Genetically Diverse Low Pathogenicity Avian Influenza A Virus Subtypes Co-Circulate among Poultry in Bangladesh

PubMed Central

Gerloff, Nancy A.; Khan, Salah Uddin; Zanders, Natosha; Balish, Amanda; Haider, Najmul; Islam, Ausraful; Chowdhury, Sukanta; Rahman, Mahmudur Ziaur; Haque, Ainul; Hosseini, Parviez; Gurley, Emily S.; Luby, Stephen P.; Wentworth, David E.; Donis, Ruben O.; Sturm-Ramirez, Katharine; Davis, C. Todd

2016-01-01

Influenza virus surveillance, poultry outbreak investigations and genomic sequencing were assessed to understand the ecology and evolution of low pathogenicity avian influenza (LPAI) A viruses in Bangladesh from 2007 to 2013. We analyzed 506 avian specimens collected from poultry in live bird markets and backyard flocks to identify influenza A viruses. Virus isolation-positive specimens (n = 50) were subtyped and their coding-complete genomes were sequenced. The most frequently identified subtypes among LPAI isolates were H9N2, H11N3, H4N6, and H1N1. Less frequently detected subtypes included H1N3, H2N4, H3N2, H3N6, H3N8, H4N2, H5N2, H6N1, H6N7, and H7N9. Gene sequences were compared to publicly available sequences using phylogenetic inference approaches. Among the 14 subtypes identified, the majority of viral gene segments were most closely related to poultry or wild bird viruses commonly found in Southeast Asia, Europe, and/or northern Africa. LPAI subtypes were distributed over several geographic locations in Bangladesh, and surface and internal protein gene segments clustered phylogenetically with a diverse number of viral subtypes suggesting extensive reassortment among these LPAI viruses. H9N2 subtype viruses differed from other LPAI subtypes because genes from these viruses consistently clustered together, indicating this subtype is enzootic in Bangladesh. The H9N2 strains identified in Bangladesh were phylogenetically and antigenically related to previous human-derived H9N2 viruses detected in Bangladesh representing a potential source for human infection. In contrast, the circulating LPAI H5N2 and H7N9 viruses were both phylogenetically and antigenically unrelated to H5 viruses identified previously in humans in Bangladesh and H7N9 strains isolated from humans in China. In Bangladesh, domestic poultry sold in live bird markets carried a wide range of LPAI virus subtypes and a high diversity of genotypes. These findings, combined with the seven year

Influenza Vaccine Effectiveness in the Netherlands from 2003/2004 through 2013/2014: The Importance of Circulating Influenza Virus Types and Subtypes

PubMed Central

Dijkstra, Frederika; van Doorn, Eva; Bijlsma, Maarten J.; Donker, Gé A.; de Lange, Marit M. A.; Cadenau, Laura M.; Hak, Eelko; Meijer, Adam

2017-01-01

Influenza vaccine effectiveness (IVE) varies over different influenza seasons and virus (sub)types/lineages. To assess the association between IVE and circulating influenza virus (sub)types/lineages, we estimated the overall and (sub)type specific IVE in the Netherlands. We conducted a test-negative case control study among subjects with influenza-like illness or acute respiratory tract infection consulting the Sentinel Practices over 11 influenza seasons (2003/2004 through 2013/2014) in the Netherlands. The adjusted IVE was estimated using generalized linear mixed modelling and multiple logistic regression. In seven seasons vaccine strains did not match the circulating viruses. Overall adjusted IVE was 40% (95% CI 18 to 56%) and 20% (95% CI -5 to 38%) when vaccine (partially)matched and mismatched the circulating viruses, respectively. When A(H3N2) was the predominant virus, IVE was 38% (95% CI 14 to 55%). IVE against infection with former seasonal A(H1N1) virus was 83% (95% CI 52 to 94%), and with B virus 67% (95% CI 55 to 76%). In conclusion IVE estimates were particularly low when vaccine mismatched the circulating viruses and A(H3N2) was the predominant influenza virus subtype. Tremendous effort is required to improve vaccine production procedure and to explore the factors that influence the IVE against A(H3N2) virus. PMID:28068386

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

PubMed Central

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

2013-01-01

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

Prediction of common epitopes on hemagglutinin of the influenza A virus (H1 subtype).

PubMed

Guo, Chunyan; Xie, Xin; Li, Huijin; Zhao, Penghua; Zhao, Xiangrong; Sun, Jingying; Wang, Haifang; Liu, Yang; Li, Yan; Hu, Qiaoxia; Hu, Jun; Li, Yuan

2015-02-01

Influenza A virus infection is a persistent threat to public health worldwide due to hemagglutinin (HA) variation. Current vaccines against influenza A virus provide immunity to viral isolates similar to vaccine strains. Antibodies against common epitopes provide immunity to diverse influenza virus strains and protect against future pandemic influenza. Therefore, it is vital to analyze common HA antigenic epitopes of influenza virus. In this study, 14 strains of monoclonal antibodies with high sensitivity to common epitopes of influenza virus antigens identified in our previous study were selected as the tool to predict common HA epitopes. The common HA antigenic epitopes were divided into four categories by ELISA blocking experiments, and separately, into three categories according to the preliminary results of computer simulation. Comparison between the results of computer simulations and ELISA blocking experiments indicated that at least two classes of common epitopes are present in influenza virus HA. This study provides experimental data for improving the prediction of HA epitopes of influenza virus (H1 subtype) and the development of a potential universal vaccine as well as a novel approach for the prediction of epitopes on other pathogenic microorganisms. Copyright © 2014 Elsevier Inc. All rights reserved.

Comprehensive global amino acid sequence analysis of PB1F2 protein of influenza A H5N1 viruses and the influenza A virus subtypes responsible for the 20th‐century pandemics

PubMed Central

Pasricha, Gunisha; Mishra, Akhilesh C.; Chakrabarti, Alok K.

2012-01-01

Please cite this paper as: Pasricha et al. (2012) Comprehensive global amino acid sequence analysis of PB1F2 protein of influenza A H5N1 viruses and the Influenza A virus subtypes responsible for the 20th‐century pandemics. Influenza and Other Respiratory Viruses 7(4), 497–505. Background  PB1F2 is the 11th protein of influenza A virus translated from +1 alternate reading frame of PB1 gene. Since the discovery, varying sizes and functions of the PB1F2 protein of influenza A viruses have been reported. Selection of PB1 gene segment in the pandemics, variable size and pleiotropic effect of PB1F2 intrigued us to analyze amino acid sequences of this protein in various influenza A viruses. Methods  Amino acid sequences for PB1F2 protein of influenza A H5N1, H1N1, H2N2, and H3N2 subtypes were obtained from Influenza Research Database. Multiple sequence alignments of the PB1F2 protein sequences of the aforementioned subtypes were used to determine the size, variable and conserved domains and to perform mutational analysis. Results  Analysis showed that 96·4% of the H5N1 influenza viruses harbored full‐length PB1F2 protein. Except for the 2009 pandemic H1N1 virus, all the subtypes of the 20th‐century pandemic influenza viruses contained full‐length PB1F2 protein. Through the years, PB1F2 protein of the H1N1 and H3N2 viruses has undergone much variation. PB1F2 protein sequences of H5N1 viruses showed both human‐ and avian host‐specific conserved domains. Global database of PB1F2 protein revealed that N66S mutation was present only in 3·8% of the H5N1 strains. We found a novel mutation, N84S in the PB1F2 protein of 9·35% of the highly pathogenic avian influenza H5N1 influenza viruses. Conclusions  Varying sizes and mutations of the PB1F2 protein in different influenza A virus subtypes with pandemic potential were obtained. There was genetic divergence of the protein in various hosts which highlighted the host‐specific evolution of the virus

