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Sample records for h3n2 swine influenza

  1. 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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Neutralizing DNA Aptamers against Swine Influenza H3N2 Viruses

    PubMed Central

    Wongphatcharachai, Manoosak; Wang, Ping; Enomoto, Shinichiro; Webby, Richard J.; Gramer, Marie R.; Amonsin, Alongkorn

    2013-01-01

    Triple reassortant influenza A viruses (IAVs) of swine, particularly the North American H3N2 subtype, circulate in swine herds and may reassort and result in the emergence of novel zoonotic strains. Current diagnostic tools rely on isolation of the viruses, followed by serotyping by hemagglutination or genome sequencing, both of which can be expensive and time-consuming. Thus, novel subtype-specific ligands and methods are needed for rapid testing and subtyping of IAVs in the field. To address this need, we selected DNA aptamers against the recombinant HA protein from swine IAV H3 cluster IV using systematic evolution of ligands by exponential enrichment (SELEX). Four candidate aptamers (HA68, HA7, HA2a, and HA2b) were identified and characterized. The dissociation constants (Kd) of aptamers HA68, HA7, HA2a, and HA2b against recombinant H3 protein were 7.1, 22.3, 16.0, and 3.7 nM, respectively. The binding site of HA68 to H3 was identified to be between nucleotide residues 8 and 40. All aptamers inhibited H3 hemagglutination. HA68 was highly specific to all four lineages within the North American H3N2 subtype. Further, the other three aptamers specifically identified live viruses belonging to the phylogenetic clusters I, II/III, and IV especially the virus that closely related to the recent H3N2 variant (H3N2v). Aptamer HA68 was also able to bind and detect H3N2v isolated from recent human cases. In conclusion, we provide subtype-specific aptamers against H3N2 IAVs of swine that can now be used in rapid detection and typing protocols for field applications. PMID:23077124

  4. 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.

  5. Lower seroreactivity to European than to North American H3N2 swine influenza viruses in humans, Luxembourg, 2010.

    PubMed

    Qiu, Y; Muller, C P; Van Reeth, K

    2015-01-01

    Seroreactivity to H3N2 swine influenza viruses (SIVs)was evaluated in serum samples collected from 843 people aged 0 to 100 years in 2010 in Luxembourg.Sera were analysed by haemagglutination inhibition(HI) and virus neutralisation (VN) assays targeting a European H3N2 SIV, a North American H3N2 variant of swine origin (H3N2v) and human seasonal H3N2 viruses isolated in 1975, 1995 and 2005. HI antibodies(titre ≥ 10) against European H3N2 SIV were almost exclusively detected in those born before 1990, of whom 70% were seropositive. HI antibodies against H3N2v were predominantly found in those born before 2000, with 86% seropositive. Titres against the North American H3N2v were higher than against the European H3N2 SIV. VN patterns were similar, but with higher rates and titres. We also demonstrated lower seroreactivity to European H3N2 SIV than to North American H3N2v virus. Finally, we found a strong correlation between HI titres against the European H3N2SIV and H3N2v and their respective human ancestors,A/Victoria/3/75 and A/Nanchang/933/95. This finding and the minimal contacts between humans and pigs in Luxembourg suggest that anti-SIV antibodies inhuman serum samples reflect serological cross-reactivity with historical human H3N2 viruses. Our findings help assess the pandemic risk of H3N2 SIV. PMID:25860393

  6. Lower seroreactivity to European than to North American H3N2 swine influenza viruses in humans, Luxembourg, 2010.

    PubMed

    Qiu, Y; Muller, C P; Van Reeth, K

    2015-04-02

    Seroreactivity to H3N2 swine influenza viruses (SIVs)was evaluated in serum samples collected from 843 people aged 0 to 100 years in 2010 in Luxembourg.Sera were analysed by haemagglutination inhibition(HI) and virus neutralisation (VN) assays targeting a European H3N2 SIV, a North American H3N2 variant of swine origin (H3N2v) and human seasonal H3N2 viruses isolated in 1975, 1995 and 2005. HI antibodies(titre ≥ 10) against European H3N2 SIV were almost exclusively detected in those born before 1990, of whom 70% were seropositive. HI antibodies against H3N2v were predominantly found in those born before 2000, with 86% seropositive. Titres against the North American H3N2v were higher than against the European H3N2 SIV. VN patterns were similar, but with higher rates and titres. We also demonstrated lower seroreactivity to European H3N2 SIV than to North American H3N2v virus. Finally, we found a strong correlation between HI titres against the European H3N2SIV and H3N2v and their respective human ancestors,A/Victoria/3/75 and A/Nanchang/933/95. This finding and the minimal contacts between humans and pigs in Luxembourg suggest that anti-SIV antibodies inhuman serum samples reflect serological cross-reactivity with historical human H3N2 viruses. Our findings help assess the pandemic risk of H3N2 SIV.

  7. 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.

  8. 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

  9. Subcellular proteomic analysis of human host cells infected with H3N2 swine influenza virus.

    PubMed

    Wu, Xiaopeng; Wang, Sanying; Yu, Yang; Zhang, Jinyang; Sun, Zeyu; Yan, Yan; Zhou, Jiyong

    2013-11-01

    Cross-species transmissions of swine influenza viruses (SIVs) raise great public health concerns. In this study, subcellular proteomic profiles of human A549 cells inoculated with H3N2 subtype SIV were used to characterize dynamic cellular responses to infection. By 2DE and MS, 27 differentially expressed (13 upregulated, 14 downregulated) cytoplasmic proteins and 20 differentially expressed (13 upregulated, 7 downregulated) nuclear proteins were identified. Gene ontology analysis suggested that these differentially expressed proteins were mainly involved in cell death, stress response, lipid metabolism, cell signaling, and RNA PTMs. Moreover, 25 corresponding genes of the differentially expressed proteins were quantitated by real time RT-PCR to examine the transcriptional profiles between mock- and virus-infected A549 cells. Western blot analysis confirmed that changes in abundance of identified cellular proteins heterogeneous nuclear ribonucleoprotein (hnRNP) U, hnRNP C, ALDH1A1, tryptophanyl-tRNA synthetase, IFI35, and HSPB1 in H3N2 SIV-infected cells were consistent with results of 2DE analysis. By confocal microscopy, nucleus-to-cytoplasm translocation of hnRNP C and colocalization between the viral nonstructural protein 1 and hnRNP C as well as N-myc (and STAT) interactor were observed upon infection. Ingenuity Pathway Analysis revealed that cellular proteins altered during infection were grouped mainly into NFκB and interferon signaling networks. Collectively, these identified subcellular constituents provide an important framework for understanding host/SIV interactions and underlying mechanisms of SIV cross-species infection and pathogenesis.

  10. Polymerase discordance in novel swine influenza H3N2v constellations is tolerated in swine but not human respiratory epithelial cells.

    PubMed

    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.

  11. [Characterization of M2 gene of H3N2 subtype swine influenza virus].

    PubMed

    Wang, Xiaodu; Chen, Peijun; Shen, Yang; Qiu, Yafeng; Deng, Xufang; Shi, Zixue; Peng, Lina; Luo, Jinyan; Liu, Chao; Ma, Zhiyong

    2010-01-01

    M2 protein of influenza A virus is encoded by a spliced mRNA derived from RNA segment 7 and plays an important role in influenza virus replication. It is also a target molecule of anti-virus drugs. We extracted the viral genome RNAs from MDCK cells infected with swine influenza A virus (SIV) H3N2 subtype and amplified the SIV M2 gene by reverse transcriptase-polymerase chain reaction using the isloated viral genome RNAs as template. The amplified cDNA was cloned into a prokaryotic expression vector pET-28a(+) (designated pET-28a(+)-M2) and a eukaryotic expression vector p3xFLAG-CMV-7.1 (designated p3xFLAG-CMV-7.1-M2), respectively. The resulted constructs were confirmed by restriction enzyme digestion and DNA sequencing analysis. We then transformed the plasmid pET-28a(+)-M2 into Escherichia coli BL21 (DE3) strain and expressed it by adding 1 mmol/L of IPTG (isopropyl-beta-D-thiogalactopyranoside). The recombinant M2 protein was purified from the induced bacterial cells using Ni(2+) affinity chromatography. Wistar rats were immunized with the purified M2 protein for producing polyclonal antibodies specific for it. Western blotting analysis and immunofluorescence analysis showed that the produced antibodies were capable of reacting with M2 protein expressed in p3xFLAG-CMV-7.1-M2-transfected cells as well as that synthesized in SIV-infected cells. We also transfected plasmid p3xFLAG-CMV-7.1-M2 into Vero cells and analyzed its subcellular localization by immunofluorescence. The M2 protein expressed in the Vero cells was 20 kDa in size and dominantly localized in the cytoplasm, showing a similar distribution to that in SIV-infected cells. Western blotting analysis of SIV-infected cells suggested that M2 was a late phase protein, which was detectable 12 h post-infection, later than NS1, NP and M1 proteins. It would be a potential molecular indicator of late phases replication of virus. Our results would be useful for studying the biological function of M2 protein in SIV

  12. Phylogenetic analysis of a swine influenza A(H3N2) virus isolated in Korea in 2012.

    PubMed

    Kim, Jin Il; Lee, Ilseob; 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.

  13. Antigenically intact hemagglutinin in circulating avian and swine influenza viruses and potential for H3N2 pandemic.

    PubMed

    Tharakaraman, Kannan; Raman, Rahul; Stebbins, Nathan W; Viswanathan, Karthik; Sasisekharan, Viswanathan; Sasisekharan, Ram

    2013-01-01

    The 2009 swine-origin H1N1 influenza, though antigenically novel to the population at the time, was antigenically similar to the 1918 H1N1 pandemic influenza, and consequently was considered to be "archived" in the swine species before reemerging in humans. Given that the H3N2 is another subtype that currently circulates in the human population and is high on WHO pandemic preparedness list, we assessed the likelihood of reemergence of H3N2 from a non-human host. Using HA sequence features relevant to immune recognition, receptor binding and transmission we have identified several recent H3 strains in avian and swine that present hallmarks of a reemerging virus. IgG polyclonal raised in rabbit with recent seasonal vaccine H3 fail to recognize these swine H3 strains suggesting that existing vaccines may not be effective in protecting against these strains. Vaccine strategies can mitigate risks associated with a potential H3N2 pandemic in humans.

  14. 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

  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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Unseasonal transmission of H3N2 influenza A virus during the swine-origin H1N1 pandemic.

    PubMed

    Ghedin, Elodie; Wentworth, David E; Halpin, Rebecca A; Lin, Xudong; Bera, Jayati; DePasse, Jay; Fitch, Adam; Griesemer, Sara; Hine, Erin; Katzel, Daniel A; Overton, Larry; Proudfoot, Kathleen; Sitz, Jeffrey; Szczypinski, Bridget; StGeorge, Kirsten; Spiro, David J; Holmes, Edward C

    2010-06-01

    The initial wave of swine-origin influenza A virus (pandemic H1N1/09) in the United States during the spring and summer of 2009 also resulted in an increased vigilance and sampling of seasonal influenza viruses (H1N1 and H3N2), even though they are normally characterized by very low incidence outside of the winter months. To explore the nature of virus evolution during this influenza "off-season," we conducted a phylogenetic analysis of H1N1 and H3N2 sequences sampled during April to June 2009 in New York State. Our analysis revealed that multiple lineages of both viruses were introduced and cocirculated during this time, as is typical of influenza virus during the winter. Strikingly, however, we also found strong evidence for the presence of a large transmission chain of H3N2 viruses centered on the south-east of New York State and which continued until at least 1 June 2009. These results suggest that the unseasonal transmission of influenza A viruses may be more widespread than is usually supposed.

  17. A Newly Emerged Swine-Origin Influenza A(H3N2) Variant Dampens Host Antiviral Immunity but Induces Potent Inflammasome Activation.

    PubMed

    Cao, Weiping; Mishina, Margarita; Ranjan, Priya; De La Cruz, Juan A; Kim, Jin Hyang; Garten, Rebecca; Kumar, Amrita; García-Sastre, Adolfo; Katz, Jacqueline M; Gangappa, Shivaprakash; Sambhara, Suryaprakash

    2015-12-15

    We compared the innate immune response to a newly emerged swine-origin influenza A(H3N2) variant containing the M gene from 2009 pandemic influenza A(H1N1), termed "A(H3N2)vpM," to the immune responses to the 2010 swine-origin influenza A(H3N2) variant and seasonal influenza A(H3N2). Our results demonstrated that A(H3N2)vpM-induced myeloid dendritic cells secreted significantly lower levels of type I interferon (IFN) but produced significantly higher levels of proinflammatory cytokines and induced potent inflammasome activation. The reduction in antiviral immunity with increased inflammatory responses upon A(H3N2)vpM infection suggest that these viruses have the potential for increased disease severity in susceptible hosts. PMID:26068782

  18. The growing diversity of H3N2 influenza A virus in swine and the impact on control in swine and at the human animal interface

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. H3N2 influenza A viruses (IAV) were recognized as endemic infections in the USA swine population following the 1997-98 incursion of the triple reassortant viruses with gene segments from human- (HA, NA, and PB1), swine- (NP, M, and NS) and avian- (PB2 and PA) adapted viruses (reviewed ...

  19. Mutation from arginine to lysine at the position 189 of hemagglutinin contributes to the antigenic drift in H3N2 swine influenza viruses.

    PubMed

    Ye, Jianqiang; Xu, Yifei; Harris, Jillian; Sun, Hailiang; Bowman, Andrew S; Cunningham, Fred; Cardona, Carol; Yoon, Kyoungjin J; Slemons, Richard D; Wan, Xiu-Feng

    2013-11-01

    Two distinct antigenic clusters were previously identified among the H3N2 swine influenza A viruses (IAVs) and were designated H3N2SIV-alpha and H3N2SIV-beta (Feng et al., 2013. Journal of Virology 87 (13), 7655-7667). A consistent mutation was observed at the position 189 of hemagglutinin (R189K) between H3N2SIV-alpha and H3N2SIV-beta fair isolates. To evaluate the contribution of R189K mutation to the antigenic drift from H3N2SIV-alpha to H3N2SIV-beta, four reassortant viruses with 189R or 189K were generated. The antigenic cartography demonstrated that the R189K mutation in the hemagglutinin of H3N2 IAV contributed to the antigenic drift, separating these viruses into H3N2SIV-alpha to H3N2SIV-beta. This R189K mutation was also found to contribute to the cross-reaction with several ferret sera raised against historical human IAVs with hemagglutinin carrying 189K. This study suggests that the R189K mutation plays a vital role in the antigenicity of swine and human H3N2 IAVs and identification of this antigenic determinant will help us rapidly identify antigenic variants in influenza surveillance.

  20. Phylogeography of Swine Influenza H3N2 in the United States: Translational Public Health for Zoonotic Disease Surveillance

    PubMed Central

    Scotch, Matthew; Mei, Changjiang

    2012-01-01

    The field of phylogeography has received a lot of attention for its application to molecular evolution and geographic migration of species. More recent work has included infectious diseases especially zoonotic RNA viruses like influenza and rabies. Phylogeography of viruses has the potential to advance surveillance at agencies such as public health departments, agriculture departments, and wildlife agencies. However, little is known about how these agencies could use phylogeography for applied surveillance and the integration of animal and human sequence data. Here, we highlight its potential to support ‘translational public health’ that could bring sequence data to the forefront of surveillance. We focus on swine influenza H3N2 because of the recent link to a variant form in humans. We discuss the implications to applied surveillance and the need for an integrated biomedical informatics approach for adoption at agencies of animal and public health. PMID:23137647

  1. Isolation of novel triple-reassortant swine H3N2 influenza viruses possessing the hemagglutinin and neuraminidase genes of a seasonal influenza virus in Vietnam in 2010.

    PubMed

    Ngo, Long Thanh; Hiromoto, Yasuaki; Pham, Vu Phong; Le, Ha Thi Hong; Nguyen, Ha Truc; Le, Vu Tri; Takemae, Nobuhiro; Saito, Takehiko

    2012-01-01

    Surveillance of swine influenza viruses (SIVs) in 31 pig farms in northern and southern parts of Vietnam was conducted. Six H3N2 influenza A viruses were isolated from a pig farm in southern Vietnam. They were novel genetic reassortants between a triple-reassortant SIV and a human seasonal H3N2 virus. Their hemagglutinin and neuraminidase genes were derived from a human virus circulating around 2004-2006 and the remaining genes from a triple-reassortant SIV that originated in North America. This is the first report describing the isolation of a novel triple-reassortant SIV in Vietnam.

  2. Detection of Novel Reassortant Influenza A (H3N2) and H1N1 2009 Pandemic Viruses in Swine in Hanoi, Vietnam.

    PubMed

    Baudon, E; Poon, L L; Dao, T D; Pham, N T; Cowling, B J; Peyre, M; Nguyen, K V; Peiris, M

    2015-09-01

    From May to September 2013, monthly samples were collected from swine in a Vietnamese slaughterhouse for influenza virus isolation and serological testing. A(H1N1)pdm09 viruses and a novel H3N2 originating from reassortment between A(H1N1)pdm09 and novel viruses of the North American triple reassortant lineage were isolated. Serological results showed low seroprevalence for the novel H3N2 virus and higher seroprevalence for A(H1N1)pdm09 viruses. In addition, serology suggested that other swine influenza viruses are also circulating in Vietnamese swine.

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

    PubMed

    2011-09-01

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  5. 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.

  6. Antigenic characterization of an H3N2 swine influenza virus isolated from pigs with proliferative and necrotizing pneumonia in Quebec.

    PubMed Central

    Bikour, M H; Cornaglia, E; Weber, J M; Elazhary, Y

    1994-01-01

    A new strain of swine influenza A virus, designated A/Swine/Saint-Hyacinthe/150/90 has been isolated from pigs with severe proliferative and necrotizing pneumonia in Quebec. The antigenic characterization of the hemagglutinin was performed by hemagglutination inhibition test, immunoblot and indirect immunoprecipitation using polyclonal antisera. Only the last test was able to detect an antigenic relationship between the hemagglutinin of this isolate and an H3 subtype influenza virus. The immunoprecipitation test was a useful alternative for determining the hemagglutinin of influenza A virus subtypes. The neuraminidase inhibition test demonstrated a reactivity between the A/Swine/Saint-Hyacinthe/150/90 and antiserum against a N2 subtype influenza virus. Our results indicate that this new strain isolated for the first time in the porcine population of Canada is related to A/Sw/Hong Kong/76 H3N2 swine influenza virus. Images Fig. 1. Fig. 2. PMID:7889461

  7. High genetic and antigenic similarity between a swine H3N2 influenza A virus and a prior human influenza vaccine virus: a possible immune pressure-driven cross-species transmission.

    PubMed

    Pan, Chungen; Wang, Guiping; Liao, Ming; Zhang, Gui-Hong; Jiang, Shibo

    2009-07-31

    In late April of 2009, a global outbreak of human influenza was reported. The causative agent is a highly unusual reassortant H1N1 influenza virus carrying genetic segments derived from swine, human and avian influenza viruses. In this study, we compared the HA, NA and other gene segments of a swine H3N2 influenza A virus, A/Swine/Guangdong/z5/2003, which was isolated from pigs in 2003 in Guangdong Province, China, to the predominant human and swine H3N2 viruses. We found that the similarity of gene segments of A/Swine/Guangdong/z5/2003 was closer to Moscow/99-like human H3N2 virus than Europe swine H3N2 viruses during 1999-2002. These results suggest that A/Swine/Guangdong/z5/2003 may be porcine in origin, possibly being driven by human immune pressure induced by either natural H3N2 virus infection or use of A/Moscow/10/99 (H3N2)-based human influenza vaccine. The results further confirm that swine may play a dual role as a "shelter" for hosting influenza virus from humans or birds and as a "mixing vessel" for generating reassortant influenza viruses, such as the one causing current influenza pandemic.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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)...

  9. 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

  10. Population susceptibility to a variant swine-origin influenza virus A(H3N2) in Vietnam, 2011-2012.

    PubMed

    Hoa, L N M; Bryant, J E; Choisy, M; Nguyet, L A; Bao, N T; Trang, N H; Chuc, N T K; Toan, T K; Saito, T; Takemae, N; Horby, P; Wertheim, H; Fox, A

    2015-10-01

    A reassortant swine-origin A(H3N2) virus (A/swine/BinhDuong/03-9/2010) was detected through swine surveillance programmes in southern Vietnam in 2010. This virus contains haemagglutinin and neuraminidase genes from a human A(H3N2) virus circulating around 2004-2006, and the internal genes from triple-reassortant swine influenza A viruses (IAVs). To assess population susceptibility to this virus we measured haemagglutination inhibiting (HI) titres to A/swine/BinhDuong/03-9/2010 and to seasonal A/Perth/16/2009 for 947 sera collected from urban and rural Vietnamese people during 2011-2012. Seroprevalence (HI ⩾ 40) was high and similar for both viruses, with 62·6% [95% confidence interval (CI) 59·4-65·7] against A/Perth/16/2009 and 54·6% (95% CI 51·4-57·8%) against A/swine/BinhDuong/03-9/2010, and no significant differences between urban and rural participants. Children aged <5 years lacked antibodies to the swine origin H3 virus despite high seroprevalence for A/Perth/16/2009. These results reveal vulnerability to infection to this contemporary swine IAV in children aged <5 years; however, cross-reactive immunity in adults would likely limit epidemic emergence potential. PMID:25761949

  11. Population susceptibility to a variant swine-origin influenza virus A(H3N2) in Vietnam, 2011-2012.

    PubMed

    Hoa, L N M; Bryant, J E; Choisy, M; Nguyet, L A; Bao, N T; Trang, N H; Chuc, N T K; Toan, T K; Saito, T; Takemae, N; Horby, P; Wertheim, H; Fox, A

    2015-10-01

    A reassortant swine-origin A(H3N2) virus (A/swine/BinhDuong/03-9/2010) was detected through swine surveillance programmes in southern Vietnam in 2010. This virus contains haemagglutinin and neuraminidase genes from a human A(H3N2) virus circulating around 2004-2006, and the internal genes from triple-reassortant swine influenza A viruses (IAVs). To assess population susceptibility to this virus we measured haemagglutination inhibiting (HI) titres to A/swine/BinhDuong/03-9/2010 and to seasonal A/Perth/16/2009 for 947 sera collected from urban and rural Vietnamese people during 2011-2012. Seroprevalence (HI ⩾ 40) was high and similar for both viruses, with 62·6% [95% confidence interval (CI) 59·4-65·7] against A/Perth/16/2009 and 54·6% (95% CI 51·4-57·8%) against A/swine/BinhDuong/03-9/2010, and no significant differences between urban and rural participants. Children aged <5 years lacked antibodies to the swine origin H3 virus despite high seroprevalence for A/Perth/16/2009. These results reveal vulnerability to infection to this contemporary swine IAV in children aged <5 years; however, cross-reactive immunity in adults would likely limit epidemic emergence potential.

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

    PubMed Central

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

    2010-01-01

    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. PMID:20484565

  13. 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.

  14. 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.

  15. Innate immune response to a H3N2 subtype swine influenza virus in newborn porcine trachea cells, alveolar macrophages, and precision-cut lung slices.

    PubMed

    Delgado-Ortega, Mario; Melo, Sandrine; Punyadarsaniya, Darsaniya; Ramé, Christelle; Olivier, Michel; Soubieux, Denis; Marc, Daniel; Simon, Gaëlle; Herrler, Georg; Berri, Mustapha; Dupont, Joëlle; Meurens, François

    2014-01-01

    Viral respiratory diseases remain of major importance in swine breeding units. Swine influenza virus (SIV) is one of the main known contributors to infectious respiratory diseases. The innate immune response to swine influenza viruses has been assessed in many previous studies. However most of these studies were carried out in a single-cell population or directly in the live animal, in all its complexity. In the current study we report the use of a trachea epithelial cell line (newborn pig trachea cells - NPTr) in comparison with alveolar macrophages and lung slices for the characterization of innate immune response to an infection by a European SIV of the H3N2 subtype. The expression pattern of transcripts involved in the recognition of the virus, interferon type I and III responses, and the host-response regulation were assessed by quantitative PCR in response to infection. Some significant differences were observed between the three systems, notably in the expression of type III interferon mRNA. Then, results show a clear induction of JAK/STAT and MAPK signaling pathways in infected NPTr cells. Conversely, PI3K/Akt signaling pathways was not activated. The inhibition of the JAK/STAT pathway clearly reduced interferon type I and III responses and the induction of SOCS1 at the transcript level in infected NPTr cells. Similarly, the inhibition of MAPK pathway reduced viral replication and interferon response. All together, these results contribute to an increased understanding of the innate immune response to H3N2 SIV and may help identify strategies to effectively control SIV infection. PMID:24712747

  16. 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

  17. Divergent immune responses and disease outcomes in piglets immunized with inactivated and attenuated H3N2 swine influenza vaccines in the presence of maternally-derived antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine-associated enhanced respiratory disease (VAERD) can occur in pigs given whole-inactivated virus (WIV) influenza vaccine upon infection with an antigenically divergent virus. VAERD was first characterized with H1 viruses, and later described in pigs vaccinated with H3N2 WIV and challenged wit...

  18. Recognition of influenza H3N2 variant virus by human neutralizing antibodies

    PubMed Central

    Bangaru, Sandhya; Nieusma, Travis; Kose, Nurgun; Thornburg, Natalie J.; Kaplan, Bryan S.; King, Hannah G.; Singh, Vidisha; Lampley, Rebecca M.; Cisneros, Alberto; Edwards, Kathryn M.; Edupuganti, Srilatha; Lai, Lilin; Richt, Juergen A.; Webby, Richard J.; Ward, Andrew B.; Crowe, James E.

    2016-01-01

    Since 2011, over 300 human cases of infection, especially in exposed children, with the influenza A H3N2 variant (H3N2v) virus that circulates in swine in the US have been reported. The structural and genetic basis for the lack of protection against H3N2v induced by vaccines containing seasonal H3N2 antigens is poorly understood. We isolated 17 human monoclonal antibodies (mAbs) that neutralized H3N2v virus from subjects experimentally immunized with an H3N2v candidate vaccine. Six mAbs exhibited very potent neutralizing activity (IC50 < 200 ng/ml) against the H3N2v virus but not against current human H3N2 circulating strains. Fine epitope mapping and structural characterization of antigen-antibody complexes revealed that H3N2v specificity was attributable to amino acid polymorphisms in the 150-loop and the 190-helix antigenic sites on the hemagglutinin protein. H3N2v-specific antibodies also neutralized human H3N2 influenza strains naturally circulating between 1995 and 2005. These results reveal a high level of antigenic relatedness between the swine H3N2v virus and previously circulating human strains, consistent with the fact that early human H3 seasonal strains entered the porcine population in the 1990s and reentered the human population, where they had not been circulating, as H3N2v about a decade later. The data also explain the increased susceptibility to H3N2v viruses in young children, who lack prior exposure to human seasonal strains from the 1990s. PMID:27482543

  19. 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

  20. Viral Reassortment and Transmission after Coinfection of Pigs with Classical H1N1 and Triple Reassortant H3N2 Swine Influenza Viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triple reassortant swine influenza viruses circulating in North American pigs contain the internal genes derived from swine (NP, M, NS), human (PB1) and avian (PA and PB2) influenza viruses forming a constellation of genes that is well conserved and called the triple reassortant internal gene (TRIG)...

  1. Triple Reassortant H3N2 Influenza A Viruses, Canada, 2005

    PubMed Central

    Karasin, Alexander I.; Carman, Suzanne; Li, Yan; Bastien, Nathalie; Ojkic, Davor; Alves, David; Charbonneau, George; Henning, Beth M.; Low, Donald E.; Burton, Laura; Broukhanski, George

    2006-01-01

    Since January 2005, H3N2 influenza viruses have been isolated from pigs and turkeys throughout Canada and from a swine farmer and pigs on the same farm in Ontario. These are human/classical swine/avian reassortants similar to viruses that emerged in US pigs in 1998 but with a distinct human-lineage neuraminidase gene. PMID:16836834

  2. 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. PMID:23135159

  3. 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.

  4. Vaccination-challenge studies with a Port Chalmers/73 (H3N2)-based swine influenza virus vaccine: Reflections on vaccine strain updates and on the vaccine potency test.

    PubMed

    De Vleeschauwer, Annebel; Qiu, Yu; Van Reeth, Kristien

    2015-05-11

    The human A/Port Chalmers/1/73 (H3N2) influenza virus strain, the supposed ancestor of European H3N2 swine influenza viruses (SIVs), was used in most commercial SIV vaccines in Europe until recently. If manufacturers want to update vaccine strains, they have to perform laborious intratracheal (IT) challenge experiments and demonstrate reduced virus titres in the lungs of vaccinated pigs. We aimed to examine (a) the ability of a Port Chalmers/73-based commercial vaccine to induce cross-protection against a contemporary European H3N2 SIV and serologic cross-reaction against H3N2 SIVs from Europe and North America and (b) the validity of intranasal (IN) challenge and virus titrations of nasal swabs as alternatives for IT challenge and titrations of lung tissue in vaccine potency tests. Pigs were vaccinated with Suvaxyn Flu(®) and challenged by the IT or IN route with sw/Gent/172/08. Post-vaccination sera were examined in haemagglutination-inhibition assays against vaccine and challenge strains and additional H3N2 SIVs from Europe and North America, including an H3N2 variant virus. Tissues of the respiratory tract and nasal swabs were collected 3 days post challenge (DPCh) and from 0-7 DPCh, respectively, and examined by virus titration. Two vaccinations consistently induced cross-reactive antibodies against European H3N2 SIVs from 1998-2012, but minimal or undetectable antibody titres against North American viruses. Challenge virus titres in the lungs, trachea and nasal mucosa of the vaccinated pigs were significantly reduced after both IT and IN challenge. Yet the reduction of virus titres and nasal shedding was greater after IT challenge. The Port Chalmers/73-based vaccine still offered protection against a European H3N2 SIV isolated 35 years later and with only 86.9% amino acid homology in its HA1, but it is unlikely to protect against H3N2 SIVs that are endemic in North America. We use our data to reflect on vaccine strain updates and on the vaccine potency test.

  5. Experimental infection of European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus) with pandemic 2009 H1N1 and swine H1N1 and H3N2 triple reassortant influenza viruses.

    PubMed

    Nemeth, Nicole M; Oesterle, Paul T; Poulson, Rebecca L; Jones, Cheryl A; Tompkins, S Mark; Brown, Justin D; Stallknecht, David E

    2013-04-01

    European Starlings (Sturnus vulgaris) and House Sparrows (Passer domesticus) are common peridomestic passerine birds that are often associated with domestic animal production facilities. This association provides a potential means for pathogen transmission between facilities. We inoculated European Starlings and House Sparrows with three non-avian influenza virus strains: two swine isolates (H1N1 and H3N2) and one human isolate representing the H1N1 pandemic strain that originated from swine. No viral shedding was observed in House Sparrows, and shedding was minimal and transient in two of 12 (17%) European Starlings. One of these two infected Starlings seroconverted 14 days after inoculation. These results suggest that these two passerine species are minimally susceptible to current influenza viruses in domestic pigs and therefore pose a negligible risk for transmission between or within swine production facilities. PMID:23568924

  6. 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

  7. Impact of prior seasonal H3N2 influenza vaccination or infection on protection and transmission of emerging variants of influenza A(H3N2)v virus in ferrets.

    PubMed

    Houser, Katherine V; Pearce, Melissa B; Katz, Jacqueline M; Tumpey, Terrence M

    2013-12-01

    Influenza H3N2 A viruses continue to circulate in swine and occasionally infect humans, resulting in outbreaks of variant influenza H3N2 [A(H3N2)v] virus. It has been previously demonstrated in ferrets that A(H3N2)v viruses transmit as efficiently as seasonal influenza viruses, raising concern over the pandemic potential of these viruses. However, A(H3N2)v viruses have not acquired the ability to transmit efficiently among humans, which may be due in part to existing cross-reactive immunity to A(H3N2)v viruses. Although current seasonal H3N2 and A(H3N2)v viruses are antigenically distinct from one another, historical H3N2 viruses have some antigenic similarity to A(H3N2)v viruses and previous exposure to these viruses may provide a measure of immune protection sufficient to dampen A(H3N2)v virus transmission. Here, we evaluated whether prior seasonal H3N2 influenza virus vaccination or infection affects virus replication and transmission of A(H3N2)v virus in the ferret animal model. We found that the seasonal trivalent inactivated influenza virus vaccine (TIV) or a monovalent vaccine prepared from an antigenically related 1992 seasonal influenza H3N2 (A/Beijing/32/1992) virus failed to substantially reduce A(H3N2)v (A/Indiana/08/2011) virus shedding and subsequent transmission to naive hosts. Conversely, ferrets primed by seasonal H3N2 virus infection displayed reduced A(H3N2)v virus shedding following challenge, which blunted transmission to naive ferrets. A higher level of specific IgG and IgA antibody titers detected among infected versus vaccinated ferrets was associated with the degree of protection offered by seasonal H3N2 virus infection. The data demonstrate in ferrets that the efficiency of A(H3N2)v transmission is disrupted by preexisting immunity induced by seasonal H3N2 virus infection.

  8. Divergent immune responses and disease outcomes in piglets immunized with inactivated and attenuated H3N2 swine influenza vaccines in the presence of maternally-derived antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine-associated enhanced respiratory disease (VAERD) can occur in pigs immunized with whole-inactivated influenza virus (WIV) vaccine and subsequently infected with an antigenically divergent virus of the same HA subtype. Live-attenuated influenza virus (LAIV) vaccines administered intranasally h...

  9. 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

  10. Increased diversity of H3N2 influenza virus in pigs in the United States and implications for pigs and humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2011-2012 at least 320 human cases of H3N2 (H3N2v) viruses closely related to swine influenza A viruses (IAV) were detected in the United States. We performed phylogenetic analysis of 200 whole genome sequences of North American swine IAV to identify reassortment events and compare these novel ge...

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

    PubMed

    Epperson, Scott; Jhung, Michael; Richards, Shawn; Quinlisk, Patricia; Ball, Lauren; Moll, Mària; Boulton, Rachelle; Haddy, Loretta; Biggerstaff, Matthew; Brammer, Lynnette; Trock, Susan; Burns, Erin; Gomez, Thomas; Wong, Karen K; Katz, Jackie; Lindstrom, Stephen; Klimov, Alexander; Bresee, Joseph S; Jernigan, Daniel B; Cox, Nancy; Finelli, Lyn

    2013-07-01

    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(H1N1)pdm09 pandemic influenza virus. METHODS. A case was defined as a person with laboratory-confirmed H3N2v virus infection. Cases and contacts were interviewed to determine exposure to swine and other animals and to assess potential person-to-person transmission. RESULTS. Median age of cases was 4 years, and 12 of 13 (92%) were children. Pig exposure was identified in 7 (54%) cases. Six of 7 cases with swine exposure (86%) touched pigs, and 1 (14%) was close to pigs without known direct contact. Six cases had no swine exposure, including 2 clusters of suspected person-to-person transmission. All cases had fever; 12 (92%) had respiratory symptoms, and 3 (23%) were hospitalized for influenza. All 13 cases recovered. CONCLUSIONS. H3N2v virus infections were identified at a high rate from August 2011 to April 2012, and cases without swine exposure were identified in influenza-like illness outbreaks, indicating that limited person-to-person transmission likely occurred. Variant influenza viruses rarely result in sustained person-to-person transmission; however, the potential for this H3N2v virus to transmit efficiently is of concern. With minimal preexisting immunity in children and the limited cross-protective effect from seasonal influenza vaccine, the majority of children are susceptible to infection with this novel influenza virus.

  12. Environmental Conditions Affect Exhalation of H3N2 Seasonal and Variant Influenza Viruses and Respiratory Droplet Transmission in Ferrets

    PubMed Central

    Gustin, Kortney M.; Belser, Jessica A.; Veguilla, Vic; Zeng, Hui; Katz, Jacqueline M.; Tumpey, Terrence M.; Maines, Taronna R.

    2015-01-01

    The seasonality of influenza virus infections in temperate climates and the role of environmental conditions like temperature and humidity in the transmission of influenza virus through the air are not well understood. Using ferrets housed at four different environmental conditions, we evaluated the respiratory droplet transmission of two influenza viruses (a seasonal H3N2 virus and an H3N2 variant virus, the etiologic virus of a swine to human summertime infection) and concurrently characterized the aerosol shedding profiles of infected animals. Comparisons were made among the different temperature and humidity conditions and between the two viruses to determine if the H3N2 variant virus exhibited enhanced capabilities that may have contributed to the infections occurring in the summer. We report here that although increased levels of H3N2 variant virus were found in ferret nasal wash and exhaled aerosol samples compared to the seasonal H3N2 virus, enhanced respiratory droplet transmission was not observed under any of the environmental settings. However, overall environmental conditions were shown to modulate the frequency of influenza virus transmission through the air. Transmission occurred most frequently at 23°C/30%RH, while the levels of infectious virus in aerosols exhaled by infected ferrets agree with these results. Improving our understanding of how environmental conditions affect influenza virus infectivity and transmission may reveal ways to better protect the public against influenza virus infections. PMID:25969995

  13. Exertional rhabdomyolysis after influenza A (H3N2) infection in a basketball player boy.

    PubMed

    Sevketoglu, E; Kural, B; Beskardes, A E; Hatipoglu, S

    2011-01-01

    A 14-year-old professional basketball player developed symptoms of influenza which was subsequently confirmed to be caused by influenza A (H3N2). He was given a 5-day course of oseltamivir. Two days after completing the course, he resumed basketball and developed rhabdomyolysis associated with acute renal failure and disseminated intravascular coagulation. This appears to be the first report of exercise-induced rhabdomyolysis associated with influenza A (H3N2).

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Isolation of the pandemic (H1N1) 2009 virus and its reassortant with an H3N2 swine influenza virus from healthy weaning pigs in Thailand in 2011.

    PubMed

    Hiromoto, Yasuaki; Parchariyanon, Sujira; Ketusing, Naree; Netrabukkana, Punnaporn; Hayashi, Tsuyoshi; Kobayashi, Tomoko; Takemae, Nobuhiro; Saito, Takehiko

    2012-10-01

    A total of 300 nasal swabs were collected from 5 pig farms in two provinces in the Eastern part of Thailand in February 2011 and were subjected to viral isolation of influenza A viruses. Two H3N2 and 6 H1N1 influenza A viruses were isolated from swabs collected from clinically healthy weaning pigs on farms in Chonburi and Chachoengsao provinces, respectively. The H3N2 isolates consisted of the hemagglutinin (HA) and neuraminidase (NA) genes closely related to Thai SIVs and derived from a cluster of human seasonal H3N2 strains circulating around 1996-1997. The remaining gene segments of the isolates originated from the Pandemic (H1N1) 2009 (A (H1N1) pdm09) virus. Antigenicity of the H3N2 isolates was distinguishable from a human seasonal vaccine strain in the 1996-1998 seasons that represented antigenicity of the seasonal strains around 1996-1998. Nasal swabs from a Chachoengsao farm yielded A (H1N1) pdm09 viruses in chicken embryonated eggs and MDCK cells. A (H1N1) pdm09 viruses isolated in this study grew poorly in MDCK cells. Deduced amino acid sequences of the HA1 region of the HA protein of egg isolated viruses were identical to the sequences directly amplified from original swab samples. Our result demonstrated that the A (H1N1) pdm09 virus has been established in the Thai pig population and this has resulted in genetic reassortment with Thai SIV that previously circulated among pigs.

  16. Outbreak of influenza A (H3N2) variant virus infection among attendees of an agricultural fair, Pennsylvania, USA, 2011.

    PubMed

    Wong, Karen K; 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

    2012-12-01

    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.

  17. Phylodynamics of influenza A(H3N2) in South America, 1999-2012.

    PubMed

    Born, Priscila Silva; Siqueira, Marilda Mendonça; Faria, Nuno Rodrigues; Resende, Paola Cristina; Motta, Fernando Couto; Bello, Gonzalo

    2016-09-01

    The limited influenza A(H3N2) genetic data available from the Southern Hemisphere (particularly from Africa and Latin America), constrains the accurate reconstruction of viral dissemination dynamics within those regions. Our objective was to describe the spatial dissemination dynamics of influenza A(H3N2) within South America. A total of 469 sequences of the HA1 portion of the hemagglutinin gene (HA) from influenza A(H3N2) viruses sampled in temperate and tropical South American countries between 1999 and 2012 were combined with available contemporary sequences from Australia, Hong Kong, United Kingdom and the United States. Phylogenetic analyses revealed that influenza A(H3N2) sequences from South America were highly intermixed with sequences from other geographical regions, although a clear geographic virus population structure was detected globally. We identified 14 clades mostly (≥80%) composed of influenza sequences from South American countries. Bayesian phylogeographic analyses of those clades support a significant role of both temperate and tropical regions in the introduction and dissemination of new influenza A(H3N2) strains within South America and identify an intensive bidirectional viral exchange between different geographical areas. These findings indicate that seasonal influenza A(H3N2) epidemics in South America are seeded by both the continuous importation of viral variants from other geographic regions and the short-term persistence of local lineages. This study also supports a complex metapopulation model of influenza A(H3N2) dissemination in South America, with no preferential direction in viral movement between temperate and tropical regions. PMID:27275847

  18. Temporally structured metapopulation dynamics and persistence of influenza A H3N2 virus in humans

    PubMed Central

    Bahl, Justin; Nelson, Martha I.; Chan, Kwok H.; Chen, Rubing; Vijaykrishna, Dhanasekaran; Halpin, Rebecca A.; Stockwell, Timothy B.; Lin, Xudong; Wentworth, David E.; Ghedin, Elodie; Guan, Yi; Peiris, J. S. Malik; Riley, Steven; Rambaut, Andrew; Holmes, Edward C.; Smith, Gavin J. D.

    2011-01-01

    Populations of seasonal influenza virus experience strong annual bottlenecks that pose a considerable extinction risk. It has been suggested that an influenza source population located in tropical Southeast or East Asia seeds annual temperate epidemics. Here we investigate the seasonal dynamics and migration patterns of influenza A H3N2 virus by analysis of virus samples obtained from 2003 to 2006 from Australia, Europe, Japan, New York, New Zealand, Southeast Asia, and newly sequenced viruses from Hong Kong. In contrast to annual temperate epidemics, relatively low levels of relative genetic diversity and no seasonal fluctuations characterized virus populations in tropical Southeast Asia and Hong Kong. Bayesian phylogeographic analysis using discrete temporal and spatial characters reveal high rates of viral migration between urban centers tested. Although the virus population that migrated between Southeast Asia and Hong Kong persisted through time, this was dependent on virus input from temperate regions and these tropical regions did not maintain a source for annual H3N2 influenza epidemics. We further show that multiple lineages may seed annual influenza epidemics, and that each region may function as a potential source population. We therefore propose that the global persistence of H3N2 influenza A virus is the result of a migrating metapopulation in which multiple different localities may seed seasonal epidemics in temperate regions in a given year. Such complex global migration dynamics may confound control efforts and contribute to the emergence and spread of antigenic variants and drug-resistant viruses. PMID:22084096

  19. A novel canine influenza H3N2 virus isolated from cats in an animal shelter.

    PubMed

    Jeoung, Hye-Young; Lim, Seong-In; Shin, Bo-Hye; Lim, Ji-Ae; Song, Jae-Young; Song, Dae-Sub; Kang, Bo-Kyu; Moon, Hyoung-Joon; An, Dong-Jun

    2013-08-30

    The interspecies transmission of avian-origin H3N2 canine influenza virus (CIV) to dogs was first reported in 2007. The present study characterized a novel CIV H3N2 isolated from cats in an animal shelter. A comparative analysis of the deduced amino acid sequences of the A/Canine/Korea/CY009/2010(H3N2) (CY009) and A/Feline/Korea/FY028/2010 (H3N2) (FY028) strains isolated from dogs and cats, respectively, in the animal shelter identified point mutations in 18 amino acid positions within eight viral genes. Interestingly, CY009 and FY028 replicated well in specific pathogen-free embryonated chicken eggs and in mice, respectively. Mice infected with the FY028 strain exhibited significant over expression of IL-10, TNF-α, and IFN-γ (p<0.001) at 3 days postinfection. Thus, an emergency monitoring system should be developed to identify influenza mutations that occur during interspecies transmission in companion animals and for continuous public health surveillance.

  20. Detection of H3N2 canine influenza virus using a Quartz Crystal Microbalance.

    PubMed

    Kim, Yong Kwan; Lim, Seong-In; Cho, Yoon-Young; Choi, Sarah; Song, Jae-Young; An, Dong-Jun

    2014-11-01

    Label-free technology-based Quartz Crystal Microbalance (QCM) is an emerging tool in biological research. In this study, QCM was applied successfully for the rapid diagnosis of H3N2 canine influenza virus (CIV) infection. ProLinker™ B, a calixcrown derivative, enables antibodies to be attached to a gold-coated quartz surface and positioned in a regular pattern with the correct orientation. The ProLinker-coated quartz-based assay detected H3N2 CIV at lower concentrations (2(2) HA unit) than a commercial immunochromatography Ag kit (2(3) HA unit). Three independent experiments in which H3N2 CIV-positive reference samples were applied to an anti-CIV nucleoprotein (NP) monoclonal antibody immobilized on a quartz surface yielded standard deviations (SD) of ≤5%, indicating high reproducibility. In addition, the QCM assay with a cut-off value (-140 Hz) showed 97.1% (34/35) sensitivity and 94.7% (36/38) specificity in testing 73 field saliva samples, respectively. Thus, the QCM assay described herein will be a valuable tool for the rapid diagnosis of H3N2 CIV infection with high sensitivity and specificity, and should overcome several of the disadvantages and limitations inherent in the commercial immunochromatography Ag kit. PMID:25072379

  1. 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.

  2. 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

  3. Explaining the geographical origins of seasonal influenza A (H3N2)

    PubMed Central

    Bedford, Trevor; Cobey, Sarah

    2016-01-01

    Most antigenically novel and evolutionarily successful strains of seasonal influenza A (H3N2) originate in East, South and Southeast Asia. To understand this pattern, we simulated the ecological and evolutionary dynamics of influenza in a host metapopulation representing the temperate north, tropics and temperate south. Although seasonality and air traffic are frequently used to explain global migratory patterns of influenza, we find that other factors may have a comparable or greater impact. Notably, a region's basic reproductive number (R0) strongly affects the antigenic evolution of its viral population and the probability that its strains will spread and fix globally: a 17–28% higher R0 in one region can explain the observed patterns. Seasonality, in contrast, increases the probability that a tropical (less seasonal) population will export evolutionarily successful strains but alone does not predict that these strains will be antigenically advanced. The relative sizes of different host populations, their birth and death rates, and the region in which H3N2 first appears affect influenza's phylogeography in different but relatively minor ways. These results suggest general principles that dictate the spatial dynamics of antigenically evolving pathogens and offer predictions for how changes in human ecology might affect influenza evolution. PMID:27629034

  4. Explaining the geographical origins of seasonal influenza A (H3N2).

    PubMed

    Wen, Frank; Bedford, Trevor; Cobey, Sarah

    2016-09-14

    Most antigenically novel and evolutionarily successful strains of seasonal influenza A (H3N2) originate in East, South and Southeast Asia. To understand this pattern, we simulated the ecological and evolutionary dynamics of influenza in a host metapopulation representing the temperate north, tropics and temperate south. Although seasonality and air traffic are frequently used to explain global migratory patterns of influenza, we find that other factors may have a comparable or greater impact. Notably, a region's basic reproductive number (R0) strongly affects the antigenic evolution of its viral population and the probability that its strains will spread and fix globally: a 17-28% higher R0 in one region can explain the observed patterns. Seasonality, in contrast, increases the probability that a tropical (less seasonal) population will export evolutionarily successful strains but alone does not predict that these strains will be antigenically advanced. The relative sizes of different host populations, their birth and death rates, and the region in which H3N2 first appears affect influenza's phylogeography in different but relatively minor ways. These results suggest general principles that dictate the spatial dynamics of antigenically evolving pathogens and offer predictions for how changes in human ecology might affect influenza evolution. PMID:27629034

  5. Selecting vaccine strains for H3N2 human influenza A virus.

    PubMed

    Suzuki, Yoshiyuki

    2015-06-01

    H3N2 human influenza A virus causes epidemics of influenza mainly in the winter season in temperate regions. Since the antigenicity of this virus evolves rapidly, several attempts have been made to predict the major amino acid sequence of hemagglutinin 1 (HA1) in the target season of vaccination. However, the usefulness of predicted sequence was unclear because its relationship to the antigenicity was unknown. Here the antigenic model for estimating the degree of antigenic difference (antigenic distance) between amino acid sequences of HA1 was integrated into the process of selecting vaccine strains for H3N2 human influenza A virus. When the effectiveness of a potential vaccine strain for a target season was evaluated retrospectively using the average antigenic distance between the strain and the epidemic viruses sampled in the target season, the most effective vaccine strain was identified mostly in the season one year before the target season (pre-target season). Effectiveness of actual vaccines appeared to be lower than that of the strains randomly chosen in the pre-target season on average. It was recommended to replace the vaccine strain for every target season with the strain having the smallest average antigenic distance to the others in the pre-target season. The procedure of selecting vaccine strains for future epidemic seasons described in the present study was implemented in the influenza virus forecasting system (INFLUCAST) (http://www.nsc.nagoya-cu.ac.jp/~yossuzuk/influcast.html).

