H9N2. These pre-vaccination antibodies were present at titers ≥1/40 in 1.1% of individuals against A/H5N1, in 1.1% against H7N3, and in 0.6% against the A/H9N2 subtype. One 76 year-old male showed pre-vaccine antibodies (Abs) against those three avian influenza viruses, and another three individuals presented Abs against two different viruses. Seasonal influenza vaccination induced a significant number of heterotypic seroconversions against A/H5N1 (14.4%) and A/H9N2 (10.9%) viruses, but only one seroconversion was observed against the A/H7N3 subtype. After vaccination, four individuals showed Abs titers ≥1/40 against those three avian viruses, and 55 individuals against both A/H5N1 and A/H9N2. Seasonal vaccination is able to induce some weak heterotypic responses to viruses of avian origin in elderly individuals with no previous exposure to them. However, this response did not accomplish the European Medicament Agency criteria for influenza vaccine efficacy. The results of this study show that seasonal vaccines induce a broad

  1. Genetic analysis and antigenic characterization of swine origin influenza viruses isolated from humans in the United States, 1990-2010.

    PubMed

    Shu, Bo; Garten, Rebecca; Emery, Shannon; Balish, Amanda; Cooper, Lynn; Sessions, Wendy; Deyde, Varough; Smith, Catherine; Berman, LaShondra; Klimov, Alexander; Lindstrom, Stephen; Xu, Xiyan

    2012-01-05

    Swine influenza viruses (SIV) have been recognized as important pathogens for pigs and occasional human infections with swine origin influenza viruses (SOIV) have been reported. Between 1990 and 2010, a total of twenty seven human cases of SOIV infections have been identified in the United States. Six viruses isolated from 1990 to 1995 were recognized as classical SOIV (cSOIV) A(H1N1). After 1998, twenty-one SOIV recovered from human cases were characterized as triple reassortant (tr_SOIV) inheriting genes from classical swine, avian and human influenza viruses. Of those twenty-one tr_SOIV, thirteen were of A(H1N1), one of A(H1N2), and seven of A(H3N2) subtype. SOIV characterized were antigenically and genetically closely related to the subtypes of influenza viruses circulating in pigs but distinct from contemporary influenza viruses circulating in humans. The diversity of subtypes and genetic lineages in SOIV cases highlights the importance of continued surveillance at the animal-human interface. Copyright © 2011. Published by Elsevier Inc.

  2. THE EFFECT OF HEMOPHILUS INFLUENZAE SUIS VACCINES ON SWINE INFLUENZA

    PubMed Central

    Shope, Richard E.

    1937-01-01

    Either living or heat-killed H. influenzae suis vaccines, given intramuscularly to swine, elicit an immune response capable of modifying the course of a later swine influenza infection. The protection afforded is only partial and is in no way comparable to the complete immunity afforded by swine influenza virus vaccines. PMID:19870654

  3. Phylogeography of Influenza A(H3N2) Virus in Peru, 2010-2012.

    PubMed

    Pollett, Simon; Nelson, Martha I; Kasper, Matthew; Tinoco, Yeny; Simons, Mark; Romero, Candice; Silva, Marita; Lin, Xudong; Halpin, Rebecca A; Fedorova, Nadia; Stockwell, Timothy B; Wentworth, David; Holmes, Edward C; Bausch, Daniel G

    2015-08-01

    It remains unclear whether lineages of influenza A(H3N2) virus can persist in the tropics and seed temperate areas. We used viral gene sequence data sampled from Peru to test this source-sink model for a Latin American country. Viruses were obtained during 2010-2012 from influenza surveillance cohorts in Cusco, Tumbes, Puerto Maldonado, and Lima. Specimens positive for influenza A(H3N2) virus were randomly selected and underwent hemagglutinin sequencing and phylogeographic analyses. Analysis of 389 hemagglutinin sequences from Peru and 2,192 global sequences demonstrated interseasonal extinction of Peruvian lineages. Extensive mixing occurred with global clades, but some spatial structure was observed at all sites; this structure was weakest in Lima and Puerto Maldonado, indicating that these locations may experience greater viral traffic. The broad diversity and co-circulation of many simultaneous lineages of H3N2 virus in Peru suggests that this country should not be overlooked as a potential source for novel pandemic strains.

  4. Combining magnetic nanoparticle with biotinylated nanobodies for rapid and sensitive detection of influenza H3N2

    PubMed Central

    2014-01-01

    Our objective is to develop a rapid and sensitive assay based on magnetic beads to detect the concentration of influenza H3N2. The possibility of using variable domain heavy-chain antibodies (nanobody) as diagnostic tools for influenza H3N2 was investigated. A healthy camel was immunized with inactivated influenza H3N2. A nanobody library of 8 × 108 clones was constructed and phage displayed. After three successive biopanning steps, H3N2-specific nanobodies were successfully isolated, expressed in Escherichia coli, and purified. Sequence analysis of the nanobodies revealed that we possessed four classes of nanobodies against H3N2. Two nanobodies were further used to prepare our rapid diagnostic kit. Biotinylated nanobody was effectively immobilized onto the surface of streptavidin magnetic beads. The modified magnetic beads with nanobody capture specifically influenza H3N2 and can still be recognized by nanobodies conjugated to horseradish peroxidase (HRP) conjugates. Under optimized conditions, the present immunoassay exhibited a relatively high sensitive detection with a limit of 50 ng/mL. In conclusion, by combining magnetic beads with specific nanobodies, this assay provides a promising influenza detection assay to develop a potential rapid, sensitive, and low-cost diagnostic tool to screen for influenza infections. PMID:25328501

  5. Combining magnetic nanoparticle with biotinylated nanobodies for rapid and sensitive detection of influenza H3N2

    NASA Astrophysics Data System (ADS)

    Zhu, Min; Hu, Yonghong; Li, Guirong; Ou, Weijun; Mao, Panyong; Xin, Shaojie; Wan, Yakun

    2014-09-01

    Our objective is to develop a rapid and sensitive assay based on magnetic beads to detect the concentration of influenza H3N2. The possibility of using variable domain heavy-chain antibodies (nanobody) as diagnostic tools for influenza H3N2 was investigated. A healthy camel was immunized with inactivated influenza H3N2. A nanobody library of 8 × 108 clones was constructed and phage displayed. After three successive biopanning steps, H3N2-specific nanobodies were successfully isolated, expressed in Escherichia coli, and purified. Sequence analysis of the nanobodies revealed that we possessed four classes of nanobodies against H3N2. Two nanobodies were further used to prepare our rapid diagnostic kit. Biotinylated nanobody was effectively immobilized onto the surface of streptavidin magnetic beads. The modified magnetic beads with nanobody capture specifically influenza H3N2 and can still be recognized by nanobodies conjugated to horseradish peroxidase (HRP) conjugates. Under optimized conditions, the present immunoassay exhibited a relatively high sensitive detection with a limit of 50 ng/mL. In conclusion, by combining magnetic beads with specific nanobodies, this assay provides a promising influenza detection assay to develop a potential rapid, sensitive, and low-cost diagnostic tool to screen for influenza infections.

  6. Human infections with influenza A(H3N2) variant virus in the United States, 2011-2012

    USDA-ARS?s Scientific Manuscript database

    BACKGROUND. During August 2011-April 2012, 13 human infections with influenza A(H3N2) variant (H3N2v) virus were identified in the United States; 8 occurred in the prior 2 years. This virus differs from previous variant influenza viruses in that it contains the matrix (M) gene from the Influenza A(H...

  7. Prevalence of antibodies to swine influenza viruses in humans with occupational exposure to pigs, Thuringia, Germany, 2008-2009.

    PubMed

    Krumbholz, Andi; Lange, Jeannette; Dürrwald, Ralf; Hoyer, Heike; Bengsch, Stefan; Wutzler, Peter; Zell, Roland

    2010-09-01

    The Eurasian lineages of swine influenza viruses are different genetically from classical swine H1N1 influenza viruses and comprise avian-like H1N1 and human-like H1N2 and H3N2 subtypes. Although sporadic isolation of such viruses from human specimens has been reported, the prevalence of human infections is not known. In the present study, the seroprevalence against Eurasian swine influenza viruses was investigated. Sera were collected in Thuringia, Germany, from December 2007 to April 2009. The study group comprised 118 professionals with occupational exposure to pigs (50 pig slaughterers/meat inspectors, 46 pig farmers, 22 veterinarians caring for pig herds). The control group included 118 age- and gender-matched blood donors from Thuringia. As a result, 18 sera of the study group were identified with raised hemagglutination-inhibition titers against a panel of nine swine influenza viruses (three strains/ subtype). For 17/18 sera this finding was confirmed in the neutralization assay. For 11/18 sera the raise of titers was significant, that is, a fourfold increase of hemagglutination-inhibition titers was observed. No gender-specific bias of the high titer sera was observed. Twelve sera of the control group showed increased hemagglutination-inhibition titers against swine influenza viruses. Hemagglutination-inhibition titers of 2/12 control sera were raised fourfold but did not exhibit a significant increase of neutralization titers. All increased hemagglutination-inhibition titers of the control group may be explained by cross-reactivity with seasonal influenza virus strains, as all these sera also reacted with human strains.

  8. Characterization of influenza a outbreaks in Minnesota swine herds and measures taken to reduce the risk of zoonotic transmission.

    PubMed

    Beaudoin, A; Johnson, S; Davies, P; Bender, J; Gramer, M

    2012-03-01

    Influenza A virus infections commonly cause respiratory disease in swine and can be transmitted between people and pigs, with potentially novel strains introduced into herds and spilling back into the human population. The goals of this study were to characterize influenza infections in Minnesota pigs and assess biosecurity measures used by swine workers. Veterinarians submitting influenza-positive swine samples to the University of Minnesota Veterinary Diagnostic Laboratory between October 2007 and April 2009 were surveyed regarding disease-related information and biosecurity procedures at each farm. Influenza-positive samples were submitted year-round, peaking in spring and fall. H1N1 was the most commonly detected subtype (56%), followed by H3N2 (14%) and H1N2 (12%). Most positive submissions were associated with illness in growing pigs (median age 8.8 weeks, IQR 5-15). Median morbidity and mortality were 25% (IQR 10-48) and 2% (IQR 0.5-3.5), respectively. Vaccination of sows and growing pigs was conducted at 71% and 7.9% of the swine farms, respectively. Specialized footwear was reported as the most common form of protective equipment used by workers. Employee vaccination for seasonal influenza was 19%. The sow vaccination rate in this study is consistent with national data, although growing pig vaccination is lower than the national average. Seasonal and age trends identified here may provide diagnostic guidance when growing pigs experience respiratory disease. Inconsistent use of protective equipment and employee vaccination at swine farms indicates the need for further discussion and research of approaches to minimize interspecies influenza transmission on swine farms. © 2011 Blackwell Verlag GmbH.

  9. Novel reassortant influenza viruses between pandemic (H1N1) 2009 and other influenza viruses pose a risk to public health.

    PubMed

    Kong, Weili; Wang, Feibing; Dong, Bin; Ou, Changbo; Meng, Demei; Liu, Jinhua; Fan, Zhen-Chuan

    2015-12-01

    Influenza A virus (IAV) is characterized by eight single-stranded, negative sense RNA segments, which allows for gene reassortment among different IAV subtypes when they co-infect a single host cell simultaneously. Genetic reassortment is an important way to favor the evolution of influenza virus. Novel reassortant virus may pose a pandemic among humans. In history, three human pandemic influenza viruses were caused by genetic reassortment between avian, human and swine influenza viruses. Since 2009, pandemic (H1N1) 2009 (pdm/09 H1N1) influenza virus composed of two swine influenza virus genes highlighted the genetic reassortment again. Due to wide host species and high transmission of the pdm/09 H1N1 influenza virus, many different avian, human or swine influenza virus subtypes may reassert with it to generate novel reassortant viruses, which may result in a next pandemic among humans. So, it is necessary to understand the potential threat of current reassortant viruses between the pdm/09 H1N1 and other influenza viruses to public health. This study summarized the status of the reassortant viruses between the pdm/09 H1N1 and other influenza viruses of different species origins in natural and experimental conditions. The aim of this summarization is to facilitate us to further understand the potential threats of novel reassortant influenza viruses to public health and to make effective prevention and control strategies for these pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Genomic analysis of influenza A virus from captive wild boars in Brazil reveals a human-like H1N2 influenza virus.

    PubMed

    Biondo, Natalha; Schaefer, Rejane; Gava, Danielle; Cantão, Mauricio E; Silveira, Simone; Mores, Marcos A Z; Ciacci-Zanella, Janice R; Barcellos, David E S N

    2014-01-10

    Influenza is a viral disease that affects human and several animal species. In Brazil, H1N1, H3N2 and 2009 pandemic H1N1 A(H1N1)pdm09 influenza A viruses (IAV) circulate in domestic swine herds. Wild boars are also susceptible to IAV infection but in Brazil until this moment there are no reports of IAV infection in wild boars or in captive wild boars populations. Herein the occurrence of IAV in captive wild boars with the presence of lung consolidation lesions during slaughter was investigated. Lung samples were screened by RT-PCR for IAV detection. IAV positive samples were further analyzed by quantitative real-time PCR (qRRT-PCR), virus isolation, genomic sequencing, histopathology and immunohistochemistry (IHC). Eleven out of 60 lungs (18.3%) were positive for IAV by RT-PCR and seven out of the eleven were also positive for A(H1N1)pdm09 by qRRT-PCR. Chronic diffuse bronchopneumonia was observed in all samples and IHC analysis was negative for influenza A antigen. Full genes segments of H1N2 IAV were sequenced using Illumina's genome analyzer platform (MiSeq). The genomic analysis revealed that the HA and NA genes clustered with IAVs of the human lineage and the six internal genes were derived from the H1N1pdm09 IAV. This is the first report of a reassortant human-like H1N2 influenza virus infection in captive wild boars in Brazil and indicates the need to monitor IAV evolution in Suidae populations. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Population dynamics of cocirculating swine influenza A viruses in the United States from 2009 to 2012.

    PubMed

    Anderson, Tavis K; Nelson, Martha I; Kitikoon, Pravina; Swenson, Sabrina L; Korslund, John A; Vincent, Amy L

    2013-12-01

    Understanding the ecology and evolution of influenza A viruses (IAV) in mammalian hosts is critical to reduce disease burden in production animals and lower zoonotic infection risk in humans. Recent advances in influenza surveillance in US swine populations allow for timely epidemiological, phylogenetic, and virological analyses that monitor emergence of novel viruses and assess changes in viral population dynamics. To better understand IAV in the North American swine population, we undertook a phylogenetic analysis of 1075 HA, 1049 NA, and 1040 M sequences of IAV isolated from US swine during 2009-2012 through voluntary and anonymous submissions to the US Department of Agriculture IAV swine surveillance system. Analyses revealed changes in population dynamics among multiple clades of A/H1N1, A/H3N2, and A/H1N2 cocirculating in US swine populations during 2009-2012. Viral isolates were categorized into one of seven genetically and antigenically distinct hemagglutinin lineages: H1α, H1β, H1γ, H1δ1, H2, H1pdm09, and H3 cluster IV. There was an increase in occurrence of H1δ1 in samples submitted, with a concurrent decrease in H1pdm09. H3 cluster IV exhibited increasing diversification, warranting a re-evaluation of phylogenetic nomenclature criteria. Although H3N2 represented 25% of identified viruses, this subtype was reported in increasing proportion of sequenced isolates since late 2011. Surveillance and reporting of IAV in US swine have increased since 2009, and we demonstrate a period of expanded viral diversity. These data may be used to inform intervention strategies of vaccine and diagnostic updates and changes in swine health management. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  12. The influence of experimental infection of gilts with swine H1N2 influenza A virus during the second month of gestation on the course of pregnancy, reproduction parameters and clinical status.

    PubMed

    Kwit, Krzysztof; Pomorska-Mól, Małgorzata; Markowska-Daniel, Iwona

    2014-06-04

    The course of swine influenza in pigs is reported to be similar to human influenza. Occasionally abortions and other reproduction disorders have been associated with influenza A virus (IAV) infection in pigs. Abortions may be a consequence of high fever, pro-inflammatory cytokines or transplacental transmission of the virus.The role of IAV in the complications observed during pregnancy has been scanty and the true importance of this agent as a cause of reproductive problems in swine is not known. The aim was to determine the possible involvement of swine H1N2 IAV strain on reproductive disorders in pregnant gilts under experimental conditions. The gestation length was from 113 to 116 days, no abortion or any other reproduction disorders were noted. A PCR assay confirms the presence of IAV in the nasal swabs taken from inoculated gilts between 1 and 5 dpi. In the nasal swabs from control gilts and newborn piglets, no IAV genetic material was found. No viral RNA was detected in samples of blood taken from gilts and piglets, placentas, lungs and tracheas taken from piglets euthanized after delivery. The significant decrease in the number and percentage of lymphocytes without leukopenia was observed at 4 dpi in inoculated gilts. The percentage of granulocytes increased significantly at 4 dpi in inoculated pigs. The concentration of IL-6, IL-10 and TNF-α were higher in inoculated gilts, while IL-4 and IFN-γ were not detected in the serum of any of animals. The serum concentrations of C-reactive protein remained stable during study, while haptoglobin concentrations increased significantly after inoculation. The results of the study indicate that infection of pregnant gilts with swine H1N2 IAV in the second month of pregnancy does not cause abortion and other reproduction disorders. No evidence for transplacental transmission of swine H1N2 IAV was found. However, due to subclinical course of influenza in the present experiment caution should be taken in extrapolating

  13. The influence of experimental infection of gilts with swine H1N2 influenza A virus during the second month of gestation on the course of pregnancy, reproduction parameters and clinical status

    PubMed Central

    2014-01-01

    Background The course of swine influenza in pigs is reported to be similar to human influenza. Occasionally abortions and other reproduction disorders have been associated with influenza A virus (IAV) infection in pigs. Abortions may be a consequence of high fever, pro-inflammatory cytokines or transplacental transmission of the virus. The role of IAV in the complications observed during pregnancy has been scanty and the true importance of this agent as a cause of reproductive problems in swine is not known. The aim was to determine the possible involvement of swine H1N2 IAV strain on reproductive disorders in pregnant gilts under experimental conditions. Results The gestation length was from 113 to 116 days, no abortion or any other reproduction disorders were noted. A PCR assay confirms the presence of IAV in the nasal swabs taken from inoculated gilts between 1 and 5 dpi. In the nasal swabs from control gilts and newborn piglets, no IAV genetic material was found. No viral RNA was detected in samples of blood taken from gilts and piglets, placentas, lungs and tracheas taken from piglets euthanized after delivery. The significant decrease in the number and percentage of lymphocytes without leukopenia was observed at 4 dpi in inoculated gilts. The percentage of granulocytes increased significantly at 4 dpi in inoculated pigs. The concentration of IL-6, IL-10 and TNF-α were higher in inoculated gilts, while IL-4 and IFN-γ were not detected in the serum of any of animals. The serum concentrations of C-reactive protein remained stable during study, while haptoglobin concentrations increased significantly after inoculation. Conclusions The results of the study indicate that infection of pregnant gilts with swine H1N2 IAV in the second month of pregnancy does not cause abortion and other reproduction disorders. No evidence for transplacental transmission of swine H1N2 IAV was found. However, due to subclinical course of influenza in the present experiment caution

  14. New reassortant and enzootic European swine influenza viruses transmit efficiently through direct contact in the ferret model.

    PubMed

    Fobian, Kristina; Fabrizio, Thomas P; Yoon, Sun-Woo; Hansen, Mette Sif; Webby, Richard J; Larsen, Lars E

    2015-07-01

    The reverse zoonotic events that introduced the 2009 pandemic influenza virus into pigs have drastically increased the diversity of swine influenza viruses in Europe. The pandemic potential of these novel reassortments is still unclear, necessitating enhanced surveillance of European pigs with additional focus on risk assessment of these new viruses. In this study, four European swine influenza viruses were assessed for their zoonotic potential. Two of the four viruses were enzootic viruses of subtype H1N2 (with avian-like H1) and H3N2, and two were new reassortants, one with avian-like H1 and human-like N2 and one with 2009 pandemic H1 and swine-like N2. All viruses replicated to high titres in nasal wash and nasal turbinate samples from inoculated ferrets and transmitted efficiently by direct contact. Only the H3N2 virus transmitted to naïve ferrets via the airborne route. Growth kinetics using a differentiated human bronchial epithelial cell line showed that all four viruses were able to replicate to high titres. Further, the viruses revealed preferential binding to the 2,6-α-silalylated glycans and investigation of the antiviral susceptibility of the viruses revealed that all were sensitive to neuraminidase inhibitors. These findings suggested that these viruses have the potential to infect humans and further underline the need for continued surveillance as well as biological characterization of new influenza A viruses.

  15. Surveillance of human influenza A(H3N2) virus from 1999 to 2009 in southern Italy.

    PubMed

    DE Donno, A; Idolo, A; Quattrocchi, M; Zizza, A; Gabutti, G; Romano, A; Grima, P; Donatelli, I; Guido, M

    2014-05-01

    The aim of this study was to evaluate the presence of influenza virus co-infections in humans and changes in the genetic variability of A(H3N2) virus strains in southern Italy from 1999 to 2009. A partial sequence of the haemagglutinin (HA) gene by human influenza H3N2 strains identified in oropharyngeal swabs from patients with influenza-like illness was analysed by DNA sequencing and a phylogenetic analysis was performed. During the seasons 1999-2000, 2002-2003, 2004-2005 and 2008-2009, the influenza viruses circulating belonged to subtype H3N2. However, A(H1N1) subtype virus and B type were respectively prevalent during the 2000-2001, 2006-2007, 2007-2008 and 2001-2002, 2003-2004, 2005-2006 seasons. The HA sequences appeared to be closely related to the sequence of the influenza A vaccine strain. Only the 2002-2003 season was characterized by co-circulation of two viral lineages: A/New York/55/01(H3N2)-like virus of the previous season and A/Fujian/411/02(H3N2)-like virus, a new H3 variant. In this study, over the decade analysed, no significant change was seen in the sequences of the HA gene of H3 viruses isolated.

  16. Pathogenicity and transmission of the novel A (H3N2v) influenza virus isolated from humans in experimentally inoculated pigs

    USDA-ARS?s Scientific Manuscript database

    Human cases with H3N2 (H3N2v) viruses closely related to swine H3N2 viruses were detected in 2011 and increased to >320 cases by the end of 2012. H3N2-TRIG was the H3N2 genotype endemically circulating in the U.S. swine population prior to the emergence of H1N1pdm09, and rH3N2p are novel H1N1pdm09/H...

  17. National surveillance for swine influenza virus in the United States, 2009-present

    USDA-ARS?s Scientific Manuscript database

    Background and Objectives. In April 2009, a National surveillance plan for swine influenza virus in swine was implemented in the United States. Initial focus of the surveillance was to detect the presence and distribution of viruses (especially the 2009 H1N1 pandemic influenza, A(H1N1)pdm09) that ar...

  18. Predominance of influenza A(H3N2) viruses during the 2016/2017 season in Bulgaria.

    PubMed

    Korsun, Neli; Angelova, Svetla; Trifonova, Ivelina; Tzotcheva, Iren; Mileva, Sirma; Voleva, Silvia; Georgieva, Irina; Perenovska, Penka

    2018-02-01

    Influenza viruses are characterised by high variability, which makes them able to cause annual epidemics. The aim of this study is to determine the antigenic and genetic characteristics of influenza viruses circulating in Bulgaria during the 2016/2017 season. The detection and typing/subtyping of influenza viruses were performed using real time RT-PCR. Results of antigenic characterisation, phylogenetic and amino acid sequence analyses of representative influenza strains are presented herein. The 2016/2017 season was characterised by an early start, an exclusive dominance of A(H3N2) viruses accounting for 93 % of total influenza virus detections, and a low circulation of A(H1N1)pdm09 (4.2 %) and type B (2.5 %) viruses. The analysed A(H3N2) viruses belonged to subclades 3C.2a (52 %) and 3C.2a1 (48 %); all studied A(H1N1)pdm09 and B/Victoria-lineage viruses belonged to subclades 6B.1 and 1A, respectively. The amino acid sequence analysis of 56 A(H3N2) isolates revealed the presence of substitutions in 18 positions in haemagglutinin (HA) as compared to the A/Hong Kong/4801/2014 vaccine virus, seven of which occurred in four antigenic sites, together with changes in 23 positions in neuraminidase (NA), and a number of substitutions in internal proteins PB2, PB1, PB1-F2, PA, NP and NS1. Despite the many amino acid substitutions, A(H3N2) viruses remained antigenically similar to the vaccine strain. Substitutions in HA and NA sequences of A(H1N1)pdm09 and B/Victoria-lineage strains were also identified, including in antigenic sites. The results of this study confirm the genetic variability of circulating influenza viruses, particularly A(H3N2), and the need for continued antigenic and molecular surveillance.

  19. Expanded Cocirculation of Stable Subtypes, Emerging Lineages, and New Sporadic Reassortants of Porcine Influenza Viruses in Swine Populations in Northwest Germany

    PubMed Central

    grosse Beilage, Elisabeth; Lange, Elke; Meiners, Carolin; Döhring, Stefanie; Pesch, Stefan; Noé, Thomas; Grund, Christian; Beer, Martin; Starick, Elke

    2013-01-01

    The emergence of the human 2009 pandemic H1N1 (H1N1pdm) virus from swine populations refocused public and scientific attention on swine as an important source of influenza A viruses bearing zoonotic potential. Widespread and year-round circulation of at least four stable lineages of porcine influenza viruses between 2009 and 2012 in a region of Germany with a high-density swine population is documented here. European avian influenza virus-derived H1N1 (H1N1av) viruses dominated the epidemiology, followed by human-derived subtypes H1N2 and H3N2. H1N1pdm viruses and, in particular, recently emerging reassortants between H1N1pdm and porcine HxN2 viruses (H1pdmN2) were detected in about 8% of cases. Further reassortants between these main lineages were diagnosed sporadically. Ongoing diversification both at the phylogenetic and at the antigenic level was evident for the H1N1av lineage and for some of its reassortants. The H1avN2 reassortant R1931/11 displayed conspicuously distinct genetic and antigenic features and was easily transmitted from pig to pig in an experimental infection. Continuing diverging evolution was also observed in the H1pdmN2 lineage. These viruses carry seven genome segments of the H1N1pdm virus, including a hemagglutinin gene that encodes a markedly antigenically altered protein. The zoonotic potential of this lineage remains to be determined. The results highlight the relevance of surveillance and control of porcine influenza virus infections. This is important for the health status of swine herds. In addition, a more exhaustive tracing of the formation, transmission, and spread of new reassortant influenza A viruses with unknown zoonotic potential is urgently required. PMID:23824819

  20. Phylogeography of Influenza A(H3N2) Virus in Peru, 2010–2012

    PubMed Central

    Nelson, Martha I.; Kasper, Matthew; Tinoco, Yeny; Simons, Mark; Romero, Candice; Silva, Marita; Lin, Xudong; Halpin, Rebecca A.; Fedorova, Nadia; Stockwell, Timothy B.; Wentworth, David; Holmes, Edward C.; Bausch, Daniel G.

    2015-01-01

    It remains unclear whether lineages of influenza A(H3N2) virus can persist in the tropics and seed temperate areas. We used viral gene sequence data sampled from Peru to test this source–sink model for a Latin American country. Viruses were obtained during 2010–2012 from influenza surveillance cohorts in Cusco, Tumbes, Puerto Maldonado, and Lima. Specimens positive for influenza A(H3N2) virus were randomly selected and underwent hemagglutinin sequencing and phylogeographic analyses. Analysis of 389 hemagglutinin sequences from Peru and 2,192 global sequences demonstrated interseasonal extinction of Peruvian lineages. Extensive mixing occurred with global clades, but some spatial structure was observed at all sites; this structure was weakest in Lima and Puerto Maldonado, indicating that these locations may experience greater viral traffic. The broad diversity and co-circulation of many simultaneous lineages of H3N2 virus in Peru suggests that this country should not be overlooked as a potential source for novel pandemic strains. PMID:26196599

  1. Analytical detection of influenza A(H3N2)v and other A variant viruses from the USA by rapid influenza diagnostic tests.

    PubMed

    Balish, Amanda; Garten, Rebecca; Klimov, Alexander; Villanueva, Julie

    2013-07-01

    The performance of rapid influenza diagnostic tests (RIDTs) that detect influenza viral nucleoprotein (NP) antigen has been reported to be variable. Recent human infections with variant influenza A viruses that are circulating in pigs prompted the investigation of the analytical reactivity of RIDTs with these variant viruses. To determine analytical reactivity of seven FDA-cleared RIDTs with influenza A variant viruses in comparison with the reactivity with recently circulating seasonal influenza A viruses. Tenfold serial dilutions of cell culture-grown seasonal and variant influenza A viruses were prepared and tested in duplicate with seven RIDTs. All RIDTs evaluated in this study detected the seasonal influenza A(H3N2) virus, although detection limits varied among assays. All but one examined RIDT identified the influenza A(H1N1)pdm09 virus. However, only four of seven RIDTs detected all influenza A(H3N2)v, A(H1N2)v, and A(H1N1)v viruses. Reduced sensitivity of RIDTs to variant influenza viruses may be due to amino acid differences between the NP proteins of seasonal viruses and the NP proteins from viruses circulating in pigs. Clinicians should be aware of the limitations of RIDTs to detect influenza A variant viruses. Specimens from patients with influenza-like illness in whom H3N2v is suspected should be sent to public health laboratories for additional diagnostic testing. Published 2012. This article is a US Government work and is in the public domain in the USA.

  2. Full-Genome Sequence of a Reassortant H1N2 Influenza A Virus Isolated from Pigs in Brazil.

    PubMed

    Schmidt, Candice; Cibulski, Samuel Paulo; Muterle Varela, Ana Paula; Mengue Scheffer, Camila; Wendlant, Adrieli; Quoos Mayer, Fabiana; Lopes de Almeida, Laura; Franco, Ana Cláudia; Roehe, Paulo Michel

    2014-12-18

    In this study, the full-genome sequence of a reassortant H1N2 swine influenza virus is reported. The isolate has the hemagglutinin (HA) and neuraminidase (NA) genes from human lineage (H1-δ cluster and N2), and the internal genes (polymerase basic 1 [PB1], polymerase basic 2 [PB2], polymerase acidic [PA], nucleoprotein [NP], matrix [M], and nonstructural [NS]) are derived from human 2009 pandemic H1N1 (H1N1pdm09) virus. Copyright © 2014 Schmidt et al.

  3. 2009 pandemic H1N1 influenza virus elicits similar clinical course but differential host transcriptional response in mouse, macaque, and swine infection models

    PubMed Central

    2012-01-01

    Background The 2009 pandemic H1N1 influenza virus emerged in swine and quickly became a major global health threat. In mouse, non human primate, and swine infection models, the pH1N1 virus efficiently replicates in the lung and induces pro-inflammatory host responses; however, whether similar or different cellular pathways were impacted by pH1N1 virus across independent infection models remains to be further defined. To address this we have performed a comparative transcriptomic analysis of acute phase responses to a single pH1N1 influenza virus, A/California/04/2009 (CA04), in the lung of mice, macaques and swine. Results Despite similarities in the clinical course, we observed differences in inflammatory molecules elicited, and the kinetics of their gene expression changes across all three species. We found genes associated with the retinoid X receptor (RXR) signaling pathway known to control pro-inflammatory and metabolic processes that were differentially regulated during infection in each species, though the heterodimeric RXR partner, pathway associated signaling molecules, and gene expression patterns varied among the three species. Conclusions By comparing transcriptional changes in the context of clinical and virological measures, we identified differences in the host transcriptional response to pH1N1 virus across independent models of acute infection. Antiviral resistance and the emergence of new influenza viruses have placed more focus on developing drugs that target the immune system. Underlying overt clinical disease are molecular events that suggest therapeutic targets identified in one host may not be appropriate in another. PMID:23153050

  4. Swine Influenza/Variant Influenza Viruses

    MedlinePlus

    ... Address What's this? Submit What's this? Submit Button Influenza Types Seasonal Avian Swine Variant Pandemic Other Information on Swine Influenza/Variant Influenza Virus Language: English (US) Español Recommend ...

  5. Outbreak of H3N2 influenza at a US military base in Djibouti during the H1N1 pandemic of 2009.

    PubMed

    Cosby, Michael T; Pimentel, Guillermo; Nevin, Remington L; Fouad Ahmed, Salwa; Klena, John D; Amir, Ehab; Younan, Mary; Browning, Robert; Sebeny, Peter J

    2013-01-01

    Influenza pandemics have significant operational impact on deployed military personnel working in areas throughout the world. The US Department of Defense global influenza-like illness (ILI) surveillance network serves an important role in establishing baseline trends and can be leveraged to respond to outbreaks of respiratory illness. We identified and characterized an operationally unique outbreak of H3N2 influenza at Camp Lemonnier, Djibouti occurring simultaneously with the H1N1 pandemic of 2009 [A(H1N1)pdm09]. Enhanced surveillance for ILI was conducted at Camp Lemonnier in response to local reports of a possible outbreak during the A(H1N1)pdm09 pandemic. Samples were collected from consenting patients presenting with ILI (utilizing a modified case definition) and who completed a case report form. Samples were cultured and analyzed using standard real-time reverse transcriptase PCR (rt-RT-PCR) methodology and sequenced genetic material was phylogenetically compared to other published strains. rt-RT-PCR and DNA sequencing revealed that 25 (78%) of the 32 clinical samples collected were seasonal H3N2 and only 2 (6%) were A(H1N1)pdm09 influenza. The highest incidence of H3N2 occurred during the month of May and 80% of these were active duty military personnel. Phylogenetic analysis revealed that sequenced H3N2 strains were genetically similar to 2009 strains from the United States of America, Australia, and South east Asia. This outbreak highlights challenges in the investigation of influenza among deployed military populations and corroborates the public health importance of maintaining surveillance systems for ILI that can be enhanced locally when needed.

  6. Molecular Epidemiology of Influenza A/H3N2 Viruses Circulating in Mexico from 2003 to 2012

    PubMed Central

    Escalera-Zamudio, Marina; Nelson, Martha I.; Cobián Güemes, Ana Georgina; López-Martínez, Irma; Cruz-Ortiz, Natividad; Iguala-Vidales, Miguel; García, Elvia Rodríguez; Barrera-Badillo, Gisela; Díaz-Quiñonez, Jose Alberto; López, Susana; Arias, Carlos F.; Isa, Pavel

    2014-01-01

    In this work, nineteen influenza A/H3N2 viruses isolated in Mexico between 2003 and 2012 were studied. Our findings show that different human A/H3N2 viral lineages co-circulate within a same season and can also persist locally in between different influenza seasons, increasing the chance for genetic reassortment events. A novel minor cluster was also identified, named here as Korea, that circulated worldwide during 2003. Frequently, phylogenetic characterization did not correlate with the determined antigenic identity, supporting the need for the use of molecular evolutionary tools additionally to antigenic data for the surveillance and characterization of viral diversity during each flu season. This work represents the first long-term molecular epidemiology study of influenza A/H3N2 viruses in Mexico based on the complete genomic sequences and contributes to the monitoring of evolutionary trends of A/H3N2 influenza viruses within North and Central America. PMID:25075517

  7. Detection of swine-origin influenza A (H1N1) viruses using a paired surface plasma waves biosensor

    NASA Astrophysics Data System (ADS)

    Su, Li-Chen; Chang, Ying-Feng; Li, Ying-Chang; Hsieh, Jo-Ping; Lee, Cheng-Chung; Chou, Chien

    2010-08-01

    In order to enhance the sensitivity of conventional rapid test technique for the detection of swine-origin influenza A (H1N1) viruses (S-OIVs), we used a paired surface plasma waves biosensor (PSPWB) based on SPR in conjunction with an optical heterodyne technique. Experimentally, PSPWB showed a 125-fold improvement at least in the S-OIV detection as compared to conventional enzyme linked immunosorbent assay. Moreover, the detection limit of the PSPWB for the S-OIV detection was enhanced 250-fold in buffer at least in comparison with that of conventional rapid influenza diagnostic test.

  8. Sus scrofa miR-204 and miR-4331 Negatively Regulate Swine H1N1/2009 Influenza A Virus Replication by Targeting Viral HA and NS, Respectively.

    PubMed

    Zhang, Shishuo; Wang, Ruifang; Su, Huijuan; Wang, Biaoxiong; Sizhu, Suolang; Lei, Zhixin; Jin, Meilin; Chen, Huanchun; Cao, Jiyue; Zhou, Hongbo

    2017-04-03

    The prevalence of swine pandemic H1N1/2009 influenza A virus (SIV-H1N1/2009) in pigs has the potential to generate novel reassortant viruses, posing a great threat to human health. Cellular microRNAs (miRNAs) have been proven as promising small molecules for regulating influenza A virus replication by directly targeting viral genomic RNA. In this study, we predicted potential Sus scrofa (ssc-, swine) miRNAs targeting the genomic RNA of SIV-H1N1/2009 by RegRNA 2.0, and identified ssc-miR-204 and ssc-miR-4331 to target viral HA and NS respectively through dual-luciferase reporter assays. The messenger RNA (mRNA) levels of viral HA and NS were significantly suppressed when newborn pig trachea (NPTr) cells respectively overexpressed ssc-miR-204 and ssc-miR-4331 and were infected with SIV-H1N1/2009, whereas the suppression effect could be restored when respectively decreasing endogenous ssc-miR-204 and ssc-miR-4331 with inhibitors. Because of the importance of viral HA and NS in the life cycle of influenza A virus, ssc-miR-204 and ssc-miR-4331 exhibited an inhibition effect on SIV-H1N1/2009 replication. The antiviral effect was sequence-specific of SIV-H1N1/2009, for the target sites in HA and NS of H5N1 or H9N2 influenza A virus were not conserved. Furthermore, SIV-H1N1/2009 infection reversely downregulated the expression of ssc-miR-204 and ssc-miR-4331, which might facilitate the virus replication in the host. In summary, this work will provide us some important clues for controlling the prevalence of SIV-H1N1/2009 in pig populations.

  9. Emergence of novel clade 2.3.4 influenza A (H5N1) virus subgroups in Yunnan Province, China.

    PubMed

    Hu, Tingsong; Song, Jianling; Zhang, Wendong; Zhao, Huanyun; Duan, Bofang; Liu, Qingliang; Zeng, Wei; Qiu, Wei; Chen, Gang; Zhang, Yingguo; Fan, Quanshui; Zhang, Fuqiang

    2015-07-01

    From December 2013 to March 2014, a major wave of highly pathogenic avian influenza outbreak occurred in poultry in Yunnan Province, China. We isolated and characterized eight highly pathogenic avian influenza A (H5N1) viruses from poultry. Full genome influenza sequences and analyses have been performed. Sequence analyses revealed that they belonged to clade 2.3.4 but did not fit within the three defined subclades. The isolated viruses were provisional subclade 2.3.4.4e. The provisional subclade 2.3.4.4e viruses with six internal genes from avian influenza A (H5N2) viruses in 2013 were the novel reassortant influenza A (H5N1) viruses which were associated with the outbreak of H5N1 occurred in egg chicken farms in Yunnan Province. The HA genes were similar to subtype H5 viruses isolated from January to March of 2014 in Asia including H5N6 and H5N8. The NA genes were most closely related to A/chicken/Vietnam/NCVD-KA423/2013 (H5N1) from the subclade 2.3.2. The HI assay demonstrated a lack of antigenic relatedness between clades 2.3.4.4e and 2.3.4.1 (RE-5 vaccine strain) or 2.3.2.2 (RE-6 vaccine strain). Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Association of swine influenza H1N1 pandemic virus (SIV-H1N1p) with porcine respiratory disease complex in sows from commercial pig farms in Colombia.

    PubMed

    Jiménez, Luisa Fernanda Mancipe; Ramírez Nieto, Gloria; Alfonso, Victor Vera; Correa, Jairo Jaime

    2014-08-01

    Porcine respiratory disease complex (PRDC) is a serious health problem that mainly affects growing and finishing pigs. PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney (MDCK) cells. Positive isolates, identified via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin (HA) protein led to grouping of strains into circulating viruses identified during the human outbreak of 2009, classified as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1N1p-negative and -positive farms, but higher levels were recorded for SIV-H1N1p-positive farms. Odds ratio (OR) and P values revealed statistically significant differences (p<0.05) in PRDC presentation in gilts and multiparous sows of farms positive for SIV-H1N1p. Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.

  11. Outbreak of H3N2 Influenza at a US Military Base in Djibouti during the H1N1 Pandemic of 2009

    PubMed Central

    Cosby, Michael T.; Pimentel, Guillermo; Nevin, Remington L.; Fouad Ahmed, Salwa; Klena, John D.; Amir, Ehab; Younan, Mary; Browning, Robert; Sebeny, Peter J.

    2013-01-01

    Background Influenza pandemics have significant operational impact on deployed military personnel working in areas throughout the world. The US Department of Defense global influenza-like illness (ILI) surveillance network serves an important role in establishing baseline trends and can be leveraged to respond to outbreaks of respiratory illness. Objective We identified and characterized an operationally unique outbreak of H3N2 influenza at Camp Lemonnier, Djibouti occurring simultaneously with the H1N1 pandemic of 2009 [A(H1N1)pdm09]. Methods Enhanced surveillance for ILI was conducted at Camp Lemonnier in response to local reports of a possible outbreak during the A(H1N1)pdm09 pandemic. Samples were collected from consenting patients presenting with ILI (utilizing a modified case definition) and who completed a case report form. Samples were cultured and analyzed using standard real-time reverse transcriptase PCR (rt-RT-PCR) methodology and sequenced genetic material was phylogenetically compared to other published strains. Results rt-RT-PCR and DNA sequencing revealed that 25 (78%) of the 32 clinical samples collected were seasonal H3N2 and only 2 (6%) were A(H1N1)pdm09 influenza. The highest incidence of H3N2 occurred during the month of May and 80% of these were active duty military personnel. Phylogenetic analysis revealed that sequenced H3N2 strains were genetically similar to 2009 strains from the United States of America, Australia, and South east Asia. Conclusions This outbreak highlights challenges in the investigation of influenza among deployed military populations and corroborates the public health importance of maintaining surveillance systems for ILI that can be enhanced locally when needed. PMID:24339995

  12. Expression Dynamics of Innate Immunity in Influenza Virus-Infected Swine

    PubMed Central

    Montoya, María; Foni, Emanuela; Solórzano, Alicia; Razzuoli, Elisabetta; Baratelli, Massimiliano; Bilato, Dania; Córdoba, Lorena; del Burgo, Maria Angeles Martín; Martinez, Jorge; Martinez-Orellana, Pamela; Chiapponi, Chiara; Perlin, David S.; del Real, Gustavo; Amadori, Massimo

    2017-01-01

    The current circulating swine influenza virus (IV) subtypes in Europe (H1N1, H1N2, and H3N2) are associated with clinical outbreaks of disease. However, we showed that pigs could be susceptible to other IV strains that are able to cross the species barrier. In this work, we extended our investigations into whether different IV strains able to cross the species barrier might give rise to different innate immune responses that could be associated with pathological lesions. For this purpose, we used the same samples collected in a previous study of ours, in which healthy pigs had been infected with a H3N2 Swine IV and four different H3N8 IV strains circulating in different animal species. Pigs had been clinically inspected and four subjects/group were sacrificed at 3, 6, and 21 days post infection. In the present study, all groups but mock exhibited antibody responses to IV nucleoprotein protein. Pulmonary lesions and high-titered viral replication were observed in pigs infected with the swine-adapted virus. Interestingly, pigs infected with avian and seal H3N8 strains also showed moderate lesions and viral replication, whereas equine and canine IVs did not cause overt pathological signs, and replication was barely detectable. Swine IV infection induced interferon (IFN)-alpha and interleukin-6 responses in bronchoalveolar fluids (BALF) at day 3 post infection, as opposed to the other non-swine-adapted virus strains. However, IFN-alpha responses to the swine-adapted virus were not associated with an increase of the local, constitutive expression of IFN-alpha genes. Remarkably, the Equine strain gave rise to a Serum Amyloid A response in BALF despite little if any replication. Each virus strain could be associated with expression of cytokine genes and/or proteins after infection. These responses were observed well beyond the period of virus replication, suggesting a prolonged homeostatic imbalance of the innate immune system. PMID:28484702

  13. Swine Influenza (Swine Flu) in Pigs

    MedlinePlus

    ... Address What's this? Submit What's this? Submit Button Influenza Types Seasonal Avian Swine Variant Pandemic Other Key Facts about Swine Influenza (Swine Flu) in Pigs Language: English (US) Español ...