Single Assay for Simultaneous Detection and Differential Identification of Human and Avian Influenza Virus Types, Subtypes, and Emergent Variants

PubMed Central

Metzgar, David; Myers, Christopher A.; Russell, Kevin L.; Faix, Dennis; Blair, Patrick J.; Brown, Jason; Vo, Scott; Swayne, David E.; Thomas, Colleen; Stenger, David A.; Lin, Baochuan; Malanoski, Anthony P.; Wang, Zheng; Blaney, Kate M.; Long, Nina C.; Schnur, Joel M.; Saad, Magdi D.; Borsuk, Lisa A.; Lichanska, Agnieszka M.; Lorence, Matthew C.; Weslowski, Brian; Schafer, Klaus O.; Tibbetts, Clark

2010-01-01

For more than four decades the cause of most type A influenza virus infections of humans has been attributed to only two viral subtypes, A/H1N1 or A/H3N2. In contrast, avian and other vertebrate species are a reservoir of type A influenza virus genome diversity, hosting strains representing at least 120 of 144 combinations of 16 viral hemagglutinin and 9 viral neuraminidase subtypes. Viral genome segment reassortments and mutations emerging within this reservoir may spawn new influenza virus strains as imminent epidemic or pandemic threats to human health and poultry production. Traditional methods to detect and differentiate influenza virus subtypes are either time-consuming and labor-intensive (culture-based) or remarkably insensitive (antibody-based). Molecular diagnostic assays based upon reverse transcriptase-polymerase chain reaction (RT-PCR) have short assay cycle time, and high analytical sensitivity and specificity. However, none of these diagnostic tests determine viral gene nucleotide sequences to distinguish strains and variants of a detected pathogen from one specimen to the next. Decision-quality, strain- and variant-specific pathogen gene sequence information may be critical for public health, infection control, surveillance, epidemiology, or medical/veterinary treatment planning. The Resequencing Pathogen Microarray (RPM-Flu) is a robust, highly multiplexed and target gene sequencing-based alternative to both traditional culture- or biomarker-based diagnostic tests. RPM-Flu is a single, simultaneous differential diagnostic assay for all subtype combinations of type A influenza viruses and for 30 other viral and bacterial pathogens that may cause influenza-like illness. These other pathogen targets of RPM-Flu may co-infect and compound the morbidity and/or mortality of patients with influenza. The informative specificity of a single RPM-Flu test represents specimen-specific viral gene sequences as determinants of virus type, A/HN subtype, virulence

Single assay for simultaneous detection and differential identification of human and avian influenza virus types, subtypes, and emergent variants.

PubMed

Metzgar, David; Myers, Christopher A; Russell, Kevin L; Faix, Dennis; Blair, Patrick J; Brown, Jason; Vo, Scott; Swayne, David E; Thomas, Colleen; Stenger, David A; Lin, Baochuan; Malanoski, Anthony P; Wang, Zheng; Blaney, Kate M; Long, Nina C; Schnur, Joel M; Saad, Magdi D; Borsuk, Lisa A; Lichanska, Agnieszka M; Lorence, Matthew C; Weslowski, Brian; Schafer, Klaus O; Tibbetts, Clark

2010-02-03

For more than four decades the cause of most type A influenza virus infections of humans has been attributed to only two viral subtypes, A/H1N1 or A/H3N2. In contrast, avian and other vertebrate species are a reservoir of type A influenza virus genome diversity, hosting strains representing at least 120 of 144 combinations of 16 viral hemagglutinin and 9 viral neuraminidase subtypes. Viral genome segment reassortments and mutations emerging within this reservoir may spawn new influenza virus strains as imminent epidemic or pandemic threats to human health and poultry production. Traditional methods to detect and differentiate influenza virus subtypes are either time-consuming and labor-intensive (culture-based) or remarkably insensitive (antibody-based). Molecular diagnostic assays based upon reverse transcriptase-polymerase chain reaction (RT-PCR) have short assay cycle time, and high analytical sensitivity and specificity. However, none of these diagnostic tests determine viral gene nucleotide sequences to distinguish strains and variants of a detected pathogen from one specimen to the next. Decision-quality, strain- and variant-specific pathogen gene sequence information may be critical for public health, infection control, surveillance, epidemiology, or medical/veterinary treatment planning. The Resequencing Pathogen Microarray (RPM-Flu) is a robust, highly multiplexed and target gene sequencing-based alternative to both traditional culture- or biomarker-based diagnostic tests. RPM-Flu is a single, simultaneous differential diagnostic assay for all subtype combinations of type A influenza viruses and for 30 other viral and bacterial pathogens that may cause influenza-like illness. These other pathogen targets of RPM-Flu may co-infect and compound the morbidity and/or mortality of patients with influenza. The informative specificity of a single RPM-Flu test represents specimen-specific viral gene sequences as determinants of virus type, A/HN subtype, virulence

Contemporary avian influenza A virus subtype H1, H6, H7, H10, and H15 hemagglutinin genes encode a mammalian virulence factor similar to the 1918 pandemic virus H1 hemagglutinin.

PubMed

Qi, Li; Pujanauski, Lindsey M; Davis, A Sally; Schwartzman, Louis M; Chertow, Daniel S; Baxter, David; Scherler, Kelsey; Hartshorn, Kevan L; Slemons, Richard D; Walters, Kathie-Anne; Kash, John C; Taubenberger, Jeffery K

2014-11-18

Zoonotic avian influenza virus infections may lead to epidemics or pandemics. The 1918 pandemic influenza virus has an avian influenza virus-like genome, and its H1 hemagglutinin was identified as a key mammalian virulence factor. A chimeric 1918 virus expressing a contemporary avian H1 hemagglutinin, however, displayed murine pathogenicity indistinguishable from that of the 1918 virus. Here, isogenic chimeric avian influenza viruses were constructed on an avian influenza virus backbone, differing only by hemagglutinin subtype expressed. Viruses expressing the avian H1, H6, H7, H10, and H15 subtypes were pathogenic in mice and cytopathic in normal human bronchial epithelial cells, in contrast to H2-, H3-, H5-, H9-, H11-, H13-, H14-, and H16-expressing viruses. Mouse pathogenicity was associated with pulmonary macrophage and neutrophil recruitment. These data suggest that avian influenza virus hemagglutinins H1, H6, H7, H10, and H15 contain inherent mammalian virulence factors and likely share a key virulence property of the 1918 virus. Consequently, zoonotic infections with avian influenza viruses bearing one of these hemagglutinins may cause enhanced disease in mammals. Influenza viruses from birds can cause outbreaks in humans and may contribute to the development of pandemics. The 1918 pandemic influenza virus has an avian influenza virus-like genome, and its main surface protein, an H1 subtype hemagglutinin, was identified as a key mammalian virulence factor. In a previous study, a 1918 virus expressing an avian H1 gene was as virulent in mice as the reconstructed 1918 virus. Here, a set of avian influenza viruses was constructed, differing only by hemagglutinin subtype. Viruses with the avian H1, H6, H7, H10, and H15 subtypes caused severe disease in mice and damaged human lung cells. Consequently, infections with avian influenza viruses bearing one of these hemagglutinins may cause enhanced disease in mammals, and therefore surveillance for human infections

Detection of influenza virus types A and B and type A subtypes (H1, H3, and H5) by multiplex polymerase chain reaction.