  6. Characterization of a novel H3N2 influenza virus isolated from domestic ducks in China.

    PubMed

    Li, Chong; Yu, Meng; Liu, Litao; Sun, Honglei

    2016-08-01

    Cases of human infection with a novel H7N9 avian influenza virus (AIV) were first reported in March 2013, which caused 115 deaths within a single year. Beyond that, other subtypes of H7 AIV were isolated from poultry in eastern China during the same period, including H7N7 and H7N2 AIV. In the present study, a subtype H3N2 AIV was isolated from ducks from Anhui Province, China. Sequence and phylogenetic analyses revealed that seven gene segments of this virus showed the highest sequence homology with that of the H7 subtype influenza virus, which is presumed to be the reassortants of the H3 and H7 subtypes AIV. The present study also reconfirmed that the reassortment between the H7 subtype and waterfowl-originating AIVs universally occurred in waterfowl. Animal inoculation tests showed that the virus has low pathogenicity in chickens; however, it could be replicated in the lungs of mice. The emergence of this H3N2 isolate emphasizes the importance of enhancing the surveillance of waterfowl-originating AIVs, the identification of novel reassortant strains, and characterization of their biological properties.

  7. Cellular and Humoral Cross-Immunity against Two H3N2v Influenza Strains in Presumably Unexposed Healthy and HIV-Infected Subjects

    PubMed Central

    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. PMID:25162670

  8. Origins and Evolutionary Dynamics of H3N2 Canine Influenza Virus

    PubMed Central

    Zhu, Henan; Hughes, Joseph

    2015-01-01

    ABSTRACT 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. IMPORTANCE 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

  9. 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.

  10. The origin and global emergence of adamantane resistant A/H3N2 influenza viruses

    PubMed Central

    Nelson, Martha I.; Simonsen, Lone; Viboud, Cécile; Miller, Mark A.; Holmes, Edward C.

    2009-01-01

    Resistance to the adamantane class of antiviral drugs by human A/H3N2 influenza viruses currently exceeds 90% in the United States and multiple Asian countries. Adamantane resistance is associated with a single amino acid change (S31N) in the M2 protein, which was shown to rapidly disseminate globally in 2005 in association with a genome reassortment event. However, the exact origin of influenza A/H3N2 viruses carrying the S31N mutation has not been characterized, particularly in South-East Asia. We therefore conducted a phylogenetic analysis of the HA, NA, and M1/2 segments of viral isolates collected between 1997-2007 from temperate localities in the Northern hemisphere (New York State, United States, 492 isolates) and Southern hemisphere (New Zealand and Australia, 629 isolates) and a subtropical locality in South-East Asia (Hong Kong, 281 isolates). We find that although the S31N mutation was independently introduced at least 11 times, the vast majority of resistant viruses now circulating globally descend from a single introduction that was first detected in the summer of 2003 in Hong Kong. These resistant viruses were continually detected in Hong Kong throughout 2003-2005, acquired a novel HA through reassortment during the first part of 2005, and thereafter spread globally. The emergence and persistence of adamantane-resistant viruses in Hong Kong further supports a source-sink model of global influenza virus ecology, in which South-East Asia experiences continuous viral activity and repeatedly seeds epidemics in temperate areas. PMID:19394063

  11. 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

  12. Cooperation between distinct viral variants promotes growth of H3N2 influenza in cell culture.

    PubMed

    Xue, Katherine S; Hooper, Kathryn A; Ollodart, Anja R; Dingens, Adam S; Bloom, Jesse D

    2016-01-01

    RNA viruses rapidly diversify into quasispecies of related genotypes. This genetic diversity has long been known to facilitate adaptation, but recent studies have suggested that cooperation between variants might also increase population fitness. Here, we demonstrate strong cooperation between two H3N2 influenza variants that differ by a single mutation at residue 151 in neuraminidase, which normally mediates viral exit from host cells. Residue 151 is often annotated as an ambiguous amino acid in sequenced isolates, indicating mixed viral populations. We show that mixed populations grow better than either variant alone in cell culture. Pure populations of either variant generate the other through mutation and then stably maintain a mix of the two genotypes. We suggest that cooperation arises because mixed populations combine one variant's proficiency at cell entry with the other's proficiency at cell exit. Our work demonstrates a specific cooperative interaction between defined variants in a viral quasispecies. PMID:26978794

  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. Reconstruction of H3N2 influenza virus based virosome in-vitro

    PubMed Central

    Abdoli, Asghar; Soleimanjahi, Hoorieh; Kheiri, Masoumeh Tavassoti; Jamali, Abbas; Sohani, Hesam; Abdoli, Mohsen; Rahmatollahi, Hamid Reza

    2013-01-01

    Background and Objectives Virosomes are Virus Like Particles (VLP) assembled in-vitro. Influenza virosomes maintain the cell binding and membrane fusion activity of the wild type virus but are devoid of viral genetic material or internal proteins. Influenza virosomes mimic the natural antigen presentation route of the influenza virus. Methods Virosomes were prepared by membrane solubilization and reconstitution. Briefly, the Madine-Darby Canine kidney (MDCK) cell line was cultivated on microcarrier beads inoculated with influenza virus strain A/X-47 (H3N2). The culture medium was harvested and clarified. Subsequently, virus was concentrated and purified by ultrafiltration and ultracentrifugation. The purified viral membrane was dissolved by adding 375 µl of 200 mM 1, 2-dicaproyl-sn-glycero-3-phosphocholine (DCPC) in HEPES-buffered saline (HBS). Nucleocapsid was removed by ultracentrifugation. The supernatant consisting of phospholipids and glycoproteins of the influenza virus was reconstituted by removal of DCPC using overnight dialysis against Hank's Buffered Saline (HBS) solution at 4°C. After dialysis, crude virosome preparation was layered over a discontinuous sucrose gradient in order to separate non-incorporated material from the reconstituted virus membranes. Results The virosome harvested from the boundary of the two sucrose layers successfully was identified by the Hemagglutination assay and western blotting. Conclusion Use of a dialyzable short-chain phospholipid (DCPC) is an efficient procedure for solubilization and reconstitution of influenza virus virosomes and has not caused structural changes in a major envelope glycoprotein (hemagglutinin protein) on the surface of virosome. PMID:23825736

  15. Myopericarditis and exertional rhabdomyolysis following an influenza A (H3N2) infection

    PubMed Central

    2013-01-01

    Background Acute myopericarditis and exertional rhabdomyolysis, two uncommon but well-described diseases with potentially life-threatening effects, are generally considered as independent clinical entities. However, they may in fact be pathophysiologically related under certain circumstances. This is the first ever report of influenza myopericarditis provoked by exertional rhabdomyolysis to the best of our knowledge. Case presentation A 25-year-old immunocompetent Chinese man presented with bilateral leg pain, dizziness, and shortness of breath on admission soon after completing vigorous training comprising running drills. Exertional rhabdomyolysis was diagnosed with 44 fold high serum creatine phosphokinase. Then he developed chest pain, pericardial effusion, changes of electrocardiography and positive troponin I suggestive of myopericarditis. Influenza A (H3N2) virus infection was confirmed by polymerase chain reaction analysis of nasopharyngeal wash samples. Other possible infective and autoimmune causes were excluded. Patient recovered completely with anti-inflammatory therapy and the supportive care. Conclusion This case suggests that clinicians who treat patients with exertional rhabdomyolysis should be aware of the potential vulnerability to acute myopericarditis, especially in the presence of recent influenza A infection. PMID:23786640

  16. Virulence of a novel reassortant canine H3N2 influenza virus in ferret, dog and mouse models.

    PubMed

    Lyoo, Kwang-Soo; Na, Woonsung; Yeom, Minjoo; Jeong, Dae-Gwin; Kim, Chang-Ung; Kim, Jeong-Ki; Song, Daesub

    2016-07-01

    An outbreak of a canine influenza virus (CIV) H3N2 reassortant derived from pandemic (pdm) H1N1 and CIV H3N2 in companion animals has underscored the urgent need to monitor CIV infections for potential zoonotic transmission of influenza viruses to humans. In this study, we assessed the virulence of a novel CIV H3N2 reassortant, VC378, which was obtained from a dog that was coinfected with pdm H1N1 and CIV H3N2, in ferrets, dogs, and mice. Significantly enhanced virulence of VC378 was demonstrated in mice, although the transmissibility and pathogenicity of VC378 were similar to those of classical H3N2 in ferrets and dogs. This is notable because mice inoculated with an equivalent dose of classical CIV H3N2 showed no clinical signs and no lethality. We found that the PA and NS gene segments of VC378 were introduced from pdmH1N1, and these genes included the amino acid substitutions PA-P224S and NS-I123V, which were previously found to be associated with increased virulence in mice. Thus, we speculate that the natural reassortment between pdm H1N1 and CIV H3N2 can confer virulence and that continuous surveillance is needed to monitor the evolution of CIV in companion animals. PMID:27138550

  17. Glycosylation changes in the globular head of H3N2 influenza hemagglutinin modulate receptor binding without affecting virus virulence

    PubMed Central

    Alymova, Irina V.; York, Ian A.; Air, Gillian M.; Cipollo, John F.; Gulati, Shelly; Baranovich, Tatiana; Kumar, Amrita; Zeng, Hui; Gansebom, Shane; McCullers, Jonathan A.

    2016-01-01

    Since the emergence of human H3N2 influenza A viruses in the pandemic of 1968, these viruses have become established as strains of moderate severity. A decline in virulence has been accompanied by glycan accumulation on the hemagglutinin globular head, and hemagglutinin receptor binding has changed from recognition of a broad spectrum of glycan receptors to a narrower spectrum. The relationship between increased glycosylation, binding changes, and reduction in H3N2 virulence is not clear. We evaluated the effect of hemagglutinin glycosylation on receptor binding and virulence of engineered H3N2 viruses. We demonstrate that low-binding virus is as virulent as higher binding counterparts, suggesting that H3N2 infection does not require either recognition of a wide variety of, or high avidity binding to, receptors. Among the few glycans recognized with low-binding virus, there were two structures that were bound by the vast majority of H3N2 viruses isolated between 1968 and 2012. We suggest that these two structures support physiologically relevant binding of H3N2 hemagglutinin and that this physiologically relevant binding has not changed since the 1968 pandemic. Therefore binding changes did not contribute to reduced severity of seasonal H3N2 viruses. This work will help direct the search for factors enhancing influenza virulence. PMID:27796371

  18. [Successful Treatment of Seasonal Influenza A (H3N2) infection-related Hemophagocytic Lymphocytosis in an Elderly Man].

    PubMed

    Suzuki, Shintaro; Tanaka, Akihiko; Fukuda, Yosuke; Miyata, Yoshito; Murata, Yasunori; Kishino-Oki, Yasunari; Homma, Tetsuya; Ohnishi, Tsukasa; Sagara, Hironori

    2016-01-01

    A 79-year-old man experienced severe chronic obstructive pulmonary disease (COPD) and was receiving treatment for ischemic heart disease. Starting from dizziness and chilliness, he lost consciousness after few days. He was taken to our emergency department. On initial evaluation, he complained of dyspnea and was afebrile with a pulse rate, blood pressure, and respiratory rate of 105 beats/min, 112/98mmHg, and 28 breath/min, respectively. His respiratory sounds were clear and chest radiography did not show any abnormal shadows, but his arterial blood gas examination showed type II respiratory failure. Because the nasopharyngeal seasonal influenza A virus (IAV) test was positive, the patient was admitted with the diagnosis of acute exacerbation of COPD due to IAV. We administered peramivir, a specific anti-influenza drug, and started mechanical ventilation. Over time, he started to show signs of disseminated intravascular coagulation, such as multiple organ failure and thrombocytopenia. Subsequently, blood tests showed elevation of ferritin and soluble interleukin 2 receptor (sIL2R); microscopic examination of the peripheral blood revealed hemophagocytosis. Secondary hemophagocytic lymphohistiocytosis (HLH) due to IAV was diagnosed and together with corticosteroid therapy, intravenous gamma globulin was administered from the 3rd clinical day. The patint was saved with our early diagnosis and treatment of HLH and was discharged on the 92nd clinical day. Viral-induced HLH, formerly known as virus-associated hemophagocytic syndrome (VAHS), leads to multiple organ failure due to a cytokine storm scattered by viral-infected pathogenic inflammatory cells. It is well known that pandemic swine flu causes secondary HLH leading to poor outcomes. Currently, not much is known about HLH due to seasonal flu; particularly, IAV (H3N2)-related HLH cases are rare and reported cases showed poor outcomes as well. With an early diagnosis and minimum immunotherapy, we report herein on a

  19. Identification of the IFN-β response in H3N2 canine influenza virus infection.

    PubMed

    Su, Shuo; Huang, San; Fu, Cheng; Wang, Lifang; Zheng, Yun; Zhou, Pei; Li, Shoujun

    2016-01-01

    Canine influenza viruses (CIVs) circulate continuously in the dog population, providing opportunities for exposure to humans and other species. Although the dog genome has been sequenced, innate immunity in dogs is not well characterized, which limits the understanding of H3N2 canine influenza virus pathogenesis. Equally, how this virus evades the canine host innate immune response to successfully establish infection remains unclear. To analyse the IFN-β response to CIV infection in Madin-Darby canine kidney cells, the canine IFN-β promoter sequence and its positive regulatory domain motifs were first cloned and identified using a luciferase reporter system. Next, we found that infection with the CIV strain GD/12 blocked the IFN-β response primarily by inhibiting the NF-κB and IFN regulatory factor 3 (IRF3) signalling pathways. Expression of GD/12 non-structural protein 1 alone was sufficient to inhibit Sendai virus-induced NF-κB and IRF3 activation by suppressing p65 and IRF3 phosphorylation, suggesting the important role of this protein in the CIV-mediated inhibition of the IFN-β response. These results suggest that inhibition of the IFN-β signalling pathway may have played a role in CIV establishment and spread in dog populations. PMID:26490006

  20. Identification of the IFN-β response in H3N2 canine influenza virus infection.

    PubMed

    Su, Shuo; Huang, San; Fu, Cheng; Wang, Lifang; Zheng, Yun; Zhou, Pei; Li, Shoujun

    2016-01-01

    Canine influenza viruses (CIVs) circulate continuously in the dog population, providing opportunities for exposure to humans and other species. Although the dog genome has been sequenced, innate immunity in dogs is not well characterized, which limits the understanding of H3N2 canine influenza virus pathogenesis. Equally, how this virus evades the canine host innate immune response to successfully establish infection remains unclear. To analyse the IFN-β response to CIV infection in Madin-Darby canine kidney cells, the canine IFN-β promoter sequence and its positive regulatory domain motifs were first cloned and identified using a luciferase reporter system. Next, we found that infection with the CIV strain GD/12 blocked the IFN-β response primarily by inhibiting the NF-κB and IFN regulatory factor 3 (IRF3) signalling pathways. Expression of GD/12 non-structural protein 1 alone was sufficient to inhibit Sendai virus-induced NF-κB and IRF3 activation by suppressing p65 and IRF3 phosphorylation, suggesting the important role of this protein in the CIV-mediated inhibition of the IFN-β response. These results suggest that inhibition of the IFN-β signalling pathway may have played a role in CIV establishment and spread in dog populations.

  1. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Analysis of the beta-propiolactone sensitivity and optimization of inactivation methods for human influenza H3N2 virus.

    PubMed

    Sasaki, Yutaka; Yoshino, Naoto; Sato, Shigehiro; Muraki, Yasushi

    2016-09-01

    Beta-propiolactone (BPL) is used as an inactivating reagent for influenza virus in a number of countries. However, the treatment of viruses with BPL occasionally results in a decrease in the hemagglutinin (HA) titer, which complicates vaccine development. In the present study, we examined the biological and biochemical characteristics of human H1N1 and H3N2 viruses treated with BPL, and developed an inactivation method for BPL-sensitive viruses. A significant decrease in HA titer was detected in the H3N2 viruses examined. The decrease in the pH of the virus fluid was not associated with the decreased HA titer, indicating that the decrease in HA titer for the H3N2 virus is the result of the direct effect of BPL. Excessive modification of M1 by BPL and loss of virion diameter were observed in 0.1% BPL-treated H3N2 virus. Taken together, these results suggest that the BPL sensitivity of H3N2 virus results from disruption of the virion. By contrast, the H3N2 virus was successfully inactivated by 0.02% BPL without a significant decrease in the HA titer or disruption of virion structure. Furthermore, we found that the 0.02% BPL in the virion preparation was hydrolyzed successfully by incubation at 37°C for 7h. Thus, mild treatment with a low concentration of BPL enabled us to inactivate the H3N2 virus.

  4. Prevalence and risk factors for H1N1 and H3N2 influenza A virus infections in Minnesota turkey premises.

    PubMed

    Corzo, Cesar A; Gramer, Marie; Lauer, Dale; Davies, Peter R

    2012-09-01

    Influenza virus infections can cause respiratory and systemic disease of variable severity and also result in economic losses for the turkey industry. Several subtypes of influenza can infect turkeys, causing diverse clinical signs. Influenza subtypes of swine origin have been diagnosed in turkey premises; however, it is not known how common these infections are nor the likely routes of transmission. We conducted a cross-sectional study to estimate the prevalence of influenza viruses and examine factors associated with infection on Minnesota turkey premises. Results from influenza diagnostic tests and turkey and pig premise location data were obtained from the Minnesota Poultry Testing Laboratory and the Minnesota Board of Animal Health, respectively, from January 2007 to September 2008. Diagnostic data from 356 premises were obtained, of which 17 premises tested positive for antibodies to influenza A virus by agar gel immunodiffusion assay and were confirmed as either H1N1 or H3N2 influenza viruses by hemagglutination and neuraminidase inhibition assays. Influenza infection status was associated with proximity to pig premises and flock size. The latter had a sparing effect on influenza status. This study suggests that H1N1 and H3N2 influenza virus infections of turkey premises in Minnesota are an uncommon event. The route of influenza virus transmission could not be determined; however, the findings suggest that airborne transmission should be considered in future studies.

  5. Computational Prediction of Vaccine Strains for Human Influenza A (H3N2) Viruses

    PubMed Central

    Steinbrück, L.; Klingen, T. R.

    2014-01-01

    ABSTRACT Human influenza A viruses are rapidly evolving pathogens that cause substantial morbidity and mortality in seasonal epidemics around the globe. To ensure continued protection, the strains used for the production of the seasonal influenza vaccine have to be regularly updated, which involves data collection and analysis by numerous experts worldwide. Computer-guided analysis is becoming increasingly important in this problem due to the vast amounts of generated data. We here describe a computational method for selecting a suitable strain for production of the human influenza A virus vaccine. It interprets available antigenic and genomic sequence data based on measures of antigenic novelty and rate of propagation of the viral strains throughout the population. For viral isolates sampled between 2002 and 2007, we used this method to predict the antigenic evolution of the H3N2 viruses in retrospective testing scenarios. When seasons were scored as true or false predictions, our method returned six true positives, three false negatives, eight true negatives, and one false positive, or 78% accuracy overall. In comparison to the recommendations by the WHO, we identified the correct antigenic variant once at the same time and twice one season ahead. Even though it cannot be ruled out that practical reasons such as lack of a sufficiently well-growing candidate strain may in some cases have prevented recommendation of the best-matching strain by the WHO, our computational decision procedure allows quantitative interpretation of the growing amounts of data and may help to match the vaccine better to predominating strains in seasonal influenza epidemics. IMPORTANCE Human influenza A viruses continuously change antigenically to circumvent the immune protection evoked by vaccination or previously circulating viral strains. To maintain vaccine protection and thereby reduce the mortality and morbidity caused by infections, regular updates of the vaccine strains are

  6. Computational prediction of vaccine strains for human influenza A (H3N2) viruses.

    PubMed

    Steinbrück, L; Klingen, T R; McHardy, A C

    2014-10-01

    Human influenza A viruses are rapidly evolving pathogens that cause substantial morbidity and mortality in seasonal epidemics around the globe. To ensure continued protection, the strains used for the production of the seasonal influenza vaccine have to be regularly updated, which involves data collection and analysis by numerous experts worldwide. Computer-guided analysis is becoming increasingly important in this problem due to the vast amounts of generated data. We here describe a computational method for selecting a suitable strain for production of the human influenza A virus vaccine. It interprets available antigenic and genomic sequence data based on measures of antigenic novelty and rate of propagation of the viral strains throughout the population. For viral isolates sampled between 2002 and 2007, we used this method to predict the antigenic evolution of the H3N2 viruses in retrospective testing scenarios. When seasons were scored as true or false predictions, our method returned six true positives, three false negatives, eight true negatives, and one false positive, or 78% accuracy overall. In comparison to the recommendations by the WHO, we identified the correct antigenic variant once at the same time and twice one season ahead. Even though it cannot be ruled out that practical reasons such as lack of a sufficiently well-growing candidate strain may in some cases have prevented recommendation of the best-matching strain by the WHO, our computational decision procedure allows quantitative interpretation of the growing amounts of data and may help to match the vaccine better to predominating strains in seasonal influenza epidemics. Importance: Human influenza A viruses continuously change antigenically to circumvent the immune protection evoked by vaccination or previously circulating viral strains. To maintain vaccine protection and thereby reduce the mortality and morbidity caused by infections, regular updates of the vaccine strains are required. We

  7. Identification of Hemagglutinin Residues Responsible for H3N2 Antigenic Drift during the 2014-2015 Influenza Season.

    PubMed

    Chambers, Benjamin S; Parkhouse, Kaela; Ross, Ted M; Alby, Kevin; Hensley, Scott E

    2015-07-01

    Influenza vaccines must be updated regularly because influenza viruses continuously acquire mutations in antibody binding sites of hemagglutinin (HA). The majority of H3N2 strains circulating in the Northern Hemisphere during the 2014-2015 season are antigenically mismatched to the A/Texas/50/2012 H3N2 vaccine strain. Recent H3N2 strains possess several new HA mutations, and it is unknown which of these mutations contribute to the 2014-2015 vaccine mismatch. Here, we use reverse genetics to demonstrate that mutations in HA antigenic site B are primarily responsible for the current mismatch. Sera isolated from vaccinated humans and infected ferrets and sheep had reduced hemagglutination inhibition and in vitro neutralization titers against reverse-genetics-derived viruses possessing mutations in the HA antigenic site B. These data provide an antigenic explanation for the low influenza vaccine efficacy observed during the 2014-2015 influenza season. Furthermore, our data support the World Health Organization's decision to update the H3N2 component of future vaccine formulations.

  8. 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

  9. Restricted Infectivity of a Human-Lineage H3N2 Influenza A Virus in Pigs Is Hemagglutinin and Neuraminidase Gene Dependent

    PubMed Central

    Landolt, Gabriele A.; Karasin, Alexander I.; Schutten, Melissa M.; Olsen, Christopher W.

    2006-01-01

    Influenza A viruses cause pandemics at sporadic intervals. Pandemic viruses can potentially be introduced into the human population through in toto transfer of an avian influenza virus or through reassortment between avian and human strains. Pigs are believed to play a central role in the creation of pandemic viruses through reassortment because of their susceptibility to infection with both avian and human influenza viruses. However, we recently found that a human-lineage H3N2 influenza virus was highly restricted in its ability to infect pigs after intranasal inoculation. We hypothesized that this restricted infectivity phenotype was controlled by the hemagglutinin (HA) and neuraminidase (NA). To test this, we infected pigs with reverse genetics-created HA plus NA reassortant viruses. Specifically, introduction of the HA and NA genes of a contemporary H3N2 swine virus into the genetic background of the wholly human virus resulted in a significant increase in virus shedding and pathogenicity. These data indicate that the HA/NA can play important roles in controlling human influenza virus infectivity in pigs. The results further support the premise that a barrier exists to human influenza virus infection in pigs, which may limit the role of pigs in pandemic virus creation through reassortment of human and avian influenza viruses. PMID:16455873

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

    PubMed Central

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

    2015-01-01

    Background 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. Study design 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. Results 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 104/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. Conclusions It is unclear how often influenza co-infections occur, but laboratories should consider influenza co-infections during routine surveillance activities. PMID:26590689

  11. Antigenic variation of the human influenza A (H3N2) virus during the 2014-2015 winter season.

    PubMed

    Hua, Sha; Li, XiYan; Liu, Mi; Cheng, YanHui; Peng, YouSong; Huang, WeiJuan; Tan, MinJu; Wei, HeJiang; Guo, JunFeng; Wang, DaYan; Wu, AiPing; Shu, YueLong; Jiang, TaiJiao

    2015-09-01

    The human influenza A (H3N2) virus dominated the 2014-2015 winter season in many countries and caused massive morbidity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 (A/Switzerland/9715293/2013-like strains) and HK14 (A/Hong Kong/5738/2014-like strains), co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in mainland China, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an important role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains.

  12. Antigenic variation of the human influenza A (H3N2) virus during the 2014-2015 winter season.

    PubMed

    Hua, Sha; Li, XiYan; Liu, Mi; Cheng, YanHui; Peng, YouSong; Huang, WeiJuan; Tan, MinJu; Wei, HeJiang; Guo, JunFeng; Wang, DaYan; Wu, AiPing; Shu, YueLong; Jiang, TaiJiao

    2015-09-01

    The human influenza A (H3N2) virus dominated the 2014-2015 winter season in many countries and caused massive morbidity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 (A/Switzerland/9715293/2013-like strains) and HK14 (A/Hong Kong/5738/2014-like strains), co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in mainland China, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an important role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains. PMID:26219513

  13. Inter‐ and intraspecies transmission of canine influenza virus (H3N2) in dogs, cats, and ferrets

    PubMed Central

    Kim, Hyekwon; Song, Daesub; Moon, Hyoungjoon; Yeom, Minjoo; Park, Seongjun; Hong, Minki; Na, Woonseong; Webby, Richard J.; Webster, Robert G.; Park, Bongkyun; Kim, Jeong‐Ki; Kang, Bokyu

    2012-01-01

    Background  The emergence of zoonotic viruses in domestic animals is a significant public health concern. Canine influenza virus (CIV) H3N2 is a virus that can infect companion animals and is, therefore, a potential public health concern. Objective  This study investigated the inter‐ and intraspecies transmission of CIV among dogs, cats, and ferrets, under laboratory conditions, to determine whether transmission of the virus was possible between as well as within these domestic animal species. Method  The transmission routes for inter‐ and intraspecies transmission were airborne and direct contact, respectively. Transmission was conducted through intranasal infection of dogs followed by exposure to either cats or ferrets and by comingling infected and naïve animals of the same species. Results  The interspecies transmission of CIV H3N2 via airborne was only observed from dogs to cats and not from dogs to ferrets. However, direct intranasal infection of either cats or ferrets with CIV could induce influenza‐like clinical signs, viral shedding, and serological responses. Additionally, naïve cats and ferrets could be infected by CIV via direct contact with infected animals of the same species. Conclusion  Cats appear to be another susceptible host of CIV H3N2, whereas ferrets are not likely natural hosts. The molecular‐based mechanism of interspecies and intraspecies transmission of CIV H3N2 should be further studied. PMID:22616918

  14. H3N2 influenza viruses from domestic chickens in Italy: an increasing role for chickens in the ecology of influenza?

    PubMed

    Campitelli, Laura; Fabiani, Concetta; Puzelli, Simona; Fioretti, Alessandro; Foni, Emanuela; De Marco, Alessandra; Krauss, Scott; Webster, Robert G; Donatelli, Isabella

    2002-02-01

    In Italy, multiple H3N2 influenza viruses were isolated from chickens with mild respiratory disease and were shown to replicate in the respiratory tracts of experimentally infected chickens; this finding is the first to show that H3N2 influenza viruses can replicate and cause disease in chickens. H3N2 influenza viruses in pigs on nearby farms seemed a likely source of the virus; however, antigenic and molecular analyses revealed that the gene segments of the viruses in chickens were mainly of Eurasian avian origin and were distinguishable from those isolated from pigs and wild aquatic birds in Italy. Thus, several different H3 influenza viruses were circulating in Italy, but we failed to identify the source of the chicken H3N2 influenza viruses that have disappeared subsequently from Italian poultry. Until recently, the transmission of influenza viruses (other than the H5 and H7 subtypes) from their reservoir in aquatic birds to chickens was rarely detected and highly pathogenic and non-pathogenic viruses were considered to be restricted to poultry species. However, the recent reports of the transmission of H9N2 and H5N1 influenza viruses to chickens in Hong Kong and, subsequently, to humans and our findings of the transmission of H3N2 influenza viruses to domestic chickens in Italy suggest an increased role for chickens as an intermediate host in the ecology of influenza.

  15. Antigenic Maps of Influenza A(H3N2) Produced With Human Antisera Obtained After Primary Infection

    PubMed Central

    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

    Background 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. Methods 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. Results 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. Conclusions 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. PMID:26142433

  16. Unifying Viral Genetics and Human Transportation Data to Predict the Global Transmission Dynamics of Human Influenza H3N2

    PubMed Central

    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.

    2014-01-01

    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

  17. 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.

  18. Complete genome sequence of an avian-origin H3N2 canine influenza virus isolated from dogs in South Korea.

    PubMed

    Park, Seong-Jun; Moon, Hyoung-Joon; Kang, Bo-Kyu; Hong, Minki; Na, Woonseong; Kim, Jeong-Ki; Poo, Haryoung; Park, Bong-Kyun; Song, Dae-Sub

    2012-09-01

    An avian-origin Korean H3N2 canine influenza virus (CIV) strain, designated A/canine/Korea/01/2007 (H3N2), was isolated from nasal swabs of pet dogs exhibiting severe respiratory syndrome in 2007. In the present study, we report the first complete genome sequence containing 3' and 5' noncoding regions (NCRs) of H3N2 CIV, which will provide important insights into the molecular basis of pathogenesis, transmission, and evolution of CIV.

  19. Investigation of an Influenza A (H3N2) outbreak in evacuation centres following the Great East Japan earthquake, 2011

    PubMed Central

    2014-01-01

    Background The Great East Japan Earthquake of magnitude 9.0 that struck on 11 March 2011 resulted in more than 18000 deaths or cases of missing persons. The large-scale tsunami that followed the earthquake devastated many coastal areas of the Tohoku region, including Miyagi Prefecture, and many residents of the tsunami-affected areas were compelled to reside in evacuation centres (ECs). In Japan, seasonal influenza epidemics usually occur between December and March. At the time of the Great East Japan Earthquake on 11 March 2011, influenza A (H3N2) was still circulating and there was a heightened concern regarding severe outbreaks due to influenza A (H3N2). Methods After local hospital staff and public health nurses detected influenza cases among the evacuees, an outbreak investigation was conducted in five ECs that had reported at least one influenza case from 23 March to 11 April 2011. Cases were confirmed by point-of-care tests and those residues were obtained and subjected to reverse transcription PCR and/or real time RT-PCR for sub-typing of influenza. Results There were 105 confirmed cases detected during the study period with a mean attack rate of 5.3% (range, 0.8%–11.1%). An epidemiological tree for two ECs demonstrated same-room and familial links that accounted for 88.5% of cases. The majority of cases occurred in those aged 15-64 years, who were likely to have engaged in search and rescue activities. No deaths were reported in this outbreak. Familial link accounted for on average 40.5% of influenza cases in two ECs and rooms where two or more cases were reported accounted for on average 85% in those ECs. A combination of preventative measures, including case cohorting, personal hygiene, wearing masks, and early detection and treatment, were implemented during the outbreak period. Conclusions Influenza can cause outbreaks in a disaster setting when the disaster occurs during an epidemic influenza season. The transmission route is more likely to be

  20. 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.

  1. 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 Neu5Aca2–3Galb1–4(Fuca-)-like or Neu5Aca2–3Galb1–3(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 Neu5Aca2–3Galb1–4(Fuca-) or Neu5Aca2–3Galb1–3(Fuca-)-like structures that are present in dogs. PMID:23994833

  2. Prevalence, genetic drift of haemagglutinin, and antiviral resistance of influenza A/H3N2 viruses circulating in Shanghai in children during 2009-2012.

    PubMed

    Cai, Jiehao; Wang, Xiangshi; Zhao, Baihui; Yao, Weilei; Wang, Xiaohong; Zhu, Qirong; Zeng, Mei

    2014-06-01

    Influenza A/H3N2 viruses are associated with severe epidemics. Antiviral resistance and continued antigenic drift are the major concerns regarding prophylaxis and treatment of influenza. The objectives of this study were to investigate the prevalence and frequency of antiviral drug resistance in influenza A/H3N2 viruses circulating among Shanghainese children from June 2009 to May 2012 and to understand the genetic evolution of the hemagglutinin (HA) epitopes. Nasopharyngeal/throat swabs were collected from outpatients with influenza-like illness. Of the 3,475 children tested, 344 (9.9%) were positive for influenza A/H3N2 viruses. Epidemics of influenza A/H3N2 occurred in July-September 2009, August 2010-January 2011, and November 2011-May 2012. The 71 A/H3N2-positive specimens were sequenced to characterize the genotypic antiviral resistance and genetic drift in the HA epitopes. All of the 71 A/H3N2 viruses sequenced were genotypically resistant to adamantine but sensitive to oseltamivir. The HA1 sequence analysis revealed that the A/H3N2 viruses underwent constant mutations in the HA antigenic sites over the three seasons compared with the corresponding vaccine strains, and amino acid changes in at least three epitopes were observed each season. Phylogenic analyses indicated that the A/H3N2 strains circulating in Shanghai fell into clades different from those of the corresponding seasonal vaccine strains and were grouped into the A/Perth/16/2009 genetic clade and the A/Victoria/208/2009 genetic clades 3B, 3C, and 5. The continuous monitoring of genetic drift and antiviral resistance of influenza viruses is important for the management of influenza and for updating the vaccine composition.

  3. High frequency of amantadine-resistant influenza A (H3N2) viruses in the 2005-2006 season and rapid detection of amantadine-resistant influenza A (H3N2) viruses by MAMA-PCR.

    PubMed

    Hata, Mami; Tsuzuki, Masako; Goto, Yasuhiro; Kumagai, Norimichi; Harada, Miki; Hashimoto, Michiko; Tanaka, Seidai; Sakae, Kenji; Kimura, Takashi; Minagawa, Hiroko; Miyazaki, Yutaka

    2007-07-01

    Using the newly designed mismatch amplification mutation assay (MAMA) PCR, we demonstrated the high frequency of amantadine-resistant influenza A (H3N2) viruses isolated during the 2005-2006 season by detecting the mutation at amino acid position 31 of the M2 protein (S31N). Further, phylogenetic analyses of the HA1 sequences of the S31N viruses revealed that they comprised a clonal lineage that would result in the common characteristic amino acid changes at positions 193 (Ser to Phe) and 225 (Asp to Asn) of the HA protein. We also demonstrated that the S31N/S193F/D225N viruses had already emerged in Aichi Prefecture by the end of the previous 2004-2005 season.

  4. 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

  5. Global and quantitative proteomic analysis of dogs infected by avian-like H3N2 canine influenza virus

    PubMed Central

    Su, Shuo; Tian, Jin; Hong, Malin; Zhou, Pei; Lu, Gang; Zhu, Huachen; Zhang, Guihong; Lai, Alexander; Li, Shoujun

    2015-01-01

    Canine influenza virus A (H3N2) is a newly emerged etiological agent for respiratory infections in dogs. The mechanism of interspecies transmission from avian to canine species and the development of diseases in this new host remain to be explored. To investigate this, we conducted a differential proteomics study in 2-month-old beagles inoculated intranasally with 106 TCID50 of A/canine/Guangdong/01/2006 (H3N2) virus. Lung sections excised at 12 h post-inoculation (hpi), 4 days, and 7 days post-inoculation (dpi) were processed for global and quantitative analysis of differentially expressed proteins. A total of 17,796 proteins were identified at different time points. About 1.6% was differentially expressed between normal and infected samples. Of these, 23, 27, and 136 polypeptides were up-regulated, and 14, 18, and 123 polypeptides were down-regulated, at 12 hpi, 4 dpi, and 7 dpi, respectively. Vann diagram analysis indicated that 17 proteins were up-regulated and one was down-regulated at all three time points. Selected proteins were validated by real-time PCR and by Western blot. Our results show that apoptosis and cytoskeleton-associated proteins expression was suppressed, whereas interferon-induced proteins plus other innate immunity proteins were induced after the infection. Understanding of the interactions between virus and the host will provide insights into the basis of interspecies transmission, adaptation, and virus pathogenicity. PMID:25883591

  6. Antigenic Drift of A/H3N2/Virus and Circulation of Influenza-Like Viruses During the 2014/2015 Influenza Season in Poland.

    PubMed

    Bednarska, K; Hallmann-Szelińska, E; Kondratiuk, K; Brydak, L B

    2016-01-01

    Morbidity rates of influenza could be greatly reduced due to vaccination. However, the virus is able to evolve through genetic mutations, which is why vaccines with updated composition are necessary every season. Their effectiveness depends on whether there is a good antigenic match between circulating viruses and vaccine strains. In Poland, the 2014/2015 influenza epidemic started in week 5 (January/February) of 2015 and continued until week 17 (April) of 2015. The influenza activity was moderate with the highest incidence of influence-like illness at week 10/2015 (March). During that season, antigenic drift of influenza virus A/H3N2/ occurred causing higher rates of A/H3N2/ infections. Among the 2416 tested specimens, 22.6 % of influenza cases were positive for A/H3N2/, while A/H1N1/pdm09 constituted 14.6 % cases. Influenza A viruses were detected in co-circulation with influenza B viruses; the latter amounted to 34.1 % of all influenza detections. Other detected causes of influenza-like illness consisted of respiratory syncytial virus (RSV), being predominant, and, sporadically, human coronavirus, parainfluenza 1-3, rhinovirus, and adenovirus. Despite low vaccine effectiveness of solely one component, A/H3N2/, the vaccine could mitigate or shorten the length of influenza infection and reduce the number of severe outcomes and mortality. Thus, vaccination against influenza remains the most effective way to prevent illness and possibly fatal outcomes. PMID:26956457

  7. Multiple Influenza A (H3N2) Mutations Conferring Resistance to Neuraminidase Inhibitors in a Bone Marrow Transplant Recipient

    PubMed Central

    Eshaghi, Alireza; Shalhoub, Sarah; Rosenfeld, Paul; Li, Aimin; Higgins, Rachel R.; Stogios, Peter J.; Savchenko, Alexei; Bastien, Nathalie; Li, Yan; Rotstein, Coleman

    2014-01-01

    Immunocompromised patients are predisposed to infections caused by influenza virus. Influenza virus may produce considerable morbidity, including protracted illness and prolonged viral shedding in these patients, thus prompting higher doses and prolonged courses of antiviral therapy. This approach may promote the emergence of resistant strains. Characterization of neuraminidase (NA) inhibitor (NAI)-resistant strains of influenza A virus is essential for documenting causes of resistance. In this study, using quantitative real-time PCR along with conventional Sanger sequencing, we identified an NAI-resistant strain of influenza A (H3N2) virus in an immunocompromised patient. In-depth analysis by deep gene sequencing revealed that various known markers of antiviral resistance, including transient R292K and Q136K substitutions and a sustained E119K (N2 numbering) substitution in the NA protein emerged during prolonged antiviral therapy. In addition, a combination of a 4-amino-acid deletion at residues 245 to 248 (Δ245-248) accompanied by the E119V substitution occurred, causing resistance to or reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir). Resistant variants within a pool of viral quasispecies arose during combined antiviral treatment. More research is needed to understand the interplay of drug resistance mutations, viral fitness, and transmission. PMID:25246391

  8. 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.

  9. Complete Genome Sequence of a Canine-Origin H3N2 Feline Influenza Virus Isolated from Domestic Cats in South Korea.

    PubMed

    Park, Seong-Jun; Kang, Bo-Kyu; Jeoung, Hye-Young; Moon, Hyoung-Joon; Hong, Minki; Na, Woonseong; Park, Bong-Kyun; Poo, Haryoung; Kim, Jeong-Ki; An, Dong-Jun; Song, Dae-Sub

    2013-01-01

    A canine-origin Korean H3N2 feline influenza virus (FIV), A/feline/Korea/01/2010 (H3N2), was isolated in 2010 from a dead cat with severe respiratory disease. Here, we report the first complete genome sequence of this virus, containing 3' and 5' noncoding regions, which will help elucidate the molecular basis of the pathogenesis, transmission, and evolution of FIV.

  10. Isolation of a novel H3N2 influenza virus containing a gene of H9N2 avian influenza in a dog in South Korea in 2015.

    PubMed

    Lee, In Hong; Le, Tran Bac; Kim, Hyun Soo; Seo, Sang Heui

    2016-02-01

    We isolated a serotype H3N2 influenza virus from a dog with severe respiratory distress in an animal clinic in South Korea in 2015 and characterized the sequences of its eight genes. The following seven genes were derived from canine influenza virus: PB2, PB1, HA, NP, NA, M, and NS. However, the PA gene was derived from avian H9N2 influenza virus that is circulating in poultry in Korea. These findings suggest that the continued surveillance of the influenza virus in dogs is warranted because humans have close contact with dogs, which may promote viral transmission.

  11. Susceptibility of a yak to influenza A viruses and presence of H3N2 antibodies in animals in Nepal and India.

    PubMed

    Graves, I L; Pyakural, S; Sousa, V O

    1974-01-01

    Naturally acquired antibody to H3N2 human influenza antigens was found in a yak-zebu crossbred in Nepal. Serial inoculation of a yak, negative for antibody, produced a response to A/Hong Kong/1/68 (H3N2), A/England/42/72 (H3N2), and A/Prague/1/56 (Heq1 Neq1) influenzavirus strains. Single radial diffusion tests showed that cattle and goats in West Bengal, India, and water buffaloes and cattle in Kathmandu, Nepal, also had antibodies against the H3N2 antigens. Haemagglutination-inhibition antibodies to equine influenzaviruses were not found in human, goat, cattle, chicken, and dog sera, nor were antibodies to avian viruses found in human or equine serum.

  12. An influenza reassortant with polymerase of pH1N1 and NS gene of H3N2 influenza A virus is attenuated in vivo

    PubMed Central

    Shelton, Holly; Smith, Matt; Hartgroves, Lorian; Stilwell, Peter; Roberts, Kim; Johnson, Ben

    2012-01-01

    Influenza viruses readily mutate by accumulating point mutations and also by reassortment in which they acquire whole gene segments from another virus in a co-infected host. The NS1 gene is a major virulence factor of influenza A virus. The effects of changes in NS1 sequence depend on the influenza polymerase constellation. Here, we investigated the consequences of a virus with the polymerase of pandemic H1N1 2009 acquiring an NS gene segment derived from a seasonal influenza A H3N2 virus, a combination that might arise during natural reassortment of viruses that currently circulate in humans. We generated recombinant influenza viruses with surface HA and NA genes and matrix M gene segment from A/PR/8/34 virus, but different combinations of polymerase and NS genes. Thus, any changes in phenotype were not due to differences in receptor use, entry, uncoating or virus release. In Madin–Darby canine kidney (MDCK) cells, the virus with the NS gene from the H3N2 parent showed enhanced replication, probably a result of increased control of the interferon response. However, in mice the same virus was attenuated in comparison with the virus containing homologous pH1N1 polymerase and NS genes. Levels of viral RNA during single-cycles of replication were lower for the virus with H3N2 NS, and this virus reached lower titres in the lungs of infected mice. Thus, virus with pH1N1 polymerase genes did not increase its virulence by acquiring the H3N2 NS gene segment, and MDCK cells were a poor predictor of the outcome of infection in vivo. PMID:22323532

  13. Safety and Immunogenicity of Cell Culture-Derived A/H3N2 Variant Influenza Vaccines: A Phase I Randomized, Observer-Blind, Dose-Ranging Study

    PubMed Central

    Johnson, Casey; Hohenboken, Matthew; Poling, Terry; Jaehnig, Peter; Kanesa-thasan, Niranjan

    2015-01-01

    Background. A/H3N2 variant (H3N2v) influenza may sustain human-to-human transmission, and an available candidate vaccine would be important. Methods. In this phase I, randomized, observer-blind, dose-ranging study, 627 healthy subjects ≥3 years of age were randomized to receive 2 vaccinations with H3N2c cell-culture-derived vaccine doses containing 3.75 µg, 7.5 µg, or 15 µg hemagglutinin antigen of H3N2v with or without MF59 (registered trademark of Novartis AG) adjuvant (an oil-in-water emulsion). This paper reports Day 43 planned interim data. Results. Single MF59-adjuvanted H3N2c doses elicited immune responses in almost all subjects regardless of antigen and adjuvant dose; the Center for Biologics Evaluation Research and Review (CBER) licensure criteria were met for all groups. Subjects with prevaccination hemagglutination inhibition titers <10 and children 3–<9 years achieve CBER criteria only after receiving 2 doses of nonadjuvanted H3N2c vaccine. Highest antibody titers were observed in the 7.5 µg + 0.25 mL MF59 groups in all age cohorts. MF59-adjuvanted H3N2c vaccines showed the highest rates of solicited local and systemic events, predominately mild or moderate. Conclusions. A single dose of H3N2c vaccine may be immunogenic and supports further development of MF59-adjuvanted H3N2c vaccines, especially for pediatric populations. Clinical Trials Registration. ClinicalTrials.gov identifier NCT01855945 (http://clinicaltrials.gov/ct2/show/NCT01855945). PMID:25538277

  14. Discordant antigenic drift of neuraminidase and hemagglutinin in H1N1 and H3N2 influenza viruses

    PubMed Central

    Sandbulte, Matthew R.; Westgeest, Kim B.; Gao, Jin; Xu, Xiyan; Klimov, Alexander I.; Russell, Colin A.; Burke, David F.; Smith, Derek J.; Fouchier, Ron A. M.; Eichelberger, Maryna C.

    2011-01-01

    Seasonal epidemics caused by influenza virus are driven by antigenic changes (drift) in viral surface glycoproteins that allow evasion from preexisting humoral immunity. Antigenic drift is a feature of not only the hemagglutinin (HA), but also of neuraminidase (NA). We have evaluated the antigenic evolution of each protein in H1N1 and H3N2 viruses used in vaccine formulations during the last 15 y by analysis of HA and NA inhibition titers and antigenic cartography. As previously shown for HA, genetic changes in NA did not always lead to an antigenic change. The noncontinuous pattern of NA drift did not correspond closely with HA drift in either subtype. Although NA drift was demonstrated using ferret sera, we show that these changes also impact recognition by NA-inhibiting antibodies in human sera. Remarkably, a single point mutation in the NA of A/Brisbane/59/2007 was primarily responsible for the lack of inhibition by polyclonal antibodies specific for earlier strains. These data underscore the importance of NA inhibition testing to define antigenic drift when there are sequence changes in NA. PMID:22143798

  15. Genetic Characterization of an Ancestral Strain of the Avian-Origin H3N2 Canine Influenza Virus Currently Circulating in East Asia.

    PubMed

    Kim, Jeong-Ki; Nam, Jeong-Hyun; Lyoo, Kwang-Soo; Moon, Hyoungjoon; Na, Woonsung; Song, Eun-Jung; Yeom, Minjoo; Shim, Sang-Mu; Jeong, Dae Gwin; An, Dong-Jun; Kang, Bo-Kyu; Song, Daesub

    2016-06-28

    H3N2 canine influenza virus emerged in South Korea in 2007 and subsequently spread to China and Thailand, causing epidemic or endemic respiratory diseases in dogs. Through intermammalian species transmission, the virus has also infected cats. However, no direct evidence of significant genetic evolution has been reported since its first emergence. Here, we describe in depth the genetic and molecular characteristics of the ancestral strain (i.e., the first virus isolate from South Korea) of the H3N2 canine influenza virus currently circulating in East Asia. PMID:27012241

  16. Genetic Characterization of an Ancestral Strain of the Avian-Origin H3N2 Canine Influenza Virus Currently Circulating in East Asia.

    PubMed

    Kim, Jeong-Ki; Nam, Jeong-Hyun; Lyoo, Kwang-Soo; Moon, Hyoungjoon; Na, Woonsung; Song, Eun-Jung; Yeom, Minjoo; Shim, Sang-Mu; Jeong, Dae Gwin; An, Dong-Jun; Kang, Bo-Kyu; Song, Daesub

    2016-06-28

    H3N2 canine influenza virus emerged in South Korea in 2007 and subsequently spread to China and Thailand, causing epidemic or endemic respiratory diseases in dogs. Through intermammalian species transmission, the virus has also infected cats. However, no direct evidence of significant genetic evolution has been reported since its first emergence. Here, we describe in depth the genetic and molecular characteristics of the ancestral strain (i.e., the first virus isolate from South Korea) of the H3N2 canine influenza virus currently circulating in East Asia.

  17. Using multiple linear regression and physicochemical changes of amino acid mutations to predict antigenic variants of influenza A/H3N2 viruses.

    PubMed

    Cui, Haibo; Wei, Xiaomei; Huang, Yu; Hu, Bin; Fang, Yaping; Wang, Jia

    2014-01-01

    Among human influenza viruses, strain A/H3N2 accounts for over a quarter of a million deaths annually. Antigenic variants of these viruses often render current vaccinations ineffective and lead to repeated infections. In this study, a computational model was developed to predict antigenic variants of the A/H3N2 strain. First, 18 critical antigenic amino acids in the hemagglutinin (HA) protein were recognized using a scoring method combining phi (ϕ) coefficient and information entropy. Next, a prediction model was developed by integrating multiple linear regression method with eight types of physicochemical changes in critical amino acid positions. When compared to other three known models, our prediction model achieved the best performance not only on the training dataset but also on the commonly-used testing dataset composed of 31878 antigenic relationships of the H3N2 influenza virus.

  18. 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.