  14. A Single-Amino-Acid Substitution at Position 225 in Hemagglutinin Alters the Transmissibility of Eurasian Avian-Like H1N1 Swine Influenza Virus in Guinea Pigs

    PubMed Central

    Wang, Zeng; Yang, Huanliang; Chen, Yan; Tao, Shiyu; Liu, Liling; Kong, Huihui; Ma, Shujie; Meng, Fei; Suzuki, Yasuo; Qiao, Chuanling

    2017-01-01

    ABSTRACT Efficient transmission from human to human is the prerequisite for an influenza virus to cause a pandemic; however, the molecular determinants of influenza virus transmission are still largely unknown. In this study, we explored the molecular basis for transmission of Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses by comparing two viruses that are genetically similar but differ in their transmissibility in guinea pigs: the A/swine/Guangxi/18/2011 virus (GX/18) is highly transmissible by respiratory droplet in guinea pigs, whereas the A/swine/Heilongjiang/27/2012 virus (HLJ/27) does not transmit in this animal model. We used reverse genetics to generate a series of reassortants and mutants in the GX/18 background and tested their transmissibility in guinea pigs. We found that a single-amino-acid substitution of glycine (G) for glutamic acid (E) at position 225 (E225G) in the HA1 protein completely abolished the respiratory droplet transmission of GX/18, whereas the substitution of E for G at the same position (G225E) in HA1 enabled HLJ/27 to transmit in guinea pigs. We investigated the underlying mechanism and found that viruses bearing 225E in HA1 replicated more rapidly than viruses bearing 225G due to differences in assembly and budding efficiencies. Our study indicates that the amino acid 225E in HA1 plays a key role in EAH1N1 swine influenza virus transmission and provides important information for evaluating the pandemic potential of field influenza virus strains. IMPORTANCE Efficient transmission among humans is a prerequisite for a novel influenza virus to cause a human pandemic. Transmissibility of influenza viruses is a polygenic trait, and understanding the genetic determinants for transmissibility will provide useful insights for evaluating the pandemic potential of influenza viruses in the field. Several amino acids in the hemagglutinin (HA) protein of influenza viruses have been shown to be important for transmissibility, usually by

  15. Genomewide analysis of reassortment and evolution of human influenza A(H3N2) viruses circulating between 1968 and 2011.

    PubMed

    Westgeest, Kim B; Russell, Colin A; Lin, Xudong; Spronken, Monique I J; Bestebroer, Theo M; Bahl, Justin; van Beek, Ruud; Skepner, Eugene; Halpin, Rebecca A; de Jong, Jan C; Rimmelzwaan, Guus F; Osterhaus, Albert D M E; Smith, Derek J; Wentworth, David E; Fouchier, Ron A M; de Graaf, Miranda

    2014-03-01

    Influenza A(H3N2) viruses became widespread in humans during the 1968 H3N2 virus pandemic and have been a major cause of influenza epidemics ever since. These viruses evolve continuously by reassortment and genomic evolution. Antigenic drift is the cause for the need to update influenza vaccines frequently. Using two data sets that span the entire period of circulation of human influenza A(H3N2) viruses, it was shown that influenza A(H3N2) virus evolution can be mapped to 13 antigenic clusters. Here we analyzed the full genomes of 286 influenza A(H3N2) viruses from these two data sets to investigate the genomic evolution and reassortment patterns. Numerous reassortment events were found, scattered over the entire period of virus circulation, but most prominently in viruses circulating between 1991 and 1998. Some of these reassortment events persisted over time, and one of these coincided with an antigenic cluster transition. Furthermore, selection pressures and nucleotide and amino acid substitution rates of all proteins were studied, including those of the recently discovered PB1-N40, PA-X, PA-N155, and PA-N182 proteins. Rates of nucleotide and amino acid substitutions were most pronounced for the hemagglutinin, neuraminidase, and PB1-F2 proteins. Selection pressures were highest in hemagglutinin, neuraminidase, matrix 1, and nonstructural protein 1. This study of genotype in relation to antigenic phenotype throughout the period of circulation of human influenza A(H3N2) viruses leads to a better understanding of the evolution of these viruses. Each winter, influenza virus infects approximately 5 to 15% of the world's population, resulting in significant morbidity and mortality. Influenza A(H3N2) viruses evolve continuously by reassortment and genomic evolution. This leads to changes in antigenic recognition (antigenic drift) which make it necessary to update vaccines against influenza A(H3N2) viruses frequently. In this study, the relationship of genetic evolution

  16. Reverse zoonosis of influenza to swine: new perspectives on the human-animal interface

    PubMed Central

    Nelson, Martha I.; Vincent, Amy L.

    2015-01-01

    The origins of the influenza A (H1N1) pandemic of 2009 in swine are unknown, highlighting gaps in our understanding of influenza A virus ecology and evolution. Here we review how recently strengthened influenza virus surveillance in pigs has revealed that influenza virus transmission from humans to swine is far more frequent than swine-to-human zoonosis, and is central in seeding swine globally with new viral diversity. The scale of global human-to-swine transmission represents the largest ‘reverse zoonosis’ of a pathogen documented to date. Overcoming the bias towards perceiving swine as sources of human viruses, rather than recipients, is key to understanding how the bidirectional nature of the human-animal interface produces influenza threats to both hosts. PMID:25564096

  17. Reverse zoonosis of influenza to swine: new perspectives on the human-animal interface.

    PubMed

    Nelson, Martha I; Vincent, Amy L

    2015-03-01

    The origins of the 2009 influenza A (H1N1) pandemic in swine are unknown, highlighting gaps in our understanding of influenza A virus (IAV) ecology and evolution. We review how recently strengthened influenza virus surveillance in pigs has revealed that influenza virus transmission from humans to swine is far more frequent than swine-to-human zoonosis, and is central in seeding swine globally with new viral diversity. The scale of global human-to-swine transmission represents the largest 'reverse zoonosis' of a pathogen documented to date. Overcoming the bias towards perceiving swine as sources of human viruses, rather than recipients, is key to understanding how the bidirectional nature of the human-animal interface produces influenza threats to both hosts. Published by Elsevier Ltd.

  18. The molecular determinants of antibody recognition and antigenic drift in the H3 hemagglutinin of swine influenza A virus

    USDA-ARS?s Scientific Manuscript database

    Influenza A virus (IAV) of the H3 subtype is an important pathogen that affects both humans and swine. The main intervention strategy for preventing infection is vaccination to induce neutralizing antibodies against the surface glycoprotein hemagglutinin (HA). However, due to antigenic drift, vaccin...

  19. In vivo prophylactic activity of QR-435 against H3N2 influenza virus infection.

    PubMed

    Oxford, John S; Lambkin, Robert; Guralnik, Mario; Rosenbloom, Richard A; Petteruti, Michael P; Digian, Kelly; LeFante, Carolyn

    2007-01-01

    Prophylaxis against influenza infection can take several forms, none of which is totally effective at preventing the spread of the disease. QR-435, an all-natural compound of green-tea extract and other agents, has been developed to protect against a range of viral infections, including the influenza subtype H3N2. Several different QR-435 formulations were tested against the two influenza A H3N2 viruses (A/Sydney/5/97 and A/Panama/2007/99) in the ferret model. Most experiments included negative (phosphate-buffered saline) and positive (oseltamivir 5 mg/kg, twice daily) controls. QR-435 and the control were administered 5 minutes after intranasal delivery of the virus as prophylaxis against infection resulting from exposure to infected but untreated ferrets and for prevention of transmission from infected and treated ferrets to untreated animals. Effects of QR-435 on seroconversion, virus shedding, and systemic sequelae of infection (weight loss, fever, reduced activity) were evaluated. QR-435 prevented transmission and provided prophylaxis against influenza virus H3N2. Prophylaxis with QR-435 was significantly more than with oseltamivir in these experiments. Optimal in vivo efficacy of QR-435 requires a horseradish concentration of at least 50% of that in the original formulation, and the benefits of this preparation appear to be dose dependent. QR-435 is effective for both prevention of H3N2 viral transmission and prophylaxis. These preclinical results warrant further evaluation of its prophylactic properties against avian influenza virus infection in humans.

  20. Measurement of Swine H1N1 Hemagglutinin Peptide binding with Piezoresistive Microcantilever Arrays

    DOE PAGES

    Bajwa, Navdeep K; Maldonado, Carlos J.; Thundat, Thomas George; ...

    2014-03-24

    The effective detection of Swine H1N1 Hemagglutinin peptide is crucial as it could be used as a positive control to screen for highly infectious flu strains such as Swine-Origin Influenza A (H1N1). Piezoresistive microcantilever arrays present a pathway towards highly sensitive and label-free detection of biomolecules by transducing the antigen-antibody binding into change in resistivity via induced surface stress variation. We also demonstrate a mechanical transduction of Swine H1N1 Hemagglutinin peptide binding and suggest the employed technique may offer a potential platform for detection of the H1N1 virus, which could be clinically used to diagnose and provide subsequent relief.

  1. Piezoresistive measurement of Swine H1N1 Hemagglutinin peptide binding with microcantilever arrays

    NASA Astrophysics Data System (ADS)

    Bajwa, N.; Maldonado, C. J.; Thundat, T.; Passian, A.

    2014-03-01

    Effective detection of Swine H1N1 Hemagglutinin peptide is crucial as it could be used as a positive control to screen for highly infectious flu strains such as Swine-Origin Influenza A (H1N1). Piezoresistive microcantilever arrays present a pathway towards highly sensitive and label-free detection of biomolecules by transducing the antigen-antibody binding into change in resistivity via induced surface stress variation. We demonstrate a mechanical transduction of Swine H1N1 Hemagglutinin peptide binding and suggest the employed technique may offer a potential platform for detection of the H1N1 virus, which could be clinically used to diagnose and provide subsequent relief.

  2. Measurement of Swine H1N1 Hemagglutinin Peptide binding with Piezoresistive Microcantilever Arrays

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bajwa, Navdeep K; Maldonado, Carlos J.; Thundat, Thomas George

    The effective detection of Swine H1N1 Hemagglutinin peptide is crucial as it could be used as a positive control to screen for highly infectious flu strains such as Swine-Origin Influenza A (H1N1). Piezoresistive microcantilever arrays present a pathway towards highly sensitive and label-free detection of biomolecules by transducing the antigen-antibody binding into change in resistivity via induced surface stress variation. We also demonstrate a mechanical transduction of Swine H1N1 Hemagglutinin peptide binding and suggest the employed technique may offer a potential platform for detection of the H1N1 virus, which could be clinically used to diagnose and provide subsequent relief.

  3. The Continuing Evolution of H5N1 and H9N2 Influenza Viruses in Bangladesh

    PubMed Central

    Marinova-Petkova, Atanaska; Shanmuganatham, Karthik; Feeroz, Mohammed M.; Jones-Engel, Lisa; Hassan, M. Kamrul; Akhtar, Sharmin; Turner, Jasmine; Walker, David; Seiler, Patrick; Franks, John; McKenzie, Pamela; Krauss, Scott; Webby, Richard J.; Webster, Robert G.

    2017-01-01

    Summary In 2011, avian influenza surveillance at the Bangladesh live bird markets (LBMs) showed complete replacement of the highly pathogenic avian influenza (HPAI) H5N1 virus of clade 2.2.2 (Qinghai-like H5N1 lineage) by the HPAI H5N1 clade 2.3.2.1. This clade, which continues to circulate in Bangladesh and neighboring countries, is an intra- and inter-clade reassortant; its HA, PB1, PA and NS genes come from subclade 2.3.2.1a; PB2 from subclade 2.3.2.1c; and NA, NP, and M from clade 2.3.4.2. The H9N2 influenza viruses co-circulating in the Bangladesh LBMs are also reassortants, possessing five genes (NS, M, NP, PA, and PB1) from a HPAI H7N3 virus previously isolated in Pakistan. Despite frequent co-infection of chickens and ducks, reassortment between these H5N1 and H9N2 viruses has been rare. However, all such reassortants detected in 2011 through 2013 have carried 7 genes from HPAI H5N1 clade 2.3.2.1a and the PB1 gene from the Bangladeshi H9N2 clade G1 Mideast, itself derived from HPAI H7N3 virus. Although, the live birds which we sampled in Bangladesh showed no clinical signs of morbidity, the emergence of this reassortant HPAI H5N1 lineage further complicates endemic circulation of H5N1 viruses in Bangladesh, posing a threat to both poultry and humans. PMID:27309046

  4. Burden of pediatric influenza A virus infection post swine-flu H1N1 pandemic in Egypt.

    PubMed

    Khattab, Adel; Shaheen, Malak; Kamel, Terez; El Faramay, Amel; El Rahman, Safaa Abd; Nabil, Dalia; Gouda, Mohamed

    2013-09-01

    To screen children with influenza like illness or with symptoms of acute respiratory tract infections for influenza A virus infection - post swine flu pandemic era - using rapid influenza diagnostic tests. During two years (2010 & 2011), 1 200 children with influenza like illness or acute respiratory tract infections (according to World Health Organization criteria) were recruited. Their ages ranged from 2-60 months. Nasopharyngeal aspirates specimens were collected from all children for rapid influenza A diagnostic test. Influenza A virus rapid test was positive in 47.5% of the children; the majority (89.6%) were presented with lower respiratory tract infections. Respiratory rate and temperature were significantly higher among positive rapid influenza test patients. Influenza A virus infection is still a major cause of respiratory tract infections in Egyptian children. It should be considered in all cases with cough and febrile episodes and influenza like symptoms even post swine flu pandemic. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  5. Interim estimates of the effectiveness of the influenza vaccine against A(H3N2) influenza in adults in South Korea, 2016-2017 season.

    PubMed

    Noh, Ji Yun; Lim, Sooyeon; Song, Joon Young; Choi, Won Suk; Jeong, Hye Won; Heo, Jung Yeon; Lee, Jacob; Seo, Yu Bin; Lee, Jin-Soo; Wie, Seong Heon; Kim, Young Keun; Park, Kyung Hwa; Jung, Sook-In; Kim, Shin Woo; Lee, Sun Hee; Lee, Han Sol; Yoon, Young Hoon; Cheong, Hee Jin; Kim, Woo Joo

    2017-01-01

    In the 2016-2017 season, the A(H3N2) influenza epidemic presented an unusual early peak pattern compared with past seasons in South Korea. The interim vaccine effectiveness (VE) of influenza vaccination in preventing laboratory-confirmed influenza was estimated using test-negative design through the tertiary hospital-based influenza surveillance system in South Korea. From 1 September, 2016 to 7 January, 2017, adjusted VE of influenza vaccination in preventing laboratory-confirmed A(H3N2) was -52.1% (95% confidence interval [CI], -147.2 to 6.4); -70.0% (95% CI, -212.0 to 7.4) in 19-64 years and 4.3% (95% CI, -137.8 to 61.5) in the elderly. Circulating A(H3N2) viruses belonged to the three phylogenetic subclades of 3C.2a, differently to A/Hong Kong/4801/2014, the current vaccine strain. Amino acid substitutions in hemagglutinin of circulating viruses seem to contribute to low VE. In conclusion, interim VE analysis presented that the protection of laboratory-confirmed influenza by seasonal influenza vaccination did not show the statistical significance in South Korea in the 2016-2017 influenza season.

  6. Genesis and genetic constellations of swine influenza viruses in Thailand.

    PubMed

    Poonsuk, Sukontip; Sangthong, Pradit; Petcharat, Nantawan; Lekcharoensuk, Porntippa

    2013-12-27

    Swine influenza virus (SIV) is one of the most important zoonotic agents and the origin of the most recent pandemic virus. Asia is considered to be the epicenter for genetic exchanging of influenza A viruses and Southeast Asia including Thailand serves as a reservoir to maintain the persistence of the viruses for seeding other regions. Therefore, searching for new reassortants in this area has been routinely required. Although SIVs in Thailand have been characterized, collective information regarding their genetic evolution and gene constellations is limited. In this study, whole genomes of 30 SIVs isolated during clinical target surveillance plus all available sequences of past and currently circulating Thai SIVs were genetically characterized based on their evolutionary relationships. All genetic pools of Thai SIVs are comprised of four lineages including classical swine (CS), Eurasian swine (EAs), Triple reassortants (TRIG) and Seasonal human (Shs). Out of 84 isolates, nine H1N1, six H3N2 and one H1N2 strains were identified. Gene constellations of SIVs in Thailand are highly complex resulting from multiple reassortments among concurrently circulating SIVs and temporally introduced foreign genes. Most strains contain gene segments from both EAs and CS lineages and appeared transiently. TRIG lineage has been recently introduced into Thai SIV gene pools. The existence of EAs and TRIG lineages in this region may increase rates of genetic exchange and diversity while Southeast Asia is a persistent reservoir for influenza A viruses. Continual monitoring of SIV evolution in this region is crucial in searching for the next potential pandemic viruses. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Efficacy of Live-Attenuated H9N2 Influenza Vaccine Candidates Containing NS1 Truncations against H9N2 Avian Influenza Viruses.

    PubMed

    Chen, Sujuan; Zhu, Yinbiao; Yang, Da; Yang, Yang; Shi, Shaohua; Qin, Tao; Peng, Daxin; Liu, Xiufan

    2017-01-01

    H9N2 avian influenza virus is a zoonotic agent with a broad host range that can contribute genetic information to H5 or H7N9 subtype viruses, which are significant threats to both humans and birds. Thus, there is a great need for a vaccine to control H9N2 avian influenza. Three mutant viruses of an H9N2 virus A/chicken/Taixing/10/2010 (rTX-NS1-73, rTX-NS1-100, and rTX-NS1-128) were constructed with different NS1 gene truncations and confirmed by western blot analysis. The genetic stability, pathogenicity, transmissibility, and host immune responses toward these mutants were evaluated. The mutant virus rTX-NS1-128 exhibited the most attenuated phenotype and lost transmissibility. The expression levels of interleukin 12 in the nasal and tracheal tissues from chickens immunized with rTX-NS1-128 were significantly upregulated on day 3 post-immunization and the IgA and IgG antibody levels were significantly increased on days 7, 14, and 21 post-immunization when compared to chickens that received an inactivated vaccine. rTX-NS1-128 also protected chickens from challenge by homologous and heterologous H9N2 avian influenza viruses. The results indicate that rTX-NS1-128 can be used as a potential live-attenuated vaccine against H9N2 avian influenza.

  8. A phylogeny-based global nomenclature system and automated annotation tool for H1 hemagglutinin genes from swine influenza A viruses

    USDA-ARS?s Scientific Manuscript database

    The H1 subtype of influenza A viruses (IAV) has been circulating in swine since the 1918 human influenza pandemic. Over time, and aided by further introductions from non-swine hosts, swine H1 have diversified into three genetic lineages. Due to limited global data, these H1 lineages were named based...

  9. Rapid clinical diagnosis of Legionnaires' disease during the "herald wave" of the swine influenza (H1N1) pandemic: the Legionnaires' disease triad.

    PubMed

    Cunha, Burke A; Mickail, Nardeen; Syed, Uzma; Strollo, Stephanie; Laguerre, Marianne

    2010-01-01

    simplified diagnostic swine influenza (H1N1) triad was developed for the rapid clinical diagnosis of probable H1N1 pneumonia, which also differentiated it from its mimics as well as from bacterial pneumonia, eg, Legionnaires' disease. During the "herald wave" of the H1N1 pandemic, we noticed an unexplained increase in Legionnaires' disease CAPs. Because clinical resources were stressed to the maximum during the pandemic, it was critically important to rapidly identify patients rapidly with Legionnaire's disease who did not require influenza precautions or oseltamivir, but who did require anti-Legionella antimicrobial therapy. Based on the Winthrop-University Hospital Infectious Disease Division's diagnostic weighted point score system for Legionnaires' disease (modified), key indicators were identified and became the basis for the diagnostic Legionnaires' disease triad. The diagnostic Legionnaires' disease triad was used to make a clinical diagnosis of Legionnaires' disease until the results of Legionella diagnostic tests were reported. The diagnostic Legionnaires' disease triad diagnosed Legionnaires' disease in hospitalized adults with CAPs with extrapulmonary findings (atypical CAP) and relative bradycardia, accompanied by any three (ie, a triad) of the following: otherwise unexplained relative lymphopenia, early/mildly elevated serum transaminases (SGOT/SGPT), highly increased ferritin levels (> or =2 x n), or hypophosphatemia. The diagnostic Legionnaires' disease triad provides clinicians with a rapid way to clinically diagnose Legionnaires' disease, pending Legionella test results. The accuracy of the diagnostic Legionnaires' disease triad was confirmed in our 9 cases of Legionnaires' disease by subsequent Legionella diagnostic testing. The diagnostic Legionnaires' disease triad is particularly useful in situations where a rapid clinical syndromic diagnosis is needed, ie, during an H1N1 pandemic. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Activation of Influenza A Viruses by Host Proteases from Swine Airway Epithelium

    PubMed Central

    Peitsch, Catharina; Klenk, Hans-Dieter; Garten, Wolfgang

    2014-01-01

    Pigs are important natural hosts of influenza A viruses, and due to their susceptibility to swine, avian, and human viruses, they may serve as intermediate hosts supporting adaptation and genetic reassortment. Cleavage of the influenza virus surface glycoprotein hemagglutinin (HA) by host cell proteases is essential for viral infectivity. Most influenza viruses, including human and swine viruses, are activated at a monobasic HA cleavage site, and we previously identified TMPRSS2 and HAT to be relevant proteases present in human airways. We investigated the proteolytic activation of influenza viruses in primary porcine tracheal and bronchial epithelial cells (PTEC and PBEC, respectively). Human H1N1 and H3N2 viruses replicated efficiently in PTECs and PBECs, and viruses containing cleaved HA were released from infected cells. Moreover, the cells supported the proteolytic activation of HA at the stage of entry. We found that swine proteases homologous to TMPRSS2 and HAT, designated swTMPRSS2 and swAT, respectively, were expressed in several parts of the porcine respiratory tract. Both proteases cloned from primary PBECs were shown to activate HA with a monobasic cleavage site upon coexpression and support multicycle replication of influenza viruses. swAT was predominantly localized at the plasma membrane, where it was present as an active protease that mediated activation of incoming virus. In contrast, swTMPRSS2 accumulated in the trans-Golgi network, suggesting that it cleaves HA in this compartment. In conclusion, our data show that HA activation in porcine airways may occur by similar proteases and at similar stages of the viral life cycle as in human airways. PMID:24155384

  11. Connecting the dots between swine influenza A virus surveillance and vaccines

    USDA-ARS?s Scientific Manuscript database

    Introduction Influenza A virus (IAV) infection was first recognized in the USA swine population following the 1918 Spanish flu pandemic in humans with the identification of an H1N1 virus that became known as the classical swine H1N1. In 1997-98, the incursion of the triple reassortant viruses with g...

  12. Vaccine-induced protection from egg production losses in commercial turkey breeder hens following experimental challenge with a triple-reassortant H3N2 avian influenza virus.

    PubMed

    Kapczynski, Darrell R; Gonder, Eric; Liljebjelke, Karen; Lippert, Ron; Petkov, Daniel; Tilley, Becky

    2009-03-01

    Infections of avian influenza virus (AIV) in turkey breeder hens can cause a decrease in both egg production and quality, resulting in significant production losses. In North Carolina in 2003, a triple-reassortant H3N2 AIV containing human, swine, and avian gene segments was isolated from turkey breeder hens (A/turkey/NC/16108/03). This viral subtype was subsequently isolated from both turkeys and swine in Ohio in 2004, and in Minnesota in 2005, and was responsible for significant losses in turkey production. The objective of this study was to determine if currently available commercial, inactivated avian influenza H3 subtype oil-emulsion vaccines would protect laying turkey hens from egg production losses following challenge with the 2003 H3N2 field virus isolate from North Carolina. Laying turkey hens were vaccinated in the field with two injections of either a commercial monovalent (A/duck/Minnesota/79/79 [H3N4]) or autogenous bivalent (A/turkey/North Carolina/05 (H3N2)-A/turkey/North Carolina/88 [H1N1]) vaccine, at 26 and 30 wk of age, and subsequently challenged under BSL 3-Ag conditions at 32 wk of age. Vaccine-induced efficacy was determined as protection from a 50% decrease in egg production and from a decrease in egg quality within 21 days postchallenge. Results indicate that, following a natural route of challenge (eye drop and intranasal), birds vaccinated with the 2005 North Carolina H3N2 subtype were significantly protected from the drop in egg production observed in both the H3N4 vaccinated and sham-vaccinated hens. The results demonstrate that groups receiving vaccines containing either H3 subtype had a decreased number of unsettable eggs, increased hemagglutination inhibition titers following challenge, and decreased virus isolations from cloacal swabs as compared to the sham-vaccinated group. Phylogenetic analysis of the nucleotide sequence of the HA1 gene segment from the three H3 viruses used in these studies indicated that the two North Carolina

  13. Avian influenza virus H9N2 infections in farmed minks.

    PubMed

    Zhang, Chuanmei; Xuan, Yang; Shan, Hu; Yang, Haiyan; Wang, Jianlin; Wang, Ke; Li, Guimei; Qiao, Jian

    2015-11-02

    The prevalence of avian H9N2 viruses throughout Asia, along with their demonstrated ability to infect mammals, puts them high on the list of influenza viruses with pandemic potential for humans. In this study, we investigated whether H9N2 viruses could infect farmed minks. First, we conducted a serological survey for avian influenza virus antibodies on a random sample of the field-trial population of farmed minks. Then we inoculated farmed minks with A/Chicken/Hebei/4/2008 H9N2 viruses and observed the potential pathogenicity of H9N2 virus and virus shedding in infected minks. H9 influenza antibodies could be detected in most farmed minks with a higher seropositivity, which indicated that farmed minks had the high prevalence of exposure to H9 viruses. After infection, the minks displayed the slight clinical signs including lethargy and initial weight loss. The infected lungs showed the mild diffuse pneumonia with thickened alveolar walls and inflammatory cellular infiltration. Influenza virus detection showed that viruses were detected in the allantoic fluids inoculated supernatant of lung tissues at 3 and 7 days post-infection (dpi), and found in the nasal swabs of H9N2-infected minks at 3-11 dpi, suggesting that H9N2 viruses replicated in the respiratory organ, were then shed outwards. HI antibody test showed that antibody levels began to rise at 7 dpi. Our data provided the serological and experimental evidences that strongly suggested farmed minks under the natural state were susceptible to H9N2 viral infection and might be the H9N2 virus carriers. It is imperative to strengthen the H9N2 viral monitoring in farmed minks and pay urgent attention to prevent and control new influenza viruses pandemic prevalence.

  14. A Single-Amino-Acid Substitution at Position 225 in Hemagglutinin Alters the Transmissibility of Eurasian Avian-Like H1N1 Swine Influenza Virus in Guinea Pigs.

    PubMed

    Wang, Zeng; Yang, Huanliang; Chen, Yan; Tao, Shiyu; Liu, Liling; Kong, Huihui; Ma, Shujie; Meng, Fei; Suzuki, Yasuo; Qiao, Chuanling; Chen, Hualan

    2017-11-01

    Efficient transmission from human to human is the prerequisite for an influenza virus to cause a pandemic; however, the molecular determinants of influenza virus transmission are still largely unknown. In this study, we explored the molecular basis for transmission of Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses by comparing two viruses that are genetically similar but differ in their transmissibility in guinea pigs: the A/swine/Guangxi/18/2011 virus (GX/18) is highly transmissible by respiratory droplet in guinea pigs, whereas the A/swine/Heilongjiang/27/2012 virus (HLJ/27) does not transmit in this animal model. We used reverse genetics to generate a series of reassortants and mutants in the GX/18 background and tested their transmissibility in guinea pigs. We found that a single-amino-acid substitution of glycine (G) for glutamic acid (E) at position 225 (E225G) in the HA1 protein completely abolished the respiratory droplet transmission of GX/18, whereas the substitution of E for G at the same position (G225E) in HA1 enabled HLJ/27 to transmit in guinea pigs. We investigated the underlying mechanism and found that viruses bearing 225E in HA1 replicated more rapidly than viruses bearing 225G due to differences in assembly and budding efficiencies. Our study indicates that the amino acid 225E in HA1 plays a key role in EAH1N1 swine influenza virus transmission and provides important information for evaluating the pandemic potential of field influenza virus strains. IMPORTANCE Efficient transmission among humans is a prerequisite for a novel influenza virus to cause a human pandemic. Transmissibility of influenza viruses is a polygenic trait, and understanding the genetic determinants for transmissibility will provide useful insights for evaluating the pandemic potential of influenza viruses in the field. Several amino acids in the hemagglutinin (HA) protein of influenza viruses have been shown to be important for transmissibility, usually by

  15. Development of a real-time RT-PCR assay for a novel influenza A (H1N1) virus.

    PubMed

    Jiang, Tao; Kang, Xiaoping; Deng, Yongqiang; Zhao, Hui; Li, Xiaofeng; Yu, Xuedong; Yu, Man; Qin, Ede; Zhu, Qingyu; Yang, Yinhui; Qin, Chengfeng

    2010-02-01

    A pandemic caused by a novel influenza A virus (H1N1) poses a serious public health threat. In this study, a real-time reverse transcriptase PCR (RT-PCR) assay based on the hemagglutinin gene was developed that discriminates the novel H1N1 from swine influenza virus, seasonal H1N1/H3N2 virus and the highly pathogenic H5N1 avian influenza virus. The sensitivity of this assay was 0.2 50% tissue culture infective dose of virus and 200 copies of in vitro-transcribed target RNA. Three hundred and forty-eight clinical specimens from suspected H1N1 patients were tested using this assay, and forty-two (12.07%) were found to be positive. Tests using the real-time PCR assay recommended by WHO and virus isolation gave identical results. This sensitive and specific real-time RT-PCR assay will contribute to the early diagnosis and control of the emerging H1N1 influenza pandemic. 2009 Elsevier B.V. All rights reserved.

  16. Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort.

    PubMed

    Fragaszy, Ellen; Ishola, David A; Brown, Ian H; Enstone, Joanne; Nguyen-Van-Tam, Jonathan S; Simons, Robin; Tucker, Alexander W; Wieland, Barbara; Williamson, Susanna M; Hayward, Andrew C; Wood, James L N

    2016-07-01

    Pigs are mixing vessels for influenza viral reassortment, but the extent of influenza transmission between swine and humans is not well understood. To assess whether occupational exposure to pigs is a risk factor for human infection with human and swine-adapted influenza viruses. UK pig industry workers were frequency-matched on age, region, sampling month, and gender with a community-based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres ≥ 40 considered seropositive and indicative of infection). Virus-specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity. Forty-two percent of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CIs), adjusted odds ratio after accounting for possible cross-reactivity with other swine A(H1) viruses (aOR) 25·3, 95% CI (1·4-536·3), P = 0·028. The results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunisation of pig industry workers may reduce transmission and the potential for virus reassortment. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  17. Modelling the progression of pandemic influenza A (H1N1) in Vietnam and the opportunities for reassortment with other influenza viruses

    PubMed Central

    Boni, Maciej F; Manh, Bui Huu; Thai, Pham Quang; Farrar, Jeremy; Hien, Tran Tinh; Hien, Nguyen Tran; Van Kinh, Nguyen; Horby, Peter

    2009-01-01

    Background A novel variant of influenza A (H1N1) is causing a pandemic and, although the illness is usually mild, there are concerns that its virulence could change through reassortment with other influenza viruses. This is of greater concern in parts of Southeast Asia, where the population density is high, influenza is less seasonal, human-animal contact is common and avian influenza is still endemic. Methods We developed an age- and spatially-structured mathematical model in order to estimate the potential impact of pandemic H1N1 in Vietnam and the opportunities for reassortment with animal influenza viruses. The model tracks human infection among domestic animal owners and non-owners and also estimates the numbers of animals may be exposed to infected humans. Results In the absence of effective interventions, the model predicts that the introduction of pandemic H1N1 will result in an epidemic that spreads to half of Vietnam's provinces within 57 days (interquartile range (IQR): 45-86.5) and peaks 81 days after introduction (IQR: 62.5-121 days). For the current published range of the 2009 H1N1 influenza's basic reproductive number (1.2-3.1), we estimate a median of 410,000 cases among swine owners (IQR: 220,000-670,000) with 460,000 exposed swine (IQR: 260,000-740,000), 350,000 cases among chicken owners (IQR: 170,000-630,000) with 3.7 million exposed chickens (IQR: 1.9 M-6.4 M), and 51,000 cases among duck owners (IQR: 24,000 - 96,000), with 1.2 million exposed ducks (IQR: 0.6 M-2.1 M). The median number of overall human infections in Vietnam for this range of the basic reproductive number is 6.4 million (IQR: 4.4 M-8.0 M). Conclusion It is likely that, in the absence of effective interventions, the introduction of a novel H1N1 into a densely populated country such as Vietnam will result in a widespread epidemic. A large epidemic in a country with intense human-animal interaction and continued co-circulation of other seasonal and avian viruses would provide

  18. Origins and Evolutionary Dynamics of H3N2 Canine Influenza Virus.

    PubMed

    Zhu, Henan; Hughes, Joseph; Murcia, Pablo R

    2015-05-01

    Influenza A viruses (IAVs) are maintained mainly in wild birds, and despite frequent spillover infections of avian IAVs into mammals, only a small number of viruses have become established in mammalian hosts. A new H3N2 canine influenza virus (CIV) of avian origin emerged in Asia in the mid-2000s and is now circulating in dog populations of China and South Korea, and possibly in Thailand. The emergence of CIV provides new opportunities for zoonotic infections and interspecies transmission. We examined 14,764 complete IAV genomes together with all CIV genomes publicly available since its first isolation until 2013. We show that CIV may have originated as early as 1999 as a result of segment reassortment among Eurasian and North American avian IAV lineages. We also identified amino acid changes that might have played a role in CIV emergence, some of which have not been previously identified in other cross-species jumps. CIV evolves at a lower rate than H3N2 human influenza viruses do, and viral phylogenies exhibit geographical structure compatible with high levels of local transmission. We detected multiple intrasubtypic and heterosubtypic reassortment events, including the acquisition of the NS segment of an H5N1 avian influenza virus that had previously been overlooked. In sum, our results provide insight into the adaptive changes required by avian viruses to establish themselves in mammals and also highlight the potential role of dogs to act as intermediate hosts in which viruses with zoonotic and/or pandemic potential could originate, particularly with an estimated dog population of ∼ 700 million. Influenza A viruses circulate in humans and animals. This multihost ecology has important implications, as past pandemics were caused by IAVs carrying gene segments of both human and animal origin. Adaptive evolution is central to cross-species jumps, and this is why understanding the evolutionary processes that shape influenza A virus genomes is key to elucidating

  19. Transmission of influenza A viruses between pigs and people, Iowa, 2002-2004.

    PubMed

    Terebuh, Pauline; Olsen, Christopher W; Wright, Jennifer; Klimov, Alexander; Karasin, Alexander; Todd, Karla; Zhou, Hong; Hall, Henrietta; Xu, Xiyan; Kniffen, Tim; Madsen, David; Garten, Rebecca; Bridges, Carolyn B

    2010-11-01

    Triple-reassortant (tr) viruses of human, avian, and swine origin, including H1N1, H1N2, and H3N2 subtypes, emerged in North American swine herds in 1998 and have become predominant. While sporadic human infections with classical influenza A (H1N1) and with tr-swine influenza viruses have been reported, relatively few have been documented in occupationally exposed swine workers (SW). We conducted a 2-year (2002-2004) prospective cohort study of transmission of influenza viruses between pigs and SW from a single pork production company in Iowa. Respiratory samples were collected and tested for influenza viruses from SW and from pigs under their care through surveillance for influenza-like illnesses (ILI). Serial blood samples from study participants were tested by hemagglutination inhibition (HI) for antibody seroconversion against human and swine influenza viruses (SIV), and antibody seroprevalence was compared to age-matched urban Iowa blood donors. During the first year, 15 of 88 SW had ILI and were sampled; all were culture-negative for influenza. During the second year, 11 of 76 SW had ILI and were sampled; one was culture-positive for a human seasonal H3N2 virus. Among 20 swine herd ILI outbreaks sampled, influenza A virus was detected by rRT-PCR from 17 with 11 trH1N1 and five trH3N2 virus isolates cultured. During both years, HI geometric mean titers were significantly higher among SW compared to blood donor controls for three SIV: classical swine Sw/WI/238/97 (H1N1), tr Sw/IN/9K035/99 (H1N2), and trSw/IA/H02NJ56371/02 (H1N1)] (P < 0·0001). SW had serologic evidence for infection with both swine and human influenza viruses and were exposed to diverse influenza virus strains circulating in pigs. Influenza virus surveillance among pigs and SW should be encouraged to better understand cross-species transmission and diversity of influenza viruses at the human-swine interface. © 2010 Blackwell Publishing Ltd.

  20. Primer development to obtain complete coding sequence of HA and NA genes of influenza A/H3N2 virus.

    PubMed

    Agustiningsih, Agustiningsih; Trimarsanto, Hidayat; Setiawaty, Vivi; Artika, I Made; Muljono, David Handojo

    2016-08-30

    Influenza is an acute respiratory illness and has become a serious public health problem worldwide. The need to study the HA and NA genes in influenza A virus is essential since these genes frequently undergo mutations. This study describes the development of primer sets for RT-PCR to obtain complete coding sequence of Hemagglutinin (HA) and Neuraminidase (NA) genes of influenza A/H3N2 virus from Indonesia. The primers were developed based on influenza A/H3N2 sequence worldwide from Global Initiative on Sharing All Influenza Data (GISAID) and further tested using Indonesian influenza A/H3N2 archived samples of influenza-like illness (ILI) surveillance from 2008 to 2009. An optimum RT-PCR condition was acquired for all HA and NA fragments designed to cover complete coding sequence of HA and NA genes. A total of 71 samples were successfully sequenced for complete coding sequence both of HA and NA genes out of 145 samples of influenza A/H3N2 tested. The developed primer sets were suitable for obtaining complete coding sequences of HA and NA genes of Indonesian samples from 2008 to 2009.

  1. Co-infection of classic swine H1N1 influenza virus in pigs persistently infected with porcine rubulavirus.

    PubMed

    Rivera-Benitez, José Francisco; De la Luz-Armendáriz, Jazmín; Saavedra-Montañez, Manuel; Jasso-Escutia, Miguel Ángel; Sánchez-Betancourt, Ivan; Pérez-Torres, Armando; Reyes-Leyva, Julio; Hernández, Jesús; Martínez-Lara, Atalo; Ramírez-Mendoza, Humberto

    2016-02-29

    Porcine rubulavirus (PorPV) and swine influenza virus infection causes respiratory disease in pigs. PorPV persistent infection could facilitate the establishment of secondary infections. The aim of this study was to analyse the pathogenicity of classic swine H1N1 influenza virus (swH1N1) in growing pigs persistently infected with porcine rubulavirus. Conventional six-week-old pigs were intranasally inoculated with PorPV, swH1N1, or PorPV/swH1N1. A mock-infected group was included. The co-infection with swH1N1 was at 44 days post-infection (DPI), right after clinical signs of PorPV infection had stopped. The pigs of the co-infection group presented an increase of clinical signs compared to the simple infection groups. In all infected groups, the most recurrent lung lesion was hyperplasia of the bronchiolar-associated lymphoid tissue and interstitial pneumonia. By means of immunohistochemical evaluation it was possible to demonstrate the presence of the two viral agents infecting simultaneously the bronchiolar epithelium. Viral excretion of PorPV in nasal and oral fluid was recorded at 28 and 52 DPI, respectively. PorPV persisted in several samples from respiratory tissues (RT), secondary lymphoid organs (SLO), and bronchoalveolar lavage fluid (BALF). For swH1N1, the viral excretion in nasal fluids was significantly higher in single-infected swH1N1 pigs than in the co-infected group. However, the co-infection group exhibited an increase in the presence of swH1N1 in RT, SLO, and BALF at two days after co-infection. In conclusion, the results obtained confirm an increase in the clinical signs of infection, and PorPV was observed to impact the spread of swH1N1 in analysed tissues in the early stage of co-infection, although viral shedding was not enhanced. In the present study, the interaction of swH1N1 infection is demonstrated in pigs persistently infected with PorPV. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Modified vaccinia virus Ankara expressing the hemagglutinin of pandemic (H1N1) 2009 virus induces cross-protective immunity against Eurasian 'avian-like' H1N1 swine viruses in mice.

    PubMed

    Castrucci, Maria R; Facchini, Marzia; Di Mario, Giuseppina; Garulli, Bruno; Sciaraffia, Ester; Meola, Monica; Fabiani, Concetta; De Marco, Maria A; Cordioli, Paolo; Siccardi, Antonio; Kawaoka, Yoshihiro; Donatelli, Isabella

    2014-05-01

    To examine cross-reactivity between hemagglutinin (HA) derived from A/California/7/09 (CA/09) virus and that derived from representative Eurasian "avian-like" (EA) H1N1 swine viruses isolated in Italy between 1999 and 2008 during virological surveillance in pigs. Modified vaccinia virus Ankara (MVA) expressing the HA gene of CA/09 virus (MVA-HA-CA/09) was used as a vaccine to investigate cross-protective immunity against H1N1 swine viruses in mice. Two classical swine H1N1 (CS) viruses and four representative EA-like H1N1 swine viruses previously isolated during outbreaks of respiratory disease in pigs on farms in Northern Italy were used in this study. Female C57BL/6 mice were vaccinated with MVA/HA/CA/09 and then challenged intranasally with H1N1 swine viruses. Cross-reactive antibody responses were determined by hemagglutination- inhibition (HI) and virus microneutralizing (MN) assays of sera from MVA-vaccinated mice. The extent of protective immunity against infection with H1N1 swine viruses was determined by measuring lung viral load on days 2 and 4 post-challenge. Systemic immunization of mice with CA/09-derived HA, vectored by MVA, elicited cross-protective immunity against recent EA-like swine viruses. This immune protection was related to the levels of cross-reactive HI antibodies in the sera of the immunized mice and was dependent on the similarity of the antigenic site Sa of H1 HAs. Our findings suggest that the herd immunity elicited in humans by the pandemic (H1N1) 2009 virus could limit the transmission of recent EA-like swine HA genes into the influenza A virus gene pool in humans. © 2013 The Authors Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  3. Are People Living Near Modern Swine Production Facilities at Increased Risk of Influenza Virus Infection?

    PubMed

    Lantos, Paul M; Hoffman, Kate; Höhle, Michael; Anderson, Benjamin; Gray, Gregory C

    2016-12-15

    Swine can harbor influenza viruses that are pathogenic to humans. Previous studies support an increased risk of human influenza cases among individuals with swine contact. North Carolina has the second-largest swine industry in the United States.  We investigated the spatiotemporal association between influenza-like illnesses (ILIs) and licensed swine operations from 2008 to 2012 in North Carolina. We determined the week in which ILI cases peaked and statistically estimated their week of onset. This was performed for all 100 North Carolina counties for 4 consecutive influenza seasons. We used linear models to correlate the number of permitted swine operations per county with the weeks of onset and peak ILI activity.  We found that during the 2009-2010 and 2010-2011 influenza seasons, both seasons in which the pandemic 2009 H1N1 influenza A virus circulated, ILI peaked earlier in counties with a higher number of licensed swine operations. We did not observe this in 2008-2009 or 2011-2012, nor did we observe a relationship between ILI onset week and number of swine operations.  Our findings suggest that concentrated swine feeding operations amplified transmission of influenza during years in which H1N1 was circulating. This has implications for vaccine strategies targeting swine workers, as well as virologic surveillance in areas with large concentrations of swine. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  4. Drug susceptibility of influenza A/H3N2 strains co-circulating during 2009 influenza pandemic: first report from Mumbai.