PubMed

Boonsuk, Pitirat; Payungporn, Sunchai; Chieochansin, Thaweesak; Samransamruajkit, Rujipat; Amonsin, Alongkorn; Songserm, Thaweesak; Chaisingh, Arunee; Chamnanpood, Pornchai; Chutinimitkul, Salin; Theamboonlers, Apiradee; Poovorawan, Yong

2008-07-01

Infections with influenza virus type A and B present serious public health problems on a global scale. However, only influenza A virus has been reported to cause fatal pandemic in many species. To provide suitable clinical management and prevent further virus transmission, efficient and effective clinical diagnosis is essential. Therefore, we developed multiplex PCR assays for detecting influenza types A and B and the subtypes of influenza A virus (H1, H3 and H5). Upon performing multiplex PCR assays with type-specific primer sets, the clearly distinguishable products representing influenza A and B virus were separated by agarose gel electrophoresis. In addition, the subtypes of influenza A virus (H1, H3 and H5), which are most common in humans, can be readily distinguished by PCR with subtype-specific primer sets, yielding PCR products of different sizes depending on which subtype has been amplified. This method was tested on 46 influenza virus positive specimens of avian and mammalian (dog and human) origins collected between 2006 and 2008. The sensitivity of this method, tested against known concentrations of each type and subtype specific plasmid, was established to detect 10(3) copies/microl. The method's specificity was determined by testing against other subtypes of influenza A virus (H2, H4 and H6-H15) and respiratory pathogens commonly found in humans. None of them could be amplified, thus excluding cross reactivity. In conclusion, the multiplex PCR assays developed are advantageous as to rapidity, specificity, and cost effectiveness.

Sialidase-Inhibiting Antibody Titers Correlate with Protection from Heterologous Influenza Virus Strains of the Same Neuraminidase Subtype.

PubMed

Walz, Lisa; Kays, Sarah-Katharina; Zimmer, Gert; von Messling, Veronika

2018-06-20

Immune responses induced by currently licensed inactivated influenza vaccines are mainly directed against the hemagglutinin (HA) glycoprotein, the immunodominant antigen of influenza viruses. The resulting antigenic drift of HA requires frequent updating of the vaccine composition and annual revaccination. On the other hand, the level of antibodies directed against the neuraminidase (NA) glycoprotein, the second major influenza virus antigen, vary greatly. To investigate the potential of the more conserved NA protein for the induction of a subtype-specific protection, vesicular stomatitis virus-based replicons expressing a panel of N1 proteins from prototypic seasonal and pandemic H1N1 strain and human H5N1 and H7N9 isolates were generated. Immunization of mice and ferrets with the replicon carrying the matched N1 protein resulted in robust humoral and cellular immune responses and protected against challenge with the homologous influenza virus with similar efficacy as the matched HA protein, illustrating the potential of the NA protein as vaccine antigen. The extent of protection after immunization with mismatched N1 proteins correlated with the level of cross-reactive sialidase-inhibiting antibody titers. Passive serum transfer experiments in mice confirmed that these functional antibodies determine subtype-specific cross-protection. Our findings illustrate the potential of NA-specific immunity for achieving broader protection against antigenic drift variants or newly emerging viruses carrying the same NA but a different HA subtype. IMPORTANCE Despite the availability of vaccines, annual influenza virus epidemics cause 250,000 to 500,000 deaths worldwide. Currently licensed inactivated vaccines, which are standardized for the amount of the hemagglutinin (HA) antigen, primarily induce strain-specific antibodies whereas the immune response to the neuraminidase (NA) antigen, which is also present on the viral surface, is usually low. Using NA-expressing single

Comprehensive global amino acid sequence analysis of PB1F2 protein of influenza A H5N1 viruses and the influenza A virus subtypes responsible for the 20th-century pandemics.

PubMed

Pasricha, Gunisha; Mishra, Akhilesh C; Chakrabarti, Alok K

2013-07-01

PB1F2 is the 11th protein of influenza A virus translated from +1 alternate reading frame of PB1 gene. Since the discovery, varying sizes and functions of the PB1F2 protein of influenza A viruses have been reported. Selection of PB1 gene segment in the pandemics, variable size and pleiotropic effect of PB1F2 intrigued us to analyze amino acid sequences of this protein in various influenza A viruses. Amino acid sequences for PB1F2 protein of influenza A H5N1, H1N1, H2N2, and H3N2 subtypes were obtained from Influenza Research Database. Multiple sequence alignments of the PB1F2 protein sequences of the aforementioned subtypes were used to determine the size, variable and conserved domains and to perform mutational analysis. Analysis showed that 96·4% of the H5N1 influenza viruses harbored full-length PB1F2 protein. Except for the 2009 pandemic H1N1 virus, all the subtypes of the 20th-century pandemic influenza viruses contained full-length PB1F2 protein. Through the years, PB1F2 protein of the H1N1 and H3N2 viruses has undergone much variation. PB1F2 protein sequences of H5N1 viruses showed both human- and avian host-specific conserved domains. Global database of PB1F2 protein revealed that N66S mutation was present only in 3·8% of the H5N1 strains. We found a novel mutation, N84S in the PB1F2 protein of 9·35% of the highly pathogenic avian influenza H5N1 influenza viruses. Varying sizes and mutations of the PB1F2 protein in different influenza A virus subtypes with pandemic potential were obtained. There was genetic divergence of the protein in various hosts which highlighted the host-specific evolution of the virus. However, studies are required to correlate this sequence variability with the virulence and pathogenicity. © 2012 John Wiley & Sons Ltd.

Highly pathogenic avian influenza virus subtype H5N1 in mute swans (Cygnus olor) in Central Bosnia.

PubMed

Goletić, Teufik; Gagić, Abdulah; Residbegović, Emina; Kustura, Aida; Kavazović, Aida; Savić, Vladimir; Harder, Timm; Starick, Elke; Prasović, Senad

2010-03-01

In order to determine the actual prevalence of avian influenza viruses (AIVs) in wild birds in Bosnia and Herzegovina, extensive surveillance was carried out between October 2005 and April 2006. A total of 394 samples representing 41 bird species were examined for the presence of influenza A virus using virus isolation in embryonated chicken eggs, PCR, and nucleotide sequencing. AIV subtype H5N1 was detected in two mute swans (Cygnus olor). The isolates were determined to be highly pathogenic avian influenza (HPAI) virus and the hemagglutinin sequence was closely similar to A/Cygnus olor/Astrakhan/ Ast05-2-10/2005 (H5N1). This is the first report of HPAI subtype H5N1 in Bosnia and Herzegovina.