  19. Assessing Antigenic Drift of Seasonal Influenza A(H3N2) and A(H1N1)pdm09 Viruses.

    PubMed

    Tewawong, Nipaporn; Prachayangprecha, Slinporn; Vichiwattana, Preeyaporn; Korkong, Sumeth; Klinfueng, Sirapa; Vongpunsawad, Sompong; Thongmee, Thanunrat; Theamboonlers, Apiradee; Poovorawan, Yong

    2015-01-01

    Under selective pressure from the host immune system, antigenic epitopes of influenza virus hemagglutinin (HA) have continually evolved to escape antibody recognition, termed antigenic drift. We analyzed the genomes of influenza A(H3N2) and A(H1N1)pdm09 virus strains circulating in Thailand between 2010 and 2014 and assessed how well the yearly vaccine strains recommended for the southern hemisphere matched them. We amplified and sequenced the HA gene of 120 A(H3N2) and 81 A(H1N1)pdm09 influenza virus samples obtained from respiratory specimens and calculated the perfect-match vaccine efficacy using the pepitope model, which quantitated the antigenic drift in the dominant epitope of HA. Phylogenetic analysis of the A(H3N2) HA1 genes classified most strains into genetic clades 1, 3A, 3B, and 3C. The A(H3N2) strains from the 2013 and 2014 seasons showed very low to moderate vaccine efficacy and demonstrated antigenic drift from epitopes C and A to epitope B. Meanwhile, most A(H1N1)pdm09 strains from the 2012-2014 seasons belonged to genetic clades 6A, 6B, and 6C and displayed the dominant epitope mutations at epitopes B and E. Finally, the vaccine efficacy for A(H1N1)pdm09 (79.6-93.4%) was generally higher than that of A(H3N2). These findings further confirmed the accelerating antigenic drift of the circulating influenza A(H3N2) in recent years.

  20. The Proteolytic Activation of (H3N2) Influenza A Virus Hemagglutinin Is Facilitated by Different Type II Transmembrane Serine Proteases

    PubMed Central

    Kühn, Nora; Bergmann, Silke; Kösterke, Nadine; Lambertz, Ruth L. O.; Keppner, Anna; van den Brand, Judith M. A.; Weiß, Siegfried; Hummler, Edith; Hatesuer, Bastian

    2016-01-01

    ABSTRACT Cleavage of influenza virus hemagglutinin (HA) by host cell proteases is necessary for viral activation and infectivity. In humans and mice, members of the type II transmembrane protease family (TTSP), e.g., TMPRSS2, TMPRSS4, and TMPRSS11d (HAT), have been shown to cleave influenza virus HA for viral activation and infectivity in vitro. Recently, we reported that inactivation of a single HA-activating protease gene, Tmprss2, in knockout mice inhibits the spread of H1N1 influenza viruses. However, after infection of Tmprss2 knockout mice with an H3N2 influenza virus, only a slight increase in survival was observed, and mice still lost body weight. In this study, we investigated an additional trypsin-like protease, TMPRSS4. Both TMPRSS2 and TMPRSS4 are expressed in the same cell types of the mouse lung. Deletion of Tmprss4 alone in knockout mice does not protect them from body weight loss and death upon infection with H3N2 influenza virus. In contrast, Tmprss2−/− Tmprss4−/− double-knockout mice showed a remarkably reduced virus spread and lung pathology, in addition to reduced body weight loss and mortality. Thus, our results identified TMPRSS4 as a second host cell protease that, in addition to TMPRSS2, is able to activate the HA of H3N2 influenza virus in vivo. IMPORTANCE Influenza epidemics and recurring pandemics are responsible for significant global morbidity and mortality. Due to high variability of the virus genome, resistance to available antiviral drugs is frequently observed, and new targets for treatment of influenza are needed. Host cell factors essential for processing of the virus hemagglutinin represent very suitable drug targets because the virus is dependent on these host factors for replication. We reported previously that Tmprss2-deficient mice are protected against H1N1 virus infections, but only marginal protection against H3N2 virus infections was observed. Here we show that deletion of two host protease genes, Tmprss2 and

  1. Transmission of a 2009 pandemic influenza virus shows a sensitivity to temperature and humidity similar to that of an H3N2 seasonal strain.

    PubMed

    Steel, John; Palese, Peter; Lowen, Anice C

    2011-02-01

    In temperate regions of the world, influenza epidemics follow a highly regular seasonal pattern, in which activity peaks in midwinter. Consistently with this epidemiology, we have shown previously that the aerosol transmission of a seasonal H3N2 influenza virus is most efficient under cold, dry conditions. With the 2009 H1N1 pandemic, an exception to the standard seasonality of influenza developed: during 2009 in the Northern Hemisphere, an unusually high level of influenza virus activity over the spring and summer months was followed by a widespread epidemic which peaked in late October, approximately 2.5 months earlier than usual. Herein we show that aerosol transmission of a 2009 pandemic strain shows a dependence on relative humidity and temperature very similar to that of a seasonal H3N2 influenza virus. Our data indicate that the observed differences in the timings of outbreaks with regard to the seasons are most likely not due to intrinsic differences in transmission between the pandemic H1N1 and seasonal H3N2 influenza viruses.

  2. Antiviral susceptibility of variant influenza A(H3N2)v viruses isolated in the United States from 2011 to 2013.

    PubMed

    Sleeman, K; Mishin, V P; Guo, Z; Garten, R J; Balish, A; Fry, A M; Villanueva, J; Stevens, J; Gubareva, L V

    2014-01-01

    Since 2011, outbreaks caused by influenza A(H3N2) variant [A(H3N2)v] viruses have become a public health concern in the United States. The A(H3N2)v viruses share the A(H1N1)pdm09 M gene containing the marker of M2 blocker resistance, S31N, but do not contain any known molecular markers associated with resistance to neuraminidase (NA) inhibitors (NAIs). Using a fluorescent NA inhibition (NI) assay, the susceptibilities of recovered A(H3N2)v viruses (n=168) to FDA-approved (oseltamivir and zanamivir) and other (peramivir, laninamivir, and A-315675) NAIs were assessed. All A(H3N2)v viruses tested, with the exception of a single virus strain, A/Ohio/88/2012, isolated from an untreated patient, were susceptible to the NAIs tested. The A/Ohio/88/2012 virus contained two rare substitutions, S245N and S247P, in the NA and demonstrated reduced inhibition by oseltamivir (31-fold) and zanamivir (66-fold) in the NI assay. Using recombinant NA (recNA) proteins, S247P was shown to be responsible for the observed altered NAI susceptibility, in addition to an approximately 60% reduction in NA enzymatic activity. The S247P substitution has not been previously reported as a molecular marker of reduced susceptibility to the NAIs. Using cell culture assays, the investigational antiviral drugs nitazoxanide, favipiravir, and fludase were shown to inhibit the replication of A(H3N2)v viruses, including the virus with the S247P substitution in the NA. This report demonstrates the importance of continuous monitoring of susceptibility of zoonotic influenza viruses to available and investigational antiviral drugs.

  3. Progressive antigenic drift and phylogeny of human influenza A(H3N2) virus over five consecutive seasons (2009-2013) in Hangzhou, China.

    PubMed

    Shao, Tie-Juan; Li, Jun; Yu, Xin-Fen; Kou, Yu; Zhou, Yin-Yan; Qian, Xin

    2014-12-01

    Vaccine efficacy (VE) can be affected by progressive antigenic drift or any new reassortment of influenza viruses. To effectively track the evolution of human influenza A(H3N2) virus circulating in Hangzhou, China, a total of 65 clinical specimens were selected randomly from outpatients infected by A(H3N2) viruses during the study period from November 2009 to December 2013. The results of reduced VE and antigenic drift of the correspondent epitopes (C-D-E to A-B) suggest that the current vaccine provides suboptimal protection against the A(H3N2) strains circulating recently. Phylogenetic analysis of the entire HA and NA sequences demonstrated that these two genes underwent independent evolutionary pathways during recent seasons. The H3-based phylogenetic tree showed that a special strain A/Hangzhou/A289/2012 fell in a cluster among viruses with reduced VE predominantly circulating in 2013. Our findings underscore a possible early warning for the circulation of A(H3N2) variants with antigenic drift during the previous seasons.

  4. H1N1, but Not H3N2, Influenza A Virus Infection Protects Ferrets from H5N1 Encephalitis

    PubMed Central

    Wang, Guoji; Carter, Donald M.; Crevar, Corey J.; Ross, Ted M.; Wiley, Clayton A.

    2014-01-01

    ABSTRACT Seasonal influenza causes substantial morbidity and mortality because of efficient human-to-human spread. Rarely, zoonotic strains of influenza virus spread to humans, where they have the potential to mediate new pandemics with high mortality. We studied systemic viral spread after intranasal infection with highly pathogenic avian influenza virus (H5N1 [A/Viet Nam/1203/2004]) in ferrets with or without prior pandemic H1N1pdm09 (A/Mexico/4108/2009) or H3N2 (A/Victoria/361/2011) infection. After intranasal challenge with H5N1 influenza virus, naive ferrets rapidly succumbed to systemic infection. Animals challenged with H5N1 influenza virus greater than 3 months after recovering from an initial H1N1pdm09 infection survived H5N1 virus challenge and cleared virus from the respiratory tract 4 days after infection. However, a prolonged low-level infection of hematopoietic elements in the small bowel lamina propria, liver, and spleen was present for greater than 2 weeks postinfection, raising the potential for reassortment of influenza genes in a host infected with multiple strains of influenza. Animals previously infected with an H3N2 influenza virus succumbed to systemic disease and encephalitis after H5N1 virus challenge. These results indicate prior infection with different seasonal influenza strains leads to radically different protection from H5N1 challenge and fatal encephalitis. IMPORTANCE Seasonal influenza is efficiently transmitted from human to human, causing substantial morbidity and mortality. Rarely, zoonotic strains of influenza virus spread to humans, where they have the potential to mediate new pandemics with high mortality. Infection of naive ferrets with H5N1 avian influenza virus causes a rapid and lethal systemic disease. We studied systemic H5N1 viral spread after infection of ferrets with or without prior exposure to either of two seasonal influenza virus strains, H1N1 and H3N2. Ferrets previously infected with H1N1 survive H5N1 challenge

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  6. Comparative analyses of pandemic H1N1 and seasonal H1N1, H3N2, and influenza B infections depict distinct clinical pictures in ferrets.

    PubMed

    Huang, Stephen S H; Banner, David; Fang, Yuan; Ng, Derek C K; Kanagasabai, Thirumagal; Kelvin, David J; Kelvin, Alyson A

    2011-01-01

    Influenza A and B infections are a worldwide health concern to both humans and animals. High genetic evolution rates of the influenza virus allow the constant emergence of new strains and cause illness variation. Since human influenza infections are often complicated by secondary factors such as age and underlying medical conditions, strain or subtype specific clinical features are difficult to assess. Here we infected ferrets with 13 currently circulating influenza strains (including strains of pandemic 2009 H1N1 [H1N1pdm] and seasonal A/H1N1, A/H3N2, and B viruses). The clinical parameters were measured daily for 14 days in stable environmental conditions to compare clinical characteristics. We found that H1N1pdm strains had a more severe physiological impact than all season strains where pandemic A/California/07/2009 was the most clinically pathogenic pandemic strain. The most serious illness among seasonal A/H1N1 and A/H3N2 groups was caused by A/Solomon Islands/03/2006 and A/Perth/16/2009, respectively. Among the 13 studied strains, B/Hubei-Wujiagang/158/2009 presented the mildest clinical symptoms. We have also discovered that disease severity (by clinical illness and histopathology) correlated with influenza specific antibody response but not viral replication in the upper respiratory tract. H1N1pdm induced the highest and most rapid antibody response followed by seasonal A/H3N2, seasonal A/H1N1 and seasonal influenza B (with B/Hubei-Wujiagang/158/2009 inducing the weakest response). Our study is the first to compare the clinical features of multiple circulating influenza strains in ferrets. These findings will help to characterize the clinical pictures of specific influenza strains as well as give insights into the development and administration of appropriate influenza therapeutics.

  7. Immunopathogenic and antibacterial effects of H3N2 influenza A virus PB1-F2 map to amino acid residues 62, 75, 79, and 82.

    PubMed

    Alymova, Irina V; Green, Amanda M; van de Velde, Nicholas; McAuley, Julie L; Boyd, Kelli L; Ghoneim, Hazem E; McCullers, Jonathan A

    2011-12-01

    The influenza A virus protein PB1-F2 has been linked to the pathogenesis of both primary viral and secondary bacterial infections. H3N2 viruses have historically expressed full-length PB1-F2 proteins with either proinflammatory (e.g., from influenza A/Hong Kong/1/1968 virus) or noninflammatory (e.g., from influenza A/Wuhan/359/1995 virus) properties. Using synthetic peptides derived from the active C-terminal portion of the PB1-F2 protein from those two viruses, we mapped the proinflammatory domain to amino acid residues L62, R75, R79, and L82 and then determined the role of that domain in H3N2 influenza virus pathogenicity. PB1-F2-derived peptides containing that proinflammatory motif caused significant morbidity, mortality, and pulmonary inflammation in mice, manifesting as increased acute lung injury and the presence of proinflammatory cytokines and inflammatory cells in the lungs compared to peptides lacking this motif, and better supported bacterial infection with Streptococcus pneumoniae. Infections of mice with an otherwise isogenic virus engineered to contain this proinflammatory sequence in PB1-F2 demonstrated increased morbidity resulting from primary viral infections and enhanced development of secondary bacterial pneumonia. The presence of the PB1-F2 noninflammatory (P62, H75, Q79, and S82) sequence in the wild-type virus mediated an antibacterial effect. These data suggest that loss of the inflammatory PB1-F2 phenotype that supports bacterial superinfection during adaptation of H3N2 viruses to humans, coupled with acquisition of antibacterial activity, contributes to the relatively diminished frequency of severe infections seen with seasonal H3N2 influenza viruses in recent decades compared to their first 2 decades of circulation.

  8. Accelerating Influenza Research: Vaccines, Antivirals, Immunomodulators and Monoclonal Antibodies. The Manufacture of a New Wild-Type H3N2 Virus for the Human Viral Challenge Model

    PubMed Central

    Fullen, Daniel J.; Noulin, Nicolas; Catchpole, Andrew; Fathi, Hosnieh; Murray, Edward J.; Mann, Alex; Eze, Kingsley; Balaratnam, Ganesh; Borley, Daryl W.; Gilbert, Anthony; Lambkin-Williams, Rob

    2016-01-01

    Background Influenza and its associated diseases are a major cause of morbidity and mortality. The United States Advisory Committee on Immunization Practices recommends influenza vaccination for everyone over 6 months of age. The failure of the flu vaccine in 2014–2015 demonstrates the need for a model that allows the rapid development of novel antivirals, universal/intra-seasonal vaccines, immunomodulators, monoclonal antibodies and other novel treatments. To this end we manufactured a new H3N2 influenza virus in compliance with Good Manufacturing Practice for use in the Human Viral Challenge Model. Methods and Strain Selection We chose an H3N2 influenza subtype, rather than H1N1, given that this strain has the most substantial impact in terms of morbidity or mortality annually as described by the Centre for Disease Control. We first subjected the virus batch to rigorous adventitious agent testing, confirmed the virus to be wild-type by Sanger sequencing and determined the virus titres appropriate for human use via the established ferret model. We built on our previous experience with other H3N2 and H1N1 viruses to develop this unique model. Human Challenge and Conclusions We conducted an initial safety and characterisation study in healthy adult volunteers, utilising our unique clinical quarantine facility in London, UK. In this study we demonstrated this new influenza (H3N2) challenge virus to be both safe and pathogenic with an appropriate level of disease in volunteers. Furthermore, by inoculating volunteers with a range of different inoculum titres, we established the minimum infectious titre required to achieve reproducible disease whilst ensuring a sensitive model that can be translated to design of subsequent field based studies. Trial Registration ClinicalTrials.gov NCT02525055 PMID:26761707

  9. Summary of Control Issues for Swine Influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple subtypes of endemic swine influenza virus (SIV) co-circulate in the U.S. and Canada (H3N2, H1N1, and H1N2 with a triple reassortant internal gene (TRIG) constellation derived from swine, avian and human influenza viruses). As a result of reassortment events and antigenic drift, four H1 SIV...

  10. Genetic analysis of H3N2 avian influenza viruses isolated from live poultry markets and poultry slaughterhouses in Shanghai, China in 2013.

    PubMed

    Yang, Dequan; Liu, Jian; Ju, Houbin; Ge, Feifei; Wang, Jian; Li, Xin; Zhou, Jinping; Liu, Peihong

    2015-08-01

    Five H3N2 avian influenza viruses (AIVs) were isolated from live poultry markets (LPMs) and poultry slaughterhouses in Shanghai, China in 2013. All viruses were characterized by whole-genome sequencing with subsequent genetic comparison and phylogenetic analysis. The hemagglutinin cleavage site of all viruses indicated that the five strains were low-pathogenic AIVs. Phylogenetic analysis of all eight viral genes showed that the five H3N2 viruses clustered in the Eurasian lineage of influenza viruses. The eight genes showed evidence of reassortment events between these H3 subtype viruses and other subtype viruses, especially H5 and H7 subtypes, probably in pigeons, domestic ducks, and wild birds. These findings emphasized the importance of AIV surveillance in LPMs and poultry slaughterhouses for understanding the genesis and emergence of novel reassortants with pandemic potential. PMID:25899857

  11. Genetic analysis of H3N2 avian influenza viruses isolated from live poultry markets and poultry slaughterhouses in Shanghai, China in 2013.

    PubMed

    Yang, Dequan; Liu, Jian; Ju, Houbin; Ge, Feifei; Wang, Jian; Li, Xin; Zhou, Jinping; Liu, Peihong

    2015-08-01

    Five H3N2 avian influenza viruses (AIVs) were isolated from live poultry markets (LPMs) and poultry slaughterhouses in Shanghai, China in 2013. All viruses were characterized by whole-genome sequencing with subsequent genetic comparison and phylogenetic analysis. The hemagglutinin cleavage site of all viruses indicated that the five strains were low-pathogenic AIVs. Phylogenetic analysis of all eight viral genes showed that the five H3N2 viruses clustered in the Eurasian lineage of influenza viruses. The eight genes showed evidence of reassortment events between these H3 subtype viruses and other subtype viruses, especially H5 and H7 subtypes, probably in pigeons, domestic ducks, and wild birds. These findings emphasized the importance of AIV surveillance in LPMs and poultry slaughterhouses for understanding the genesis and emergence of novel reassortants with pandemic potential.

  12. Synthesis of 1,2,3-triazolyl nucleoside analogs as potential anti-influenza A (H3N2 subtype) virus agents.

    PubMed

    Elayadi, Hanane; Smietana, Michael; Vasseur, Jean J; Balzarini, Jan; Lazrek, Hassan B

    2014-02-01

    Montmorillonite K10 impregnated with copper dichloride and potassium iodide (CuCl2 /KI/K10) was used as catalyst in the cycloaddition of azides and propargylnucleobases, to provide the corresponding 1,4-disubstituted 1,2,3-triazoles in good yield. All compounds 16-23 were evaluated for their antiviral activity in vitro. Compound 18 showed moderate inhibition against influenza virus A (H3N2). PMID:24272912

  13. Analytical reactivity of 13 commercially available rapid influenza diagnostic tests with H3N2v and recently circulating influenza viruses

    PubMed Central

    Bose, Michael E; Sasman, Amy; Mei, Hong; McCaul, Kate C; Kramp, William J; Chen, Li-Mei; Shively, Roxanne; Williams, Tracie L; Beck, Eric T; Henrickson, Kelly J

    2014-01-01

    Objectives Rapid influenza diagnostic tests (RIDTs) used widely in clinical practice are simple to use and provide results within 15 minutes; however, reported performance is variable, which causes concern when novel or variant viruses emerge. This study's goal was to assess the analytical reactivity of 13 RIDTs with recently circulating seasonal and H3N2v influenza viruses, using three different viral measures. Design Virus stocks were characterized by infectious dose (ID50) and nucleoprotein (NP) concentration, diluted at half-log dilutions, and tested with each RIDT and real-time RT-PCR. Results Strong correlation was observed between NP concentration and RIDT reactivity; however, only weak correlation was seen with ID50 or Ct values. Only four RIDTs detected viral NP at the lowest dilution for all influenza A viruses (IAV). Influenza A viruses not detected by more than one RIDT had lower NP levels. Of the 13 RIDTs, 9 had no significant differences in reactivity across IAV when compared to NP levels. Conclusions Previous reports of RIDT performance typically compare reactivity based on ID50 titers, which in this study correlated only weakly with proportional amounts of viral NP in prepared virus samples. In the context of the strong correlation of RIDT reactivity with NP concentration, H3N2v was found to be as reactive as seasonal circulating IAV. While these findings may not reflect clinical performance of these RIDTs, measuring NP concentration can be useful in the future to assess comparable reactivity of available RIDTs, or to assess reactivity with newly evolving or emerging viruses. PMID:24698134

  14. Comparative analysis of virulence of a novel, avian-origin H3N2 canine influenza virus in various host species.

    PubMed

    Lyoo, Kwang-Soo; Kim, Jeong-Ki; Kang, Bokyu; Moon, Hyoungjoon; Kim, Jongman; Song, Manki; Park, Bongkyun; Kim, Sang-Hyun; Webster, Robert G; Song, Daesub

    2015-01-01

    A novel avian-origin H3N2 canine influenza A virus (CIV) that showed high sequence similarities in hemagglutinin and neuraminidase genes with those of non-pathogenic avian influenza viruses was isolated in our routine surveillance program in South Korea. We previously reported that the pathogenicity of this strain could be reproduced in dogs and cats. In the present study, the host tropism of H3N2 CIV was examined by experimental inoculation into several host species, including chickens, pigs, mice, guinea pigs, and ferrets. The CIV infection resulted in no overt symptoms of disease in these host species. However, sero-conversion, virus shedding, and gross and histopathologic lung lesions were observed in guinea pig and ferrets but not in pigs, or mice. Based on the genetic similarity of our H3N2 CIV with currently circulating avian influenza viruses and the presence of α-2,3-linked rather than α-2,6-linked sialic acid receptors in the respiratory tract of dogs, we believed that this strain of CIV would have avian virus-like receptor specificity, but that seems to be contrary to our findings in the present study. Further studies are needed to determine the co-receptors of hemagglutinin or post-attachment factors related to virus internalization or pathogenesis in other animals.

  15. 2011–12 Seasonal Influenza Vaccines Effectiveness against Confirmed A(H3N2) Influenza Hospitalisation: Pooled Analysis from a European Network of Hospitals. A Pilot Study

    PubMed Central

    Rondy, Marc; Puig-Barbera, Joan; Launay, Odile; Duval, Xavier; Castilla, Jesús; Guevara, Marcela; Costanzo, Simona; de Gaetano Donati, Katleen; Moren, Alain

    2013-01-01

    Background Influenza vaccination strategies aim at protecting high-risk population from severe outcomes. Estimating the effectiveness of seasonal vaccines against influenza related hospitalisation is important to guide these strategies. Large sample size is needed to have precise estimate of influenza vaccine effectiveness (IVE) against severe outcomes. We assessed the feasibility of measuring seasonal IVE against hospitalisation with laboratory confirmed influenza through a network of 21 hospitals in the European Union. Methods We conducted a multicentre study in France (seven hospitals), Italy (one hospital), and Navarra (four hospitals) and Valencia (nine hospitals) regions in Spain. All ≥18 years hospitalised patients presenting an influenza-like illness within seven days were swabbed. Cases were patients RT-PCR positive for influenza A (H3N2); controls were patients negative for any influenza virus. Using logistic regression with study site as a fixed effect we calculated IVE adjusted for potential confounders. We restricted the analyses to those swabbed within four days. Results We included, 375 A(H3N2) cases and 770 controls. The overall adjusted IVE was 24.9% (95%CI–1.8;44.6). Among the target group for vaccination (N = 1058) the adjusted IVE was 28.8% (95%CI:2.8;47.9); it was respectively 36.8% (95%CI:−48.8; 73.1), 42.6% (95%CI:−16.5;71.7), 17.8%(95%CI:−40.8; 52.1) and 37.5% (95%CI:−22.8;68.2) in the age groups 18–64, 65–74, 75–84 and more than 84 years. Discussion Estimation of IVE based on the pooling of data obtained through a European network of hospitals was feasible. Our results suggest a low IVE against hospitalised confirmed influenza in 2011–12. The low IVE may be explained by a poor immune response in the high-risk population, imperfect match between vaccine and circulating strain or waning immunity due to a late season. Increased sample size within this network would allow more precise estimates and stratification of the

  16. The response to inactivated influenza A (H3N2) vaccines: the development and effect of antibodies to the surface antigens.

    PubMed Central

    Smith, A. F.; Davies, J. R.

    1977-01-01

    A controlled trial of influenza vaccines in a boys' public school from November 1970 to October 1975 provided an opportunity to study the response to vaccine and the effect on subsequent natural challenge in boys with differing natural experience of influenza A strains. The response to influenza A (H3N2) vaccines was assessed by estimating homotypic and heterotypic antibodies to the surface antigens. Previous natural experience of influenza A was found to influence vaccine response and the effect of natural challenge. The antibody response to revaccination with the same strain showed a progressively poorer response to second and third doses. The protectitive effect of naturally acquired and vaccine-induced antibodies was assessed during two outbreaks of influenza A which occurred in the trial period. PMID:266540

  17. Episodic nucleotide substitutions in seasonal influenza virus H3N2 can be explained by stochastic genealogical process without positive selection.

    PubMed

    Kim, Kangchon; Kim, Yuseob

    2015-03-01

    Nucleotide substitutions in the HA1 domain of seasonal influenza virus H3N2 occur in temporal clusters, which was interpreted as a result of recurrent selective sweeps underlying antigenic drift. However, classical theory by Watterson suggests that episodic substitutions are mainly due to stochastic genealogy combined with unique genetic structure of influenza virus: High mutation rate over a nonrecombining viral segment. This explains why even larger variance in the number of allelic fixations per year is observed in nonantigenic gene segments of H3N2 than in antigenic (hemagglutinin and neuraminidase) segments. Using simulation, we confirm that allelic substitutions at nonrecombining segments with high mutation rate become temporally clustered without selection. We conclude that temporal clustering of fixations, as it is primarily caused by inherent randomness in genealogical process at linked sites, cannot be used as an evidence of positive selection in the H3N2 population. This effect of linkage and high mutation rate should be carefully considered in analyzing the genomic patterns of allelic substitutions in asexually reproducing systems in general. PMID:25492497

  18. Mutations of two transmembrane cysteines of hemagglutinin (HA) from influenza A H3N2 virus affect HA thermal stability and fusion activity.

    PubMed

    Xu, Shun; Zhou, Jianqiang; Liu, Kang; Liu, Qiliang; Xue, Chunyi; Li, Xiaoming; Zheng, Jing; Luo, Dongyu; Cao, Yongchang

    2013-08-01

    Influenza A H3N2 virus caused 1968 Hong Kong influenza pandemic, and has since been one of the most prevalent seasonal influenza viruses in global populations, representing a credible pandemic candidate in future. Previous studies have established that the hemagglutinin (HA) protein is the predominant antigen and executes receptor binding and membrane fusion. Homologous sequence analysis of all HA subtypes of influenza viruses revealed that two cysteine residues (540 and 544) are uniquely present in the transmembrane domain (TM) of HA proteins from all influenza A H3N2 viruses. However, the functions of these two cysteines have not been fully studied. Here, we generated three mutants (C540S, C544L, and 2C/SL) to investigate the effects of the two TM cysteines on the biological functions of H3 HA. We herein presented evidences that the mutations of one or two of the cysteines did not affect the proper expressions of HA proteins in cells, and more importantly all mutant H3 HAs showed decreased thermal stability but increased fusion activity in comparison with wildtype HA. Our results taken together demonstrated that the two TM cysteines are important for the biological functions of H3 HA proteins.

  19. Simultaneous detection of influenza A, influenza B, and respiratory syncytial viruses and subtyping of influenza A H3N2 virus and H1N1 (2009) virus by multiplex real-time PCR.

    PubMed

    Chen, Yu; Cui, Dawei; Zheng, Shufa; Yang, Shigui; Tong, Jia; Yang, Dagan; Fan, Jian; Zhang, Jie; Lou, Bin; Li, Xuefen; Zhuge, Xiaoling; Ye, Bo; Chen, Baode; Mao, Weilin; Tan, Yajun; Xu, Genyun; Chen, Zhenjin; Chen, Nan; Li, Lanjuan

    2011-04-01

    A multiplex real-time PCR assay was developed to simultaneously detect and discriminate influenza A virus subtypes, including novel H1N1 (2009) and seasonal H3N2 virus, influenza B virus, and respiratory syncytial virus (RSV) in a single test tube, with detection sensitivity and specificity of 99% and 100%, respectively, for the four pathogens. PMID:21270233

  20. A new antigenic variant of human influenza A (H3N2) virus isolated from airport and community surveillance in Taiwan in early 2009.

    PubMed

    Yang, Ji-Rong; Lin, Chao-Hua; Chen, Chun-Jung; Liu, Jian-Liang; Huang, Yuan-Pin; Kuo, Chuan-Yi; Yao, Ching-Yuan; Hsu, Li-Ching; Lo, Je; Ho, Yu-Lin; Wu, Ho-Sheng; Liu, Ming-Tsan

    2010-07-01

    A new variant of influenza A H3N2 virus emerged in January 2009 and became the dominant strain in Taiwan in April 2009. The variant was also detected in imported cases from various regions, including East and Southeast Asia and North America, indicating that it has circulated globally. Compared to the 2009-2010 vaccine strain, A/Brisbane/10/2007, the hemagglutinin gene of this variant exhibited five substitutions, E62K, N144K, K158N, K173Q and N189K, which are located in the antigenic sites E, A, B, D and B respectively, and it was antigenically distinct from A/Brisbane/10/2007 with more than eight-fold titer reduction in the hemagglutination inhibition reaction. The A/Perth/16/2009 (H3N2)-like virus recommended by World Health Organization for use in the 2010 southern hemisphere and 2010-2011 northern influenza seasons exhibited the same substitutions like this new variant. In addition to regional or community influenza surveillance, the imported cases or airport fever screening surveillance may be a good resource to monitor the evolution of the virus and benefit the real-time information of global influenza circulation. PMID:20347893

  1. Mutations affecting the stability of the haemagglutinin molecule impair the immunogenicity of live attenuated H3N2 intranasal influenza vaccine candidates lacking NS1.

    PubMed

    Nakowitsch, Sabine; Wolschek, Markus; Morokutti, Alexander; Ruthsatz, Tanja; Krenn, Brigitte M; Ferko, Boris; Ferstl, Nicole; Triendl, Andrea; Muster, Thomas; Egorov, Andrej; Romanova, Julia

    2011-04-27

    The isolation and cultivation of human influenza viruses in embryonated hen eggs or cell lines often leads to amino acid substitutions in the haemagglutinin (HA) molecule. We found that the propagation of influenza A H3N2 viruses on Vero cells may trigger the appearance of HA destabilising mutations, affecting viral resistance to low pH or high temperature treatment. Two ΔNS1 reassortants, containing the HA sequences identical to the original human H3N2 influenza virus isolates were constructed. Passages of these viruses on Vero cells led to the appearance of single mutations in the HA(1) L194P or HA(2) G75R subunits that impaired virus stability. The original HA sequences and the stable phenotypes of the primary isolates were preserved if reassortants were passaged by infection at pH 5.6 and cultivation in medium at pH 6.5. Corresponding ΔNS1 reassortants were compared for their immunogenicity in ferrets upon intranasal immunisation. Vaccine candidates containing HA mutations demonstrated significantly lower immunogenicity compared to those without mutations. Thus, the retaining of the original HA sequences of human viruses during vaccine production might be crucial for the efficacy of live attenuated influenza vaccines.

  2. Safety and Immunogenicity of a Subvirion Monovalent Unadjuvanted Inactivated Influenza A(H3N2) Variant Vaccine in Healthy Persons ≥18 Years Old

    PubMed Central

    Keitel, Wendy A.; Jackson, Lisa A.; Edupuganti, Srilatha; Winokur, Patricia L.; Mulligan, Mark J.; Thornburg, Natalie J.; Patel, Shital M.; Rouphael, Nadine G.; Lai, Lilin; Bangaru, Sandhya; McNeal, Monica M.; Bellamy, Abbie R.; Hill, Heather R.; Bond, Nanette; Bosworth, Kathy; Brown, Janet; Banay, Jess; Cheesman, Coni; Lanford, Tracey; Munoz, Flor; Wells, Janet; Carste, Barb; Dunstan, Maya; Mathis, Angel; Parikh, Mihir; Phillips, C. Hallie; Spingola, Alyssa; Starkovich, Pat; Suyehira, Janice; Beck, Allison; Mask, Karen; Bower, Mary; Osinski, Eileen; Rimann, Nayoka; Turner, Pamela; Wang, DongLi; Stapleton, Jack; Won, Regina; Wagner, Nancy; Dull, Geraldine; Gerot, Necole; Reidy, Mary; Zhao, Dan; Segar, Ellen; Slaughter, James C.; McDonough, Megan; He, Fenhua; Salata, Robert; Meissner, Cody; Sheffield, Jeanne; Spigarelli, Michael; Greenberg, Stephen; Agrawal, Anoop; Dublin, Sascha; Arterburn, David; Rimland, David; Ribner, Bruce; Meier, Jeff; Buchanan, Wendy; Chang, Soju; Lambert, Linda; Murray, Suzanne; Riddle, Valerie; Spiro, David

    2015-01-01

    Background Variant influenza A(H3N2) viruses (H3N2v) have transmitted recently from pigs to humans in the United States. Vaccines strategies are needed. Methods Healthy adults received 2 doses of subvirion H3N2v vaccine (15 µg of hemagglutinin/dose) 21 days apart in this open-label trial. Serum hemagglutination inhibition (HAI) and neutralizing (Neut) antibody (Ab) titers were measured before and 8 and 21 days after each dose. Memory B-cell (MBC) responses were assessed. Results Vaccine was well tolerated. A total of 40% of subjects had an HAI Ab titer of ≥40 before vaccination. Eight-seven percent (95% confidence interval [CI], 79%–93%) and 73% (95% CI, 63%–81%) of subjects 18–64 years old (98 subjects) and ≥65 years old (90 subjects), respectively, had an HAI titer of ≥40 21 days after dose 1 (P = .01); 51% (95% CI, 41%–61%) and 52% (95% CI, 41%–62%) of younger and older subjects, respectively, developed ≥4-fold rises in titer (P = not significant). Neut Ab response patterns were similar. Geometric mean titers were higher in younger subjects. Dose 2 provided no significant enhancement in responses. Cross-reactive MBCs were detected before vaccination and expanded after vaccination. Preexisting H3N2v-specific MBCs positively correlated with early increases in vaccine-induced Ab. Conclusions In most healthy adults, one 15-µg dose of vaccine elicited levels of HAI Abs associated with protection. Studies in children and elderly individuals are indicated to define the immunization needs of these groups. Clinical Trials Registration NCT01746082. PMID:25649171

  3. Structure of the main oligomannoside chains of the hemagglutinin of the influenza virus A/Leningrad/385/80/ (H3N2)

    SciTech Connect

    Arbatskii, N.P.; Shashkov, A.S.; Zheltova, A.O.; Yurtov, D.V.; Derevitskaya, V.A.; Kochetkov, N.K.

    1986-09-01

    The structure of the four main oligomannoside carbohydrate chains from the hemagglutinin of the influenza virus A/Leningrad/385/80 (H3N2) have been established with the aid of /sup 1/H NMR spectroscopy. On the basis of the results obtained, the hypothesis has been put forward that the splitting out by ..cap alpha..-mannosidase I of four ..cap alpha..-1- ..-->.. 2-bound mannose residues in the transformation of the oligomannoside chain into a complex one is the limiting and selective stage of the processing of the carbohydrate chains in the biosynthesis of glycoproteins.

  4. Mutations acquired during cell culture isolation may affect antigenic characterisation of influenza A(H3N2) clade 3C.2a viruses.

    PubMed

    Skowronski, Danuta M; Sabaiduc, Suzana; Chambers, Catharine; Eshaghi, Alireza; Gubbay, Jonathan B; Krajden, Mel; Drews, Steven J; Martineau, Christine; De Serres, Gaston; Dickinson, James A; Winter, Anne-Luise; Bastien, Nathalie; Li, Yan

    2016-01-01

    As elsewhere, few (< 15%) sentinel influenza A(H3N2) clade 3C.2a viruses that dominated in Canada during the 2014/15 season could be antigenically characterised by haemagglutination inhibition (HI) assay. Clade 3C.2a viruses that could be HI-characterised had acquired genetic mutations during in vitro cell culture isolation that modified the potential glycosylation motif found in original patient specimens and the consensus sequence of circulating viruses at amino acid positions 158-160 of the haemagglutinin protein. Caution is warranted in extrapolating antigenic relatedness based on limited HI findings for clade 3C.2a viruses that continue to circulate globally.

  5. Optimization of an enzyme-linked lectin assay suitable for rapid antigenic characterization of the neuraminidase of human influenza A(H3N2) viruses

    PubMed Central

    Westgeest, Kim; Bestebroer, Theo M.; Spronken, Monique I.J.; Gao, Jin; Couzens, Laura; Osterhaus, Albert D.M.E.; Eichelberger, Maryna; Fouchier, Ron A.M.; de Graaf, Miranda

    2015-01-01

    Antibodies to neuraminidase (NA), the second most abundant surface protein of the influenza virus, contribute to protection against influenza virus infection. Although traditional and miniaturized thiobarbituric acid (TBA) neuraminidase inhibition (NI) assays have been successfully used to characterize the antigenic properties of NA, these methods are cumbersome and not easily amendable to rapid screening. An additional difficulty of the NI assay is the interference by hemagglutinin (HA)-specific antibodies. To prevent interference of HA-specific antibodies, most NI assays are performed with recombinant viruses containing a mismatched HA. However, generation of these viruses is time consuming and unsuitable for large-scale surveillance. The feasibility of using the recently developed enzyme-linked lectin assay (ELLA) to evaluate the antigenic relatedness of NA of wild type A(H3N2) viruses was assessed. Rather than using recombinant viruses, wild type A(H3N2) viruses were used as antigen with ferret sera elicited against recombinant viruses with a mismatched HA. In this study, details of the critical steps that are needed to modify and optimize the NI ELLA in a format that is reproducible, highly sensitive, and useful for influenza virus surveillance to monitor antigenic drift of NA are provided. PMID:25712563

  6. Optimization of an enzyme-linked lectin assay suitable for rapid antigenic characterization of the neuraminidase of human influenza A(H3N2) viruses.

    PubMed

    Westgeest, Kim B; Bestebroer, Theo M; Spronken, Monique I J; Gao, Jin; Couzens, Laura; Osterhaus, Albert D M E; Eichelberger, Maryna; Fouchier, Ron A M; de Graaf, Miranda

    2015-06-01

    Antibodies to neuraminidase (NA), the second most abundant surface protein of the influenza virus, contribute to protection against influenza virus infection. Although traditional and miniaturized thiobarbituric acid (TBA) neuraminidase inhibition (NI) assays have been successfully used to characterize the antigenic properties of NA, these methods are cumbersome and not easily amendable to rapid screening. An additional difficulty of the NI assay is the interference by hemagglutinin (HA)-specific antibodies. To prevent interference of HA-specific antibodies, most NI assays are performed with recombinant viruses containing a mismatched HA. However, generation of these viruses is time consuming and unsuitable for large-scale surveillance. The feasibility of using the recently developed enzyme-linked lectin assay (ELLA) to evaluate the antigenic relatedness of NA of wild type A(H3N2) viruses was assessed. Rather than using recombinant viruses, wild type A(H3N2) viruses were used as antigen with ferret sera elicited against recombinant viruses with a mismatched HA. In this study, details of the critical steps that are needed to modify and optimize the NI ELLA in a format that is reproducible, highly sensitive, and useful for influenza virus surveillance to monitor antigenic drift of NA are provided.

  7. Influenza evolution and H3N2 vaccine effectiveness, with application to the 2014/2015 season

    PubMed Central

    Li, Xi; Deem, Michael W.

    2016-01-01

    Influenza A is a serious disease that causes significant morbidity and mortality, and vaccines against the seasonal influenza disease are of variable effectiveness. In this article, we discuss the use of the pepitope method to predict the dominant influenza strain and the expected vaccine effectiveness in the coming flu season. We illustrate how the effectiveness of the 2014/2015 A/Texas/50/2012 [clade 3C.1] vaccine against the A/California/02/2014 [clade 3C.3a] strain that emerged in the population can be estimated via pepitope. In addition, we show by a multidimensional scaling analysis of data collected through 2014, the emergence of a new A/New Mexico/11/2014-like cluster [clade 3C.2a] that is immunologically distinct from the A/California/02/2014-like strains. PMID:27313229

  8. Immunogenicity and protective efficacy of recombinant fusion proteins containing spike protein of infectious bronchitis virus and hemagglutinin of H3N2 influenza virus in chickens.

    PubMed

    Yin, Lijuan; Zeng, Yuyao; Wang, Wei; Wei, Ying; Xue, Chunyi; Cao, Yongchang

    2016-09-01

    Infectious bronchitis (IB) is an acute and highly contagious viral respiratory disease of chickens and vaccination is the main method for disease control. The S1 protein, which contains several virus neutralization epitopes, is considered to be a target site of vaccine development. However, although protective immune responses could be induced by recombinant S1 protein, the protection rate in chickens was still low (<50%). Here, we generated fused S1 proteins with HA2 protein (rS1-HA2) or transmembrane domain and cytoplasmic tail (rS1-H3(TM)) from hemagglutinin of H3N2 influenza virus. After immunization, animals vaccinated with fusion proteins rS1-HA2 and rS1-H3(TM) demonstrated stronger robust humoral and cellular immune responses than that of rS1 and inactivated M41 vaccine. The protection rates of groups immunized with rS1-HA2 (87%) were significantly higher than the groups inoculated with rS1 (47%) and inactivated M41 vaccine (53%). And chickens injected with rS1-H3(TM) had similar level of protection (73%) comparing to chickens vaccinated with rS1 (47%) (P=0.07). Our data suggest that S1 protein fused to the HA2 or TM proteins from hemagglutinin of H3N2 influenza virus may provide a new strategy for high efficacy recombinant vaccine development against IBV. PMID:27497621

  9. Viral fusion efficacy of specific H3N2 influenza virus reassortant combinations at single-particle level

    PubMed Central

    Hsu, Hung-Lun; Millet, Jean K.; Costello, Deirdre A.; Whittaker, Gary R.; Daniel, Susan

    2016-01-01

    Virus pseudotyping is a useful and safe technique for studying entry of emerging strains of influenza virus. However, few studies have compared different reassortant combinations in pseudoparticle systems, or compared entry kinetics of native viruses and their pseudotyped analogs. Here, vesicular stomatitis virus (VSV)-based pseudovirions displaying distinct influenza virus envelope proteins were tested for fusion activity. We produced VSV pseudotypes containing the prototypical X-31 (H3) HA, either alone or with strain-matched or mismatched N2 NAs. We performed single-particle fusion assays using total internal reflection fluorescence microscopy to compare hemifusion kinetics among these pairings. Results illustrate that matching pseudoparticles behaved very similarly to native virus. Pseudoparticles harboring mismatched HA-NA pairings fuse at significantly slower rates than native virus, and NA-lacking pseudoparticles exhibiting the slowest fusion rates. Relative viral membrane HA density of matching pseudoparticles was higher than in mismatching or NA-lacking pseudoparticles. An equivalent trend of HA expression level on cell membranes of HA/NA co-transfected cells was observed and intracellular trafficking of HA was affected by NA co-expression. Overall, we show that specific influenza HA-NA combinations can profoundly affect the critical role played by HA during entry, which may factor into viral fitness and the emergence of new pandemic influenza viruses. PMID:27752100

  10. Influenza A viral loads in respiratory samples collected from patients infected with pandemic H1N1, seasonal H1N1 and H3N2 viruses

    PubMed Central

    2010-01-01

    Background Nasopharyngeal aspirate (NPA), nasal swab (NS), and throat swab (TS) are common specimens used for diagnosis of respiratory virus infections based on the detection of viral genomes, viral antigens and viral isolation. However, there is no documented data regarding the type of specimen that yields the best result of viral detection. In this study, quantitative real time RT-PCR specific for M gene was used to determine influenza A viral loads present in NS, NPA and TS samples collected from patients infected with the 2009 pandemic H1N1, seasonal H1N1 and H3N2 viruses. Various copy numbers of RNA transcripts derived from recombinant plasmids containing complete M gene insert of each virus strain were assayed by RT-PCR. A standard curve for viral RNA quantification was constructed by plotting each Ct value against the log quantity of each standard RNA copy number. Results Copy numbers of M gene were obtained through the extrapolation of Ct values of the test samples against the corresponding standard curve. Among a total of 29 patients with severe influenza enrolled in this study (12 cases of the 2009 pandemic influenza, 5 cases of seasonal H1N1 and 12 cases of seasonal H3N2 virus), NPA was found to contain significantly highest amount of viral loads and followed in order by NS and TS specimen. Viral loads among patients infected with those viruses were comparable regarding type of specimen analyzed. Conclusion Based on M gene copy numbers, we conclude that NPA is the best specimen for detection of influenza A viruses, and followed in order by NS and TS. PMID:20403211

  11. Sequence amplification via cell passaging creates spurious signals of positive adaptation in influenza virus H3N2 hemagglutinin

    PubMed Central

    McWhite, Claire D.; Meyer, Austin G.; Wilke, Claus O.

    2016-01-01

    Clinical influenza A virus isolates are frequently not sequenced directly. Instead, a majority of these isolates (~70% in 2015) are first subjected to passaging for amplification, most commonly in non-human cell culture. Here, we find that this passaging leaves distinct signals of adaptation, which can confound evolutionary analyses of the viral sequences. We find distinct patterns of adaptation to Madin-Darby (MDCK) and monkey cell culture absent from unpassaged hemagglutinin sequences. These patterns also dominate pooled datasets not separated by passaging type, and they increase in proportion to the number of passages performed. By contrast, MDCK-SIAT1 passaged sequences seem mostly (but not entirely) free of passaging adaptations. Contrary to previous studies, we find that using only internal branches of influenza virus phylogenetic trees is insufficient to correct for passaging artifacts. These artifacts can only be safely avoided by excluding passaged sequences entirely from subsequent analysis. We conclude that future influenza virus evolutionary analyses should appropriately control for potentially confounding effects of passaging adaptations. PMID:27713835

  12. Evolution of oseltamivir resistance mutations in Influenza A(H1N1) and A(H3N2) viruses during selection in experimentally infected mice.

    PubMed

    Pizzorno, Andrés; Abed, Yacine; Plante, Pier-Luc; Carbonneau, Julie; Baz, Mariana; Hamelin, Marie-Ève; Corbeil, Jacques; Boivin, Guy

    2014-11-01

    The evolution of oseltamivir resistance mutations during selection through serial passages in animals is still poorly described. Herein, we assessed the evolution of neuraminidase (NA) and hemagglutinin (HA) genes of influenza A/WSN/33 (H1N1) and A/Victoria/3/75 (H3N2) viruses recovered from the lungs of experimentally infected BALB/c mice receiving suboptimal doses (0.05 and 1 mg/kg of body weight/day) of oseltamivir over two generations. The traditional phenotypic and genotypic methods as well as deep-sequencing analysis were used to characterize the potential selection of mutations and population dynamics of oseltamivir-resistant variants. No oseltamivir-resistant NA or HA changes were detected in the recovered A/WSN/33 viruses. However, we observed a positive selection of the I222T NA substitution in the recovered A/Victoria/3/75 viruses, with a frequency increasing over time and with an oseltamivir concentration from 4% in the initial pretherapy inoculum up to 28% after two lung passages. Although the presence of mixed I222T viral populations in mouse lungs only led to a minimal increase in oseltamivir 50% enzyme-inhibitory concentrations (IC50s) (by a mean of 5.7-fold) compared to that of the baseline virus, the expressed recombinant A/Victoria/3/75 I222T NA protein displayed a 16-fold increase in the oseltamivir IC50 level compared to that of the recombinant wild type (WT). In conclusion, the combination of serial in vivo passages under neuraminidase inhibitor (NAI) pressure and temporal deep-sequencing analysis enabled, for the first time, the identification and selection of the oseltamivir-resistant I222T NA mutation in an influenza H3N2 virus. Additional in vivo selection experiments with other antivirals and drug combinations might provide important information on the evolution of antiviral resistance in influenza viruses.