    PubMed

    Gohil, Devanshi J; Kothari, Sweta T; Shinde, Pramod S; Chintakrindi, Anand S; Meharunkar, Rhuta; Warke, Rajas V; Kanyalkar, Meena A; Chowdhary, Abhay S; Deshmukh, Ranjana A

    2015-01-01

    From its first instance in 1977, resistance to amantadine, a matrix (M2) inhibitor has been increasing among influenza A/H3N2, thus propelling the use of oseltamivir, a neuraminidase (NA) inhibitor as a next line drug. Information on drug susceptibility to amantadine and neuraminidase inhibitors for influenza A/H3N2 viruses in India is limited with no published data from Mumbai. This study aimed at examining the sensitivity to M2 and NA inhibitors of influenza A/H3N2 strains isolated from 2009 to 2011 in Mumbai. Nasopharyngeal swabs positive for influenza A/H3N2 virus were inoculated on Madin-Darby canine kidney (MDCK) cell line for virus isolation. Molecular analysis of NA and M2 genes was used to detect known mutations contributing to resistance. Resistance to neuraminidase was assayed using a commercially available chemiluminescence based NA-Star assay kit. Genotypically, all isolates were observed to harbor mutations known to confer resistance to amantadine. However, no know mutations conferring resistance to NA inhibitors were detected. The mean IC50 value for oseltamivir was 0.25 nM. One strain with reduced susceptibility to the neuraminidase inhibitor (IC₅₀=4.08 nM) was isolated from a patient who had received oseltamivir treatment. Phylogenetic analysis postulate the emergence of amantadine resistance in Mumbai may be due to genetic reassortment with the strains circulating in Asia and North America. Surveillance of drug susceptibility helped us to identify an isolate with reduced sensitivity to oseltamivir. Therefore, we infer that such surveillance would help in understanding possible trends underlying the emergence of resistant variants in humans. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. New Influenza A/H1N1 (“Swine Flu”): information needs of airport passengers and staff

    PubMed Central

    Dickmann, P.; Rubin, G. J.; Gaber, W.; Wessely, S.; Wicker, S.; Serve, H.; Gottschalk, R.

    2010-01-01

    Please cite this paper as: Dickmann et al. (2010) New Influenza A/H1N1 (“Swine Flu”): information needs of airport passengers and staff. . Influenza and Other Respiratory Viruses 5(1), 39–46. Background  Airports are the entrances of infectious diseases. Particularly at the beginning of an outbreak, information and communication play an important role to enable the early detection of signs or symptoms and to encourage passengers to adopt appropriate preventive behaviour to limit the spread of the disease. Objectives  To determine the adequacy of the information provided to airport passengers and staff in meeting their information needs in relation to their concerns. Methods  At the start of the influenza A/H1N1 epidemic (29–30 April 2009), qualitative semi‐structured interviews (N = 101) were conducted at Frankfurt International Airport with passengers who were either returning from or going to Mexico and with airport staff who had close contact with these passengers. Interviews focused on knowledge about swine flu, information needs and fear or concern about the outbreak. Results  The results showed that a desire for more information was associated with higher concern – the least concerned participants did not want any additional information, while the most concerned participants reported a range of information needs. Airport staff in contact with passengers travelling from the epicentre of the outbreak showed the highest levels of fear or concern, coupled with a desire to be adequately briefed by their employer. Conclusions  Our results suggest that information strategies should address not only the exposed or potentially exposed but also groups that feel at risk. Identifying what information these different passenger and staff groups wish to receive will be an important task in any future infectious disease outbreak. PMID:21138539

  6. Intercontinental circulation of human influenza A(H1N2) reassortant viruses during the 2001-2002 influenza season.

    PubMed

    Xu, Xiyan; Smith, Catherine B; Mungall, Bruce A; Lindstrom, Stephen E; Hall, Henrietta E; Subbarao, Kanta; Cox, Nancy J; Klimov, Alexander

    2002-11-15

    Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.

  7. Molecular analyses of H3N2 canine influenza viruses isolated from Korea during 2013-2014.

    PubMed

    Lee, EunJung; Kim, Eun-Ju; Kim, Bo-Hye; Song, Jae-Young; Cho, In-Soo; Shin, Yeun-Kyung

    2016-04-01

    Canine influenza A virus (CIV) causes a respiratory disease among dog populations and is prevalent in North America and Asia. Recently, Asian H3N2 CIV infection has been of particular concern, with recent reports related to reassortants with pandemic 2009 strains, direct transmission from a human H3N2, a possibility of H3N2 CIV transmission to other mammals, and even the first outbreak of H3N2 CIVs in North America in April 2015. However, despite these global concerns, our understanding of how influenza A virus transmission impacts the overall populations of H3N2 CIVs remains incomplete. Hence, we investigated the evolutionary history of the most recent two Korean CIV isolates, A/canine/Korea/BD-1/2013 and A/canine/Korea/DG1/2014, along with 57 worldwide CIVs, using comprehensive molecular analyses based on genomic genotyping. This study presents that the new Korean CIV isolates are closely related to the predominantly circulating H3N2 CIVs with genotypes K, G, E, 3B, F, 2D, F, and 1E, carrying several mutations in antigenic and host determinant sites. Also, our findings show that the genome-wide genetic variations within the H3N2 CIVs are low; however, two antigenic protein (HA and NA) analysis demonstrates genetic diversification of the H3N2 CIVs, which evolves independently between Korea and China.

  8. Genomic reassortment of influenza A virus in North American swine, 1998–2011

    PubMed Central

    Detmer, Susan E.; Wentworth, David E.; Tan, Yi; Schwartzbard, Aaron; Halpin, Rebecca A.; Stockwell, Timothy B.; Lin, Xudong; Vincent, Amy L.; Gramer, Marie R.; Holmes, Edward C.

    2012-01-01

    Revealing the frequency and determinants of reassortment among RNA genome segments is fundamental to understanding basic aspects of the biology and evolution of the influenza virus. To estimate the extent of genomic reassortment in influenza viruses circulating in North American swine, we performed a phylogenetic analysis of 139 whole-genome viral sequences sampled during 1998–2011 and representing seven antigenically distinct viral lineages. The highest amounts of reassortment were detected between the H3 and the internal gene segments (PB2, PB1, PA, NP, M and NS), while the lowest reassortment frequencies were observed among the H1γ, H1pdm and neuraminidase segments, particularly N1. Less reassortment was observed among specific haemagglutinin–neuraminidase combinations that were more prevalent in swine, suggesting that some genome constellations may be evolutionarily more stable. PMID:22993190

  9. The neuropsychiatric aspects of influenza/swine flu: A selective review

    PubMed Central

    Manjunatha, Narayana; Math, Suresh Bada; Kulkarni, Girish Baburao; Chaturvedi, Santosh Kumar

    2011-01-01

    The world witnessed the influenza virus during the seasonal epidemics and pandemics. The current strain of H1N1 (swine flu) pandemic is believed to be the legacy of the influenza pandemic (1918-19). The influenza virus has been implicated in many neuropsychiatric disorders. In view of the recent pandemic, it would be interesting to review the neuropsychiatric aspects of influenza, specifically swine flu. Author used popular search engine ‘PUBMED’ to search for published articles with different MeSH terms using Boolean operator (AND). Among these, a selective review of the published literature was done. Acute manifestations of swine flu varied from behavioral changes, fear of misdiagnosis during outbreak, neurological features like seizures, encephalopathy, encephalitis, transverse myelitis, aseptic meningitis, multiple sclerosis, and Guillian-Barre Syndrome. Among the chronic manifestations, schizophrenia, Parkinson's disease, mood disorder, dementia, and mental retardation have been hypothesized. Further research is required to understand the etiological hypothesis of the chronic manifestations of influenza. The author urges neuroscientists around the world to make use of the current swine flu pandemic as an opportunity for further research. PMID:23271861

  10. The neuropsychiatric aspects of influenza/swine flu: A selective review.

    PubMed

    Manjunatha, Narayana; Math, Suresh Bada; Kulkarni, Girish Baburao; Chaturvedi, Santosh Kumar

    2011-07-01

    The world witnessed the influenza virus during the seasonal epidemics and pandemics. The current strain of H1N1 (swine flu) pandemic is believed to be the legacy of the influenza pandemic (1918-19). The influenza virus has been implicated in many neuropsychiatric disorders. In view of the recent pandemic, it would be interesting to review the neuropsychiatric aspects of influenza, specifically swine flu. Author used popular search engine 'PUBMED' to search for published articles with different MeSH terms using Boolean operator (AND). Among these, a selective review of the published literature was done. Acute manifestations of swine flu varied from behavioral changes, fear of misdiagnosis during outbreak, neurological features like seizures, encephalopathy, encephalitis, transverse myelitis, aseptic meningitis, multiple sclerosis, and Guillian-Barre Syndrome. Among the chronic manifestations, schizophrenia, Parkinson's disease, mood disorder, dementia, and mental retardation have been hypothesized. Further research is required to understand the etiological hypothesis of the chronic manifestations of influenza. The author urges neuroscientists around the world to make use of the current swine flu pandemic as an opportunity for further research.

  11. Genetic Compatibility and Virulence of Reassortants Derived from Contemporary Avian H5N1 and Human H3N2 Influenza A Viruses

    PubMed Central

    Zhou, Hong; Cox, Nancy J.; Donis, Ruben O.

    2008-01-01

    The segmented structure of the influenza virus genome plays a pivotal role in its adaptation to new hosts and the emergence of pandemics. Despite concerns about the pandemic threat posed by highly pathogenic avian influenza H5N1 viruses, little is known about the biological properties of H5N1 viruses that may emerge following reassortment with contemporary human influenza viruses. In this study, we used reverse genetics to generate the 63 possible virus reassortants derived from H5N1 and H3N2 viruses, containing the H5N1 surface protein genes, and analyzed their viability, replication efficiency, and mouse virulence. Specific constellations of avian–human viral genes proved deleterious for viral replication in cell culture, possibly due to disruption of molecular interaction networks. In particular, striking phenotypes were noted with heterologous polymerase subunits, as well as NP and M, or NS. However, nearly one-half of the reassortants replicated with high efficiency in vitro, revealing a high degree of compatibility between avian and human virus genes. Thirteen reassortants displayed virulent phenotypes in mice and may pose the greatest threat for mammalian hosts. Interestingly, one of the most pathogenic reassortants contained avian PB1, resembling the 1957 and 1968 pandemic viruses. Our results reveal the broad spectrum of phenotypes associated with H5N1/H3N2 reassortment and a possible role for the avian PB1 in the emergence of pandemic influenza. These observations have important implications for risk assessment of H5N1 reassortant viruses detected in surveillance programs. PMID:18497857

  12. Pre-infection of pigs with Mycoplasma hyopneumoniae induces oxidative stress that influences outcomes of a subsequent infection with a swine influenza virus of H1N1 subtype.

    PubMed

    Deblanc, C; Robert, F; Pinard, T; Gorin, S; Quéguiner, S; Gautier-Bouchardon, A V; Ferré, S; Garraud, J M; Cariolet, R; Brack, M; Simon, G

    2013-03-23

    The severity of swine influenza is highly variable and can be exacerbated by many factors, such as a pre-infection of pigs with Mycoplasma hyopneumoniae (Mhp). The aim of this study was to investigate the oxidative stress induced by Mhp and the impact of this stress on the evolution of an infection with the European avian-like swine H1N1 influenza virus. Two experimental trials (E1 and E2), which differed only by the feed delivered to the animals, were conducted on SPF pigs. In each trial, one group of nine 6-week-old pigs was inoculated intra-tracheally with Mhp and H1N1 at 21 days intervals and a mock-infected group (8 pigs) was included. Clinical signs were observed, blood samples were collected throughout the study and pathogens were detected in nasal swabs and lung tissues. Results indicated that Mhp infection induced an oxidative stress in E1 and E2, but its level was more important in E2 than in E1 three weeks post-Mhp inoculation, before H1N1 infection. In both trials, a strong inflammatory response and a response to the oxidative stress previously induced by Mhp appeared after H1N1 infection. However, the severity of influenza disease was significantly more marked in E2 as compared to E1, as revealed by prolonged hyperthermia, stronger reduction in mean daily weight gain and earlier viral shedding. These results suggested that severity of flu syndrome and reduction in animal performance may vary depending on the level of oxidative stress at the moment of the influenza infection, and that host responses could be influenced by the feed. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Comparative analysis of MicroRNA expression in dog lungs infected with the H3N2 and H5N1 canine influenza viruses.

    PubMed

    Zheng, Yun; Fu, Xinliang; Wang, Lifang; Zhang, Wenyan; Zhou, Pei; Zhang, Xin; Zeng, Weijie; Chen, Jidang; Cao, Zongxi; Jia, Kun; Li, Shoujun

    2018-05-14

    MicroRNAs, a class of noncoding RNAs 18 to 23 nucleotides (nt) in length, play critical roles in a wide variety of biological processes. The objective of this study was to examine differences in microRNA expression profiles derived from the lungs of beagle dogs infected with the avian-origin H3N2 canine influenza virus (CIV) or the highly pathogenic avian influenza (HPAI) H5N1 virus (canine-origin isolation strain). After dogs were infected with H3N2 or H5N1, microRNA expression in the lungs was assessed using a deep-sequencing approach. To identify the roles of microRNAs in viral pathogenicity and the host immune response, microRNA target genes were predicted, and their functions were analyzed using bioinformatics software. A total of 229 microRNAs were upregulated in the H5N1 infection group compared with those in the H3N2 infection group, and 166 microRNAs were downregulated. MicroRNA target genes in the H5N1 group were more significantly involved in metabolic pathways, such as glycerolipid metabolism and glycerophospholipid metabolism, than those in the H3N2 group. The inhibition of metabolic pathways may lead to appetite loss, weight loss and weakened immunity. Moreover, miR-485, miR-144, miR-133b, miR-4859-5p, miR-6902-3p, miR-7638, miR-1307-3p and miR-1346 were significantly altered microRNAs that potentially led to the inhibition of innate immune pathways and the heightened pathogenicity of H5N1 compared with that of H3N2 in dogs. This study deepens our understanding of the complex relationships among microRNAs, the influenza virus-mediated immune response and immune injury in dogs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. One-Health Simulation Modelling: A Case Study of Influenza Spread between Human and Swine Populations using NAADSM.

    PubMed

    Dorjee, S; Revie, C W; Poljak, Z; McNab, W B; Sanchez, J

    2016-02-01

    The circulation of zoonotic influenza A viruses including pH1N1 2009 and H5N1 continue to present a constant threat to animal and human populations. Recently, an H3N2 variant spread from pigs to humans and between humans in limited numbers. Accordingly, this research investigated a range of scenarios of the transmission dynamics of pH1N1 2009 virus at the swine-human interface while accounting for different percentages of swine workers initially immune. Furthermore, the feasibility of using NAADSM (North American Animal Disease Spread Model) applied as a one-health simulation model was assessed. The study population included 488 swine herds and 29, 707 households of people within a county in Ontario, Canada. Households were categorized as follows: (i) rural households with swine workers, (ii) rural households without swine workers, and (iii) urban households without swine workers. Forty-eight scenarios were investigated, based on the combination of six scenarios around the transmissibility of the virus at the interface and four vaccination coverage levels of swine workers (0-60%), all under two settings of either swine or human origin of the virus. Outcomes were assessed in terms of stochastic 'die-out' fraction, size and time to peak epidemic day, overall size and duration of the outbreaks. The modelled outcomes indicated that minimizing influenza transmissibility at the interface and targeted vaccination of swine workers had significant beneficial effects. Our results indicate that NAADSM can be used as a framework to model the spread and control of contagious zoonotic diseases among animal and human populations, under certain simplifying assumptions. Further evaluation of the model is required. In addition to these specific findings, this study serves as a benchmark that can provide useful input to a future one-health influenza modelling studies. Some pertinent information gaps were also identified. Enhanced surveillance and the collection of high

  15. Genome-Wide Analysis of Evolutionary Markers of Human Influenza A(H1N1)pdm09 and A(H3N2) Viruses May Guide Selection of Vaccine Strain Candidates.

    PubMed

    Belanov, Sergei S; Bychkov, Dmitrii; Benner, Christian; Ripatti, Samuli; Ojala, Teija; Kankainen, Matti; Kai Lee, Hong; Wei-Tze Tang, Julian; Kainov, Denis E

    2015-11-27

    Here we analyzed whole-genome sequences of 3,969 influenza A(H1N1)pdm09 and 4,774 A(H3N2) strains that circulated during 2009-2015 in the world. The analysis revealed changes at 481 and 533 amino acid sites in proteins of influenza A(H1N1)pdm09 and A(H3N2) strains, respectively. Many of these changes were introduced as a result of random drift. However, there were 61 and 68 changes that were present in relatively large number of A(H1N1)pdm09 and A(H3N2) strains, respectively, that circulated during relatively long time. We named these amino acid substitutions evolutionary markers, as they seemed to contain valuable information regarding the viral evolution. Interestingly, influenza A(H1N1)pdm09 and A(H3N2) viruses acquired non-overlapping sets of evolutionary markers. We next analyzed these characteristic markers in vaccine strains recommended by the World Health Organization for the past five years. Our analysis revealed that vaccine strains carried only few evolutionary markers at antigenic sites of viral hemagglutinin (HA) and neuraminidase (NA). The absence of these markers at antigenic sites could affect the recognition of HA and NA by human antibodies generated in response to vaccinations. This could, in part, explain moderate efficacy of influenza vaccines during 2009-2014. Finally, we identified influenza A(H1N1)pdm09 and A(H3N2) strains, which contain all the evolutionary markers of influenza A strains circulated in 2015, and which could be used as vaccine candidates for the 2015/2016 season. Thus, genome-wide analysis of evolutionary markers of influenza A(H1N1)pdm09 and A(H3N2) viruses may guide selection of vaccine strain candidates. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. International Laboratory Comparison of Influenza Microneutralization Assays for A(H1N1)pdm09, A(H3N2), and A(H5N1) Influenza Viruses by CONSISE

    PubMed Central

    Engelhardt, Othmar G.; Wood, John; Heath, Alan; Katz, Jacqueline M.; Peiris, Malik; Hoschler, Katja; Hungnes, Olav; Zhang, Wenqing; Van Kerkhove, Maria D.

    2015-01-01

    The microneutralization assay is commonly used to detect antibodies to influenza virus, and multiple protocols are used worldwide. These protocols differ in the incubation time of the assay as well as in the order of specific steps, and even within protocols there are often further adjustments in individual laboratories. The impact these protocol variations have on influenza serology data is unclear. Thus, a laboratory comparison of the 2-day enzyme-linked immunosorbent assay (ELISA) and 3-day hemagglutination (HA) microneutralization (MN) protocols, using A(H1N1)pdm09, A(H3N2), and A(H5N1) viruses, was performed by the CONSISE Laboratory Working Group. Individual laboratories performed both assay protocols, on multiple occasions, using different serum panels. Thirteen laboratories from around the world participated. Within each laboratory, serum sample titers for the different assay protocols were compared between assays to determine the sensitivity of each assay and were compared between replicates to assess the reproducibility of each protocol for each laboratory. There was good correlation of the results obtained using the two assay protocols in most laboratories, indicating that these assays may be interchangeable for detecting antibodies to the influenza A viruses included in this study. Importantly, participating laboratories have aligned their methodologies to the CONSISE consensus 2-day ELISA and 3-day HA MN assay protocols to enable better correlation of these assays in the future. PMID:26108286

  17. Global migration of influenza A viruses in swine

    PubMed Central

    Nelson, Martha I.; Viboud, Cécile; Vincent, Amy L.; Culhane, Marie R.; Detmer, Susan E.; Wentworth, David E.; Rambaut, Andrew; Suchard, Marc A.; Holmes, Edward C.; Lemey, Philippe

    2015-01-01

    The complex and unresolved evolutionary origins of the 2009 H1N1 influenza pandemic exposed major gaps in our knowledge of the global spatial ecology and evolution of influenza A viruses in swine (swIAVs). Here we undertake an expansive phylogenetic analysis of swIAV sequence data and demonstrate that the global live swine trade strongly predicts the spatial dissemination of swIAVs, with Europe and North America acting as sources of viruses in Asian countries. In contrast, China has the world’s largest swine population but is not a major exporter of live swine, and is not an important source of swIAVs in neighboring Asian countries or globally. A meta-population simulation model incorporating trade data predicts that the global ecology of swIAVs is more complex than previously thought, and the US and China’s large swine populations are unlikely to be representative of swIAV diversity in their respective geographic regions, requiring independent surveillance efforts throughout Latin America and Asia. PMID:25813399

  18. PREDAC-H3: a user-friendly platform for antigenic surveillance of human influenza a(H3N2) virus based on hemagglutinin sequences.

    PubMed

    Peng, Yousong; Yang, Lei; Li, Honglei; Zou, Yuanqiang; Deng, Lizong; Wu, Aiping; Du, Xiangjun; Wang, Dayan; Shu, Yuelong; Jiang, Taijiao

    2016-08-15

    Timely surveillance of the antigenic dynamics of the influenza virus is critical for accurate selection of vaccine strains, which is important for effective prevention of viral spread and infection. Here, we provide a computational platform, called PREDAC-H3, for antigenic surveillance of human influenza A(H3N2) virus based on the sequence of surface protein hemagglutinin (HA). PREDAC-H3 not only determines the antigenic variants and antigenic cluster (grouped for similar antigenicity) to which the virus belongs, based on HA sequences, but also allows visualization of the spatial distribution and temporal dynamics of antigenic clusters of viruses isolated from around the world, thus assisting in antigenic surveillance of human influenza A(H3N2) virus. It is publicly available from: http://biocloud.hnu.edu.cn/influ411/html/index.php : yshu@cnic.org.cn or taijiao@moon.ibp.ac.cn. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Genetic analysis of human and swine influenza A viruses isolated in Northern Italy during 2010-2015.

    PubMed

    Chiapponi, C; Ebranati, E; Pariani, E; Faccini, S; Luppi, A; Baioni, L; Manfredi, R; Carta, V; Merenda, M; Affanni, P; Colucci, M E; Veronesi, L; Zehender, G; Foni, E

    2018-02-01

    Influenza A virus (IAV) infection in swine plays an important role in the ecology of influenza viruses. The emergence of new IAVs comes through different mechanisms, with the genetic reassortment of genes between influenza viruses, also originating from different species, being common. We performed a genetic analysis on 179 IAV isolates from humans (n. 75) and pigs (n. 104) collected in Northern Italy between 2010 and 2015, to monitor the genetic exchange between human and swine IAVs. No cases of human infection with swine strains were noticed, but direct infections of swine with H1N1pdm09 strains were detected. Moreover, we pointed out a continuous circulation of H1N1pdm09 strains in swine populations evidenced by the introduction of internal genes of this subtype. These events contribute to generating new viral variants-possibly endowed with pandemic potential-and emphasize the importance of continuous surveillance at both animal and human level. © 2017 The Authors. Zoonoses and Public Health published by Blackwell Verlag GmbH.

  20. Replication and transmission of mammalian-adapted H9 subtype influenza virus in pigs and quail

    PubMed Central

    Obadan, Adebimpe O.; Kimble, Brian J.; Rajao, Daniela; Lager, Kelly; Santos, Jefferson J. S.; Vincent, Amy

    2015-01-01

    Influenza A virus is a major pathogen of birds, swine and humans. Strains can jump between species in a process often requiring mutations and reassortment, resulting in outbreaks and, potentially, pandemics. H9N2 avian influenza is predominant in poultry across Asia and occasionally infects humans and swine. Pandemic H1N1 (H1N1pdm) is endemic in humans and swine and has a history of reassortment in pigs. Previous studies have shown the compatibility of H9N2 and H1N1pdm for reassortment in ferrets, a model for human infection and transmission. Here, the effects of ferret adaptation of H9 surface gene segments on the infectivity and transmission in at-risk natural hosts, specifically swine and quail, were analysed. Reassortant H9N1 and H9N2 viruses, carrying seven or six gene segments from H1N1pdm, showed infectivity and transmissibility in swine, unlike the wholly avian H9N2 virus with ferret-adapted surface genes. In quail, only the reassortant H9N2 with the six internal gene segments from the H1N1pdm strain was able to infect and transmit, although less efficiently than the wholly avian H9N2 virus with ferret-adapted surface genes. These results highlight that ferret-adapted mutations on the haemagglutinin of H9 subtype virus do not restrict the ability of the virus to infect swine and quail, and that the ability to transmit in these species depends on the context of the whole virus. As such, this study emphasizes the threat that H9N2 reassortant viruses pose to humans and agricultural species and the importance of the genetic constellation of the virus to its ability to replicate and transmit in natural hosts of influenza. PMID:25986634

  1. Capsular Sialic Acid of Streptococcus suis Serotype 2 Binds to Swine Influenza Virus and Enhances Bacterial Interactions with Virus-Infected Tracheal Epithelial Cells

    PubMed Central

    Wang, Yingchao; Gagnon, Carl A.; Savard, Christian; Music, Nedzad; Srednik, Mariela; Segura, Mariela; Lachance, Claude; Bellehumeur, Christian

    2013-01-01

    Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model. PMID:24082069

  2. Influenza A(H9N2) Virus, Myanmar, 2014-2015.

    PubMed

    Lin, Thant Nyi; Nonthabenjawan, Nutthawan; Chaiyawong, Supassama; Bunpapong, Napawan; Boonyapisitsopa, Supanat; Janetanakit, Taveesak; Mon, Pont Pont; Mon, Hla Hla; Oo, Kyaw Naing; Oo, Sandi Myint; Mar Win, Mar; Amonsin, Alongkorn

    2017-06-01

    Routine surveillance of influenza A virus was conducted in Myanmar during 2014-2015. Influenza A(H9N2) virus was isolated in Shan State, upper Myanmar. Whole-genome sequencing showed that H9N2 virus from Myanmar was closely related to H9N2 virus of clade 4.2.5 from China.

  3. Pathogenicity and transmission of triple reassortant H3N2 swine influenza A viruses is attenuated following Turkey embryo propagation.

    PubMed

    Raghunath, Shobana; Pudupakam, Raghavendra Sumanth; Deventhiran, Jagadeeswaran; Tevatia, Rahul; Leroith, Tanya

    2017-03-01

    Genetic lineages of swine influenza A viruses (SIVs) have recently been established in Turkeys in the United States. To identify molecular determinants that are involved in virulence and transmission of SIVs to Turkeys, we sequentially passaged two triple reassortant H3N2 SIV isolates from Minnesota in ten day old specific-pathogen free (SPF) Turkey embryos and tested them in seven-day old Turkey poults. We found that SIV replication in Turkey embryos led to minimal mutations in and around the receptor binding and antigenic sites of the HA molecule, while other gene segments were unchanged. The predominant changes associated with Turkey embryo passage were A223V, V226A and T248I mutations in the receptor-binding and glycosylation sites of the HA molecule. Furthermore, Turkey embryo propagation altered receptor specificity in SIV strain 07-1145. Embryo passaged 07-1145 virus showed a decrease in α2, 6 sialic acid receptor binding compared to the wild type virus. Intranasal infection of wild type SIVs in one-week-old Turkey poults resulted in persistent diarrhea and all the infected birds seroconverted at ten days post infection. The 07-1145 wild type virus also transmitted to age matched in-contact birds introduced one-day post infection. Turkeys infected with embryo passaged viruses displayed no clinical signs and were not transmitted to in-contact poults. Our results suggest that Turkey embryo propagation attenuates recent TR SIVs for infectivity and transmission in one week old Turkeys. Our findings will have important implications in identifying molecular determinants that control the transmission and virulence of TR SIVs in Turkeys and other species. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Hypothiocyanite produced by human and rat respiratory epithelial cells inactivates extracellular H1N2 influenza A virus.

    PubMed

    Gingerich, Aaron; Pang, Lan; Hanson, Jarod; Dlugolenski, Daniel; Streich, Rebecca; Lafontaine, Eric R; Nagy, Tamás; Tripp, Ralph A; Rada, Balázs

    2016-01-01

    Our aim was to study whether an extracellular, oxidative antimicrobial mechanism inherent to tracheal epithelial cells is capable of inactivating influenza H1N2 virus. Epithelial cells were isolated from tracheas of male Sprague-Dawley rats. Both primary human and rat tracheobronchial epithelial cells were differentiated in air-liquid interface cultures. A/swine/Illinois/02860/09 (swH1N2) influenza A virions were added to the apical side of airway cells for 1 h in the presence or absence of lactoperoxidase or thiocyanate. Characterization of rat epithelial cells (morphology, Duox expression) occurred via western blotting, PCR, hydrogen peroxide production measurement and histology. The number of viable virions was determined by plaque assays. Statistical difference of the results was analyzed by ANOVA and Tukey's test. Our data show that rat tracheobronchial epithelial cells develop a differentiated, polarized monolayer with high transepithelial electrical resistance, mucin production and expression of dual oxidases. Influenza A virions are inactivated by human and rat epithelial cells via a dual oxidase-, lactoperoxidase- and thiocyanate-dependent mechanism. Differentiated air-liquid interface cultures of rat tracheal epithelial cells provide a novel model to study airway epithelium-influenza interactions. The dual oxidase/lactoperoxidase/thiocyanate extracellular oxidative system producing hypothiocyanite is a fast and potent anti-influenza mechanism inactivating H1N2 viruses prior to infection of the epithelium.

  5. Epigallocatechin-3-gallate inhibits TLR4 signaling through the 67-kDa laminin receptor and effectively alleviates acute lung injury induced by H9N2 swine influenza virus.

    PubMed

    Xu, Ming-Ju; Liu, Bao-Jian; Wang, Cun-Lian; Wang, Guo-Hua; Tian, Yong; Wang, Shao-Hua; Li, Jun; Li, Pei-Yao; Zhang, Rui-Hua; Wei, Dong; Tian, Shu-Fei; Xu, Tong

    2017-11-01

    Epigallocatechin-3-gallate (EGCG) was found to inhibit the Toll-like receptor 4 (TLR4) pathway involved in influenza virus pathogenesis. Here, the effect of EGCG on TLR4 in an H9N2 virus-induced acute lung injury mouse model was investigated. BALB/c mice were inoculated intranasally with A/Swine/Hebei/108/2002 (H9N2) virus or noninfectious allantoic fluid, and treated with EGCG and E5564 or normal saline orally for 5 consecutive days. PMVECs were treated with EGCG or anti-67kDa laminin receptor (LR). Lung physiopathology, inflammation, oxidative stress, viral replication, and TLR4/NF-κB/Toll-interacting protein (Tollip) pathway in lung tissue and/or PMVECs were investigated. EGCG attenuated lung histological lesions, decreased lung W/D ratio, cytokines levels, and inhibited MPO activity and prolonged mouse survival. EGCG treatment also markedly downregulated TLR4 and NF-κB protein levels but Tollip expression was upregulated compared with that in untreated H9N2-infected mice (P<0.05). In PMVECs, anti-67LR antibody treatment significantly downregulated Tollip levels; however, the TLR4 and NF-κB protein levels dramatically increased compared with that in the EGCG-treated group (P<0.05). EGCG remarkably downregulated TLR4 protein levels through 67LR/Tollip, decreased MPO activity and inflammatory cytokine levels, supporting EGCG as a potential therapeutic agent for managing acute lung injury induced by H9N2 SIV. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Pathogenic characteristics of a novel triple-reasserted H1N2 swine influenza virus.

    PubMed

    Liu, Huili; Tao, Jie; Zhang, Pengchao; Yin, Xiuchen; Ha, Zhuo; Zhang, Chunling

    2016-07-01

    A novel triple reasserted H1N2 virus A/swine/Shanghai/1/2007 (SH07) was isolated from nasal swabs of weaned pig showing clinical symptoms of coughing and sneezing. To explore the virus characteristics, mice, chickens and pigs were selected for pathogenicity study. Pigs inoculated intranasally with 10(6) TCID50 SH07 showed clinical symptoms with coughing and sneezing, but no death. The virus nuclear acid was detected in many tissues using real-time PCR, which was mainly distributed in respiratory system particularly in the lungs. The virus was low-pathogenic to chickens with 10(6) TCID50 dose inoculation either via intramuscular or intranasal routes. However virus nuclear acid detection and virus isolation confirmed that the virus can also be found in nasal and rectum. When virus was inoculated into mice by intramuscular or intranasal routes we observed 100% and 80% lethality respectively. The third generation of samples passaged on MDCK cell were SIV positive in indirect immunofluorescence assay (IFA) using antiserum against H1N2 SIV. Furthermore, the lungs of mice showed obvious lesion with interstitial pneumonia. Data in our study suggest that SH07 is preferentially pathogenic to mammals rather than birds although it is a reasserting virus with the fragments from swine, human and avian origin. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  7. Effect of previous and current vaccination against influenza A(H1N1)pdm09, A(H3N2), and B during the post-pandemic period 2010-2016 in Spain.

    PubMed

    Gherasim, Alin; Martínez-Baz, Iván; Castilla, Jesús; Pozo, Francisco; Larrauri, Amparo

    2017-01-01

    Recent studies suggest that the protective effect of the current influenza vaccine could be influenced by vaccination in previous seasons. We estimated the combined effect of the previous and current influenza vaccines from the 2010-2011 season to the 2015-2016 season in Spain. We performed a test-negative case-control study in patients ≥9 years old. We estimated the influenza vaccine effectiveness (IVE) against influenza A(H1N1)pdm09, A(H3N2), and B virus. We included 1206 influenza A(H1N1)pdm09 cases, 1358 A(H3N2) cases and 1079 B cases. IVE against A(H1N1)pdm09 virus in the pooled-season analysis was 53% (95% Confidence Interval (CI): 21% to 72%) for those vaccinated only in the current season and 50% (95%CI: 23% to 68%) for those vaccinated in the both current and previous seasons. Against the influenza A(H3N2) virus, IVE was 17% (95%CI: -43% to 52%) for those vaccinated only in the current season and 3% (95%CI: -33% to 28%) for those vaccinated in both seasons. Regarding influenza B, we obtained similar IVEs for those vaccinated only in the current and those vaccinated in both seasons: 57% (95%CI: 12% to 79%) and 56% (95%CI: 36% to 70%), respectively. Our results suggested no interference between the previous and current influenza vaccines against A(H1N1)pdm09 and B viruses, but a possible negative interference against A(H3N2) virus.

  8. DNA vaccination elicits protective immune responses against pandemic and classic swine influenza viruses in pigs.

    PubMed

    Gorres, J Patrick; Lager, Kelly M; Kong, Wing-Pui; Royals, Michael; Todd, John-Paul; Vincent, Amy L; Wei, Chih-Jen; Loving, Crystal L; Zanella, Eraldo L; Janke, Bruce; Kehrli, Marcus E; Nabel, Gary J; Rao, Srinivas S

    2011-11-01

    Swine influenza is a highly contagious viral infection in pigs that significantly impacts the pork industry due to weight loss and secondary infections. There is also the potential of a significant threat to public health, as was seen in 2009 when the pandemic H1N1 influenza virus strain emerged from reassortment events among avian, swine, and human influenza viruses within pigs. As classic and pandemic H1N1 strains now circulate in swine, an effective vaccine may be the best strategy to protect the pork industry and public health. Current inactivated-virus vaccines available for swine influenza protect only against viral strains closely related to the vaccine strain, and egg-based production of these vaccines is insufficient to respond to large outbreaks. DNA vaccines are a promising alternative since they can potentially induce broad-based protection with more efficient production methods. In this study we evaluated the potentials of monovalent and trivalent DNA vaccine constructs to (i) elicit both humoral and gamma interferon (IFN-γ) responses and (ii) protect pigs against viral shedding and lung disease after challenge with pandemic H1N1 or classic swine H1N1 influenza virus. We also compared the efficiency of a needle-free vaccine delivery method to that of a conventional needle/syringe injection. We report that DNA vaccination elicits robust serum antibody and cellular responses after three immunizations and confers significant protection against influenza virus challenge. Needle-free delivery elicited improved antibody responses with the same efficiency as conventional injection and should be considered for development as a practical alternative for vaccine administration.

  9. Exploration of risk factors contributing to the presence of influenza A virus in swine at agricultural fairs

    PubMed Central

    Bowman, Andrew S; Workman, Jeffrey D; Nolting, Jacqueline M; Nelson, Sarah W; Slemons, Richard D

    2014-01-01

    Influenza A virus infections occurring in exhibition swine populations at agricultural fairs during 2012 served as a source of H3N2 variant influenza A viruses transmitted to humans resulting in more than 300 documented cases. Prior to the outbreak, this investigation was initiated to identify fair-level risk factors contributing to influenza A virus infections in pigs at agricultural fairs. As part of an ongoing active surveillance program, nasal swabs and associated fair-level metadata were collected from pigs at 40 junior fair market swine shows held in Ohio during the 2012 fair season. Analyses of the data show that the adjusted odds of having influenza A virus-infected pigs at a fair were 1.27 (95% confidential interval (CI): 1.04–1.66) higher for every 20 pig increase in the size of the swine show. Additionally, four of the five fairs that hosted breeding swine shows in addition to their junior fair market swine shows had pigs test positive for influenza A virus. While the current study was limited to 40 fairs within one state, the findings provided insight for veterinary and public health officials developing mitigation strategies to decrease the intra- and inter-species transmission of influenza A virus at fairs. PMID:26038494

  10. Genetic drift of influenza A(H3N2) viruses during two consecutive seasons in 2011-2013 in Corsica, France.

    PubMed

    Fantoni, Anais; Arena, Christophe; Corrias, Laura; Salez, Nicolas; de Lamballerie, Xavier Nicolas; Amoros, Jean Pierre; Blanchon, Thierry; Varesi, Laurent; Falchi, Alessandra

    2014-04-01

    The 2011-2012 and 2012-2013 post-pandemic influenza outbreaks were characterized by variability in the A(H3N2) influenza viruses, resulting in low to moderate vaccine effectiveness (VE). The aim of this study was to investigate the molecular evolution and vaccine strain match of the A(H3N2) influenza viruses, having been circulated throughout the population of the French Corsica Island in 2011-2012 and again in 2012-2013. Clinical samples from 31 patients with confirmed A(H3N2) influenza viruses were collected by general practitioners (GPs) over these two consecutive seasons. An analysis of genetic distance and antigenic drift was conducted. Based on a hemagglutinin (HA) aminoacid sequence analysis, the Corsican A(H3N2) viruses fell into the A/Victoria/208/2009 genetic clade, group 3. All influenza viruses were characterized by at least four fixed amino acid mutations which were: N145S (epitope A); Q156H and V186G (epitope B) Y219S (epitope D), with respect to the A/Perth/16/2009 (reference vaccine strain for the 2011-2012) and the A/Victoria/361/2011 (reference vaccine strain for the 2012-2013). Using the p(epitope) model, the percentages of the perfect match VE estimated against circulated strains declined within and between seasons, with estimations of <50%. Overall, these results seem to indicate an antigenic drift of the A(H3N2) influenza viruses which were circulated in Corsica. These findings highlight the importance of the continuous and careful surveillance of genetic changes in the HA domain during seasonal influenza epidemics, in order to provide information on newly emerging genetic variants. © 2013 Wiley Periodicals, Inc.

  11. Virologic Differences Do Not Fully Explain the Diversification of Swine Influenza Viruses in the United States

    PubMed Central

    Sun, Yilun; Yoon, Sun-Woo; Jeevan, Trushar; Dlugolenski, Daniel; Tripp, Ralph A.; Tang, Li

    2016-01-01

    ABSTRACT Influenza A(H1N1) viruses entered the U.S. swine population following the 1918 pandemic and remained genetically stable for roughly 80 years. In 1998, there was an outbreak of influenza-like illness among swine that was caused by A(H3N2) viruses containing the triple reassortant internal gene (TRIG) cassette. Following the TRIG cassette emergence, numerous reassortant viruses were isolated in nature, suggesting that the TRIG virus had an enhanced ability to reassort compared to the classical swine virus. The present study was designed to quantify the relative reassortment capacities of classical and TRIG swine viruses. Reverse genetic viruses were generated from the classical H1N1 virus A/swine/MN/37866/1999 (MN/99), the TRIG virus A/swine/NC/18161/2002 (NC/02), and a seasonal human H3N2 virus, A/TX/6/1996 (TX/96), to measure in vitro reassortment and growth potentials. After coinfection with NC/02 or MN/99 plus TX/96, H1/H3 double-positive cells were identified. Delayed TX/96 infection was fully excluded by both swine viruses. We then analyzed reassortant H3 viruses. Seventy-seven of 81 (95.1%) TX/96-NC/02 reassortants contained at least one polymerase gene segment from NC/02, whereas only 34 of 61 (55.7%) MN/99-TX/96 reassortants contained at least one polymerase gene segment from MN/99. Additionally, 38 of 81 (46.9%) NC/02-TX/96 reassortants contained all NC/02 polymerase gene segments, while none of the MN/99-TX/96 reassortants contained all MN/99 polymerase genes. There were 21 H3 reassortants between MN/99 and TX/96, compared to only 17 H3 reassortants between NC/02 and TX/96. Overall, the results indicate that there are no distinct differences in the ability of the TRIG to reassort with a human virus compared to the classical swine virus. IMPORTANCE There appear to be no differences in the abilities of classical swine and TRIG swine viruses to exclude a second virus, suggesting that under the right circumstances both viruses have similar

  12. Reverse zoonosis of influenza to swine: new perspectives on the human–animal interface

    USDA-ARS?s Scientific Manuscript database

    The origins of the 2009 influenza A (H1N1) pandemic in swine are unknown, highlighting gaps in our understanding of influenza A virus (IAV) ecology and evolution. We review how recently strengthened influenza virus surveillance in pigs has revealed that influenza virus transmission from humans to sw...

  13. Influenza A virus vaccines for swine.

    PubMed

    Vincent, Amy L; Perez, Daniel R; Rajao, Daniela; Anderson, Tavis K; Abente, Eugenio J; Walia, Rasna R; Lewis, Nicola S

    2017-07-01

    Economic losses due to influenza A virus (IAV) infections are substantial and a global problem, ranking among the top three major health challenges in the swine industry. Currently, H1 and H3 subtypes circulate in pigs globally associated with different combinations of N1 and N2 subtypes; however, the origin, gene constellation, and antigenic makeup of IAV vary greatly on different continents. Vaccination is one means of mitigating the effects of IAV disease, and vaccines are most effective if the strains included closely match the currently circulating strains in pigs. Genetic analyses provide panoramic views of the virus landscape at the sequence level and, thus, can aid in the selection of well-matched swine IAV vaccine strains, but is not sufficient alone. Additionally, a major challenge in selecting appropriate swine IAV vaccine strains is the co-circulation of multiple lineages of viruses in the same region, requiring multivalent or broadly cross-reacting antigens. Due to this complex IAV ecology in swine, new vaccination strategies and vaccine platforms are needed. The hemagglutinin (HA) viral protein is the major target of neutralizing antibodies, which are widely considered to be correlated with protection. Virus variants that are not recognized by previously elicited antibodies can render traditional vaccines that primarily elicit humoral responses ineffective, and therefore result in the need for vaccine strain reformulation and re-vaccination. In the future, new vaccine platforms may be on the market that will provide alternative options to those currently available. Nonetheless, a collaborative approach is needed to improve IAV vaccine strain selection for use in swine. Published by Elsevier B.V.