Highly pathogenic avian influenza virus subtype H5N1 in Mute swans in the Czech Republic.

PubMed

Nagy, Alexander; Machova, Jirina; Hornickova, Jitka; Tomci, Miroslav; Nagl, Ivan; Horyna, Bedrich; Holko, Ivan

2007-02-25

In order to determine the actual prevalence of avian influenza viruses (AIV) in wild birds in the Czech Republic extensive surveillance was carried out between January and April 2006. A total of 2101 samples representing 61 bird species were examined for the presence of influenza A by using PCR, sequencing and cultivation on chicken embryos. AIV subtype H5N1 was detected in 12 Mute swans (Cygnus olor). The viruses were determined as HPAI (highly pathogenic avian influenza) and the hemagglutinin sequence was closely similar to A/mallard/Italy/835/06 and A/turkey/Turkey/1194/05. Following the first H5N1 case, about 300 wild birds representing 33 species were collected from the outbreak region and tested for the presence of AIV without any positive result. This is the first report of highly pathogenic avian influenza subtype H5N1 in the Czech Republic. The potential role of swan as an effective vector of avian influenza virus is also discussed.

Receptor-Binding Profiles of H7 Subtype Influenza Viruses in Different Host Species

PubMed Central

Gambaryan, Alexandra S.; Matrosovich, Tatyana Y.; Philipp, Jennifer; Munster, Vincent J.; Fouchier, Ron A. M.; Cattoli, Giovanni; Capua, Ilaria; Krauss, Scott L.; Webster, Robert G.; Banks, Jill; Bovin, Nicolai V.; Klenk, Hans-Dieter

2012-01-01

Influenza viruses of gallinaceous poultry and wild aquatic birds usually have distinguishable receptor-binding properties. Here we used a panel of synthetic sialylglycopolymers and solid-phase receptor-binding assays to characterize receptor-binding profiles of about 70 H7 influenza viruses isolated from aquatic birds, land-based poultry, and horses in Eurasia and America. Unlike typical duck influenza viruses with non-H7 hemagglutinin (HA), all avian H7 influenza viruses, irrespective of the host species, displayed a poultry-virus-like binding specificity, i.e., preferential binding to sulfated oligosaccharides Neu5Acα2-3Galβ1-4(6-O-HSO3)GlcNAc and Neu5Acα2-3Galβ1-4(Fucα1-3)(6-O-HSO3)GlcNAc. This phenotype correlated with the unique amino acid sequence of the amino acid 185 to 189 loop of H7 HA and seemed to be dependent on ionic interactions between the sulfate group of the receptor and Lys193 and on the lack of sterical clashes between the fucose residue and Gln222. Many North American and Eurasian H7 influenza viruses displayed weak but detectable binding to the human-type receptor moiety Neu5Acα2-6Galβ1-4GlcNAc, highlighting the potential of H7 influenza viruses for avian-to-human transmission. Equine H7 influenza viruses differed from other viruses by preferential binding to the N-glycolyl form of sialic acid. Our data suggest that the receptor-binding site of contemporary H7 influenza viruses in aquatic and terrestrial birds was formed after the introduction of their common precursor from ducks to a new host, presumably, gallinaceous poultry. The uniformity of the receptor-binding profile of H7 influenza viruses in various wild and domestic birds indicates that there is no strong receptor-mediated host range restriction in birds on viruses with this HA subtype. This notion agrees with repeated interspecies transmission of H7 influenza viruses from aquatic birds to poultry. PMID:22345462

Multiplex RT-PCR and indirect immunofluorescence assays for detection and subtyping of human influenza virus in Tunisia.

PubMed

Ben M'hadheb, Manel; Harrabi, Myriam; Souii, Amira; Jrad-Battikh, Nadia; Gharbi, Jawhar

2015-03-01

Influenza viruses are negative stranded segmented RNA viruses belonging to Orthomyxoviridae family. They are classified into three types A, B, and C. Type A influenza viruses are classified into subtypes according to the antigenic characters of the surface glycoproteins: hemagglutinin (H) and neuraminidase (N). The aim of the present study is to develop a fast and reliable multiplex RT-PCR technique for detecting simultaneously the subtypes A/H1N1 and A/H3N2 of influenza virus. Our study included 398 patients (mean age 30.33 ± 19.92 years) with flu or flu-like syndromes, consulting physicians affiliated with collaborating teams. A multiplex RT-PCR detecting A/H1N1 and A/H3N2 influenza viruses and an examination by indirect immunofluorescence (IFI) were performed. In the optimized conditions, we diagnosed by IFI a viral infection in 90 patients (22.6 %): 85 cases of influenza type A, four cases of influenza type B, and only one case of coinfection with types A and B. An evaluation of the technique was performed on 19 clinical specimens positive in IFI, and we detected eight cases of A/H3N2, five cases of A/H1N1, one case of influenza virus type A which is not an H1N1 nor H3N2, and five negative cases. Multiplex RT-PCR is a sensitive technique allowing an effective and fast diagnosis of respiratory infections caused by influenza viruses in which the optimization often collides with problems of sensibility.

Global avian influenza outbreaks 2010-2016: a systematic review of their distribution, avian species and virus subtype.

PubMed

Chatziprodromidou, Ioanna P; Arvanitidou, Malamatenia; Guitian, Javier; Apostolou, Thomas; Vantarakis, George; Vantarakis, Apostolos

2018-01-25

We conducted a systematic review to investigate avian influenza outbreaks and to explore their distribution, upon avian influenza subtype, country, avian species and other relating details as no comprehensive epidemiological analysis of global avian influenza outbreaks from 2010 to 2016 exists. Data was collated from four databases (Scopus, Web of Science Core Correlation, PubMed and SpringerLink electronic journal) and a global electronic reporting system (ProMED mail), using PRISMA and ORION systematic approaches. One hundred seventy three avian influenza virus outbreaks were identified and included in this review, alongside 198 ProMED mail reports. Our research identified that the majority of the reported outbreaks occurred in 2016 (22.2%). These outbreaks were located in China (13.6%) and referred to commercial poultry farms (56.1%). The most common subtype reported in these outbreaks was H5N1 (38.2%), while almost 82.5% of the subtypes were highly pathogenic avian influenza viruses. There were differences noticed between ProMED mail and the scientific literature screened. Avian influenza virus has been proved to be able to contaminate all types of avian species, including commercial poultry farms, wild birds, backyard domestic animals, live poultry, game birds and mixed poultry. The study focused on wet markets, slaughterhouses, wild habitats, zoos and natural parks, in both developed and developing countries. The impact of avian influenza virus seems disproportionate and could potentially burden the already existing disparities in the public health domain. Therefore, a collaboration between all the involved health sectors is considered to be more than necessary.

Surveillance for influenza virus subtypes H1, H2 and H3 among wild birds in Ukraine in 2006-2012

USDA-ARS?s Scientific Manuscript database

Background: Influenza is one of the most important and unpredictable diseases of humans, other mammals and birds. Influenza virus of H1, H2, and H3 subtypes circulate in humans and cause seasonal influenza. Similar subtypes are also circulating in the natural reservoir, wild aquatic birds, and und...