  13. Incorporating structure context of HA protein to improve antigenicity calculation for influenza virus A/H3N2.

    PubMed

    Qiu, Jingxuan; Qiu, Tianyi; Yang, Yiyan; Wu, Dingfeng; Cao, Zhiwei

    2016-01-01

    The rapid and consistent mutation of influenza requires frequent evaluation of antigenicity variation among newly emerged strains, during which several in-silico methods have been reported to facilitate the assays. In this paper, we designed a structure-based antigenicity scoring model instead of those sequence-based previously published. Protein structural context was adopted to derive the antigenicity-dominant positions, as well as the physic-chemical change of local micro-environment in correlation with antigenicity change. Then a position specific scoring matrix (PSSM) profile and local environmental change over above positions were integrated to predict the antigenicity variance. Independent testing showed a high accuracy of 0.875, and sensitivity of 0.986, with a significant ability to discover antigenic-escaping strains. When applying this model to the historical data, global and regional antigenic drift events can be successfully detected. Furthermore, two well-known vaccine failure events were clearly suggested. Therefore, this structure-context model may be particularly useful to identify those to-be-failed vaccine strains, in addition to suggest potential new vaccine strains. PMID:27498613

  14. Incorporating structure context of HA protein to improve antigenicity calculation for influenza virus A/H3N2

    PubMed Central

    Qiu, Jingxuan; Qiu, Tianyi; Yang, Yiyan; Wu, Dingfeng; Cao, Zhiwei

    2016-01-01

    The rapid and consistent mutation of influenza requires frequent evaluation of antigenicity variation among newly emerged strains, during which several in-silico methods have been reported to facilitate the assays. In this paper, we designed a structure-based antigenicity scoring model instead of those sequence-based previously published. Protein structural context was adopted to derive the antigenicity-dominant positions, as well as the physic-chemical change of local micro-environment in correlation with antigenicity change. Then a position specific scoring matrix (PSSM) profile and local environmental change over above positions were integrated to predict the antigenicity variance. Independent testing showed a high accuracy of 0.875, and sensitivity of 0.986, with a significant ability to discover antigenic-escaping strains. When applying this model to the historical data, global and regional antigenic drift events can be successfully detected. Furthermore, two well-known vaccine failure events were clearly suggested. Therefore, this structure-context model may be particularly useful to identify those to-be-failed vaccine strains, in addition to suggest potential new vaccine strains. PMID:27498613

  15. The effects of a deleterious mutation load on patterns of influenza A/H3N2's antigenic evolution in humans

    PubMed Central

    Koelle, Katia; Rasmussen, David A

    2015-01-01

    Recent phylogenetic analyses indicate that RNA virus populations carry a significant deleterious mutation load. This mutation load has the potential to shape patterns of adaptive evolution via genetic linkage to beneficial mutations. Here, we examine the effect of deleterious mutations on patterns of influenza A subtype H3N2's antigenic evolution in humans. By first analyzing simple models of influenza that incorporate a mutation load, we show that deleterious mutations, as expected, act to slow the virus's rate of antigenic evolution, while making it more punctuated in nature. These models further predict three distinct molecular pathways by which antigenic cluster transitions occur, and we find phylogenetic patterns consistent with each of these pathways in influenza virus sequences. Simulations of a more complex phylodynamic model further indicate that antigenic mutations act in concert with deleterious mutations to reproduce influenza's spindly hemagglutinin phylogeny, co-circulation of antigenic variants, and high annual attack rates. DOI: http://dx.doi.org/10.7554/eLife.07361.001 PMID:26371556

  16. Paper-based enzyme-free immunoassay for rapid detection and subtyping of influenza A H1N1 and H3N2 viruses.

    PubMed

    Lei, Kin Fong; Huang, Chia-Hao; Kuo, Rei-Lin; Chang, Cheng-Kai; Chen, Kuan-Fu; Tsao, Kuo-Chien; Tsang, Ngan-Ming

    2015-07-01

    Development of rapid screening in the ambulatory environment is the most pressing needs for the control of spread of infectious disease. Despite there are many methods to detect the immunoassay results, quantitative measurement in rapid disease screening is still a great challenge for point-of-care applications. In this work, based on the internal structural protein, i.e., nucleoprotein (NP), and outer surface glycoproteins, i.e., H1 and H3, of the influenza viruses, specific and sensitive immunoassay on paper-based platform was evaluated and confirmed. Detection and subtyping of influenza A H1N1 and H3N2 viruses found in people were demonstrated by colorimetric paper-based sandwich immunoassay. Concentration-dependent response to influenza viruses was shown and the detection limits could achieve 2.7×10(3) pfu/assay for H1 detection and 2.7×10(4) pfu/assay for H3 detection, which are within the clinical relevant level. Moreover, detection of influenza virus from infected cell lysate and clinical samples was demonstrated to further confirm the reliability of the paper-based immunoassay. The use of paper for the development of diagnostic devices has the advantages of lightweight, ease-of-use, and low cost and paper-based immunoassay is appropriate to apply for rapid screening in point-of-care applications.

  17. LabDisk with complete reagent prestorage for sample-to-answer nucleic acid based detection of respiratory pathogens verified with influenza A H3N2 virus.

    PubMed

    Stumpf, F; Schwemmer, F; Hutzenlaub, T; Baumann, D; Strohmeier, O; Dingemanns, G; Simons, G; Sager, C; Plobner, L; von Stetten, F; Zengerle, R; Mark, D

    2016-01-01

    Portable point-of-care devices for pathogen detection require easy, minimal and user-friendly handling steps and need to have the same diagnostic performance compared to centralized laboratories. In this work we present a fully automated sample-to-answer detection of influenza A H3N2 virus in a centrifugal LabDisk with complete prestorage of reagents. Thus, the initial supply of the sample remains the only manual handling step. The self-contained LabDisk automates by centrifugal microfluidics all necessary process chains for PCR-based pathogen detection: pathogen lysis, magnetic bead based nucleic acid extraction, aliquoting of the eluate into 8 reaction cavities, and real-time reverse transcription polymerase chain reaction (RT-PCR). Prestored reagents comprise air dried specific primers and fluorescence probes, lyophilized RT-PCR mastermix and stick-packaged liquid reagents for nucleic acid extraction. Employing two different release frequencies for the stick-packaged liquid reagents enables on-demand release of highly wetting extraction buffers, such as sequential release of lysis and binding buffer. Microfluidic process-flow was successful in 54 out of 55 tested LabDisks. We demonstrate successful detection of the respiratory pathogen influenza A H3N2 virus in a total of 18 LabDisks with sample concentrations down to 2.39 × 10(4) viral RNA copies per ml, which is in the range of clinical relevance. Furthermore, we detected RNA bacteriophage MS2 acting as internal control in 3 LabDisks with a sample concentration down to 75 plaque forming units (pfu) per ml. All experiments were applied in a 2 kg portable, laptop controlled point-of-care device. The turnaround time of the complete analysis from sample-to-answer was less than 3.5 hours. PMID:26610171

  18. NS1 Protein Mutation I64T Affects Interferon Responses and Virulence of Circulating H3N2 Human Influenza A Viruses

    PubMed Central

    DeDiego, Marta L.; Nogales, Aitor; Lambert-Emo, Kris; Martinez-Sobrido, Luis

    2016-01-01

    ABSTRACT Influenza NS1 protein is the main viral protein counteracting host innate immune responses, allowing the virus to efficiently replicate in interferon (IFN)-competent systems. In this study, we analyzed NS1 protein variability within influenza A (IAV) H3N2 viruses infecting humans during the 2012-2013 season. We also evaluated the impact of the mutations on the ability of NS1 proteins to inhibit host innate immune responses and general gene expression. Surprisingly, a previously unidentified mutation in the double-stranded RNA (dsRNA)-binding domain (I64T) decreased NS1-mediated general inhibition of host protein synthesis by decreasing its interaction with cleavage and polyadenylation specificity factor 30 (CPSF30), leading to increased innate immune responses after viral infection. Notably, a recombinant A/Puerto Rico/8/34 H1N1 virus encoding the H3N2 NS1-T64 protein was highly attenuated in mice, most likely because of its ability to induce higher antiviral IFN responses at early times after infection and because this virus is highly sensitive to the IFN-induced antiviral state. Interestingly, using peripheral blood mononuclear cells (PBMCs) collected at the acute visit (2 to 3 days after infection), we show that the subject infected with the NS1-T64 attenuated virus has diminished responses to interferon and to interferon induction, suggesting why this subject could be infected with this highly IFN-sensitive virus. These data demonstrate the importance of influenza virus surveillance in identifying new mutations in the NS1 protein, affecting its ability to inhibit innate immune responses and, as a consequence, the pathogenicity of the virus. IMPORTANCE Influenza A and B viruses are one of the most common causes of respiratory infections in humans, causing 1 billion infections and between 300,000 and 500,000 deaths annually. Influenza virus surveillance to identify new mutations in the NS1 protein affecting innate immune responses and, as a consequence

  19. Genetic divergence of influenza A NS1 gene in pandemic 2009 H1N1 isolates with respect to H1N1 and H3N2 isolates from previous seasonal epidemics

    PubMed Central

    2010-01-01

    Background The Influenza A pandemic sustained by a new H1N1 variant (H1N1v) started in Mexico and the USA at the end of April 2009 spreading worldwide in a few weeks. In this study we investigate the variability of the NS1 gene of the pandemic H1N1v strain with respect to previous seasonal strains circulating in humans and the potential selection of virus variants through isolation in cell culture. Methods During the period April 27th 2009-Jan 15th 2010, 1633 potential 2009 H1N1v cases have been screened at our center using the CDC detection and typing realtime RT-PCR assays. Virus isolation on MDCK cells was systematically performed in 1/10 positive cases. A subset of 51 H1N1v strains isolated in the period May-September 2009 was selected for NS1 gene sequencing. In addition, 15 H1N1 and 47 H3N2 virus isolates from three previous seasonal epidemics (2006-2009) were analyzed in parallel. Results A low variability in the NS1 amino acid (aa) sequence among H1N1v isolates was shown (aa identity 99.5%). A slightly higher NS1 variability was observed among H1N1 and H3N2 strains from previous epidemics (aa identity 98.6% and 98.9%, respectively). The H1N1v strains were closely related (aa identity 92.1%) to swine reference strain (A/swine/Oklahoma/042169/2008). In contrast, substantial divergence (aa identity 83.4%) with respect to human reference strain A/Brevig Mission/1/1918 and previous epidemic strains H1N1 and H3N2 (aa identity 78.9% and 77.6%, respectively) was shown. Specific sequence signatures of uncertain significance in the new virus variant were a C-terminus deletion and a T215P substitution. Conclusions The H1N1v NS1 gene was more conserved than that of previous epidemic strains. In addition, a closer genetic identity of H1N1v with the swine than the human reference strains was shown. Hot-spots were shown in the H1N1v NS1 aa sequence whose biologic relevance remains to be investigated. PMID:20809948

  20. Human microRNAs profiling in response to influenza A viruses (subtypes pH1N1, H3N2, and H5N1)

    PubMed Central

    Makkoch, Jarika; Poomipak, Witthaya; Saengchoowong, Suthat; Khongnomnan, Kritsada; Praianantathavorn, Kesmanee; Jinato, Thananya; Poovorawan, Yong

    2016-01-01

    MicroRNAs (miRNAs) play an important role in regulation of gene silencing and are involved in many cellular processes including inhibition of infected viral replication. This study investigated cellular miRNA expression profiles operating in response to influenza virus in early stage of infection which might be useful for understanding and control of viral infection. A549 cells were infected with different subtypes of influenza virus (pH1N1, H3N2 and H5N1). After 24 h post-infection, miRNAs were extracted and then used for DNA library construction. All DNA libraries with different indexes were pooled together with equal concentration, followed by high-throughput sequencing based on MiSeq platform. The miRNAs were identified and counted from sequencing data by using MiSeq reporter software. The miRNAs expressions were classified into up and downregulated miRNAs compared to those found in non-infected cells. Mostly, each subtype of influenza A virus triggered the upregulated responses in miRNA expression profiles. Hsa-miR-101, hsa-miR-193b, hsa-miR-23b, and hsa-miR-30e* were upregulated when infected with all three subtypes of influenza A virus. Target prediction results showed that virus infection can trigger genes in cellular process, metabolic process, developmental process and biological regulation. This study provided some insights into the cellular miRNA profiling in response to various subtypes of influenza A viruses in circulation and which have caused outbreaks in human population. The regulated miRNAs might be involved in virus–host interaction or host defense mechanism, which should be investigated for effective antiviral therapeutic interventions. PMID:26518627

  1. H3N2 Mismatch of 2014-15 Northern Hemisphere Influenza Vaccines and Head-to-head Comparison between Human and Ferret Antisera derived Antigenic Maps.

    PubMed

    Xie, Hang; Wan, Xiu-Feng; Ye, Zhiping; Plant, Ewan P; Zhao, Yangqing; Xu, Yifei; Li, Xing; Finch, Courtney; Zhao, Nan; Kawano, Toshiaki; Zoueva, Olga; Chiang, Meng-Jung; Jing, Xianghong; Lin, Zhengshi; Zhang, Anding; Zhu, Yanhong

    2015-01-01

    The poor performance of 2014-15 Northern Hemisphere (NH) influenza vaccines was attributed to mismatched H3N2 component with circulating epidemic strains. Using human serum samples collected from 2009-10, 2010-11 and 2014-15 NH influenza vaccine trials, we assessed their cross-reactive hemagglutination inhibition (HAI) antibody responses against recent H3 epidemic isolates. All three populations (children, adults, and older adults) vaccinated with the 2014-15 NH egg- or cell-based vaccine, showed >50% reduction in HAI post-vaccination geometric mean titers against epidemic H3 isolates from those against egg-grown H3 vaccine strain A/Texas/50/2012 (TX/12e). The 2014-15 NH vaccines, regardless of production type, failed to further extend HAI cross-reactivity against H3 epidemic strains from previous seasonal vaccines. Head-to-head comparison between ferret and human antisera derived antigenic maps revealed different antigenic patterns among representative egg- and cell-grown H3 viruses characterized. Molecular modeling indicated that the mutations of epidemic H3 strains were mainly located in antibody-binding sites A and B as compared with TX/12e. To improve vaccine strain selection, human serologic testing on vaccination-induced cross-reactivity need be emphasized along with virus antigenic characterization by ferret model.

  2. H3N2 Mismatch of 2014-15 Northern Hemisphere Influenza Vaccines and Head-to-head Comparison between Human and Ferret Antisera derived Antigenic Maps

    NASA Astrophysics Data System (ADS)

    Xie, Hang; Wan, Xiu-Feng; Ye, Zhiping; Plant, Ewan P.; Zhao, Yangqing; Xu, Yifei; Li, Xing; Finch, Courtney; Zhao, Nan; Kawano, Toshiaki; Zoueva, Olga; Chiang, Meng-Jung; Jing, Xianghong; Lin, Zhengshi; Zhang, Anding; Zhu, Yanhong

    2015-10-01

    The poor performance of 2014-15 Northern Hemisphere (NH) influenza vaccines was attributed to mismatched H3N2 component with circulating epidemic strains. Using human serum samples collected from 2009-10, 2010-11 and 2014-15 NH influenza vaccine trials, we assessed their cross-reactive hemagglutination inhibition (HAI) antibody responses against recent H3 epidemic isolates. All three populations (children, adults, and older adults) vaccinated with the 2014-15 NH egg- or cell-based vaccine, showed >50% reduction in HAI post-vaccination geometric mean titers against epidemic H3 isolates from those against egg-grown H3 vaccine strain A/Texas/50/2012 (TX/12e). The 2014-15 NH vaccines, regardless of production type, failed to further extend HAI cross-reactivity against H3 epidemic strains from previous seasonal vaccines. Head-to-head comparison between ferret and human antisera derived antigenic maps revealed different antigenic patterns among representative egg- and cell-grown H3 viruses characterized. Molecular modeling indicated that the mutations of epidemic H3 strains were mainly located in antibody-binding sites A and B as compared with TX/12e. To improve vaccine strain selection, human serologic testing on vaccination-induced cross-reactivity need be emphasized along with virus antigenic characterization by ferret model.

  3. H3N2 Mismatch of 2014–15 Northern Hemisphere Influenza Vaccines and Head-to-head Comparison between Human and Ferret Antisera derived Antigenic Maps

    PubMed Central

    Xie, Hang; Wan, Xiu-Feng; Ye, Zhiping; Plant, Ewan P.; Zhao, Yangqing; Xu, Yifei; Li, Xing; Finch, Courtney; Zhao, Nan; Kawano, Toshiaki; Zoueva, Olga; Chiang, Meng-Jung; Jing, Xianghong; Lin, Zhengshi; Zhang, Anding; Zhu, Yanhong

    2015-01-01

    The poor performance of 2014–15 Northern Hemisphere (NH) influenza vaccines was attributed to mismatched H3N2 component with circulating epidemic strains. Using human serum samples collected from 2009–10, 2010–11 and 2014–15 NH influenza vaccine trials, we assessed their cross-reactive hemagglutination inhibition (HAI) antibody responses against recent H3 epidemic isolates. All three populations (children, adults, and older adults) vaccinated with the 2014–15 NH egg- or cell-based vaccine, showed >50% reduction in HAI post-vaccination geometric mean titers against epidemic H3 isolates from those against egg-grown H3 vaccine strain A/Texas/50/2012 (TX/12e). The 2014–15 NH vaccines, regardless of production type, failed to further extend HAI cross-reactivity against H3 epidemic strains from previous seasonal vaccines. Head-to-head comparison between ferret and human antisera derived antigenic maps revealed different antigenic patterns among representative egg- and cell-grown H3 viruses characterized. Molecular modeling indicated that the mutations of epidemic H3 strains were mainly located in antibody-binding sites A and B as compared with TX/12e. To improve vaccine strain selection, human serologic testing on vaccination-induced cross-reactivity need be emphasized along with virus antigenic characterization by ferret model. PMID:26472175

  4. H3N2 Mismatch of 2014-15 Northern Hemisphere Influenza Vaccines and Head-to-head Comparison between Human and Ferret Antisera derived Antigenic Maps.

    PubMed

    Xie, Hang; Wan, Xiu-Feng; Ye, Zhiping; Plant, Ewan P; Zhao, Yangqing; Xu, Yifei; Li, Xing; Finch, Courtney; Zhao, Nan; Kawano, Toshiaki; Zoueva, Olga; Chiang, Meng-Jung; Jing, Xianghong; Lin, Zhengshi; Zhang, Anding; Zhu, Yanhong

    2015-01-01

    The poor performance of 2014-15 Northern Hemisphere (NH) influenza vaccines was attributed to mismatched H3N2 component with circulating epidemic strains. Using human serum samples collected from 2009-10, 2010-11 and 2014-15 NH influenza vaccine trials, we assessed their cross-reactive hemagglutination inhibition (HAI) antibody responses against recent H3 epidemic isolates. All three populations (children, adults, and older adults) vaccinated with the 2014-15 NH egg- or cell-based vaccine, showed >50% reduction in HAI post-vaccination geometric mean titers against epidemic H3 isolates from those against egg-grown H3 vaccine strain A/Texas/50/2012 (TX/12e). The 2014-15 NH vaccines, regardless of production type, failed to further extend HAI cross-reactivity against H3 epidemic strains from previous seasonal vaccines. Head-to-head comparison between ferret and human antisera derived antigenic maps revealed different antigenic patterns among representative egg- and cell-grown H3 viruses characterized. Molecular modeling indicated that the mutations of epidemic H3 strains were mainly located in antibody-binding sites A and B as compared with TX/12e. To improve vaccine strain selection, human serologic testing on vaccination-induced cross-reactivity need be emphasized along with virus antigenic characterization by ferret model. PMID:26472175

  5. Genome-Wide Analysis of Evolutionary Markers of Human Influenza A(H1N1)pdm09 and A(H3N2) Viruses May Guide Selection of Vaccine Strain Candidates

    PubMed Central

    Belanov, Sergei S.; Bychkov, Dmitrii; Benner, Christian; Ripatti, Samuli; Ojala, Teija; Kankainen, Matti; Kai Lee, Hong; Wei-Tze Tang, Julian; Kainov, Denis E.

    2015-01-01

    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. PMID:26615216

  6. 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.

  7. Antigenic and genetic variation in the hemagglutinins of H1N1 and H3N2 human influenza a viruses in the Shanghai area from 2005 to 2008.

    PubMed

    Ren, Xiao-wei; Ju, Li-wen; Yang, Ji-xing; Lv, Xi-hong; Jiang, Lu-fang; Zhao, Nai-qing; Jiang, Qing-wu

    2011-07-01

    Continued rapid evolution of the influenza A virus is responsible for annual epidemics and occasional pandemics in the Shanghai area. In the present study, the representative strains of A/H1N1 and A/H3N2 influenza viruses isolated in the Shanghai area from 2005 to 2008 were antigenically and genetically characterized. The antigenic cartography method was carried out to visualize the hemagglutination-inhibition data. Antigenic differences were detected between circulating A/H1N1 strains isolated from 2005 to 2006 and the epidemic A/H1N1 strains isolated in 2008, which were found to be associated with the amino acid substitution K140E in HA1. The present vaccine strain A/Brisbane/59/2007 is considered to be capable of providing sufficient immunity against most of the circulating A/H1N1 viruses isolated in 2008 from the Shanghai population. The study showed that there were significant antigenic differences between the epidemic A/H3N2 strains isolated in 2007 and 2008, suggesting that antigenic drift had occurred in the A/H3N2 strains isolated in 2008. The P194L mutation was thought to be responsible for the antigenic evolution of influenza A/H3N2 viruses isolated from Shanghai in 2008. Evidence of antigenic drift suggests that the influenza A/H3N2 vaccine component needs to be updated.

  8. Pregnancy outcome and clinical status of gilts following experimental infection by H1N2, H3N2 and H1N1pdm09 influenza A viruses during the last month of gestation.

    PubMed

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

    2015-10-01

    The present study was planned to study the effect of various subtypes of swine influenza virus (SIV) circulating among pigs (H1N2, H3N2 and emerging pandemic strain of H1N1 influenza A virus (H1N1pdm09) on the course of pregnancy in naïve gilts experimentally infected during the last month of pregnancy. In addition, the clinical course of infection, distribution of viruses in various tissues (blood, placenta, fetal lung), and selected immunological, reproductive and productive parameters were also investigated. All SIV-inoculated gilts became infected. No abortions, stillbirths, intrauterine deaths or mummified fetuses were observed. No clinical signs of influenza virus infection or other disorders were observed in piglets born from infected and control gilts. There was a significant decrease in the number and frequency of lymphocytes in gilts inoculated with all influenza viruses. In general, the concentrations of IL-6, IL-10 and TNF-α were significantly higher in SIV-inoculated gilts as than in control animals, while IL-4 and IFN-γ were not detected in plasma at any time post-inoculation in SIV- or mock-inoculated gilts. No evidence for transplacental transmission of SIV was found. Viremia was also not observed in any of the infected females. On the basis of recent results, we hypothesize that pregnancy failure observed during SIV infection under field conditions is probably related to high fever and pro-inflammatory cytokines rather than a direct effect of the virus on the placenta, embryo or fetus.

  9. Molecular and antigenic characterization of the H3 hemagglutinin of H3N2 influenza A virus strains collected in the Czech Republic during the 2014/2015 epidemic season.

    PubMed

    Nagy, A; Jiřincová, H; Kynčl, J; Havlíčková, M

    2016-01-01

    The 2014/2015 influenza epidemic season was characterized by the predominance of the H3N2 subtype. The presented study investigated the genetic and antigenic heterogeneity of the H3N2 strains collected in the Czech Republic from November 2014 to March 2015. Phylogenetic analysis of the representative H3 hemagglutinin sequences was performed and the glycosylation status and crucial antigenic mutations were compared relative to the 2014 and 2015 vaccine strains (A/Texas/50/2012 and A/Switzerland/9715293/2013) and visualized in the H3 crystal structure. The molecular data were further supplemented by hemagglutination-inhibition test (HIT) results on fifteen H3N2 2014/2015 strains by using the A/Texas/50/2012 (H3N2) and A/Switzerland/9715293/13 (H3N2) antisera. Our data on the Czech H3N2 viruses from the 2014/2015 epidemic season could supplement the reports of official authorities with data from a particular geographi-cal area. PMID:27467326

  10. Host cell-mediated selection of influenza A (H3N2) virus variant subpopulations: lack of association between antigenic and receptor-binding properties.

    PubMed Central

    Pyhälä, R.; Pyhälä, L.; Pekkala, P.

    1988-01-01

    During the outbreak of influenza due to A (H3N3) viruses in Finland in 1985/6 virus pairs were isolated from the same clinical specimens in embryonated hens' eggs (CE) and in canine kidney cell cultures (MDCK). Some of these isolates, the E and M pairs, were distinguished by their reactions in haemagglutination inhibition (HI) tests carried out using polyclonal antisera, and by receptor-binding properties, as evidenced by differences in their elution activity from erythrocytes. Passage of the E- and M-virus isolates in the foreign host affected their serological characteristics, but the E virus did not convert to an M-like virus and the M virus did not convert to an E-like virus. Returning the viruses to grow in the host used for their isolation changed the serological reactions so that they were once more close to the reactions of the original isolates. This contrasts with the changes in receptor-binding properties. Rapid elution from hen erythrocytes, which has been described as a property of viruses binding to the SA alpha 2,3Gal sequence in preference to SA alpha 2,6Gal, characterized the virus passages grown solely in MDCK cell cultures. Cultivation of the M virus in CE, at any stage of its passage history, made the virus irreversibly incapable of elution. The M virus was more sensitive than the E virus to HI antibodies against heterologous viruses of the H3N2 subtype, and, when used as an antigen in HI serology, it more frequently (90% vs. 69%; P less than 0.01) detected diagnostic antibody responses in patients infected with viruses of this subtype in 1985/6. Use of antigens with a different passage history in HI serology provided evidence that this superiority, which may be due to the ability of the virus to pick out anamnestic antibody responses, is unrelated to the receptor-binding peculiarity of the M virus under consideration. The results support the concept that the host cell can select a diversity of virus variant subpopulations from a single clinical

  11. Enhanced Pneumonia With Pandemic 2009 A/H1N1 Swine Influenza Virus in Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. Swine influenza A viruses (SIV) in the major swine producing regions of North America consist of multiple subtypes of endemic H1N1, H1N2, and H3N2 derived from swine, avian and human influenza viruses with a triple reassortant internal gene (TRIG) constellation (1). Genetic drift and r...

  12. Moderate influenza vaccine effectiveness against hospitalisation with A(H3N2) and A(H1N1) influenza in 2013-14: Results from the InNHOVE network.

    PubMed

    Rondy, M; Castilla, J; Launay, O; Costanzo, S; Ezpeleta, C; Galtier, F; de Gaetano Donati, K; Moren, A

    2016-05-01

    We conducted a multicentre test negative case control study to estimate the 2013-14 influenza vaccine effectiveness (IVE) against hospitalised laboratory confirmed influenza in 12 hospitals in France, Italy and Spain. We included all ≥18 years hospitalised patients targeted by local influenza vaccination campaign reporting an influenza-like illness within 7 days before admission. We defined as cases patients RT-PCR positive for influenza and as controls those negative for all influenza virus. We used a logistic regression to calculate IVE adjusted for country, month of onset, chronic diseases and age. We included 104 A(H1N1)pdm09, 157 A(H3N2) cases and 585 controls. The adjusted IVE was 42.8% (95%CI: 6.3;65;0) against A(H1N1)pdm09. It was respectively 61.4% (95%CI: -1.9;85.4), 39.4% (95%CI: -32.2;72.2) and 19.7% (95%CI:-148.1;74.0) among patients aged 18-64, 65-79 and ≥80 years. The adjusted IVE against A(H3N2) was 38.1% (95%CI: 8.3;58.2) overall. It was respectively 7.8% (95%CI: -145.3;65.4), 25.6% (95%CI: -36.0;59.2) and 55.2% (95%CI: 15.4;76.3) among patients aged 18-64, 65-79 and ≥80 years. These results suggest a moderate and age varying effectiveness of the 2013-14 influenza vaccine to prevent hospitalised laboratory-confirmed influenza. While vaccination remains the most effective prevention measure, developing more immunogenic influenza vaccines is needed to prevent severe outcomes among target groups. PMID:27065000

  13. Moderate influenza vaccine effectiveness against hospitalisation with A(H3N2) and A(H1N1) influenza in 2013-14: Results from the InNHOVE network.

    PubMed

    Rondy, M; Castilla, J; Launay, O; Costanzo, S; Ezpeleta, C; Galtier, F; de Gaetano Donati, K; Moren, A

    2016-05-01

    We conducted a multicentre test negative case control study to estimate the 2013-14 influenza vaccine effectiveness (IVE) against hospitalised laboratory confirmed influenza in 12 hospitals in France, Italy and Spain. We included all ≥18 years hospitalised patients targeted by local influenza vaccination campaign reporting an influenza-like illness within 7 days before admission. We defined as cases patients RT-PCR positive for influenza and as controls those negative for all influenza virus. We used a logistic regression to calculate IVE adjusted for country, month of onset, chronic diseases and age. We included 104 A(H1N1)pdm09, 157 A(H3N2) cases and 585 controls. The adjusted IVE was 42.8% (95%CI: 6.3;65;0) against A(H1N1)pdm09. It was respectively 61.4% (95%CI: -1.9;85.4), 39.4% (95%CI: -32.2;72.2) and 19.7% (95%CI:-148.1;74.0) among patients aged 18-64, 65-79 and ≥80 years. The adjusted IVE against A(H3N2) was 38.1% (95%CI: 8.3;58.2) overall. It was respectively 7.8% (95%CI: -145.3;65.4), 25.6% (95%CI: -36.0;59.2) and 55.2% (95%CI: 15.4;76.3) among patients aged 18-64, 65-79 and ≥80 years. These results suggest a moderate and age varying effectiveness of the 2013-14 influenza vaccine to prevent hospitalised laboratory-confirmed influenza. While vaccination remains the most effective prevention measure, developing more immunogenic influenza vaccines is needed to prevent severe outcomes among target groups.

  14. Vaccination with 2014-15 Seasonal Inactivated Influenza Vaccine Elicits Cross-Reactive Anti-HA Antibodies with Strong ADCC Against Antigenically Drifted Circulating H3N2 Virus in Humans.

    PubMed

    Zhong, Weimin; Gross, F Liaini; Holiday, Crystal; Jefferson, Stacie N; Bai, Yaohui; Liu, Feng; Katz, Jacqueline M; Levine, Min Z

    2016-05-01

    It is well established that virus neutralizing (VN) antibodies to hemagglutinin (HA) antigens of influenza A viruses provide optimal protection against antigenically matched strains of influenza A viruses. In contrast, little is known about the potential role of HA-specific, non-neutralizing antibodies in protection against human influenza illness at present. In this study, we show that individuals vaccinated with the 2014-15 seasonal inactivated influenza vaccine displayed strong A/H3N2 HA-specific antibody-dependent cell-mediated cytotoxicity (ADCC) activities against an antigenically drifted H3N2 virus, despite poor induction of cross-reactive neutralizing antibodies against the antigenic variant. Given that passive transfer of influenza HA-monospecific immune sera with negligible levels of HA-specific VN antibodies can often confer considerable cross protection against lethal challenge with heterologous influenza viruses in animal models, it is conceivable that HA-specific, non-neutralizing antibodies may provide certain degree of cross protection against antigenically drifted influenza A viruses through ADCC in case of influenza vaccine mismatches. This may have important implications for public health. PMID:26950058

  15. 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

  16. [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.

  17. Influenza A H3N2 subtype virus NS1 protein targets into the nucleus and binds primarily via its C-terminal NLS2/NoLS to nucleolin and fibrillarin

    PubMed Central

    2012-01-01

    Background Influenza A virus non-structural protein 1 (NS1) is a virulence factor, which is targeted into the cell cytoplasm, nucleus and nucleolus. NS1 is a multi-functional protein that inhibits host cell pre-mRNA processing and counteracts host cell antiviral responses. Previously, we have shown that the NS1 protein of the H3N2 subtype influenza viruses possesses a C-terminal nuclear localization signal (NLS) that also functions as a nucleolar localization signal (NoLS) and targets the protein into the nucleolus. Results Here, we show that the NS1 protein of the human H3N2 virus subtype interacts in vitro primarily via its C-terminal NLS2/NoLS and to a minor extent via its N-terminal NLS1 with the nucleolar proteins, nucleolin and fibrillarin. Using chimeric green fluorescence protein (GFP)-NS1 fusion constructs, we show that the nucleolar retention of the NS1 protein is determined by its C-terminal NLS2/NoLS in vivo. Confocal laser microscopy analysis shows that the NS1 protein colocalizes with nucleolin in nucleoplasm and nucleolus and with B23 and fibrillarin in the nucleolus of influenza A/Udorn/72 virus-infected A549 cells. Since some viral proteins contain NoLSs, it is likely that viruses have evolved specific nucleolar functions. Conclusion NS1 protein of the human H3N2 virus interacts primarily via the C-terminal NLS2/NoLS and to a minor extent via the N-terminal NLS1 with the main nucleolar proteins, nucleolin, B23 and fibrillarin. PMID:22909121

  18. Newly emerging mutations in the matrix genes of the human influenza A(H1N1)pdm09 and A(H3N2) viruses reduce the detection sensitivity of real-time reverse transcription-PCR.

    PubMed

    Yang, Ji-Rong; Kuo, Chuan-Yi; Huang, Hsiang-Yi; Wu, Fu-Ting; Huang, Yi-Lung; Cheng, Chieh-Yu; Su, Yu-Ting; Chang, Feng-Yee; Wu, Ho-Sheng; Liu, Ming-Tsan

    2014-01-01

    New variants of the influenza A(H1N1)pdm09 and A(H3N2) viruses were detected in Taiwan between 2012 and 2013. Some of these variants were not detected in clinical specimens using a common real-time reverse transcription-PCR (RT-PCR) assay that targeted the conserved regions of the viral matrix (M) genes. An analysis of the M gene sequences of the new variants revealed that several newly emerging mutations were located in the regions where the primers or probes of the real-time RT-PCR assay bind; these included three mutations (G225A, T228C, and G238A) in the A(H1N1)pdm09 virus, as well as one mutation (C163T) in the A(H3N2) virus. These accumulated mismatch mutations, together with the previously identified C154T mutation of the A(H1N1)pdm09 virus and the C153T and G189T mutations of the A(H3N2) virus, result in a reduced detection sensitivity for the real-time RT-PCR assay. To overcome the loss of assay sensitivity due to mismatch mutations, we established a real-time RT-PCR assay using degenerate nucleotide bases in both the primers and probe and successfully increased the sensitivity of the assay to detect circulating variants of the human influenza A viruses. Our observations highlight the importance of the simultaneous use of different gene-targeting real-time RT-PCR assays for the clinical diagnosis of influenza.

  19. 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.

  20. International Laboratory Comparison of Influenza Microneutralization Assays for A(H1N1)pdm09, A(H3N2), and A(H5N1) Influenza Viruses by CONSISE.

    PubMed

    Laurie, Karen L; Engelhardt, Othmar G; Wood, John; Heath, Alan; Katz, Jacqueline M; Peiris, Malik; Hoschler, Katja; Hungnes, Olav; Zhang, Wenqing; Van Kerkhove, Maria D

    2015-08-01

    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.

  1. Swine Influenza (Swine Flu) in Pigs

    MedlinePlus

    ... in the United States since 2005 Prevention Treatment Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... Submit Button Past Newsletters Key Facts about Swine Influenza (Swine Flu) in Pigs Language: English Español ...

  2. Influenza exposure in United States feral swine populations

    USGS Publications Warehouse

    Hall, J.S.; Minnis, R.B.; Campbell, T.A.; Barras, S.; DeYoung, R.W.; Pabilonia, K.; Avery, M.L.; Sullivan, H.; Clark, L.; McLean, R.G.

    2008-01-01

    Swine play an important role in the disease ecology of influenza. Having cellular receptors in common with birds and humans, swine provide opportunities for mixed infections and potential for genetic reassortment between avian, human, and porcine influenza. Feral swine populations are rapidly expanding in both numbers and range and are increasingly coming into contact with waterfowl, humans, and agricultural operations. In this study, over 875 feral swine were sampled from six states across the United States for serologic evidence of exposure to influenza. In Oklahoma, Florida, and Missouri, USA, no seropositive feral swine were detected. Seropositive swine were detected in California, Mississippi, and Texas, USA. Antibody prevalences in these states were 1% in Mississippi, 5% in California, and 14.4% in Texas. All seropositive swine were exposed to H3N2 subtype, the predominant subtype currently circulating in domestic swine. The only exceptions were in San Saba County, Texas, where of the 15 seropositive samples, four were positive for H1N1 and seven for both H1N1 and H3N2. In Texas, there was large geographical and temporal variation in antibody prevalence and no obvious connection to domestic swine operations. No evidence of exposure to avian influenza in feral swine was uncovered. From these results it is apparent that influenza in feral swine poses a risk primarily to swine production operations. However, because feral swine share habitat with waterfowl, prey on and scavenge dead and dying birds, are highly mobile, and are increasingly coming into contact with humans, the potential for these animals to become infected with avian or human influenza in addition to swine influenza is a distinct possibility. ?? Wildlife Disease Association 2008.

  3. Effects of different adjuvants in the context of intramuscular and intranasal routes on humoral and cellular immune responses induced by detergent-split A/H3N2 influenza vaccines in mice.

    PubMed

    Baz, Mariana; Samant, Mukesh; Zekki, Hakima; Tribout-Jover, Pascale; Plante, Martin; Lanteigne, Anne-Marie; Hamelin, Marie-Eve; Mallett, Corey; Papadopoulou, Barbara; Boivin, Guy

    2012-02-01

    Influenza A/H3N2 viruses have caused the most severe epidemics since 1968 despite current immunization programs with inactivated vaccines. We undertook a side-by-side preclinical evaluation of different adjuvants (Alum, AS03, and Protollin) and routes of administration (intramuscular [i.m.] and intranasal [i.n.]) for assessing their effect on the immunogenicity and cross-reactivity of inactivated split vaccines (A/H3N2/New York/55/2004). Humoral and T cell-mediated immune responses against the homologous virus and a heterologous drifted strain (A/H3N2/Wisconsin/67/2005) were measured in BALB/c mice at 2, 6, and 19 weeks postboost. The AS03- and Alum-adjuvanted i.m. vaccines induced at least an 8-fold increase over the nonadjuvanted vaccine in functional antibody titers against both the homotypic and heterotypic strains and low IgG2a and high IgG1 levels, suggesting a mixed Th1/Th2 response with a Th2 trend. The Protollin-adjuvanted i.n. vaccine induced the lowest IgG1/IgG2a ratio, which is indicative of a mixed Th1/Th2-type profile with a Th1 trend. This adjuvanted vaccine was the only vaccine to stimulate a mucosal IgA response. Whatever the timing after the boost, both hemagglutination inhibition (HAI) and microneutralization (MN) titers were higher with the AS03-adjuvanted i.m. vaccine than with the protollin-adjuvanted i.n. vaccine. Finally, the Alum-adjuvanted i.m. vaccine and the lower-dose Protollin-adjuvanted i.n. vaccine elicited significantly higher CD4(+) Th1 and Th2 responses and more gamma interferon (IFN-γ)-producing CD8(+) T cells than the nonadjuvanted vaccine. Our data indicate that the adjuvanted vaccines tested in this study can elicit stronger, more persistent, and broader immune responses against A/H3N2 strains than nonadjuvanted inactivated influenza vaccines.

  4. Role of Preschool and Primary School Children in Epidemics of Influenza A in a Local Community in Japan during Two Consecutive Seasons with A(H3N2) as a Predominant Subtype.

    PubMed

    Mimura, Satoshi; Kamigaki, Taro; Takahashi, Yoshihiro; Umenai, Takamichi; Kudou, Mataka; Oshitani, Hitoshi

    2015-01-01

    Enhanced influenza surveillance was implemented to analyze transmission dynamics particularly driving force of influenza transmission in a community during 2011/12 and 2012/13 seasons in Odate City, Japan. In these two consecutive seasons, influenza A(H3N2) was the predominant influenza A subtype. Suspected influenza cases were tested by commercial rapid test kits. Demographic and epidemiological information of influenza positive cases were recorded using a standardized questionnaire, which included age or age group, date of visit, date of fever onset, and the result of rapid test kit. Epidemiological parameters including epidemic midpoint (EM) and growth rate (GR) were analyzed. In 2012/13 season, numbers of influenza A positive cases were significantly lower among preschool (212 cases) and primary school (224 cases) children than in 2011/12 season (461 and 538 cases, respectively). Simultaneously, total influenza A cases were also reduced from 2,092 in 2011/12 season to 1,846 in 2012/13 season. The EMs in preschool and primary school children were earlier than EMs for adult and all age group in both 2011/12 and 2012/13 seasons. The GR in 2012/13 season was significantly lower than that in 2011/12 season (0.11 and 0.18, respectively, p = 0.003). Multiple linear regression analysis by school districts revealed that GRs in both seasons were significantly correlated with the incidence of school age children. Our findings suggest that preschool and primary school children played an important role as a driving force of epidemics in the community in both 2011/12 and 2012/13 seasons. The reduction of total influenza A cases in 2012/13 season can be explained by decreased susceptible population in these age groups due to immunity acquired by infections in 2011/12 season. Further investigations are needed to investigate the effect of pre-existing immunity on influenza transmission in the community.

  5. Enhanced replication of avian-origin H3N2 canine influenza virus in eggs, cell cultures and mice by a two-amino acid insertion in neuraminidase stalk.

    PubMed

    Lin, Yan; Xie, Xing; Zhao, Yanbing; Kalhoro, Dildar Hussain; Lu, Chengping; Liu, Yongjie

    2016-01-01

    Canine influenza virus (CIV) is a newly identified, highly contagious respiratory pathogen in dogs. Recent studies indicate that avian-origin H3N2 CIV are circulating in Chinese dogs. To investigate the effects of a two-amino acid (2-aa) insertion naturally occurring at the distal end of the neuraminidase (NA) stalk found in Chinese isolates since 2010 on virus replication and virulence, we rescued the CIV strain, A/canine/Jiangsu/06/2011(H3N2) and its NA mutant without the 2-aa insertion using reverse genetics. The NA stalk length affected virus growth in cell culture. Compared to the short stalk strain (without 2-aa insertion), the long stalk strain (with 2-aa insertion) exhibited higher peak titers and greater yields in Madin-Darby canine kidney (MDCK) cells, chicken embryo fibroblasts and canine bronchiolar epithelial cells, as well as much larger plaques in MDCK cell monolayers. Furthermore, mice inoculated with the long stalk strain showed more severe pathologic damage in lung and higher proportion of detectable viral RNA in tissues. The long stalk strain induced local IFN-γ production with faster kinetics and higher levels in mice. However, in chickens, the two viral strains showed no significant difference with nearly the same proportion of detectable viral RNA loads in tissues. These observations suggest that the 2-aa insertion in the NA stalk acquired by avian-origin H3N2 CIV helps to enhance viral replication and is likely a result of adaptive evolution in canine hosts. PMID:27160077

  6. [A comparative study of the inoculation properties of live recombinant and inactivated influenza vaccines made from strain A/Philippines/2/82 (H3N2) in 8- to 15-year-old children].

    PubMed

    Slepushkin, A N; Obrosova-Serova, N P; Burtseva, E I; Govorkova, E A; Rudenko, L G; Vartanian, R V; Vereshchinskiĭ, A I; Musina, M D; Lonskaia, N I; Zazimko, L A

    1991-01-01

    This study was carried out to compare reactogenicity, immunogenicity, and efficacy of live attenuated and inactivated influenza vaccines prepared from influenza A/Philippines/2/82-like virus strains. Schoolchildren of a boarding school of Moscow were randomly divided into three groups: (1) vaccinated with a live attenuated vaccine, (2) vaccinated with inactivated influenza vaccine, and (3) given placebo. Both vaccines were well tolerated by the children, with practically no severe general or local reactions. The inactivated vaccine was found to be superior to the live one in its capacity to stimulate humoral immunity studied by HI, EIA, and microneutralization tests. In 69.7% of the children given the inactivated vaccine, seroconversion to the vaccine strain was detected by two or three methods of antibody titration used. Only 35.4% seroconversions were demonstrated in children immunized with the live influenza vaccine. Enzyme immunoassay was found to be a more sensitive but less specific method for antibody titration as compared with HI test whereas microneutralization proved to be more specific but less sensitive for titration of antibodies to influenza A (H3N2) viruses.

  7. An H1-H3 chimeric influenza virosome confers complete protection against lethal challenge with PR8 (H1N1) and X47 (H3N2) viruses in mice.

    PubMed

    Abdoli, Asghar; Soleimanjahi, Hoorieh; Tavassoti Kheiri, Masoumeh; Jamali, Abbas; Mazaheri, Vahideh; Abdollahpour Alitappeh, Meghdad

    2014-12-01

    Annual health threats and economic damages caused by influenza virus are still a main concern of the World Health Organization and other health departments all over the world. An influenza virosome is a highly efficient immunomodulating carrier mimicking the natural antigen presentation pathway and has shown an excellent tolerability profile due to its biocompatibility and purity. The major purpose of this study was to construct a new chimeric virosome influenza vaccine containing hemagglutinin (HA) and neuraminidase (NA) proteins derived from the A/PR/8/1934 (H1N1) (PR8) and A/X/47 (H3N2) (X47) viruses, and to evaluate its efficacy as a vaccine candidate in mice. A single intramuscular vaccination with the chimeric virosomes provided complete protection against lethal challenge with the PR8 and X47 viruses. The chimeric virosomes induced high IgG antibody responses as well as hemagglutination inhibition (HAI) titers. HAI titers following the chimeric virosome vaccination were at the same level as the whole inactivated influenza vaccine. Mice immunized with the chimeric virosomes displayed considerably less weight loss and exhibited significantly reduced viral load in their lungs compared with the controls. The chimeric virosomes can be used as an innovative vaccine formulation to confer protection against a broad range of influenza viruses. PMID:25066138

  8. An H1-H3 chimeric influenza virosome confers complete protection against lethal challenge with PR8 (H1N1) and X47 (H3N2) viruses in mice.

    PubMed

    Abdoli, Asghar; Soleimanjahi, Hoorieh; Tavassoti Kheiri, Masoumeh; Jamali, Abbas; Mazaheri, Vahideh; Abdollahpour Alitappeh, Meghdad

    2014-12-01

    Annual health threats and economic damages caused by influenza virus are still a main concern of the World Health Organization and other health departments all over the world. An influenza virosome is a highly efficient immunomodulating carrier mimicking the natural antigen presentation pathway and has shown an excellent tolerability profile due to its biocompatibility and purity. The major purpose of this study was to construct a new chimeric virosome influenza vaccine containing hemagglutinin (HA) and neuraminidase (NA) proteins derived from the A/PR/8/1934 (H1N1) (PR8) and A/X/47 (H3N2) (X47) viruses, and to evaluate its efficacy as a vaccine candidate in mice. A single intramuscular vaccination with the chimeric virosomes provided complete protection against lethal challenge with the PR8 and X47 viruses. The chimeric virosomes induced high IgG antibody responses as well as hemagglutination inhibition (HAI) titers. HAI titers following the chimeric virosome vaccination were at the same level as the whole inactivated influenza vaccine. Mice immunized with the chimeric virosomes displayed considerably less weight loss and exhibited significantly reduced viral load in their lungs compared with the controls. The chimeric virosomes can be used as an innovative vaccine formulation to confer protection against a broad range of influenza viruses.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. Improvement of influenza A/Fujian/411/02 (H3N2) virus growth in embryonated chicken eggs by balancing the hemagglutinin and neuraminidase activities, using reverse genetics.

    PubMed

    Lu, Bin; Zhou, Helen; Ye, Dan; Kemble, George; Jin, Hong

    2005-06-01

    The H3N2 influenza A/Fujian/411/02-like virus strains that circulated during the 2003-2004 influenza season caused influenza epidemics. Most of the A/Fujian/411/02 virus lineages did not replicate well in embryonated chicken eggs and had to be isolated originally by cell culture. The molecular basis for the poor replication of A/Fujian/411/02 virus was examined in this study by the reverse genetics technology. Two antigenically related strains that replicated well in embryonated chicken eggs, A/Sendai-H/F4962/02 and A/Wyoming/03/03, were compared with the prototype A/Fujian/411/02 virus. A/Sendai differed from A/Fujian by three amino acids in the neuraminidase (NA), whereas A/Wyoming differed from A/Fujian by five amino acids in the hemagglutinin (HA). The HA and NA segments of these three viruses were reassorted with cold-adapted A/Ann Arbor/6/60, the master donor virus for the live attenuated type A influenza vaccines (FluMist). The HA and NA residues differed between these three H3N2 viruses evaluated for their impact on virus replication in MDCK cells and in embryonated chicken eggs. It was determined that replication of A/Fujian/411/02 in eggs could be improved by either changing minimum of two HA residues (G186V and V226I) to increase the HA receptor-binding ability or by changing a minimum of two NA residues (E119Q and Q136K) to lower the NA enzymatic activity. Alternatively, recombinant A/Fujian/411/02 virus could be adapted to grow in eggs by two amino acid substitutions in the HA molecule (H183L and V226A), which also resulted in the increased HA receptor-binding activity. Thus, the balance between the HA and NA activities is critical for influenza virus replication in a different host system. The HA or NA changes that increased A/Fujian/411/02 virus replication in embryonated chicken eggs were found to have no significant impact on antigenicity of these recombinant viruses. This study demonstrated that the reverse genetics technology could be used to

  11. Full Genome Characterization of Human Influenza A/H3N2 Isolates from Asian Countries Reveals a Rare Amantadine Resistance-Conferring Mutation and Novel PB1-F2 Polymorphisms

    PubMed Central

    Zaraket, Hassan; Kondo, Hiroki; Hibino, Akinobu; Yagami, Ren; Odagiri, Takashi; Takemae, Nobuhiro; Tsunekuni, Ryota; Saito, Takehiko; Myint, Yi Yi; Kyaw, Yadanar; Oo, Khin Yi; Tin, Htay Htay; Lin, Nay; Anh, Nguyen Phuong; Hang, Nguyen Le Khanh; Mai, Le Quynh; Hassan, Mohd R.; Shobugawa, Yugo; Tang, Julian; Dbaibo, Ghassan; Saito, Reiko

    2016-01-01

    Influenza A viruses evolve at a high rate requiring continuous monitoring to maintain the efficacy of vaccines and antiviral drugs. We performed next generation sequencing analysis of 100 influenza A/H3N2 isolates collected in four Asian countries (Japan, Lebanon, Myanmar, and Vietnam) during 2012–2015. Phylogenetic analysis revealed several reassortment events leading to the circulation of multiple clades within the same season. This was particularly evident during the 2013 and 2013/2014 seasons. Importantly, our data showed that certain lineages appeared to be fitter and were able to persist into the following season. The majority of A/H3N2 viruses continued to harbor the M2-S31N mutation conferring amantadine-resistance. In addition, an S31D mutation in the M2-protein, conferring a similar level of resistance as the S31N mutation, was detected in three isolates obtained in Japan during the 2014/2015 season. None of the isolates possessed the NA-H274Y mutation conferring oseltamivir-resistance, though a few isolates were found to contain mutations at the catalytic residue 151 (D151A/G/N or V) of the NA protein. These variations did not alter the susceptibility to neuraminidase inhibitors and were not detected in the original clinical specimens, suggesting that they had been acquired during their passage in MDCK cells. Novel polymorphisms were detected in the PB1-F2 open-reading frame resulting in truncations in the protein of 24–34 aminoacids in length. Thus, this study has demonstrated the utility of monitoring the full genome of influenza viruses to allow the detection of the potentially fittest lineages. This enhances our ability to predict the strain(s) most likely to persist into the following seasons and predict the potential degree of vaccine match or mismatch with the seasonal influenza season for that year. This will enable the public health and clinical teams to prepare for any related healthcare burden, depending on whether the vaccine match is

  12. Full Genome Characterization of Human Influenza A/H3N2 Isolates from Asian Countries Reveals a Rare Amantadine Resistance-Conferring Mutation and Novel PB1-F2 Polymorphisms.