  14. Effect of previous and current vaccination against influenza A(H1N1)pdm09, A(H3N2), and B during the post-pandemic period 2010-2016 in Spain

    PubMed Central

    Castilla, Jesús; Pozo, Francisco

    2017-01-01

    Background Recent studies suggest that the protective effect of the current influenza vaccine could be influenced by vaccination in previous seasons. We estimated the combined effect of the previous and current influenza vaccines from the 2010–2011 season to the 2015–2016 season in Spain. Methods We performed a test-negative case-control study in patients ≥9 years old. We estimated the influenza vaccine effectiveness (IVE) against influenza A(H1N1)pdm09, A(H3N2), and B virus. Results We included 1206 influenza A(H1N1)pdm09 cases, 1358 A(H3N2) cases and 1079 B cases. IVE against A(H1N1)pdm09 virus in the pooled-season analysis was 53% (95% Confidence Interval (CI): 21% to 72%) for those vaccinated only in the current season and 50% (95%CI: 23% to 68%) for those vaccinated in the both current and previous seasons. Against the influenza A(H3N2) virus, IVE was 17% (95%CI: -43% to 52%) for those vaccinated only in the current season and 3% (95%CI: -33% to 28%) for those vaccinated in both seasons. Regarding influenza B, we obtained similar IVEs for those vaccinated only in the current and those vaccinated in both seasons: 57% (95%CI: 12% to 79%) and 56% (95%CI: 36% to 70%), respectively. Conclusion Our results suggested no interference between the previous and current influenza vaccines against A(H1N1)pdm09 and B viruses, but a possible negative interference against A(H3N2) virus. PMID:28614376

  15. Genetic Characterization and Evolution of H1N1pdm09 after Circulation in a Swine Farm

    PubMed Central

    Boni, Arianna; Vaccari, Gabriele; Di Trani, Livia; Zaccaria, Guendalina; Alborali, Giovanni Loris; Lelli, Davide; Cordioli, Paolo; Moreno, Ana Maria

    2014-01-01

    Following the emergence of the A(H1N1)pdm09 in humans, this novel influenza virus was reverse transmitted from infected people to swine population worldwide. In this study we investigated the molecular evolution of A(H1N1)pdm09 virus identified in pigs reared in a single herd. Nasal swabs taken from pigs showing respiratory distress were tested for influenza type A and A(H1N1)pdm09 by real-time RT-PCR assays. Virus isolation from positive samples was attempted by inoculation of nasal swabs samples into specific pathogen free embryonated chicken eggs (ECE) and complete genome sequencing was performed on virus strains after replication on ECE or from original swab sample. The molecular analysis of hemagglutinin (HA) showed, in four of the swine influenza viruses under study, a unique significant amino acid change, represented by a two-amino acid insertion at the HA receptor binding site. Phylogenetic analysis of HA, neuraminidase, and concatenated internal genes revealed a very similar topology, with viruses under study forming a separate cluster, branching outside the A(H1N1)pdm09 isolates recognized until 2014. The emergence of this new cluster of A(H1N1)pdm09 in swine raises further concerns about whether A(H1N1)pdm09 with new molecular characteristics will become established in pigs and potentially transmitted to humans. PMID:25025062

  16. Computationally Optimized Broadly Reactive Hemagglutinin Elicits Hemagglutination Inhibition Antibodies against a Panel of H3N2 Influenza Virus Cocirculating Variants

    PubMed Central

    Wong, Terianne M.; Allen, James D.; Bebin-Blackwell, Anne-Gaelle; Carter, Donald M.; Alefantis, Timothy; DiNapoli, Joshua; Kleanthous, Harold

    2017-01-01

    ABSTRACT Each influenza season, a set of wild-type viruses, representing one H1N1, one H3N2, and one to two influenza B isolates, are selected for inclusion in the annual seasonal influenza vaccine. In order to develop broadly reactive subtype-specific influenza vaccines, a methodology called computationally optimized broadly reactive antigens (COBRA) was used to design novel hemagglutinin (HA) vaccine immunogens. COBRA technology was effectively used to design HA immunogens that elicited antibodies that neutralized H5N1 and H1N1 isolates. In this report, the development and characterization of 17 prototype H3N2 COBRA HA proteins were screened in mice and ferrets for the elicitation of antibodies with HA inhibition (HAI) activity against human seasonal H3N2 viruses that were isolated over the last 48 years. The most effective COBRA HA vaccine regimens elicited antibodies with broader HAI activity against a panel of H3N2 viruses than wild-type H3 HA vaccines. The top leading COBRA HA candidates were tested against cocirculating variants. These variants were not efficiently detected by antibodies elicited by the wild-type HA from viruses selected as the vaccine candidates. The T-11 COBRA HA vaccine elicited antibodies with HAI and neutralization activity against all cocirculating variants from 2004 to 2007. This is the first report demonstrating broader breadth of vaccine-induced antibodies against cocirculating H3N2 strains compared to the wild-type HA antigens that were represented in commercial influenza vaccines. IMPORTANCE There is a need for an improved influenza vaccine that elicits immune responses that recognize a broader number of influenza virus strains to prevent infection and transmission. Using the COBRA approach, a set of vaccines against influenza viruses in the H3N2 subtype was tested for the ability to elicit antibodies that neutralize virus infection against not only historical vaccine strains of H3N2 but also a set of cocirculating variants that

  17. Live attenuated H5N1 vaccine with H9N2 internal genes protects chickens from infections by both Highly Pathogenic H5N1 and H9N2 Influenza Viruses

    PubMed Central

    Nang, Nguyen Tai; Song, Byung Min; Kang, Young Myong; Kim, Heui Man; Kim, Hyun Soo; Seo, Sang Heui

    2012-01-01

    Please cite this paper as: Nang et al. (2013) Live attenuated H5N1 vaccine with H9N2 internal genes protects chickens from infections by both Highly Pathogenic H5N1 and H9N2 Influenza Viruses. Influenza and Other Respiratory Viruses 7(2) 120–131. Background  The highly pathogenic H5N1 and H9N2 influenza viruses are endemic in many countries around the world and have caused considerable economic loss to the poultry industry. Objectives  We aimed to study whether a live attenuated H5N1 vaccine comprising internal genes from a cold‐adapted H9N2 influenza virus could protect chickens from infection by both H5N1 and H9N2 viruses. Methods  We developed a cold‐adapted H9N2 vaccine virus expressing hemagglutinin and neuraminidase derived from the highly pathogenic H5N1 influenza virus using reverse genetics. Results and Conclusions  Chickens immunized with the vaccine were protected from lethal infections with homologous and heterologous H5N1 or H9N2 influenza viruses. Specific antibody against H5N1 virus was detected up to 11 weeks after vaccination (the endpoint of this study). In vaccinated chickens, IgA and IgG antibody subtypes were induced in lung and intestinal tissue, and CD4+ and CD8+ T lymphocytes expressing interferon‐gamma were induced in the splenocytes. These data suggest that a live attenuated H5N1 vaccine with cold‐adapted H9N2 internal genes can protect chickens from infection with H5N1 and H9N2 influenza viruses by eliciting humoral and cellular immunity. PMID:22487301

  18. The European I-MOVE Multicentre 2013-2014 Case-Control Study. Homogeneous moderate influenza vaccine effectiveness against A(H1N1)pdm09 and heterogenous results by country against A(H3N2).

    PubMed

    Valenciano, Marta; Kissling, Esther; Reuss, Annicka; Jiménez-Jorge, Silvia; Horváth, Judit K; Donnell, Joan M O; Pitigoi, Daniela; Machado, Ausenda; Pozo, Francisco

    2015-06-04

    In the first five I-MOVE (Influenza Monitoring Vaccine Effectiveness in Europe) influenza seasons vaccine effectiveness (VE) results were relatively homogenous among participating study sites. In 2013-2014, we undertook a multicentre case-control study based on sentinel practitioner surveillance networks in six European Union (EU) countries to measure 2013-2014 influenza VE against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. Influenza A(H3N2) and A(H1N1)pdm09 viruses co-circulated during the season. Practitioners systematically selected ILI patients to swab within eight days of symptom onset. We compared cases (ILI positive to influenza A(H3N2) or A(H1N1)pdm09) to influenza negative patients. We calculated VE for the two influenza A subtypes and adjusted for potential confounders. We calculated heterogeneity between sites using the I(2) index and Cochrane's Q test. If the I(2) was <50%, we estimated pooled VE as (1 minus the OR)×100 using a one-stage model with study site as a fixed effect. If the I(2) was >49% we used a two-stage random effects model. We included in the A(H1N1)pdm09 analysis 531 cases and 1712 controls and in the A(H3N2) analysis 623 cases and 1920 controls. For A(H1N1)pdm09, the Q test (p=0.695) and the I(2) index (0%) suggested no heterogeneity of adjusted VE between study sites. Using a one-stage model, the overall pooled adjusted VE against influenza A(H1N1)pdm2009 was 47.5% (95% CI: 16.4-67.0). For A(H3N2), the I(2) was 51.5% (p=0.067). Using a two-stage model for the pooled analysis, the adjusted VE against A(H3N2) was 29.7 (95% CI: -34.4-63.2). The results suggest a moderate 2013-2014 influenza VE against A(H1N1)pdm09 and a low VE against A(H3N2). The A(H3N2) estimates were heterogeneous among study sites. Larger sample sizes by study site are needed to prevent statistical heterogeneity, decrease variability and allow for two-stage pooled VE for all subgroup analyses. Copyright © 2015 The Authors

  19. Zoonotic Risk, Pathogenesis, and Transmission of Avian-Origin H3N2 Canine Influenza Virus

    PubMed Central

    Sun, Hailiang; Blackmon, Sherry; Yang, Guohua; Waters, Kaitlyn; Li, Tao; Tangwangvivat, Ratanaporn; Xu, Yifei; Shyu, Daniel; Wen, Feng; Cooley, Jim; Senter, Lucy; Lin, Xiaoxu; Jarman, Richard; Hanson, Larry; Webby, Richard

    2017-01-01

    ABSTRACT Two subtypes of influenza A virus (IAV), avian-origin canine influenza virus (CIV) H3N2 (CIV-H3N2) and equine-origin CIV H3N8 (CIV-H3N8), are enzootic in the canine population. Dogs have been demonstrated to seroconvert in response to diverse IAVs, and naturally occurring reassortants of CIV-H3N2 and the 2009 H1N1 pandemic virus (pdmH1N1) have been isolated. We conducted a thorough phenotypic evaluation of CIV-H3N2 in order to assess its threat to human health. Using ferret-generated antiserum, we determined that CIV-H3N2 is antigenically distinct from contemporary human H3N2 IAVs, suggesting that there may be minimal herd immunity in humans. We assessed the public health risk of CIV-H3N2 × pandemic H1N1 (pdmH1N1) reassortants by characterizing their in vitro genetic compatibility and in vivo pathogenicity and transmissibility. Using a luciferase minigenome assay, we quantified the polymerase activity of all possible 16 ribonucleoprotein (RNP) complexes (PB2, PB1, PA, NP) between CIV-H3N2 and pdmH1N1, identifying some combinations that were more active than either parental virus complex. Using reverse genetics and fixing the CIV-H3N2 hemagglutinin (HA), we found that 51 of the 127 possible reassortant viruses were viable and able to be rescued. Nineteen of these reassortant viruses had high-growth phenotypes in vitro, and 13 of these replicated in mouse lungs. A single reassortant with the NP and HA gene segments from CIV-H3N2 was selected for characterization in ferrets. The reassortant was efficiently transmitted by contact but not by the airborne route and was pathogenic in ferrets. Our results suggest that CIV-H3N2 reassortants may pose a moderate risk to public health and that the canine host should be monitored for emerging IAVs. IMPORTANCE IAV pandemics are caused by the introduction of novel viruses that are capable of efficient and sustained transmission into a human population with limited herd immunity. Dogs are a a potential mixing vessel for

  20. Zoonotic Risk, Pathogenesis, and Transmission of Avian-Origin H3N2 Canine Influenza Virus.

    PubMed

    Sun, Hailiang; Blackmon, Sherry; Yang, Guohua; Waters, Kaitlyn; Li, Tao; Tangwangvivat, Ratanaporn; Xu, Yifei; Shyu, Daniel; Wen, Feng; Cooley, Jim; Senter, Lucy; Lin, Xiaoxu; Jarman, Richard; Hanson, Larry; Webby, Richard; Wan, Xiu-Feng

    2017-11-01

    Two subtypes of influenza A virus (IAV), avian-origin canine influenza virus (CIV) H3N2 (CIV-H3N2) and equine-origin CIV H3N8 (CIV-H3N8), are enzootic in the canine population. Dogs have been demonstrated to seroconvert in response to diverse IAVs, and naturally occurring reassortants of CIV-H3N2 and the 2009 H1N1 pandemic virus (pdmH1N1) have been isolated. We conducted a thorough phenotypic evaluation of CIV-H3N2 in order to assess its threat to human health. Using ferret-generated antiserum, we determined that CIV-H3N2 is antigenically distinct from contemporary human H3N2 IAVs, suggesting that there may be minimal herd immunity in humans. We assessed the public health risk of CIV-H3N2 × pandemic H1N1 (pdmH1N1) reassortants by characterizing their in vitro genetic compatibility and in vivo pathogenicity and transmissibility. Using a luciferase minigenome assay, we quantified the polymerase activity of all possible 16 ribonucleoprotein (RNP) complexes (PB2, PB1, PA, NP) between CIV-H3N2 and pdmH1N1, identifying some combinations that were more active than either parental virus complex. Using reverse genetics and fixing the CIV-H3N2 hemagglutinin (HA), we found that 51 of the 127 possible reassortant viruses were viable and able to be rescued. Nineteen of these reassortant viruses had high-growth phenotypes in vitro , and 13 of these replicated in mouse lungs. A single reassortant with the NP and HA gene segments from CIV-H3N2 was selected for characterization in ferrets. The reassortant was efficiently transmitted by contact but not by the airborne route and was pathogenic in ferrets. Our results suggest that CIV-H3N2 reassortants may pose a moderate risk to public health and that the canine host should be monitored for emerging IAVs. IMPORTANCE IAV pandemics are caused by the introduction of novel viruses that are capable of efficient and sustained transmission into a human population with limited herd immunity. Dogs are a a potential mixing vessel for avian

  1. Neutralizing Antibody Responses to Antigenically Drifted Influenza A(H3N2) Viruses among Children and Adolescents following 2014-2015 Inactivated and Live Attenuated Influenza Vaccination

    PubMed Central

    Martin, Judith M.; Gross, F. Liaini; Jefferson, Stacie; Cole, Kelly Stefano; Archibald, Crystal Ann; Nowalk, Mary Patricia; Susick, Michael; Moehling, Krissy; Spencer, Sarah; Chung, Jessie R.; Flannery, Brendan; Zimmerman, Richard K.

    2016-01-01

    Human influenza A(H3N2) viruses that predominated during the moderately severe 2014-2015 influenza season differed antigenically from the vaccine component, resulting in reduced vaccine effectiveness (VE). To examine antibody responses to 2014-2015 inactivated influenza vaccine (IIV) and live-attenuated influenza vaccine (LAIV) among children and adolescents, we collected sera before and after vaccination from 150 children aged 3 to 17 years enrolled at health care facilities. Hemagglutination inhibition (HI) assays were used to assess the antibody responses to vaccine strains. We evaluated cross-reactive antibody responses against two representative A(H3N2) viruses that had antigenically drifted from the A(H3N2) vaccine component using microneutralization (MN) assays. Postvaccination antibody titers to drifted A(H3N2) viruses were higher following receipt of IIV (MN geometric mean titers [GMTs], 63 to 68; 38 to 45% achieved seroconversion) versus LAIV (MN GMT, 22; only 3 to 5% achieved seroconversion). In 9- to 17-year-olds, the highest MN titers were observed among IIV-vaccinated individuals who had received LAIV in the previous season. Among all IIV recipients aged 3 to 17 years, the strongest predictor of antibody responses to the drifted viruses was the prevaccination titers to the vaccine strain. The results of our study suggest that in an antigenically drifted influenza season, vaccination still induced cross-reactive antibody responses to drifted circulating A(H3N2) viruses, although higher antibody titers may be required for protection. Antibody responses to drifted A(H3N2) viruses following vaccination were influenced by multiple factors, including vaccine type and preexisting immunity from prior exposure. PMID:27558294

  2. Swine influenza virus: zoonotic potential and vaccination strategies for the control of avian and swine influenzas.

    PubMed

    Thacker, Eileen; Janke, Bruce

    2008-02-15

    Influenza viruses are able to infect humans, swine, and avian species, and swine have long been considered a potential source of new influenza viruses that can infect humans. Swine have receptors to which both avian and mammalian influenza viruses bind, which increases the potential for viruses to exchange genetic sequences and produce new reassortant viruses in swine. A number of genetically diverse viruses are circulating in swine herds throughout the world and are a major cause of concern to the swine industry. Control of swine influenza is primarily through the vaccination of sows, to protect young pigs through maternally derived antibodies. However, influenza viruses continue to circulate in pigs after the decay of maternal antibodies, providing a continuing source of virus on a herd basis. Measures to control avian influenza in commercial poultry operations are dictated by the virulence of the virus. Detection of a highly pathogenic avian influenza (HPAI) virus results in immediate elimination of the flock. Low-pathogenic avian influenza viruses are controlled through vaccination, which is done primarily in turkey flocks. Maintenance of the current HPAI virus-free status of poultry in the United States is through constant surveillance of poultry flocks. Although current influenza vaccines for poultry and swine are inactivated and adjuvanted, ongoing research into the development of newer vaccines, such as DNA, live-virus, or vectored vaccines, is being done. Control of influenza virus infection in poultry and swine is critical to the reduction of potential cross-species adaptation and spread of influenza viruses, which will minimize the risk of animals being the source of the next pandemic.

  3. Experimental infection and natural contact exposure of ferrets with canine influenza virus (H3N2).

    PubMed

    Lee, Yu-Na; Lee, Dong-Hun; Park, Jae-Keun; Yuk, Seong-Su; Kwon, Jung-Hoon; Nahm, Sang-Soep; Lee, Joong-Bok; Park, Seung-Yong; Choi, In-Soo; Song, Chang-Seon

    2013-02-01

    Epidemics of H3N2 canine influenza virus (CIV) among dogs in South Korea and southern China have raised concern over the potential for zoonotic transmission of these viruses. Here, we analysed the pathogenesis and transmissibility of H3N2 CIV in ferret. H3N2 CIV replicated efficiently in the respiratory system of inoculated ferrets and caused acute necrotizing bronchioalveolitis and non-suppurative encephalitis. Transmission of H3N2 CIV was detected in three of six ferrets co-housed with inoculated ferrets, but no viruses were detected in second-contact ferrets. These findings show that H3N2 CIV has the capacity to replicate in and transmit partially among co-housed ferrets and underscore the need for continued public health surveillance.

  4. Respiratory Highlights, 2016 - 2017 Influenza Season (2 October 2016 - 31 September 2017)

    DTIC Science & Technology

    2018-02-21

    influenza from an infected child with a history of swine contact at an agricultural event in Texas. The HA gene from select influenza positives was...Texas. Further investigation revealed that the child had attended an agricultural event with her family and was in contact with a swine litter. No...receptor binding site.2,5 Figure 5. A single influenza A(H3N2)v was identified at USAFSAM from a child in Texas who had attended an agricultural event

  5. [Susceptibility of human influenza A (H3N2) viruses to neuraminidase inhibitors isolated during 2011-2012 in China].

    PubMed

    Huang, Weijuan; Tan, Minju; Zhao, Xiang; Cheng, Yanhui; Li, Xiyan; Guo, Junfeng; Wei, Hejiang; Xiao, Ning; Wang, Zhao; Wang, Dayan; Shu, Yuelong

    2015-06-01

    To analyze the susceptibility of influenza A (H3N2) viruses to neuraminidase inhibitors during 2011-2012 in Mainland China. All the tested viruses were obtained from the Chinese National Influenza Surveillance Network, which covers 31 provinces in mainland China, including 408 network laboratories and 554 sentinel hospitals. In total 1 903 viruses were selected with isolation date from January 1, 2011 to December 31, 2012 in Mainland China, among these viruses, 721 were confirmed to be influenza A (H3N2) virus by Chinese National Influenza Center and tested for the susceptibility to oseltamivir and zanamivir using chemiluminescence-based assay. The neuraminidase inhibitor sensitive reference virus A/Washington/01/2007 (119E) and oseltamivir resistant virus A/Texas/12/2007 (E119V) were used as control in this study. The t -test was used to compare the difference of NAI susceptibility of viruses isolated from different years. The half maximal inhibitory concentration (IC₅₀) of A/Washington/01/2007 for oseltamivir and zanamivir was (0.10 ± 0.02) and (0.30 ± 0.05) nmol/L, respectively. The IC₅₀ of A/Texas/12/2007 for oseltamivir and zanamivir was (4.27 ± 1.60) and (0.20 ± 0.03) nmol/L, respectively. Among the 721 influenza A (H3N2) viruses, 132 influenza A (H3N2) viruses were isolated in 2011 and 589 influenza A (H3N2) viruses were isolated in 2012. The IC50 for oseltamivir ranged from 0.04 to 0.62 nmol/L for viruses isolated in 2011 and ranged from 0.02 to 0.95 nmol/L for viruses in 2012, and the IC₅₀ of all the viruses tested was within 10-fold IC₅₀ (1.0 nmol/L) of the neuraminidase inhibitor sensitive reference virus A/Washington/01/2007. The IC50 of zanamivir ranged from 0.12 to 0.80 nmol/L for viruses in 2011 and ranged from 0.04 to 0.72 nmol/L for viruses in 2012, and was within 10-fold IC₅₀ (3.0 nmol/L) of the neuraminidase inhibitor sensitive reference virus A/Washington/01/2007. The influenza A(H3N2) viruses isolated during 2011-2012 in

  6. Association between nasal shedding and fever that influenza A (H3N2) induces in dogs.

    PubMed

    Song, Daesub; Moon, Hyoungjoon; Jung, Kwonil; Yeom, Minjoo; Kim, Hyekwon; Han, Sangyoon; An, Dongjun; Oh, Jinsik; Kim, Jongman; Park, Bongkyun; Kang, Bokyu

    2011-01-05

    Avian origin canine influenza virus was reported in Korea. The dog to dog contact transmission of the avian origin canine influenza virus (CIV) H3N2 and CIV H3N8 was shown by experimental contact transmission. This study was focused on viral excretion and fever in order to elucidate the epidemiological associations which might be helpful to control the disease transmissions in CIV outbreak in dogs. An influenza seronegative 10-week-old Beagle dog was experimentally inoculated with the canine influenza virus A/canine/01/2007, subtype H3N2. Eight hours after inoculation, the infected dog was cohoused with seven uninfected Beagle dogs. Clinical signs including fever were recorded for 14 days post inoculation. The infected dog and four of seven contact dogs in the study showed clinical signs (sneezing, nasal discharge and coughing) during the study. Viral shedding occurred in all of the animals tested and began on 1 to 6 DPI in dogs with clinical signs. Elevated body temperatures above 39.5 °C (geometric mean temperature of 39.86 °C ± 0.49) were observed in all symptomatic dogs. The mean viral titer during fever was 2.99 log EID₅₀/ml, which was significantly higher than the viral titer detected in the non fever. The data show that contact dogs with a canine influenza infected dog shed different levels of virus in their nasal excretions and demonstrate that clinical signs, including fever, significantly correlate with the viral shedding.

  7. Seasonal H3N2 and 2009 Pandemic H1N1 Influenza A Viruses Reassort Efficiently but Produce Attenuated Progeny

    PubMed Central

    Phipps, Kara L.; Marshall, Nicolle; Tao, Hui; Danzy, Shamika; Onuoha, Nina; Steel, John

    2017-01-01

    ABSTRACT Reassortment of gene segments between coinfecting influenza A viruses (IAVs) facilitates viral diversification and has a significant epidemiological impact on seasonal and pandemic influenza. Since 1977, human IAVs of H1N1 and H3N2 subtypes have cocirculated with relatively few documented cases of reassortment. We evaluated the potential for viruses of the 2009 pandemic H1N1 (pH1N1) and seasonal H3N2 lineages to reassort under experimental conditions. Results of heterologous coinfections with pH1N1 and H3N2 viruses were compared to those obtained following coinfection with homologous, genetically tagged, pH1N1 viruses as a control. High genotype diversity was observed among progeny of both coinfections; however, diversity was more limited following heterologous coinfection. Pairwise analysis of genotype patterns revealed that homologous reassortment was random while heterologous reassortment was characterized by specific biases. pH1N1/H3N2 reassortant genotypes produced under single-cycle coinfection conditions showed a strong preference for homologous PB2-PA combinations and general preferences for the H3N2 NA, pH1N1 M, and H3N2 PB2 except when paired with the pH1N1 PA or NP. Multicycle coinfection results corroborated these findings and revealed an additional preference for the H3N2 HA. Segment compatibility was further investigated by measuring chimeric polymerase activity and growth of selected reassortants in human tracheobronchial epithelial cells. In guinea pigs inoculated with a mixture of viruses, parental H3N2 viruses dominated but reassortants also infected and transmitted to cage mates. Taken together, our results indicate that strong intrinsic barriers to reassortment between seasonal H3N2 and pH1N1 viruses are few but that the reassortants formed are attenuated relative to parental strains. IMPORTANCE The genome of IAV is relatively simple, comprising eight RNA segments, each of which typically encodes one or two proteins. Each viral protein

  8. Virological Surveillance of Influenza A Subtypes Isolated in 2014 from Clinical Outbreaks in Canadian Swine

    PubMed Central

    Grgić, Helena; Gallant, Jackie; Poljak, Zvonimir

    2017-01-01

    Influenza A viruses (IAVs) are respiratory pathogens associated with an acute respiratory disease that occurs year-round in swine production. It is currently one of the most important pathogens in swine populations, with the potential to infect other host species including humans. Ongoing research indicates that the three major subtypes of IAV—H1N1, H1N2, and H3N2—continue to expand in their genetic and antigenic diversity. In this study, we conducted a comprehensive genomic analysis of 16 IAVs isolated from different clinical outbreaks in Alberta, Manitoba, Ontario, and Saskatchewan in 2014. We also examined the genetic basis for probable antigenic differences among sequenced viruses. On the basis of phylogenetic analysis, all 13 Canadian H3N2 viruses belonged to cluster IV, eight H3N2 viruses were part of the IV-C cluster, and one virus belonged to the IV-B and one to the IV-D cluster. Based on standards used in this study, three H3N2 viruses could not be clearly classified into any currently established group within cluster IV (A to F). Three H1N2 viruses were part of the H1α cluster. PMID:28335552

  9. Origin, distribution, and potential risk factors associated with influenza A virus in swine in two production systems in Guatemala.

    PubMed

    Gonzalez-Reiche, Ana S; Ramírez, Ana L; Müller, María L; Orellana, David; Sosa, Silvia M; Ola, Pablo; Paniagua, Jorge; Ortíz, Lucía; Hernandez, Jorge; Cordón-Rosales, Celia; Perez, Daniel R

    2017-03-01

    Guatemala is the country with the largest swine production in Central America; however, evidence of influenza A virus (IAV) in pigs has not been clearly delineated. In this study, we analyzed the presence and spatial distribution of IAV in commercial and backyard swine populations. Samples from two nationwide surveys conducted in 2010 and 2011 were tested using virological (rRT-PCR and virus isolation) and serological (ELISA and hemagglutination inhibition) assays to detect IAV. Influenza A virus was detected in 15.7% of the sampled pigs (30.6% of herds) in 2010 and in 11.7% (24.2% of herds) in 2011. The percentage of seropositive pigs was 10.6% (16.1% of herds) and 1.4% (3.1% of herds) for each year, respectively. Three pandemic H1N1 and one seasonal human-like H3N2 viruses were isolated. Antibodies against viruses from different genetic clusters were detected. No reassortant strains with swine viruses were detected. The H3N2 virus was closely related to human viruses that circulated in Central America in 2010, distinct to the most recent human seasonal vaccine lineages. Spatial clusters of rRT-PCR positive herds were detected each year by scan statistics. Our results demonstrate circulation of IAV throughout Guatemala and identify commercial farms, animal health status, and age as potential risk factors associated with IAV infection and exposure. Detection of human-origin viruses in pigs suggests a role for humans in the molecular epidemiology of IAV in swine in Guatemala and evidences gaps in local animal and human surveillance. © 2016 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  10. THE SWINE LUNGWORM AS A RESERVOIR AND INTERMEDIATE HOST FOR SWINE INFLUENZA VIRUS

    PubMed Central

    Shope, Richard E.

    1941-01-01

    Multiple intramuscular injections of H. influenzae suis were found to precipitate swine influenza virus infections in a group of apparently normal swine. The most likely explanation of the phenomenon seemed to be that the animals, though healthy and susceptible, harbored the virus in some unknown manner. The factors possibly determining the phenomenon were explored experimentally but without success. PMID:19871114

  11. Highly Pathogenic Avian Influenza H5N1 Clade 2.3.2.1c Virus in Lebanon, 2016.

    PubMed

    El Romeh, Ali; Zecchin, Bianca; Fusaro, Alice; Ibrahim, Elias; El Bazzal, Bassel; El Hage, Jeanne; Milani, Adelaide; Zamperin, Gianpiero; Monne, Isabella

    2017-06-01

    We report the phylogenetic analysis of the first outbreak of H5N1 highly pathogenic avian influenza virus detected in Lebanon from poultry in April 2016. Our whole-genome sequencing analysis revealed that the Lebanese H5N1 virus belongs to genetic clade 2.3.2.1c and clusters with viruses from Europe and West Africa.

  12. Serological and molecular prevalence of swine influenza virus on farms in northwestern Mexico.

    PubMed

    López-Robles, Guadalupe; Montalvo-Corral, Maricela; Burgara-Estrella, Alexel; Hernández, Jesús

    2014-08-06

    The aim of this study was to provide an overview of the epidemiological status of swine influenza viruses in pigs from northwestern Mexico in 2008-2009. A serological and molecular survey was conducted in 150 pigs from 15 commercial farms in Sonora, Mexico (northwestern region of Mexico). The serological data showed that 55% of the sera were positive for the H1N1 subtype, 59% for the H3N2 subtype, and 38% for both subtypes. Overall, 16.6% (25/150) of the samples were positive for type A influenza by qRT-PCR. The phylogenetic analysis of the H1 viruses circulating in northwestern Mexico were grouped into cluster α, from five other clusters previously described. The influenza virus H1 circulating in northwestern Mexico showed 97-100% identity at the nucleotide level among them, 89% identity with other North American strains, 88% with strains from central Mexico, and 85% with the pandemic A/H1N1p2009 virus. Meanwhile, a closer relationship with some influenza viruses from North America (97% nucleotide identity) was found for H3 subtype. In conclusion, our results demonstrated a high circulation of strains similar to those observed in the North American linage among commercial farms in northwestern Mexico, involving of a different lineage virus different to the influenza pandemic of 2009. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Interim estimates of divergence date and vaccine strain match of human influenza A(H3N2) virus from systematic influenza surveillance (2010-2015) in Hangzhou, southeast of China.

    PubMed

    Li, Jun; Zhou, Yin-yan; Kou, Yu; Yu, Xin-fen; Zheng, Zhi-bei; Yang, Xu-hui; Wang, Hao-qiu

    2015-11-01

    In the post-pandemic period 2010-2015, seasonal influenza A(H3N2) virus predominated in Hangzhou, southeast of China, with an increased activity and semi-annual seasons. This study utilized HA virus gene segment sequences to analyze the divergence date and vaccine strain match of human influenza A(H3N2) virus from systematic influenza surveillance in Hangzhou. Virological and serological analyses of 124 representative A(H3N2) viruses from prospective studies of systematic surveillance samples were conducted to quantify the genetic and antigenic characteristics and their vaccine strain match. Bayesian phylogenetic inference showed that two separate subgroups 3C.3 and 3C.2 probably diverged from group 3C in early 2012 and then evolved into groups 3C.3a and 3C.2a, respectively, in the 2014/15 influenza season. Furthermore, high amino acid substitution rates of the HA1 subunit were found in A(H3N2) group 3C.2a variants, indicating that increased antigenic drift of A(H3N2) group 3C.2a virus is associated with a vaccine mismatch to the 2015/16 vaccine reference strain Switzerland/9715293/2013 (group 3C.3a). A portion of the group 3C.2a isolates are not covered by the current A(H3N2) vaccine strain. These findings offer insights into the emergence of group 3C.2a variants with epidemic potential in the imminent influenza seasons. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Highly pathogenic influenza H5N1 virus of clade 2.3.2.1c in Western Siberia.

    PubMed

    Marchenko, V Y; Susloparov, I M; Kolosova, N P; Goncharova, N I; Shipovalov, A V; Ilyicheva, T N; Durymanov, A G; Chernyshova, O A; Kozlovskiy, L I; Chernyshova, T V; Pryadkina, E N; Karimova, T V; Mikheev, V N; Ryzhikov, A B

    2016-06-01

    In the spring of 2015, avian influenza virus surveillance in Western Siberia resulted in isolation of several influenza H5N1 virus strains. The strains were isolated from several wild bird species. Investigation of biological features of those strains demonstrated their high pathogenicity for mammals. Phylogenetic analysis of the HA gene showed that the strains belong to clade 2.3.2.1c.

  15. A possible outbreak of swine influenza, 1892.

    PubMed

    Morens, David M; Taubenberger, Jeffery K

    2014-02-01

    Influenza A viruses are globally enzootic in swine populations. Swine influenza has been recognised only since 1918, but an anecdotal report suggests that a swine-influenza epizootic might have occurred in England in 1892, at the same time as an explosive epidemic (or pandemic recurrence) of human influenza. This outbreak suggests that the ecobiological association between human and swine influenza could extend to before 1918. By contrast with the recent documentation of swine influenza, influenza in horses has been well documented for hundreds of years, and was often linked temporally and geographically to epidemics of human influenza. Both decreased contact between people and horses, and the concomitant increase in swine production over the past century, might have altered the character and dynamics of influenza host-switch events between people and domestic mammals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. The Continuing Evolution of H5N1 and H9N2 Influenza Viruses in Bangladesh Between 2013 and 2014.

    PubMed

    Marinova-Petkova, Atanaska; Shanmuganatham, Karthik; Feeroz, Mohammed M; Jones-Engel, Lisa; Hasan, M Kamrul; Akhtar, Sharmin; Turner, Jasmine; Walker, David; Seiler, Patrick; Franks, John; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2016-05-01

    In 2011, avian influenza surveillance at the Bangladesh live bird markets (LBMs) showed complete replacement of the highly pathogenic avian influenza (HPAI) H5N1 virus of clade 2.2.2 (Qinghai-like H5N1 lineage) by the HPAI H5N1 clade 2.3.2.1. This clade, which continues to circulate in Bangladesh and neighboring countries, is an intra-and interclade reassortant; its HA, polymerase basic 1 (PB1), polymerase (PA), and nonstructural (NS) genes come from subclade 2.3.2.1a; the polymerase basic 2 (PB2) comes from subclade 2.3.2.1c; and the NA, nucleocapsid protein (NP), and matrix (M) gene from clade 2.3.4.2. The H9N2 influenza viruses cocirculating in the Bangladesh LBMs are also reassortants, possessing five genes (NS, M, NP, PA, and PB1) from an HPAI H7N3 virus previously isolated in Pakistan. Despite frequent coinfection of chickens and ducks, reassortment between these H5N1 and H9N2 viruses has been rare. However, all such reassortants detected in 2011 through 2013 have carried seven genes from the local HPAI H5N1 lineage and the PB1 gene from the Bangladeshi H9N2 clade G1 Mideast, itself derived from HPAI H7N3 virus. Although the live birds we sampled in Bangladesh showed no clinical signs of morbidity, the emergence of this reassortant HPAI H5N1 lineage further complicates endemic circulation of H5N1 viruses in Bangladesh, posing a threat to both poultry and humans.

  17. A national study of individuals who handle migratory birds for evidence of avian and swine-origin influenza virus infections.

    PubMed

    Shafir, Shira C; Fuller, Trevon; Smith, Thomas B; Rimoin, Anne W

    2012-08-01

    Persons with occupational or recreational exposure to migratory birds may be at risk for infection with highly pathogenic avian influenza and other avian influenza viruses since wild birds are the natural reservoir of influenza A. Additionally, bird handlers may host avian and swine-origin influenza (pH1N1) virus co-infections, which generate reassortant viruses with high pathogenicity in mammals. We assessed the prevalence of avian and swine influenza viruses in US-based bird handlers and estimated their exposure to different orders of wild birds including waterfowl (Anseriformes), songbirds (Passeriformes), and shorebirds (Charadriiformes). Cross-sectional serologic survey accompanied by a questionnaire to estimate behavioral risk factors. This is first survey of US-based bird handlers who also work at international sites. 401 participants were recruited and tested over the course of 3 years. One participant with occupational exposure to migratory birds had evidence of past infections with a H5N2 virus antigenically related to A/Nopi/MN/07/462960-02, which is the first case of this influenza subtype in a human host associated with exposure to wild rather than domestic birds. We detected no avian and swine-origin influenza virus co-infections. The exposure of bird handlers to songbirds was four times greater than to shorebirds or waterfowl. Though rare, the transmission of avian influenza viruses from migratory birds to US-based bird handlers has potentially significant public health and economic consequences. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. The Genomic Contributions of Avian H1N1 Influenza A Viruses to the Evolution of Mammalian Strains

    PubMed Central

    Wu, Gang; Zhang, Jinghui; Webster, Robert G.

    2015-01-01

    Among the influenza A viruses (IAVs) in wild aquatic birds, only H1, H2, and H3 subtypes have caused epidemics in humans. H1N1 viruses of avian origin have also caused 3 of 5 pandemics. To understand the reappearance of H1N1 in the context of pandemic emergence, we investigated whether avian H1N1 IAVs have contributed to the evolution of human, swine, and 2009 pandemic H1N1 IAVs. On the basis of phylogenetic analysis, we concluded that the polymerase gene segments (especially PB2 and PA) circulating in North American avian H1N1 IAVs have been reintroduced to swine multiple times, resulting in different lineages that led to the emergence of the 2009 pandemic H1N1 IAVs. Moreover, the similar topologies of hemagglutinin and nucleoprotein and neuraminidase and matrix gene segments suggest that each surface glycoprotein coevolved with an internal gene segment within the H1N1 subtype. The genotype of avian H1N1 IAVs of Charadriiformes origin isolated in 2009 differs from that of avian H1N1 IAVs of Anseriformes origin. When the antigenic sites in the hemagglutinin of all 31 North American avian H1N1 IAVs were considered, 60%-80% of the amino acids at the antigenic sites were identical to those in 1918 and/or 2009 pandemic H1N1 viruses. Thus, although the pathogenicity of avian H1N1 IAVs could not be inferred from the phylogeny due to the small dataset, the evolutionary process within the H1N1 IAV subtype suggests that the circulation of H1N1 IAVs in wild birds poses a continuous threat for future influenza pandemics in humans. PMID:26208281

  19. Prevalence of Influenza A Virus in Exhibition Swine during Arrival at Agricultural Fairs.

    PubMed

    Bliss, N; Nelson, S W; Nolting, J M; Bowman, A S

    2016-09-01

    The exhibition swine at agricultural fairs provides a critical human-swine interface that allows for the bidirectional transmission of influenza A virus (IAV). Previous IAV surveillance at the end of fairs has resulted in frequent detection of IAV-infected swine; little is known, however, about the frequency with which swine arrive at fairs already infected with IAV. We investigated the IAV prevalence among exhibition swine entering fairs to better understand the epidemiology of IAV in this unique human-swine interface. In 2014, snout wipes were collected from 3547 swine during the first day of nine agricultural exhibitions in Indiana and Ohio. Samples were screened for IAV using rRT-PCR and positive samples were inoculated into cultured cells for virus isolation. The overall IAV prevalence detected among swine arriving at exhibitions was 5.3% (188/3547) via rRT-PCR and 1.5% (53/3547) via virus isolation, with IAV being detected and recovered from swine at 5 of the 9 exhibitions. Within the fairs with IAV-positive swine, the individual exhibition IAV prevalence ranged from 0.2% (1/523) to 34.4% (144/419) using rRT-PCR and 0.2% (1/523) to 10.3% (43/419) with virus isolation. Single IAV subtypes were detected at three of the fairs but subtype diversity was detected among the pigs at two fairs as both H1N1 and H3N2 were recovered from incoming swine. At two of the exhibitions, a temporal relationship was observed between the order of the individual swine in sampling and the associated IAV rRT-PCR results, indicating the fomite transmission of IAV through common contact surfaces may occur. With the knowledge that a small proportion of swine arrive at fairs shedding IAV, resources should be directed towards preventive strategies focused on limiting transmission during fairs to protect swine and humans during exhibitions. © 2016 Blackwell Verlag GmbH.

  20. Novel Reassortant H3N2 Avian Influenza Virus Isolated from Domestic Ducks in Eastern China in 2016

    PubMed Central

    Sun, Wenqiang; Li, Jiaxin; Hu, Jiao; Jiang, Daxiu; Ge, Zhichuang; Xing, Chaonan; Wang, Xiaoquan; Gu, Min; Liu, Xiaowen; Hu, Shunlin

    2017-01-01

    ABSTRACT H3 subtype avian influenza virus (AIV) poses a great threat to public health, and so investigating its epidemiology is of great importance. A novel reassortant H3N2 AIV strain was isolated from a live poultry market in eastern China. The strain’s genes originated from H1N1, H3, and H7 AIVs. Thus, the genome information of the H3N2 isolate will help to investigate further the epidemiology of H3 subtype AIVs in China. PMID:29192070

  1. Stockpiled pre-pandemic H5N1 influenza virus vaccines with AS03 adjuvant provide cross-protection from H5N2 clade 2.3.4.4 virus challenge in ferrets

    PubMed Central

    Sun, Xiangjie; Belser, Jessica A.; Pulit-Penaloza, Joanna A.; Creager, Hannah M.; Guo, Zhu; Jefferson, Stacie N.; Liu, Feng; York, Ian A.; Stevens, James; Maines, Taronna R.; Jernigan, Daniel B.; Katz, Jacqueline M.; Levine, Min Z.; Tumpey, Terrence M.

    2018-01-01

    Avian influenza viruses, notably H5 subtype viruses, pose a continuous threat to public health due to their pandemic potential. In recent years, influenza virus H5 subtype split vaccines with novel oil-in-water emulsion based adjuvants (e.g. AS03, MF59) have been shown to be safe, immunogenic, and able to induce broad immune responses in clinical trials, providing strong scientific support for vaccine stockpiling. However, whether such vaccines can provide protection from infection with emerging, antigenically distinct clades of H5 viruses has not been adequately addressed. Here, we selected two AS03-adjuvanted H5N1 vaccines from the US national prepandemic influenza vaccine stockpile and assessed whether the 2004–05 vaccines could provide protection against a 2014 highly pathogenic avian influenza (HPAI) H5N2 virus (A/northern pintail/Washington/40964/2014), a clade 2.3.4.4 virus responsible for mass culling of poultry in North America. Ferrets received two doses of adjuvanted vaccine containing 7.5 μg of hemagglutinin (HA) from A/Vietnam/1203/2004 (clade 1) or A/Anhui/1/2005 (clade 2.3.4) virus either in a homologous or heterologous prime-boost vaccination regime. We found that both vaccination regimens elicited robust antibody responses against the 2004–05 vaccine viruses and could reduce virus-induced morbidity and viral replication in the lower respiratory tract upon heterologous challenge despite the low level of cross-reactive antibody titers to the challenge H5N2 virus. This study supports the value of existing stockpiled 2004–05 influenza H5N1 vaccines, combined with AS03-adjuvant for early use in the event of an emerging pandemic with H5N2-like clade 2.3.4.4 viruses. PMID:28554058

  2. Short communication: isolation and phylogenetic analysis of an avian-origin H3N2 canine influenza virus in dog shelter, China.