Virus-like Particles Containing Multiple M2 Extracellular Domains Confer Improved Cross-protection Against Various Subtypes of Influenza Virus

PubMed Central

Kim, Min-Chul; Song, Jae-Min; O, Eunju; Kwon, Young-Man; Lee, Youn-Jeong; Compans, Richard W; Kang, Sang-Moo

2013-01-01

The extracellular domain of M2 (M2e), a small ion channel membrane protein, is well conserved among different human influenza A virus strains. To improve the protective efficacy of M2e vaccines, we genetically engineered a tandem repeat of M2e epitope sequences (M2e5x) of human, swine, and avian origin influenza A viruses, which was expressed in a membrane-anchored form and incorporated in virus-like particles (VLPs). The M2e5x protein with the transmembrane domain of hemagglutinin (HA) was effectively incorporated into VLPs at a several 100-fold higher level than that on influenza virions. Intramuscular immunization with M2e5x VLP vaccines was highly effective in inducing M2e-specific antibodies reactive to different influenza viruses, mucosal and systemic immune responses, and cross-protection regardless of influenza virus subtypes in the absence of adjuvant. Importantly, immune sera were found to be sufficient for conferring protection in naive mice, which was long-lived and cross-protective. Thus, molecular designing and presenting M2e immunogens on VLPs provide a promising platform for developing universal influenza vaccines without using adjuvants. PMID:23247101

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

PubMed

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

2015-03-01

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

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

PubMed Central

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

2018-01-01

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

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

Examining the hemagglutinin subtype diversity among wild duck-origin influenza A viruses using ethanol-fixed cloacal swabs and a novel RT-PCR method.

PubMed

Wang, Ruixue; Soll, Lindsey; Dugan, Vivien; Runstadler, Jonathan; Happ, George; Slemons, Richard D; Taubenberger, Jeffery K

2008-05-25

This study presents an interconnected approach for circumventing two inherent limitations associated with studies defining the natural history of influenza A viruses in wild birds. The first limiting factor is the ability to maintain a cold chain from specimen collection to the laboratory when study sites are in more remote locations. The second limiting factor is the ability to identify all influenza A virus HA subtypes present in an original sample. We report a novel method for molecular subtyping of avian influenza A virus hemagglutinin genes using degenerate primers designed to amplify all known hemagglutinin subtypes. It was shown previously that templates larger than 200 bp were not consistently amplifiable from ethanol-fixed cloacal swabs. For this study, new primer sets were designed within these constraints. This method was used to perform subtyping RT-PCR on 191 influenza RNA-positive ethanol-fixed cloacal swabs obtained from 880 wild ducks in central Alaska in 2005. Seven different co-circulating hemagglutinin subtypes were identified in this study set, including H1, H3, H4, H5, H6, H8, and H12. In addition, 16% of original cloacal samples showed evidence of mixed infection, with samples yielding from two-to-five different hemagglutinin subtypes. This study further demonstrates the complex ecobiology of avian influenza A viruses in wild birds.

Examining the hemagglutinin subtype diversity among wild duck-origin influenza A viruses using ethanol-fixed cloacal swabs and a novel RT-PCR method

PubMed Central

Wang, Ruixue; Soll, Lindsey; Dugan, Vivien; Runstadler, Jonathan; Happ, George; Slemons, Richard D.; Taubenberger, Jeffery K.

2008-01-01

This study presents an interconnected approach for circumventing two inherent limitations associated with studies defining the natural history of influenza A viruses in wild birds. The first limiting factor is the ability to maintain a cold chain from specimen collection to the laboratory when study sites are in more remote locations. The second limiting factor is the ability to identify all influenza A virus HA subtypes present in an original sample. We report a novel method for molecular subtyping of avian influenza A virus hemagglutinin genes using degenerate primers designed to amplify all known hemagglutinin subtypes. It was shown previously that templates larger than 200 bp were not consistently amplifiable from ethanol-fixed cloacal swabs. For this study, new primer sets were designed within these constraints. This method was used to perform subtyping RT-PCR on 191 influenza RNA-positive ethanol-fixed cloacal swabs obtained from 880 wild ducks in central Alaska in 2005. Seven different co-circulating hemagglutinin subtypes were identified in this study set, including H1, H3, H4, H5, H6, H8, and H12. In addition, 16% of original cloacal samples showed evidence of mixed infection, with samples yielding from two-to-five different hemagglutinin subtypes. This study further demonstrates the complex ecobiology of avian influenza A viruses in wild birds. PMID:18308356

Influenza A virus recycling revisited.

PubMed Central

Dowdle, W. R.

1999-01-01

Current textbooks link influenza pandemics to influenza A virus subtypes H2 (1889-91), H3 (1990), H1 (1918-20), H2 (1957-58) and H3 (1968), a pattern suggesting subtype recycling in humans. Since H1 reappeared in 1977, whatever its origin, some workers feel that H2 is the next pandemic candidate. This report reviews the publications on which the concept of influenza A virus subtype recycling is based and concludes that the data are inconsistent with the purported sequence of events. The three influenza pandemics prior to 1957-58 were linked with subtypes through retrospective studies of sera from the elderly, or through seroarchaeology. The pandemic seroarchaeological model for subtype H1 has been validated by the recent recovery of swine virus RNA fragments from persons who died from influenza in 1918. Application of the model to pre-existing H3 antibody among the elderly links the H3 subtype to the pandemic of 1889-91, not that of 1900 as popularly quoted. Application of the model to pre-existing H2 antibody among the elderly fails to confirm that this subtype caused a pandemic in the late 1800's, a finding which is consistent with age-related excess mortality patterns during the pandemics of 1957 (H2) and 1968 (H3). H2 variants should be included in pandemic planning for a number of reasons, but not because of evidence of recycling. It is not known when the next pandemic will occur or which of the 15 (or more) haemagglutinin subtypes will be involved. Effective global surveillance remains the key to influenza preparedness. PMID:10593030

Neuraminidase Subtyping of Avian Influenza Viruses with PrimerHunter-Designed Primers and Quadruplicate Primer Pools

PubMed Central

Huang, Yanyan; Khan, Mazhar; Măndoiu, Ion I.

2013-01-01

We have previously developed a software package called PrimerHunter to design primers for PCR-based virus subtyping. In this study, 9 pairs of primers were designed with PrimerHunter and successfully used to differentiate the 9 neuraminidase (NA) genes of avian influenza viruses (AIVs) in multiple PCR-based assays. Furthermore, primer pools were designed and successfully used to decrease the number of reactions needed for NA subtyping from 9 to 4. The quadruplicate primer-pool method is cost-saving, and was shown to be suitable for the NA subtyping of both cultured AIVs and uncultured AIV swab samples. The primers selected for this study showed excellent sensitivity and specificity in NA subtyping by RT-PCR, SYBR green-based Real-time PCR and Real-time RT-PCR methods. AIV RNA of 2 to 200 copies (varied by NA subtypes) could be detected by these reactions. No unspecific amplification was displayed when detecting RNAs of other avian infectious viruses such as Infectious bronchitis virus, Infectious bursal disease virus and Newcastle disease virus. In summary, this study introduced several sensitive and specific PCR-based assays for NA subtyping of AIVs and also validated again the effectiveness of the PrimerHunter tool for the design of subtyping primers. PMID:24312367

Co-infection with Influenza Viruses and Influenza-Like Virus During the 2015/2016 Epidemic Season.