    PubMed

    Zaraket, Hassan; Kondo, Hiroki; Hibino, Akinobu; Yagami, Ren; Odagiri, Takashi; Takemae, Nobuhiro; Tsunekuni, Ryota; Saito, Takehiko; Myint, Yi Yi; Kyaw, Yadanar; Oo, Khin Yi; Tin, Htay Htay; Lin, Nay; Anh, Nguyen Phuong; Hang, Nguyen Le Khanh; Mai, Le Quynh; Hassan, Mohd R; Shobugawa, Yugo; Tang, Julian; Dbaibo, Ghassan; Saito, Reiko

    2016-01-01

    Influenza A viruses evolve at a high rate requiring continuous monitoring to maintain the efficacy of vaccines and antiviral drugs. We performed next generation sequencing analysis of 100 influenza A/H3N2 isolates collected in four Asian countries (Japan, Lebanon, Myanmar, and Vietnam) during 2012-2015. Phylogenetic analysis revealed several reassortment events leading to the circulation of multiple clades within the same season. This was particularly evident during the 2013 and 2013/2014 seasons. Importantly, our data showed that certain lineages appeared to be fitter and were able to persist into the following season. The majority of A/H3N2 viruses continued to harbor the M2-S31N mutation conferring amantadine-resistance. In addition, an S31D mutation in the M2-protein, conferring a similar level of resistance as the S31N mutation, was detected in three isolates obtained in Japan during the 2014/2015 season. None of the isolates possessed the NA-H274Y mutation conferring oseltamivir-resistance, though a few isolates were found to contain mutations at the catalytic residue 151 (D151A/G/N or V) of the NA protein. These variations did not alter the susceptibility to neuraminidase inhibitors and were not detected in the original clinical specimens, suggesting that they had been acquired during their passage in MDCK cells. Novel polymorphisms were detected in the PB1-F2 open-reading frame resulting in truncations in the protein of 24-34 aminoacids in length. Thus, this study has demonstrated the utility of monitoring the full genome of influenza viruses to allow the detection of the potentially fittest lineages. This enhances our ability to predict the strain(s) most likely to persist into the following seasons and predict the potential degree of vaccine match or mismatch with the seasonal influenza season for that year. This will enable the public health and clinical teams to prepare for any related healthcare burden, depending on whether the vaccine match is

  13. Full Genome Characterization of Human Influenza A/H3N2 Isolates from Asian Countries Reveals a Rare Amantadine Resistance-Conferring Mutation and Novel PB1-F2 Polymorphisms.

    PubMed

    Zaraket, Hassan; Kondo, Hiroki; Hibino, Akinobu; Yagami, Ren; Odagiri, Takashi; Takemae, Nobuhiro; Tsunekuni, Ryota; Saito, Takehiko; Myint, Yi Yi; Kyaw, Yadanar; Oo, Khin Yi; Tin, Htay Htay; Lin, Nay; Anh, Nguyen Phuong; Hang, Nguyen Le Khanh; Mai, Le Quynh; Hassan, Mohd R; Shobugawa, Yugo; Tang, Julian; Dbaibo, Ghassan; Saito, Reiko

    2016-01-01

    Influenza A viruses evolve at a high rate requiring continuous monitoring to maintain the efficacy of vaccines and antiviral drugs. We performed next generation sequencing analysis of 100 influenza A/H3N2 isolates collected in four Asian countries (Japan, Lebanon, Myanmar, and Vietnam) during 2012-2015. Phylogenetic analysis revealed several reassortment events leading to the circulation of multiple clades within the same season. This was particularly evident during the 2013 and 2013/2014 seasons. Importantly, our data showed that certain lineages appeared to be fitter and were able to persist into the following season. The majority of A/H3N2 viruses continued to harbor the M2-S31N mutation conferring amantadine-resistance. In addition, an S31D mutation in the M2-protein, conferring a similar level of resistance as the S31N mutation, was detected in three isolates obtained in Japan during the 2014/2015 season. None of the isolates possessed the NA-H274Y mutation conferring oseltamivir-resistance, though a few isolates were found to contain mutations at the catalytic residue 151 (D151A/G/N or V) of the NA protein. These variations did not alter the susceptibility to neuraminidase inhibitors and were not detected in the original clinical specimens, suggesting that they had been acquired during their passage in MDCK cells. Novel polymorphisms were detected in the PB1-F2 open-reading frame resulting in truncations in the protein of 24-34 aminoacids in length. Thus, this study has demonstrated the utility of monitoring the full genome of influenza viruses to allow the detection of the potentially fittest lineages. This enhances our ability to predict the strain(s) most likely to persist into the following seasons and predict the potential degree of vaccine match or mismatch with the seasonal influenza season for that year. This will enable the public health and clinical teams to prepare for any related healthcare burden, depending on whether the vaccine match is

  14. 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.

  15. Host microRNA molecular signatures associated with human H1N1 and H3N2 influenza A viruses reveal an unanticipated antiviral activity for miR-146a.

    PubMed

    Terrier, Olivier; Textoris, Julien; Carron, Coralie; Marcel, Virginie; Bourdon, Jean-Christophe; Rosa-Calatrava, Manuel

    2013-05-01

    While post-transcriptional regulation of gene expression by microRNAs (miRNAs) has been shown to be involved in influenza virus replication cycle, only a few studies have further investigated this aspect in a human cellular model infected with human influenza viruses. In this study, we performed miRNA global profiling in human lung epithelial cells (A549) infected by two different subtypes of human influenza A viruses (H1N1 and H3N2). We identified a common miRNA signature in response to infection by the two different strains, highlighting a pool of five miRNAs commonly deregulated, which are known to be involved in the innate immune response or apoptosis. Among the five miRNA hits, the only upregulated miRNA in response to influenza infection corresponded to miR-146a. Based on a previously published gene expression dataset, we extracted inversely correlated miR-146a target genes and determined their first-level interactants. This functional analysis revealed eight distinct biological processes strongly associated with these interactants: Toll-like receptor pathway, innate immune response, cytokine production and apoptosis. To better understand the biological significance of miR-146a upregulation, using a reporter assay and a specific anti-miR-146a inhibitor, we confirmed that infection increased the endogenous miR-146a promoter activity and that inhibition of miR-146a significantly increased viral propagation. Altogether, our results suggest a functional role of miR-146a in the outcome of influenza infection, at the crossroads of several biological processes. PMID:23343627

  16. 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. PMID:26196759

  17. 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

  18. 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.

  19. Swine origin influenza (swine flu).

    PubMed

    Sebastian, Meghna R; Lodha, Rakesh; Kabra, S K

    2009-08-01

    Swine origin influenza was first recognized in the border area of Mexico and United States in April 2009 and during a short span of two months became the first pandemic. The currently circulating strain of swine origin influenza virus of the H1N1 strain has undergone triple reassortment and contains genes from the avian, swine and human viruses. It is transmitted by droplets or fomites. Incubation period is 2 to 7 days. Common clinical symptoms are indistinguishable by any viral respiratory illness, and include fever, cough, sore throat and myalgia. A feature seen more frequently with swine origin influenza is GI upset. Less than 10% of patients require hospitalization. Patients at risk of developing severe disease are - younger than five years, elderly, pregnant women, with chronic systemic illnesses, adolescents on aspirin. Of the severe manifestations of swine origin influenza, pneumonia and respiratory failure are the most common. Unusual symptoms reported are conjunctivitis, parotitis, hemophagocytic syndrome. Infants may present with fever and lethargy with no respiratory symptoms. Diagnosis is based on RT PCR, Viral culture or increasing neutralizing antibodies. Principle of treatment consist of isolation, universal precautions, good infection control practices, supportive care and use of antiviral drugs. Antiviral drugs effective against H1N1 virus include: oseltamivir and zamanavir. With good supportive care case fatality is less than 1%. Preventive measures include: social distancing, practicing respiratory etiquette, hand hygiene and use of chemoprohylaxis with antiviral drugs. Vaccine against H1N1 is not available at present, but will be available in near future.

  20. Population susceptibility to North American and Eurasian swine influenza viruses in England, at three time points between 2004 and 2011.

    PubMed

    Hoschler, K; Thompson, C; Casas, I; Ellis, J; Galiano, M; Andrews, N; Zambon, M

    2013-01-01

    Age-stratified sera collected in 2004, 2008 and 2010 in England were evaluated for antibody to swine influenza A(H3N2) and A(H1N1) viruses from the United States or Europe as a measure of population susceptibility to the emergence of novel viruses. Children under 11 years of age had little or no measurable antibody to recent swine H3N2 viruses despite their high levels of antibody to recent H3N2 seasonal human strains. Adolescents and young adults (born 1968–1999) had higher antibody levels to swine H3N2 viruses. Antibody levels to swine H3N2 influenza show little correlation with exposure to recent seasonal H3N2 (A/Perth/16/2009) strains, but with antibody to older H3N2 strains represented by A/Wuhan/359/1995. Children had the highest seropositivity to influenza A(H1N1)pdm09 virus, and young adults had the lowest antibody levels to A/Perth/16/2009. No age group showed substantial antibody levels to A/Aragon/RR3218/2008, a European swine H1N1 virus belonging to the Eurasian lineage. After vaccination with contemporary trivalent vaccine we observed evidence of boosted reactivity to swine H3N2 viruses in children and adults, while only a limited boosting effect on antibody levels to A/Aragon/RR3218/2008 was observed in both groups. Overall, our results suggest that different vaccination strategies may be necessary according to age if swine viruses emerge as a significant pandemic threat.

  1. In Silico Identification of Highly Conserved Epitopes of Influenza A H1N1, H2N2, H3N2, and H5N1 with Diagnostic and Vaccination Potential.

    PubMed

    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.

  2. 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

  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. Swine influenza viruses: an Asian perspective.

    PubMed

    Choi, Young-Ki; Pascua, Phillippe Noriel Q; Song, Min-Suk

    2013-01-01

    Swine influenza viruses (SIVs) are respiratory viral pathogens of pigs that are capable of causing serious global public health concerns in human. Because of their dual susceptibility to mammalian and avian influenza A viruses, pigs are the leading intermediate hosts for genetic reassortment and interspecies transmission and serve as reservoirs of antigenically divergent human viruses from which zoonotic stains with pandemic potential may arise. Pandemic influenza viruses emerging after the 1918 Spanish flu have originated in asia. Although distinct lineages of North American and European SIVs of the H1N1, H3N2, and HiN2 subtypes have been widely studied, less is known about the porcine viruses that are circulating among pig populations throughout Asia. The current review understanding of Contemporary viruses, human infection with SIVs, and the potential threat of novel pandemic strains are described, Furthermore, to best use the limited resources that are available for comprehensive genetic assessment of influenza, consensus efforts among Asian nations to increase epidemiosurveillance of swine herds is also strongly promoted.

  5. Seroprevalence and risk factors of swine influenza in Spain.

    PubMed

    Simon-Grifé, M; Martín-Valls, G E; Vilar, M J; García-Bocanegra, I; Mora, M; Martín, M; Mateu, E; Casal, J

    2011-04-21

    Swine influenza is caused by type A influenza virus. Pigs can be infected by both avian and human influenza viruses; therefore, the influenza virus infection in pigs is considered an important public health concern. The aims of present study were to asses the seroprevalence of swine influenza subtypes in Spain and explore the risk factors associated with the spread of those infections. Serum samples from 2151 pigs of 98 randomly selected farms were analyzed by an indirect ELISA for detection of antibodies against nucleoprotein A of influenza viruses and by the hemagglutination inhibition (HI) using H1N1, H1N2 and H3N2 swine influenza viruses (SIV) as antigens. Data gathered in questionnaires filled for each farm were used to explore risk factors associated with swine influenza. For that purpose, data were analyzed using the generalized estimating equations method and, in parallel by means of a logistic regression. By ELISA, 92 farms (93.9%; CI(95%): 89.1-98.7%) had at least one positive animal and, in total, 1340/2151 animals (62.3%; CI(95%): 60.2-64.3%) were seropositive. A total of 1622 animals (75.4%; CI(95%): 73.6-77.2%) were positive in at least one of the HI tests. Of the 98 farms, 91 (92.9%; CI(95%): 87.7-98.1%) had H1N1 seropositive animals; 63 (64.3%; CI(95%): 54.6-73.9%) had H1N2 seropositive pigs and 91 (92.9%; CI(95%): 87.7-98.1%) were positive to H3N2. Mixed infections were detected in 88 farms (89.8; CI(95%): 83.7-95.9%). Three risk factors were associated with seroprevalences of SIV: increased replacement rates in pregnancy units and, for fatteners, existence of open partitions between pens and uncontrolled entrance to the farm.

  6. H3N2v and You

    MedlinePlus

    ... As always, take time to get a seasonal influenza vaccine as soon as flu vaccine becomes available in your community, to protect yourself from the seasonal influenza viruses that are most likely to circulate this ...

  7. Vaccine effectiveness in preventing laboratory-confirmed influenza in primary care patients in a season of co-circulation of influenza A(H1N1)pdm09, B and drifted A(H3N2), I-MOVE Multicentre Case-Control Study, Europe 2014/15.

    PubMed

    Valenciano, Marta; Kissling, Esther; Reuss, Annicka; Rizzo, Caterina; Gherasim, Alin; Horváth, Judit Krisztina; Domegan, Lisa; Pitigoi, Daniela; Machado, Ausenda; Paradowska-Stankiewicz, Iwona Anna; Bella, Antonino; Larrauri, Amparo; Ferenczi, Annamária; Lazar, Mihaela; Pechirra, Pedro; Korczyńska, Monika Roberta; Pozo, Francisco; Moren, Alain

    2016-01-01

    Influenza A(H3N2), A(H1N1)pdm09 and B viruses co-circulated in Europe in 2014/15. We undertook a multicentre case-control study in eight European countries to measure 2014/15 influenza vaccine effectiveness (VE) against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. General practitioners swabbed all or a systematic sample of ILI patients. We compared the odds of vaccination of ILI influenza positive patients to negative patients. We calculated adjusted VE by influenza type/subtype, and age group. Among 6,579 ILI patients included, 1,828 were A(H3N2), 539 A(H1N1)pdm09 and 1,038 B. VE against A(H3N2) was 14.4% (95% confidence interval (CI): -6.3 to 31.0) overall, 20.7% (95%CI: -22.3 to 48.5), 10.9% (95%CI -30.8 to 39.3) and 15.8% (95% CI: -20.2 to 41.0) among those aged 0-14, 15-59 and  ≥60  years, respectively. VE against A(H1N1)pdm09 was 54.2% (95%CI: 31.2 to 69.6) overall, 73.1% (95%CI: 39.6 to 88.1), 59.7% (95%CI: 10.9 to 81.8), and 22.4% (95%CI: -44.4 to 58.4) among those aged 0-14, 15-59 and  ≥60 years respectively. VE against B was 48.0% (95%CI: 28.9 to 61.9) overall, 62.1% (95%CI: 14.9 to 83.1), 41.4% (95%CI: 6.2 to 63.4) and 50.4% (95%CI: 14.6 to 71.2) among those aged 0-14, 15-59 and ≥60 years respectively. VE against A(H1N1)pdm09 and B was moderate. The low VE against A(H3N2) is consistent with the reported mismatch between circulating and vaccine strains.

  8. Genetics, evolution, and the zoonotic capacity of European Swine influenza viruses.

    PubMed

    Zell, Roland; Scholtissek, Christoph; Ludwig, Stephan

    2013-01-01

    The European swine influenza virus lineage differs genetically from the classical swine influenza viruses and the triple reassortants found in North America and Asia. The avian-like swine H1N1 viruses emerged in 1979 after an avian-to-swine transmission and spread to all major European pig-producing countries. Reassortment of these viruses with seasonal H3N2 viruses led to human-like swine H3N2 viruses which appeared in 1984. Finally, human-like swine H1N2 viruses emerged in 1994. These are triple reassortants comprising genes of avian-like H1N1, seasonal H1N1, and seasonal H3N2 viruses. All three subtypes established persistent infection chains and became prevalent in the European pig population. They successively replaced the circulating classical swine H1N1 viruses of that time and gave rise to a number of reassortant viruses including the pandemic (H1N1) 2009 virus. All three European lineages have the capacity to infect humans but zoonotic infections are benign.

  9. Multiple lineages of antigenically and genetically diverse influenza A virus co-circulate in the United States swine population.

    PubMed

    Webby, R J; Rossow, K; Erickson, G; Sims, Y; Webster, R

    2004-07-01

    Before the isolation of H3N2 viruses in 1998, swine influenza in the United States was an endemic disease caused exclusively by classical-swine H1N1 viruses. In this study we determined the antigenic and phylogenetic composition of a selection of currently circulating strains and revealed that, in contrast to the situation pre-1998, the swine population in the United States is now a dynamic viral reservoir containing multiple viral lineages. H3N2 viruses still circulate and representatives of each of two previously identified phylogenetic groups were isolated. H1N1 and H1N2 viruses were also identified. In addition to the genotypic diversity present, there was also considerable antigenic diversity seen. At least three antigenic profiles of H1 viruses were noted and all of the recent H3N2 viruses reacted poorly, if at all, to the index A/swine/Texas/4199-2/98 H3N2 antiserum in hemagglutination inhibition assays. The influenza reservoir in the United States swine population has thus gone from a stable single viral lineage to one where genetically and antigenically heterogenic viruses co-circulate. The growing complexity of influenza at this animal-human interface and the presence of viruses with a seemingly high affinity for reassortment makes the United States swine population an increasingly important reservoir of viruses with human pandemic potential.

  10. 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

  11. Kinetics of reactions of antihemagglutinin and antineuraminidase antibodies with H2N2 and H3N2 influenza virus strains and description of a modification of the photometric ACU method for titration of antineuraminidase antibodies.

    PubMed

    Drescher, J; Desselberger, U

    1976-01-01

    The isotherms describing the reactions of selected H2N2 and H3N2 virus strains with antihemagglutinin (AH) and antineuraminidase (AN) antibodies were established by use of a photometric hemagglutination inhibition test [antibody concentration unit (ACU) method]. It was found that the AN antibody isotherms had significantly higher values of the constant 1/N than did the AH antibody isotherms. This finding confirms for further virus strains the conclusion that the photometric ACU method can discriminate objectively between AN and AH antibodies. The results obtained when determining by use of the photometric ACU method the kinetics of reactions of AN antibodies oriented to A/Bel (HO)-A/Sing (N2) virus with the neuraminidases of H2N2 and H3N2 strains, and vice versa, indicated that the N2 neuraminidases of the test strains could be divided into the following groups: One group comprising the strains A/Sing/1/57 and A/AA/1/65, a second comprising the strains A/Hong Kong/1/68 and A/England/42/72 and a third represented by A/Port Chalmers/1/73. This finding indicated progressive antigenic variation of the neuraminidases of the strains tested. A modification of the photometric ACU method for the titration of AN antibodies oriented to N2 strains has been developed. The modified technique was found to be more sensitive and accurate than was AN antibody titration by means of enzyme inhibition and HI pattern test.

  12. 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.

  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. History and epidemiology of Swine influenza in Europe.

    PubMed

    Brown, Ian H

    2013-01-01

    In Europe, swine influenza is considered one of the most important primary pathogens of swine respiratory disease and infection is primarily with H1N1, H1N2 and H3N2 influenza A viruses. The antigenetic characteristics of these viruses distinguish them from others circulating at a global level in pigs. These viruses have remained endemic in European pig populations but significant differences in the circulation of these strains occur at a regional level across Europe. The dynamic of co-circulation of viruses, impact of prior immunity, husbandry practices and other local factors all contribute to the complex epidemiology. Surveillance programmes in European pigs did not reveal the presence of pandemic H1N1 virus prior to its detection in humans in 2009 but there is evidence that the virus can be maintained in European pigs even when there are relatively good levels of herd immunity to other H1 viruses. Evidence for the pig as a 'mixing vessel' of influenza viruses of non-swine-origin has been demonstrated in Europe on several occasions. Furthermore significant and highly variable genetic diversity occurs at the whole genome level for all virus subtypes and this has contributed to changing patterns of virus epidemiology over time.

  15. 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.

  16. Swine Influenza Virus: Emerging Understandings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: In March-April 2009, a novel pandemic H1N1 emerged in the human population in North America [1]. The gene constellation of the emerging virus was demonstrated to be a combination of genes from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before...

  17. 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.

  18. Variant (Swine Origin) Influenza Viruses in Humans

    MedlinePlus

    ... What's this? Submit Button Past Newsletters Variant Influenza Viruses: Background and CDC Risk Assessment and Reporting Language: ... Background CDC Assessment Reporting Background On Variant Influenza Viruses Swine flu viruses do not normally infect humans. ...

  19. Airborne Influenza A Is Detected in the Personal Breathing Zone of Swine Veterinarians

    PubMed Central

    O’Brien, Kate M.; Nonnenmann, Matthew W.

    2016-01-01

    The 2009 H1N1 pandemic emphasized a need to evaluate zoonotic transmission of influenza A in swine production. Airborne influenza A virus has been detected in swine facilities during an outbreak. However, the personal exposure of veterinarians treating infected swine has not been characterized. Two personal bioaerosol samplers, the NIOSH bioaerosol sampler and the personal high-flow inhalable sampler head (PHISH), were placed in the breathing zone of veterinarians treating swine infected with either H1N1 or H3N2 influenza A. A greater number of viral particles were recovered from the NIOSH bioaerosol sampler (2094 RNA copies/m3) compared to the PHISH sampler (545 RNA copies/m3). In addition, the majority of viral particles were detected by the NIOSH bioaerosol sampler in the >4 μm size fraction. These results suggest that airborne influenza A virus is present in the breathing zone of veterinarians treating swine, and the aerosol route of zoonotic transmission of influenza virus should be further evaluated among agricultural workers. PMID:26867129

  20. Rapid detection and differentiation of swine-origin influenza A virus (H1N1/2009) from other seasonal influenza A viruses.

    PubMed

    Zhao, Jiangqin; Wang, Xue; Ragupathy, Viswanath; Zhang, Panhe; Tang, Wei; Ye, Zhiping; Eichelberger, Maryna; Hewlett, Indira

    2012-11-09

    We previously developed a rapid and simple gold nanoparticle(NP)-based genomic microarray assay for identification of the avian H5N1 virus and its discrimination from other influenza A virus strains (H1N1, H3N2). In this study, we expanded the platform to detect the 2009 swine-origin influenza A virus (H1N1/2009). Multiple specific capture and intermediate oligonucleotides were designed for the matrix (M), hemagglutinin (HA), and neuraminidase (NA) genes of the H1N1/2009 virus. The H1N1/2009 microarrays were printed in the same format as those of the seasonal influenza H1N1 and H3N2 for the HA, NA, and M genes. Viral RNA was tested using capture-target-intermediate oligonucleotide hybridization and gold NP-mediated silver staining. The signal from the 4 capture-target-intermediates of the HA and NA genes was specific for H1N1/2009 virus and showed no cross hybridization with viral RNA from other influenza strains H1N1, H3N2, and H5N1. All of the 3 M gene captures showed strong affinity with H1N1/2009 viral RNA, with 2 out of the 3 M gene captures showing cross hybridization with the H1N1, H3N2, and H5N1 samples tested. The current assay was able to detect H1N1/2009 and distinguish it from other influenza A viruses. This new method may be useful for simultaneous detection and subtyping of influenza A viruses and can be rapidly modified to detect other emerging influenza strains in public health settings.

  1. 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

    2013-01-01

    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.

  2. Egg-adaptive mutations in H3N2v vaccine virus enhance egg-based production without loss of antigenicity or immunogenicity

    PubMed Central

    Barman, Subrata; Franks, John; Turner, Jasmine C.; Yoon, Sun-Woo; Webster, Robert G.; Webby, Richard J.

    2015-01-01

    The recently detected zoonotic H3N2 variant influenza A (H3N2v) viruses have caused 343 documented cases of human infection linked to contact with swine. An effective vaccine is needed for these viruses, which may acquire transmissibility among humans. However, viruses isolated from human cases do not replicate well in embryonated chicken eggs, posing an obstacle to egg-based vaccine production. To address this issue, we sought to identify egg-adaptive mutations in surface proteins that increase the yield of candidate vaccine viruses (CVVs) in eggs while preserving their immunizing effectiveness. After serial passage of a representative H3N2v isolate (A/Indiana/08/2011), we identified several egg-adaptive combinations of HA mutations and assessed the egg-based replication, antigenicity, and immunogenicity of A/Puerto Rico/8/34 (H1N1, PR8)-based 6 + 2 reverse genetics CVVs carrying these mutations. Here we demonstrate that the respective combined HA substitutions G1861V + N2461K, N1651K + G1861V, T1281N + N1651K + R762G, and T1281N + N1651K + I102M, all identified after egg passage, enhanced the replication of the CVVs in eggs without substantially affecting their antigenicity or immunogenicity. The mutations were stable, and the mutant viruses acquired no additional substitutions during six subsequent egg passages. We found two crucial mutations, G186V, which was previously defined, and N246K, which in combination improved virus yield in eggs without significantly impacting antigenicity or immunogenicity. This combination of egg-adaptive mutations appears to most effectively generate high egg-based yields of influenza A/Indiana/08/2011-like CVVs. PMID:25999284

  3. WHO recommendations for the viruses used in the 2013-2014 Northern Hemisphere influenza vaccine: Epidemiology, antigenic and genetic characteristics of influenza A(H1N1)pdm09, A(H3N2) and B influenza viruses collected from October 2012 to January 2013.

    PubMed

    Barr, Ian G; Russell, Colin; Besselaar, Terry G; Cox, Nancy J; Daniels, Rod S; Donis, Ruben; Engelhardt, Othmar G; Grohmann, Gary; Itamura, Shigeyuki; Kelso, Anne; McCauley, John; Odagiri, Takato; Schultz-Cherry, Stacey; Shu, Yuelong; Smith, Derek; Tashiro, Masato; Wang, Dayan; Webby, Richard; Xu, Xiyan; Ye, Zhiping; Zhang, Wenqing

    2014-08-20

    In February the World Health Organisation (WHO) recommends influenza viruses to be included in influenza vaccines for the forthcoming winter in the Northern Hemisphere. These recommendations are based on data collected by National Influenza Centres (NICs) through the WHO Global Influenza Surveillance and Response System (GISRS) and a more detailed analysis of representative and potential antigenically variant influenza viruses from the WHO Collaborating Centres for Influenza (WHO CCs) and Essential Regulatory Laboratories (ERLs). This article provides a detailed summary of the antigenic and genetic properties of viruses and additional background data used by WHO experts during development of the recommendations of the 2013-2014 Northern Hemisphere influenza vaccine composition.

  4. 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. PMID:26750204

  5. Reassortment patterns in Swine influenza viruses.

    PubMed

    Khiabanian, Hossein; Trifonov, Vladimir; Rabadan, Raul

    2009-10-07

    Three human influenza pandemics occurred in the twentieth century, in 1918, 1957, and 1968. Influenza pandemic strains are the results of emerging viruses from non-human reservoirs to which humans have little or no immunity. At least two of these pandemic strains, in 1957 and in 1968, were the results of reassortments between human and avian viruses. Also, many cases of swine influenza viruses have reportedly infected humans, in particular, the recent H1N1 influenza virus of swine origin, isolated in Mexico and the United States. Pigs are documented to allow productive replication of human, avian, and swine influenza viruses. Thus it has been conjectured that pigs are the "mixing vessel" that create the avian-human reassortant strains, causing the human pandemics. Hence, studying the process and patterns of viral reassortment, especially in pigs, is a key to better understanding of human influenza pandemics. In the last few years, databases containing sequences of influenza A viruses, including swine viruses, collected since 1918 from diverse geographical locations, have been developed and made publicly available. In this paper, we study an ensemble of swine influenza viruses to analyze the reassortment phenomena through several statistical techniques. The reassortment patterns in swine viruses prove to be similar to the previous results found in human viruses, both in vitro and in vivo, that the surface glycoprotein coding segments reassort most often. Moreover, we find that one of the polymerase segments (PB1), reassorted in the strains responsible for the last two human pandemics, also reassorts frequently.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25701826

  7. 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.

  8. Exploration of risk factors contributing to the presence of influenza A virus in swine at agricultural fairs.

    PubMed

    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.

  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. First report of seroprevalence of swine influenza A virus in Tibetan pigs in Tibet, China.

    PubMed

    Liu, Guo-Hua; Zhou, Dong-Hui; Cong, Wei; Zhang, Xiao-Xuan; Shi, Xin-Chun; Danba, Ciren; Huang, Si-Yang; Zhu, Xing-Quan

    2014-01-01

    Swine influenza A virus (SIV) is zoonotic pathogen that can be acquired by food-borne transmission because food animals, for example pigs, are recognized as a reservoir. The objectives of this study were to determine the seroprevalence of anti-SIV (H1N1 and H3N2) in Tibetan pigs in Tibet Nationality Autonomous Region, China, a region with cold weather and high altitude. A total of 421 serum samples were randomly collected from Tibetan pigs in Tibet and were evaluated for antibodies against SIV using enzyme-linked immunosorbent assay. Overall, 52 % (219/421) of the animals was positive for H1N1, 16.9 % (71/421) positive for H3N2, and 8.8 % (37/421) positive for both H1N1 and H3N2. The results of the present survey indicated that SIV is highly prevalent among Tibetan pigs in Tibet, China. The results of the present investigation have implications for the ongoing control of SIV infection in Tibetan pigs in Tibet, China and elsewhere.

  11. Swine Worker Precautions During Suspected Outbreaks of Influenza in Swine.

    PubMed

    Paccha, Blanca; Neira-Ramirez, Victor; Gibbs, Shawn; Torremorell, Montserrat; Rabinowitz, Peter M

    2016-05-01

    To assess the behavior and precautions that swine workers take during suspected influenza outbreaks in swine, six commercial swine farms in the Midwest U.S. region were visited when influenza outbreaks were suspected in herds during the fall/winter of 2012-2013. Use of personal protective equipment (PPE) and type of task performed by swine workers were recorded based on farm representative reports. Between one to two workers were working on the day of each visit and spent approximately 25 minutes performing work-related tasks that placed them in close contact with the swine. The most common tasks reported were walking the aisles (27%), handling pigs (21%), and handling equipment (21%). The most common PPE were boots (100%), heavy rubber gloves (75%), and dedicated nondisposable clothing (74%). Use of N95 respirators was reported at three farms. Hand hygiene practices were common in most of the farms, but reportedly performed for only 20% to 25% of tasks. PMID:27263180

  12. Vaccination of pigs against swine influenza viruses by using an NS1-truncated modified live-virus vaccine.

    PubMed

    Richt, Jürgen A; Lekcharoensuk, Porntippa; Lager, Kelly M; Vincent, Amy L; Loiacono, Christina M; Janke, Bruce H; Wu, Wai-Hong; Yoon, Kyoung-Jin; Webby, Richard J; Solórzano, Alicia; García-Sastre, Adolfo

    2006-11-01

    Swine influenza viruses (SIV) naturally infect pigs and can be transmitted to humans. In the pig, genetic reassortment to create novel influenza subtypes by mixing avian, human, and swine influenza viruses is possible. An SIV vaccine inducing cross-protective immunity between different subtypes and strains circulating in pigs is highly desirable. Previously, we have shown that an H3N2 SIV (A/swine/Texas/4199-2/98 [TX98]) containing a deleted NS1 gene expressing a truncated NS1 protein of 126 amino acids, NS1black triangle126, was attenuated in swine. In this study, 4-week-old pigs were vaccinated with the TX98 NS1black triangle126 modified live virus (MLV). Ten days after boosting, pigs were challenged with wild-type homologous H3N2 or heterosubtypic H1N1 SIV and sacrificed 5 days later. The MLV was highly attenuated and completely protected against challenge with the homologous virus. Vaccinated pigs challenged with the heterosubtypic H1N1 virus demonstrated macroscopic lung lesions similar to those of the unvaccinated H1N1 control pigs. Remarkably, vaccinated pigs challenged with the H1N1 SIV had significantly lower microscopic lung lesions and less virus shedding from the respiratory tract than did unvaccinated, H1N1-challenged pigs. All vaccinated pigs developed significant levels of hemagglutination inhibition and enzyme-linked immunosorbent assay titers in serum and mucosal immunoglobulin A antibodies against H3N2 SIV antigens. Vaccinated pigs were seronegative for NS1, indicating the potential use of the TX98 NS1black triangle126 MLV as a vaccine to differentiate infected from vaccinated animals.

  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. Vaccine escape in 2013-4 and the hydropathic evolution of glycoproteins of A/H3N2 viruses

    NASA Astrophysics Data System (ADS)

    Phillips, J. C.

    2016-08-01

    More virulent strains of influenza virus subtypes H1N1 appeared widely in 2007 and H3N2 in 2011, and especially 2013-4, when the effectiveness of the H3N2 vaccine decreased by more than a factor of two. The amino acid differences of neuraminidase from prior less virulent strains appear to be small (<1%) when tabulated through sequence alignments and counting site identities and similarities. Here we show how analyzing fractal hydropathic forces responsible for neuraminidase globular compaction and modularity quantifies the mutational origins of increased virulence. It also predicts vaccine escape and specifies optimized targets for the 2015 H3N2 vaccine. Unlike some earlier methods based on measuring hemagglutinin antigenic drift, which take several years, cover only a few candidate strains, and are ambiguous, the new methods are timely and can be completed, using NCBI and GISAID amino acid sequences only, in a few days.

  15. Protective efficacy of a broadly cross-reactive swine influenza DNA vaccine encoding M2e, cytotoxic T lymphocyte epitope and consensus H3 hemagglutinin

    PubMed Central

    2012-01-01

    Background Pigs have been implicated as mixing reservoir for the generation of new pandemic influenza strains, control of swine influenza has both veterinary and public health significance. Unlike human influenza vaccines, strains used for commercially available swine influenza vaccines are not regularly replaced, making the vaccines provide limited protection against antigenically diverse viruses. It is therefore necessary to develop broadly protective swine influenza vaccines that are efficacious to both homologous and heterologous virus infections. In this study, two forms of DNA vaccines were constructed, one was made by fusing M2e to consensus H3HA (MHa), which represents the majority of the HA sequences of H3N2 swine influenza viruses. Another was made by fusing M2e and a conserved CTL epitope (NP147-155) to consensus H3HA (MNHa). Their protective efficacies against homologous and heterologous challenges were tested. Results BALB/c mice were immunized twice by particle-mediated epidermal delivery (gene gun) with the two DNA vaccines. It was shown that the two vaccines elicited substantial antibody responses, and MNHa induced more significant T cell-mediated immune response than MHa did. Then two H3N2 strains representative of different evolutional and antigenic clusters were used to challenge the vaccine-immunized mice (homosubtypic challenge). Results indicated that both of the DNA vaccines prevented homosubtypic virus infections completely. The vaccines’ heterologous protective efficacies were further tested by challenging with a H1N1 swine influenza virus and a reassortant 2009 pandemic strain. It was found that MNHa reduced the lung viral titers significantly in both challenge groups, histopathological observation showed obvious reduction of lung pathogenesis as compared to MHa and control groups. Conclusions The combined utility of the consensus HA and the conserved M2e and CTL epitope can confer complete and partial protection against homologous and

  16. Prior infection of pigs with swine influenza viruses is a barrier to infection with avian influenza viruses.

    PubMed

    De Vleeschauwer, Annebel; Van Reeth, Kristien

    2010-12-15

    Although pigs are susceptible to avian influenza viruses (AIV) of different subtypes, the incidence of AIV infections in the field appears to be low. Swine H1N1, H3N2 and H1N2 influenza viruses (SIV) are enzootic worldwide and most pigs have antibodies to 1 or more SIV subtypes. This study aimed to examine whether infection-immunity to H1N1 or H3N2 SIV may (1) protect pigs against subsequent infections with AIV of various haemagglutinin and/or neuraminidase subtypes and/or (2) interfere with the serological diagnosis of AIV infection by haemagglutination inhibition (HI) or virus neutralization (VN) tests. Pigs were inoculated intranasally with an H1N1 or H3N2 SIV or left uninoculated. Four or 6 weeks later all pigs were challenged intranasally with 1 of 3 AIV subtypes (H4N6, H5N2 or H7N1). Fifteen out of 17 challenge control pigs shed the respective AIV for 4-6 days post-inoculation and 16 developed HI and VN antibodies. In contrast, 28 of the 29 SIV-immune pigs did not have detectable AIV shedding. Only 12 SIV-immune pigs developed HI antibodies to the AIV used for challenge and 14 had VN antibodies. Antibody titres to the AIV were low in both control and SIV-immune pigs. Our data show that prior infection of pigs with SIV is a barrier to infection with AIV of unrelated subtypes. Serological screening in regions where SIV is enzootic is only useful when the AIV strain for which the pigs need to be tested is known.

  17. Influenza A virus and secondary bacterial infection in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A virus (IAV) infection alone causes significant disease characterized by respiratory distress and poor growth in pigs. Endemic strains of IAV in North America pigs consist of the subtypes H1N1, H1N2, and H3N2. These circulating strains contain the triple reassortant internal gene (TRIG) c...

  18. Novel Human-like Influenza A Viruses Circulate in Swine in Mexico and Chile

    PubMed Central

    Nelson, Martha; Culhane, Marie R.; Rovira, Albert; Torremorell, Montserrat; Guerrero, Pedro; Norambuena, Julio

    2015-01-01

    Introduction: Further understanding of the genetic diversity and evolution of influenza A viruses circulating in swine (IAV-S) is important for the development of effective vaccines and our knowledge of pandemic threats. Until recently, very little was known of IAV-S diversity in Latin America, owing to a lack of surveillance. Methods: To address this gap, we sequenced and conducted a phylogenetic analysis of 69 hemagglutinin (HA) sequences from IAV-S isolates collected in swine in Mexico and Chile during 2010-2014, including the H1N1, H1N2, and H3N2 subtypes. Results: Our analysis identified multiple IAV-S lineages that appear to have been circulating undetected in swine for decades, including four novel IAV-S lineages of human seasonal virus origin that have not been previously identified in any swine populations globally. We also found evidence of repeated introductions of pandemic H1N1 viruses from humans into swine in Mexico and Chile since 2009, and incursions of H1 and H3 viruses from North American swine into Mexico. Discussion: Overall, our findings indicate that at least 12 genetically distinct HA lineages circulate in Latin American swine herds, only two of which have been found in North American swine herds. Human-to-swine transmission, spatial migration via swine movements, and genomic reassortment are the key evolutionary mechanisms that generate this viral diversity. Additional antigenic characterization and whole-genome sequencing is greatly needed to understand the diversity and independent evolution of IAV-S in Latin America.  PMID:26345598

  19. Genetic characterization of Thai swine influenza viruses after the introduction of pandemic H1N1 2009.

    PubMed

    Charoenvisal, Nataya; Keawcharoen, Juthatip; Sreta, Donruethai; Chaiyawong, Supassama; Nonthabenjawan, Nutthawan; Tantawet, Siriporn; Jittimanee, Suphattra; Arunorat, Jirapat; Amonsin, Alongkorn; Thanawongnuwech, Roongroje

    2013-08-01

    Pandemic H1N1 2009 (pH1N1), influenza virus containing triple reassortant internal genes (TRIG) from avian, human, and swine influenza viruses emerged in 2009 as a highly infectious virus that was able to be transmitted from humans to pigs. During June 2010-May 2012, influenza virus surveillance was conducted in Thai pig population. Twenty-three samples (1.75%) were successfully isolated from total of 1,335 samples. Interestingly, pH1N1 (7 isolates, 30.34%), reassortant pH1N1 (rH1N1) (1 isolate, 4.35%), Thai endemic H1N1 (enH1N1) (3 isolates, 13.04%), reassortant H3N2 with pH1N1 internal genes (rH3N2) (9 isolates, 39.13%), and reassortant H1N2 with pH1N1 internal genes (rH1N2) (3 isolates, 13.04%) were found. It should be noted that rH1N1, rH1N2, and rH3N2 viruses contained the internal genes of pH1N1 virus having a TRIG cassette descendant from the North American swine lineage. Although all isolates in this study were obtained from mild clinically sick pigs, the viruses were still highly infective and possibly may play an important role in human-animal interfacing transmission. In addition, the TRIG cassette may have an influence on antigenic shift resulting in emergence of novel viruses, as seen in this study. Continuing surveillance of influenza A natural hosts, particularly in pigs is necessary.

  20. 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. PMID:26477456

  1. 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.

  2. Genetic composition of contemporary swine influenza viruses in the West Central region of the United States of America

    PubMed Central

    Evseenko, Vasiliy A.; Boon, Adrianus C. M.; Brockwell‐Staats, Christy; Franks, John; Rubrum, Adam; Daniels, Curt S.; Gramer, Marie R.; Webby, Richard J.

    2011-01-01

    Please cite this paper as: Evseenko et al. (2011) Genetic composition of contemporary swine influenza viruses in the West Central region of the United States of America. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2010.00189.x. Background  Because of continuous circulation in different animal species and humans, influenza viruses have host‐specific phenotypic and genetic features. Reassortment of the genome segments can significantly change virus phenotype, potentially generating virus with pandemic potential. In 2009, a new pandemic influenza virus emerged. Objectives  In this study, we attempted to find precursor viruses or genes of pandemic H1N1 influenza 2009 among 25 swine influenza viruses, isolated in the West Central region of the United States of America (USA), between 2007 and 2009. The Phylogenetically Similar Triple‐Reassortant Internal Genes (PSTRIG) cassette of all the viruses studied here as well as the PSTRIG cassette of pandemic H1N1 viruses have close but equidistant phylogenetic relationships to the early triple‐reassortant swine H3N2 influenza A isolated in the USA in 1998. Methods  Samples (nasal swabs and lung tissue lavage) were taken from swine with or without clinical signs of respiratory disease via farmer‐funded syndromic surveillance. All studied viruses were isolated in Madin–Darby Canine Kidney cell cultures from the above‐mentioned samples according to standard protocols recommended for influenza virus isolation. Sequences were obtained using BigDye Terminator v3.1 Cycle Sequencing kit. Phylogenetic trees were built with MEGA 4.0 software using maximum composite likelihood algorithm and neighbor‐joining method for tree topology reconstruction. Results  Among the 25 viruses studied, we have not found any gene segments of Eurasian origin. Our results suggest that pandemic H1N1 viruses diverged and are not directly descended from swine viruses that have been circulating in USA since 1998

  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.

  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. 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. PMID:26051886

  6. 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.

  7. Evidence of Cross-Reactive Immunity to 2009 Pandemic Influenza A Virus in Workers Seropositive to Swine H1N1 Influenza Viruses Circulating in Italy

    PubMed Central

    De Marco, Maria A.; Porru, Stefano; Cordioli, Paolo; Cesana, Bruno M.; Moreno, Ana; Calzoletti, Laura; Bonfanti, Lebana; Boni, Arianna; Di Carlo, Antonio Scotto; Arici, Cecilia; Carta, Angela; Castrucci, Maria R.; Donatelli, Isabella; Tomao, Paola; Peri, Vittoria M.; Di Trani, Livia; Vonesch, Nicoletta

    2013-01-01

    Background Pigs play a key epidemiologic role in the ecology of influenza A viruses (IAVs) emerging from animal hosts and transmitted to humans. Between 2008 and 2010, we investigated the health risk of occupational exposure to swine influenza viruses (SIVs) in Italy, during the emergence and spread of the 2009 H1N1 pandemic (H1N1pdm) virus. Methodology/Principal Findings Serum samples from 123 swine workers (SWs) and 379 control subjects (Cs), not exposed to pig herds, were tested by haemagglutination inhibition (HI) assay against selected SIVs belonging to H1N1 (swH1N1), H1N2 (swH1N2) and H3N2 (swH3N2) subtypes circulating in the study area. Potential cross-reactivity between swine and human IAVs was evaluated by testing sera against recent, pandemic and seasonal, human influenza viruses (H1N1 and H3N2 antigenic subtypes). Samples tested against swH1N1 and H1N1pdm viruses were categorized into sera collected before (n. 84 SWs; n. 234 Cs) and after (n. 39 SWs; n. 145 Cs) the pandemic peak. HI-antibody titers ≥10 were considered positive. In both pre-pandemic and post-pandemic peak subperiods, SWs showed significantly higher swH1N1 seroprevalences when compared with Cs (52.4% vs. 4.7% and 59% vs. 9.7%, respectively). Comparable HI results were obtained against H1N1pdm antigen (58.3% vs. 7.7% and 59% vs. 31.7%, respectively). No differences were found between HI seroreactivity detected in SWs and Cs against swH1N2 (33.3% vs. 40.4%) and swH3N2 (51.2 vs. 55.4%) viruses. These findings indicate the occurrence of swH1N1 transmission from pigs to Italian SWs. Conclusion/Significance A significant increase of H1N1pdm seroprevalences occurred in the post-pandemic peak subperiod in the Cs (p<0.001) whereas SWs showed no differences between the two subperiods, suggesting a possible occurrence of cross-protective immunity related to previous swH1N1 infections. These data underline the importance of risk assessment and occupational health surveillance activities aimed at

  8. 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

  9. 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

    2014-08-01

    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.

  10. Swine Influenza/Variant Influenza Viruses

    MedlinePlus

    ... Humans Key Facts about Human Infections with Variant Viruses Interim Guidance for Clinicians on Human Infections Background, Risk Assessment & Reporting Reported Infections with Variant Influenza Viruses in the United States since 2005 Prevention Treatment ...

  11. 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.

  12. Rapid genotyping of swine influenza viruses.

    PubMed

    Mak, Polly W Y; Wong, Chloe K S; Li, Olive T W; Chan, Kwok Hung; Cheung, Chung Lam; Ma, Edward S; Webby, Richard J; Guan, Yi; Malik Peiris, Joseph S; Poon, Leo L M

    2011-04-01

    The emergence of pandemic (H1N1) 2009 virus highlighted the need for enhanced surveillance of swine influenza viruses. We used real-time reverse-transcription PCR-based genotyping and found that this rapid and simple genotyping method may identify reassortants derived from viruses of Eurasian avian-like, triple reassortant-like, and pandemic (H1N1) 2009 virus lineages.

  13. Rapid Genotyping of Swine Influenza Viruses

    PubMed Central

    Mak, Polly W.Y.; Wong, Chloe K.S.; Li, Olive T.W.; Chan, Kwok Hung; Cheung, Chung Lam; Ma, Edward S.; Webby, Richard J.; Guan, Yi; Peiris, Joseph S. Malik

    2011-01-01

    The emergence of pandemic (H1N1) 2009 virus highlighted the need for enhanced surveillance of swine influenza viruses. We used real-time reverse–transcription PCR–based genotyping and found that this rapid and simple genotyping method may identify reassortants derived from viruses of Eurasian avian-like, triple reassortant-like, and pandemic (H1N1) 2009 virus lineages. PMID:21470462

  14. Characterization of Viral Load, Viability and Persistence of Influenza A Virus in Air and on Surfaces of Swine Production Facilities

    PubMed Central

    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. PMID:26757362

  15. 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. PMID:26757362

  16. Quantifying the global antigenic diversity of swine influenza A viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 wit...

  17. Global migration of influenza A viruses in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. Comparison of three serological assays to determine the cross-reactivity of antibodies from eight genetically diverse U.S. swine influenza viruses.

    PubMed

    Leuwerke, Brad; Kitikoon, Pravina; Evans, Richard; Thacker, Eileen

    2008-07-01

    Swine influenza virus is an economically important pathogen to the U.S. swine industry. New influenza subtypes and isolates within subtypes with different genetic and antigenic makeup have recently emerged in U.S. swineherds. As a result of the emergence of these new viruses, diagnosticians' ability to accurately diagnose influenza infection in pigs and develop appropriate vaccine strategies has become increasingly difficult. The current study compares the ability of subtype-specific commercial enzyme-linked immunosorbent assays (ELISA), hemagglutination inhibition (HI), and serum neutralization (SN) assays to detect antibodies elicited by multiple isolates within different subtypes of influenza virus. Pigs were infected with genetically and antigenically different isolates of the 3 major circulating subtypes within populations of swine (H1N1, H1N2, and H3N2). Serum was collected when all pigs within a group collectively reached HI reciprocal titers >or=160 against that group's homologous challenge virus. The antibody cross-reactivity of the sera between isolates was determined using ELISA, HI, and SN assays. In addition, the correlation between the 3 assays was determined. The assays differed in their ability to detect antibodies produced by the viruses used in the study. The results provide important information to diagnostic laboratories, veterinarians, and swine producers on the ability of 3 common serological assays used in identifying infection with influenza in pigs. PMID:18599846

  19. Airborne detection and quantification of swine influenza a virus in air samples collected inside, outside and downwind from swine barns.