    PubMed

    Su, Shuo; Yuan, Ziguo; Chen, Jidang; Xie, Jiexiong; Li, Huatao; Huang, Zhen; Zhang, Minze; Du, Guohao; Chen, Zhongming; Tu, Liqing; Zou, Yufei; Miao, Junhao; Wang, Hui; Jia, Kun; Li, Shoujun

    2013-06-01

    A H3N2 canine influenza virus, A/canine/Guangdong/3/2011 (H3N2), was isolated from roaming dogs in rural China. Sequence and phylogenetic analysis of eight gene segments revealed that the A/canine/Guangdong/3/2011 (H3N2) was most similar to a recent H3N2 canine influenza virus isolated in cats from South Korea, which originated from an avian strain. To our knowledge, this is the first report of an avian-origin H3N2 CIV which was isolated from roaming dogs in China. The epidemiologic information provided herein suggests that continued study is required to determine if this virus could be established in the roaming dog population in rural China and pose potential threats to public health.

  3. Evaluation of protective efficacy of three novel H3N2 canine influenza vaccines.

    PubMed

    Tu, Liqing; Zhou, Pei; Li, Lutao; Li, Xiuzhen; Hu, Renjun; Jia, Kun; Sun, Lingshuang; Yuan, Ziguo; Li, Shoujun

    2017-11-17

    Canine influenza virus (CIV) has the potential risk to spread in different areas and dog types. Thus, there is a growing need to develop an effective vaccine to control CIV disease. Here, we developed three vaccine candidates: 1) a recombinant pVAX1 vector expressing H3N2 CIV hemagglutinin (pVAX1-HA); 2) a live attenuated canine adenovirus type 2 expressing H3N2 CIV hemagglutinin (rCAV2-HA); and 3) an inactivated H3N2 CIV (A/canine/Guangdong/01/2006 (H3N2)). Mice received an initial intramuscular immunization that followed two booster injections at 2 and 4 weeks post-vaccination (wpv). The splenic lymphocytes were collected to assess the immune responses at 6 wpv. The protective efficacy was evaluated by challenging H3N2 CIV after vaccination (at 6 wpv). Our results demonstrated that all three vaccine candidates elicited cytokine and antibody responses in mice. The rCAV2-HA vaccine and the inactivated vaccine generated efficient protective efficacy in mice, whereas limited protection was provided by the pVAX1-HA DNA vaccine. Therefore, both the rCAV2-HA live recombinant virus and the inactivated CIV could be used as potential novel vaccines against H3N2CIV. This study provides guidance for choosing the most appropriate vaccine for the prevention and control of CIV disease.

  4. Comparative pathology in ferrets infected with H1N1 influenza A viruses isolated from different hosts.

    PubMed

    Smith, Jennifer Humberd; Nagy, Tamas; Driskell, Elizabeth; Brooks, Paula; Tompkins, S Mark; Tripp, Ralph A

    2011-08-01

    Virus replication and pulmonary disease pathogenesis in ferrets following intranasal infection with a pandemic influenza virus strain (A/California/4/09 [CA09]), a human seasonal influenza H1N1 virus isolate (A/New Caledonia/20/99 [Ncal99]), a classical swine influenza H1N1 virus isolate (A/Swine/Iowa/15/30 [Sw30]), or an avian H1N1 virus isolate (A/Mallard/MN/A108-2355/08 [Mal08]) were compared. Nasal wash virus titers were similar for Ncal99 and Sw30, with peak virus titers of 10(5.1) 50% tissue culture infectious doses (TCID(50))/ml and 10(5.5) TCID(50)/ml occurring at day 3 postinfection (p.i.), respectively. The mean peak titer for CA09 also occurred at day 3 p.i. but was higher (10(7) TCID(50)/ml). In contrast, the peak virus titers (10(3.6) to 10(4.3) TCID(50)/ml) for Mal08 were delayed, occurring between days 5 and 7 p.i. Disease pathogenesis was characterized by microscopic lesions in the nasal turbinates and lungs of all ferrets; however, Sw30 infection was associated with severe bronchointerstitial pneumonia. The results demonstrate that although CA09 is highly transmissible in the human population and replicates well in the ferret model, it causes modest disease compared to other H1N1 viruses, particularly Sw30 infection.

  5. Comparative Pathology in Ferrets Infected with H1N1 Influenza A Viruses Isolated from Different Hosts ▿

    PubMed Central

    Smith, Jennifer Humberd; Nagy, Tamas; Driskell, Elizabeth; Brooks, Paula; Tompkins, S. Mark; Tripp, Ralph A.

    2011-01-01

    Virus replication and pulmonary disease pathogenesis in ferrets following intranasal infection with a pandemic influenza virus strain (A/California/4/09 [CA09]), a human seasonal influenza H1N1 virus isolate (A/New Caledonia/20/99 [Ncal99]), a classical swine influenza H1N1 virus isolate (A/Swine/Iowa/15/30 [Sw30]), or an avian H1N1 virus isolate (A/Mallard/MN/A108-2355/08 [Mal08]) were compared. Nasal wash virus titers were similar for Ncal99 and Sw30, with peak virus titers of 105.1 50% tissue culture infectious doses (TCID50)/ml and 105.5 TCID50/ml occurring at day 3 postinfection (p.i.), respectively. The mean peak titer for CA09 also occurred at day 3 p.i. but was higher (107 TCID50/ml). In contrast, the peak virus titers (103.6 to 104.3 TCID50/ml) for Mal08 were delayed, occurring between days 5 and 7 p.i. Disease pathogenesis was characterized by microscopic lesions in the nasal turbinates and lungs of all ferrets; however, Sw30 infection was associated with severe bronchointerstitial pneumonia. The results demonstrate that although CA09 is highly transmissible in the human population and replicates well in the ferret model, it causes modest disease compared to other H1N1 viruses, particularly Sw30 infection. PMID:21593156

  6. Acute phase protein response during subclinical infection of pigs with H1N1 swine influenza virus.

    PubMed

    Pomorska-Mól, Małgorzata; Markowska-Daniel, Iwona; Pejsak, Zygmunt

    2012-10-12

    In the present study acute phase proteins (APPs) responses in pigs after subclinical infection with H1N1 swine influenza virus (SwH1N1) were evaluated. Fourteen 5 weeks old, seronegative piglets, both sexes were used. Ten of them were infected intranasally with SwH1N1. C-reactive protein (CRP), haptoglobin (Hp), serum amyloid A (SAA) and pig major acute phase protein (Pig-MAP) concentrations in serum were measured using commercial ELISAs. No significant clinical signs were observed in any of the infected pigs, however, all infected animals developed specific antibodies against SwH1N1 and viral shedding was observed from 2 to 5 dpi. Only concentrations of Hp and SAA were significantly induced after infection, with mean maximum levels from days 1 to 2 post infection (dpi). The concentrations of CRP and Pig-MAP remained generally unchanged, however in half of infected pigs the concentration of CRP tended to increase at 1 dpi (but without statistical significance). The results of our study confirmed that monitoring of APPs may be useful for detection of subclinically infected pigs. The use of SAA or Hp and Pig-MAP may be a valuable in combination [i.e. Hp (increased concentration) and Pig-MAP (unchanged concentration)] to detect subclinically SIV infected pigs, or to identify pigs actually producing a large amount of virus. Additional studies need to be done in order to confirm these findings. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Phylogenetic relationships of the HA and NA genes between vaccine and seasonal influenza A(H3N2) strains in Korea

    PubMed Central

    Park, Sehee; Bae, Joon-Yong; Yoo, Kirim; Cheong, Hee Jin; Noh, Ji Yun; Hong, Kyung Wook; Lemey, Philippe; Vrancken, Bram; Kim, Juwon; Nam, Misun; Yun, Soo-Hyeon; Cho, Woo In; Song, Joon Young; Kim, Woo Joo; Park, Mee Sook; Song, Jin-Won; Kee, Sun-Ho; Song, Ki-Joon; Park, Man-Seong

    2017-01-01

    Seasonal influenza is caused by two influenza A subtype (H1N1 and H3N2) and two influenza B lineage (Victoria and Yamagata) viruses. Of these antigenically distinct viruses, the H3N2 virus was consistently detected in substantial proportions in Korea during the 2010/11-2013/14 seasons when compared to the other viruses and appeared responsible for the influenza-like illness rate peak during the first half of the 2011/12 season. To further scrutinize possible causes for this, we investigated the evolutionary and serological relationships between the vaccine and Korean H3N2 strains during the 2011/12 season for the main antigenic determinants of influenza viruses, the hemagglutinin (HA) and neuraminidase (NA) genes. In the 2011/12 season, when the number of H3N2 cases peaked, the majority of the Korean strains did not belong to the HA clade of A/Perth/16/2009 vaccine, and no Korean strains were of this lineage in the NA segment. In a serological assay, post-vaccinated human sera exhibited much reduced hemagglutination inhibition antibody titers against the non-vaccine clade Korean H3N2 strains. Moreover, Korean strains harbored several amino acid differences in the HA antigenic sites and in the NA with respect to vaccine lineages during this season. Of these, the HA antigenic site C residues 45 and 261 and the NA residue 81 appeared to be the signatures of positive selection. In subsequent seasons, when H3N2 cases were lower, the HA and NA genes of vaccine and Korean strains were more phylogenetically related to each other. Combined, our results provide indirect support for using phylogenetic clustering patterns of the HA and possibly also the NA genes in the selection of vaccine viruses and the assessment of vaccine effectiveness. PMID:28257427

  8. Immunogenicity and protective efficacy of an elastase-dependent live attenuated swine influenza virus vaccine administered intranasally in pigs.

    PubMed

    Masic, Aleksandar; Lu, Xinya; Li, Junwei; Mutwiri, George K; Babiuk, Lorne A; Brown, Earl G; Zhou, Yan

    2010-10-08

    Influenza A virus is an important respiratory pathogen of swine that causes significant morbidity and economic impact on the swine industry. Vaccination is the first choice for prevention and control of influenza infections. Live attenuated influenza vaccines (LAIV) are approved for use in humans and horses and their application provides broad protective immunity, however no LAIV against swine influenza virus (SIV) exists in the market. Previously we reported that an elastase-dependent mutant SIV A/Sw/Sk-R345V (R345V) derived from A/Sw/Saskatchewan/18789/02 (H1N1) (SIV/Sk02) is highly attenuated in pigs. Two intratracheal administrations of R345V induced strong cell-mediated and humoral immune responses and provided a high degree of protection to antigenically different SIV infection in pigs. Here we evaluated the immunogenicity and the protective efficacy of R345V against SIV infection by intranasal administration, the more practical route for vaccination of pigs in the field. Our data showed that intranasally administered R345V live vaccine is capable of inducing strong antigen-specific IFN-γ response from local tracheo-bronchial lymphocytes and antibody responses in serum and respiratory mucosa after two applications. Intranasal vaccination of R345V provided pigs with complete protection not only from parental wild type virus infection, but also from homologous antigenic variant A/Sw/Indiana/1726/88 (H1N1) infection. Moreover, intranasal administration of R345V conferred partial protection from heterologous subtypic H3N2 SIV infection in pigs. Thus, R345V elastase-dependent mutant SIV can serve as a live vaccine against antigenically different swine influenza viruses in pigs. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Characterization of H1N1 swine influenza viruses circulating in Canadian pigs in 2009.

    PubMed

    Nfon, Charles K; Berhane, Yohannes; Hisanaga, Tamiko; Zhang, Shunzhen; Handel, Katherine; Kehler, Helen; Labrecque, Olivia; Lewis, Nicola S; Vincent, Amy L; Copps, John; Alexandersen, Soren; Pasick, John

    2011-09-01

    The 2009 pandemic H1N1 (pH1N1), of apparent swine origin, may have evolved in pigs unnoticed because of insufficient surveillance. Consequently, the need for surveillance of influenza viruses circulating in pigs has received added attention. In this study we characterized H1N1 viruses isolated from Canadian pigs in 2009. Isolates from May 2009 were comprised of hemagglutinin and neuraminidase (NA) genes of classical SIV origin in combination with the North American triple-reassortant internal gene (TRIG) cassette, here termed contemporary SIV (conSIV) H1N1. These conSIV H1N1 viruses were contiguous with the North American αH1 cluster, which was distinct from the pH1N1 isolates that were antigenically more related to the γH1 cluster. After the initial isolation of pH1N1 from an Alberta pig farm in early May 2009, pH1N1 was found several times in Canadian pigs. These pH1N1 isolates were genetically and antigenically homogeneous. In addition, H1N1 viruses bearing seasonal human H1 and N1 genes together with the TRIG cassette and an NA encoding an oseltamivir-resistance marker were isolated from pigs. The NS gene of one of these seasonal human-like SIV (shSIV) H1N1 isolates was homologous to pH1N1 NS, implicating reassortment between the two strains. Antigenic cross-reactivity was observed between pH1N1 and conSIV but not with shSIV H1N1. In summary, although there was cocirculation of pH1N1 with conSIV and shSIV H1N1 in Canadian pigs after May 2009, there was no evidence supporting the presence of pH1N1 in pigs prior to May 2009. The possibility for further reassortants being generated exists and should be closely monitored.

  10. In Vivo Selection of H1N2 Influenza Virus Reassortants in the Ferret Model

    PubMed Central

    Angel, Matthew; Kimble, J. Brian; Pena, Lindomar; Wan, Hongquan

    2013-01-01

    Although the ferret model has been extensively used to study pathogenesis and transmission of influenza viruses, little has been done to determine whether ferrets are a good surrogate animal model to study influenza virus reassortment. It has been previously shown that the pandemic 2009 H1N1 (H1N1pdm) virus was able to transmit efficiently in ferrets. In coinfection studies with either seasonal H1N1 or H3N2 strains (H1N1s or H3N2s, respectively), the H1N1pdm virus was able to outcompete these strains and become the dominant transmissible virus. However, lack of reassortment could have been the result of differences in the cell or tissue tropism of these viruses in the ferret. To address this issue, we performed coinfection studies with recombinant influenza viruses carrying the surface genes of a seasonal H3N2 strain in the background of an H1N1pdm strain and vice versa. After serial passages in ferrets, a dominant H1N2 virus population was obtained with a constellation of gene segments, most of which, except for the neuraminidase (NA) and PB1 segments, were from the H1N1pdm strain. Our studies suggest that ferrets recapitulate influenza virus reassortment events. The H1N2 virus generated through this process resembles similar viruses that are emerging in nature, particularly in pigs. PMID:23302886

  11. Novel Reassortant H3N2 Avian Influenza Virus Isolated from Domestic Ducks in Eastern China in 2016.

    PubMed

    Sun, Wenqiang; Li, Jiaxin; Hu, Jiao; Jiang, Daxiu; Ge, Zhichuang; Xing, Chaonan; Wang, Xiaoquan; Gu, Min; Liu, Xiaowen; Hu, Shunlin; Liu, Xiufan

    2017-11-30

    H3 subtype avian influenza virus (AIV) poses a great threat to public health, and so investigating its epidemiology is of great importance. A novel reassortant H3N2 AIV strain was isolated from a live poultry market in eastern China. The strain's genes originated from H1N1, H3, and H7 AIVs. Thus, the genome information of the H3N2 isolate will help to investigate further the epidemiology of H3 subtype AIVs in China. Copyright © 2017 Sun et al.

  12. Evaluation of Influenza Virus A/H3N2 and B Vaccines on the Basis of Cross-Reactivity of Postvaccination Human Serum Antibodies against Influenza Viruses A/H3N2 and B Isolated in MDCK Cells and Embryonated Hen Eggs

    PubMed Central

    Kishida, Noriko; Fujisaki, Seiichiro; Yokoyama, Masaru; Sato, Hironori; Saito, Reiko; Ikematsu, Hideyuki; Xu, Hong; Takashita, Emi; Tashiro, Masato; Takao, Shinichi; Yano, Takuya; Suga, Tomoko; Kawakami, Chiharu; Yamamoto, Miwako; Kajiyama, Keiko; Saito, Hiroyuki; Shimada, Shin'ichi; Watanabe, Sumi; Aoki, Satomi; Taira, Katsuya; Kon, Miyako; Lin, Jih-Hui

    2012-01-01

    The vaccine strains against influenza virus A/H3N2 for the 2010-2011 season and influenza virus B for the 2009-2010 and 2010-2011 seasons in Japan are a high-growth reassortant A/Victoria/210/2009 (X-187) strain and an egg-adapted B/Brisbane/60/2008 (Victoria lineage) strain, respectively. Hemagglutination inhibition (HI) tests with postinfection ferret antisera indicated that the antisera raised against the X-187 and egg-adapted B/Brisbane/60/2008 vaccine production strains poorly inhibited recent epidemic isolates of MDCK-grown A/H3N2 and B/Victoria lineage viruses, respectively. The low reactivity of the ferret antisera may be attributable to changes in the hemagglutinin (HA) protein of production strains during egg adaptation. To evaluate the efficacy of A/H3N2 and B vaccines, the cross-reactivities of postvaccination human serum antibodies against A/H3N2 and B/Victoria lineage epidemic isolates were assessed by a comparison of the geometric mean titers (GMTs) of HI and neutralization (NT) tests. Serum antibodies elicited by the X-187 vaccine had low cross-reactivity to both MDCK- and egg-grown A/H3N2 isolates by HI test and narrow cross-reactivity by NT test in all age groups. On the other hand, the GMTs to B viruses detected by HI test were below the marginal level, so the cross-reactivity was assessed by NT test. The serum neutralizing antibodies elicited by the B/Brisbane/60/2008 vaccine reacted well with egg-grown B viruses but exhibited remarkably low reactivity to MDCK-grown B viruses. The results of these human serological studies suggest that the influenza A/H3N2 vaccine for the 2010-2011 season and B vaccine for the 2009-2010 and 2010-2011 seasons may possess insufficient efficacy and low efficacy, respectively. PMID:22492743

  13. Structural Basis of Preexisting Immunity to the 2009 H1N1 Pandemic Influenza Virus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Rui; Ekiert, Damian C.; Krause, Jens C.

    The 2009 H1N1 swine flu is the first influenza pandemic in decades. The crystal structure of the hemagglutinin from the A/California/04/2009 H1N1 virus shows that its antigenic structure, particularly within the Sa antigenic site, is extremely similar to those of human H1N1 viruses circulating early in the 20th century. The cocrystal structure of the 1918 hemagglutinin with 2D1, an antibody from a survivor of the 1918 Spanish flu that neutralizes both 1918 and 2009 H1N1 viruses, reveals an epitope that is conserved in both pandemic viruses. Thus, antigenic similarity between the 2009 and 1918-like viruses provides an explanation for themore » age-related immunity to the current influenza pandemic.« less

  14. H3N2 canine influenza virus causes severe morbidity in dogs with induction of genes related to inflammation and apoptosis

    PubMed Central

    2013-01-01

    Dogs are companion animals that live in close proximity with humans. Canine H3N2 influenza virus has been isolated from pet dogs that showed severe respiratory signs and other clinical symptoms such as fever, reduced body weight, and interstitial pneumonia. The canine H3N2 influenza virus can be highly transmissible among dogs via aerosols. When we analyzed global gene expression in the lungs of infected dogs, the genes associated with the immune response and cell death were greatly elevated. Taken together, our results suggest that canine H3N2 influenza virus can be easily transmitted among dogs, and that severe pneumonia in the infected dogs may be partially due to the elevated expression of genes related to inflammation and apoptosis. PMID:24090140

  15. Waning vaccine protection against influenza A (H3N2) illness in children and older adults during a single season.

    PubMed

    Belongia, Edward A; Sundaram, Maria E; McClure, David L; Meece, Jennifer K; Ferdinands, Jill; VanWormer, Jeffrey J

    2015-01-01

    Recent studies have suggested that vaccine-induced protection against influenza may decline within one season. We reanalyzed data from a study of influenza vaccine effectiveness to determine if time since vaccination was an independent predictor of influenza A (H3N2). Patients with acute respiratory illness were actively recruited during the 2007-2008 season. Respiratory swabs were tested for influenza, and vaccination dates were determined by a validated immunization registry. The association between influenza RT-PCR result and vaccination interval (days) was examined using multivariable logistic regression, adjusting for calendar time, age and other confounders. There were 629 vaccinated participants, including 177 influenza A (H3N2) cases and 452 test negative controls. The mean (SD) interval from vaccination to illness onset was 101.7 (25.9) days for influenza cases and 93.0 (29.9) days for controls. There was a significant association between vaccination interval and influenza result in the main effects model. The adjusted odds ratio (aOR) for influenza was 1.12 (CI 1.01, 1.26) for every 14 day increase in the vaccination interval. Age modified the association between vaccination interval and influenza (p=0.005 for interaction). Influenza was associated with increasing vaccination interval in young children and older adults, but not in adolescents or non-elderly adults. Similar results were found when calendar week of vaccine receipt was assessed as the primary exposure variable. Identification of influenza A (H3N2) was associated with increasing time since vaccination among young children and older adults during a single influenza season. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Different neuraminidase inhibitor susceptibilities of human H1N1, H1N2, and H3N2 influenza A viruses isolated in Germany from 2001 to 2005/2006.

    PubMed

    Bauer, Katja; Richter, Martina; Wutzler, Peter; Schmidtke, Michaela

    2009-04-01

    In the flu season 2005/2006 amantadine-resistant human influenza A viruses (FLUAV) of subtype H3N2 circulated in Germany. This raises questions on the neuraminidase inhibitor (NAI) susceptibility of FLUAV. To get an answer, chemiluminescence-based neuraminidase inhibition assays were performed with 51 H1N1, H1N2, and H3N2 FLUAV isolated in Germany from 2001 to 2005/2006. According to the mean IC(50) values (0.38-0.91 nM for oseltamivir and 0.76-1.13 nM for zanamivir) most H1N1 and H3N2 FLUAV were NAI-susceptible. But, about four times higher zanamivir concentrations were necessary to inhibit neuraminidase activity of H1N2 viruses. Two H1N1 isolates were less susceptible to both drugs in NA inhibition as well as virus yield reduction assays. Results from sequence analysis of viral hemagglutinin and neuraminidase genes and evolutionary analysis of N2 gene revealed (i) different subclades for N2 in H1N2 and H3N2 FLUAV that could explain the differences in zanamivir susceptibility among these viruses and (ii) specific amino acid substitutions in the neuraminidase segment of the two less NAI-susceptible H1N1 isolates. One H3N2 was isolate proved to be a mixture of a NA deletion mutant and full-length NA viruses.

  17. Comparative pathogenesis of H3N2 canine influenza virus in beagle dogs challenged by intranasal and intratracheal inoculation.

    PubMed

    Luo, Jie; Lu, Gang; Ye, Shaotang; Ou, Jiajun; Fu, Cheng; Zhang, Xin; Wang, Xiangbin; Huang, Ji; Wu, Peixin; Xu, Haibin; Wu, Liyan; Li, Shoujun

    2018-05-31

    As important companion animals, dogs may serve as intermediate hosts for transmitting influenza virus to humans. However, knowledge regarding H3N2 canine influenza virus (CIV) pathogenicity is not comprehensive, which directly affects the animal models of pathogenicity in H3N2 CIV vaccine research. Here, to assess H3N2 CIV pathogenicity, we utilized 30 ten-week-old purpose-bred beagles intratracheally or intranasally inoculated with 10 6 50 % egg-infectious dose. Intratracheal inoculation was more virulent to dogs than intranasal inoculation as shown by lung pathology score, histopathological changes, clinical symptoms, and body temperature. More intense virus replication was observed in the upper and lower respiratory tracts by intratracheal than intranasal inoculation according to nasal swabs, various organ virus titers, and antigen expression. These results may enhance the H3N2 CIV infection model, providing a more complete experimental basis for studying intrinsic H3N2 CIV pathogenic mechanism, and also serving a reference role for CIV prevention and treatment. Copyright © 2018. Published by Elsevier B.V.

  18. Molecular Surveillance of Antiviral Drug Resistance of Influenza A/H3N2 Virus in Singapore, 2009-2013

    PubMed Central

    Lee, Hong Kai; Tang, Julian Wei-Tze; Loh, Tze Ping; Hurt, Aeron C.; Oon, Lynette Lin-Ean; Koay, Evelyn Siew-Chuan

    2015-01-01

    Adamantanes and neuraminidase inhibitors (NAIs) are two classes of antiviral drugs available for the chemoprophylaxis and treatment of influenza infections. To determine the frequency of drug resistance in influenza A/H3N2 viruses in Singapore, large-scale sequencing of neuraminidase (NA) and matrix protein (MP) genes was performed directly without initial culture amplification. 241 laboratory-confirmed influenza A/H3N2 clinical samples, collected between May 2009 and November 2013 were included. In total, 229 NA (95%) and 241 MP (100%) complete sequences were obtained. Drug resistance mutations in the NA and MP genes were interpreted according to published studies. For the NAIs, a visual inspection of the aligned NA sequences revealed no known drug resistant genotypes (DRGs). For the adamantanes, the well-recognised S31N DRG was identified in all 241 MP genes. In addition, there was an increasing number of viruses carrying the combination of D93G+Y155F+D251V (since May 2013) or D93G (since March 2011) mutations in the NA gene. However, in-vitro NAI testing indicated that neither D93G+Y155F+D251V nor D93G alone conferred any changes in NAI susceptibility. Lastly, an I222T mutation in the NA gene that has previously been reported to cause oseltamivir-resistance in influenza A/H1N1/2009, B, and A/H5N1, was detected from a treatment-naïve patient. Further in-vitro NAI testing is required to confirm the effect of this mutation in A/H3N2 virus. PMID:25635767

  19. In Silico Identification of Highly Conserved Epitopes of Influenza A H1N1, H2N2, H3N2, and H5N1 with Diagnostic and Vaccination Potential

    PubMed Central

    Muñoz-Medina, José Esteban; Sánchez-Vallejo, Carlos Javier; Méndez-Tenorio, Alfonso; Monroy-Muñoz, Irma Eloísa; Angeles-Martínez, Javier; Santos Coy-Arechavaleta, Andrea; Santacruz-Tinoco, Clara Esperanza; González-Ibarra, Joaquín; Anguiano-Hernández, Yu-Mei; González-Bonilla, César Raúl; Ramón-Gallegos, Eva; Díaz-Quiñonez, José Alberto

    2015-01-01

    The unpredictable, evolutionary nature of the influenza A virus (IAV) is the primary problem when generating a vaccine and when designing diagnostic strategies; thus, it is necessary to determine the constant regions in viral proteins. In this study, we completed an in silico analysis of the reported epitopes of the 4 IAV proteins that are antigenically most significant (HA, NA, NP, and M2) in the 3 strains with the greatest world circulation in the last century (H1N1, H2N2, and H3N2) and in one of the main aviary subtypes responsible for zoonosis (H5N1). For this purpose, the HMMER program was used to align 3,016 epitopes reported in the Immune Epitope Database and Analysis Resource (IEDB) and distributed in 34,294 stored sequences in the Pfam database. Eighteen epitopes were identified: 8 in HA, 5 in NA, 3 in NP, and 2 in M2. These epitopes have remained constant since they were first identified (~91 years) and are present in strains that have circulated on 5 continents. These sites could be targets for vaccination design strategies based on epitopes and/or as markers in the implementation of diagnostic techniques. PMID:26346523

  20. Rapid acquisition adaptive amino acid substitutions involved in the virulence enhancement of an H1N2 avian influenza virus in mice.

    PubMed

    Yu, Zhijun; Sun, Weiyang; Zhang, Xinghai; Cheng, Kaihui; Zhao, Chuqi; Xia, Xianzhu; Gao, Yuwei

    2017-08-01

    Although H1N2 avian influenza virus (AIV) only infect birds, documented cases of swine infection with H1N2 influenza viruses suggest this subtype AIV may pose a potential threat to mammals. Here, we generated mouse-adapted variants of a H1N2 AIV to identify adaptive changes that increased virulence in mammals. MLD 50 of the variants were reduced >1000-fold compared to the parental virus. Variants displayed enhanced replication in vitro and in vivo, and replicate in extrapulmonary organs. These data show that enhanced replication capacity and expanded tissue tropism may increase the virulence of H1N2 AIV in mice. Sequence analysis revealed multiple amino acid substitutions in the PB2 (L134H, I647L, and D701N), HA (G228S), and M1 (D231N) proteins. These results indicate that H1N2 AIV can rapidly acquire adaptive amino acid substitutions in mammalian hosts, and these amino acid substitutions collaboratively enhance the ability of H1N2 AIV to replicate and cause severe disease in mammals. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Characterization of Viral Load, Viability and Persistence of Influenza A Virus in Air and on Surfaces of Swine Production Facilities.

    PubMed

    Neira, Victor; Rabinowitz, Peter; Rendahl, Aaron; Paccha, Blanca; Gibbs, Shawn G; Torremorell, Montserrat

    2016-01-01

    Indirect transmission of influenza A virus (IAV) in swine is poorly understood and information is lacking on levels of environmental exposure encountered by swine and people during outbreaks of IAV in swine barns. We characterized viral load, viability and persistence of IAV in air and on surfaces during outbreaks in swine barns. IAV was detected in pigs, air and surfaces from five confirmed outbreaks with 48% (47/98) of oral fluid, 38% (32/84) of pen railing and 43% (35/82) of indoor air samples testing positive by IAV RT-PCR. IAV was isolated from air and oral fluids yielding a mixture of subtypes (H1N1, H1N2 and H3N2). Detection of IAV RNA from air was sustained during the outbreaks with maximum levels estimated between 7 and 11 days from reported onset. Our results indicate that during outbreaks of IAV in swine, aerosols and surfaces in barns contain significant levels of IAV potentially representing an exposure hazard to both swine and people.

  2. Evaluation of protective efficacy of three novel H3N2 canine influenza vaccines

    PubMed Central

    Li, Lutao; Li, Xiuzhen; Hu, Renjun; Jia, Kun; Sun, Lingshuang; Yuan, Ziguo; Li, Shoujun

    2017-01-01

    Canine influenza virus (CIV) has the potential risk to spread in different areas and dog types. Thus, there is a growing need to develop an effective vaccine to control CIV disease. Here, we developed three vaccine candidates: 1) a recombinant pVAX1 vector expressing H3N2 CIV hemagglutinin (pVAX1-HA); 2) a live attenuated canine adenovirus type 2 expressing H3N2 CIV hemagglutinin (rCAV2-HA); and 3) an inactivated H3N2 CIV (A/canine/Guangdong/01/2006 (H3N2)). Mice received an initial intramuscular immunization that followed two booster injections at 2 and 4 weeks post-vaccination (wpv). The splenic lymphocytes were collected to assess the immune responses at 6 wpv. The protective efficacy was evaluated by challenging H3N2 CIV after vaccination (at 6 wpv). Our results demonstrated that all three vaccine candidates elicited cytokine and antibody responses in mice. The rCAV2-HA vaccine and the inactivated vaccine generated efficient protective efficacy in mice, whereas limited protection was provided by the pVAX1-HA DNA vaccine. Therefore, both the rCAV2-HA live recombinant virus and the inactivated CIV could be used as potential novel vaccines against H3N2CIV. This study provides guidance for choosing the most appropriate vaccine for the prevention and control of CIV disease. PMID:29228675

  3. Cross-reactivity between avian influenza A (H7N9) virus and divergent H7 subtypic- and heterosubtypic influenza A viruses.

    PubMed

    Guo, Li; Wang, Dayan; Zhou, Hongli; Wu, Chao; Gao, Xin; Xiao, Yan; Ren, Lili; Paranhos-Baccalà, Gláucia; Shu, Yuelong; Jin, Qi; Wang, Jianwei

    2016-02-24

    The number of human avian H7N9 influenza infections has been increasing in China. Understanding their antigenic and serologic relationships is crucial for developing diagnostic tools and vaccines. Here, we evaluated the cross-reactivities and neutralizing activities among H7 subtype influenza viruses and between H7N9 and heterosubtype influenza A viruses. We found strong cross-reactivities between H7N9 and divergent H7 subtypic viruses, including H7N2, H7N3, and H7N7. Antisera against H7N2, H7N3, and H7N7 could also effectively neutralize two distinct H7N9 strains. Two-way cross-reactivities exist within group 2, including H3 and H4, whereas one-way cross-reactivities were found across other groups, including H1, H10, H9, and H13. Our data indicate that the hemaglutinins from divergent H7 subtypes may facilitate the development of vaccines for distinct H7N9 infections. Moreover, serologic diagnoses for H7N9 infections need to consider possible interference from the cross-reactivity of H7N9 with other subtype influenza viruses.

  4. Incidence of adamantane resistance among influenza A (H3N2) viruses isolated worldwide from 1994 to 2005: a cause for concern.

    PubMed

    Bright, Rick A; Medina, Marie-jo; Xu, Xiyan; Perez-Oronoz, Gilda; Wallis, Teresa R; Davis, Xiaohong M; Povinelli, Laura; Cox, Nancy J; Klimov, Alexander I

    2005-10-01

    Adamantanes have been used to treat influenza A virus infections for many years. Studies have shown a low incidence of resistance to these drugs among circulating influenza viruses; however, their use is rising worldwide and drug resistance has been reported among influenza A (H5N1) viruses isolated from poultry and human beings in Asia. We sought to assess adamantane resistance among influenza A viruses isolated during the past decade from countries participating in WHO's global influenza surveillance network. We analysed data for influenza field isolates that were obtained worldwide and submitted to the WHO Collaborating Center for Influenza at the US Centers for Disease Control and Prevention between Oct 1, 1994, and Mar 31, 2005. We used pyrosequencing, confirmatory sequence analysis, and phenotypic testing to detect drug resistance among circulating influenza A H3N2 (n=6524), H1N1 (n=589), and H1N2 (n=83) viruses. More than 7000 influenza A field isolates were screened for specific aminoacid substitutions in the M2 gene known to confer drug resistance. During the decade of surveillance a significant increase in drug resistance was noted, from 0.4% in 1994-1995 to 12.3% in 2003-2004. This increase in the proportion of resistant viruses was weighted heavily by those obtained from Asia with 61% of resistant viruses isolated since 2003 being from people in Asia. Our data raise concerns about the appropriate use of adamantanes and draw attention to the importance of tracking the emergence and spread of drug-resistant influenza A viruses.

  5. Live Bird Markets of Bangladesh: H9N2 Viruses and the Near Absence of Highly Pathogenic H5N1 Influenza

    PubMed Central

    Negovetich, Nicholas J.; Feeroz, Mohammed M.; Jones-Engel, Lisa; Walker, David; Alam, S. M. Rabiul; Hasan, Kamrul; Seiler, Patrick; Ferguson, Angie; Friedman, Kim; Barman, Subrata; Franks, John; Turner, Jasmine; Krauss, Scott; Webby, Richard J.; Webster, Robert G.

    2011-01-01

    Avian influenza surveillance in Bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic H5N1 influenza. Here, the results of an active surveillance effort focusing on the live-bird markets are presented. Prevalence of influenza infection in the birds of the live bird markets is 23.0%, which is similar to that in poultry markets in other countries. Nearly all of the isolates (94%) were of the non-pathogenic H9N2 subtype, but viruses of the H1N2, H1N3, H3N6, H4N2, H5N1, and H10N7 subtypes were also observed. The highly pathogenic H5N1-subtype virus was observed at extremely low prevalence in the surveillance samples (0.08%), and we suggest that the current risk of infection for humans in the retail poultry markets in Bangladesh is negligible. However, the high prevalence of the H9 subtype and its potential for interaction with the highly pathogenic H5N1-subtype, i.e., reassortment and attenuation of host morbidity, highlight the importance of active surveillance of the poultry markets. PMID:21541296

  6. Influenza A Viruses of Swine (IAV-S) in Vietnam from 2010 to 2015: Multiple Introductions of A(H1N1)pdm09 Viruses into the Pig Population and Diversifying Genetic Constellations of Enzootic IAV-S.

    PubMed

    Takemae, Nobuhiro; Harada, Michiyo; Nguyen, Phuong Thanh; Nguyen, Tung; Nguyen, Tien Ngoc; To, Thanh Long; Nguyen, Tho Dang; Pham, Vu Phong; Le, Vu Tri; Do, Hoa Thi; Vo, Hung Van; Le, Quang Vinh Tin; Tran, Tan Minh; Nguyen, Thanh Duy; Thai, Phuong Duy; Nguyen, Dang Hoang; Le, Anh Quynh Thi; Nguyen, Diep Thi; Uchida, Yuko; Saito, Takehiko

    2017-01-01

    Active surveillance of influenza A viruses of swine (IAV-S) involving 262 farms and 10 slaughterhouses in seven provinces in northern and southern Vietnam from 2010 to 2015 yielded 388 isolates from 32 farms; these viruses were classified into H1N1, H1N2, and H3N2 subtypes. Whole-genome sequencing followed by phylogenetic analysis revealed that the isolates represented 15 genotypes, according to the genetic constellation of the eight segments. All of the H1N1 viruses were entirely A(H1N1)pdm09 viruses, whereas all of the H1N2 and H3N2 viruses were reassortants among 5 distinct ancestral viruses: H1 and H3 triple-reassortant (TR) IAV-S that originated from North American pre-2009 human seasonal H1, human seasonal H3N2, and A(H1N1)pdm09 viruses. Notably, 93% of the reassortant IAV-S retained M genes that were derived from A(H1N1)pdm09, suggesting some advantage in terms of their host adaptation. Bayesian Markov chain Monte Carlo analysis revealed that multiple introductions of A(H1N1)pdm09 and TR IAV-S into the Vietnamese pig population have driven the genetic diversity of currently circulating Vietnamese IAV-S. In addition, our results indicate that a reassortant IAV-S with human-like H3 and N2 genes and an A(H1N1)pdm09 origin M gene likely caused a human case in Ho Chi Minh City in 2010. Our current findings indicate that human-to-pig transmission as well as cocirculation of different IAV-S have contributed to diversifying the gene constellations of IAV-S in Vietnam. This comprehensive genetic characterization of 388 influenza A viruses of swine (IAV-S) isolated through active surveillance of Vietnamese pig farms from 2010 through 2015 provides molecular epidemiological insight into the genetic diversification of IAV-S in Vietnam after the emergence of A(H1N1)pdm09 viruses. Multiple reassortments among A(H1N1)pdm09 viruses and enzootic IAV-S yielded 14 genotypes, 9 of which carried novel gene combinations. The reassortants that carried M genes derived from A(H1N1

  7. Influenza A Viruses of Swine (IAV-S) in Vietnam from 2010 to 2015: Multiple Introductions of A(H1N1)pdm09 Viruses into the Pig Population and Diversifying Genetic Constellations of Enzootic IAV-S

    PubMed Central

    Takemae, Nobuhiro; Harada, Michiyo; Nguyen, Phuong Thanh; Nguyen, Tung; Nguyen, Tien Ngoc; To, Thanh Long; Nguyen, Tho Dang; Pham, Vu Phong; Le, Vu Tri; Do, Hoa Thi; Vo, Hung Van; Le, Quang Vinh Tin; Tran, Tan Minh; Nguyen, Thanh Duy; Thai, Phuong Duy; Nguyen, Dang Hoang; Le, Anh Quynh Thi; Nguyen, Diep Thi; Uchida, Yuko

    2016-01-01

    ABSTRACT Active surveillance of influenza A viruses of swine (IAV-S) involving 262 farms and 10 slaughterhouses in seven provinces in northern and southern Vietnam from 2010 to 2015 yielded 388 isolates from 32 farms; these viruses were classified into H1N1, H1N2, and H3N2 subtypes. Whole-genome sequencing followed by phylogenetic analysis revealed that the isolates represented 15 genotypes, according to the genetic constellation of the eight segments. All of the H1N1 viruses were entirely A(H1N1)pdm09 viruses, whereas all of the H1N2 and H3N2 viruses were reassortants among 5 distinct ancestral viruses: H1 and H3 triple-reassortant (TR) IAV-S that originated from North American pre-2009 human seasonal H1, human seasonal H3N2, and A(H1N1)pdm09 viruses. Notably, 93% of the reassortant IAV-S retained M genes that were derived from A(H1N1)pdm09, suggesting some advantage in terms of their host adaptation. Bayesian Markov chain Monte Carlo analysis revealed that multiple introductions of A(H1N1)pdm09 and TR IAV-S into the Vietnamese pig population have driven the genetic diversity of currently circulating Vietnamese IAV-S. In addition, our results indicate that a reassortant IAV-S with human-like H3 and N2 genes and an A(H1N1)pdm09 origin M gene likely caused a human case in Ho Chi Minh City in 2010. Our current findings indicate that human-to-pig transmission as well as cocirculation of different IAV-S have contributed to diversifying the gene constellations of IAV-S in Vietnam. IMPORTANCE This comprehensive genetic characterization of 388 influenza A viruses of swine (IAV-S) isolated through active surveillance of Vietnamese pig farms from 2010 through 2015 provides molecular epidemiological insight into the genetic diversification of IAV-S in Vietnam after the emergence of A(H1N1)pdm09 viruses. Multiple reassortments among A(H1N1)pdm09 viruses and enzootic IAV-S yielded 14 genotypes, 9 of which carried novel gene combinations. The reassortants that carried M genes

  8. Assessment of Molecular, Antigenic, and Pathological Features of Canine Influenza A(H3N2) Viruses That Emerged in the United States

    PubMed Central

    Pulit-Penaloza, Joanna A.; Simpson, Natosha; Yang, Hua; Creager, Hannah M.; Jones, Joyce; Carney, Paul; Belser, Jessica A.; Yang, Genyan; Chang, Jessie; Zeng, Hui; Thor, Sharmi; Jang, Yunho; Killian, Mary Lea; Jenkins-Moore, Melinda; Janas-Martindale, Alicia; Dubovi, Edward; Wentworth, David E.; Stevens, James; Tumpey, Terrence M.; Davis, C. Todd; Maines, Taronna R.

    2017-01-01

    Background A single subtype of canine influenza virus (CIV), A(H3N8), was circulating in the United States until a new subtype, A(H3N2), was detected in Illinois in spring 2015. Since then, this CIV has caused thousands of infections in dogs in multiple states. Methods In this study, genetic and antigenic properties of the new CIV were evaluated. In addition, structural and glycan array binding features of the recombinant hemagglutinin were determined. Replication kinetics in human airway cells and pathogenesis and transmissibility in animal models were also assessed. Results A(H3N2) CIVs maintained molecular and antigenic features related to low pathogenicity avian influenza A(H3N2) viruses and were distinct from A(H3N8) CIVs. The structural and glycan array binding profile confirmed these findings and revealed avian-like receptor-binding specificity. While replication kinetics in human airway epithelial cells was on par with that of seasonal influenza viruses, mild-to-moderate disease was observed in infected mice and ferrets, and the virus was inefficiently transmitted among cohoused ferrets. Conclusions Further adaptation is needed for A(H3N2) CIVs to present a likely threat to humans. However, the potential for coinfection of dogs and possible reassortment of human and other animal influenza A viruses presents an ongoing risk to public health. PMID:28934454

  9. Mutations during the Adaptation of H9N2 Avian Influenza Virus to the Respiratory Epithelium of Pigs Enhance Sialic Acid Binding Activity and Virulence in Mice.