PubMed

Szymański, K; Cieślak, K; Kowalczyk, D; Brydak, L B

2017-01-01

Concerning viral infection of the respiratory system, a single virus can cause a variety of clinical symptoms and the same set of symptoms can be caused by different viruses. Moreover, infection is often caused by a combination of viruses acting at the same time. The present study demonstrates, using multiplex RT-PCR and real-time qRT-PCR, that in the 2015/2016 influenza season, co-infections were confirmed in patients aged 1 month to 90 years. We found 73 co-infections involving influenza viruses, 17 involving influenza viruses and influenza-like viruses, and six involving influenza-like viruses. The first type of co-infections above mentioned was the most common, amounting to 51 cases, with type A and B viruses occurring simultaneously. There also were four cases of co-infections with influenza virus A/H1N1/pdm09 and A/H1N1/ subtypes and two cases with A/H1N1/pdm09 and A/H3N2/ subtypes. The 2015/2016 epidemic season was characterized by a higher number of confirmed co-infections compared with the previous seasons. Infections by more than one respiratory virus were most often found in children and in individuals aged over 65.

Subtype-Specific Influenza A Virus Antibodies in Canada Geese (Branta canadensis)

PubMed Central

Kistler, Whitney M.; Stallknecht, David E.; DeLiberto, Thomas J.; Van Why, Kyle; Yabsley, Michael J.

2015-01-01

Historically, surveillance for influenza A viruses (IAVs) in wild birds has relied on viral detection assays. This was largely due to poor performance of serological assays in wild birds; however, recently developed commercial serological assays have improved the ability to detect IAV antibodies in wild birds. Serological surveillance for IAV antibodies in Canada geese (Branta canadensis) has shown that, despite a low prevalence of virus isolations, Canada geese are frequently exposed to IAVs and that exposure increases with latitude, which follows virus isolation prevalence patterns observed in dabbling ducks. The objectives of this study were to further evaluate IAV antibodies in Canada geese using a subtype-specific serological assay to determine if Canada geese are exposed to subtypes that commonly circulate in dabbling ducks. We collected serum samples from Canada geese in Minnesota, New Jersey, Pennsylvania, and Wisconsin and tested for antibodies to IAVs using a blocking ELISA. Positive samples were further tested by hemagglutination inhibition for 10 hemagglutinin IAV subtypes (H1–H10). Overall, we detected antibodies to NP in 24% (714/2,919) of geese. Antibodies to H3, H4, H5, and H6 subtypes predominated, with H5 being detected most frequently. A decrease in H5 HI antibody prevalence and titers was observed from 2009 to 2012. We also detected similar exposure pattern in Canada geese from New Jersey, Minnesota, Washington and Wisconsin. Based on the published literature, H3, H4, and H6 viruses are the most commonly reported IAVs from dabbling ducks. These results indicate that Canada geese also are frequently exposed to viruses of the same HA subtypes; however, the high prevalence of antibodies to H5 viruses was not expected as H5 IAVs are generally not well represented in reported isolates from ducks. PMID:25845755

Active Surveillance for Avian Influenza Virus, Egypt, 2010–2012

PubMed Central

Kandeil, Ahmed; El-Shesheny, Rabeh; Kayed, Ahmed S.; Gomaa, Mokhtar M.; Maatouq, Asmaa M.; Shehata, Mahmoud M.; Moatasim, Yassmin; Bagato, Ola; Cai, Zhipeng; Rubrum, Adam; Kutkat, Mohamed A.; McKenzie, Pamela P.; Webster, Robert G.; Webby, Richard J.; Ali, Mohamed A.

2014-01-01

Continuous circulation of influenza A(H5N1) virus among poultry in Egypt has created an epicenter in which the viruses evolve into newer subclades and continue to cause disease in humans. To detect influenza viruses in Egypt, since 2009 we have actively surveyed various regions and poultry production sectors. From August 2010 through January 2013, >11,000 swab samples were collected; 10% were positive by matrix gene reverse transcription PCR. During this period, subtype H9N2 viruses emerged, cocirculated with subtype H5N1 viruses, and frequently co-infected the same avian host. Genetic and antigenic analyses of viruses revealed that influenza A(H5N1) clade 2.2.1 viruses are dominant and that all subtype H9N2 viruses are G1-like. Cocirculation of different subtypes poses concern for potential reassortment. Avian influenza continues to threaten public and animal health in Egypt, and continuous surveillance for avian influenza virus is needed. PMID:24655395

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

PubMed Central

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

2014-01-01

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

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.

Avian influenza viruses in humans.

PubMed

Malik Peiris, J S

2009-04-01

Past pandemics arose from low pathogenic avian influenza (LPAI) viruses. In more recent times, highly pathogenic avian influenza (HPAI) H5N1, LPAI H9N2 and both HPAI and LPAI H7 viruses have repeatedly caused zoonotic disease in humans. Such infections did not lead to sustained human-to-human transmission. Experimental infection of human volunteers and seroepidemiological studies suggest that avian influenza viruses of other subtypes may also infect humans. Viruses of the H7 subtype appear to have a predilection to cause conjunctivitis and influenza-like illness (ILI), although HPAI H7N7 virus has also caused fatal respiratory disease. Low pathogenic H9N2 viruses have caused mild ILI and its occurrence may be under-recognised for this reason. In contrast, contemporary HPAI H5N1 viruses are exceptional in their virulence for humans and differ from human seasonal influenza viruses in their pathogenesis. Patients have a primary viral pneumonia progressing to acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome. Over 380 human cases have been confirmed to date, with an overall case fatality of 63%. The zoonotic transmission of avian influenza is a rare occurrence, butthe greater public health concern is the adaptation of such viruses to efficient human transmission, which could lead to a pandemic. A better understanding of the ecology of avian influenza viruses and the biological determinants of transmissibility and pathogenicity in humans is important for pandemic preparedness.

A simplified Sanger sequencing method for full genome sequencing of multiple subtypes of human influenza A viruses.

PubMed

Deng, Yi-Mo; Spirason, Natalie; Iannello, Pina; Jelley, Lauren; Lau, Hilda; Barr, Ian G

2015-07-01

Full genome sequencing of influenza A viruses (IAV), including those that arise from annual influenza epidemics, is undertaken to determine if reassorting has occurred or if other pathogenic traits are present. Traditionally IAV sequencing has been biased toward the major surface glycoproteins haemagglutinin and neuraminidase, while the internal genes are often ignored. Despite the development of next generation sequencing (NGS), many laboratories are still reliant on conventional Sanger sequencing to sequence IAV. To develop a minimal and robust set of primers for Sanger sequencing of the full genome of IAV currently circulating in humans. A set of 13 primer pairs was designed that enabled amplification of the six internal genes of multiple human IAV subtypes including the recent avian influenza A(H7N9) virus from China. Specific primers were designed to amplify the HA and NA genes of each IAV subtype of interest. Each of the primers also incorporated a binding site at its 5'-end for either a forward or reverse M13 primer, such that only two M13 primers were required for all subsequent sequencing reactions. This minimal set of primers was suitable for sequencing the six internal genes of all currently circulating human seasonal influenza A subtypes as well as the avian A(H7N9) viruses that have infected humans in China. This streamlined Sanger sequencing protocol could be used to generate full genome sequence data more rapidly and easily than existing influenza genome sequencing protocols. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Influenza A virus subtypes in wild birds in North-Eastern Spain (Catalonia).