    PubMed

    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.

  20. 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

  1. 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

    2010-10-01

    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. PMID:20708697

  2. 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

    2010-10-01

    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.

  3. 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

  4. 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

  5. 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.

  6. Molecular and antigenic characterization of reassortant H3N2 viruses from turkeys with a unique constellation of pandemic H1N1 internal genes.

    PubMed

    Berhane, Yohannes; Kehler, Helen; Handel, Katherine; Hisanaga, Tamiko; Xu, Wanhong; Ojkic, Davor; Pasick, John

    2012-01-01

    Triple reassortant (TR) H3N2 influenza viruses cause varying degrees of loss in egg production in breeder turkeys. In this study we characterized TR H3N2 viruses isolated from three breeder turkey farms diagnosed with a drop in egg production. The eight gene segments of the virus isolated from the first case submission (FAV-003) were all of TR H3N2 lineage. However, viruses from the two subsequent case submissions (FAV-009 and FAV-010) were unique reassortants with PB2, PA, nucleoprotein (NP) and matrix (M) gene segments from 2009 pandemic H1N1 and the remaining gene segments from TR H3N2. Phylogenetic analysis of the HA and NA genes placed the 3 virus isolates in 2 separate clades within cluster IV of TR H3N2 viruses. Birds from the latter two affected farms had been vaccinated with a H3N4 oil emulsion vaccine prior to the outbreak. The HAl subunit of the H3N4 vaccine strain had only a predicted amino acid identity of 79% with the isolate from FAV-003 and 80% for the isolates from FAV-009 and FAV-0010. By comparison, the predicted amino acid sequence identity between a prototype TR H3N2 cluster IV virus A/Sw/ON/33853/2005 and the three turkey isolates from this study was 95% while the identity between FAV-003 and FAV-009/10 isolates was 91%. When the previously identified antigenic sites A, B, C, D and E of HA1 were examined, isolates from FAV-003 and FAV-009/10 had a total of 19 and 16 amino acid substitutions respectively when compared with the H3N4 vaccine strain. These changes corresponded with the failure of the sera collected from turkeys that received this vaccine to neutralize any of the above three isolates in vitro.

  7. Enhanced Pneumonia and Proinflammatory Cytokine Response in Pigs Challenged with Pandemic 2009 A/H1N1 Influenza Virus Following Vaccination with an Inactivated delta-Cluster H1N2 Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endemic strains of swine influenza A virus (IAV) in North America consist of the subtypes H1N1, H1N2, and H3N2. These circulating strains contain the triple reassortant internal gene (TRIG) cassette resulting from incorporation of genes from swine, avian, and human IAV’s. Genetic drift and reassortm...

  8. Lessons learned from influenza in swine and poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza is naturally carried by wild birds, however it does occasionally transmit to domestic animal populations. Poultry and swine are the two major food animal populations which may be infected by influenza A. This report reviews the historic impact of these disease incursions. The actions taken...

  9. Influenza A virus pathogenesis and vaccination in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine influenza is an acute respiratory disease of pigs that is characterized by fever followed by lethargy, anorexia, and serous nasal discharge. The disease progresses rapidly and may be complicated when associated with other respiratory pathogens. Influenza A virus (IAV) is one of the most preval...

  10. Active surveillance for influenza A virus among swine, midwestern United States, 2009-2011.

    PubMed

    Corzo, Cesar A; Culhane, Marie; Juleen, Kevin; Stigger-Rosser, Evelyn; Ducatez, Mariette F; Webby, Richard J; Lowe, James F

    2013-06-01

    Veterinary diagnostic laboratories identify and characterize influenza A viruses primarily through passive surveillance. However, additional surveillance programs are needed. To meet this need, an active surveillance program was conducted at pig farms throughout the midwestern United States. From June 2009 through December 2011, nasal swab samples were collected monthly from among 540 groups of growing pigs and tested for influenza A virus by real-time reverse transcription PCR. Of 16,170 samples, 746 were positive for influenza A virus; of these, 18.0% were subtype H1N1, 16.0% H1N2, 7.6% H3N2, and 14.5% (H1N1)pdm09. An influenza (H3N2) and (H1N1)pdm09 virus were identified simultaneously in 8 groups. This active influenza A virus surveillance program provided quality data and increased the understanding of the current situation of circulating viruses in the midwestern US pig population.

  11. Pathogenesis and transmission studies: non-swine influenza A viruses in the swine host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract Influenza A virus (IAV) causes disease in poultry, pigs, and people with wild waterfowl being the natural reservoir. IAV strains have been periodically transmitted between swine and humans in both directions and avian IAV have also sporadically infected swine. If an individual is infected w...

  12. Influenza A virus in pigs – protection, provocation and predisposition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endemic strains of influenza A virus (IAV) in North America pigs consist of the subtypes H1N1, H1N2, and H3N2. These circulating strains contain the triple reassortant internal gene (TRIG) cassette resulting from incorporation of genes from swine, avian, and human IAV's. Genetic drift and reassortme...

  13. 76 FR 81467 - Availability of an Environmental Assessment for Field Testing Swine Influenza Vaccine, RNA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-28

    ... Swine Influenza Vaccine, RNA AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice... test, an unlicensed Swine Influenza Vaccine, RNA. The environmental assessment, which is based on a...: Requester: Harrisvaccines, Inc. Product: Swine Influenza Vaccine, RNA. Field Test Locations: North...

  14. Determination of current reference viruses for serological study of swine influenza viruses after the introduction of pandemic 2009 H1N1 (pdmH1N1) in Thailand.

    PubMed

    Arunorat, Jirapat; Charoenvisal, Nataya; Woonwong, Yonlayong; Kedkovid, Roongtham; Thanawongnuwech, Roongroje

    2016-10-01

    Since the introduction of pandemic H1N1 2009 virus (pdmH1N1) in pigs, the status of Thai swine influenza virus (SIV) has changed. The pdmH1N1 and its reassortant viruses have become the predominant strain circulating in the Thai swine population based on the surveillance data from 2012 to 2014. For this reason, the reference viruses for serological assays using the hemagglutination inhibition (HI) test needed to be updated. Six anti-sera against reference viruses from 2006 to 2009 (enH1N1-06, enH1N1-09, enH1N2-09, pdmH1N1-09, enH3N2-07 and enH3N2-09) were used for the HI test with four contemporary viruses (enH1N1-10, pdmH1N1-10, rH1N2 and rH3N2) and the selected reference viruses were tested with sera collected from the field to determine the current SIV status. The results showed that anti-sera of swH1N1-06 had the highest titers against enH1N1-10. Anti-sera of pdmH1N1-09 had the highest titers against pdmH1N1-10 and rH1N2, whereas, anti-sera of enH3N2-09 had the highest titers against rH3N2. The results demonstrated that enH1N1-06, pdmH1N1-09 and enH3N2-09 should be selected as reference viruses for contemporary serological studies and HI tests. The seroprevalence results from 410 samples revealed enH1N1 (37.79%), pdmH1N1 (37.32%) and H3N2 (35.86%), respectively. The present study indicated that pdmH1N1 was widespread and commonly found in the Thai pig population increasing the risk of novel reassortant viruses and should be added as a reference virus for HI test. SIV surveillance program and serological studies should be conducted for the benefits of SIV control and prevention as well as monitoring for zoonotic potential. PMID:27355862

  15. 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

  16. Inhibitory influence of Enterococcus faecium on the propagation of swine influenza A virus in vitro.

    PubMed

    Wang, Zhenya; Chai, Weidong; Burwinkel, Michael; Twardziok, Sven; Wrede, Paul; Palissa, Christiane; Esch, Bettina; Schmidt, Michael F G

    2013-01-01

    The control of infectious diseases such as swine influenza viruses (SwIV) plays an important role in food production both from the animal health and from the public health point of view. Probiotic microorganisms and other health improving food supplements have been given increasing attention in recent years, but, no information on the effects of probiotics on swine influenza virus is available. Here we address this question by assessing the inhibitory potential of the probiotic Enterococcus faecium NCIMB 10415 (E. faecium) on the replication of two porcine strains of influenza virus (H1N1 and H3N2 strain) in a continuous porcine macrophage cell line (3D4/21) and in MDBK cells. Cell cultures were treated with E. faecium at the non-toxic concentration of 1×10(6) CFU/ml in growth medium for 60 to 90 min before, during and after SwIV infection. After further incubation of cultures in probiotic-free growth medium, cell viability and virus propagation were determined at 48 h or 96 h post infection. The results obtained reveal an almost complete recovery of viability of SwIV infected cells and an inhibition of virus multiplication by up to four log units in the E. faecium treated cells. In both 3D4/21- and MDBK-cells a 60 min treatment with E. faecium stimulated nitric oxide (NO) release which is in line with published evidence for an antiviral function of NO. Furthermore, E. faecium caused a modified cellular expression of selected mediators of defence in 3D4-cells: while the expression of TNF-α, TLR-3 and IL-6 were decreased in the SwIV-infected and probiotic treated cells, IL-10 was found to be increased. Since we obtained experimental evidence for the direct adsorptive trapping of SwIV through E. faecium, this probiotic microorganism inhibits influenza viruses by at least two mechanisms, direct physical interaction and strengthening of innate defence at the cellular level.

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

    PubMed Central

    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

    2012-01-01

    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 HA225G and NA315N 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 HA225G and NA315N as potential virulence markers in mammals. PMID:23019374

  18. Outbreak of influenza A (H3N2) in people and pigs at county fairs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On July 11, 2012 a fair veterinarian was requested to examine an ill pig in the show barn. The following day additional pigs were reported as listless, anorexic, and febrile (up to 107F). The Board of Animal Health was notified of the situation on July 12th. Approximately 280 pigs were in attendance...

  19. An Epizootic of Swine Influenza in Ontario

    PubMed Central

    Sanford, S. E.; Josephson, G. K. A.; Key, D. W.

    1983-01-01

    A swine influenza virus (H1N1) was isolated for the first time in Ontario from pigs one week to one and one-half years old during an epizootic which occurred between January and May 1981. Each herd outbreak was characterized by the sudden onset of marked respiratory distress, usually affecting the entire herd, accompanied by paroxysmal coughing, anorexia, prostration and temperatures as high as 41.5°C and lasting for five to seven days. Morbidity was nearly 100%; mortality was less than 1%. Hematology, bacteriology and postmortem studies were conducted on 18 pigs from 11 farms. A lymphopenia and acute hematological inflammatory cellular responses characterized by neutrophilia with a left shift, hyperfibrinogenemia and a decreased plasma protein: fibrinogen ratio were found in 50% of the pigs. The cranial lobes of the lung were collapsed and red due to a bilateral cranioventral pneumonia which affected the cranial, middle, accessory and cranioventral aspects of the caudal lobes. Histologically, there was a necrotizing bronchitis and bronchiolitis with a neutrophilic cellular exudate. Pasteurella multocida was the species of bacterium most frequently isolated from the lung; however, mixed cultures of P. multocida frequently combined with Corynebacterium pyogenes and other species were usually identified in the lung and other organs of pigs submitted dead. ImagesFigure 2.Figure 3.Figure 4. PMID:17422266

  20. From where did the 2009 'swine-origin' influenza A virus (H1N1) emerge?

    PubMed

    Gibbs, Adrian J; Armstrong, John S; Downie, Jean C

    2009-11-24

    The swine-origin influenza A (H1N1) virus that appeared in 2009 and was first found in human beings in Mexico, is a reassortant with at least three parents. Six of the genes are closest in sequence to those of H1N2 'triple-reassortant' influenza viruses isolated from pigs in North America around 1999-2000. Its other two genes are from different Eurasian 'avian-like' viruses of pigs; the NA gene is closest to H1N1 viruses isolated in Europe in 1991-1993, and the MP gene is closest to H3N2 viruses isolated in Asia in 1999-2000. The sequences of these genes do not directly reveal the immediate source of the virus as the closest were from isolates collected more than a decade before the human pandemic started. The three parents of the virus may have been assembled in one place by natural means, such as by migrating birds, however the consistent link with pig viruses suggests that human activity was involved. We discuss a published suggestion that unsampled pig herds, the intercontinental live pig trade, together with porous quarantine barriers, generated the reassortant. We contrast that suggestion with the possibility that laboratory errors involving the sharing of virus isolates and cultured cells, or perhaps vaccine production, may have been involved. Gene sequences from isolates that bridge the time and phylogenetic gap between the new virus and its parents will distinguish between these possibilities, and we suggest where they should be sought. It is important that the source of the new virus be found if we wish to avoid future pandemics rather than just trying to minimize the consequences after they have emerged. Influenza virus is a very significant zoonotic pathogen. Public confidence in influenza research, and the agribusinesses that are based on influenza's many hosts, has been eroded by several recent events involving the virus. Measures that might restore confidence include establishing a unified international administrative framework coordinating

  1. Expanded cocirculation of stable subtypes, emerging lineages, and new sporadic reassortants of porcine influenza viruses in swine populations in Northwest Germany.

    PubMed

    Harder, Timm C; Grosse Beilage, Elisabeth; Lange, Elke; Meiners, Carolin; Döhring, Stefanie; Pesch, Stefan; Noé, Thomas; Grund, Christian; Beer, Martin; Starick, Elke

    2013-10-01

    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.

  2. [On-microchip PCR for detection of influenza A viruses subtypes, circulating in the human population].

    PubMed

    Kostina, E V; Ryabinin, V A; Ternovoi, V A; Sinyakov, A N

    2015-01-01

    A oligonucleotide microchip was developed for revealing Influenza A viruses subtypes, circulating in human population: pandemic H1N1 swine influenza viruses, seasonal H1N1, H2N2, H3N2, H5N1, H9N2, H7N9. Typing of influenza virus was performed by on-microchip PCR. We used immobilized primers-probes selected for the neuraminidase gene that allows determining both subtype of neuraminidase and subtype of hemagglutinin. PMID:26050481

  3. [On-microchip PCR for detection of influenza A viruses subtypes, circulating in the human population].

    PubMed

    Kostina, E V; Ryabinin, V A; Ternovoi, V A; Sinyakov, A N

    2015-01-01

    A oligonucleotide microchip was developed for revealing Influenza A viruses subtypes, circulating in human population: pandemic H1N1 swine influenza viruses, seasonal H1N1, H2N2, H3N2, H5N1, H9N2, H7N9. Typing of influenza virus was performed by on-microchip PCR. We used immobilized primers-probes selected for the neuraminidase gene that allows determining both subtype of neuraminidase and subtype of hemagglutinin.

  4. Characterization of co-circulating swine influenza A viruses in North America and the identification of a novel H1 genetic clade with antigenic significance.

    PubMed

    Anderson, Tavis K; Campbell, Brian A; Nelson, Martha I; Lewis, Nicola S; Janas-Martindale, Alicia; Killian, Mary Lea; Vincent, Amy L

    2015-04-01

    Multiple genetically and antigenically distinct hemagglutinin genes of the H1 and H3 influenza A virus (IAV) subtypes co-circulate in North American swine. This diversity has evolved by repeated transmission of IAVs from humans to swine and subsequent antigenic drift in swine. To understand the evolutionary dynamics of these diverse HA lineages in North American swine, we undertook a phylogenetic analysis of 1576 H1 and 607 H3 HA gene segments, as well as 834 N1 and 1293 N2 NA gene segments, and 2126 M gene segments. These data revealed yearly co-circulation of H1N1, H1N2, and H3N2 viruses, with three HA clades representing the majority of the HA sequences: of the H1 viruses, 42% were classified as H1δ1 and 40.6% were classified as H1γ; and of the H3 viruses 53% were classified as cluster IV-A H3N2. We detected a genetically distinct minor clade consisting of 37 H1 viruses isolated between 2003 and 2013, which we classified as H1γ-2. We estimated that this clade circulated in swine since approximately 1995, but it was not detected in swine until 2003. Though this clade only represents 1.07% of swine H1 sequences reported over the past 10 years, hemagglutination inhibition (HI) assays demonstrated that representatives of this clade of viruses are antigenically distinct, and, when measured using antigenic cartography, were as many as 7 antigenic units from other H1γ viruses. Therefore vaccines against the contemporary H1γ viruses are not likely to cross-protect against γ-2 viruses. The long-term circulation of these γ-2 viruses suggests that minor populations of viruses may be underreported in the national dataset given the long branch lengths and gaps in detections. The identification of these γ-2 viruses demonstrates the need for robust surveillance to capture the full diversity IAVs in swine in the USA and the importance of antigenic drift in the diversification and emergence of new antigenic variants in swine, which complicates vaccine design.

  5. 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

    2015-01-01

    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. PMID:26404790

  6. 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.

  7. Influenza Virus Surveillance in Coordinated Swine Production Systems, United States

    PubMed Central

    Kaplan, Bryan S.; DeBeauchamp, Jennifer; Stigger-Rosser, Evelyn; Franks, John; Crumpton, Jeri Carol; Turner, Jasmine; Darnell, Daniel; Jeevan, Trushar; Kayali, Ghazi; Harding, Abbey; Webby, Richard J.

    2015-01-01

    To clarify the epidemiology of influenza A viruses in coordinated swine production systems to which no animals from outside the system are introduced, we conducted virologic surveillance during September 2012–September 2013. Animal age, geographic location, and farm type were found to affect the prevalence of these viruses. PMID:26402228

  8. Coinfection of Pigs with Swine Influenza Virus and Bordetella bronchiseptica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coinfection with two or more pathogens is a common occurrence in respiratory diseases of most species. The manner in which these pathogens interact is not always straightforward, however. Bordetella bronchiseptica and swine influenza virus (SIV) are respiratory pathogens of pigs whose relatives, B...

  9. Coinfection with Swine Influenza Virus and Bordetella bronchiseptica in Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coinfection with two or more pathogens is a common occurrence in respiratory diseases of most species. The manner in which these pathogens interact is not always straightforward, however. Bordetella bronchiseptica and swine influenza virus (SIV) are respiratory pathogens of pigs whose relatives, B...

  10. 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

  11. 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

  12. Global migration of influenza A viruses in swine.

    PubMed

    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 neighbouring 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 United States 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

  13. Global migration of influenza A viruses in swine.

    PubMed

    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

    2015-03-27

    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 neighbouring 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 United States 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.

  14. Detection and Isolation of Swine Influenza A Virus in Spiked Oral Fluid and Samples from Individually Housed, Experimentally Infected Pigs: Potential Role of Porcine Oral Fluid in Active Influenza A Virus Surveillance in Swine

    PubMed Central

    Decorte, Inge; Steensels, Mieke; Lambrecht, Bénédicte

    2015-01-01

    Background The lack of seasonality of swine influenza A virus (swIAV) in combination with the capacity of swine to harbor a large number of co-circulating IAV lineages, resulting in the risk for the emergence of influenza viruses with pandemic potential, stress the importance of swIAV surveillance. To date, active surveillance of swIAV worldwide is barely done because of the short detection period in nasal swab samples. Therefore, more sensitive diagnostic methods to monitor circulating virus strains are requisite. Methods qRT-PCR and virus isolations were performed on oral fluid and nasal swabs collected from individually housed pigs that were infected sequentially with H1N1 and H3N2 swIAV strains. The same methods were also applied to oral fluid samples spiked with H1N1 to study the influence of conservation time and temperature on swIAV infectivity and detectability in porcine oral fluid. Results All swIAV infected animals were found qRT-PCR positive in both nasal swabs and oral fluid. However, swIAV could be detected for a longer period in oral fluid than in nasal swabs. Despite the high detectability of swIAV in oral fluid, virus isolation from oral fluid collected from infected pigs was rare. These results are supported by laboratory studies showing that the PCR detectability of swIAV remains unaltered during a 24 h incubation period in oral fluid, while swIAV infectivity drops dramatically immediately upon contact with oral fluid (3 log titer reduction) and gets lost after 24 h conservation in oral fluid at ambient temperature. Conclusions Our data indicate that porcine oral fluid has the potential to replace nasal swabs for molecular diagnostic purposes. The difficulty to isolate swIAV from oral fluid could pose a drawback for its use in active surveillance programs. PMID:26431039

  15. Cross-reactive immune responses following vaccination with a live-attenuated influenza virus compared to adjuvanted, whole-inactivated virus in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Circulating influenza A virus (IAV) in North America pigs consist of H3N2, H1N2, and H1N1 (4 genetic clusters) which contain the triple reassortant internal gene (TRIG) cassette resulting from incorporation of genes from swine, avian, and human IAV. Adjuvanted, whole-inactivated virus (WIV) vaccines...

  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.

  18. 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

  19. Spatial dynamics of human-origin H1 influenza A virus in North American swine.

    PubMed

    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

    2011-06-01

    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.

  20. Reverse zoonosis of influenza to swine: new perspectives on the human–animal interface

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Swine influenza in sub-saharan Africa--current knowledge and emerging insights.

    PubMed

    Meseko, C; Olaleye, D; Capua, I; Cattoli, G

    2014-06-01

    Pigs have been associated with several episodes of influenza outbreaks in the past and are considered to play a significant role in the ecology of influenza virus. The recent 2009 pandemic influenza A/H1N1 virus originated from swine and not only did it cause widespread infection in humans, but was also transmitted back to swine in Asia, Europe and America. What may be the prevailing situation in Africa, particularly in sub-Saharan Africa, with respect to the circulation of classical swine or pandemic influenza? The ecology of influenza viruses, as well as the epidemiology of human or animal influenza, is poorly understood in the region. In particular, little is known about swine influenza in Africa despite the relevance of this production in the continent and the widespread pig husbandry operations in urban and rural areas. In this review, the gap in the knowledge of classical and pandemic swine influenza is attributed to negligence of disease surveillance, as well as to the economic and public health impact that the disease may cause in sub-Saharan Africa. However, emerging serological and virological evidence of swine influenza virus in some countries in the region underscores the importance of integrated surveillance to better understand the circulation and epidemiology of swine influenza, a disease of global economic and public health importance.

  2. Transcription analysis on response of swine lung to H1N1 swine influenza virus

    PubMed Central

    2011-01-01

    Background As a mild, highly contagious, respiratory disease, swine influenza always damages the innate immune systems, and increases susceptibility to secondary infections which results in considerable morbidity and mortality in pigs. Nevertheless, the systematical host response of pigs to swine influenza virus infection remains largely unknown. To explore it, a time-course gene expression profiling was performed for comprehensive analysis of the global host response induced by H1N1 swine influenza virus in pigs. Results At the early stage of H1N1 swine virus infection, pigs were suffering mild respiratory symptoms and pathological changes. A total of 268 porcine genes showing differential expression (DE) after inoculation were identified to compare with the controls on day 3 post infection (PID) (Fold change ≥ 2, p < 0.05). The DE genes were involved in many vital functional classes, mainly including signal transduction, immune response, inflammatory response, cell adhesion and cell-cell signalling. Noticeably, the genes associated with immune and inflammatory response showed highly overexpressed. Through the pathway analysis, the significant pathways mainly concerned with Cell adhesion molecules, Cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway and MAPK signaling pathway, suggesting that the host took different strategies to activate these pathways so as to prevent virus infections at the early stage. However, on PID 7, the predominant function classes of DE genes included signal transduction, metabolism, transcription, development and transport. Furthermore, the most significant pathways switched to PPAR signaling pathway and complement and coagulation cascades, showing that the host might start to repair excessive tissue damage by anti-inflammatory functions. These results on PID 7 demonstrated beneficial turnover for host to prevent excessive inflammatory damage and recover the normal state by activating these clusters of genes

  3. The resurgence of swine-origin influenza A (H1N1).

    PubMed

    Mossad, Sherif Beniameen

    2009-06-01

    Unexpectedly, swine-origin influenza A (H1N1) virus (S-OIV, informally known as swine flu) appeared in North America at the very end of the 2008-2009 influenza season and began to spread internationally. As the world mobilizes for a potential pandemic, this article summarizes the developments in diagnosis, treatment, and prevention. PMID:19487554

  4. Active Surveillance for Influenza A Virus among Swine, Midwestern United States, 2009–2011

    PubMed Central

    Corzo, Cesar A.; Juleen, Kevin; Stigger-Rosser, Evelyn; Ducatez, Mariette F.; Webby, Richard J.; Lowe, James F.

    2013-01-01

    Veterinary diagnostic laboratories identify and characterize influenza A viruses primarily through passive surveillance. However, additional surveillance programs are needed. To meet this need, an active surveillance program was conducted at pig farms throughout the midwestern United States. From June 2009 through December 2011, nasal swab samples were collected monthly from among 540 groups of growing pigs and tested for influenza A virus by real-time reverse transcription PCR. Of 16,170 samples, 746 were positive for influenza A virus; of these, 18.0% were subtype H1N1, 16.0% H1N2, 7.6% H3N2, and 14.5% (H1N1)pdm09. An influenza (H3N2) and (H1N1)pdm09 virus were identified simultaneously in 8 groups. This active influenza A virus surveillance program provided quality data and increased the understanding of the current situation of circulating viruses in the midwestern US pig population. PMID:23735740

  5. Influenza A viruses: epidemiologic study in fatteners in Spain (1987-89).

    PubMed

    Yus, E; Sanjuan, M L; García, F; Castro, J M; Simarro, I

    1992-03-01

    2,979 sera were collected from slaughtered swine in two geographic areas of Spain from 1987 to 1989. They were tested for antibodies against an H1N1- and H3N2-influenza virus by haemagglutination-inhibition tests (HI). The percentage of positive sera was higher in area I (78%-69.2%) than in area II (63.1%-60.4%) for both viruses respectively. The coexistence of high titres to both H1N1- and H3N2-influenza virus became apparent in cold months simultaneously in each area, although influenza viruses circulated in the Spanish swine population for two years. Also this study suggests the possible circulation of A/Texas/1/77-like strains in Spain, results which have not been reported before. PMID:1320310

  6. Characterization of a novel oil-in-water emulsion adjuvant for swine influenza virus and Mycoplasma hyopneumoniae vaccines.

    PubMed

    Galliher-Beckley, A; Pappan, L K; Madera, Rachel; Burakova, Y; Waters, A; Nickles, M; Li, X; Nietfeld, J; Schlup, J R; Zhong, Q; McVey, S; Dritz, S S; Shi, J

    2015-06-01

    Vaccines consisting of subunit or inactivated bacteria/virus and potent adjuvants are widely used to control and prevent infectious diseases. Because inactivated and subunit antigens are often less antigenic than live microbes, a growing need exists for the development of new and improved vaccine adjuvants that can elicit rapid and long-lasting immunity. Here we describe the development and characterization of a novel oil-in-water emulsion, OW-14. OW-14 contains low-cost plant-based emulsifiers and was added to antigen at a ratio of 1:3 with simple hand mixing. OW-14 was stable for prolonged periods of time at temperatures ranging from 4 to 40°C and could be sterilized by autoclaving. Our results showed that OW-14 adjuvanted inactivated swine influenza viruses (SIV; H3N2 and H1N1) and Mycoplasma hyopneumoniae (M. hyo) vaccines could be safely administered to piglets in two doses, three weeks apart. Injection sites were monitored and no adverse reactions were observed. Vaccinated pigs developed high and prolonged antibody titers to both SIV and M. hyo. Interestingly, antibody titers were either comparable or greater than those produced by commercially available FluSure (SIV) or RespiSure (M. hyo) vaccines. We also found that OW-14 can induce high antibody responses in pigs that were vaccinated with a decreased antigen dose. This study provides direct evidence that we have developed an easy-to-use and low-cost emulsion that can act as a powerful adjuvant in two common types of swine vaccines.

  7. Characterization of a novel oil-in-water emulsion adjuvant for swine influenza virus and Mycoplasma hyopneumoniae vaccines.

    PubMed

    Galliher-Beckley, A; Pappan, L K; Madera, Rachel; Burakova, Y; Waters, A; Nickles, M; Li, X; Nietfeld, J; Schlup, J R; Zhong, Q; McVey, S; Dritz, S S; Shi, J

    2015-06-01

    Vaccines consisting of subunit or inactivated bacteria/virus and potent adjuvants are widely used to control and prevent infectious diseases. Because inactivated and subunit antigens are often less antigenic than live microbes, a growing need exists for the development of new and improved vaccine adjuvants that can elicit rapid and long-lasting immunity. Here we describe the development and characterization of a novel oil-in-water emulsion, OW-14. OW-14 contains low-cost plant-based emulsifiers and was added to antigen at a ratio of 1:3 with simple hand mixing. OW-14 was stable for prolonged periods of time at temperatures ranging from 4 to 40°C and could be sterilized by autoclaving. Our results showed that OW-14 adjuvanted inactivated swine influenza viruses (SIV; H3N2 and H1N1) and Mycoplasma hyopneumoniae (M. hyo) vaccines could be safely administered to piglets in two doses, three weeks apart. Injection sites were monitored and no adverse reactions were observed. Vaccinated pigs developed high and prolonged antibody titers to both SIV and M. hyo. Interestingly, antibody titers were either comparable or greater than those produced by commercially available FluSure (SIV) or RespiSure (M. hyo) vaccines. We also found that OW-14 can induce high antibody responses in pigs that were vaccinated with a decreased antigen dose. This study provides direct evidence that we have developed an easy-to-use and low-cost emulsion that can act as a powerful adjuvant in two common types of swine vaccines. PMID:25936722

  8. Molecular epidemiology study of swine influenza virus revealing a reassorted virus H1N1 in swine farms in Cuba.

    PubMed

    Pérez, Lester J; Perera, Carmen Laura; Coronado, Liani; Rios, Liliam; Vega, Armando; Frías, Maria T; Ganges, Llilianne; Núñez, José Ignacio; Díaz de Arce, Heidy

    2015-05-01

    In this report, we describe the emergence of reassorted H1N1 swine influenza virus, originated from a reassortment event between the H1N1 pandemic influenza virus (H1N1p/2009) and endemic swine influenza virus in Cuban swine population. In November 2010, a clinical respiratory outbreak was reported on a pig fattening farm in Cuba. Phylogenetic analysis showed that all the genes of one of the isolate obtained, with the exception of neuraminidase, belonged to the H1N1p/2009 cluster. This finding suggests that H1N1pdm has been established in swine and has become a reservoir of reassortment that may produce new viruses with both animal and public health risks. PMID:25745869

  9. Molecular epidemiology study of swine influenza virus revealing a reassorted virus H1N1 in swine farms in Cuba.

    PubMed

    Pérez, Lester J; Perera, Carmen Laura; Coronado, Liani; Rios, Liliam; Vega, Armando; Frías, Maria T; Ganges, Llilianne; Núñez, José Ignacio; Díaz de Arce, Heidy

    2015-05-01

    In this report, we describe the emergence of reassorted H1N1 swine influenza virus, originated from a reassortment event between the H1N1 pandemic influenza virus (H1N1p/2009) and endemic swine influenza virus in Cuban swine population. In November 2010, a clinical respiratory outbreak was reported on a pig fattening farm in Cuba. Phylogenetic analysis showed that all the genes of one of the isolate obtained, with the exception of neuraminidase, belonged to the H1N1p/2009 cluster. This finding suggests that H1N1pdm has been established in swine and has become a reservoir of reassortment that may produce new viruses with both animal and public health risks.

  10. 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

  11. Efficacy of Inactivated Swine Influenza Virus Vaccines Against the 2009 A/H1N1 Influenza Virus in Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gene constellation of the 2009 pandemic A/H1N1 virus is a unique combination from swine influenza A viruses (SIV) of North American and Eurasian lineages, but prior to April 2009 had never before been identified in swine or other species. Although its hemagglutinin gene is related to North Ameri...

  12. Efficacy of Inactivated Swine Influenza Virus Vaccines Against 2009 H1N1 Influenza Virus in Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. The gene constellation of the 2009 pandemic H1N1 virus is a unique combination from swine influenza A viruses (SIV) of North American and Eurasian lineages, but prior to April 2009 had never before been identified in swine or other species (1). Although its hemagglutinin gene is relat...

  13. Swine influenza virus vaccine research and technology: What does the future hold and what are our next steps?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine influenza represents a problem for the health of pigs and the economic health of the swine industry due to real and perceived public health risks. This is largely driven by the diversity of influenza A viruses (IAV) in swine herds. Antigenic drift (mutations) and shifts (reassortments) by in...

  14. Swine worker awareness and behavior regarding prevention of zoonotic influenza transmission.

    PubMed

    Rabinowitz, Peter; Fowler, Heather; Odofin, Lynda Osadepe; Messinger, Chelsea; Sparer, Judy; Vegso, Sally

    2013-01-01

    ABSTRACT A convenience survey of swine workers on large and small commercial farms in the Northeast and Midwest United States regarding zoonotic influenza awareness and precautions was conducted. Workers reported low levels of concern regarding the risk of contracting influenza from swine, and were generally not aware of national guidelines for influenza prevention. Use of personal protective equipment (PPE) varied by task, N95 respirator use was rare, and no workers were enrolled in respirator programs. Reported influenza vaccination coverage was greater than the national average in 2009-2010, but declined in 2010-2011. Workers on large farms were more likely to use PPE in some tasks and to report using more precautions when pigs appeared ill. Although reporting low levels of concern regarding zoonotic influenza and low adherence to national influenza guidelines, swine workers reported making task-based and risk-based decisions about use of PPE, suggesting opportunities for enhanced prevention of zoonotic disease transmission. PMID:24125045

  15. Swine worker awareness and behavior regarding prevention of zoonotic influenza transmission.

    PubMed

    Rabinowitz, Peter; Fowler, Heather; Odofin, Lynda Osadepe; Messinger, Chelsea; Sparer, Judy; Vegso, Sally

    2013-01-01

    ABSTRACT A convenience survey of swine workers on large and small commercial farms in the Northeast and Midwest United States regarding zoonotic influenza awareness and precautions was conducted. Workers reported low levels of concern regarding the risk of contracting influenza from swine, and were generally not aware of national guidelines for influenza prevention. Use of personal protective equipment (PPE) varied by task, N95 respirator use was rare, and no workers were enrolled in respirator programs. Reported influenza vaccination coverage was greater than the national average in 2009-2010, but declined in 2010-2011. Workers on large farms were more likely to use PPE in some tasks and to report using more precautions when pigs appeared ill. Although reporting low levels of concern regarding zoonotic influenza and low adherence to national influenza guidelines, swine workers reported making task-based and risk-based decisions about use of PPE, suggesting opportunities for enhanced prevention of zoonotic disease transmission.

  16. Cloned cDNA of A/swine/Iowa/15/1930 internal genes as a candidate backbone for reverse genetics vaccine against influenza A viruses

    PubMed Central

    Lekcharoensuk, Porntippa; Wiriyarat, Witthawat; Petcharat, Nuntawan; Lekcharoensuk, Chalermpol; Auewarakul, Prasert; Richt, Juergen A

    2012-01-01

    Reverse genetics viruses for influenza vaccine production usually utilize the internal genes of the egg-adapted A/Puerto Rico/8/34 (PR8) strain. This egg-adapted strain provides high production yield in embryonated eggs but does not necessarily give the best yield in mammalian cell culture. In order to generate a reverse genetics viral backbone that is well-adapted to high growth in mammalian cell culture, a swine influenza isolate (A/swine/Iowa/15/30 (H1N1) (rg1930) that was shown to give high yield in Madin-Darby Canine Kidney (MDCK) cells was used as the internal gene donor for reverse genetics plasmids. In this report, the internal genes from rg1930 were used for construction of reverse genetics viruses carrying a cleavage site-modified hemagglutinin (HA) gene and neuraminidase (NA) gene from a highly pathogenic H5N1 virus. The resulting virus (rg1930H5N1) was low pathogenic in vivo. Inactivated rg1930H5N1 vaccine completely protected chickens from morbidity and mortality after challenge with highly pathogenic H5N1. Protective immunity was obtained when chickens were immunized with an inactivated vaccine consisting of at least 29 HA units of the rg1930H5N1 virus. In comparison to the PR8-based reverse genetics viruses carrying the same HA and NA genes from an H5N1 virus, rg1930 based viruses yielded higher viral titers in MDCK and Vero cells. In addition, the reverse genetics derived H3N2 and H5N2 viruses with the rg1930 backbone replicated in MDCK cells better than the cognate viruses with the rgPR8 backbone. It is concluded that this newly established reverse genetics backbone system could serve as a candidate for a master donor strain for development of inactivated influenza vaccines in cell-based systems. PMID:22230579

  17. Current trends from the USDA influenza a virus in swine surveillance system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A U.S. national surveillance system for influenza A viruses (IAV) in swine was initiated in 2009 with increasing participation to the present day. The objectives are to monitor genetic evolution of IAV in swine, make isolates available for research, diagnostic reagents, and vaccine development throu...

  18. Connecting the dots between swine influenza A virus surveillance and vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Pathogenesis Studies of the 2009 Pandemic Influenza Virus and Pseudorabies Virus From Wild Pigs In Swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last ten years in the United States the epidemiology and ecology of swine flu and pseudorabies has been dynamic. Swine flu is caused by influenza A virus and the disease was first recognized in pigs concurrent with the 1918 Spanish flu pandemic in humans. Pigs displayed clinical signs simil...

  20. Introductions and evolution of human-origin seasonal influenza A viruses in multinational swine populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 influen...

  1. The genetic diversity of contemporary swine influenza A viruses in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Influenza A virus (IAV) is one of the most important respiratory pathogens of swine. It impacts mortality and causes significant financial losses through decreased production and the costs associated with vaccination and treatment. Further, due to the susceptibility of swine to transie...

  2. 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

  3. [Comparative study of the differential susceptibility of different cell lines to pandemic H1N1v influenza viruses and avian influenza, swine influenza, and human influenza viruses].

    PubMed

    Danilenko, D M; Smirnova, T D; Gudkova, T M; Eropkin, M Iu; Kiselev, O I

    2011-01-01

    The proliferation characteristics of influenza viruses of different origin were tested in various human and animal cell cultures. Pandemic H1N1v influenza and swine influenza viruses were shown to have a low infectious activity in virtually all the test lines. In spite of this, the replication of this group of viruses may be detected by de novo NP synthesis. These viruses are able to activate programmed cell death. Moreover, a low inoculative virus dose exerts a stimulating effect on cell proliferation in both suspension and monolayer cell lines.

  4. 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. PMID:26790939

  5. 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.

  6. The DoD Global, Laboratory-based, Influenza Surveillance Program: summary for the 2013-2014 influenza season.

    PubMed

    DeMarcus, Laurie S; Parms, Tiffany A; Thervil, Jeffrey W

    2016-03-01

    This report for the 2013-2014 influenza season summarizes the results of influenza surveillance carried out by the DoD Global, Laboratory-based, Influenza Surveillance Program, which is managed by the U.S. Air Force School of Aerospace Medicine Epidemiology Consult Service and Epidemiology Laboratory at Wright-Patterson Air Force Base, OH. Sentinel sites submitted 3,903 specimens for clinical diagnostic testing and 1,163 (29.8%) were positive for influenza virus. The predominant influenza subtype was influenza A(H1N1)pdm09, identified in 79.2% of all influenza-positive specimens. The other most common subtypes were influenza A(H3N2) (10.5%) and influenza B (10.1%). In August 2014, a human case of influenza A(H3N2) variant was identified in a patient with a history of exposure to swine. Adjusted vaccine effectiveness (VE) was calculated among 1,016 military dependents and retirees in the U.S. and was found to be 44.8% for all vaccine types. Uncertainties and other limitations associated with estimating VE are discussed. PMID:27030925

  7. The use of antiviral drugs for influenza: Guidance for practitioners 2012/2013.

    PubMed

    Aoki, Fred Y; Allen, Upton D; Stiver, H Grant; Evans, Gerald A

    2012-01-01

    The present article addresses the use of antiviral drugs in the management of seasonal influenza illness for the 2012/2013 season. It updates the previous document published in 2011 (1). Noteworthy guidance updates since 2011 include the following: Seasonal influenza in 2012/2013 is predicted to be caused by two human influenza A and one influenza B strain, all of which are anticipated to remain generally susceptible to oseltamivir.The predicted strains are A/California/7/2009 (H1N1) pdm09-like, A/Victoria/361/2011 (H3N2)-like and B/Wisconsin/1/2010-like (Yamagata lineage). All are included in the seasonal influenza vaccine and are susceptible to oseltamivir.Swine-variant H3N2v, which has rarely caused infection in humans exposed to infected swine within the past year in the United States, is susceptible to oseltamivir. It is not included in the current seasonal influenza vaccine.It is still considered that initiation of antiviral therapy more than 36 h to 48 h after onset of symptoms is beneficial in patients hospitalized with complicated influenza and severe illness.Oseltamivir continues to be recommended for the treatment of influenza in pregnant women.The use of antiviral drugs among measures to control outbreaks of influenza in closed facilities such as correctional institutions is now included in the present document.

  8. Interspecies interactions and potential Influenza A virus risk in small swine farms in Peru

    PubMed Central

    2012-01-01

    Background The recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health. The animal origins of the viruses confirmed the potential for interspecies transmission. Swine are hypothesized to be prime "mixing vessels" due to the dual receptivity of their trachea to human and avian strains. Additionally, avian and human influenza viruses have previously been isolated in swine. Therefore, understanding interspecies contact on smallholder swine farms and its potential role in the transmission of pathogens such as influenza virus is very important. Methods This qualitative study aimed to determine swine-associated interspecies contacts in two coastal areas of Peru. Direct observations were conducted at both small-scale confined and low-investment swine farms (n = 36) and in open areas where swine freely range during the day (n = 4). Interviews were also conducted with key stakeholders in swine farming. Results In both locations, the intermingling of swine and domestic birds was common. An unexpected contact with avian species was that swine were fed poultry mortality in 6/20 of the farms in Chancay. Human-swine contacts were common, with a higher frequency on the confined farms. Mixed farming of swine with chickens or ducks was observed in 36% of all farms. Human-avian interactions were less frequent overall. Use of adequate biosecurity and hygiene practices by farmers was suboptimal at both locations. Conclusions Close human-animal interaction, frequent interspecies contacts and suboptimal biosecurity and hygiene practices pose significant risks of interspecies influenza virus transmission. Farmers in small-scale swine production systems constitute a high-risk population and need to be recognized as key in preventing interspecies pathogen transfer. A two-pronged prevention approach, which offers educational activities for swine farmers about sound hygiene and biosecurity practices and

  9. Characterization of a porcine intestinal epithelial cell line for influenza virus production

    PubMed Central

    Sun, Zhi; Huber, Victor C.; McCormick, Kara; Kaushik, Radhey S.; Boon, Adrianus C. M.; Zhu, Longchao; Hause, Ben; Webby, Richard J.

    2012-01-01

    We have developed a porcine intestine epithelial cell line, designated SD-PJEC for the propagation of influenza viruses. The SD-PJEC cell line is a subclone of the IPEC-J2 cell line, which was originally derived from newborn piglet jejunum. Our results demonstrate that SD-PJEC is a cell line of epithelial origin that preferentially expresses receptors of oligosaccharides with Sia2-6Gal modification. This cell line is permissive to infection with human and swine influenza A viruses and some avian influenza viruses, but poorly support the growth of human-origin influenza B viruses. Propagation of swine-origin influenza viruses in these cells results in a rapid growth rate within the first 24 h post-infection and the titres ranged from 4 to 8 log10 TCID50 ml−1. The SD-PJEC cell line was further tested as a potential alternative cell line to Madin–Darby canine kidney (MDCK) cells in conjunction with 293T cells for rescue of swine-origin influenza viruses using the reverse genetics system. The recombinant viruses A/swine/North Carolina/18161/02 (H1N1) and A/swine/Texas/4199-2/98 (H3N2) were rescued with virus titres of 7 and 8.25 log10 TCID50 ml−1, respectively. The availability of this swine-specific cell line represents a more relevant substrate for studies and growth of swine-origin influenza viruses. PMID:22739061

  10. Cluster analysis of the origins of the new influenza A(H1N1) virus.

    PubMed

    Solovyov, A; Palacios, G; Briese, T; Lipkin, W I; Rabadan, R

    2009-05-28

    In March and April 2009, a new strain of influenza A(H1N1) virus has been isolated in Mexico and the United States. Since the initial reports more than 10,000 cases have been reported to the World Health Organization, all around the world. Several hundred isolates have already been sequenced and deposited in public databases. We have studied the genetics of the new strain and identified its closest relatives through a cluster analysis approach. We show that the new virus combines genetic information related to different swine influenza viruses. Segments PB2, PB1, PA, HA, NP and NS are related to swine H1N2 and H3N2 influenza viruses isolated in North America. Segments NA and M are related to swine influenza viruses isolated in Eurasia. PMID:19480812

  11. Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time reverse-transcription polymerase chain reaction and virus isolation.

    PubMed

    Goodell, Christa K; Zhang, Jianqiang; Strait, Erin; Harmon, Karen; Patnayak, Devi; Otterson, Tracy; Culhane, Marie; Christopher-Hennings, Jane; Clement, Travis; Leslie-Steen, Pamela; Hesse, Richard; Anderson, Joe; Skarbek, Kevin; Vincent, Amy; Kitikoon, Pravina; Swenson, Sabrina; Jenkins-Moore, Melinda; McGill, Jodi; Rauh, Rolf; Nelson, William; O'Connell, Catherine; Shah, Rohan; Wang, Chong; Main, Rodger; Zimmerman, Jeffrey J

    2016-01-01

    The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 assays based on real-time reverse-transcription polymerase chain reaction (rRT-PCR) and 7 assays based on virus isolation (VI). The OF specimens were inoculated with H1N1 or H3N2 IAV and serially diluted 10-fold (10(-1) to 10(-8)). Eight participating laboratories received 180 randomized OF samples (10 replicates × 8 dilutions × 2 IAV subtypes plus 20 IAV-negative samples) and performed the rRT-PCR and VI procedure(s) of their choice. Analysis of the results with a mixed-effect logistic-regression model identified dilution and assay as variables significant (P < 0.0001) for IAV detection in OF by rRT-PCR or VI. Virus subtype was not significant for IAV detection by either rRT-PCR (P = 0.457) or VI (P = 0.101). For rRT-PCR the cycle threshold (Ct) values increased consistently with dilution but varied widely. Therefore, it was not possible to predict VI success on the basis of Ct values. The success of VI was inversely related to the dilution of the sample; the assay was generally unsuccessful at lower virus concentrations. Successful swine health monitoring and disease surveillance require assays with consistent performance, but significant differences in reproducibility were observed among the assays evaluated.

  12. Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time reverse-transcription polymerase chain reaction and virus isolation

    PubMed Central

    Goodell, Christa K.; Zhang, Jianqiang; Strait, Erin; Harmon, Karen; Patnayak, Devi; Otterson, Tracy; Culhane, Marie; Christopher-Hennings, Jane; Clement, Travis; Leslie-Steen, Pamela; Hesse, Richard; Anderson, Joe; Skarbek, Kevin; Vincent, Amy; Kitikoon, Pravina; Swenson, Sabrina; Jenkins-Moore, Melinda; McGill, Jodi; Rauh, Rolf; Nelson, William; O’Connell, Catherine; Shah, Rohan; Wang, Chong; Main, Rodger; Zimmerman, Jeffrey J.

    2016-01-01

    The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 assays based on real-time reverse-transcription polymerase chain reaction (rRT-PCR) and 7 assays based on virus isolation (VI). The OF specimens were inoculated with H1N1 or H3N2 IAV and serially diluted 10-fold (10−1 to 10−8). Eight participating laboratories received 180 randomized OF samples (10 replicates × 8 dilutions × 2 IAV subtypes plus 20 IAV-negative samples) and performed the rRT-PCR and VI procedure(s) of their choice. Analysis of the results with a mixed-effect logistic-regression model identified dilution and assay as variables significant (P < 0.0001) for IAV detection in OF by rRT-PCR or VI. Virus subtype was not significant for IAV detection by either rRT-PCR (P = 0.457) or VI (P = 0.101). For rRT-PCR the cycle threshold (Ct) values increased consistently with dilution but varied widely. Therefore, it was not possible to predict VI success on the basis of Ct values. The success of VI was inversely related to the dilution of the sample; the assay was generally unsuccessful at lower virus concentrations. Successful swine health monitoring and disease surveillance require assays with consistent performance, but significant differences in reproducibility were observed among the assays evaluated. PMID:26733728

  13. Modified live virus vaccine induces a distinct immune response profile compared to inactivated influenza A virus vaccines in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic and antigenic diversity within H1 influenza A virus (IAV) subtypes circulating in swine is increasing. The need for cross-protective influenza vaccines in swine is necessary as the virus becomes more diverse. This study compared the humoral and cell-mediated immune response of modified live ...

  14. 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.

  15. 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. PMID:26476563

  16. Modifications in the polymerase genes of a swine-like triple-reassortant influenza virus to generate live attenuated vaccines against 2009 pandemic H1N1 viruses.