    PubMed

    Yang, W; Punyadarsaniya, D; Lambertz, R L O; Lee, D C C; Liang, C H; Höper, D; Leist, S R; Hernández-Cáceres, A; Stech, J; Beer, M; Wu, C Y; Wong, C H; Schughart, K; Meng, F; Herrler, G

    2017-04-15

    The natural reservoir for influenza viruses is waterfowl, and from there they succeeded in crossing the barrier to different mammalian species. We analyzed the adaptation of avian influenza viruses to a mammalian host by passaging an H9N2 strain three times in differentiated swine airway epithelial cells. Using precision-cut slices from the porcine lung to passage the parental virus, isolates from each of the three passages (P1 to P3) were characterized by assessing growth curves and ciliostatic effects. The only difference noted was an increased growth kinetics of the P3 virus. Sequence analysis revealed four mutations: one each in the PB2 and NS1 proteins and two in the HA protein. The HA mutations, A190V and T212I, were characterized by generating recombinant viruses containing either one or both amino acid exchanges. Whereas the parental virus recognized α2,3-linked sialic acids preferentially, the HA190 mutant bound to a broad spectrum of glycans with α2,6/8/9-linked sialic acids. The HA212 mutant alone differed only slightly from the parental virus; however, the combination of both mutations (HA190+HA212) increased the binding affinity to those glycans recognized by the HA190 mutant. Remarkably, only the HA double mutant showed a significantly increased pathogenicity in mice. In contrast, none of those mutations affected the ciliary activity of the epithelial cells which is characteristic for virulent swine influenza viruses. Taken together, our results indicate that shifts in the HA receptor affinity are just an early adaptation step of avian H9N2 strains; further mutational changes may be required to become virulent for pigs. IMPORTANCE Swine play an important role in the interspecies transmission of influenza viruses. Avian influenza A viruses (IAV) of the H9N2 subtype have successfully infected hosts from different species but have not established a stable lineage. We have analyzed the adaptation of IAV-H9N2 virus to target cells of a new host by

  10. Eurasian-Origin Gene Segments Contribute to the Transmissibility, Aerosol Release, and Morphology of the 2009 Pandemic H1N1 Influenza Virus

    PubMed Central

    Lakdawala, Seema S.; Lamirande, Elaine W.; Suguitan, Amorsolo L.; Wang, Weijia; Santos, Celia P.; Vogel, Leatrice; Matsuoka, Yumiko; Lindsley, William G.; Jin, Hong; Subbarao, Kanta

    2011-01-01

    The epidemiological success of pandemic and epidemic influenza A viruses relies on the ability to transmit efficiently from person-to-person via respiratory droplets. Respiratory droplet (RD) transmission of influenza viruses requires efficient replication and release of infectious influenza particles into the air. The 2009 pandemic H1N1 (pH1N1) virus originated by reassortment of a North American triple reassortant swine (TRS) virus with a Eurasian swine virus that contributed the neuraminidase (NA) and M gene segments. Both the TRS and Eurasian swine viruses caused sporadic infections in humans, but failed to spread from person-to-person, unlike the pH1N1 virus. We evaluated the pH1N1 and its precursor viruses in a ferret model to determine the contribution of different viral gene segments on the release of influenza virus particles into the air and on the transmissibility of the pH1N1 virus. We found that the Eurasian-origin gene segments contributed to efficient RD transmission of the pH1N1 virus likely by modulating the release of influenza viral RNA-containing particles into the air. All viruses replicated well in the upper respiratory tract of infected ferrets, suggesting that factors other than viral replication are important for the release of influenza virus particles and transmission. Our studies demonstrate that the release of influenza viral RNA-containing particles into the air correlates with increased NA activity. Additionally, the pleomorphic phenotype of the pH1N1 virus is dependent upon the Eurasian-origin gene segments, suggesting a link between transmission and virus morphology. We have demonstrated that the viruses are released into exhaled air to varying degrees and a constellation of genes influences the transmissibility of the pH1N1 virus. PMID:22241979

  11. 2009 Pandemic H1N1 Influenza Virus Causes Disease and Upregulation of Genes Related to Inflammatory and Immune Responses, Cell Death, and Lipid Metabolism in Pigs▿

    PubMed Central

    Ma, Wenjun; Belisle, Sarah E.; Mosier, Derek; Li, Xi; Stigger-Rosser, Evelyn; Liu, Qinfang; Qiao, Chuanling; Elder, Jake; Webby, Richard; Katze, Michael G.; Richt, Juergen A.

    2011-01-01

    There exists limited information about whether adaptation is needed for cross-species transmission of the 2009 pandemic H1N1 influenza virus (pH1N1). Here, we compare the pathogenesis of two pH1N1 viruses, one derived from a human patient (A/CA/04/09 [CA09]) and the other from swine (A/swine/Alberta/25/2009 [Alb09]), with that of the 1918-like classical swine influenza virus (A/swine/Iowa/1930 [IA30]) in the pig model. Both pH1N1 isolates induced clinical symptoms such as coughing, sneezing, decreased activity, fever, and labored breathing in challenged pigs, but IA30 virus did not cause any clinical symptoms except fever. Although both the pH1N1 viruses and the IA30 virus caused lung lesions, the pH1N1 viruses were shed from the nasal cavities of challenged pigs whereas the IA30 virus was not. Global gene expression analysis indicated that transcriptional responses of the viruses were distinct. pH1N1-infected pigs had an upregulation of genes related to inflammatory and immune responses at day 3 postinfection that was not seen in the IA30 infection, and expression levels of genes related to cell death and lipid metabolism at day 5 postinfection were markedly different from those of IA30 infection. These results indicate that both pH1N1 isolates are more virulent due in part to differences in the host transcriptional response during acute infection. Our study also indicates that pH1N1 does not need prior adaptation to infect pigs, has a high potential to be maintained in naïve swine populations, and might reassort with currently circulating swine influenza viruses. PMID:21900171

  12. Evaluation of Three Live Attenuated H2 Pandemic Influenza Vaccine Candidates in Mice and Ferrets

    PubMed Central

    Chen, Grace L.; Lamirande, Elaine W.; Cheng, Xing; Torres-Velez, Fernando; Orandle, Marlene; Jin, Hong; Kemble, George

    2014-01-01

    ABSTRACT H2 influenza viruses have not circulated in humans since 1968, and therefore a significant portion of the population would be susceptible to infection should H2 influenza viruses reemerge. H2 influenza viruses continue to circulate in avian reservoirs worldwide, and these reservoirs are a potential source from which these viruses could emerge. Three reassortant cold-adapted (ca) H2 pandemic influenza vaccine candidates with hemagglutinin (HA) and neuraminidase (NA) genes derived from the wild-type A/Japan/305/1957 (H2N2) (Jap/57), A/mallard/6750/1978 (H2N2) (mal/78), or A/swine/MO/4296424/2006 (H2N3) (sw/06) viruses and the internal protein gene segments from the A/Ann Arbor/6/60 ca virus were generated by plasmid-based reverse genetics (Jap/57 ca, mal/78 ca, and sw/06 ca, respectively). The vaccine candidates exhibited the in vitro phenotypes of temperature sensitivity and cold adaptation and were restricted in replication in the respiratory tract of ferrets. In mice and ferrets, the vaccines elicited neutralizing antibodies and conferred protection against homologous wild-type virus challenge. Of the three candidates, the sw/06 ca vaccine elicited cross-reactive antibodies and provided significant protection against the greatest number of heterologous viruses. These observations suggest that the sw/06 ca vaccine should be further evaluated in a clinical trial as an H2 pandemic influenza vaccine candidate. IMPORTANCE Influenza pandemics arise when novel influenza viruses are introduced into a population with little prior immunity to the new virus and often result in higher rates of illness and death than annual seasonal influenza epidemics. An influenza H2 subtype virus caused a pandemic in 1957, and H2 viruses circulated in humans till 1968. H2 influenza viruses continue to circulate in birds, and the development of an H2 influenza vaccine candidate is therefore considered a priority in preparing for future pandemics. However, we cannot predict whether a

  13. Phylogenetic Diversity and Genotypical Complexity of H9N2 Influenza A Viruses Revealed by Genomic Sequence Analysis

    PubMed Central

    Dong, Guoying; Luo, Jing; Zhang, Hong; Wang, Chengmin; Duan, Mingxing; Deliberto, Thomas Jude; Nolte, Dale Louis; Ji, Guangju; He, Hongxuan

    2011-01-01

    H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing the spectrum of H9N2 influenza viruses isolated from 1966 to 2009. Our study provides a panoramic framework for better understanding the genesis and evolution of H9N2 influenza viruses, and for describing the history of H9N2 viruses circulating in diverse hosts. Panorama phylogenetic analysis of the eight viral gene segments revealed the complexity and diversity of H9N2 influenza viruses. The 571 H9N2 viral genomes were classified into 74 separate lineages, which had marked host and geographical differences in phylogeny. Panorama genotypical analysis also revealed that H9N2 viruses include at least 98 genotypes, which were further divided according to their HA lineages into seven series (A–G). Phylogenetic analysis of the internal genes showed that H9N2 viruses are closely related to H3, H4, H5, H7, H10, and H14 subtype influenza viruses. Our results indicate that H9N2 viruses have undergone extensive reassortments to generate multiple reassortants and genotypes, suggesting that the continued circulation of multiple genotypical H9N2 viruses throughout the world in diverse hosts has the potential to cause future influenza outbreaks in poultry and epidemics in humans. We propose a nomenclature system for identifying and unifying all lineages and genotypes of H9N2 influenza viruses in order to facilitate international communication on the evolution, ecology and epidemiology of H9N2 influenza viruses. PMID:21386964

  14. Whole-Genome Characterization of a Novel Human Influenza A(H1N2) Virus Variant, Brazil

    PubMed Central

    Born, Priscila Silva; Matos, Aline Rocha; Motta, Fernando Couto; Caetano, Braulia Costa; Debur, Maria do Carmo; Riediger, Irina Nastassja; Brown, David; Siqueira, Marilda M.

    2017-01-01

    We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes). PMID:27983507

  15. Whole-Genome Characterization of a Novel Human Influenza A(H1N2) Virus Variant, Brazil.

    PubMed

    Resende, Paola Cristina; Born, Priscila Silva; Matos, Aline Rocha; Motta, Fernando Couto; Caetano, Braulia Costa; Debur, Maria do Carmo; Riediger, Irina Nastassja; Brown, David; Siqueira, Marilda M

    2017-01-01

    We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes).

  16. Haemagglutinin mutations and glycosylation changes shaped the 2012/13 influenza A(H3N2) epidemic, Houston, Texas

    PubMed Central

    Stucker, K M; Schobel, S A; Olsen, R J; Hodges, H L; Lin, X; Halpin, R A; Fedorova, N; Stockwell, T B; Tovchigrechko, A; Das, S R; Wentworth, D E; Musser, J M

    2017-01-01

    While the early start and higher intensity of the 2012/13 influenza A virus (IAV) epidemic was not unprecedented, it was the first IAV epidemic season since the 2009 H1N1 influenza pandemic where the H3N2 subtype predominated. We directly sequenced the genomes of 154 H3N2 clinical specimens collected throughout the epidemic to better understand the evolution of H3N2 strains and to inform the H3N2 vaccine selection process. Phylogenetic analyses indicated that multiple co-circulating clades and continual antigenic drift in the haemagglutinin (HA) of clades 5, 3A, and 3C, with the evolution of a new 3C subgroup (3C-2012/13), were the driving causes of the epidemic. Drift variants contained HA substitutions and alterations in the potential N-linked glycosylation sites of HA. Antigenic analysis demonstrated that viruses in the emerging subclade 3C.3 and subgroup 3C-2012/13 were not well inhibited by antisera generated against the 3C.1 vaccine strains used for the 2012/13 (A/Victoria/361/2011) or 2013/14 (A/Texas/50/2012) seasons. Our data support updating the H3N2 vaccine strain to a clade 3C.2 or 3C.3-like strain or a subclade that has drifted further. They also underscore the challenges in vaccine strain selection, particularly regarding HA and neuraminidase substitutions derived during laboratory passage that may alter antigenic testing accuracy. PMID:25990233

  17. Influenza A(H1N1)pdm09 Virus among Healthy Show Pigs, United States

    PubMed Central

    Bender, Jeffrey B.; Bridges, Carolyn B.; Daly, Russell F.; Krueger, Whitney S.; Male, Michael J.; Heil, Gary L.; Friary, John A.; Derby, Robin B.; Cox, Nancy J.

    2012-01-01

    Within 5 months after the earliest detection of human influenza A(H1N1)pdm09 virus, we found molecular and culture evidence of the virus in healthy US show pigs. The mixing of humans and pigs at swine shows possibly could further the geographic and cross-species spread of influenza A viruses. PMID:22932697

  18. Experimental transmission of avian-like swine H1N1 influenza virus between immunologically naïve and vaccinated pigs.

    PubMed

    Lloyd, Lucy E; Jonczyk, Magdalena; Jervis, Carley M; Flack, Deborah J; Lyall, John; Foote, Alasdair; Mumford, Jennifer A; Brown, Ian H; Wood, James L; Elton, Debra M

    2011-09-01

    Infection of pigs with swine influenza has been studied experimentally and in the field; however, little information is available on the natural transmission of this virus in pigs. Two studies in an experimental transmission model are presented here, one in immunologically naïve and one in a combination of vaccinated and naïve pigs. To investigate the transmission of a recent 'avian-like' swine H1N1 influenza virus in naive piglets, to assess the antibody response to a commercially available vaccine and to determine the efficiency of transmission in pigs after vaccination. Transmission chains were initiated by intranasal challenge of two immunologically naïve pigs. Animals were monitored daily for clinical signs and virus shedding. Pairs of pigs were sequentially co-housed, and once virus was detected in recipients, prior donors were removed. In the vaccination study, piglets were vaccinated and circulating antibody levels were monitored by haemagglutination inhibition assay. To study transmission in vaccinates, a pair of infected immunologically naïve animals was co-housed with vaccinated recipient pigs and further pairs of vaccinates were added sequentially as above. The chain was completed by the addition of naive pigs. Transmission of the H1N1 virus was achieved through a chain of six pairs of naïve piglets and through four pairs of vaccinated animals. Transmission occurred with minimal clinical signs and, in vaccinates, at antibody levels higher than previously reported to protect against infection. © 2011 Blackwell Publishing Ltd.

  19. The genomic evolution of H1 influenza A viruses from swine detected in the United States between 2009 and 2016.

    PubMed

    Gao, Shibo; Anderson, Tavis K; Walia, Rasna R; Dorman, Karin S; Janas-Martindale, Alicia; Vincent, Amy L

    2017-08-01

    Transmission of influenza A virus (IAV) from humans to swine occurs with relative frequency and is a critical contributor to swine IAV diversity. Subsequent to the introduction of these human seasonal lineages, there is often reassortment with endemic viruses and antigenic drift. To address whether particular genome constellations contributed to viral persistence following the introduction of the 2009 H1N1 human pandemic virus to swine in the USA, we collated and analysed 616 whole genomes of swine H1 isolates. For each gene, sequences were aligned, the best-known maximum likelihood phylogeny was inferred, and each virus was assigned a clade based upon its evolutionary history. A time-scaled Bayesian approach was implemented for the haemagglutinin (HA) gene to determine the patterns of genetic diversity over time. From these analyses, we observed an increase in genome diversity across all H1 lineages and clades, with the H1-γ and H1-δ1 genetic clades containing the greatest number of unique genome patterns. We documented 74 genome patterns from 2009 to 2016, of which 3 genome patterns were consistently detected at a significantly higher level than others across the entire time period. Eight genome patterns increased significantly, while five genome patterns were shown to decline in detection over time. Viruses with genome patterns identified as persisting in the US swine population may possess a greater capacity to infect and transmit in swine. This study highlights the emerging genetic diversity of US swine IAV from 2009 to 2016, with implications for swine and public health and vaccine control efforts.

  20. Cross-reactivity between avian influenza A (H7N9) virus and divergent H7 subtypic- and heterosubtypic influenza A viruses

    PubMed Central

    Guo, Li; Wang, Dayan; Zhou, Hongli; Wu, Chao; Gao, Xin; Xiao, Yan; Ren, Lili; Paranhos-Baccalà, Gláucia; Shu, Yuelong; Jin, Qi; Wang, Jianwei

    2016-01-01

    The number of human avian H7N9 influenza infections has been increasing in China. Understanding their antigenic and serologic relationships is crucial for developing diagnostic tools and vaccines. Here, we evaluated the cross-reactivities and neutralizing activities among H7 subtype influenza viruses and between H7N9 and heterosubtype influenza A viruses. We found strong cross-reactivities between H7N9 and divergent H7 subtypic viruses, including H7N2, H7N3, and H7N7. Antisera against H7N2, H7N3, and H7N7 could also effectively neutralize two distinct H7N9 strains. Two-way cross-reactivities exist within group 2, including H3 and H4, whereas one-way cross-reactivities were found across other groups, including H1, H10, H9, and H13. Our data indicate that the hemaglutinins from divergent H7 subtypes may facilitate the development of vaccines for distinct H7N9 infections. Moreover, serologic diagnoses for H7N9 infections need to consider possible interference from the cross-reactivity of H7N9 with other subtype influenza viruses. PMID:26907865

  1. Regional patterns of genetic diversity in swine influenza A viruses in the United States from 2010 to 2016.

    PubMed

    Walia, Rasna R; Anderson, Tavis K; Vincent, Amy L

    2018-04-06

    Regular spatial and temporal analyses of the genetic diversity and evolutionary patterns of influenza A virus (IAV) in swine informs control efforts and improves animal health. Initiated in 2009, the USDA passively surveils IAV in U.S. swine, with a focus on subtyping clinical respiratory submissions, sequencing at minimum the hemagglutinin (HA) and neuraminidase (NA) genes, and sharing these data publicly. In this study, our goal was to quantify and describe regional and national patterns in the genetic diversity and evolution of IAV in U.S. swine from 2010 to 2016. A comprehensive phylogenetic and epidemiological analysis of publicly available HA and NA genes generated by the USDA surveillance system collected from January 2010 to December 2016 was conducted. The dominant subtypes and genetic clades detected during the study period were H1N1 (H1-γ/1A.3.3.3, N1-classical, 29%), H1N2 (H1-δ1/1B.2.2, N2-2002, 27%), and H3N2 (H3-IV-A, N2-2002, 15%), but many other minor clades were also maintained. Year-round circulation was observed, with a primary epidemic peak in October-November and a secondary epidemic peak in March-April. Partitioning these data into 5 spatial zones revealed that genetic diversity varied regionally and was not correlated with aggregated national patterns of HA/NA diversity. These data suggest that vaccine composition and control efforts should consider IAV diversity within swine production regions in addition to aggregated national patterns. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Modeling risk of occupational zoonotic influenza infection in swine workers.

    PubMed

    Paccha, Blanca; Jones, Rachael M; Gibbs, Shawn; Kane, Michael J; Torremorell, Montserrat; Neira-Ramirez, Victor; Rabinowitz, Peter M

    2016-08-01

    Zoonotic transmission of influenza A virus (IAV) between swine and workers in swine production facilities may play a role in the emergence of novel influenza strains with pandemic potential. Guidelines to prevent transmission of influenza to swine workers have been developed but there is a need for evidence-based decision-making about protective measures such as respiratory protection. A mathematical model was applied to estimate the risk of occupational IAV exposure to swine workers by contact and airborne transmission, and to evaluate the use of respirators to reduce transmission.  The Markov model was used to simulate the transport and exposure of workers to IAV in a swine facility. A dose-response function was used to estimate the risk of infection. This approach is similar to methods previously used to estimate the risk of infection in human health care settings. This study uses concentration of virus in air from field measurements collected during outbreaks of influenza in commercial swine facilities, and analyzed by polymerase chain reaction.  It was found that spending 25 min working in a barn during an influenza outbreak in a swine herd could be sufficient to cause zoonotic infection in a worker. However, this risk estimate was sensitive to estimates of viral infectivity to humans. Wearing an excellent fitting N95 respirator reduced this risk, but with high aerosol levels the predicted risk of infection remained high under certain assumptions.  The results of this analysis indicate that under the conditions studied, swine workers are at risk of zoonotic influenza infection. The use of an N95 respirator could reduce such risk. These findings have implications for risk assessment and preventive programs targeting swine workers. The exact level of risk remains uncertain, since our model may have overestimated the viability or infectivity of IAV. Additionally, the potential for partial immunity in swine workers associated with repeated low

  3. Swine-origin influenza a outbreak 2009 at Shinshu University, Japan.

    PubMed

    Uchida, Mitsuo; Tsukahara, Teruomi; Kaneko, Minoru; Washizuka, Shinsuke; Kawa, Shigeyuki

    2011-02-04

    A worldwide outbreak of swine flu H1N1 pandemic influenza occurred in April 2009. To determine the mechanism underlying the spread of infection, we prospectively evaluated a survey implemented at a local university. Between August 2009 and March 2010, we surveyed 3 groups of subjects: 2318 children in six schools attached to the Faculty of Education, 11424 university students, and 3344 staff members. Subjects with influenza-like symptoms who were diagnosed with swine flu at hospitals or clinics were defined as swine flu patients and asked to make a report using a standardized form. After the start of the pandemic, a total of 2002 patients (11.7%) were registered in the survey. These patients included 928 schoolchildren (40.0%), 1016 university students (8.9%), and 58 staff members (1.7%). The incidence in schoolchildren was significantly higher than in the other 2 groups (P < 0.0001) but there were no within group differences in incidence rate between males and females. During the period of the survey, three peaks of patient numbers were observed, in November 2009, December 2009, and January 2010. The first peak consisted mainly of schoolchildren, whereas the second and third peaks included many university students. Staff members did not contribute to peak formation. Among the university students, the most common suspected route of transmission was club activity. Interventions, such as closing classes, schools, and clubs, are likely to affect the epidemic curves. Schoolchildren and university students are vulnerable to swine flu, suggesting that avoidance of close contact, especially among these young people, may be effective way in controlling future severe influenza pandemics, especially at educational institutions.

  4. Towards a sane and rational approach to management of Influenza H1N1 2009.

    PubMed

    Gallaher, William R

    2009-05-07

    Beginning in March 2009, an outbreak of influenza in North America was found to be caused by a new strain of influenza virus, designated Influenza H1N1 2009, which is a reassortant of swine, avian and human influenza viruses. Over a thousand total cases were identified with the first month, chiefly in the United States and Mexico, but also involving several European countries. Actions concerning Influenza H1N1 2009 need to be based on fact and science, following recommendations of public health officials, and not fueled by political, legal or other interests. Every influenza outbreak or pandemic is unique, so the facts of each one must be studied before an appropriate response can be developed. While reports are preliminary, through the first 4 weeks of the outbreak it does not appear to be severe either in terms of the attack rate in communities or in the virulence of the virus itself. However, there are significant changes in both the hemagglutinin and neuraminidase proteins of the new virus, 27.2% and 18.2% of the amino acid sequence, from prior H1N1 isolates in 2008 and the current vaccine. Such a degree of change qualifies as an "antigenic shift", even while the virus remains in the H1N1 family of influenza viruses, and may give influenza H1N1 2009 significant pandemic potential. Perhaps balancing this shift, the novel virus retains more of the core influenza proteins from animal strains than successful human influenza viruses, and may be inhibited from its maximum potential until further reassortment or mutation better adapts it to multiplication in humans. While contact and respiratory precautions such as frequent handwashing will slow the virus through the human population, it is likely that development of a new influenza vaccine tailored to this novel Influenza H1N1 2009 strain will be essential to blunt its ultimate pandemic impact.

  5. Towards a sane and rational approach to management of Influenza H1N1 2009

    PubMed Central

    Gallaher, William R

    2009-01-01

    Beginning in March 2009, an outbreak of influenza in North America was found to be caused by a new strain of influenza virus, designated Influenza H1N1 2009, which is a reassortant of swine, avian and human influenza viruses. Over a thousand total cases were identified with the first month, chiefly in the United States and Mexico, but also involving several European countries. Actions concerning Influenza H1N1 2009 need to be based on fact and science, following recommendations of public health officials, and not fueled by political, legal or other interests. Every influenza outbreak or pandemic is unique, so the facts of each one must be studied before an appropriate response can be developed. While reports are preliminary, through the first 4 weeks of the outbreak it does not appear to be severe either in terms of the attack rate in communities or in the virulence of the virus itself. However, there are significant changes in both the hemagglutinin and neuraminidase proteins of the new virus, 27.2% and 18.2% of the amino acid sequence, from prior H1N1 isolates in 2008 and the current vaccine. Such a degree of change qualifies as an "antigenic shift", even while the virus remains in the H1N1 family of influenza viruses, and may give influenza H1N1 2009 significant pandemic potential. Perhaps balancing this shift, the novel virus retains more of the core influenza proteins from animal strains than successful human influenza viruses, and may be inhibited from its maximum potential until further reassortment or mutation better adapts it to multiplication in humans. While contact and respiratory precautions such as frequent handwashing will slow the virus through the human population, it is likely that development of a new influenza vaccine tailored to this novel Influenza H1N1 2009 strain will be essential to blunt its ultimate pandemic impact. PMID:19422701

  6. Serological comparison of antibodies to avian influenza viruses, subtypes H5N2, H6N1, H7N3 and H7N9 between poultry workers and non-poultry workers in Taiwan in 2012.

    PubMed

    Huang, S Y; Yang, J R; Lin, Y J; Yang, C H; Cheng, M C; Liu, M T; Wu, H S; Chang, F Y

    2015-10-01

    In Taiwan, avian influenza virus (AIV) subtypes H5N2, H6N1 and H7N3 have been identified in domestic poultry, and several strains of these subtypes have become endemic in poultry. To evaluate the potential of avian-to-human transmission due to occupational exposure, an exploratory analysis of AIV antibody status in poultry workers was conducted. We enrolled 670 poultry workers, including 335 live poultry vendors (LPVs), 335 poultry farmers (PFs), and 577 non-poultry workers (NPWs). Serum antibody titres against various subtypes of viruses were analysed and compared. The overall seropositivity rates in LPVs and PFs were 2·99% (10/335) and 1·79% (6/335), respectively, against H5N2; and 0·6% (2/335) and 1·19% (4/335), respectively, for H7N3 virus. Of NPWs, 0·35% (2/577) and 0·17% (1/577) were seropositive for H5N2 and H7N3, respectively. Geographical analysis revealed that poultry workers whose workplaces were near locations where H5N2 outbreaks in poultry have been reported face greater risks of being exposed to viruses that result in elevated H5N2 antibody titres. H6N1 antibodies were detected in only one PF, and no H7N9 antibodies were found in the study subjects. Subclinical infections caused by H5N2, H6N1 and H7N3 viruses were thus identified in poultry workers in Taiwan. Occupational exposure is associated with a high risk of AIV infection, and the seroprevalence of particular avian influenza strains in humans reflects the endemic strains in poultry in this region.

  7. Molecular epidemiology of H9N2 influenza viruses in Northern Europe.

    PubMed

    Lindh, Erika; Ek-Kommonen, Christine; Väänänen, Veli-Matti; Vaheri, Antti; Vapalahti, Olli; Huovilainen, Anita

    2014-08-27

    Low pathogenic avian influenza viruses are maintained in wild bird populations throughout the world. Avian influenza viruses are characterized by their efficient ability to reassort and adapt, which enables them to cross the species barrier and enhances their zoonotic potential. Influenza viruses of the H9N2 subtype appear endemic among poultry in Eurasia. They usually exist as low-pathogenic strains and circulate between wild bird populations, poultry and birds sold at live bird markets. Direct transmission of H9N2 viruses, with receptor specificities similar to human influenza strains, to pigs and humans has been reported on several occasions. H9N2 virus was first encountered in Finland in 2009, during routine screening of hunted wild waterfowl. The next year, H9N2 influenza viruses were isolated from wild birds on four occasions, including once from a farmed mallard. We have investigated the relationship between the reared and wild bird isolates by sequencing the hemagglutinin and the neuraminidase genes of the Finnish H9N2 viruses. Nucleotide sequence comparison and phylogenetic analyses indicate that H9N2 was transmitted from wild birds to reared birds in 2010, and that highly identical strains have been circulating in Europe during the last few years. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Mortality burden of the 2009 A/H1N1 influenza pandemic in France: comparison to seasonal influenza and the A/H3N2 pandemic.

    PubMed

    Lemaitre, Magali; Carrat, Fabrice; Rey, Grégoire; Miller, Mark; Simonsen, Lone; Viboud, Cécile

    2012-01-01

    The mortality burden of the 2009 A/H1N1 pandemic remains unclear in many countries due to delays in reporting of death statistics. We estimate the age- and cause-specific excess mortality impact of the pandemic in France, relative to that of other countries and past epidemic and pandemic seasons. We applied Serfling and Poisson excess mortality approaches to model weekly age- and cause-specific mortality rates from June 1969 through May 2010 in France. Indicators of influenza activity, time trends, and seasonal terms were included in the models. We also reviewed the literature for country-specific estimates of 2009 pandemic excess mortality rates to characterize geographical differences in the burden of this pandemic. The 2009 A/H1N1 pandemic was associated with 1.0 (95% Confidence Intervals (CI) 0.2-1.9) excess respiratory deaths per 100,000 population in France, compared to rates per 100,000 of 44 (95% CI 43-45) for the A/H3N2 pandemic and 2.9 (95% CI 2.3-3.7) for average inter-pandemic seasons. The 2009 A/H1N1 pandemic had a 10.6-fold higher impact than inter-pandemic seasons in people aged 5-24 years and 3.8-fold lower impact among people over 65 years. The 2009 pandemic in France had low mortality impact in most age groups, relative to past influenza seasons, except in school-age children and young adults. The historical A/H3N2 pandemic was associated with much larger mortality impact than the 2009 pandemic, across all age groups and outcomes. Our 2009 pandemic excess mortality estimates for France fall within the range of previous estimates for high-income regions. Based on the analysis of several mortality outcomes and comparison with laboratory-confirmed 2009/H1N1 deaths, we conclude that cardio-respiratory and all-cause mortality lack precision to accurately measure the impact of this pandemic in high-income settings and that use of more specific mortality outcomes is important to obtain reliable age-specific estimates.

  9. PB2-588 V promotes the mammalian adaptation of H10N8, H7N9 and H9N2 avian influenza viruses

    PubMed Central

    Xiao, Chencheng; Ma, Wenjun; Sun, Na; Huang, Lihong; Li, Yaling; Zeng, Zhaoyong; Wen, Yijun; Zhang, Zaoyue; Li, Huanan; Li, Qian; Yu, Yuandi; Zheng, Yi; Liu, Shukai; Hu, Pingsheng; Zhang, Xu; Ning, Zhangyong; Qi, Wenbao; Liao, Ming

    2016-01-01

    Human infections with avian influenza H7N9 or H10N8 viruses have been reported in China, raising concerns that they might cause human epidemics and pandemics. However, how these viruses adapt to mammalian hosts is unclear. Here we show that besides the commonly recognized viral polymerase subunit PB2 residue 627 K, other residues including 87E, 292 V, 340 K, 588 V, 648 V, and 676 M in PB2 also play critical roles in mammalian adaptation of the H10N8 virus. The avian-origin H10N8, H7N9, and H9N2 viruses harboring PB2-588 V exhibited higher polymerase activity, more efficient replication in mammalian and avian cells, and higher virulence in mice when compared to viruses with PB2-588 A. Analyses of available PB2 sequences showed that the proportion of avian H9N2 or human H7N9 influenza isolates bearing PB2-588 V has increased significantly since 2013. Taken together, our results suggest that the substitution PB2-A588V may be a new strategy for an avian influenza virus to adapt mammalian hosts. PMID:26782141

  10. Porcine mast cells infected with H1N1 influenza virus release histamine and inflammatory cytokines and chemokines.

    PubMed

    Lee, In Hong; Kim, Hyun Soo; Seo, Sang Heui

    2017-04-01

    Mast cells reside in many tissues, including the lungs, and might play a role in enhancing influenza virus infections in animals. In this study, we cultured porcine mast cells from porcine bone marrow cells with IL-3 and stem cell factor to study the infectivity and activation of the 2009 pandemic H1N1 influenza virus of swine origin. Porcine mast cells were infected with H1N1 influenza virus, without the subsequent production of infectious viruses but were activated, as indicated by the release of histamines. Inflammatory cytokine- and chemokine-encoding genes, including IL-1α, IL-6, CXCL9, CXCL10, and CXCL11, were upregulated in the infected porcine mast cells. Our results suggest that mast cells could be involved in enhancing influenza-virus-mediated disease in infected animals.

  11. Fitness of Pandemic H1N1 and Seasonal influenza A viruses during Co-infection: Evidence of competitive advantage of pandemic H1N1 influenza versus seasonal influenza.

    PubMed

    Perez, Daniel Roberto; Sorrell, Erin; Angel, Matthew; Ye, Jianqiang; Hickman, Danielle; Pena, Lindomar; Ramirez-Nieto, Gloria; Kimble, Brian; Araya, Yonas

    2009-08-24

    On June 11, 2009 the World Health Organization (WHO) declared a new H1N1 influenza pandemic. This pandemic strain is as transmissible as seasonal H1N1 and H3N2 influenza A viruses. Major concerns facing this pandemic are whether the new virus will replace, co-circulate and/or reassort with seasonal H1N1 and/or H3N2 human strains. Using the ferret model, we investigated which of these three possibilities were most likely favored. Our studies showed that the current pandemic virus is more transmissible than, and has a biological advantage over, prototypical seasonal H1 or H3 strains.

  12. THE INFECTION OF MICE WITH SWINE INFLUENZA VIRUS.

    PubMed

    Shope, R E

    1935-09-30

    The experiments confirm the earlier observation of Andrewes, Laidlaw and Smith that the swine influenza virus is pathogenic for white mice when administered intranasally. Two field strains of the swine influenza virus were found to differ in their initial pathogenicity for mice. One strain was apparently fully pathogenic even in its 1st mouse passage while the other required 2 or 3 mouse passages to acquire full virulence for this species. Both strains, however, were initially infectious for mice, without the necessity of intervening ferret passages. There is no evidence that bacteria play any significant rôle in the mouse disease though essential in that of swine, and fatal pneumonias can be produced in mice by pure virus infections. Mice surviving the virus disease are immune to reinfection for at least a month. In mice the disease is not contagious though it is notably so in swine. The virus, while regularly producing fatal pneumonias when administered intranasally to mice, appears to be completely innocuous when given subcutaneously or intraperitoneally. Prolonged serial passage of the virus in mice does not influence its infectivity or virulence for swine or ferrets. It is a stable virus so far as its infectivity is concerned, and can be transferred at will from any one of its three known susceptible hosts to any other. In discussing these facts the stability of the swine influenza virus has been contrasted with the apparent instability of freshly isolated strains of the human influenza virus. Though the mouse is an un-natural host for the virus it is, nevertheless, useful for the study of those aspects of swine influenza which have to do with the virus only.

  13. Molecular Epidemiology of Influenza A/H3N2 Viruses Circulating in Uganda

    PubMed Central

    Byarugaba, Denis K.; Ducatez, Mariette F.; Erima, Bernard; Mworozi, Edison A.; Millard, Monica; Kibuuka, Hannah; Lukwago, Luswa; Bwogi, Josephine; Kaira, Blanche B.; Mimbe, Derrick; Schnabel, David C.; Krauss, Scott; Darnell, Daniel; Webby, Richard J.; Webster, Robert G.; Wabwire-Mangen, Fred

    2011-01-01

    The increasing availability of complete influenza virus genomes is deepening our understanding of influenza evolutionary dynamics and facilitating the selection of vaccine strains. However, only one complete African influenza virus sequence is available in the public domain. Here we present a complete genome analysis of 59 influenza A/H3N2 viruses isolated from humans in Uganda during the 2008 and 2009 season. Isolates were recovered from hospital-based sentinel surveillance for influenza-like illnesses and their whole genome sequenced. The viruses circulating during these two seasons clearly differed from each other phylogenetically. They showed a slow evolution away from the 2009/10 recommended vaccine strain (A/Brisbane/10/07), instead clustering with the 2010/11 recommended vaccine strain (A/Perth/16/09) in the A/Victoria/208/09 clade, as observed in other global regions. All of the isolates carried the adamantane resistance marker S31N in the M2 gene and carried several markers of enhanced transmission; as expected, none carried any marker of neuraminidase inhibitor resistance. The hemagglutinin gene of the 2009 isolates differed from that of the 2008 isolates in antigenic sites A, B, D, and to a lesser extent, C and E indicating evidence of an early phylogenetic shift from the 2008 to 2009 viruses. The internal genes of the 2009 isolates were similar to those of one 2008 isolate, A/Uganda/MUWRP-050/2008. Another 2008 isolate had a truncated PB1-F2 protein. Whole genome sequencing can enhance surveillance of future seasonal changes in the viral genome which is crucial to ensure that selected vaccine strains are protective against the strains circulating in Eastern Africa. This data provides an important baseline for this surveillance. Overall the influenza virus activity in Uganda appears to mirror that observed in other regions of the southern hemisphere. PMID:22132146

  14. Infectivity, transmission and pathogenicity of H5 highly pathogenic avian influenza clade 2.3.4.4 (H5N8 and H5N2) United States index viruses in Pekin ducks and Chinese geese

    USDA-ARS?s Scientific Manuscript database

    In late 2014, a H5N8 highly pathogenic avian influenza (HPAI) virus, clade 2.3.4.4, spread by migratory birds into North America mixing with low pathogenicity AI viruses to produce a H5N2 HPAI virus. The H5N8 and H5N2 HPAI viruses were detected initially in wild waterfowl and backyard birds, and lat...

  15. Construction and Immunogenicity Evaluation of Recombinant Influenza A Viruses Containing Chimeric Hemagglutinin Genes Derived from Genetically Divergent Influenza A H1N1 Subtype Viruses

    PubMed Central

    McCormick, Kara; Jiang, Zhiyong; Zhu, Longchao; Lawson, Steven R.; Langenhorst, Robert; Ransburgh, Russell; Brunick, Colin; Tracy, Miranda C.; Hurtig, Heather R.; Mabee, Leah M.; Mingo, Mark; Li, Yanhua; Webby, Richard J.

    2015-01-01

    Background and Objectives Influenza A viruses cause highly contagious diseases in a variety of hosts, including humans and pigs. To develop a vaccine that can be broadly effective against genetically divergent strains of the virus, in this study we employed molecular breeding (DNA shuffling) technology to create a panel of chimeric HA genes. Methods and Results Each chimeric HA gene contained genetic elements from parental swine influenza A viruses that had a history of zoonotic transmission, and also from a 2009 pandemic virus. Each parental virus represents a major phylogenetic clade of influenza A H1N1 viruses. Nine shuffled HA constructs were initially screened for immunogenicity in mice by DNA immunization, and one chimeric HA (HA-129) was expressed on both a A/Puerto Rico/8/34 backbone with mutations associated with a live, attenuated phenotype (PR8LAIV-129) and a A/swine/Texas/4199-2/98 backbone (TX98-129). When delivered to mice, the PR8LAIV-129 induced antibodies against all four parental viruses, which was similar to the breadth of immunity observed when HA-129 was delivered as a DNA vaccine. This chimeric HA was then tested as a candidate vaccine in a nursery pig model, using inactivated TX98-129 virus as the backbone. The results demonstrate that pigs immunized with HA-129 developed antibodies against all four parental viruses, as well as additional primary swine H1N1 influenza virus field isolates. Conclusion This study established a platform for creating novel genes of influenza viruses using a molecular breeding approach, which will have important applications toward future development of broadly protective influenza virus vaccines. PMID:26061265

  16. Enhanced pneumonia and disease in pigs vaccinated with an inactivated human-like (δ-cluster) H1N2 vaccine and challenged with pandemic 2009 H1N1 influenza virus.

    PubMed

    Gauger, Phillip C; Vincent, Amy L; Loving, Crystal L; Lager, Kelly M; Janke, Bruce H; Kehrli, Marcus E; Roth, James A

    2011-03-24

    Influenza is an economically important respiratory disease affecting swine world-wide with potential zoonotic implications. Genetic reassortment and drift has resulted in genetically and antigenically distinct swine influenza viruses (SIVs). Consequently, prevention of SIV infection is challenging due to the increased rate of genetic change and a potential lack of cross-protection between vaccine strains and circulating novel isolates. This report describes a vaccine-heterologous challenge model in which pigs were administered an inactivated H1N2 vaccine with a human-like (δ-cluster) H1 six and three weeks before challenge with H1 homosubtypic, heterologous 2009 pandemic H1N1. At necropsy, macroscopic and microscopic pneumonia scores were significantly higher in the vaccinated and challenged (Vx/Ch) group compared to non-vaccinated and challenged (NVx/Ch) pigs. The Vx/Ch group also demonstrated enhanced clinical disease and a significantly elevated pro-inflammatory cytokine profile in bronchoalveolar lavage fluid compared to the NVx/Ch group. In contrast, viral shedding and replication were significantly higher in NVx/Ch pigs although all challenged pigs, including Vx/Ch pigs, were shedding virus in nasal secretions. Hemagglutination inhibition (HI) and serum neutralizing (SN) antibodies were detected to the priming antigen in the Vx/Ch pigs but no measurable cross-reacting HI or SN antibodies were detected to pandemic H1N1 (pH1N1). Overall, these results suggest that inactivated SIV vaccines may potentiate clinical signs, inflammation and pneumonia following challenge with divergent homosubtypic viruses that do not share cross-reacting HI or SN antibodies. Published by Elsevier Ltd.

  17. Case of seasonal reassortant A(H1N2) influenza virus infection, the Netherlands, March 2018.

    PubMed

    Meijer, Adam; Swaan, Corien M; Voerknecht, Martin; Jusic, Edin; van den Brink, Sharon; Wijsman, Lisa A; Voordouw, Bettie Cg; Donker, Gé A; Sleven, Jacqueline; Dorigo-Zetsma, Wendelien W; Svraka, Sanela; van Boven, Michiel; Haverkate, Manon R; Timen, Aura; van Dissel, Jaap T; Koopmans, Marion Pg; Bestebroer, Theo M; Fouchier, Ron Am

    2018-04-01

    A seasonal reassortant A(H1N2) influenza virus harbouring genome segments from seasonal influenza viruses A(H1N1)pdm09 (HA and NS) and A(H3N2) (PB2, PB1, PA, NP, NA and M) was identified in March 2018 in a 19-months-old patient with influenza-like illness (ILI) who presented to a general practitioner participating in the routine sentinel surveillance of ILI in the Netherlands. The patient recovered fully. Further epidemiological and virological investigation did not reveal additional cases.

  18. Issues encountered in development of enzyme-linked immunosorbent assay for use in detecting Influenza A virus subtype H5N1 exposure in swine.

    PubMed

    Buehler, Jason; Lager, Kelly; Vincent, Amy; Miller, Cathy; Thacker, Eileen; Janke, Bruce

    2014-03-01

    A potential mechanism by which highly pathogenic avian Influenza A virus subtype H5N1 could more readily infect human beings is through the infection of and adaptation in pigs. To detect the occurrence of such infection, monitoring of pig populations through serological screening would be highly desirable. In the current study, hemagglutination inhibition assays were able to detect antibodies against H5N1 developed in pigs, but because of antigenic variation between clades, the use of multiple virus strains were required. Whole recombinant virus and recombinant hemagglutinin antigen enzyme-linked immunosorbent assays (ELISAs) were generated that could detect antibody against multiple H5N1 strains, but which also detected antibody against endemic swine influenza viruses. A recombinant hemagglutinin antigen-based ELISA was as effective as the whole virus antigen ELISAs in detecting antibody against the H5N1 virus strains used and eliminated nearly all of the cross-reactivity with non-H5N1 virus antibody. The current study also highlighted the difficulty in establishing a decision (cutoff) value that would effectively counterbalance nonspecific reactivity against sensitivity. The results provide important information and considerations for the development of serological screening assays for highly pathogenic avian H5N1 viruses.

  19. Thromboembolic events in patients with severe pandemic influenza A/H1N1.

    PubMed

    Avnon, Lone Sølling; Munteanu, Daniela; Smoliakov, Alexander; Jotkowitz, Alan; Barski, Leonid

    2015-10-01

    The 2009 pandemic influenza A/H1N1 developed as a novel swine influenza which caused more diseases among younger age groups than in the elderly. Severe hypoxemic respiratory failure from A/H1N1 pneumonia resulted in an increased need for ICU beds. Several risk groups were identified that were at a higher risk for adverse outcomes. Pregnant women were a particularly vulnerable group of patients The CDC reported on the first ten patients with severe illness and acute hypoxemic respiratory failure associated with A/H1N1 infection, none of whom were pregnant, but they noticed that half of the patients had a pulmonary embolism. During a four-month period from September to December 2009, 252 patients were admitted to our hospital with confirmed pandemic influenza H1N1 by real-time reverse transcriptase-polymerase chain reaction test (rRT-PCR). We cared for twenty patients (7.9%) admitted to MICU with severe A/H1N1. Results on Thrombotic events were identified in five (25%) of our critically ill patients. We recommend that patients with severe influenza A/H1N1 pneumonitis and respiratory failure be administered DVT prophylaxis in particular if there are additional risk factors for TVE. Further prospective studies on the relationship of influenza A/H1N1 and VTE are needed. Copyright © 2015 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  20. A Phylogeny-Based Global Nomenclature System and Automated Annotation Tool for H1 Hemagglutinin Genes from Swine Influenza A Viruses

    PubMed Central

    Macken, Catherine A.; Lewis, Nicola S.; Van Reeth, Kristien; Brown, Ian H.; Swenson, Sabrina L.; Simon, Gaëlle; Saito, Takehiko; Berhane, Yohannes; Ciacci-Zanella, Janice; Pereda, Ariel; Davis, C. Todd; Donis, Ruben O.; Webby, Richard J.