PubMed

Busquets, Núria; Alba, Anna; Napp, Sebastián; Sánchez, Azucena; Serrano, Erika; Rivas, Raquel; Núñez, José I; Majó, Natàlia

2010-04-01

Since the spread of H5N1 highly pathogenic avian influenza virus in 2005, many surveillance programmes have been initiated in poultry and wild birds worldwide. This study describes for the first time the detection of different subtypes of avian influenza viruses (AIV) in wild birds in the West Mediterranean area (Catalonia, North-Eastern Spain). During a 3-year period (from mid-2006 to mid-2009), 1374 birds from 16 different families were examined, and a total of 62 AIV were detected by means of a real-time reverse transcriptase PCR assay. AIV were more frequently detected in Anatidae, Phoenicopteridae, Rallidae and Laridae families. Of the 62 positive samples, 28 AIV could be isolated in embryonated eggs. All isolates were subtyped by haemagglutinin and neuraminidase inhibition techniques and 10 different haemagglutinins (HA) and 7 neuraminidases (NA) were found in 13 different subtype combinations. The most common combinations were H4N6 (22.2%) and H1N1 (18.5%). The HA and NA gene sequences of different AIV subtypes were compared and aligned with those available AIV strains from genome databases. Our studies on AIV phylogenetic analysis revealed that all AIV genes sequenced from wild birds in North-Eastern Spain clustered within Eurasian avian clades, including the sequences of H8, N4 and N5 genes analyzed for the first time in Europe. The results contribute to the understanding of AIV in the Mediterranean area and in Europe. Copyright 2009 Elsevier B.V. All rights reserved.

Rapid detection of avian influenza virus a and subtype H5N1 by single step multiplex reverse transcription-polymerase chain reaction.

PubMed

Wei, Hui-Ling; Bai, Gui-Rong; Mweene, Aaron S; Zhou, Ying-Chun; Cong, Yan-Long; Pu, Juan; Wang, Shuai; Kida, Hiroshi; Liu, Jin-Hua

2006-06-01

Outbreaks of H5N1 highly pathogenic avian influenza (HPAI) virus caused great economic losses to the poultry industry and resulted in human deaths in Thailand and Viet Nam in 2004. Rapid typing and subtyping of H5N1 viruses, especially from clinical specimens, are desirable for taking prompt control measures to prevent the spread of the disease. Here, we developed a set of oligonucleotide primers able to detect, type and subtype H5 and N1 influenza viruses in a single step multiplex reverse transcription-polymerase chain reaction (RT-PCR). RNA was extracted from allantoic fluid or from specimens with guanidinium isothiocyanate reagent. Reverse transcription and PCR were carried out with a mixture of primers specific for influenza viruses of type A, subtype H5 and N1 in a single reaction system under identical conditions. The amplified DNA fragments were analyzed by agarose gel electrophoresis. All the H5N1 viruses tested in the study and the experimental specimens presented three specific bands by the method established here. The results presented here suggest that the method described below is rapid and specific and, therefore, could be valuable in the rapid detection of H5N1 influenza viruses in clinics.

Contemporary Avian Influenza A Virus Subtype H1, H6, H7, H10, and H15 Hemagglutinin Genes Encode a Mammalian Virulence Factor Similar to the 1918 Pandemic Virus H1 Hemagglutinin

PubMed Central

Qi, Li; Pujanauski, Lindsey M.; Davis, A. Sally; Schwartzman, Louis M.; Chertow, Daniel S.; Baxter, David; Scherler, Kelsey; Hartshorn, Kevan L.; Slemons, Richard D.; Walters, Kathie-Anne; Kash, John C.

2014-01-01

ABSTRACT Zoonotic avian influenza virus infections may lead to epidemics or pandemics. The 1918 pandemic influenza virus has an avian influenza virus-like genome, and its H1 hemagglutinin was identified as a key mammalian virulence factor. A chimeric 1918 virus expressing a contemporary avian H1 hemagglutinin, however, displayed murine pathogenicity indistinguishable from that of the 1918 virus. Here, isogenic chimeric avian influenza viruses were constructed on an avian influenza virus backbone, differing only by hemagglutinin subtype expressed. Viruses expressing the avian H1, H6, H7, H10, and H15 subtypes were pathogenic in mice and cytopathic in normal human bronchial epithelial cells, in contrast to H2-, H3-, H5-, H9-, H11-, H13-, H14-, and H16-expressing viruses. Mouse pathogenicity was associated with pulmonary macrophage and neutrophil recruitment. These data suggest that avian influenza virus hemagglutinins H1, H6, H7, H10, and H15 contain inherent mammalian virulence factors and likely share a key virulence property of the 1918 virus. Consequently, zoonotic infections with avian influenza viruses bearing one of these hemagglutinins may cause enhanced disease in mammals. PMID:25406382

Influenza Virus Infection of Marine Mammals.

PubMed

Fereidouni, Sasan; Munoz, Olga; Von Dobschuetz, Sophie; De Nardi, Marco

2016-03-01

Interspecies transmission may play a key role in the evolution and ecology of influenza A viruses. The importance of marine mammals as hosts or carriers of potential zoonotic pathogens such as highly pathogenic H5 and H7 influenza viruses is not well understood. The fact that influenza viruses are some of the few zoonotic pathogens known to have caused infection in marine mammals, evidence for direct transmission of influenza A virus H7N7 subtype from seals to man, transmission of pandemic H1N1 influenza viruses to seals and also limited evidence for long-term persistence of influenza B viruses in seal populations without significant genetic change, makes monitoring of influenza viruses in marine mammal populations worth being performed. In addition, such monitoring studies could be a great tool to better understand the ecology of influenza viruses in nature.

Development of a multiplex probe combination-based one-step real-time reverse transcription-PCR for NA subtype typing of avian influenza virus.

PubMed

Sun, Zhihao; Qin, Tao; Meng, Feifei; Chen, Sujuan; Peng, Daxin; Liu, Xiufan

2017-10-18

Nine influenza virus neuraminidase (NA) subtypes have been identified in poultry and wild birds. Few methods are available for rapid and simple NA subtyping. Here we developed a multiplex probe combination-based one-step real-time reverse transcriptase PCR (rRT-PCR) to detect nine avian influenza virus NA subtypes. Nine primer-probe pairs were assigned to three groups based on the different fluorescent dyes of the probes (FAM, HEX, or Texas Red). Each probe detected only one NA subtype, without cross reactivity. The detection limit was less than 100 EID 50 or 100 copies of cDNA per reaction. Data obtained using this method with allantoic fluid samples isolated from live bird markets and H9N2-infected chickens correlated well with data obtained using virus isolation and sequencing, but was more sensitive. This new method provides a specific and sensitive alternative to conventional NA-subtyping methods.

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

PubMed

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

2015-12-01

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

Rapid detection and subtyping of European swine influenza viruses in porcine clinical samples by haemagglutinin- and neuraminidase-specific tetra- and triplex real-time RT-PCRs.