    PubMed

    Pena, Lindomar; Vincent, Amy L; Ye, Jianqiang; Ciacci-Zanella, Janice R; Angel, Matthew; Lorusso, Alessio; Gauger, Philip C; Janke, Bruce H; Loving, Crystal L; Perez, Daniel R

    2011-01-01

    On 11 June 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) virus is the predominant influenza virus strain in the human population. It has also crossed the species barriers and infected turkeys and swine in several countries. Thus, the development of a vaccine that is effective in multiple animal species is urgently needed. We have previously demonstrated that the introduction of temperature-sensitive mutations into the PB2 and PB1 genes of an avian H9N2 virus, combined with the insertion of a hemagglutinin (HA) tag in PB1, resulted in an attenuated (att) vaccine backbone for both chickens and mice. Because the new pandemic strain is a triple-reassortant (TR) virus, we chose to introduce the double attenuating modifications into a swine-like TR virus isolate, A/turkey/OH/313053/04 (H3N2) (ty/04), with the goal of producing live attenuated influenza vaccines (LAIV). This genetically modified backbone had impaired polymerase activity and restricted virus growth at elevated temperatures. In vivo characterization of two H1N1 vaccine candidates generated using the ty/04 att backbone demonstrated that this vaccine is highly attenuated in mice, as indicated by the absence of signs of disease, limited replication, and minimum histopathological alterations in the respiratory tract. A single immunization with the ty/04 att-based vaccines conferred complete protection against a lethal H1N1pdm virus infection in mice. More importantly, vaccination of pigs with a ty/04 att-H1N1 vaccine candidate resulted in sterilizing immunity upon an aggressive intratracheal challenge with the 2009 H1N1 pandemic virus. Our studies highlight the safety of the ty/04 att vaccine platform and its potential as a master donor strain for the generation of live attenuated vaccines for humans and livestock.

  17. 2012-2013 influenza update: hitting a rapidly moving target.

    PubMed

    Jin, Xian Wen; Mossad, Sherif Beniameen

    2012-11-01

    From the deadly 2009 influenza A H1N1 pandemic to the looming threat of bird flu H5N1, the recent outbreak of swine flu H3N2v at agriculture fairs, and the emergence of drug-resistant H1N1, we are constantly challenged by influenza viruses. Vaccination remains the main strategy for prevention. With the knowledge gained from past pandemics, an adequate vaccine supply, and an updated preventive strategy, we are in a better position to face the challenge. PMID:23125327

  18. 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

  19. 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.

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

    PubMed

    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. PMID:27350259

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

    PubMed

    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

    2016-06-28

    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.

  2. 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

  3. Antibodies against avian-like A (H1N1) swine influenza virus among swine farm residents in eastern China.

    PubMed

    Yin, Xiuchen; Yin, Xin; Rao, Baizhong; Xie, Chunfang; Zhang, Pengchao; Qi, Xian; Wei, Ping; Liu, Huili

    2014-04-01

    In 2007, the avian-like H1N1 virus (A/swine/Zhejiang/1/07) was first isolated in pigs in China. Recently, it was reported that a 3-year-old boy was infected with avian-like A (H1N1) swine influenza virus (SIV) in Jiangsu Province, China. To investigate the prevalence of avian-like A (H1N1) SIV infection among swine farm residents in eastern China, an active influenza surveillance program was conducted on swine farms in this region from May 21, 2010 through April 22, 2012. A total of 1,162 participants were enrolled, including 1,136 persons from 48 pig farms, as well as 26 pig farm veterinarians. A total of 10.7% and 7.8% swine farm residents were positive for antibodies against avian-like A (H1N1) SIV by HI and NT assay, respectively, using 40 as the cut-off antibody titer. Meanwhile, all the serum samples collected from a control of healthy city residents were negative against avian-like A (H1N1) SIV. As the difference in numbers of antibody positive samples between the swine farm residents and health city residents controls was statistically significant (P = 0.002), these data suggest that occupational exposure to pigs may increase swine farm residents' and veterinarians' risk of avian-like A (H1N1) SIV infection in eastern China. This study provides the first data on avian-like A (H1N1) SIV infections in humans in China; the potential for avian-like A (H1N1) SIV entering the human population should also be taken into consideration.

  4. An update on swine-origin influenza virus A/H1N1: a review.

    PubMed

    Schnitzler, Sebastian U; Schnitzler, Paul

    2009-12-01

    Influenza viruses cause annual epidemics and occasional pandemics that have claimed the lives of millions. The emergence of new strains will continue to pose challenges to public health and the scientific communities. The recent flu pandemic caused by a swine-origin influenza virus A/H1N1 (S-OIV) presents an opportunity to examine virulence factors, the spread of the infection and to prepare for major influenza outbreaks in the future. The virus contains a novel constellation of gene segments, the nearest known precursors being viruses found in swine and it probably arose through reassortment of two viruses of swine origin. Specific markers for virulence can be evaluated in the viral genome, PB1-F2 is a molecular marker of pathogenicity but is not present in the new S-OIV. While attention was focused on a threat of an avian influenza H5N1 pandemic emerging from Asia, a novel influenza virus of swine origin emerged in North America, and is now spreading worldwide. However, S-OIV demonstrates that even serotypes already encountered in past human pandemics may constitute new pandemic threats. There are concerns that this virus may mutate or reassort with existing influenza viruses giving rise to more transmissible or more pathogenic viruses. The 1918 Spanish flu pandemic virus was relatively mild in its first wave and acquired more virulence when it returned in the winter. Thus preparedness on a global scale against a potential more virulent strain is highly recommended. Most isolates of the new S-OIVs are susceptible to neuraminidase inhibitors, and currently a vaccine against the pandemic strain is being manufactured and will be available this fall. This review summarizes the current information on the new pandemic swine-origin influenza virus A/H1N1.

  5. Human swine influenza A [H1N1]: practical advice for clinicians early in the pandemic.

    PubMed

    Fitzgerald, Dominic A

    2009-09-01

    The influenza pandemic the world was waiting for may have arrived, but the early indications are that the first wave of human swine influenza A [H1N1], also referred to as H1N1 Mexico 09 or "swine flu", is highly transmissible but of no greater virulence than seasonal influenza to date. The new swine flu H1N1 virus is a mixture of avian, porcine and human influenza RNA. With twenty thousand confirmed cases worldwide and 117 deaths within 7 weeks of the first acknowledgement of a possible pandemic by Mexican and WHO experts, the mortality rate is less than 0.1% and the majority of deaths centred upon the origin of the epidemic in Mexico [83%]. Swine flu is thus far a relatively mild illness seen predominantly in those who are healthy and under 25 years of age, perhaps reflecting protection from previous human influenza exposure in older people. As the virus spreads internationally, border protection issues have surfaced and public health initiatives are being progressively rolled out to minimise the transmission. Vaccines are being developed which will be trialled in the coming months with a likely availability by August 2009, in time for the northern hemisphere autumn and winter. Vigilance without alarm appears to be the recommendation so far.

  6. In Vivo Validation of Predicted and Conserved T Cell Epitopes in a Swine Influenza Model.

    PubMed

    Gutiérrez, Andres H; Loving, Crystal; Moise, Leonard; Terry, Frances E; Brockmeier, Susan L; Hughes, Holly R; Martin, William D; De Groot, Anne S

    2016-01-01

    Swine influenza is a highly contagious respiratory viral infection in pigs that is responsible for significant financial losses to pig farmers annually. Current measures to protect herds from infection include: inactivated whole-virus vaccines, subunit vaccines, and alpha replicon-based vaccines. As is true for influenza vaccines for humans, these strategies do not provide broad protection against the diverse strains of influenza A virus (IAV) currently circulating in U.S. swine. Improved approaches to developing swine influenza vaccines are needed. Here, we used immunoinformatics tools to identify class I and II T cell epitopes highly conserved in seven representative strains of IAV in U.S. swine and predicted to bind to Swine Leukocyte Antigen (SLA) alleles prevalent in commercial swine. Epitope-specific interferon-gamma (IFNγ) recall responses to pooled peptides and whole virus were detected in pigs immunized with multi-epitope plasmid DNA vaccines encoding strings of class I and II putative epitopes. In a retrospective analysis of the IFNγ responses to individual peptides compared to predictions specific to the SLA alleles of cohort pigs, we evaluated the predictive performance of PigMatrix and demonstrated its ability to distinguish non-immunogenic from immunogenic peptides and to identify promiscuous class II epitopes. Overall, this study confirms the capacity of PigMatrix to predict immunogenic T cell epitopes and demonstrate its potential for use in the design of epitope-driven vaccines for swine. Additional studies that match the SLA haplotype of animals with the study epitopes will be required to evaluate the degree of immune protection conferred by epitope-driven DNA vaccines in pigs. PMID:27411061

  7. In Vivo Validation of Predicted and Conserved T Cell Epitopes in a Swine Influenza Model

    PubMed Central

    Gutiérrez, Andres H.; Loving, Crystal; Moise, Leonard; Terry, Frances E.; Brockmeier, Susan L.; Hughes, Holly R.; Martin, William D.; De Groot, Anne S.

    2016-01-01

    Swine influenza is a highly contagious respiratory viral infection in pigs that is responsible for significant financial losses to pig farmers annually. Current measures to protect herds from infection include: inactivated whole-virus vaccines, subunit vaccines, and alpha replicon-based vaccines. As is true for influenza vaccines for humans, these strategies do not provide broad protection against the diverse strains of influenza A virus (IAV) currently circulating in U.S. swine. Improved approaches to developing swine influenza vaccines are needed. Here, we used immunoinformatics tools to identify class I and II T cell epitopes highly conserved in seven representative strains of IAV in U.S. swine and predicted to bind to Swine Leukocyte Antigen (SLA) alleles prevalent in commercial swine. Epitope-specific interferon-gamma (IFNγ) recall responses to pooled peptides and whole virus were detected in pigs immunized with multi-epitope plasmid DNA vaccines encoding strings of class I and II putative epitopes. In a retrospective analysis of the IFNγ responses to individual peptides compared to predictions specific to the SLA alleles of cohort pigs, we evaluated the predictive performance of PigMatrix and demonstrated its ability to distinguish non-immunogenic from immunogenic peptides and to identify promiscuous class II epitopes. Overall, this study confirms the capacity of PigMatrix to predict immunogenic T cell epitopes and demonstrate its potential for use in the design of epitope-driven vaccines for swine. Additional studies that match the SLA haplotype of animals with the study epitopes will be required to evaluate the degree of immune protection conferred by epitope-driven DNA vaccines in pigs. PMID:27411061

  8. Novel swine-origin influenza A virus in humans: another pandemic knocking at the door.

    PubMed

    Michaelis, Martin; Doerr, Hans Wilhem; Cinatl, Jindrich

    2009-08-01

    Influenza A viruses represent a continuous pandemic threat. In April 2009, a novel influenza A virus, the so-called swine-origin influenza A (H1N1) virus (S-OIV), was identified in Mexico. Although S-OIV originates from triple-reassortant swine influenza A (H1) that has been circulating in North American pig herds since the end of the 1990s, S-OIV is readily transmitted between humans but is not epidemic in pigs. After its discovery, S-OIV rapidly spread throughout the world within few weeks. In this review, we sum up the current situation and put it into the context of the current state of knowledge of influenza and influenza pandemics. Some indications suggest that a pandemic may be mild but even "mild" pandemics can result in millions of deaths. However, no reasonable forecasts how this pandemic may develop can be made at this time. Despite stockpiling by many countries and WHO, antiviral drugs will be limited in case of pandemic and resistances may emerge. Effective vaccines are regarded to be crucial for the control of influenza pandemics. However, production capacities are restricted and development/production of a S-OIV vaccine will interfere with manufacturing of seasonal influenza vaccines. The authors are convinced that S-OIV should be taken seriously as pandemic threat and underestimation of the menace by S-OIV to be by far more dangerous than its overestimation.

  9. THE INCIDENCE OF NEUTRALIZING ANTIBODIES FOR SWINE INFLUENZA VIRUS IN THE SERA OF HUMAN BEINGS OF DIFFERENT AGES

    PubMed Central

    Shope, Richard E.

    1936-01-01

    Sera from a very high proportion of the human adults and new-born infants studied neutralized swine influenza virus; sera from children below the age of 12 years seldom exerted such an effect. The results of neutralization experiments with human sera and the virus of swine influenza have been compared with the outcome of similar tests with the virus of human influenza, and it seems evident that the presence of antibodies neutralizing swine influenza virus cannot be deemed the result of repeated exposures to the current human type of virus. From the known history of swine influenza and the similarity of its etiologic virus to that obtained from man it seems likely that the virus of swine influenza is the surviving prototype of the agent primarily responsible for the great human pandemic of 1918, as Laidlaw has already suggested. The presence in human sera of antibodies neutralizing swine influenza virus is believed to indicate a previous immunizing exposure to, or infection with, an influenza virus of the 1918 type. PMID:19870496

  10. Human-Like H1 (Delta-Cluster) Swine Influenza Virus (SIV) Can Efficiently Replicate, Transmit, Cause Lung Pathology and Induce Humoral Immune Responses in the Swine Host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. Genomic characterization of recently identified H1 influenza A viruses demonstrated the viruses were triple reassortants with an internal gene constellation similar to contemporary U.S. swine influenza virus (SIV) but hemagglutinin (HA) and neuraminidase (NA) most similar to human seas...

  11. 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.

  12. Comparison of Humoral and Cellular Immune Responses to Inactivated Swine Influenza Virus Vaccine in Weaned Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humoral and cellular immune responses to inactivated swine influenza virus (SIV) vaccine were evaluated and compared. Fifty 3-week-old weaned pigs from a herd free of SIV and PRRSV were randomly divided into the non-vaccinated control group and vaccinated group containing 25 pigs each. Pigs were va...

  13. Comparison of Humoral and Cellular Immune Responses to Inactivated Swine Influenza Virus Vaccine in Weaned Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose: To evaluate and compare humoral and cellular immune responses to inactivated swine influenza virus (SIV) vaccine. Methods: Fifty 3-week-old weaned pigs from a herd free of SIV and PRRSV were randomly divided into the non-vaccinated control group and vaccinated group containing 25 pigs each....

  14. Long-term evolution and transmission dynamics of swine influenza A virus.

    PubMed

    Vijaykrishna, Dhanasekaran; Smith, Gavin J D; Pybus, Oliver G; Zhu, Huachen; Bhatt, Samir; Poon, Leo L M; Riley, Steven; Bahl, Justin; Ma, Siu K; Cheung, Chung L; Perera, Ranawaka A P M; Chen, Honglin; Shortridge, Kennedy F; Webby, Richard J; Webster, Robert G; Guan, Yi; Peiris, J S Malik

    2011-05-26

    Swine influenza A viruses (SwIV) cause significant economic losses in animal husbandry as well as instances of human disease and occasionally give rise to human pandemics, including that caused by the H1N1/2009 virus. The lack of systematic and longitudinal influenza surveillance in pigs has hampered attempts to reconstruct the origins of this pandemic. Most existing swine data were derived from opportunistic samples collected from diseased pigs in disparate geographical regions, not from prospective studies in defined locations, hence the evolutionary and transmission dynamics of SwIV are poorly understood. Here we quantify the epidemiological, genetic and antigenic dynamics of SwIV in Hong Kong using a data set of more than 650 SwIV isolates and more than 800 swine sera from 12 years of systematic surveillance in this region, supplemented with data stretching back 34 years. Intercontinental virus movement has led to reassortment and lineage replacement, creating an antigenically and genetically diverse virus population whose dynamics are quantitatively different from those previously observed for human influenza viruses. Our findings indicate that increased antigenic drift is associated with reassortment events and offer insights into the emergence of influenza viruses with epidemic potential in swine and humans.

  15. DNA vaccination elicits protective immune responses against pandemic and classic swine influenza viruses in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 public health threat, highlighted by the possibility that the 2009 H1N1 pandemic strain emerged from r...

  16. Tmprss2 is essential for influenza H1N1 virus pathogenesis in mice.

    PubMed

    Hatesuer, Bastian; Bertram, Stephanie; Mehnert, Nora; Bahgat, Mahmoud M; Nelson, Peter S; Pöhlmann, Stefan; Pöhlman, Stefan; Schughart, Klaus

    2013-01-01

    Annual influenza epidemics and occasional pandemics pose a severe threat to human health. Host cell factors required for viral spread but not for cellular survival are attractive targets for novel approaches to antiviral intervention. The cleavage activation of the influenza virus hemagglutinin (HA) by host cell proteases is essential for viral infectivity. However, it is unknown which proteases activate influenza viruses in mammals. Several candidates have been identified in cell culture studies, leading to the concept that influenza viruses can employ multiple enzymes to ensure their cleavage activation in the host. Here, we show that deletion of a single HA-activating protease gene, Tmprss2, in mice inhibits spread of mono-basic H1N1 influenza viruses, including the pandemic 2009 swine influenza virus. Lung pathology was strongly reduced and mutant mice were protected from weight loss, death and impairment of lung function. Also, after infection with mono-basic H3N2 influenza A virus body weight loss and survival was less severe in Tmprss2 mutant compared to wild type mice. As expected, Tmprss2-deficient mice were not protected from viral spread and pathology after infection with multi-basic H7N7 influenza A virus. In conclusion, these results identify TMPRSS2 as a host cell factor essential for viral spread and pathogenesis of mono-basic H1N1 and H3N2 influenza A viruses. PMID:24348248

  17. Dynamics of virus shedding and antibody responses in influenza A virus-infected feral swine.

    PubMed

    Sun, Hailiang; Cunningham, Fred L; Harris, Jillian; Xu, Yifei; Long, Li-Ping; Hanson-Dorr, Katie; Baroch, John A; Fioranelli, Paul; Lutman, Mark W; Li, Tao; Pedersen, Kerri; Schmit, Brandon S; Cooley, Jim; Lin, Xiaoxu; Jarman, Richard G; DeLiberto, Thomas J; Wan, Xiu-Feng

    2015-09-01

    Given their free-ranging habits, feral swine could serve as reservoirs or spatially dynamic 'mixing vessels' for influenza A virus (IAV). To better understand virus shedding patterns and antibody response dynamics in the context of IAV surveillance amongst feral swine, we used IAV of feral swine origin to perform infection experiments. The virus was highly infectious and transmissible in feral swine, and virus shedding patterns and antibody response dynamics were similar to those in domestic swine. In the virus-inoculated and sentinel groups, virus shedding lasted ≤ 6 and ≤ 9 days, respectively. Antibody titres in inoculated swine peaked at 1 : 840 on day 11 post-inoculation (p.i.), remained there until 21 days p.i. and dropped to < 1 : 220 at 42 days p.i. Genomic sequencing identified changes in wildtype (WT) viruses and isolates from sentinel swine, most notably an amino acid divergence in nucleoprotein position 473. Using data from cell culture as a benchmark, sensitivity and specificity of a matrix gene-based quantitative reverse transcription-PCR method using nasal swab samples for detection of IAV in feral swine were 78.9 and 78.1 %, respectively. Using data from haemagglutination inhibition assays as a benchmark, sensitivity and specificity of an ELISA for detection of IAV-specific antibody were 95.4 and 95.0 %, respectively. Serological surveillance from 2009 to 2014 showed that ∼7.58 % of feral swine in the USA were positive for IAV. Our findings confirm the susceptibility of IAV infection and the high transmission ability of IAV amongst feral swine, and also suggest the need for continued surveillance of IAVs in feral swine populations. PMID:26297148

  18. Dynamics of virus shedding and antibody responses in influenza A virus-infected feral swine

    PubMed Central

    Sun, Hailiang; Cunningham, Fred L.; Harris, Jillian; Xu, Yifei; Long, Li-Ping; Hanson-Dorr, Katie; Baroch, John A.; Fioranelli, Paul; Lutman, Mark W.; Li, Tao; Pedersen, Kerri; Schmit, Brandon S.; Cooley, Jim; Lin, Xiaoxu; Jarman, Richard G.; DeLiberto, Thomas J.

    2015-01-01

    Given their free-ranging habits, feral swine could serve as reservoirs or spatially dynamic ‘mixing vessels’ for influenza A virus (IAV). To better understand virus shedding patterns and antibody response dynamics in the context of IAV surveillance amongst feral swine, we used IAV of feral swine origin to perform infection experiments. The virus was highly infectious and transmissible in feral swine, and virus shedding patterns and antibody response dynamics were similar to those in domestic swine. In the virus-inoculated and sentinel groups, virus shedding lasted ≤ 6 and ≤ 9 days, respectively. Antibody titres in inoculated swine peaked at 1 : 840 on day 11 post-inoculation (p.i.), remained there until 21 days p.i. and dropped to < 1 : 220 at 42 days p.i. Genomic sequencing identified changes in wildtype (WT) viruses and isolates from sentinel swine, most notably an amino acid divergence in nucleoprotein position 473. Using data from cell culture as a benchmark, sensitivity and specificity of a matrix gene-based quantitative reverse transcription-PCR method using nasal swab samples for detection of IAV in feral swine were 78.9 and 78.1 %, respectively. Using data from haemagglutination inhibition assays as a benchmark, sensitivity and specificity of an ELISA for detection of IAV-specific antibody were 95.4 and 95.0 %, respectively. Serological surveillance from 2009 to 2014 showed that ∼7.58 % of feral swine in the USA were positive for IAV. Our findings confirm the susceptibility of IAV infection and the high transmission ability of IAV amongst feral swine, and also suggest the need for continued surveillance of IAVs in feral swine populations. PMID:26297148

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Immune and inflammatory response in pigs during acute influenza caused by H1N1 swine influenza virus.

    PubMed

    Pomorska-Mól, Małgorzata; Markowska-Daniel, Iwona; Kwit, Krzysztof; Czyżewska, Ewelina; Dors, Arkadiusz; Rachubik, Jarosław; Pejsak, Zygmunt

    2014-10-01

    Swine influenza (SI) is an acute respiratory disease of pigs, caused by swine influenza virus (SIV). Little is known about the inflammatory response in the lung during acute SI and its correlation with clinical signs or lung pathology. Moreover, until now there has been a limited amount of data available on the relationship between the concentrations of pro- and anti-inflammatory cytokines in the lungs and the serum concentration of acute-phase proteins (APPs) in SIV-infected pigs. In the present study, the porcine inflammatory and immune responses during acute influenza caused by H1N1 SIV (SwH1N1) were studied. Nine pigs were infected intratracheally, and five served as controls. Antibodies against SIV were measured by haemagglutination inhibition assay, and the influenza-virus-specific T-cell response was measured using a proliferation assay. C-reactive protein (CRP), haptoglobin (Hp), serum amyloid A (SAA), and pig major acute-phase protein (Pig-MAP) the concentrations in serum and concentration of IL-1β, IL-6, IL-8, IL-10, TNF-α and IFN-γ in lung tissues were measured using commercial ELISAs.

  1. H1N1 (Originally Referred to As Swine Flu)

    MedlinePlus

    ... Changes H7N9 H3N2v H1N1 - Swine Flu H5N1 - Avian/Bird Flu Planning & Preparedness Business Planning Community Planning School ... Changes H7N9 H3N2v H1N1 - Swine Flu H5N1 - Avian/Bird Flu H1N1 - originally referred to as Swine Flu ...

  2. 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.

  3. 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

  4. The Inability to Screen Exhibition Swine for Influenza A Virus Using Body Temperature.

    PubMed

    Bowman, A S; Nolting, J M; Workman, J D; Cooper, M; Fisher, A E; Marsh, B; Forshey, T

    2016-02-01

    Agricultural fairs create an unconventional animal-human interface that has been associated with swine-to-human transmission of influenza A virus (IAV) in recent years. Early detection of IAV-infected pigs at agricultural fairs would allow veterinarians to better protect swine and human health during these swine exhibitions. This study assessed the use of swine body temperature measurement, recorded by infrared and rectal thermometers, as a practical method to detect IAV-infected swine at agricultural fairs. In our first objective, infrared thermometers were used to record the body surface temperature of 1,092 pigs at the time of IAV nasal swab collection at the end of the exhibition period of 55 agricultural fairs. IAV was recovered from 212 (19.4%) pigs, and the difference in mean infrared body temperature measurement of IAV-positive and IAV-negative pigs was 0.83°C. In a second objective, snout wipes were collected from 1,948 pigs immediately prior to the unloading of the animals at a single large swine exhibition. Concurrent to the snout wipe collection, owners took the rectal temperatures of his/her pigs. In this case, 47 (2.4%) pigs tested positive for IAV before they entered the swine barn. The mean rectal temperatures differed by only 0.19°C between IAV-positive and IAV-negative pigs. The low prevalence of IAV among the pigs upon entry to the fair in the second objective provides evidence that limiting intraspecies spread of IAV during the fairs will likely have significant impacts on the zoonotic transmission. However, in both objectives, the high degree of similarity in the body temperature measurements between the IAV-positive and IAV-negative pigs made it impossible to set a diagnostically meaningful cut point to differentiate IAV status of the individual animals. Unfortunately, body temperature measurement cannot be used to accurately screen exhibition swine for IAV.

  5. Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated two US swine influenza virus (SIV) isolates, A/Swine/Iowa/15/1930 H1N1 (IA30) and A/Swine/Minnesota/00194/2003 H1N2 (MN03), with substantial genetic variation in the HA gene and failure to cross-react in the hemagglutination inhibition (HI) assay, in an in vivo vaccination and challenge...

  6. Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time, reverse transcription polymerase chain reaction (rRT-PCR) and virus isolation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 real-time, reverse transcription polymerase chain reaction (rRT-PCR) and 7 virus isolation (VI) assays. To conduct the study, OF was inoculated with H1N1 or H3N2 IAV and serially 10-fold d...

  7. Reassortment events among swine influenza A viruses in China: implications for the origin of the 2009 influenza pandemic.

    PubMed

    Lam, Tommy Tsan-Yuk; Zhu, Huachen; Wang, Jia; Smith, David K; Holmes, Edward C; Webster, Robert G; Webby, Richard; Peiris, Joseph M; Guan, Yi

    2011-10-01

    That pigs may play a pivotal role in the emergence of pandemic influenza was indicated by the recent H1N1/2009 human pandemic, likely caused by a reassortant between viruses of the American triple-reassortant (TR) and Eurasian avian-like (EA) swine influenza lineages. As China has the largest human and pig populations in the world and is the only place where both TR and EA viruses have been reported to cocirculate, it is potentially the source of the H1N1/2009 pandemic virus. To examine this, the genome sequences of 405 swine influenza viruses from China were analyzed. Thirty-six TR and EA reassortant viruses were identified before and after the occurrence of the pandemic. Several of these TR-EA reassortant viruses had genotypes with most segments having the same lineage origin as the segments of the H1N1/2009 pandemic virus. However, these viruses were generated from independent reassortment events throughout our survey period and were not associated with the current pandemic. One TR-EA reassortant, which is least similar to the pandemic virus, has persisted since 2007, while all the other variants appear to be transient. Despite frequent reassortment events between TR and EA lineage viruses in China, evidence for the genesis of the 2009 pandemic virus in pigs in this region is still absent.

  8. 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.

  9. Pandemic swine influenza virus (H1N1): A threatening evolution.

    PubMed

    Khanna, Madhu; Kumar, Binod; Gupta, Neha; Kumar, Prashant; Gupta, Ankit; Vijayan, V K; Kaur, Harpreet

    2009-12-01

    "Survival of the fittest" is an old axiom laid down by the great evolutionist Charles Darwin and microorganisms seem to have exploited this statement to a great extent. The ability of viruses to adapt themselves to the changing environment has made it possible to inhabit itself in this vast world for the past millions of years. Experts are well versed with the fact that influenza viruses have the capability to trade genetic components from one to the other within animal and human population. In mid April 2009, the Centers for Disease Control and Prevention and the World Health Organization had recognized a dramatic increase in number of influenza cases. These current 2009 infections were found to be caused by a new strain of influenza type A H1N1 virus which is a re-assortment of several strains of influenza viruses commonly infecting human, avian, and swine population. This evolution is quite dependent on swine population which acts as a main reservoir for the reassortment event in virus. With the current rate of progress and the efforts of heath authorities worldwide, we have still not lost the race against fighting this virus. This article gives an insight to the probable source of origin and the evolutionary progress it has gone through that makes it a potential threat in the future, the current scenario and the possible measures that may be explored to further strengthen the war against pandemic.

  10. Phylogenetic evolution of swine-origin human influenza virus: a pandemic H1N1 2009.

    PubMed

    Kowalczyk, A; Markowska-Daniel, I

    2010-01-01

    The knowledge of the genome constellation in pandemic influenza A virus H1N1 2009 from different countries and different hosts is valuable for monitoring and understanding of the evolution and migration of these strains. The complete genome sequences of selected worldwide distributed influenza A viruses are publicly available and there have been few longitudinal genome studies of human, avian and swine influenza A viruses. All possible to download SIV sequences of influenza A viruses available at GISAID Platform (Global Initiative on Sharing Avian Influenza Data) were analyzed firstly through the web servers of the Influenza Virus Resource in NCBI. Phylogenetic study of circulating human pandemic H1N1 virus indicated that the new variant possesses a distinctive evolutionary trait. There is no one way the pandemic H1N1 have acquired new genes from other distinguishable viruses circulating recently in local human, pig or domestic poultry populations from various geographic regions. The extensive genetic diversity among whole segments present in pandemic H1N1 genome suggests that multiple introduction of virus have taken place during the period 1999-2009. The initial interspecies transmission could have occurred in the long-range past and after it the reassortants steps lead to three lineages: classical SIV prevalent in the North America, avian-like SIV in Europe and avian-like related SIV in Asia. This analysis contributes to the evidence that pigs are not the only hosts playing the role of "mixing vessel", as it was suggested for many years.

  11. Emergence and characterisation of pandemic H1N1 influenza viruses in Hungarian swine herds.

    PubMed

    Bálint, Adám; Kiss, István; Bányai, Krisztián; Biksi, Imre; Szentpáli-Gavallér, Katalin; Magyar, Tibor; Jankovics, István; Rózsa, Mónika; Szalai, Bálint; Takács, Mária; Tóth, Adám György; Dán, Adám

    2013-03-01

    In 2010, two novel porcine H1N1 influenza viruses were isolated from pigs with influenza-like illness in Hungarian swine herds. Sequence and phylogenetic analysis of these strains revealed that they shared molecular features with the pandemic H1N1 influenza virus strains, which emerged globally during 2009. The PB2, HA and NA genes contained unique amino acid changes compared to the available new H1N1 influenza virus sequences of pig origin. Furthermore, the investigated strains could be separated with respect to parallel amino acid substitutions affecting the polymerase genes (PB2, PB1 and PA) and the nucleoprotein (NP) gene, supporting the proposed complementarities between these proteins, all required for the viral fitness. Molecular characterisation of two Hungarian human pandemic H1N1 isolates was also performed, so that we could compare contemporaneous strains of different host species origins. Shared molecular motifs in various genes of animal and human influenza strains suggested that the Hungarian porcine strains could have originated from humans through direct interspecies transmission. This study is among the few that support the natural human-to-pig transmission of the pandemic H1N1 influenza virus.

  12. Novel swine-origin influenza virus A (H1N1): the first pandemic of the 21st century.

    PubMed

    Chang, Luan-Yin; Shih, Shin-Ru; Shao, Pei-Lan; Huang, Daniel Tsung-Ning; Huang, Li-Min

    2009-07-01

    An influenza epidemic was detected in April 2009 at the border between the United States and Mexico. The virus was identified soon after to be a swine-origin influenza virus A (S-OIV A) (H1N1). This virus has an HA gene that is derived from the 1918 swine influenza virus and other genes from human, avian, and Eurasian swine influenza viruses. Clinically, it behaves similarly to seasonal influenza. The only differentiating characteristics are vomiting and diarrhea in a quarter of infected patients, which are rare in seasonal influenza. On June 11, 2009, the World Health Organization declared the first pandemic of the 21st century, caused by S-OIV A (H1N1). Vaccination is the only way to dampen this pandemic. Many questions await answers, including the clinical impact of the pandemic, optimal doses of vaccine, and the future destiny of the virus. A breakthrough in vaccinology against influenza is needed to address the recurring influenza pandemic.

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

    PubMed Central

    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.

    2010-01-01

    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. PMID:21074235

  14. "Trivalent influenza vaccination of healthy adults 3 years after the onset of swine-origin H1N1 pandemic: restricted immunogenicity of the new A/H1N1v constituent?".

    PubMed

    Allwinn, R; Bickel, M; Lassmann, C; Wicker, S; Friedrichs, I

    2013-04-01

    Influenza vaccination is advised annually to reduce the burden of influenza disease. For sufficient vaccine campaigns also a continuous adoption of influenza vaccines are necessary, due to particularly high genetic variability of influenza A virus. Therefore, we evaluate the effectiveness of the trivalent influenza vaccine 2010/2011, against influenza A (H1N1, H3N2) and influenza B. Immune response was investigated in paired sera from 92 healthcare workers with the hemagglutination inhibition assay (HI). Protective antibody levels (HI titer ≥40) were found after vaccination for influenza A/California/07/2009(H1N1): 84.71 % [GMT: 115.34]; for influenza A/Perth/16/2009(H3N2): 94.94 % [GMT: 268.47] and for influenza B/Brisbane/60/2008: 96.20 % [GMT: 176.83]; matching with the currently circulating virus strains. However, the highest seroprevalence rate was found against influenza B; pre- and post-vaccination titers as well, which may be due to comparatively high virus preservation. Remarkable, lowest seropositivity was seen against H1N1. Despite the significant titer rise, sufficient H1N1 herd immunity was still not achieved. It can be assumed that a high influenza A herd immunity may be a requirement for a successful booster vaccination.

  15. Predicting Hotspots for Influenza Virus Reassortment

    PubMed Central

    Gilbert, Marius; Martin, Vincent; Cappelle, Julien; Hosseini, Parviez; Njabo, Kevin Y.; Abdel Aziz, Soad; Xiao, Xiangming; Daszak, Peter; Smith, Thomas B.

    2013-01-01

    The 1957 and 1968 influenza pandemics, each of which killed ≈1 million persons, arose through reassortment events. Influenza virus in humans and domestic animals could reassort and cause another pandemic. To identify geographic areas where agricultural production systems are conducive to reassortment, we fitted multivariate regression models to surveillance data on influenza A virus subtype H5N1 among poultry in China and Egypt and subtype H3N2 among humans. We then applied the models across Asia and Egypt to predict where subtype H3N2 from humans and subtype H5N1 from birds overlap; this overlap serves as a proxy for co-infection and in vivo reassortment. For Asia, we refined the prioritization by identifying areas that also have high swine density. Potential geographic foci of reassortment include the northern plains of India, coastal and central provinces of China, the western Korean Peninsula and southwestern Japan in Asia, and the Nile Delta in Egypt. PMID:23628436

  16. Swine influenza - need for global surveillance and improved vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surveillance for influenza A viruses (IAV) circulating in pigs and other non-human mammals has been chronically underfunded and virtually nonexistent in many areas of the world. In March-April 2009, a novel pandemic H1N1 emerged and demonstrated in a very public forum the paucity of data on influenz...

  17. A brief introduction to influenza A virus in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A viruses (IAV) of the Orthomyxoviridae virus family cause one of the most important respiratory diseases in pigs as well as humans. Repeated outbreaks and rapid spread of genetically and antigenically distinct IAVs represent a considerable challenge for animal production and public health...

  18. Antibody secreting cell assay for influenza A virus in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An ELISPOT assay to enumerate B-cells producing antibodies specific to a given antigen, also known as an antibody secreting cell (ASC) assay, was adapted to detect B-cells specific for influenza A virus (IAV). The assay is performed ex vivo and enumerates ASC at a single cell level. A simple ASC det...

  19. Analysis of the influenza virus gene pool of avian species from southern China.

    PubMed

    Lin, Y P; Shu, L L; Wright, S; Bean, W J; Sharp, G B; Shortridge, K F; Webster, R G

    1994-02-01

    Although Southern China has been considered the epicenter of human influenza pandemics, little is known about the genetic composition of influenza viruses in lower mammals or birds in that region. To provide information on the molecular epidemiology of these viruses, we used dot blot hybridization and phylogenetic methods to study the internal genes (PB1, PB2, PA, NP, M, and NS) of 106 avian influenza A viruses isolated from a total of 11,798 domestic ducks, chickens, and geese raised in Southern China including Hong Kong. All 636 genes examined were characteristic of avian influenza viruses; no human or swine influenza genes were detected. Thus, influenza virus reassortants do not appear to be maintained in the domesticated birds of Southeast Asia, eliminating opportunities for further gene reassortment. Phylogenetic analysis showed that the internal genes of these viruses belong to the Eurasian avian lineage, supporting geographical separation of the major avian lineages. The PB1 genes were most similar to A/Singapore/57 (H2N2) and Hong Kong (H3N2) viral genes, supporting an avian origin for the recent human H2N2 and H3N2 pandemic strains. The majority of internal genes from avian influenza viruses in Southern China belong to the Eurasian lineage and are similar to viruses that have recently been transmitted to humans, swine, and horses. This study provides evidence that the transmission of avian influenza viruses and their genes to other species is unidirectional and that the transmission of mammalian influenza virus strains to domestic poultry is probably not a factor in the generation of new pandemic strains.

  20. 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.

  1. Reflections on New York City's 1947 Smallpox Vaccination Program and Its 1976 Swine Influenza Immunization Program.

    PubMed

    Imperato, Pascal James

    2015-06-01

    In 1947, a smallpox outbreak occurred in New York City with a total of twelve cases and two deaths. In order to contain this outbreak, the New York City Department of Health launched a mass immunization campaign that over a period of some 60 days vaccinated 6.35 million people. This article examines in detail the epidemiology of this outbreak and the measures employed to contain it. In 1976, a swine influenza strain was isolated among a few recruits at a US Army training camp at Fort Dix, New Jersey. It was concluded at the time that this virus possibly represented a re-appearance of the 1918 influenza pandemic influenza strain. As a result, a mass national immunization program was launched by the federal government. From its inception, the program encountered a myriad of challenges ranging from doubts that it was even necessary to the development of Guillain-Barré paralysis among some vaccine recipients. This paper examines the planning for and implementation of the swine flu immunization program in New York City. It also compares it to the smallpox vaccination program of 1947. Despite equivalent financial and personnel resources, leadership and organizational skills, the 1976 program only immunized approximately a tenth of the number of New York City residents vaccinated in 1947. The reasons for these marked differences in outcomes are discussed in detail.

  2. Tissue tropism of swine influenza viruses and reassortants in ex vivo cultures of the human respiratory tract and conjunctiva.

    PubMed

    Chan, Renee W Y; Kang, Sara S R; Yen, Hui-Ling; Li, Alan C L; Tang, Lynsia L S; Yu, Wendy C L; Yuen, Kit M; Chan, Icarus W W; Wong, Diana D Y; Lai, Wico W; Kwong, Dora L W; Sihoe, Alan D L; Poon, Leo L M; Guan, Yi; Nicholls, John M; Peiris, J S Malik; Chan, Michael C W

    2011-11-01

    The 2009 pandemic influenza H1N1 (H1N1pdm) virus was generated by reassortment of swine influenza viruses of different lineages. This was the first influenza pandemic to emerge in over 4 decades and the first to occur after the realization that influenza pandemics arise from influenza viruses of animals. In order to understand the biological determinants of pandemic emergence, it is relevant to compare the tropism of different lineages of swine influenza viruses and reassortants derived from them with that of 2009 pandemic H1N1 (H1N1pdm) and seasonal influenza H1N1 viruses in ex vivo cultures of the human nasopharynx, bronchus, alveoli, and conjunctiva. We hypothesized that virus which can transmit efficiently between humans replicated well in the human upper airways. As previously reported, H1N1pdm and seasonal H1N1 viruses replicated efficiently in the nasopharyngeal, bronchial, and alveolar epithelium. In contrast, representative viruses from the classical swine (CS) (H1N1) lineage could not infect human respiratory epithelium; Eurasian avian-like swine (EA) (H1N1) viruses only infected alveolar epithelium and North American triple-reassortant (TRIG) viruses only infected the bronchial epithelium albeit inefficiently. Interestingly, a naturally occurring triple-reassortant swine virus, A/SW/HK/915/04 (H1N2), with a matrix gene segment of EA swine derivation (i.e., differing from H1N1pdm only in lacking a neuraminidase [NA] gene of EA derivation) readily infected and replicated in human nasopharyngeal and bronchial epithelia but not in the lung. A recombinant sw915 with the NA from H1N1pdm retained its tropism for the bronchus and acquired additional replication competence for alveolar epithelium. In contrast to H1N1pdm, none of the swine viruses tested nor seasonal H1N1 had tropism in human conjunctiva. Recombinant viruses generated by swapping the surface proteins (hemagglutinin and NA) of H1N1pdm and seasonal H1N1 virus demonstrated that these two gene

  3. Optimal Use of Vaccines for Control of Influenza A Virus in Swine

    PubMed Central

    Sandbulte, Matthew R.; Spickler, Anna R.; Zaabel, Pamela K.; Roth, James A.

    2015-01-01

    Influenza A virus in swine (IAV-S) is one of the most important infectious disease agents of swine in North America. In addition to the economic burden of IAV-S to the swine industry, the zoonotic potential of IAV-S sometimes leads to serious public health concerns. Adjuvanted, inactivated vaccines have been licensed in the United States for over 20 years, and there is also widespread usage of autogenous/custom IAV-S vaccines. Vaccination induces neutralizing antibodies and protection against infection with very similar strains. However, IAV-S strains are so diverse and prone to mutation that these vaccines often have disappointing efficacy in the field. This scientific review was developed to help veterinarians and others to identify the best available IAV-S vaccine for a particular infected herd. We describe key principles of IAV-S structure and replication, protective immunity, currently available vaccines, and vaccine technologies that show promise for the future. We discuss strategies to optimize the use of available IAV-S vaccines, based on information gathered from modern diagnostics and surveillance programs. Improvements in IAV-S immunization strategies, in both the short term and long term, will benefit swine health and productivity and potentially reduce risks to public health. PMID:26344946

  4. The failure of the 1976 swine influenza immunization program.

    PubMed

    Begley, S L

    1977-01-01

    The program to immunize 210 million Americans against swine flu failed. It set back the Federal government's relations with state health agencies, private physicians, pharmaceutical manufacturers, and the insurance industry. It increased mistrust of immunization programs and of government health programs in general.The well-intentioned plan had far-reaching consequences because its scope and the speed with which it was implemented were overreactions to the threat. Its size magnified every one of its faults, legal, medical and political. Organizational and scientific capacity were less than expected. Local health agencies could not administer the program with the inadequate funds from HEW and pharmaceutical companies could not produce a safe, effective children's vaccine.Because of the urgency given the program, Congress neglected the opposition of consumer advocates and state health officials, and did not spend time trying to include immunization against childhood disease in the swine flu program.The failure illustrates the dangers of hasty decisions, of considering only direct medical costs and benefits and not social and political effects on health policy, of launching a public health program whose scientific basis is weak and whose administrative requirements are untested.

  5. 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

    2014-08-01

    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.

  6. Swine influenza A (H1N1) strikes a potential for global disaster

    PubMed Central

    Galwankar, Sagar; Clem, Angela

    2009-01-01

    As of April 25th2009, 11.00 AM, eight human cases of swine influenza A virus infection have been identified in the United States in California and Texas. There is also established evidence of similar cases across the United States border in Mexico. Experts from the Centers for Disease Control and Prevention in cooperation with World Health Organization and public health experts from Canada and Mexico are leading an exhaustive investigation to find the source of infection and infected people. We present a profile of this illness from the available literature. PMID:19561969

  7. Emergence and pandemic potential of swine-origin H1N1 influenza virus.

    PubMed

    Neumann, Gabriele; Noda, Takeshi; Kawaoka, Yoshihiro

    2009-06-18

    Influenza viruses cause annual epidemics and occasional pandemics that have claimed the lives of millions. The emergence of new strains will continue to pose challenges to public health and the scientific communities. A prime example is the recent emergence of swine-origin H1N1 viruses that have transmitted to and spread among humans, resulting in outbreaks internationally. Efforts to control these outbreaks and real-time monitoring of the evolution of this virus should provide us with invaluable information to direct infectious disease control programmes and to improve understanding of the factors that determine viral pathogenicity and/or transmissibility.

  8. Local and systemic immune response in pigs during subclinical and clinical swine influenza infection.

    PubMed

    Pomorska-Mól, M; Kwit, K; Markowska-Daniel, I; Kowalski, C; Pejsak, Z

    2014-10-01

    Local and systemic immune responses in pigs intranasally (IN) and intratracheally (IT) inoculated with swine influenza virus (SIV) were studied. No clinical signs were observed in IN-inoculated pigs, while IT-inoculated pigs developed typical signs of influenza. Significantly higher titres of specific antibodies and changes of haematological parameters were found only in IT-inoculated pigs. Because positive correlations between viral titre, local cytokine concentration, and lung pathology have been observed, we hypothesise that both viral load and the local secretion of cytokines play a role in the induction of lung lesions. It could be that a higher replication of SIV stimulates immune cells to secrete higher amounts of cytokines. The results of the present study indicate that pathogenesis of SIV is dependent on both, the damage caused to the lung parenchyma directly by virus, and the effects on the cells of the host's immune system.

  9. Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic.

    PubMed

    Smith, Gavin J D; Vijaykrishna, Dhanasekaran; Bahl, Justin; Lycett, Samantha J; Worobey, Michael; Pybus, Oliver G; Ma, Siu Kit; Cheung, Chung Lam; Raghwani, Jayna; Bhatt, Samir; Peiris, J S Malik; Guan, Yi; Rambaut, Andrew

    2009-06-25

    In March and early April 2009, a new swine-origin influenza A (H1N1) virus (S-OIV) emerged in Mexico and the United States. During the first few weeks of surveillance, the virus spread worldwide to 30 countries (as of May 11) by human-to-human transmission, causing the World Health Organization to raise its pandemic alert to level 5 of 6. This virus has the potential to develop into the first influenza pandemic of the twenty-first century. Here we use evolutionary analysis to estimate the timescale of the origins and the early development of the S-OIV epidemic. We show that it was derived from several viruses circulating in swine, and that the initial transmission to humans occurred several months before recognition of the outbreak. A phylogenetic estimate of the gaps in genetic surveillance indicates a long period of unsampled ancestry before the S-OIV outbreak, suggesting that the reassortment of swine lineages may have occurred years before emergence in humans, and that the multiple genetic ancestry of S-OIV is not indicative of an artificial origin. Furthermore, the unsampled history of the epidemic means that the nature and location of the genetically closest swine viruses reveal little about the immediate origin of the epidemic, despite the fact that we included a panel of closely related and previously unpublished swine influenza isolates. Our results highlight the need for systematic surveillance of influenza in swine, and provide evidence that the mixing of new genetic elements in swine can result in the emergence of viruses with pandemic potential in humans.

  10. DNA Vaccination Elicits Protective Immune Responses against Pandemic and Classic Swine Influenza Viruses in Pigs ▿ †

    PubMed Central

    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.

    2011-01-01

    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. PMID:21918118

  11. Simultaneous detection of influenza viruses A, B, and swine origin influenza A using multiplex one-step real-time RT-PCR assay.

    PubMed

    Monavari, S H R; Mollaie, H R; Fazlalipour, M

    2014-01-01

    Every year, seasonal epidemics of influenza viruses are causing considerable morbidity and mortality worldwide. Also infrequent novel and rearranged strains of influenza viruses have caused quick, acute universal pandemics resulting in millions of mortalities. The usage of efficient and accurate detection is superior for infection control, effective treatment, and epidemiological supervision. Therefore, evaluation of useful real-time PCR molecular tests for the detection of pandemic viruses is important before the next wave of the pandemic. A novel quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) assay with specific primers was used successfully for detection and monitoring of the influenza A, B, and swine influenza. The newly designed primers target highly conserved regions in influenza viruses. Our qRT-PCR assay is highly specific for detecting influenza A, B, and swine influenza viruses. The cutoff CT value was determined <38 for domestic human diagnostic test, under conditions of FDA emergency, and the reaction efficiency of the InfA, swInfA, and InfB assays were thereby estimated to be 97.9 % (R2 = 0.998), 98.3 % (R2 = 0.986), and 99.5 % (R2 = 0.995), respectively. Interestingly, based on our finding, there is no cross reactivity of detecting other viruses.

  12. Isolation of swine influenza virus in cell cultures and embryonated chicken eggs.

    PubMed

    Zhang, Jianqiang; Gauger, Phillip C

    2014-01-01

    Influenza virus isolation is a procedure to obtain a live and infectious virus that can be used for antigenic characterization, pathogenesis investigation, and vaccine production. Embryonated chicken egg inoculation is traditionally considered the "gold standard" method for influenza virus isolation and propagation. However, many primary cells and continuous cell lines have also been examined or developed for influenza virus isolation and replication. Specifically, swine influenza virus (SIV) isolation and propagation have been attempted and compared in embryonated chicken eggs, some primary porcine cells, and a number of continuous cell lines. Currently Madin-Darby canine kidney (MDCK) cells remain the most commonly used cell line for isolation, propagation, and titration of SIV. Virus isolation in embryonated chicken eggs or in different cell lines offers alternative approaches when SIV isolation in MDCK cells is unsuccessful. Nasal swabs, lung tissues, and oral fluids are three major specimen types for SIV isolation. In this chapter, we describe the procedures of sample processing, SIV isolation in MDCK cells and in embryonated chicken eggs, as well as methods used for confirming the virus isolation results.