    2016-01-01

    ABSTRACT The H1 subtype of influenza A viruses (IAVs) has been circulating in swine since the 1918 human influenza pandemic. Over time, and aided by further introductions from nonswine hosts, swine H1 viruses have diversified into three genetic lineages. Due to limited global data, these H1 lineages were named based on colloquial context, leading to a proliferation of inconsistent regional naming conventions. In this study, we propose rigorous phylogenetic criteria to establish a globally consistent nomenclature of swine H1 virus hemagglutinin (HA) evolution. These criteria applied to a data set of 7,070 H1 HA sequences led to 28 distinct clades as the basis for the nomenclature. We developed and implemented a web-accessible annotation tool that can assign these biologically informative categories to new sequence data. The annotation tool assigned the combined data set of 7,070 H1 sequences to the correct clade more than 99% of the time. Our analyses indicated that 87% of the swine H1 viruses from 2010 to the present had HAs that belonged to 7 contemporary cocirculating clades. Our nomenclature and web-accessible classification tool provide an accurate method for researchers, diagnosticians, and health officials to assign clade designations to HA sequences. The tool can be updated readily to track evolving nomenclature as new clades emerge, ensuring continued relevance. A common global nomenclature facilitates comparisons of IAVs infecting humans and pigs, within and between regions, and can provide insight into the diversity of swine H1 influenza virus and its impact on vaccine strain selection, diagnostic reagents, and test performance, thereby simplifying communication of such data. IMPORTANCE A fundamental goal in the biological sciences is the definition of groups of organisms based on evolutionary history and the naming of those groups. For influenza A viruses (IAVs) in swine, understanding the hemagglutinin (HA) genetic lineage of a circulating strain aids

  1. Rapid death of duck cells infected with influenza: a potential mechanism for host resistance to H5N1.

    PubMed

    Kuchipudi, Suresh V; Dunham, Stephen P; Nelli, Rahul; White, Gavin A; Coward, Vivien J; Slomka, Marek J; Brown, Ian H; Chang, Kin Chow

    2012-01-01

    Aquatic birds are the natural reservoir for most subtypes of influenza A, and a source of novel viruses with the potential to cause human pandemics, fatal zoonotic disease or devastating epizootics in poultry. It is well recognised that waterfowl typically show few clinical signs following influenza A infection, in contrast, terrestrial poultry such as chickens may develop severe disease with rapid death following infection with highly pathogenic avian influenza. This study examined the cellular response to influenza infection in primary cells derived from resistant (duck) and susceptible (chicken) avian hosts. Paradoxically, we observed that duck cells underwent rapid cell death following infection with low pathogenic avian H2N3, classical swine H1N1 and 'classical' highly pathogenic H5N1 viruses. Dying cells showed morphological features of apoptosis, increased DNA fragmentation and activation of caspase 3/7. Following infection of chicken cells, cell death occurred less rapidly, accompanied by reduced DNA fragmentation and caspase activation. Duck cells produced similar levels of viral RNA but less infectious virus, in comparison with chicken cells. Such rapid cell death was not observed in duck cells infected with a contemporary Eurasian lineage H5N1 fatal to ducks. The induction of rapid death in duck cells may be part of a mechanism of host resistance to influenza A, with the loss of this response leading to increased susceptibility to emergent strains of H5N1. These studies provide novel insights that should help resolve the long-standing enigma of host-pathogen relationships for highly pathogenic and zoonotic avian influenza.

  2. An outbreak of influenza A/H3N2 in a Zambian school dormitory.

    PubMed

    Mizuta, K; Oshitani, H; Mpabalwani, E M; Kasolo, F C; Luo, N P; Suzuki, H; Numazaki, Y

    1995-03-01

    There was an outbreak of "a mysterious disease" at a Zambian school dormitory in September, 1993. Investigation with questionnaire and collection of throat swab specimens for virus isolation were carried out on 46 patients to identify the causative agent. In this outbreak, most of the patients showed similar symptoms such as fever, headache, sore throat, cough, etc. The disease had spread to all dormitories within a couple of days after the onset of the first cases. From these patients, 13 influenza viruses A/H3N2 were isolated on MDCK cell line. This was a first ever confirmed outbreak of influenza virus infection in Zambia.

  3. Reintroduction of highly pathogenic avian influenza A/H5N8 virus of clade 2.3.4.4. in Russia.

    PubMed

    Marchenko, Vasiliy Y; Susloparov, Ivan M; Komissarov, Andrey B; Fadeev, Artem; Goncharova, Nataliya I; Shipovalov, Andrey V; Svyatchenko, Svetlana V; Durymanov, Alexander G; Ilyicheva, Tatyana N; Salchak, Lyudmila K; Svintitskaya, Elena P; Mikheev, Valeriy N; Ryzhikov, Alexander B

    2017-05-01

    In the spring of 2016, a loss of wild birds was observed during the monitoring of avian influenza virus activity in the Republic of Tyva. That outbreak was caused by influenza H5N8 virus of clade 2.3.4.4. In the fall, viruses of H5N8 clade 2.3.4.4 were propagated in European countries. This paper presents some results of analysis of the virus strains isolated during the spring and fall seasons in 2016 in the Russian Federation. The investigated strains were highly pathogenic for mice, and some of their antigenic and genetic features differed from those of an H5N8 strain that circulated in 2014 in Russia.

  4. Antigenic and Molecular Characterization of Avian Influenza A(H9N2) Viruses, Bangladesh

    PubMed Central

    Shanmuganatham, Karthik; Feeroz, Mohammed M.; Jones-Engel, Lisa; Smith, Gavin J.D.; Fourment, Mathieu; Walker, David; McClenaghan, Laura; Alam, S.M. Rabiul; Hasan, M. Kamrul; Seiler, Patrick; Franks, John; Danner, Angie; Barman, Subrata; McKenzie, Pamela; Krauss, Scott; Webby, Richard J.

    2013-01-01

    Human infection with avian influenza A(H9N2) virus was identified in Bangladesh in 2011. Surveillance for influenza viruses in apparently healthy poultry in live-bird markets in Bangladesh during 2008–2011 showed that subtype H9N2 viruses are isolated year-round, whereas highly pathogenic subtype H5N1 viruses are co-isolated with subtype H9N2 primarily during the winter months. Phylogenetic analysis of the subtype H9N2 viruses showed that they are reassortants possessing 3 gene segments related to subtype H7N3; the remaining gene segments were from the subtype H9N2 G1 clade. We detected no reassortment with subtype H5N1 viruses. Serologic analyses of subtype H9N2 viruses from chickens revealed antigenic conservation, whereas analyses of viruses from quail showed antigenic drift. Molecular analysis showed that multiple mammalian-specific mutations have become fixed in the subtype H9N2 viruses, including changes in the hemagglutinin, matrix, and polymerase proteins. Our results indicate that these viruses could mutate to be transmissible from birds to mammals, including humans. PMID:23968540

  5. The genomic evolution of H1 influenza A viruses from swine detected in the United States between 2009 and 2016

    PubMed Central

    Gao, Shibo; Anderson, Tavis K.; Walia, Rasna R.; Dorman, Karin S.; Janas-Martindale, Alicia

    2017-01-01

    Transmission of influenza A virus (IAV) from humans to swine occurs with relative frequency and is a critical contributor to swine IAV diversity. Subsequent to the introduction of these human seasonal lineages, there is often reassortment with endemic viruses and antigenic drift. To address whether particular genome constellations contributed to viral persistence following the introduction of the 2009 H1N1 human pandemic virus to swine in the USA, we collated and analysed 616 whole genomes of swine H1 isolates. For each gene, sequences were aligned, the best-known maximum likelihood phylogeny was inferred, and each virus was assigned a clade based upon its evolutionary history. A time-scaled Bayesian approach was implemented for the haemagglutinin (HA) gene to determine the patterns of genetic diversity over time. From these analyses, we observed an increase in genome diversity across all H1 lineages and clades, with the H1-γ and H1-δ1 genetic clades containing the greatest number of unique genome patterns. We documented 74 genome patterns from 2009 to 2016, of which 3 genome patterns were consistently detected at a significantly higher level than others across the entire time period. Eight genome patterns increased significantly, while five genome patterns were shown to decline in detection over time. Viruses with genome patterns identified as persisting in the US swine population may possess a greater capacity to infect and transmit in swine. This study highlights the emerging genetic diversity of US swine IAV from 2009 to 2016, with implications for swine and public health and vaccine control efforts. PMID:28758634

  6. Determination of antigenicity-altering patches on the major surface protein of human influenza A/H3N2 viruses

    PubMed Central

    Kratsch, Christina; Klingen, Thorsten R.; Mümken, Linda; Steinbrück, Lars; McHardy, Alice C.

    2016-01-01

    Human influenza viruses are rapidly evolving RNA viruses that cause short-term respiratory infections with substantial morbidity and mortality in annual epidemics. Uncovering the general principles of viral coevolution with human hosts is important for pathogen surveillance and vaccine design. Protein regions are an appropriate model for the interactions between two macromolecules, but the currently used epitope definition for the major antigen of influenza viruses, namely hemagglutinin, is very broad. Here, we combined genetic, evolutionary, antigenic, and structural information to determine the most relevant regions of the hemagglutinin of human influenza A/H3N2 viruses for interaction with human immunoglobulins. We estimated the antigenic weights of amino acid changes at individual sites from hemagglutination inhibition data using antigenic tree inference followed by spatial clustering of antigenicity-altering protein sites on the protein structure. This approach determined six relevant areas (patches) for antigenic variation that had a key role in the past antigenic evolution of the viruses. Previous transitions between successive predominating antigenic types of H3N2 viruses always included amino acid changes in either the first or second antigenic patch. Interestingly, there was only partial overlap between the antigenic patches and the patches under strong positive selection. Therefore, besides alterations of antigenicity, other interactions with the host may shape the evolution of human influenza A/H3N2 viruses. PMID:27774294

  7. Antigenic Maps of Influenza A(H3N2) Produced With Human Antisera Obtained After Primary Infection.

    PubMed

    Fonville, Judith M; Fraaij, Pieter L A; de Mutsert, Gerrie; Wilks, Samuel H; van Beek, Ruud; Fouchier, Ron A M; Rimmelzwaan, Guus F

    2016-01-01

    Antigenic characterization of influenza viruses is typically based on hemagglutination inhibition (HI) assay data for viral isolates tested against strain-specific postinfection ferret antisera. Here, similar virus characterizations were performed using serological data from humans with primary influenza A(H3N2) infection. We screened sera collected between 1995 and 2011 from children between 9 and 24 months of age for influenza virus antibodies, performed HI tests for the positive sera against 23 influenza viruses isolated between 1989 and 2011, and measured HI titers of antisera against influenza A(H3N2) from 24 ferrets against the same panel of viruses. Of the 17 positive human sera, 6 had a high response, showing HI patterns that would be expected from primary infection antisera, while 11 sera had lower, more dispersed patterns of reactivity that are not easily explained. The antigenic map based on the high-response human HI data was similar to the map created using ferret data. Although the overall structure of the ferret and human antigenic maps is similar, local differences in virus positions indicate that the human and ferret immune system might see antigenic properties of viruses differently. Further studies are needed to establish the degree of similarity between serological patterns in ferret and human data. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America.

  8. Novel H5N8 clade 2.3.4.4 highly pathogenic avian influenza virus in wild awuatic birds, Russia, 2016

    USDA-ARS?s Scientific Manuscript database

    H5N1 high pathogenicity avian influenza virus (HPAIV) emerged in 1996 in Guangdong China (Gs/GD) and has evolved into multiple genetic clades. Since 2008, HPAIV H5 clade 2.3.4 with N2, N5 and N8 neuraminidase subtypes have been identified in mainland China and outbreak of HPAIV H5N8 clade 2.3.4.4 ou...

  9. Isolation and characterization of an H9N2 influenza virus isolated in Argentina

    PubMed Central

    Xu, Kemin; Ferreri, Lucas; Rimondi, Agustina; Olivera, Valeria; Romano, Marcelo; Ferreyra, Hebe; Rago, Virgina; Uhart, Marcela; Chen, Hongjun; Sutton, Troy; Pereda, Ariel; Perez, Daniel R.

    2016-01-01

    As part of our ongoing efforts on animal influenza surveillance in Argentina, an H9N2 virus was isolated from a wild aquatic bird (Netta peposaca), A/rosy-billed pochard/Argentina/CIP051-559/2007 (H9N2) – herein referred to as 559/H9N2. Due to the important role that H9N2 viruses play in the ecology of influenza in nature, the 559/H9N2 isolate was characterized molecularly and biologically. Phylogenetic analysis of the HA gene revealed that the 559/H9N2 virus maintained an independent evolutionary pathway and shared a sister-group relationship with North American viruses, suggesting a common ancestor. The rest of the genome segments clustered with viruses from South America. Experimental inoculation of the 559/H9N2 in chickens and quail revealed efficient replication and transmission only in quail. Our results add to the notion of the unique evolutionary trend of avian influenza viruses in South America. Our study increases our understanding of H9N2 viruses in nature and emphasizes the importance of expanding animal influenza surveillance efforts to better define the ecology of influenza viruses at a global scale. PMID:22709552

  10. Reassortant clade 2.3.4.4 of highly pathogenic avian influenza A (H5N6) virus, Taiwan, 2017

    USDA-ARS?s Scientific Manuscript database

    A highly pathogenic avian influenza A(H5N6) virus of clade 2.3.4.4 was detected in a domestic duck found dead in Taiwan during February 2017. The endemic situation and continued evolution of various reassortant highly pathogenic avian influenza viruses in Taiwan warrant concern about further reassor...

  11. Routes of transmission during a nosocomial influenza A(H3N2) outbreak among geriatric patients and healthcare workers.

    PubMed

    Eibach, D; Casalegno, J-S; Bouscambert, M; Bénet, T; Regis, C; Comte, B; Kim, B-A; Vanhems, P; Lina, B

    2014-03-01

    Influenza presents a life-threatening infection for hospitalized geriatric patients, who might be nosocomially infected via healthcare workers (HCWs), other patients or visitors. In the 2011/2012 influenza season an influenza A(H3N2) outbreak occurred in the geriatric department at the Hôpital Edouard Herriot, Lyon. To clarify the transmission chain for this influenza A(H3N2) outbreak by sequence analysis and to identify preventive measures. Laboratory testing of patients with influenza-like illness in the acute care geriatric department revealed 22 cases of influenza between 19th February and 15th March 2012. Incidences for patients and HCWs were calculated and possible epidemiological links were analysed using a questionnaire. Neuraminidase and haemagglutinin genes of culture-positive samples and community influenza samples were sequenced and clustered to detect patients with identical viral strains. Sixteen patients and six HCWs were affected, resulting in an attack rate of 24% and 11% respectively. Six nosocomial infections were recorded. The sequence analysis confirmed three independent influenza clusters on three different sections of the geriatric ward. For at least two clusters, an HCW source was determined. Epidemiological and microbiological results confirm influenza transmission from HCWs to patients. A higher vaccination rate, isolation measures and better hand hygiene are recommended in order to prevent outbreaks in future influenza seasons. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  12. Clinical and epidemiologic characteristics of an outbreak of novel H1N1 (swine origin) influenza A virus among United States military beneficiaries.

    PubMed

    Crum-Cianflone, Nancy F; Blair, Patrick J; Faix, Dennis; Arnold, John; Echols, Sara; Sherman, Sterling S; Tueller, John E; Warkentien, Tyler; Sanguineti, Gabriela; Bavaro, Mary; Hale, Braden R

    2009-12-15

    A novel swine-origin influenza A (H1N1) virus was identified in March 2009 and subsequently caused worldwide outbreaks. The San Diego region was an early focal point of the emerging pandemic. We describe the clinical and epidemiologic characteristics of this novel strain in a military population to assist in future outbreak prevention and control efforts. We performed an epidemiologic evaluation of novel H1N1 virus infections diagnosed in San Diego County among 96,258 local US military beneficiaries. The structured military medical system afforded the ability to obtain precise epidemiologic information on the impact on H1N1 virus infection in a population. The novel H1N1 virus was confirmed using real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 21 April through 8 May 2009, 761 patients presented with influenza-like illness and underwent rRT-PCR testing. Of these patients, 97 had confirmed novel H1N1 virus infection, with an incidence rate of 101 cases per 100,000 persons. The median age of H1N1 patients with H1N1 virus infection was 21 years (interquartile range, 15-25 years). Fever was a universal symptom in patients with H1N1 virus infection; other symptoms included cough (present in 96% of patients), myalgia or arthralgia (57%), and sore throat (51%). Sixty-eight (70%) of our patients had an identifiable epidemiologic link to another confirmed patient. The largest cluster of cases of H1N1 virus infection occurred on a Navy ship and involved 32 (8%) of 402 crew members; the secondary attack rate was 6%-14%. The rapid influenza testing that was used during this outbreak had a sensitivity of 51% and specificity of 98%, compared with rRT-PCR. Only 1 patient was hospitalized, and there were no deaths. A novel H1N1 influenza A virus caused a significant outbreak among military beneficiaries in San Diego County, including a significant cluster of cases onboard a Navy ship. The outbreak described here primarily affected adolescents and young

  13. Distribution of sialic acid receptors and influenza A virus of avian and swine origin in experimentally infected pigs.

    PubMed

    Trebbien, Ramona; Larsen, Lars E; Viuff, Birgitte M

    2011-09-08

    Pigs are considered susceptible to influenza A virus infections from different host origins because earlier studies have shown that they have receptors for both avian (sialic acid-alpha-2,3-terminal saccharides (SA-alpha-2,3)) and swine/human (SA-alpha-2,6) influenza viruses in the upper respiratory tract. Furthermore, experimental and natural infections in pigs have been reported with influenza A virus from avian and human sources. This study investigated the receptor distribution in the entire respiratory tract of pigs using specific lectins Maackia Amurensis (MAA) I, and II, and Sambucus Nigra (SNA). Furthermore, the predilection sites of swine influenza virus (SIV) subtypes H1N1 and H1N2 as well as avian influenza virus (AIV) subtype H4N6 were investigated in the respiratory tract of experimentally infected pigs using immunohistochemical methods. SIV antigen was widely distributed in bronchi, but was also present in epithelial cells of the nose, trachea, bronchioles, and alveolar type I and II epithelial cells in severely affected animals. AIV was found in the lower respiratory tract, especially in alveolar type II epithelial cells and occasionally in bronchiolar epithelial cells. SA-alpha-2,6 was the predominant receptor in all areas of the respiratory tract with an average of 80-100% lining at the epithelial cells. On the contrary, the SA-alpha-2,3 was not present (0%) at epithelial cells of nose, trachea, and most bronchi, but was found in small amounts in bronchioles, and in alveoli reaching an average of 20-40% at the epithelial cells. Interestingly, the receptor expression of both SA-alpha-2,3 and 2,6 was markedly diminished in influenza infected areas compared to non-infected areas. A difference in predilection sites between SIV and AIV virus was found, and this difference was in accordance with the distribution of the SA-alpha-2,6 and SA-alpha-2,3 receptor, respectively. The results indicated that the distribution of influenza A virus receptors in pigs

  14. The emergence and evolution of influenza A (H1α) viruses in swine in Canada and the United States.

    PubMed

    Nelson, Martha I; Culhane, Marie R; Trovão, Nídia S; Patnayak, Devi P; Halpin, Rebecca A; Lin, Xudong; Shilts, Meghan H; Das, Suman R; Detmer, Susan E

    2017-11-01

    Swine are a key reservoir host for influenza A viruses (IAVs), with the potential to cause global pandemics in humans. Gaps in surveillance in many of the world's largest swine populations impede our understanding of how novel viruses emerge and expand their spatial range in pigs. Although US swine are intensively sampled, little is known about IAV diversity in Canada's population of ~12 million pigs. By sequencing 168 viruses from multiple regions of Canada, our study reveals that IAV diversity has been underestimated in Canadian pigs for many years. Critically, a new H1 clade has emerged in Canada (H1α-3), with a two-amino acid deletion at H1 positions 146-147, that experienced rapid growth in Manitoba's swine herds during 2014-2015. H1α-3 viruses also exhibit a higher capacity to invade US swine herds, resulting in multiple recent introductions of the virus into the US Heartland following large-scale movements of pigs in this direction. From the Heartland, H1α-3 viruses have disseminated onward to both the east and west coasts of the United States, and may become established in Appalachia. These findings demonstrate how long-distance trading of live pigs facilitates the spread of IAVs, increasing viral genetic diversity and complicating pathogen control. The proliferation of novel H1α-3 viruses also highlights the need for expanded surveillance in a Canadian swine population that has long been overlooked, and may have implications for vaccine design.

  15. Effects of egg-adaptation on receptor-binding and antigenic properties of recent influenza A (H3N2) vaccine viruses.

    PubMed

    Parker, Lauren; Wharton, Stephen A; Martin, Stephen R; Cross, Karen; Lin, Yipu; Liu, Yan; Feizi, Ten; Daniels, Rodney S; McCauley, John W

    2016-06-01

    Influenza A virus (subtype H3N2) causes seasonal human influenza and is included as a component of influenza vaccines. The majority of vaccine viruses are isolated and propagated in eggs, which commonly results in amino acid substitutions in the haemagglutinin (HA) glycoprotein. These substitutions can affect virus receptor-binding and alter virus antigenicity, thereby, obfuscating the choice of egg-propagated viruses for development into candidate vaccine viruses. To evaluate the effects of egg-adaptive substitutions seen in H3N2 vaccine viruses on sialic acid receptor-binding, we carried out quantitative measurement of virus receptor-binding using surface biolayer interferometry with haemagglutination inhibition (HI) assays to correlate changes in receptor avidity with antigenic properties. Included in these studies was a panel of H3N2 viruses generated by reverse genetics containing substitutions seen in recent egg-propagated vaccine viruses and corresponding cell culture-propagated wild-type viruses. These assays provide a quantitative approach to investigating the importance of individual amino acid substitutions in influenza receptor-binding. Results show that viruses with egg-adaptive HA substitutions R156Q, S219Y, and I226N, have increased binding avidity to α2,3-linked receptor-analogues and decreased binding avidity to α2,6-linked receptor-analogues. No measurable binding was detected for the viruses with amino acid substitution combination 156Q+219Y and receptor-binding increased in viruses where egg-adaptation mutations were introduced into cell culture-propagated virus. Substitutions at positions 156 and 190 appeared to be primarily responsible for low reactivity in HI assays with post-infection ferret antisera raised against 2012-2013 season H3N2 viruses. Egg-adaptive substitutions at position 186 caused substantial differences in binding avidity with an insignificant effect on antigenicity.

  16. A Candidate H1N1 Pandemic Influenza Vaccine Elicits Protective Immunity in Mice

    PubMed Central

    Steitz, Julia; Barlow, Peter G.; Hossain, Jaber; Kim, Eun; Okada, Kaori; Kenniston, Tom; Rea, Sheri; Donis, Ruben O.; Gambotto, Andrea

    2010-01-01

    Background In 2009 a new pandemic disease appeared and spread globally. The recent emergence of the pandemic influenza virus H1N1 first isolated in Mexico and USA raised concerns about vaccine availability. We here report our development of an adenovirus-based influenza H1N1 vaccine tested for immunogenicity and efficacy to confer protection in animal model. Methods We generated two adenovirus(Ad5)-based influenza vaccine candidates encoding the wildtype or a codon-optimized hemagglutinin antigen (HA) from the recently emerged swine influenza isolate A/California/04/2009 (H1N1)pdm. After verification of antigen expression, immunogenicity of the vaccine candidates were tested in a mouse model using dose escalations for subcutaneous immunization. Sera of immunized animals were tested in microneutalization and hemagglutination inhibition assays for the presence of HA-specific antibodies. HA-specific T-cells were measured in IFNγ Elispot assays. The efficiency of the influenza vaccine candidates were evaluated in a challenge model by measuring viral titer in lung and nasal turbinate 3 days after inoculation of a homologous H1N1 virus. Conclusions/Significance A single immunization resulted in robust cellular and humoral immune response. Remarkably, the intensity of the immune response was substantially enhanced with codon-optimized antigen, indicating the benefit of manipulating the genetic code of HA antigens in the context of recombinant influenza vaccine design. These results highlight the value of advanced technologies in vaccine development and deployment in response to infections with pandemic potential. Our study emphasizes the potential of an adenoviral-based influenza vaccine platform with the benefits of speed of manufacture and efficacy of a single dose immunization. PMID:20463955

  17. Influenza H7N9 and H9N2 Viruses: Coexistence in Poultry Linked to Human H7N9 Infection and Genome Characteristics

    PubMed Central

    Yu, Xinfen; Jin, Tao; Cui, Yujun; Pu, Xiaoying; Li, Jun; Xu, Jin; Liu, Guang; Jia, Huijue; Liu, Dan; Song, Shili; Yu, Yang; Xie, Li; Huang, Renjie; Ding, Hua; Kou, Yu; Zhou, Yinyan; Wang, Yayu; Xu, Xun; Yin, Ye; Wang, Jian; Guo, Chenyi; Yang, Xianwei; Hu, Liangping; Wu, Xiaopeng; Wang, Hailong; Liu, Jun; Zhao, Guoqiu; Zhou, Jiyong; Gao, George F.; Yang, Ruifu; Wang, Jun

    2014-01-01

    ABSTRACT Avian influenza virus A of the novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China. Live poultry markets were suspected locations of the human H7N9 infection sources, based on the cases' exposure histories and sequence similarities between viral isolates. To explore the role of live poultry markets in the origin of the novel H7N9 virus, we systematically examined poultry and environmental specimens from local markets and farms in Hangzhou, using real-time reverse transcription-PCR (RT-PCR) as well as high-throughput next-generation sequencing (NGS). RT-PCR identified specimens positive for the H7 and N9 genomic segments in all of the 12 poultry markets epidemiologically linked to 10 human H7N9 cases. Chickens, ducks, and environmental specimens from the markets contained heavily mixed subtypes, including H7, N9, H9, and N2 and sometimes H5 and N1. The idea of the coexistence of H7N9 and H9N2 subtypes in chickens was further supported by metagenomic sequencing. In contrast, human H7N9 infection cases (n = 31) were all negative for H9N2 virus according to real-time RT-PCR. The six internal segments were indistinguishable for the H7N9 and H9N2 viruses. The H9, N2, and internal-segment sequences were very close to the sequence of the H9N2 virus circulating in chickens in China recently. Our results provide direct evidence that H9N2 strains coexisted with the novel human-pathogenic H7N9 influenza virus in epidemiologically linked live poultry markets. Avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus and continues to do so. IMPORTANCE Our results suggest that avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus, a novel reassortant avian influenza virus A subtype, and continues to do so. The finding helps shed light on how the H7N9 virus emerged, spread, and transmitted to humans. It is of

  18. Influenza H7N9 and H9N2 viruses: coexistence in poultry linked to human H7N9 infection and genome characteristics.

    PubMed

    Yu, Xinfen; Jin, Tao; Cui, Yujun; Pu, Xiaoying; Li, Jun; Xu, Jin; Liu, Guang; Jia, Huijue; Liu, Dan; Song, Shili; Yu, Yang; Xie, Li; Huang, Renjie; Ding, Hua; Kou, Yu; Zhou, Yinyan; Wang, Yayu; Xu, Xun; Yin, Ye; Wang, Jian; Guo, Chenyi; Yang, Xianwei; Hu, Liangping; Wu, Xiaopeng; Wang, Hailong; Liu, Jun; Zhao, Guoqiu; Zhou, Jiyong; Pan, Jingcao; Gao, George F; Yang, Ruifu; Wang, Jun

    2014-03-01

    Avian influenza virus A of the novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China. Live poultry markets were suspected locations of the human H7N9 infection sources, based on the cases' exposure histories and sequence similarities between viral isolates. To explore the role of live poultry markets in the origin of the novel H7N9 virus, we systematically examined poultry and environmental specimens from local markets and farms in Hangzhou, using real-time reverse transcription-PCR (RT-PCR) as well as high-throughput next-generation sequencing (NGS). RT-PCR identified specimens positive for the H7 and N9 genomic segments in all of the 12 poultry markets epidemiologically linked to 10 human H7N9 cases. Chickens, ducks, and environmental specimens from the markets contained heavily mixed subtypes, including H7, N9, H9, and N2 and sometimes H5 and N1. The idea of the coexistence of H7N9 and H9N2 subtypes in chickens was further supported by metagenomic sequencing. In contrast, human H7N9 infection cases (n = 31) were all negative for H9N2 virus according to real-time RT-PCR. The six internal segments were indistinguishable for the H7N9 and H9N2 viruses. The H9, N2, and internal-segment sequences were very close to the sequence of the H9N2 virus circulating in chickens in China recently. Our results provide direct evidence that H9N2 strains coexisted with the novel human-pathogenic H7N9 influenza virus in epidemiologically linked live poultry markets. Avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus and continues to do so. Our results suggest that avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus, a novel reassortant avian influenza virus A subtype, and continues to do so. The finding helps shed light on how the H7N9 virus emerged, spread, and transmitted to humans. It is of considerable

  19. H7N9 Influenza Virus Is More Virulent in Ferrets than 2009 Pandemic H1N1 Influenza Virus.

    PubMed

    Yum, Jung; Ku, Keun Bon; Kim, Hyun Soo; Seo, Sang Heui

    2015-12-01

    The novel H7N9 influenza virus has been infecting humans in China since February 2013 and with a mortality rate of about 40%. This study compared the pathogenicity of the H7N9 and 2009 pandemic H1N1 influenza viruses in a ferret model, which shows similar symptoms to those of humans infected with influenza viruses. The H7N9 influenza virus caused a more severe disease than did the 2009 pandemic H1N1 influenza virus. All of the ferrets infected with the H7N9 influenza virus had died by 6 days after infection, while none of those infected with the 2009 pandemic H1N1 influenza virus died. Ferrets infected with the H7N9 influenza virus had higher viral titers in their lungs than did those infected with the 2009 pandemic H1N1 influenza virus. Histological findings indicated that hemorrhagic pneumonia was caused by infection with the H7N9 influenza virus, but not with the 2009 pandemic H1N1 influenza virus. In addition, the lung tissues of ferrets infected with the H7N9 influenza virus contained higher levels of chemokines than did those of ferrets infected with the 2009 pandemic H1N1 influenza virus. This study suggests that close monitoring is needed to prevent human infection by the lethal H7N9 influenza virus.

  20. Using routine surveillance data to estimate the epidemic potential of emerging zoonoses: application to the emergence of US swine origin influenza A H3N2v virus.

    PubMed

    Cauchemez, Simon; Epperson, Scott; Biggerstaff, Matthew; Swerdlow, David; Finelli, Lyn; Ferguson, Neil M

    2013-01-01

    Prior to emergence in human populations, zoonoses such as SARS cause occasional infections in human populations exposed to reservoir species. The risk of widespread epidemics in humans can be assessed by monitoring the reproduction number R (average number of persons infected by a human case). However, until now, estimating R required detailed outbreak investigations of human clusters, for which resources and expertise are not always available. Additionally, existing methods do not correct for important selection and under-ascertainment biases. Here, we present simple estimation methods that overcome many of these limitations. Our approach is based on a parsimonious mathematical model of disease transmission and only requires data collected through routine surveillance and standard case investigations. We apply it to assess the transmissibility of swine-origin influenza A H3N2v-M virus in the US, Nipah virus in Malaysia and Bangladesh, and also present a non-zoonotic example (cholera in the Dominican Republic). Estimation is based on two simple summary statistics, the proportion infected by the natural reservoir among detected cases (G) and among the subset of the first detected cases in each cluster (F). If detection of a case does not affect detection of other cases from the same cluster, we find that R can be estimated by 1-G; otherwise R can be estimated by 1-F when the case detection rate is low. In more general cases, bounds on R can still be derived. We have developed a simple approach with limited data requirements that enables robust assessment of the risks posed by emerging zoonoses. We illustrate this by deriving transmissibility estimates for the H3N2v-M virus, an important step in evaluating the possible pandemic threat posed by this virus. Please see later in the article for the Editors' Summary.

  1. Molecular subtyping of European swine influenza viruses and scaling to high-throughput analysis.

    PubMed

    Bonin, Emilie; Quéguiner, Stéphane; Woudstra, Cédric; Gorin, Stéphane; Barbier, Nicolas; Harder, Timm C; Fach, Patrick; Hervé, Séverine; Simon, Gaëlle

    2018-01-10

    Swine influenza is a respiratory infection of pigs that may have a significant economic impact in affected herds and pose a threat to the human population since swine influenza A viruses (swIAVs) are zoonotic pathogens. Due to the increasing genetic diversity of swIAVs and because novel reassortants or variants may become enzootic or have zoonotic implications, surveillance is strongly encouraged. Therefore, diagnostic tests and advanced technologies able to identify the circulating strains rapidly are critically important. Several reverse transcription real-time PCR assays (RT-qPCRs) were developed to subtype European swIAVs in clinical samples previously identified as containing IAV genome. The RT-qPCRs aimed to discriminate HA genes of four H1 genetic lineages (H1 av , H1 hu , H1 huΔ146-147 , H1pdm) and one H3 lineage, and NA genes of two N1 lineages (N1, N1pdm) and one N2 lineage. After individual validation, each RT-qPCR was adapted to high-throughput analyses in parallel to the amplification of the IAV M gene (target for IAV detection) and the β-actin gene (as an internal control), in order to test the ten target genes simultaneously on a large number of clinical samples, using low volumes of reagents and RNA extracts. The RT-qPCRs dedicated to IAV molecular subtyping enabled the identification of swIAVs from the four viral subtypes that are known to be enzootic in European pigs, i.e. H1 av N1, H1 hu N2, H3N2 and H1N1pdm. They also made it possible to discriminate a new antigenic variant (H1 hu N2 Δ146-147 ) among H1 hu N2 viruses, as well as reassortant viruses, such as H1 hu N1 or H1 av N2 for example, and virus mixtures. These PCR techniques exhibited a gain in sensitivity as compared to end-point RT-PCRs, enabling the characterization of biological samples with low genetic loads, with considerable time saving. Adaptation to high-throughput analyses appeared effective, both in terms of specificity and sensitivity. This new development opens novel

  2. Restored PB1-F2 in the 2009 Pandemic H1N1 Influenza Virus Has Minimal Effects in Swine

    PubMed Central

    Pena, Lindomar; Loving, Crystal L.; Henningson, Jamie N.; Lager, Kelly M.; Lorusso, Alessio

    2012-01-01

    PB1-F2 is an 87- to 90-amino-acid-long protein expressed by certain influenza A viruses. Previous studies have shown that PB1-F2 contributes to virulence in the mouse model; however, its role in natural hosts—pigs, humans, or birds—remains largely unknown. Outbreaks of domestic pigs infected with the 2009 pandemic H1N1 influenza virus (pH1N1) have been detected worldwide. Unlike previous pandemic strains, pH1N1 viruses do not encode a functional PB1-F2 due to the presence of three stop codons resulting in premature truncation after codon 11. However, pH1N1s have the potential to acquire the full-length form of PB1-F2 through mutation or reassortment. In this study, we assessed whether restoring the full-length PB1-F2 open reading frame (ORF) in the pH1N1 background would have an effect on virus replication and virulence in pigs. Restoring the PB1-F2 ORF resulted in upregulation of viral polymerase activity at early time points in vitro and enhanced virus yields in porcine respiratory explants and in the lungs of infected pigs. There was an increase in the severity of pneumonia in pigs infected with isogenic virus expressing PB1-F2 compared to the wild-type (WT) pH1N1. The extent of microscopic pneumonia correlated with increased pulmonary levels of alpha interferon and interleukin-1β in pigs infected with pH1N1 encoding a functional PB1-F2 but only early in the infection. Together, our results indicate that PB1-F2 in the context of pH1N1 moderately modulates viral replication, lung histopathology, and local cytokine response in pigs. PMID:22379102

  3. Educating youth swine exhibitors on influenza A virus transmission at agricultural fairs.

    PubMed

    Nolting, J M; Midla, J; Whittington, M S; Scheer, S D; Bowman, A S

    2018-02-01

    Influenza A virus (IAV) is a major zoonotic pathogen that threatens global public health. Novel strains of influenza A viruses pose a significant risk to public health due to their pandemic potential, and transmission of influenza A viruses from animals to humans is an important mechanism in the generation and introduction of IAVs that threaten human health. The purpose of this descriptive correlational study was to develop real-life training scenarios to better inform swine exhibitors of the risks they may encounter when influenza A viruses are present in swine. Educational activities were implemented in five Ohio counties where exhibition swine had historically been shedding influenza A viruses during the county fair. A total of 146 youth swine exhibitors participated in the educational programme, and an increase in the knowledge base of these youth was documented. It is expected that educating youth exhibitors about exposure to influenza A virus infections in the swine they are exhibiting will result in altered behaviours and animal husbandry practices that will improve both human and animal health. © 2017 Blackwell Verlag GmbH.

  4. A Simple Restriction Fragment Length Polymorphism-Based Strategy That Can Distinguish the Internal Genes of Human H1N1, H3N2, and H5N1 Influenza A Viruses

    PubMed Central

    Cooper, Lynn A.; Subbarao, Kanta

    2000-01-01

    A simple molecular technique for rapid genotyping was developed to monitor the internal gene composition of currently circulating influenza A viruses. Sequence information from recent H1N1, H3N2, and H5N1 human virus isolates was used to identify conserved regions within each internal gene, and gene-specific PCR primers capable of amplifying all three virus subtypes were designed. Subtyping was based on subtype-specific restriction fragment length polymorphism (RFLP) patterns within the amplified regions. The strategy was tested in a blinded fashion using 10 control viruses of each subtype (total, 30) and was found to be very effective. Once standardized, the genotyping method was used to identify the origin of the internal genes of 51 influenza A viruses isolated from humans in Hong Kong during and immediately following the 1997–1998 H5N1 outbreak. No avian-human or H1-H3 reassortants were detected. Less than 2% (6 of 486) of the RFLP analyses were inconclusive; all were due to point mutations within a restriction site. The technique was also used to characterize the internal genes of two avian H9N2 viruses isolated from children in Hong Kong during 1999. PMID:10878047

  5. A Novel Activation Mechanism of Avian Influenza Virus H9N2 by Furin

    PubMed Central

    Tse, Longping V.; Hamilton, Alice M.; Friling, Tamar

    2014-01-01

    Avian influenza virus H9N2 is prevalent in waterfowl and has become endemic in poultry in Asia and the Middle East. H9N2 influenza viruses have served as a reservoir of internal genes for other avian influenza viruses that infect humans, and several cases of human infection by H9N2 influenza viruses have indicated its pandemic potential. Fortunately, an extensive surveillance program enables close monitoring of H9N2 influenza viruses worldwide and has generated a large repository of virus sequences and phylogenetic information. Despite the large quantity of sequences in different databases, very little is known about specific virus isolates and their pathogenesis. Here, we characterize a low-pathogenicity avian influenza virus, A/chicken/Israel/810/2001 (H9N2) (Israel810), which is representative of influenza virus strains that have caused severe morbidity and mortality in poultry farms. We show that under certain circumstances the Israel810 hemagglutinin (HA) can be activated by furin, a hallmark of highly pathogenic avian influenza virus. We demonstrate that Israel810 HA can be cleaved in cells with high levels of furin expression and that a mutation that eliminates a glycosylation site in HA1 allows the Israel810 HA to gain universal cleavage in cell culture. Pseudoparticles generated from Israel810 HA, or the glycosylation mutant, transduce cells efficiently. In contrast, introduction of a polybasic cleavage site into Israel810 HA leads to pseudoviruses that are compromised for transduction. Our data indicate a mechanism for an H9N2 evolutionary pathway that may allow it to gain virulence in a distinct manner from H5 and H7 influenza viruses. PMID:24257604

  6. Novel Highly Pathogenic Avian A(H5N2) and A(H5N8) Influenza Viruses of Clade 2.3.4.4 from North America Have Limited Capacity for Replication and Transmission in Mammals

    PubMed Central

    Kaplan, Bryan S.; Russier, Marion; Jeevan, Trushar; Marathe, Bindumadhav; Govorkova, Elena A.; Russell, Charles J.; Kim-Torchetti, Mia; Choi, Young Ki; Brown, Ian; Saito, Takehiko; Stallknecht, David E.; Krauss, Scott

    2016-01-01

    ABSTRACT Highly pathogenic influenza A(H5N8) viruses from clade 2.3.4.4 were introduced to North America by migratory birds in the fall of 2014. Reassortment of A(H5N8) viruses with avian viruses of North American lineage resulted in the generation of novel A(H5N2) viruses with novel genotypes. Through sequencing of recent avian influenza viruses, we identified PB1 and NP gene segments very similar to those in the viruses isolated from North American waterfowl prior to the introduction of A(H5N8) to North America, highlighting these bird species in the origin of reassortant A(H5N2) viruses. While they were highly virulent and transmissible in poultry, we found A(H5N2) viruses to be low pathogenic in mice and ferrets, and replication was limited in both hosts compared with those of recent highly pathogenic avian influenza (HPAI) H5N1 viruses. Molecular characterization of the hemagglutinin protein from A(H5N2) viruses showed that the receptor binding preference, cleavage, and pH of activation were highly adapted for replication in avian species and similar to those of other 2.3.4.4 viruses. In addition, North American and Eurasian clade 2.3.4.4 H5NX viruses replicated to significantly lower titers in differentiated normal human bronchial epithelial cells than did seasonal human A(H1N1) and highly pathogenic A(H5N1) viruses isolated from a human case. Thus, despite their having a high impact on poultry, our findings suggest that the recently emerging North American A(H5N2) viruses are not expected to pose a substantial threat to humans and other mammals without further reassortment and/or adaptation and that reassortment with North American viruses has not had a major impact on viral phenotype. IMPORTANCE Highly pathogenic H5 influenza viruses have been introduced into North America from Asia, causing extensive morbidity and mortality in domestic poultry. The introduced viruses have reassorted with North American avian influenza viruses, generating viral genotypes

  7. Novel Highly Pathogenic Avian A(H5N2) and A(H5N8) Influenza Viruses of Clade 2.3.4.4 from North America Have Limited Capacity for Replication and Transmission in Mammals.

    PubMed

    Kaplan, Bryan S; Russier, Marion; Jeevan, Trushar; Marathe, Bindumadhav; Govorkova, Elena A; Russell, Charles J; Kim-Torchetti, Mia; Choi, Young Ki; Brown, Ian; Saito, Takehiko; Stallknecht, David E; Krauss, Scott; Webby, Richard J

    2016-01-01

    Highly pathogenic influenza A(H5N8) viruses from clade 2.3.4.4 were introduced to North America by migratory birds in the fall of 2014. Reassortment of A(H5N8) viruses with avian viruses of North American lineage resulted in the generation of novel A(H5N2) viruses with novel genotypes. Through sequencing of recent avian influenza viruses, we identified PB1 and NP gene segments very similar to those in the viruses isolated from North American waterfowl prior to the introduction of A(H5N8) to North America, highlighting these bird species in the origin of reassortant A(H5N2) viruses. While they were highly virulent and transmissible in poultry, we found A(H5N2) viruses to be low pathogenic in mice and ferrets, and replication was limited in both hosts compared with those of recent highly pathogenic avian influenza (HPAI) H5N1 viruses. Molecular characterization of the hemagglutinin protein from A(H5N2) viruses showed that the receptor binding preference, cleavage, and pH of activation were highly adapted for replication in avian species and similar to those of other 2.3.4.4 viruses. In addition, North American and Eurasian clade 2.3.4.4 H5NX viruses replicated to significantly lower titers in differentiated normal human bronchial epithelial cells than did seasonal human A(H1N1) and highly pathogenic A(H5N1) viruses isolated from a human case. Thus, despite their having a high impact on poultry, our findings suggest that the recently emerging North American A(H5N2) viruses are not expected to pose a substantial threat to humans and other mammals without further reassortment and/or adaptation and that reassortment with North American viruses has not had a major impact on viral phenotype. IMPORTANCE Highly pathogenic H5 influenza viruses have been introduced into North America from Asia, causing extensive morbidity and mortality in domestic poultry. The introduced viruses have reassorted with North American avian influenza viruses, generating viral genotypes not seen on

  8. Characterization of cross protection of Swine-Origin Influenza Virus (S-OIV) H1N1 and reassortant H5N1 influenza vaccine in BALB/c mice given a single-dose vaccination

    PubMed Central

    2013-01-01

    Background Influenza virus has antigen drift and antigen shift effect, vaccination with some influenza vaccine might not induce sufficient immunity for host to the threat of other influenza virus strains. S-OIV H1N1 and H5N1 influenza vaccines in single-dose immunization were evaluated in mice for cross protection to the challenge of A/California/7/2009 H1N1 or NIBRG-14 H5N1 virus. Results Both H1N1 and H5N1 induced significant homologous IgG, HAI, and microneutralization antibody responses in the mice, while only vaccines plus adjuvant produced significant heterogeneous IgG and HAI antibody responses. Both alum and MPLA adjuvants significantly reduced the S-OIV H1N1 vaccine dose required to elicit protective HAI antibody titers from 0.05 μg to 0.001 μg. Vaccines alone did not protect mice from challenge with heterogeneous influenza virus, while H5N1 vaccine plus alum and MPLA adjuvants did. Mouse body weight loss was also less significant in the presence of adjuvant than in the vaccine without adjuvant. Furthermore, both H1N1 and H5N1 lung viral titers of immunized mice were significantly reduced post challenge with homologous viruses. Conclusion Only in the presence of MPLA adjuvant could the H5N1 vaccine significantly reduce mouse lung viral titers post H1N1 virus challenge, and not vice versa. MPLA adjuvant induced cross protection with a single dose vaccination to the challenge of heterogeneous influenza virus in mice. Lung viral titer seemed to be a better indicator compared to IgG, neutralization antibody, and HAI titer to predict survival of mice infected with influenza virus. PMID:23517052

  9. [Differences in oligomerization of nucleocapsid protein of epidemic human influenza A(H1N1), A(H1N2) and B viruses].

    PubMed

    Prokudina, E N; Semenova, N P; Chumakov, V M; Burtseva, E I; Slepushkin, A N

    2003-01-01

    A comparative analysis of involving the nucleocapsid protein (NP) into shaping-up of SDS-resistant oligomers was carried out presently in circulating epidemic strains of human influenza, viruses A and B. The study results of viral isolates obtained from clinical samples and recent standard strains revealed that the involvement of NP in the SDS-resistant oligomers, which are different in various subtypes of influenza A viruses. According to this sign, the human viruses A(9H3N2) are close to the avian ones, in which, as proved by us previously, virtually the entire NP transforms itself into the oligomers resistant to SDS. About 10-20% of NP are involved in shaping-up the virus influenza A(H1N1) of SDS-resistant oligomers. No SDS-resistant NP-oligomers were detected in influenza of type B. It is suggested that the prevalence of human viruses A(H3N2) in NP-oligomers are the peculiarities of NP structure and of the presence of the PB1 protein from avian influenza virus.

  10. Replication and transmission of mammalian-adapted H9 subtype influenza virus in pigs and quail

    USDA-ARS?s Scientific Manuscript database

    Influenza A is a major pathogen of birds, swine, and humans. Strains can jump from one species to another in a process that often requires genetic mutation and genome reassortment and results in outbreaks and, potentially, pandemics. H9N2 avian influenza is one of the most predominant influenza subt...

  11. Characterization of Monoclonal Antibodies against HA Protein of H1N1 Swine Influenza Virus and Protective Efficacy against H1 Viruses in Mice.

    PubMed

    Liu, Yun; Li, Hongtao; Xue, Yujia; Zhao, Shuang; Li, Chenxi; Qu, Liandong; Zhang, Yun; Liu, Ming

    2017-08-08

    H1N1 swine influenza viruses (SIV) are prevalent in pigs globally, and occasionally emerge in humans, which raises concern about their pandemic threats. To stimulate hemagglutination (HA) of A/Swine/Guangdong/LM/2004 (H1N1) (SW/GD/04) antibody response, eukaryotic expression plasmid pCI-neo-HA was constructed and used as an immunogen to prepare monoclonal antibodies (mAbs). Five mAbs (designed 8C4, 8C6, 9D6, 8A4, and 8B1) against HA protein were obtained and characterized. Western blot showed that the 70 kDa HA protein could be detected by all mAbs in MDCK cells infected with SW/GD/04. Three mAbs-8C4, 8C6, and 9D6-have hemagglutination inhibition (HI) and neutralization test (NT) activities, and 8C6 induces the highest HI and NT titers. The protection efficacy of 8C6 was investigated in BALB/c mice challenged with homologous or heterologous strains of the H1 subtype SIV. The results indicate that mAb 8C6 protected the mice from viral infections, especially the homologous strain, which was clearly demonstrated by the body weight changes and reduction of viral load. Thus, our findings document for the first time that mAb 8C6 might be of potential therapeutic value for H1 subtype SIV infection.

  12. Enhanced virulence of clade 2.3.2.1 highly pathogenic avian influenza A H5N1 viruses in ferrets.

    PubMed

    Pearce, Melissa B; Pappas, Claudia; Gustin, Kortney M; Davis, C Todd; Pantin-Jackwood, Mary J; Swayne, David E; Maines, Taronna R; Belser, Jessica A; Tumpey, Terrence M

    2017-02-01

    Sporadic avian to human transmission of highly pathogenic avian influenza (HPAI) A(H5N1) viruses necessitates the analysis of currently circulating and evolving clades to assess their potential risk. Following the spread and sustained circulation of clade 2 viruses across multiple continents, numerous subclades and genotypes have been described. To better understand the pathogenesis associated with the continued diversification of clade 2A(H5N1) influenza viruses, we investigated the relative virulence of eleven human and poultry isolates collected from 2006 to 2013 by determining their ability to cause disease in the ferret model. Numerous clade 2 viruses, including a clade 2.2 avian isolate, a 2.2.2.1 human isolate, and two 2.2.1 human isolates, were found to be of low virulence in the ferret model, though lethality was detected following infection with one 2.2.1 human isolate. In contrast, three of six clade 2.3.2.1 avian isolates tested led to severe disease and death among infected ferrets. Clade 2.3.2.1b and 2.3.2.1c isolates, but not 2.3.2.1a isolates, were associated with ferret lethality. All A(H5N1) viruses replicated efficiently in the respiratory tract of ferrets regardless of their virulence and lethality. However, lethal isolates were characterized by systemic viral dissemination, including detection in the brain and enhanced histopathology in lung tissues. The finding of disparate virulence phenotypes between clade 2A(H5N1) viruses, notably differences between subclades of 2.3.2.1 viruses, suggests there are distinct molecular determinants present within the established subclades, the identification of which will assist in molecular-based surveillance and public health efforts against A(H5N1) viruses. Published by Elsevier Inc.

  13. Enhanced virulence of clade 2.3.2.1 highly pathogenic avian influenza A H5N1 viruses in ferrets

    PubMed Central

    Pearce, Melissa B.; Pappas, Claudia; Gustin, Kortney M.; Davis, C. Todd; Pantin-Jackwood, Mary J.; Swayne, David E.; Maines, Taronna R.; Belser, Jessica A.; Tumpey, Terrence M.

    2017-01-01

    Sporadic avian to human transmission of highly pathogenic avian influenza (HPAI) A(H5N1) viruses necessitates the analysis of currently circulating and evolving clades to assess their potential risk. Following the spread and sustained circulation of clade 2 viruses across multiple continents, numerous subclades and genotypes have been described. To better understand the pathogenesis associated with the continued diversification of clade 2 A(H5N1) influenza viruses, we investigated the relative virulence of eleven human and poultry isolates collected from 2006 to 2013 by determining their ability to cause disease in the ferret model. Numerous clade 2 viruses, including a clade 2.2 avian isolate, a 2.2.2.1 human isolate, and two 2.2.1 human isolates, were found to be of low virulence in the ferret model, though lethality was detected following infection with one 2.2.1 human isolate. In contrast, three of six clade 2.3.2.1 avian isolates tested led to severe disease and death among infected ferrets. Clade 2.3.2.1b and 2.3.2.1c isolates, but not 2.3.2.1a isolates, were associated with ferret lethality. All A(H5N1) viruses replicated efficiently in the respiratory tract of ferrets regardless of their virulence and lethality. However, lethal isolates were characterized by systemic viral dissemination, including detection in the brain and enhanced histopathology in lung tissues. The finding of disparate virulence phenotypes between clade 2 A(H5N1) viruses, notably differences between subclades of 2.3.2.1 viruses, suggests there are distinct molecular determinants present within the established subclades, the identification of which will assist in molecular-based surveillance and public health efforts against A(H5N1) viruses. PMID:28038412

  14. Generation of a reassortant avian influenza virus H5N2 vaccine strain capable of protecting chickens against infection with Egyptian H5N1 and H9N2 viruses.

    PubMed

    Kandeil, Ahmed; Moatasim, Yassmin; Gomaa, Mokhtar R; Shehata, Mahmoud M; El-Shesheny, Rabeh; Barakat, Ahmed; Webby, Richard J; Ali, Mohamed A; Kayali, Ghazi

    2016-01-04

    Avian influenza H5N1 viruses have been enzootic in Egyptian poultry since 2006. Avian influenza H9N2 viruses which have been circulating in Egyptian poultry since 2011 showed high replication rates in embryonated chicken eggs and mammalian cells. To investigate which gene segment was responsible for increasing replication, we constructed reassortant influenza viruses using the low pathogenic H1N1 PR8 virus as backbone and included individual genes from A/chicken/Egypt/S4456B/2011(H9N2) virus. Then, we invested this finding to improve a PR8-derived H5N1 influenza vaccine strain by incorporation of the NA segment of H9N2 virus instead of the NA of H5N1. The growth properties of this virus and several other forms of reassortant H5 viruses were compared. Finally, we tested the efficacy of this reassortant vaccine strain in chickens. We observed an increase in replication for a reassortant virus expressing the neuraminidase gene (N2) of H9N2 virus relative to that of either parental viruses or reassortant PR8 viruses expressing other genes. Then, we generated an H5N2 vaccine strain based on the H5 from an Egyptian H5N1 virus and the N2 from an Egyptian H9N2 virus on a PR8 backbone. This strain had better replication rates than an H5N2 reassortant strain on an H9N2 backbone and an H5N1 reassortant on a PR8 backbone. This virus was then used to develop a killed, oil-emulsion vaccine and tested for efficacy against H5N1 and H9N2 viruses in chickens. Results showed that this vaccine was immunogenic and reduced mortality and shedding. Our findings suggest that an inactivated PR8-derived H5N2 influenza vaccine is efficacious in poultry against H5N1 and H9N2 viruses and the vaccine seed replicates at a high rate thus improving vaccine production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Evolution of the hemagglutinin expressed by human influenza A(H1N1)pdm09 and A(H3N2) viruses circulating between 2008-2009 and 2013-2014 in Germany.

    PubMed

    Wedde, Marianne; Biere, Barbara; Wolff, Thorsten; Schweiger, Brunhilde

    2015-10-01

    This report describes the evolution of the influenza A(H1N1)pdm09 and A(H3N2) viruses circulating in Germany between 2008-2009 and 2013-2014. The phylogenetic analysis of the hemagglutinin (HA) genes of both subtypes revealed similar evolution of the HA variants that were also seen worldwide with minor exceptions. The analysis showed seven distinct HA clades for A(H1N1)pdm09 and six HA clades for A(H3N2) viruses. Herald strains of both subtypes appeared sporadically since 2008-2009. Regarding A(H1N1)pdm09, herald strains of HA clade 3 and 4 were detected late in the 2009-2010 season. With respect to A(H3N2), we found herald strains of HA clade 3, 4 and 7 between 2009 and 2012. Those herald strains were predominantly seen for minor and not for major HA clades. Generally, amino acid substitutions were most frequently found in the globular domain, including substitutions near the antigenic sites or the receptor binding site. Differences between both influenza A subtypes were seen with respect to the position of the indicated substitutions in the HA. For A(H1N1)pdm09 viruses, we found more substitutions in the stem region than in the antigenic sites. In contrast, in A(H3N2) viruses most changes were identified in the major antigenic sites and five changes of potential glycosylation sites were identified in the head of the HA monomer. Interestingly, we found in seasons with less influenza activity a relatively high increase of substitutions in the head of the HA in both subtypes. This might be explained by the fact that mutations under negative selection are subsequently compensated by secondary mutations to restore important functions e.g. receptor binding properties. A better knowledge of basic evolution strategies of influenza viruses will contribute to the refinement of predictive mathematical models for identifying novel antigenic drift variants. Copyright © 2015 Elsevier GmbH. All rights reserved.

  16. Reassortant Clade 2.3.4.4 of Highly Pathogenic Avian Influenza A(H5N6) Virus, Taiwan, 2017.

    PubMed

    Chen, Li-Hsuan; Lee, Dong-Hun; Liu, Yu-Pin; Li, Wan-Chen; Swayne, David E; Chang, Jen-Chieh; Chen, Yen-Ping; Lee, Fan; Tu, Wen-Jane; Lin, Yu-Ju

    2018-06-01

    A highly pathogenic avian influenza A(H5N6) virus of clade 2.3.4.4 was detected in a domestic duck found dead in Taiwan during February 2017. The endemic situation and continued evolution of various reassortant highly pathogenic avian influenza viruses in Taiwan warrant concern about further reassortment and a fifth wave of intercontinental spread.

  17. Determinants of glycan receptor specificity of H2N2 influenza A virus hemagglutinin.

    PubMed

    Viswanathan, Karthik; Koh, Xiaoying; Chandrasekaran, Aarthi; Pappas, Claudia; Raman, Rahul; Srinivasan, Aravind; Shriver, Zachary; Tumpey, Terrence M; Sasisekharan, Ram

    2010-10-29

    The H2N2 subtype of influenza A virus was responsible for the Asian pandemic of 1957-58. However, unlike other subtypes that have caused pandemics such as H1N1 and H3N2, which continue to circulate among humans, H2N2 stopped circulating in the human population in 1968. Strains of H2 subtype still continue to circulate in birds and occasionally pigs and could be reintroduced into the human population through antigenic drift or shift. Such an event is a potential global health concern because of the waning population immunity to H2 hemagglutinin (HA). The first step in such a cross-species transmission and human adaptation of influenza A virus is the ability for its surface glycoprotein HA to bind to glycan receptors expressed in the human upper respiratory epithelia. Recent structural and biochemical studies have focused on understanding the glycan receptor binding specificity of the 1957-58 pandemic H2N2 HA. However, there has been considerable HA sequence divergence in the recent avian-adapted H2 strains from the pandemic H2N2 strain. Using a combination of structural modeling, quantitative glycan binding and human respiratory tissue binding methods, we systematically identify mutations in the HA from a recent avian-adapted H2N2 strain (A/Chicken/PA/2004) that make its quantitative glycan receptor binding affinity (defined using an apparent binding constant) comparable to that of a prototypic pandemic H2N2 (A/Albany/6/58) HA.

  18. Determinants of Glycan Receptor Specificity of H2N2 Influenza A Virus Hemagglutinin

    PubMed Central

    Chandrasekaran, Aarthi; Pappas, Claudia; Raman, Rahul; Srinivasan, Aravind; Shriver, Zachary; Tumpey, Terrence M.; Sasisekharan, Ram

    2010-01-01

    The H2N2 subtype of influenza A virus was responsible for the Asian pandemic of 1957-58. However, unlike other subtypes that have caused pandemics such as H1N1 and H3N2, which continue to circulate among humans, H2N2 stopped circulating in the human population in 1968. Strains of H2 subtype still continue to circulate in birds and occasionally pigs and could be reintroduced into the human population through antigenic drift or shift. Such an event is a potential global health concern because of the waning population immunity to H2 hemagglutinin (HA). The first step in such a cross-species transmission and human adaptation of influenza A virus is the ability for its surface glycoprotein HA to bind to glycan receptors expressed in the human upper respiratory epithelia. Recent structural and biochemical studies have focused on understanding the glycan receptor binding specificity of the 1957-58 pandemic H2N2 HA. However, there has been considerable HA sequence divergence in the recent avian-adapted H2 strains from the pandemic H2N2 strain. Using a combination of structural modeling, quantitative glycan binding and human respiratory tissue binding methods, we systematically identify mutations in the HA from a recent avian-adapted H2N2 strain (A/Chicken/PA/2004) that make its quantitative glycan receptor binding affinity (defined using an apparent binding constant) comparable to that of a prototypic pandemic H2N2 (A/Albany/6/58) HA. PMID:21060797

  19. The pig as a mixing vessel for influenza viruses: Human and veterinary implications

    PubMed Central

    Ma, Wenjun; Kahn, Robert E; Richt, Juergen A

    2009-01-01

    Influenza A viruses are highly infectious respiratory pathogens that can infect many species. Birds are the reservoir for all known influenza A subtypes; and novel influenza viruses can emerge from birds and infect mammalian species including humans. Because swine are susceptible to infection with both avian and human influenza viruses, novel reassortant influenza viruses can be generated in this mammalian species by reassortment of influenza viral segments leading to the “mixing vessel” theory. There is no direct evidence that the reassortment events culminating in the 1918, 1957 or 1968 pandemic influenza viruses originated from pigs. Genetic reassortment among avian, human and/or swine influenza virus gene segments has occurred in pigs and some novel reassortant swine viruses have been transmitted to humans. Notably, novel reassortant H2N3 influenza viruses isolated from the US pigs, most likely infected with avian influenza viruses through surface water collected in ponds for cleaning barns and watering animals, had a similar genetic make-up to early isolates (1957) of the H2N2 human pandemic. These novel H2N3 swine viruses were able to cause disease in swine and mice and were infectious and highly transmissible in swine and ferrets without prior adaptation. The preceding example shows that pigs could transmit novel viruses from an avian reservoir to other mammalian species. Importantly, H2 viruses pose a substantial risk to humans because they have been absent from mammalian species since 1968 and people born after 1968 have little preexisting immunity to the H2 subtype. It is difficult to predict which virus will cause the next human pandemic and when that pandemic might begin. Importantly, the establishment and spread of a reassorted mammalian-adapted virus from pigs to humans could happen anywhere in the world. Therefore, both human and veterinary research needs to give more attention to potential cross-species transmission capacity of influenza A

  20. Quantifying selection and diversity in viruses by entropy methods, with application to the haemagglutinin of H3N2 influenza

    PubMed Central

    Pan, Keyao; Deem, Michael W.

    2011-01-01

    Many viruses evolve rapidly. For example, haemagglutinin (HA) of the H3N2 influenza A virus evolves to escape antibody binding. This evolution of the H3N2 virus means that people who have previously been exposed to an influenza strain may be infected by a newly emerged virus. In this paper, we use Shannon entropy and relative entropy to measure the diversity and selection pressure by an antibody in each amino acid site of H3 HA between the 1992–1993 season and the 2009–2010 season. Shannon entropy and relative entropy are two independent state variables that we use to characterize H3N2 evolution. The entropy method estimates future H3N2 evolution and migration using currently available H3 HA sequences. First, we show that the rate of evolution increases with the virus diversity in the current season. The Shannon entropy of the sequence in the current season predicts relative entropy between sequences in the current season and those in the next season. Second, a global migration pattern of H3N2 is assembled by comparing the relative entropy flows of sequences sampled in China, Japan, the USA and Europe. We verify this entropy method by describing two aspects of historical H3N2 evolution. First, we identify 54 amino acid sites in HA that have evolved in the past to evade the immune system. Second, the entropy method shows that epitopes A and B on the top of HA evolve most vigorously to escape antibody binding. Our work provides a novel entropy-based method to predict and quantify future H3N2 evolution and to describe the evolutionary history of H3N2. PMID:21543352

  1. Kinetics of lung lesion development and pro-inflammatory cytokine response in pigs with vaccine-associated enhanced respiratory disease induced by challenge with pandemic (2009) A/H1N1 influenza virus

    USDA-ARS?s Scientific Manuscript database

    The objective of this report was to characterize the enhanced clinical disease and lung lesions observed in pigs vaccinated with inactivated H1N2 swine delta-cluster influenza A virus and challenged with pandemic 2009 A/H1N1 human influenza virus. Eighty-four, six-week-old, crossbred pigs were rand...

  2. The emergence and evolution of influenza A (H1α) viruses in swine in Canada and the United States

    PubMed Central

    Culhane, Marie R.; Trovão, Nídia S.; Patnayak, Devi P.; Halpin, Rebecca A.; Lin, Xudong; Shilts, Meghan H.; Das, Suman R.; Detmer, Susan E.

    2017-01-01

    Swine are a key reservoir host for influenza A viruses (IAVs), with the potential to cause global pandemics in humans. Gaps in surveillance in many of the world's largest swine populations impede our understanding of how novel viruses emerge and expand their spatial range in pigs. Although US swine are intensively sampled, little is known about IAV diversity in Canada's population of ~12 million pigs. By sequencing 168 viruses from multiple regions of Canada, our study reveals that IAV diversity has been underestimated in Canadian pigs for many years. Critically, a new H1 clade has emerged in Canada (H1α-3), with a two-amino acid deletion at H1 positions 146–147, that experienced rapid growth in Manitoba's swine herds during 2014–2015. H1α-3 viruses also exhibit a higher capacity to invade US swine herds, resulting in multiple recent introductions of the virus into the US Heartland following large-scale movements of pigs in this direction. From the Heartland, H1α-3 viruses have disseminated onward to both the east and west coasts of the United States, and may become established in Appalachia. These findings demonstrate how long-distance trading of live pigs facilitates the spread of IAVs, increasing viral genetic diversity and complicating pathogen control. The proliferation of novel H1α-3 viruses also highlights the need for expanded surveillance in a Canadian swine population that has long been overlooked, and may have implications for vaccine design. PMID:29058649

  3. Novel H7N2 and H5N6 Avian Influenza A Viruses in Sentinel Chickens: A Sentinel Chicken Surveillance Study.

    PubMed

    Zhao, Teng; Qian, Yan-Hua; Chen, Shan-Hui; Wang, Guo-Lin; Wu, Meng-Na; Huang, Yong; Ma, Guang-Yuan; Fang, Li-Qun; Gray, Gregory C; Lu, Bing; Tong, Yi-Gang; Ma, Mai-Juan; Cao, Wu-Chun

    2016-01-01

    In 2014, a sentinel chicken surveillance for avian influenza viruses was conducted in aquatic bird habitat near Wuxi City, Jiangsu Province, China. Two H7N2, one H5N6, and two H9N2 viruses were isolated. Sequence analysis revealed that the H7N2 virus is a novel reassortant of H7N9 and H9N2 viruses and H5N6 virus is a reassortant of H5N1 clade 2.3.4 and H6N6 viruses. Substitutions V186 and L226 (H3 numbering) in the hemagglutinin (HA) gene protein was found in two H7N2 viruses but not in the H5N6 virus. Two A138 and A160 mutations were identified in the HA gene protein of all three viruses but a P128 mutation was only observed in the H5N6 virus. A deletion of 3 and 11 amino acids in the neuraminidase stalk region was found in two H7N2 and H5N6 viruses, respectively. Moreover, a mutation of N31 in M2 protein was observed in both two H7N2 viruses. High similarity of these isolated viruses to viruses previously identified among poultry and humans, suggests that peridomestic aquatic birds may play a role in sustaining novel virus transmission. Therefore, continued surveillance is needed to monitor these avian influenza viruses in wild bird and domestic poultry that may pose a threat to poultry and human health.

  4. Mutation tryptophan to leucine at position 222 of haemagglutinin could facilitate H3N2 influenza A virus infection in dogs

    PubMed Central

    Yang, Guohua; Li, Shoujun; Blackmon, Sherry; Ye, Jianqiang; Bradley, Konrad C.; Cooley, Jim; Smith, Dave; Hanson, Larry; Cardona, Carol; Steinhauer, David A.; Webby, Richard; Liao, Ming

    2013-01-01

    An avian-like H3N2 influenza A virus (IAV) has recently caused sporadic canine influenza outbreaks in China and Korea, but the molecular mechanisms involved in the interspecies transmission of H3N2 IAV from avian to canine species are not well understood. Sequence analysis showed that residue 222 in haemagglutinin (HA) is predominantly tryptophan (W) in the closely related avian H3N2 IAV, but was leucine (L) in canine H3N2 IAV. In this study, reassortant viruses rH3N2-222L (canine-like) and rH3N2-222W (avian-like) with HA mutation L222W were generated using reverse genetics to evaluate the significance of the L222W mutation on receptor binding and host tropism of H3N2 IAV. Compared with rH3N2-222W, rH3N2-222L grew more rapidly in MDCK cells and had significantly higher infectivity in primary canine tracheal epithelial cells. Tissue-binding assays demonstrated that rH3N2-222L had a preference for canine tracheal tissues rather avian tracheal tissues, whereas rH3N2-222W favoured slightly avian rather canine tracheal tissues. Glycan microarray analysis suggested both rH3N2-222L and rH3N2-222W bound preferentially to α2,3-linked sialic acids. However, the rH3N2-222W had more than twofold less binding affinity than rH3N2-222L to a set of glycans with Neu5Aca23Galb1–4(Fuca-)-like or Neu5Aca23Galb1–3(Fuca-)-like structures. These data suggest the W to L mutation at position 222 of the HA could facilitate infection of H3N2 IAV in dogs, possibly by increasing the binding affinities of the HA to specific receptors with Neu5Aca23Galb1–4(Fuca-) or Neu5Aca23Galb1–3(Fuca-)-like structures that are present in dogs. PMID:23994833

  5. Antigenic characterization of H3 subtypes of avian influenza A viruses from North America

    USGS Publications Warehouse

    Bailey, Elizabeth; Long, Li-Pong; Zhao, Nan; Hall, Jeffrey S.; Baroch, John A; Nolting, Jaqueline; Senter, Lucy; Cunningham, Frederick L; Pharr, G Todd; Hanson, Larry; Slemons, Richard; DeLiberto, Thomas J.; Wan, Xiu-Feng

    2016-01-01

    Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

  6. Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America.

    PubMed

    Bailey, Elizabeth; Long, Li-Ping; Zhao, Nan; Hall, Jeffrey S; Baroch, John A; Nolting, Jacqueline; Senter, Lucy; Cunningham, Frederick L; Pharr, G Todd; Hanson, Larry; Slemons, Richard; DeLiberto, Thomas J; Wan, Xiu-Feng

    2016-05-01

    Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

  7. Novel Reassortant Clade 2.3.4.4 Avian Influenza A(H5N8) Virus in Wild Aquatic Birds, Russia, 2016.

    PubMed

    Lee, Dong-Hun; Sharshov, Kirill; Swayne, David E; Kurskaya, Olga; Sobolev, Ivan; Kabilov, Marsel; Alekseev, Alexander; Irza, Victor; Shestopalov, Alexander

    2017-02-01

    The emergence of novel avian influenza viruses in migratory birds is of concern because of the potential for virus dissemination during fall migration. We report the identification of novel highly pathogenic avian influenza viruses of subtype H5N8, clade 2.3.4.4, and their reassortment with other avian influenza viruses in waterfowl and shorebirds of Siberia.

  8. Detection and characterization of an H4N6 avian-lineage influenza A virus in pigs in the Midwestern United States

    USDA-ARS?s Scientific Manuscript database

    H4Nx viruses were reported in swine in Canada and China, but had not been recognized in swine in the USA. In late 2015, an avian-origin H4N6 influenza A virus was isolated from pigs in the United States during a routine diagnostic investigation of clinical respiratory disease in the herd. Serologica...

  9. Characterization of an H9N2 avian influenza virus from a Fringilla montifringilla brambling in northern China.

    PubMed

    Yuan, Jing; Xu, Lili; Bao, Linlin; Yao, Yanfeng; Deng, Wei; Li, Fengdi; Lv, Qi; Gu, Songzhi; Wei, Qiang; Qin, Chuan

    2015-02-01

    Avian H9N2 influenza viruses circulating in domestic poultry populations are occasionally transmitted to humans. We report the genomic characterization of an H9N2 avian influenza virus (A/Brambling/Beijing/16/2012) first isolated from a healthy Fringilla montifringilla brambling in northern China in 2012. Phylogenetic analyses revealed that this H9N2 virus belongs to the BJ/94-like sublineage. This virus had a low pathogenicity for chickens and was able to replicate at a low level in mouse lung tissue. Transmission studies in ferrets showed that this H9N2 strain shed high levels of the virus in nasal and throat swabs. In vitro receptor binding assays, the virus bound only to α-2,6 linkage receptors and not to the avian-type α-2,3 linkage receptors, suggesting that H9N2 influenza viruses present potential public health risks. Therefore, attention should be paid to H9N2 influenza viruses and the close surveillance of H9N2 viruses in poultry. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Global Migration Dynamics Underlie Evolution and Persistence of Human Influenza A (H3N2)

    PubMed Central

    Bedford, Trevor; Cobey, Sarah; Beerli, Peter; Pascual, Mercedes

    2010-01-01

    The global migration patterns of influenza viruses have profound implications for the evolutionary and epidemiological dynamics of the disease. We developed a novel approach to reconstruct the genetic history of human influenza A (H3N2) collected worldwide over 1998 to 2009 and used it to infer the global network of influenza transmission. Consistent with previous models, we find that China and Southeast Asia lie at the center of this global network. However, we also find that strains of influenza circulate outside of Asia for multiple seasons, persisting through dynamic migration between northern and southern regions. The USA acts as the primary hub of temperate transmission and, together with China and Southeast Asia, forms the trunk of influenza's evolutionary tree. These findings suggest that antiviral use outside of China and Southeast Asia may lead to the evolution of long-term local and potentially global antiviral resistance. Our results might also aid the design of surveillance efforts and of vaccines better tailored to different geographic regions. PMID:20523898

  11. Unifying viral genetics and human transportation data to predict the global transmission dynamics of human influenza H3N2.

    PubMed

    Lemey, Philippe; Rambaut, Andrew; Bedford, Trevor; Faria, Nuno; Bielejec, Filip; Baele, Guy; Russell, Colin A; Smith, Derek J; Pybus, Oliver G; Brockmann, Dirk; Suchard, Marc A

    2014-02-01

    Information on global human movement patterns is central to spatial epidemiological models used to predict the behavior of influenza and other infectious diseases. Yet it remains difficult to test which modes of dispersal drive pathogen spread at various geographic scales using standard epidemiological data alone. Evolutionary analyses of pathogen genome sequences increasingly provide insights into the spatial dynamics of influenza viruses, but to date they have largely neglected the wealth of information on human mobility, mainly because no statistical framework exists within which viral gene sequences and empirical data on host movement can be combined. Here, we address this problem by applying a phylogeographic approach to elucidate the global spread of human influenza subtype H3N2 and assess its ability to predict the spatial spread of human influenza A viruses worldwide. Using a framework that estimates the migration history of human influenza while simultaneously testing and quantifying a range of potential predictive variables of spatial spread, we show that the global dynamics of influenza H3N2 are driven by air passenger flows, whereas at more local scales spread is also determined by processes that correlate with geographic distance. Our analyses further confirm a central role for mainland China and Southeast Asia in maintaining a source population for global influenza diversity. By comparing model output with the known pandemic expansion of H1N1 during 2009, we demonstrate that predictions of influenza spatial spread are most accurate when data on human mobility and viral evolution are integrated. In conclusion, the global dynamics of influenza viruses are best explained by combining human mobility data with the spatial information inherent in sampled viral genomes. The integrated approach introduced here offers great potential for epidemiological surveillance through phylogeographic reconstructions and for improving predictive models of disease control.

  12. Illness representation on H1N1 influenza and preventive behaviors in the Hong Kong general population.

    PubMed

    Mo, Phoenix K H; Lau, Joseph T F

    2015-12-01

    This study examined illness representations of new influenza Human Swine Influenza A (H1N1) and association with H1N1 preventive behaviors among 300 Chinese adults using a population-based randomized telephone survey. Results showed that relatively few participants thought H1N1 would have serious consequences (12%-15.7%) and few showed negative emotional responses toward H1N1 (9%-24.7%). The majority of the participants thought H1N1 could be controlled by treatment (70.4%-72.7%). Multiple logistic regression analyses showed that treatment control (odds ratio = 1.78) and psychological attribution (odds ratio = .75) were associated with intention to take up influenza vaccination. Emotional representations were associated with lower likelihood of wearing face mask (odds ratio = .77) and hand washing (odds ratio = .67). Results confirm that illness representation variables are associated with H1N1 preventive behaviors. © The Author(s) 2014.

  13. Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil.

    PubMed

    Schmidt, C; Cibulski, S P; Andrade, C P; Teixeira, T F; Varela, A P M; Scheffer, C M; Franco, A C; de Almeida, L L; Roehe, P M

    2016-05-01

    Despite the putative endemic status of swine influenza A virus (swIAV) infections, data on the occurrence of swine influenza outbreaks are scarce in Brazil. The aim of this study was to detect and subtype swIAVs from six outbreaks of porcine respiratory disease complex (PRDC) in southern Brazil. Nasal swabs were collected from 66 piglets with signs of respiratory disease in six herds. Lung tissue samples were collected from six necropsied animals. Virus detection was performed by PCR screening and confirmed by virus isolation and hemagglutination (HA). Influenza A subtyping was performed by a real-time reverse transcriptase PCR (rRT-PCR) to detect the A(H1N1)pdm09; other swIAV subtypes were determined by multiplex RT-PCR. In lung tissues, the major bacterial and viral pathogens associated with PRDC (Pasteurella multocida, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and PCV2) were investigated. In some affected pigs, clinico-pathological evaluations were conducted. Influenza A was detected by screening PCR in 46 of 66 swab samples and from five of six lungs. Virus was recovered from pigs of all six herds. Subtype A(H1N1)pdm09 was detected in four of six herds and H1N2 in the other two herds. In lung tissues, further agents involved in PRDC were detected in all cases; Pasteurella multocida was identified in five of six samples and Mycoplasma hyopneumoniae in three of six. Actinobacillus pleuropneumoniae (1/6), Haemophilus parasuis (1/6) and PCV2 (1/6) were also detected. These findings indicate that subtypes A(H1N1)pdm09 and H1N2 were present in pigs in southern Brazil and were associated with PRDC outbreaks. © 2015 Blackwell Verlag GmbH.

  14. Experimental infection of highly pathogenic avian influenza viruses, Clade 2.3.4.4 H5N6 and H5N8, in Mandarin ducks from South Korea.

    PubMed

    Son, K; Kim, Y-K; Oem, J-K; Jheong, W-H; Sleeman, J M; Jeong, J

    2018-06-01

    Outbreaks of highly pathogenic avian influenza (HPAI) have been reported worldwide. Wild waterfowl play a major role in the maintenance and transmission of HPAI. Highly pathogenic avian influenza subtype H5N6 and H5N8 viruses simultaneously emerged in South Korea. In this study, the comparative pathogenicity and infectivity of Clade 2.3.4.4 Group B H5N8 and Group C H5N6 viruses were evaluated in Mandarin duck (Aix galericulata). None of the ducks infected with H5N6 or H5N8 viruses showed clinical signs or mortality. Serological assays revealed that the HA antigenicity of H5N8 and H5N6 viruses was similar to each other. Moreover, both the viruses did not replicate after cross-challenging with H5N8 and H5N6 viruses, respectively, as the second infection. Although both the viruses replicated in most of the internal organs of the ducks, viral replication and shedding through cloaca were higher in H5N8-infected ducks than in H5N6-infected ducks. The findings of this study provide preliminary information to help estimate the risks involved in further evolution and dissemination of Clade 2.3.4.4 HPAI viruses among wild birds. © 2017 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

  15. Incidence and Epidemiology of Hospitalized Influenza Cases in Rural Thailand during the Influenza A (H1N1)pdm09 Pandemic, 2009–2010

    PubMed Central

    Baggett, Henry C.; Chittaganpitch, Malinee; Thamthitiwat, Somsak; Prapasiri, Prabda; Naorat, Sathapana; Sawatwong, Pongpun; Ditsungnoen, Darunee; Olsen, Sonja J.; Simmerman, James M.; Srisaengchai, Prasong; Chantra, Somrak; Peruski, Leonard F.; Sawanpanyalert, Pathom; Maloney, Susan A.; Akarasewi, Pasakorn

    2012-01-01

    Background Data on the burden of the 2009 influenza pandemic in Asia are limited. Influenza A(H1N1)pdm09 was first reported in Thailand in May 2009. We assessed incidence and epidemiology of influenza-associated hospitalizations during 2009–2010. Methods We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infection (ALRI) in all 20 hospitals in two rural provinces. ALRI patients were sampled 1∶2 for participation in an etiology study in which nasopharyngeal swabs were collected for influenza virus testing by PCR. Results Of 7,207 patients tested, 902 (12.5%) were influenza-positive, including 190 (7.8%) of 2,436 children aged <5 years; 86% were influenza A virus (46% A(H1N1)pdm09, 30% H3N2, 6.5% H1N1, 3.5% not subtyped) and 13% were influenza B virus. Cases of influenza A(H1N1)pdm09 first peaked in August 2009 when 17% of tested patients were positive. Subsequent peaks during 2009 and 2010 represented a mix of influenza A(H1N1)pdm09, H3N2, and influenza B viruses. The estimated annual incidence of hospitalized influenza cases was 136 per 100,000, highest in ages <5 years (477 per 100,000) and >75 years (407 per 100,000). The incidence of influenza A(H1N1)pdm09 was 62 per 100,000 (214 per 100,000 in children <5 years). Eleven influenza-infected patients required mechanical ventilation, and four patients died, all adults with influenza A(H1N1)pdm09 (1) or H3N2 (3). Conclusions Influenza-associated hospitalization rates in Thailand during 2009–10 were substantial and exceeded rates described in western countries. Influenza A(H1N1)pdm09 predominated, but H3N2 also caused notable morbidity. Expanded influenza vaccination coverage could have considerable public health impact, especially in young children. PMID:23139802

  16. Personal protective equipment and risk for avian influenza (H7N3).

    PubMed

    Morgan, Oliver; Kuhne, Mirjam; Nair, Pat; Verlander, Neville Q; Preece, Richard; McDougal, Marianne; Zambon, Maria; Reacher, Mark

    2009-01-01

    An outbreak of avian influenza (H7N3) among poultry resulted in laboratory-confirmed disease in 1 of 103 exposed persons. Incomplete use of personal protective equipment (PPE) was associated with conjunctivitis and influenza-like symptoms. Rigorous use of PPE by persons managing avian influenza outbreaks may reduce exposure to potentially hazardous infected poultry materials.

  17. Personal Protective Equipment and Risk for Avian Influenza (H7N3)

    PubMed Central

    Kuhne, Mirjam; Nair, Pat; Verlander, Neville Q.; Preece, Richard; McDougal, Marianne; Zambon, Maria; Reacher, Mark

    2009-01-01

    An outbreak of avian influenza (H7N3) among poultry resulted in laboratory-confirmed disease in 1 of 103 exposed persons. Incomplete use of personal protective equipment (PPE) was associated with conjunctivitis and influenza-like symptoms. Rigorous use of PPE by persons managing avian influenza outbreaks may reduce exposure to potentially hazardous infected poultry materials. PMID:19116052

  18. Evidence for common ancestry among viruses isolated from wild birds in Beringia and highly pathogenic intercontinental reassortant H5N1 and H5N2 influenza A viruses

    USGS Publications Warehouse

    Ramey, Andy M.; Reeves, Andrew; Teslaa, Joshua L.; Nashold, Sean W.; Donnelly, Tyrone F.; Bahl, Justin; Hall, Jeffrey S.

    2016-01-01

    Highly pathogenic clade 2.3.4.4 H5N8, H5N2, and H5N1 influenza A viruses were first detected in wild, captive, and domestic birds in North America in November–December 2014. In this study, we used wild waterbird samples collected in Alaska prior to the initial detection of clade 2.3.4.4 H5 influenza A viruses in North America to assess the evidence for: (1) dispersal of highly pathogenic influenza A viruses from East Asia to North America by migratory birds via Alaska and (2) ancestral origins of clade 2.3.4.4 H5 reassortant viruses in Beringia. Although we did not detect highly pathogenic influenza A viruses in our sample collection from western Alaska, we did identify viruses that contained gene segments sharing recent common ancestry with intercontinental reassortant H5N2 and H5N1 viruses. Results of phylogenetic analyses and estimates for times of most recent common ancestry support migratory birds sampled in Beringia as maintaining viral diversity closely related to novel highly pathogenic influenza A virus genotypes detected in North America. Although our results do not elucidate the route by which highly pathogenic influenza A viruses were introduced into North America, genetic evidence is consistent with the hypothesized trans-Beringian route of introduction via migratory birds.

  19. Airborne Detection and Quantification of Swine Influenza A Virus in Air Samples Collected Inside, Outside and Downwind from Swine Barns

    PubMed Central

    Corzo, Cesar A.; Culhane, Marie; Dee, Scott; Morrison, Robert B.; Torremorell, Montserrat

    2013-01-01

    Airborne transmission of influenza A virus (IAV) in swine is speculated to be an important route of virus dissemination, but data are scarce. This study attempted to detect and quantify airborne IAV by virus isolation and RRT-PCR in air samples collected under field conditions. This was accomplished by collecting air samples from four acutely infected pig farms and locating air samplers inside the barns, at the external exhaust fans and downwind from the farms at distances up to 2.1 km. IAV was detected in air samples collected in 3 out of 4 farms included in the study. Isolation of IAV was possible from air samples collected inside the barn at two of the farms and in one farm from the exhausted air. Between 13% and 100% of samples collected inside the barns tested RRT-PCR positive with an average viral load of 3.20E+05 IAV RNA copies/m3 of air. Percentage of exhaust positive air samples also ranged between 13% and 100% with an average viral load of 1.79E+04 RNA copies/m3 of air. Influenza virus RNA was detected in air samples collected between 1.5 and 2.1 Km away from the farms with viral levels significantly lower at 4.65E+03 RNA copies/m3. H1N1, H1N2 and H3N2 subtypes were detected in the air samples and the hemagglutinin gene sequences identified in the swine samples matched those in aerosols providing evidence that the viruses detected in the aerosols originated from the pigs in the farms under study. Overall our results indicate that pigs can be a source of IAV infectious aerosols and that these aerosols can be exhausted from pig barns and be transported downwind. The results from this study provide evidence of the risk of aerosol transmission in pigs under field conditions. PMID:23951164

  20. Transmission potential of influenza A/H7N9, February to May 2013, China

    PubMed Central

    2013-01-01

    transmission potential of A/H7N9 appears lower than that of recent zoonotic threats, including avian influenza A/H5N1, swine influenza H3N2sw and Nipah virus. Conclusion Although uncertainty remains high in R estimates for H7N9 due to limited epidemiological information, all available evidence points to a low transmission potential. Continued monitoring of the transmission potential of A/H7N9 is critical in the coming months as intervention measures may be relaxed and seasonal factors could promote disease transmission in colder months. PMID:24083506