  13. Modeling influenza epidemics and pandemics: insights into the future of swine flu (H1N1)

    PubMed Central

    Coburn, Brian J; Wagner, Bradley G; Blower, Sally

    2009-01-01

    Here we present a review of the literature of influenza modeling studies, and discuss how these models can provide insights into the future of the currently circulating novel strain of influenza A (H1N1), formerly known as swine flu. We discuss how the feasibility of controlling an epidemic critically depends on the value of the Basic Reproduction Number (R0). The R0 for novel influenza A (H1N1) has recently been estimated to be between 1.4 and 1.6. This value is below values of R0 estimated for the 1918–1919 pandemic strain (mean R0~2: range 1.4 to 2.8) and is comparable to R0 values estimated for seasonal strains of influenza (mean R0 1.3: range 0.9 to 2.1). By reviewing results from previous modeling studies we conclude it is theoretically possible that a pandemic of H1N1 could be contained. However it may not be feasible, even in resource-rich countries, to achieve the necessary levels of vaccination and treatment for control. As a recent modeling study has shown, a global cooperative strategy will be essential in order to control a pandemic. This strategy will require resource-rich countries to share their vaccines and antivirals with resource-constrained and resource-poor countries. We conclude our review by discussing the necessity of developing new biologically complex models. We suggest that these models should simultaneously track the transmission dynamics of multiple strains of influenza in bird, pig and human populations. Such models could be critical for identifying effective new interventions, and informing pandemic preparedness planning. Finally, we show that by modeling cross-species transmission it may be possible to predict the emergence of pandemic strains of influenza. PMID:19545404

  14. Modeling influenza epidemics and pandemics: insights into the future of swine flu (H1N1).

    PubMed

    Coburn, Brian J; Wagner, Bradley G; Blower, Sally

    2009-06-22

    Here we present a review of the literature of influenza modeling studies, and discuss how these models can provide insights into the future of the currently circulating novel strain of influenza A (H1N1), formerly known as swine flu. We discuss how the feasibility of controlling an epidemic critically depends on the value of the Basic Reproduction Number (R0). The R0 for novel influenza A (H1N1) has recently been estimated to be between 1.4 and 1.6. This value is below values of R0 estimated for the 1918-1919 pandemic strain (mean R0 approximately 2: range 1.4 to 2.8) and is comparable to R0 values estimated for seasonal strains of influenza (mean R0 1.3: range 0.9 to 2.1). By reviewing results from previous modeling studies we conclude it is theoretically possible that a pandemic of H1N1 could be contained. However it may not be feasible, even in resource-rich countries, to achieve the necessary levels of vaccination and treatment for control. As a recent modeling study has shown, a global cooperative strategy will be essential in order to control a pandemic. This strategy will require resource-rich countries to share their vaccines and antivirals with resource-constrained and resource-poor countries. We conclude our review by discussing the necessity of developing new biologically complex models. We suggest that these models should simultaneously track the transmission dynamics of multiple strains of influenza in bird, pig and human populations. Such models could be critical for identifying effective new interventions, and informing pandemic preparedness planning. Finally, we show that by modeling cross-species transmission it may be possible to predict the emergence of pandemic strains of influenza.

  15. Co-circulation of H5N6, H3N2, H3N8, and Emergence of Novel Reassortant H3N6 in a Local Community in Hunan Province in China

    PubMed Central

    Li, Xuyong; Yang, Jiayun; Liu, Bin; Jia, Yane; Guo, Jing; Gao, Xue; Weng, Shaoting; Yang, Maijuan; Wang, Liang; Wang, Lin-Fa; Cui, Jie; Chen, Hualan; Zhu, Qiyun

    2016-01-01

    Multiple infections of avian influenza viruses (AIVs) in poultry or wild birds contribute to the continued evolution of H5 subtype viruses in nature and provide potential recombination of AIVs of different origins. In this study, we carried out surveillance of AIVs in ducks, geese and the environment of a community in Hunan province, China, from 2014–2015. We isolated multiple co-circulated AIVs including H3N2, H3N8, and H5N6, and, most importantly, a novel reassortant: H3N6. Phylogenetic analyses suggest that H3N6 is highly likely derived from H5N6, which has recently been shown to have zoonotic potential with human infections. Studies with mammalian cell lines and a mouse model indicate that four selected AIVs of duck or goose origin can infect MDCK and A549 cells but have low pathogenicity in mice. We propose that a potential co-circulation of multiple subtypes including H5N6 in local area may result in the production of novel subtypes such as H3N6 by gene reassortment. PMID:27151540

  16. Co-circulation of H5N6, H3N2, H3N8, and Emergence of Novel Reassortant H3N6 in a Local Community in Hunan Province in China.

    PubMed

    Li, Xuyong; Yang, Jiayun; Liu, Bin; Jia, Yane; Guo, Jing; Gao, Xue; Weng, Shaoting; Yang, Maijuan; Wang, Liang; Wang, Lin-Fa; Cui, Jie; Chen, Hualan; Zhu, Qiyun

    2016-01-01

    Multiple infections of avian influenza viruses (AIVs) in poultry or wild birds contribute to the continued evolution of H5 subtype viruses in nature and provide potential recombination of AIVs of different origins. In this study, we carried out surveillance of AIVs in ducks, geese and the environment of a community in Hunan province, China, from 2014-2015. We isolated multiple co-circulated AIVs including H3N2, H3N8, and H5N6, and, most importantly, a novel reassortant: H3N6. Phylogenetic analyses suggest that H3N6 is highly likely derived from H5N6, which has recently been shown to have zoonotic potential with human infections. Studies with mammalian cell lines and a mouse model indicate that four selected AIVs of duck or goose origin can infect MDCK and A549 cells but have low pathogenicity in mice. We propose that a potential co-circulation of multiple subtypes including H5N6 in local area may result in the production of novel subtypes such as H3N6 by gene reassortment. PMID:27151540

  17. Development of a Rapid Automated Influenza A, Influenza B, and Respiratory Syncytial Virus A/B Multiplex Real-Time RT-PCR Assay and Its Use during the 2009 H1N1 Swine-Origin Influenza Virus Epidemic in Milwaukee, Wisconsin

    PubMed Central

    Beck, Eric T.; Jurgens, Lisa A.; Kehl, Sue C.; Bose, Michael E.; Patitucci, Teresa; LaGue, Elizabeth; Darga, Patrick; Wilkinson, Kimberly; Witt, Lorraine M.; Fan, Jiang; He, Jie; Kumar, Swati; Henrickson, Kelly J.

    2010-01-01

    Rapid, semiautomated, and fully automated multiplex real-time RT-PCR assays were developed and validated for the detection of influenza (Flu) A, Flu B, and respiratory syncytial virus (RSV) from nasopharyngeal specimens. The assays can detect human H1N1, H3N2, and swine-origin (S-OIV) H1N1 Flu A viruses and were effectively used to distinguish Flu A infections (of all subtypes) from Flu B and RSV infections during the current S-OIV outbreak in Milwaukee, WI. The analytical limits of detection were 10−2 to 101 TCID50/ml depending on the platform and analyte and showed only one minor cross-reaction among 23 common respiratory pathogens (intermittent cross-reaction to adenovirus at >107 TCID50/ml). A total of 100 clinical samples were tested by tissue culture, both automated assays, and the US Food and Drug Administration-approved ProFlu+ assay. Both the semiautomated and fully automated assays exhibited greater overall (Flu A, Flu B, and RSV combined) clinical sensitivities (93 and 96%, respectively) and individual Flu A sensitivities (100%) than the Food and Drug Administration-approved test (89% overall sensitivity and 93% Flu A sensitivity). All assays were 99% specific. During the S-OIV outbreak in Milwaukee, WI, the fully automated assay was used to test 1232 samples in 2 weeks. Flu A was detected in 134 clinical samples (126 H1N1 S-OIV, 5 H1N1 [human], and 1 untyped) with 100% positive agreement compared with other “in-house” validated molecular assays, with only 2 false-positive results. Such accurate testing using automated high-throughput molecule systems should allow clinicians and public health officials to react quickly and effectively during viral outbreaks. PMID:19959800

  18. Development of a rapid automated influenza A, influenza B, and respiratory syncytial virus A/B multiplex real-time RT-PCR assay and its use during the 2009 H1N1 swine-origin influenza virus epidemic in Milwaukee, Wisconsin.

    PubMed

    Beck, Eric T; Jurgens, Lisa A; Kehl, Sue C; Bose, Michael E; Patitucci, Teresa; LaGue, Elizabeth; Darga, Patrick; Wilkinson, Kimberly; Witt, Lorraine M; Fan, Jiang; He, Jie; Kumar, Swati; Henrickson, Kelly J

    2010-01-01

    Rapid, semiautomated, and fully automated multiplex real-time RT-PCR assays were developed and validated for the detection of influenza (Flu) A, Flu B, and respiratory syncytial virus (RSV) from nasopharyngeal specimens. The assays can detect human H1N1, H3N2, and swine-origin (S-OIV) H1N1 Flu A viruses and were effectively used to distinguish Flu A infections (of all subtypes) from Flu B and RSV infections during the current S-OIV outbreak in Milwaukee, WI. The analytical limits of detection were 10(-2) to 10(1) TCID(50)/ml depending on the platform and analyte and showed only one minor cross-reaction among 23 common respiratory pathogens (intermittent cross-reaction to adenovirus at >10(7) TCID(50)/ml). A total of 100 clinical samples were tested by tissue culture, both automated assays, and the US Food and Drug Administration-approved ProFlu+ assay. Both the semiautomated and fully automated assays exhibited greater overall (Flu A, Flu B, and RSV combined) clinical sensitivities (93 and 96%, respectively) and individual Flu A sensitivities (100%) than the Food and Drug Administration-approved test (89% overall sensitivity and 93% Flu A sensitivity). All assays were 99% specific. During the S-OIV outbreak in Milwaukee, WI, the fully automated assay was used to test 1232 samples in 2 weeks. Flu A was detected in 134 clinical samples (126 H1N1 S-OIV, 5 H1N1 [human], and 1 untyped) with 100% positive agreement compared with other "in-house" validated molecular assays, with only 2 false-positive results. Such accurate testing using automated high-throughput molecule systems should allow clinicians and public health officials to react quickly and effectively during viral outbreaks.

  19. The molecular determinants of antibody recognition and antigenic drift in the H3 hemagglutinin of swine influenza A virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Serum virus neutralization assay for detection and quantitation of serum neutralizing antibodies to influenza A virus in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The serum virus neutralization (SVN) assay is a serological test to detect the presence and magnitude of functional systemic antibodies that prevent infectivity of a virus. The SVN assay is a highly sensitive and specific test that may be applied to influenza A viruses (IAV) in swine to measure the ...

  1. Cross Protection against Influenza A Virus by Yeast-Expressed Heterologous Tandem Repeat M2 Extracellular Proteins.

    PubMed

    Lee, Yu-Na; Kim, Min-Chul; Lee, Young-Tae; Hwang, Hye Suk; Lee, Jongsang; Kim, Cheol; Kang, Sang-Moo

    2015-01-01

    The influenza M2 ectodomain (M2e) is well conserved across human influenza A subtypes, but there are few residue changes among avian and swine origin influenza A viruses. We expressed a tandem repeat construct of heterologous M2e sequences (M2e5x) derived from human, swine, and avian origin influenza A viruses using the yeast expression system. Intramuscular immunization of mice with AS04-adjuvanted M2e5x protein vaccines was effective in inducing M2e-specific antibodies reactive to M2e peptide and native M2 proteins on the infected cells with human, swine, or avian influenza virus, mucosal and systemic memory cellular immune responses, and cross-protection against H3N2 virus. Importantly, M2e5x immune sera were found to confer protection against different subtypes of H1N1 and H5N1 influenza A viruses in naïve mice. Also, M2e5x-immune complexes of virus-infected cells stimulated macrophages to secrete cytokines via Fc receptors, indicating a possible mechanism of protection. The present study provides evidence that M2e5x proteins produced in yeast cells could be developed as a potential universal influenza vaccine. PMID:26366729

  2. α-Galactosylceramide protects swine against influenza infection when administered as a vaccine adjuvant

    PubMed Central

    Artiaga, Bianca L.; Yang, Guan; Hackmann, Timothy J.; Liu, Qinfang; Richt, Jürgen A.; Salek-Ardakani, Shahram; Castleman, William L.; Lednicky, John A.; Driver, John P.

    2016-01-01

    Natural killer T (NKT) -cells activated with the glycolipid ligand α-galactosylceramide (α-GalCer) stimulate a wide array of immune responses with many promising immunotherapeutic applications, including the enhancement of vaccines against infectious diseases and cancer. In the current study, we evaluated whether α-GalCer generates protective immunity against a swine influenza (SI) virus infection when applied as an intramuscular vaccine adjuvant. Immunization of newly weaned piglets with UV-killed pandemic H1N1 A/California/04/2009 (kCA04) SI virus and α-GalCer induced high titers of anti-hemagglutinin antibodies and generated virus-specific T cells that localized in intrapulmonary airways and in alveolar walls. Vaccination with α-GalCer resulted in a systemic increase in NKT-cell concentrations, including in the respiratory tract, which was associated with complete inhibition of viral replication in the upper and lower respiratory tract and much reduced viral shedding. These results indicate that NKT-cell agonists could be used to improve swine vaccine formulations in order to reduce the clinical signs of SI infection and limit the spread of influenza viruses amongst commercial pigs. PMID:27004737

  3. 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.

  4. Isolation and phylogenetic analysis of avian-origin European H1N1 swine influenza viruses in Jiangsu, China.

    PubMed

    Zhao, Guo; Pan, Jinjin; Gu, Xiaobing; Lu, Xinlun; Li, Qunhui; Zhu, Jie; Chen, Chaoyang; Duan, Zhiqiang; Xu, Quangang; Wang, Xiaobo; Hu, Shunlin; Liu, Wenbo; Peng, Daxin; Liu, Xiaowen; Wang, Xiaoquan; Liu, Xiufan

    2012-04-01

    Isolates of the A(H1N1)pdm2009 virus were first identified in asymptomatic swine in Jiangsu province, China in January 2010, indicating that the virus has retro-infected swine after circulating through humans in mainland China. The purpose of this study was to determine whether the avian-origin European H1N1 swine influenza virus (SIV) and the A(H1N1)pdm2009 virus are cocirculating in swine in Jiangsu province of China. From May 2010 to May 2011, 1,030 nasal swab samples were collected from healthy swine in Jiangsu province of China and were tested for influenza A H1N1 using reverse transcription-PCR. Fragments of the complete genomes of viruses from the samples that were positive for influenza A H1N1 were sequenced and analysed. A total of 32 avian-origin European H1N1 SIVs were isolated, and no A(H1N1)pdm2009 viruses were identified; full-length genomes of 18 strains were sequenced. The eight gene segments of some of the isolated H1N1 viruses have 99.1-99.8% sequence identity with the human A/Jiangsu/ALS1/2011(H1N1) isolates in the same region. Our study indicates that the avian-origin European H1N1 SIVs remain endemic in swine and have retro-infected humans after circulating through swine, which may present a risk factor for public health.

  5. Pathogenicity and Transmissibility of North American Triple Reassortant Swine Influenza A Viruses in Ferrets

    PubMed Central

    Barman, Subrata; Krylov, Petr S.; Fabrizio, Thomas P.; Franks, John; Turner, Jasmine C.; Seiler, Patrick; Wang, David; Rehg, Jerold E.; Erickson, Gene A.; Gramer, Marie; Webster, Robert G.; Webby, Richard J.

    2012-01-01

    North American triple reassortant swine (TRS) influenza A viruses have caused sporadic human infections since 2005, but human-to-human transmission has not been documented. These viruses have six gene segments (PB2, PB1, PA, HA, NP, and NS) closely related to those of the 2009 H1N1 pandemic viruses. Therefore, understanding of these viruses' pathogenicity and transmissibility may help to identify determinants of virulence of the 2009 H1N1 pandemic viruses and to elucidate potential human health threats posed by the TRS viruses. Here we evaluated in a ferret model the pathogenicity and transmissibility of three groups of North American TRS viruses containing swine-like and/or human-like HA and NA gene segments. The study was designed only to detect informative and significant patterns in the transmissibility and pathogenicity of these three groups of viruses. We observed that irrespective of their HA and NA lineages, the TRS viruses were moderately pathogenic in ferrets and grew efficiently in both the upper and lower respiratory tracts. All North American TRS viruses studied were transmitted between ferrets via direct contact. However, their transmissibility by respiratory droplets was related to their HA and NA lineages: TRS viruses with human-like HA and NA were transmitted most efficiently, those with swine-like HA and NA were transmitted minimally or not transmitted, and those with swine-like HA and human-like NA (N2) showed intermediate transmissibility. We conclude that the lineages of HA and NA may play a crucial role in the respiratory droplet transmissibility of these viruses. These findings have important implications for pandemic planning and warrant confirmation. PMID:22829764

  6. Influenza A virus acquires enhanced pathogenicity and transmissibility after serial passages in swine.

    PubMed

    Wei, Kai; Sun, Honglei; Sun, Zhenhong; Sun, Yipeng; Kong, Weili; Pu, Juan; Ma, Guangpeng; Yin, Yanbo; Yang, Hanchun; Guo, Xin; Chang, Kin-Chow; Liu, Jinhua

    2014-10-01

    Genetic and phylogenetic analyses suggest that the pandemic H1N1/2009 virus was derived from well-established swine influenza lineages; however, there is no convincing evidence that the pandemic virus was generated from a direct precursor in pigs. Furthermore, the evolutionary dynamics of influenza virus in pigs have not been well documented. Here, we subjected a recombinant virus (rH1N1) with the same constellation makeup as the pandemic H1N1/2009 virus to nine serial passages in pigs. The severity of infection sequentially increased with each passage. Deep sequencing of viral quasispecies from the ninth passage found five consensus amino acid mutations: PB1 A469T, PA 1129T, NA N329D, NS1 N205K, and NEP T48N. Mutations in the hemagglutinin (HA) protein, however, differed greatly between the upper and lower respiratory tracts. Three representative viral clones with the five consensus mutations were selected for functional evaluation. Relative to the parental virus, the three viral clones showed enhanced replication and polymerase activity in vitro and enhanced replication, pathogenicity, and transmissibility in pigs, guinea pigs, and ferrets in vivo. Specifically, two mutants of rH1N1 (PB1 A469T and a combination of NS1 N205K and NEP T48N) were identified as determinants of transmissibility in guinea pigs. Crucially, one mutant viral clone with the five consensus mutations, which also carried D187E, K211E, and S289N mutations in its HA, additionally was able to infect ferrets by airborne transmission as effectively as the pandemic virus. Our findings demonstrate that influenza virus can acquire viral characteristics that are similar to those of the pandemic virus after limited serial passages in pigs. Importance: We demonstrate here that an engineered reassortant swine influenza virus, with the same gene constellation pattern as the pandemic H1N1/2009 virus and subjected to only nine serial passages in pigs, acquired greatly enhanced virulence and transmissibility

  7. Efficient isolation of Swine influenza viruses by age-targeted specimen collection.

    PubMed

    Ozawa, Makoto; Matsuu, Aya; Yonezawa, Kouki; Igarashi, Manabu; Okuya, Kosuke; Kawabata, Toshiko; Ito, Kimihito; Tsukiyama-Kohara, Kyoko; Taneno, Akira; Deguchi, Eisaburo

    2015-04-01

    The control of swine influenza virus (SIV) infection is paramount for increasing the productivity of pig farming and minimizing the threat of pandemic outbreaks. Thus, SIV surveillance should be conducted by region and on a regular basis. Here, we established a microneutralization assay specific for SIV seroprevalence surveillance by using reporter gene-expressing recombinant influenza viruses. Growth-based SIV seroprevalence revealed that most sows and piglets were positive for neutralizing antibodies against influenza viruses. In contrast, the 90-day-old growing pigs exhibited limited neutralizing activity in their sera, suggesting that this particular age of population is most susceptible to SIV infection and thus is an ideal age group for SIV isolation. From nasal swab specimens of healthy pigs in this age population, we were able to isolate SIVs at a higher incidence (5.3%) than those of previous reports. Nucleotide sequencing and phylogenetic analysis of the hemagglutinin (HA) genes revealed that the isolated SIVs have circulated and evolved in pigs but not have been recently introduced from humans, implying that a large number of SIV lineages may remain "undiscovered" in the global porcine populations. We propose that the 90-day-old growing pig-targeted nasal swab collection presented in this study facilitates global SIV surveillance and contributes to the detection and control of SIV infection.

  8. Genetic and pathobiologic characterization of pandemic H1N1 2009 influenza viruses from a naturally infected swine herd.

    PubMed

    Weingartl, Hana M; Berhane, Yohannes; Hisanaga, Tamiko; Neufeld, James; Kehler, Helen; Emburry-Hyatt, Carissa; Hooper-McGreevy, Kathleen; Kasloff, Samantha; Dalman, Brett; Bystrom, Jan; Alexandersen, Soren; Li, Yan; Pasick, John

    2010-03-01

    Since its initial identification in Mexico and the United States, concerns have been raised that the novel H1N1 influenza virus might cause a pandemic of severity comparable to that of the 1918 pandemic. In late April 2009, viruses phylogenetically related to pandemic H1N1 influenza virus were isolated from an outbreak on a Canadian pig farm. This outbreak also had epidemiological links to a suspected human case. Experimental infections carried out in pigs using one of the swine isolates from this outbreak and the human isolate A/Mexico/InDRE4487/2009 showed differences in virus recovery from the lower respiratory tract. Virus was consistently isolated from the lungs of pigs infected with A/Mexico/InDRE4487/2009, while only one pig infected with A/swine/Alberta/OTH-33-8/2008 yielded live virus from the lung, despite comparable amounts of viral RNA and antigen in both groups of pigs. Clinical disease resembled other influenza virus infections in swine, albeit with somewhat prolonged virus antigen detection and delayed viral-RNA clearance from the lungs. There was also a noteworthy amount of genotypic variability among the viruses isolated from the pigs on the farm. This, along with the somewhat irregular pathobiological characteristics observed in experimentally infected animals, suggests that although the virus may be of swine origin, significant viral evolution may still be ongoing.

  9. Experimental Inoculation of Pigs with Pandemic H1N1 2009 Virus and HI Cross-Reactivity with Contemporary Swine Influenza Virus Antisera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In March-April 2009, a novel A/H1N1 emerged in the human population in North America. The gene constellation of the virus was demonstrated to be a combination from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before been identified in swine or other species...

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

    PubMed Central

    2009-01-01

    Background 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. Methods 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 Results 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. Conclusion Initial responses to Influenza A

  11. Prevalence, genetics, and transmissibility in ferrets of Eurasian avian-like H1N1 swine influenza viruses

    PubMed Central

    Yang, Huanliang; Chen, Yan; Qiao, Chuanling; He, Xijun; Zhou, Hong; Sun, Yu; Yin, Hang; Meng, Shasha; Liu, Liping; Zhang, Qianyi; Kong, Huihui; Gu, Chunyang; Li, Chengjun; Bu, Zhigao; Kawaoka, Yoshihiro; Chen, Hualan

    2016-01-01

    Pigs are important intermediate hosts for generating novel influenza viruses. The Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses (SIVs) have circulated in pigs since 1979, and human cases associated with EAH1N1 SIVs have been reported in several countries. However, the biologic properties of EAH1N1 SIVs are largely unknown. Here, we performed extensive influenza surveillance in pigs in China and isolated 228 influenza viruses from 36,417 pigs. We found that 139 of the 228 strains from pigs in 10 provinces in China belong to the EAH1N1 lineage. These viruses formed five genotypes, with two distinct antigenic groups, represented by A/swine/Guangxi/18/2011 and A/swine/Guangdong/104/2013, both of which are antigenically and genetically distinct from the current human H1N1 viruses. Importantly, the EAH1N1 SIVs preferentially bound to human-type receptors, and 9 of the 10 tested viruses transmitted in ferrets by respiratory droplet. We found that 3.6% of children (≤10 y old), 0% of adults, and 13.4% of elderly adults (≥60 y old) had neutralization antibodies (titers ≥40 in children and ≥80 in adults) against the EAH1N1 A/swine/Guangxi/18/2011 virus, but none of them had such neutralization antibodies against the EAH1N1 A/swine/Guangdong/104/2013 virus. Our study shows the potential of EAH1N1 SIVs to transmit efficiently in humans and suggests that immediate action is needed to prevent the efficient transmission of EAH1N1 SIVs to humans. PMID:26711995

  12. Prevalence, genetics, and transmissibility in ferrets of Eurasian avian-like H1N1 swine influenza viruses.

    PubMed

    Yang, Huanliang; Chen, Yan; Qiao, Chuanling; He, Xijun; Zhou, Hong; Sun, Yu; Yin, Hang; Meng, Shasha; Liu, Liping; Zhang, Qianyi; Kong, Huihui; Gu, Chunyang; Li, Chengjun; Bu, Zhigao; Kawaoka, Yoshihiro; Chen, Hualan

    2016-01-12

    Pigs are important intermediate hosts for generating novel influenza viruses. The Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses (SIVs) have circulated in pigs since 1979, and human cases associated with EAH1N1 SIVs have been reported in several countries. However, the biologic properties of EAH1N1 SIVs are largely unknown. Here, we performed extensive influenza surveillance in pigs in China and isolated 228 influenza viruses from 36,417 pigs. We found that 139 of the 228 strains from pigs in 10 provinces in China belong to the EAH1N1 lineage. These viruses formed five genotypes, with two distinct antigenic groups, represented by A/swine/Guangxi/18/2011 and A/swine/Guangdong/104/2013, both of which are antigenically and genetically distinct from the current human H1N1 viruses. Importantly, the EAH1N1 SIVs preferentially bound to human-type receptors, and 9 of the 10 tested viruses transmitted in ferrets by respiratory droplet. We found that 3.6% of children (≤10 y old), 0% of adults, and 13.4% of elderly adults (≥60 y old) had neutralization antibodies (titers ≥40 in children and ≥80 in adults) against the EAH1N1 A/swine/Guangxi/18/2011 virus, but none of them had such neutralization antibodies against the EAH1N1 A/swine/Guangdong/104/2013 virus. Our study shows the potential of EAH1N1 SIVs to transmit efficiently in humans and suggests that immediate action is needed to prevent the efficient transmission of EAH1N1 SIVs to humans.

  13. Prevalence, genetics, and transmissibility in ferrets of Eurasian avian-like H1N1 swine influenza viruses.

    PubMed

    Yang, Huanliang; Chen, Yan; Qiao, Chuanling; He, Xijun; Zhou, Hong; Sun, Yu; Yin, Hang; Meng, Shasha; Liu, Liping; Zhang, Qianyi; Kong, Huihui; Gu, Chunyang; Li, Chengjun; Bu, Zhigao; Kawaoka, Yoshihiro; Chen, Hualan

    2016-01-12

    Pigs are important intermediate hosts for generating novel influenza viruses. The Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses (SIVs) have circulated in pigs since 1979, and human cases associated with EAH1N1 SIVs have been reported in several countries. However, the biologic properties of EAH1N1 SIVs are largely unknown. Here, we performed extensive influenza surveillance in pigs in China and isolated 228 influenza viruses from 36,417 pigs. We found that 139 of the 228 strains from pigs in 10 provinces in China belong to the EAH1N1 lineage. These viruses formed five genotypes, with two distinct antigenic groups, represented by A/swine/Guangxi/18/2011 and A/swine/Guangdong/104/2013, both of which are antigenically and genetically distinct from the current human H1N1 viruses. Importantly, the EAH1N1 SIVs preferentially bound to human-type receptors, and 9 of the 10 tested viruses transmitted in ferrets by respiratory droplet. We found that 3.6% of children (≤10 y old), 0% of adults, and 13.4% of elderly adults (≥60 y old) had neutralization antibodies (titers ≥40 in children and ≥80 in adults) against the EAH1N1 A/swine/Guangxi/18/2011 virus, but none of them had such neutralization antibodies against the EAH1N1 A/swine/Guangdong/104/2013 virus. Our study shows the potential of EAH1N1 SIVs to transmit efficiently in humans and suggests that immediate action is needed to prevent the efficient transmission of EAH1N1 SIVs to humans. PMID:26711995

  14. Swine influenza H1N1 virus induces acute inflammatory immune responses in pig lungs: a potential animal model for human H1N1 influenza virus.

    PubMed

    Khatri, Mahesh; Dwivedi, Varun; Krakowka, Steven; Manickam, Cordelia; Ali, Ahmed; Wang, Leyi; Qin, Zhuoming; Renukaradhya, Gourapura J; Lee, Chang-Won

    2010-11-01

    Pigs are capable of generating reassortant influenza viruses of pandemic potential, as both the avian and mammalian influenza viruses can infect pig epithelial cells in the respiratory tract. The source of the current influenza pandemic is H1N1 influenza A virus, possibly of swine origin. This study was conducted to understand better the pathogenesis of H1N1 influenza virus and associated host mucosal immune responses during acute infection in humans. Therefore, we chose a H1N1 swine influenza virus, Sw/OH/24366/07 (SwIV), which has a history of transmission to humans. Clinically, inoculated pigs had nasal discharge and fever and shed virus through nasal secretions. Like pandemic H1N1, SwIV also replicated extensively in both the upper and lower respiratory tracts, and lung lesions were typical of H1N1 infection. We detected innate, proinflammatory, Th1, Th2, and Th3 cytokines, as well as SwIV-specific IgA antibody in lungs of the virus-inoculated pigs. Production of IFN-γ by lymphocytes of the tracheobronchial lymph nodes was also detected. Higher frequencies of cytotoxic T lymphocytes, γδ T cells, dendritic cells, activated T cells, and CD4+ and CD8+ T cells were detected in SwIV-infected pig lungs. Concomitantly, higher frequencies of the immunosuppressive T regulatory cells were also detected in the virus-infected pig lungs. The findings of this study have relevance to pathogenesis of the pandemic H1N1 influenza virus in humans; thus, pigs may serve as a useful animal model to design and test effective mucosal vaccines and therapeutics against influenza virus.

  15. Distribution of antibodies against influenza virus in pigs from farrow-to-finish farms in Minas Gerais state, Brazil

    PubMed Central

    Dias, Alessandra S; Costa, Érica A; Rajão, Daniela S; Guedes, Roberto M C; Ciacci Zanella, Janice R; Lobato, Zélia I P

    2015-01-01

    Background Swine influenza virus (SIV) is the cause of an acute respiratory disease that affects swine worldwide. In Brazil, SIV has been identified in pigs since 1978. After the emergence of pandemic H1N1 in 2009 (H1N1pdm09), few studies reported the presence of influenza virus in Brazilian herds. Objectives The objective of this study was to evaluate the serological profile for influenza virus in farrow-to-finish pig farms in Minas Gerais state, Brazil. Methods Thirty farms with no SIV vaccination history were selected from the four larger pig production areas in Minas Gerais state (Zona da Mata, Triângulo Mineiro/Alto Paranaíba, South/Southwest and the Belo Horizonte metropolitan area). At each farm, blood samples were randomly collected from 20 animals in each production cycle category: breeding animals (sows and gilts), farrowing crate (2–3 weeks), nursery (4–7 weeks), grower pigs (8–14 weeks), and finishing pigs (15–16 weeks), with 100 samples per farm and a total of 3000 animals in this study. The samples were tested for hemagglutination inhibition activity against H1N1 pandemic strain (A/swine/Brazil/11/2009) and H3N2 SIV (A/swine/Iowa/8548-2/98) reference strain. Results The percentages of seropositive animals for H1N1pdm09 and H3N2 were 26·23% and 1·57%, respectively, and the percentages of seropositive herds for both viruses were 96·6% and 13·2%, respectively. Conclusions The serological profiles differed for both viruses and among the studied areas, suggesting a high variety of virus circulation around the state, as well as the presence of seronegative animals susceptible to influenza infection and, consequently, new respiratory disease outbreaks. PMID:25648743

  16. Assessment for possible healthcare-associated transmission of a new variant influenza virus--Pennsylvania, August 2011.

    PubMed

    Greenbaum, Adena H; Wong, K; Nguyen, D; Smith, E; Torso, L; Chen, G; Wise, M; Casey, M; Ostroff, S; Nambiar, A; Nalluswami, K; Miller, J; Lute, J; Klimov, A; Emery, S; Green, M; Giampa, P; Moll, M; Finelli, L; Jhung, M

    2013-12-01

    In August 2011, one of the earliest cases of influenza A(H3N2) variant [A(H3N2)v] virus infection was hospitalized with severe illness. To investigate the potential for healthcare-associated transmission of influenza A(H3N2)v, we evaluated both healthcare providers and patient contacts of the case. We found that healthcare-associated transmission was unlikely.

  17. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 percent within one to two days of initial symptoms being recognized and approximately two dozen people developed influenza-like illness. Triple reassort...

  19. Utility of snout wipe samples for influenza A virus surveillance in exhibition swine populations

    PubMed Central

    Edwards, Jody L; Nelson, Sarah W; Workman, Jeffrey D; Slemons, Richard D; Szablewski, Christine M; Nolting, Jacqueline M; Bowman, Andrew S

    2014-01-01

    Background Sporadic influenza A virus (IAV) outbreaks in humans and swine have resulted from commingling of large numbers of people and pigs at agricultural fairs in the United States. Current antemortem IAV surveillance strategies in swine require collecting nasal swabs, which entails restraining pigs with snares. Restraint is labor-intensive for samplers, stressful for pigs, and displeasing to onlookers because pigs often resist and vocalize. Objective To evaluate the utility of snout wipes in exhibition swine as a method to make IAV surveillance efforts less intrusive, less labor-intensive, and more widely accepted among pig owners and exhibition officials. Methods Three materials (rayon/polyester gauze, cotton gauze, and Swiffer® Sweeper dry cloths) were inoculated with IAV, and viral recoveries from these materials were quantified using qRT-PCR and TCID50 assays. In a field trial, paired cotton gauze snout wipes and gold standard polyester-tipped nasal swabs were collected from 553 pigs representing 29 agricultural fairs and the qualitative results of rRT-PCR and viral isolation were compared. Results and Conclusions Viral recoveries from potential snout wipe materials ranged from 0·26 to 1·59 log10 TCID50/ml less than that of the positive control in which no substrate was included; rayon/polyester gauze performed significantly worse than the other materials. In the field, snout wipes and nasal swabs had high levels of agreement for both rRT-PCR detection and virus isolation. Although further investigation and refinement of the sampling method is needed, results indicate that snout wipes will facilitate convenient and undisruptive IAV surveillance in pigs at agricultural fairs. PMID:25043408

  20. A simple Pichia pastoris fermentation and downstream processing strategy for making recombinant pandemic Swine Origin Influenza a virus Hemagglutinin protein.

    PubMed

    Athmaram, T N; Singh, Anil Kumar; Saraswat, Shweta; Srivastava, Saurabh; Misra, Princi; Kameswara Rao, M; Gopalan, N; Rao, P V L

    2013-02-01

    The present Influenza vaccine manufacturing process has posed a clear impediment to initiation of rapid mass vaccination against spreading pandemic influenza. New vaccine strategies are therefore needed that can accelerate the vaccine production. Pichia offers several advantages for rapid and economical bulk production of recombinant proteins and, hence, can be attractive alternative for producing an effective influenza HA based subunit vaccine. The recombinant Pichia harboring the transgene was subjected to fed-batch fermentation at 10 L scale. A simple fermentation and downstream processing strategy is developed for high-yield secretory expression of the recombinant Hemagglutinin protein of pandemic Swine Origin Influenza A virus using Pichia pastoris via fed-batch fermentation. Expression and purification were optimized and the expressed recombinant Hemagglutinin protein was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blot and MALDI-TOF analysis. In this paper, we describe a fed-batch fermentation protocol for the secreted production of Swine Influenza A Hemagglutinin protein in the P. pastoris GS115 strain. We have shown that there is a clear relationship between product yield and specific growth rate. The fed-batch fermentation and downstream processing methods optimized in the present study have immense practical application for high-level production of the recombinant H1N1 HA protein in a cost effective way using P. pastoris. PMID:23247902

  1. 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.

  2. Human vs. animal outbreaks of the 2009 swine-origin H1N1 influenza A epidemic.

    PubMed

    Scotch, Matthew; Brownstein, John S; Vegso, Sally; Galusha, Deron; Rabinowitz, Peter

    2011-09-01

    The majority of emerging infectious diseases are zoonotic in origin, including recently emerging influenza viruses such as the 2009 swine-origin H1N1 influenza A epidemic. The epidemic that year affected both human and animal populations as it spread globally. In fact, before the end of 2009, 14 different countries reported H1N1 infected swine. In order to better understand the zoonotic nature of the epidemic and the relationship between human and animal disease surveillance data streams, we compared 2009 reports of H1N1 infection to define the temporal relationship between reported cases in animals and humans. Generally, human cases preceded animal cases at a country-level, supporting the potential of H1N1 infection to be a "reverse zoonosis", and the value of integrating human and animal disease report data.

  3. Mutations in the NS1 protein of swine influenza virus impair anti-interferon activity and confer attenuation in pigs.

    PubMed

    Solórzano, Alicia; Webby, Richard J; Lager, Kelly M; Janke, Bruce H; García-Sastre, Adolfo; Richt, Jürgen A

    2005-06-01

    It has been shown previously that the nonstructural protein NS1 of influenza virus is an alpha/beta interferon (IFN-alpha/beta) antagonist, both in vitro and in experimental animal model systems. However, evidence of this function in a natural host has not yet been obtained. Here we investigated the role of the NS1 protein in the virulence of a swine influenza virus (SIV) isolate in pigs by using reverse genetics. The virulent wild-type A/Swine/Texas/4199-2/98 (TX/98) virus and various mutants encoding carboxy-truncated NS1 proteins were rescued. Growth properties of TX/98 viruses with mutated NS1, induction of IFN in tissue culture, and virulence-attenuation in pigs were analyzed and compared to those of the recombinant wild-type TX/98 virus. Our results indicate that deletions in the NS1 protein decrease the ability of the TX/98 virus to prevent IFN-alpha/beta synthesis in pig cells. Moreover, all NS1 mutant viruses were attenuated in pigs, and this correlated with the amount of IFN-alpha/beta induced in vitro. These data suggest that the NS1 protein of SIV is a virulence factor. Due to their attenuation, NS1-mutated swine influenza viruses might have a great potential as live attenuated vaccine candidates against SIV infections of pigs.

  4. 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

    2012-07-01

    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.

  5. Virulence and Genetic Compatibility of Polymerase Reassortant Viruses Derived from the Pandemic (H1N1) 2009 Influenza Virus and Circulating Influenza A Viruses▿†

    PubMed Central

    Song, Min-Suk; Pascua, Philippe Noriel Q.; Lee, Jun Han; Baek, Yun Hee; Park, Kuk Jin; Kwon, Hyeok-il; Park, Su-Jin; Kim, Chul-Joong; Kim, Hyunggee; Webby, Richard J.; Webster, Robert G.; Choi, Young Ki

    2011-01-01

    Gene mutations and reassortment are key mechanisms by which influenza A virus acquires virulence factors. To evaluate the role of the viral polymerase replication machinery in producing virulent pandemic (H1N1) 2009 influenza viruses, we generated various polymerase point mutants (PB2, 627K/701N; PB1, expression of PB1-F2 protein; and PA, 97I) and reassortant viruses with various sources of influenza viruses by reverse genetics. Although the point mutations produced no significant change in pathogenicity, reassortment between the pandemic A/California/04/09 (CA04, H1N1) and current human and animal influenza viruses produced variants possessing a broad spectrum of pathogenicity in the mouse model. Although most polymerase reassortants had attenuated pathogenicity (including those containing seasonal human H3N2 and high-pathogenicity H5N1 virus segments) compared to that of the parental CA04 (H1N1) virus, some recombinants had significantly enhanced virulence. Unexpectedly, one of the five highly virulent reassortants contained a A/Swine/Korea/JNS06/04(H3N2)-like PB2 gene with no known virulence factors; the other four had mammalian-passaged avian-like genes encoding PB2 featuring 627K, PA featuring 97I, or both. Overall, the reassorted polymerase complexes were only moderately compatible for virus rescue, probably because of disrupted molecular interactions involving viral or host proteins. Although we observed close cooperation between PB2 and PB1 from similar virus origins, we found that PA appears to be crucial in maintaining viral gene functions in the context of the CA04 (H1N1) virus. These observations provide helpful insights into the pathogenic potential of reassortant influenza viruses composed of the pandemic (H1N1) 2009 influenza virus and prevailing human or animal influenza viruses that could emerge in the future. PMID:21507962

  6. Live Attenuated Influenza Vaccine Provides Superior Protection from Heterologous Infection in Pigs with Maternal Antibodies without Inducing Vaccine-Associated Enhanced Respiratory Disease

    PubMed Central

    Ma, Wenjun; Lager, Kelly M.; Richt, Jürgen A.; Janke, Bruce H.; Sandbulte, Matthew R.; Gauger, Philip C.; Loving, Crystal L.; Webby, Richard J.; García-Sastre, Adolfo

    2012-01-01

    Control of swine influenza A virus (IAV) in the United States is hindered because inactivated vaccines do not provide robust cross-protection against the multiple antigenic variants cocirculating in the field. Vaccine efficacy can be limited further for vaccines administered to young pigs that possess maternally derived immunity. We previously demonstrated that a recombinant A/sw/Texas/4199-2/1998 (TX98) (H3N2) virus expressing a truncated NS1 protein is attenuated in swine and has potential for use as an intranasal live attenuated influenza virus (LAIV) vaccine. In the present study, we compared 1 dose of intranasal LAIV with 2 intramuscular doses of TX98 whole inactivated virus (WIV) with adjuvant in weanling pigs with and without TX98-specific maternally derived antibodies (MDA). Pigs were subsequently challenged with wild-type homologous TX98 H3N2 virus or with an antigenic variant, A/sw/Colorado/23619/1999 (CO99) (H3N2). In the absence of MDA, both vaccines protected against homologous TX98 and heterologous CO99 shedding, although the LAIV elicited lower hemagglutination inhibition (HI) antibody titers in serum. The efficacy of both vaccines was reduced by the presence of MDA; however, WIV vaccination of MDA-positive pigs led to dramatically enhanced pneumonia following heterologous challenge, a phenomenon known as vaccine-associated enhanced respiratory disease (VAERD). A single dose of LAIV administered to MDA-positive pigs still provided partial protection from CO99 and may be a safer vaccine for young pigs under field conditions, where dams are routinely vaccinated and diverse IAV strains are in circulation. These results have implications not only for pigs but also for other influenza virus host species. PMID:22811541

  7. Live attenuated influenza vaccine provides superior protection from heterologous infection in pigs with maternal antibodies without inducing vaccine-associated enhanced respiratory disease.

    PubMed

    Vincent, Amy L; Ma, Wenjun; Lager, Kelly M; Richt, Jürgen A; Janke, Bruce H; Sandbulte, Matthew R; Gauger, Philip C; Loving, Crystal L; Webby, Richard J; García-Sastre, Adolfo

    2012-10-01

    Control of swine influenza A virus (IAV) in the United States is hindered because inactivated vaccines do not provide robust cross-protection against the multiple antigenic variants cocirculating in the field. Vaccine efficacy can be limited further for vaccines administered to young pigs that possess maternally derived immunity. We previously demonstrated that a recombinant A/sw/Texas/4199-2/1998 (TX98) (H3N2) virus expressing a truncated NS1 protein is attenuated in swine and has potential for use as an intranasal live attenuated influenza virus (LAIV) vaccine. In the present study, we compared 1 dose of intranasal LAIV with 2 intramuscular doses of TX98 whole inactivated virus (WIV) with adjuvant in weanling pigs with and without TX98-specific maternally derived antibodies (MDA). Pigs were subsequently challenged with wild-type homologous TX98 H3N2 virus or with an antigenic variant, A/sw/Colorado/23619/1999 (CO99) (H3N2). In the absence of MDA, both vaccines protected against homologous TX98 and heterologous CO99 shedding, although the LAIV elicited lower hemagglutination inhibition (HI) antibody titers in serum. The efficacy of both vaccines was reduced by the presence of MDA; however, WIV vaccination of MDA-positive pigs led to dramatically enhanced pneumonia following heterologous challenge, a phenomenon known as vaccine-associated enhanced respiratory disease (VAERD). A single dose of LAIV administered to MDA-positive pigs still provided partial protection from CO99 and may be a safer vaccine for young pigs under field conditions, where dams are routinely vaccinated and diverse IAV strains are in circulation. These results have implications not only for pigs but also for other influenza virus host species. PMID:22811541

  8. Live attenuated influenza vaccine provides superior protection from heterologous infection in pigs with maternal antibodies without inducing vaccine-associated enhanced respiratory disease.

    PubMed

    Vincent, Amy L; Ma, Wenjun; Lager, Kelly M; Richt, Jürgen A; Janke, Bruce H; Sandbulte, Matthew R; Gauger, Philip C; Loving, Crystal L; Webby, Richard J; García-Sastre, Adolfo

    2012-10-01

    Control of swine influenza A virus (IAV) in the United States is hindered because inactivated vaccines do not provide robust cross-protection against the multiple antigenic variants cocirculating in the field. Vaccine efficacy can be limited further for vaccines administered to young pigs that possess maternally derived immunity. We previously demonstrated that a recombinant A/sw/Texas/4199-2/1998 (TX98) (H3N2) virus expressing a truncated NS1 protein is attenuated in swine and has potential for use as an intranasal live attenuated influenza virus (LAIV) vaccine. In the present study, we compared 1 dose of intranasal LAIV with 2 intramuscular doses of TX98 whole inactivated virus (WIV) with adjuvant in weanling pigs with and without TX98-specific maternally derived antibodies (MDA). Pigs were subsequently challenged with wild-type homologous TX98 H3N2 virus or with an antigenic variant, A/sw/Colorado/23619/1999 (CO99) (H3N2). In the absence of MDA, both vaccines protected against homologous TX98 and heterologous CO99 shedding, although the LAIV elicited lower hemagglutination inhibition (HI) antibody titers in serum. The efficacy of both vaccines was reduced by the presence of MDA; however, WIV vaccination of MDA-positive pigs led to dramatically enhanced pneumonia following heterologous challenge, a phenomenon known as vaccine-associated enhanced respiratory disease (VAERD). A single dose of LAIV administered to MDA-positive pigs still provided partial protection from CO99 and may be a safer vaccine for young pigs under field conditions, where dams are routinely vaccinated and diverse IAV strains are in circulation. These results have implications not only for pigs but also for other influenza virus host species.

  9. Comparative pathogenesis of an avian H5N2 and a swine H1N1 influenza virus in pigs.

    PubMed

    De Vleeschauwer, Annebel; Atanasova, Kalina; Van Borm, Steven; van den Berg, Thierry; Rasmussen, Thomas Bruun; Uttenthal, Ase; 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.

  10. Characterization of uncultivable bat influenza virus using a replicative synthetic virus.

    PubMed

    Zhou, Bin; Ma, Jingjiao; Liu, Qinfang; Bawa, Bhupinder; Wang, Wei; Shabman, Reed S; Duff, Michael; Lee, Jinhwa; Lang, Yuekun; Cao, Nan; Nagy, Abdou; Lin, Xudong; Stockwell, Timothy B; Richt, Juergen A; Wentworth, David E; Ma, Wenjun

    2014-10-01

    Bats harbor many viruses, which are periodically transmitted to humans resulting in outbreaks of disease (e.g., Ebola, SARS-CoV). Recently, influenza virus-like sequences were identified in bats; however, the viruses could not be cultured. This discovery aroused great interest in understanding the evolutionary history and pandemic potential of bat-influenza. Using synthetic genomics, we were unable to rescue the wild type bat virus, but could rescue a modified bat-influenza virus that had the HA and NA coding regions replaced with those of A/PR/8/1934 (H1N1). This modified bat-influenza virus replicated efficiently in vitro and in mice, resulting in severe disease. Additional studies using a bat-influenza virus that had the HA and NA of A/swine/Texas/4199-2/1998 (H3N2) showed that the PR8 HA and NA contributed to the pathogenicity in mice. Unlike other influenza viruses, engineering truncations hypothesized to reduce interferon antagonism into the NS1 protein didn't attenuate bat-influenza. In contrast, substitution of a putative virulence mutation from the bat-influenza PB2 significantly attenuated the virus in mice and introduction of a putative virulence mutation increased its pathogenicity. Mini-genome replication studies and virus reassortment experiments demonstrated that bat-influenza has very limited genetic and protein compatibility with Type A or Type B influenza viruses, yet it readily reassorts with another divergent bat-influenza virus, suggesting that the bat-influenza lineage may represent a new Genus/Species within the Orthomyxoviridae family. Collectively, our data indicate that the bat-influenza viruses recently identified are authentic viruses that pose little, if any, pandemic threat to humans; however, they provide new insights into the evolution and basic biology of influenza viruses.

  11. Reassortment Networks and the evolution of pandemic H1N1 swine-origin influenza.

    PubMed

    Bokhari, Shahid H; Pomeroy, Laura W; Janies, Daniel A

    2012-01-01

    Prior research developed Reassortment Networks to reconstruct the evolution of segmented viruses under both reassortment and mutation. We report their application to the swine-origin pandemic H1N1 virus (S-OIV). A database of all influenza A viruses, for which complete genome sequences were available in Genbank by October 2009, was created and dynamic programming was used to compute distances between all corresponding segments. A reassortment network was created to obtain the minimum cost evolutionary paths from all viruses to the exemplar S-OIV A/California/04/2009. This analysis took 35 hours on the Cray Extreme Multithreading (XMT) supercomputer, which has special hardware to permit efficient parallelization. Six specific H1N1/H1N2 bottleneck viruses were identified that almost always lie on minimum cost paths to S-OIV. We conjecture that these viruses are crucial to S-OIV evolution and worthy of careful study from a molecular biology viewpoint. In phylogenetics, ancestors are typically medians that have no functional constraints. In our method, ancestors are not inferred, but rather chosen from previously observed viruses along a path of mutation and reassortment leading to the target virus. This specificity and functional constraint render our results actionable for further experiments in vitro and in vivo. PMID:22076498

  12. Reassortment Networks and the evolution of pandemic H1N1 swine-origin influenza.<