PubMed

Henritzi, Dinah; Zhao, Na; Starick, Elke; Simon, Gaelle; Krog, Jesper S; Larsen, Lars Erik; Reid, Scott M; Brown, Ian H; Chiapponi, Chiara; Foni, Emanuela; Wacheck, Silke; Schmid, Peter; Beer, Martin; Hoffmann, Bernd; Harder, Timm C

2016-11-01

A diversifying pool of mammalian-adapted influenza A viruses (IAV) with largely unknown zoonotic potential is maintained in domestic swine populations worldwide. The most recent human influenza pandemic in 2009 was caused by a virus with genes originating from IAV isolated from swine. Swine influenza viruses (SIV) are widespread in European domestic pig populations and evolve dynamically. Knowledge regarding occurrence, spread and evolution of potentially zoonotic SIV in Europe is poorly understood. Efficient SIV surveillance programmes depend on sensitive and specific diagnostic methods which allow for cost-effective large-scale analysis. New SIV haemagglutinin (HA) and neuraminidase (NA) subtype- and lineage-specific multiplex real-time RT-PCRs (RT-qPCR) have been developed and validated with reference virus isolates and clinical samples. A diagnostic algorithm is proposed for the combined detection in clinical samples and subtyping of SIV strains currently circulating in Europe that is based on a generic, M-gene-specific influenza A virus RT-qPCR. In a second step, positive samples are examined by tetraplex HA- and triplex NA-specific RT-qPCRs to differentiate the porcine subtypes H1, H3, N1 and N2. Within the HA subtype H1, lineages "av" (European avian-derived), "hu" (European human-derived) and "pdm" (human pandemic A/H1N1, 2009) are distinguished by RT-qPCRs, and within the NA subtype N1, lineage "pdm" is differentiated. An RT-PCR amplicon Sanger sequencing method of small fragments of the HA and NA genes is also proposed to safeguard against failure of multiplex RT-qPCR subtyping. These new multiplex RT-qPCR assays provide adequate tools for sustained SIV monitoring programmes in Europe. © 2016 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of antibodies against the H5 subtype of Influenza A virus in waterfowl

USDA-ARS?s Scientific Manuscript database

Serologic tools for rapid testing of subtype-specific influenza A (IA) virus antibody in wild birds and poultry are limited. In the current study, the ID Screen Influenza H5 Antibody Competition enzyme-linked immunosorbent assay (ELISA) was tested for the detection of antibodies to the H5 subtype o...

Construction of the influenza A virus transmission tree in a college-based population: co-transmission and interactions between influenza A viruses.

PubMed

Zhang, Xu-Sheng; De Angelis, Daniela

2016-01-29

Co-infection of different influenza A viruses is known to occur but how viruses interact within co-infection remains unknown. An outbreak in a college campus during the 2009 pandemic involved two subtypes of influenza A: persons infected with pandemic A/H1N1; persons infected with seasonal A/H3N2 viruses; and persons infected with both at the same time (co-infection). This provides data to analyse the possible interaction between influenza A viruses within co-infection. We extend a statistical inference method designed for outbreaks caused by one virus to that caused by two viruses. The method uses knowledge of which subtype each case is infected with (and whether they were co-infected), contact information and symptom onset date of each case in the influenza outbreak. We then apply it to construct the most likely transmission tree during the outbreak in the college campus. Analysis of the constructed transmission tree shows that the simultaneous presence of the two influenza viruses increases the infectivity and the transmissibility of A/H1N1 virus but whether it changes the infectivity of A/H3N2 is unclear. The estimation also shows that co-transmission of both subtypes from co-infection is low and therefore co-infection cannot be sustained on its own. This study suggests that influenza A viruses within co-infected patients can interact in some ways rather than transmit independently, and this can enhance the spread of influenza A virus infection.

Evidence for seasonal patterns in the relative abundance of avian influenza virus subtypes in blue-winged teal (Anas discors)

USGS Publications Warehouse

Ramey, Andrew M.; Poulson, Rebecca L.; González-Reiche, Ana S.; Wilcox, Benjamin R.; Walther, Patrick; Link, Paul; Carter, Deborah L.; Newsome, George M.; Müller, Maria L.; Berghaus, Roy D.; Perez, Daniel R.; Hall, Jeffrey S.; Stallknecht, David E.

2014-01-01

Seasonal dynamics of influenza A viruses (IAVs) are driven by host density and population immunity. Through an analysis of subtypic data for IAVs isolated from Blue-winged Teal (Anas discors), we present evidence for seasonal patterns in the relative abundance of viral subtypes in spring and summer/autumn.

Evidence for genetic variation of Eurasian avian influenza viruses, subtype H15: The first report of an H15N7 virus

USDA-ARS?s Scientific Manuscript database

Since the first detection of H15 avian influenza viruses (AIVs) in Australia in 1979, only seven H15 strains have been reported. A new H15 AIV was detected in Ukraine in 2010, carrying the unique HA-NA subtype combination H15N7. This virus replicated efficiently in chicken eggs, and antisera against...

Influenza virus isolation.

PubMed

Krauss, Scott; Walker, David; Webster, Robert G

2012-01-01

The isolation of influenza viruses is important for the diagnosis of respiratory diseases in lower animals and humans, for the detection of the infecting agent in surveillance programs, and is an essential element in the development and production of vaccine. Since influenza is caused by a zoonotic virus it is necessary to do surveillance in the reservoir species (aquatic waterfowls), intermediate hosts (quails, pigs), and in affected mammals including humans. Two of the hemagglutinin (HA) subtypes of influenza A viruses (H5 and H7) can evolve into highly pathogenic (HP) strains for gallinaceous poultry; some HP H5 and H7 strains cause lethal infection of humans. In waterfowls, low pathogenic avian influenza (LPAI) isolates are obtained primarily from the cloaca (or feces); in domestic poultry, the virus is more often recovered from the respiratory tract than from cloacal samples; in mammals, the virus is most often isolated from the respiratory tract, and in cases of high pathogenic avian influenza (HPAI) from the blood and internal organs of infected birds. Virus isolation procedures are performed by inoculation of clinical specimens into embryonated eggs (primarily chicken eggs) or onto a variety of primary or continuous tissue culture systems. Successful isolation of influenza virus depends on the quality of the sample and matching the appropriate culture method to the sample type.

Serological evidence of H5-subtype influenza A virus infection in indigenous avian and mammalian species in Korea.

PubMed

Kim, Hye Kwon; Kim, Hee-Jong; Noh, Ji Yeong; Van Phan, Le; Kim, Ji Hyung; Song, Daesub; Na, Woonsung; Kang, Aram; Nguyen, Thi Lan; Shin, Jeong-Hwa; Jeong, Dae Gwin; Yoon, Sun-Woo

2018-03-01

In Korea, H5-subtype highly pathogenic avian influenza (HPAI) has caused huge economic losses in poultry farms through outbreaks of H5N1 since 2003, H5N8 since 2013 and H5N6 since 2016. Although it was reported that long-distance migratory birds may play a major role in the global spread of avian influenza viruses (AIVs), transmission from such birds to poultry has not been confirmed. Intermediate hosts in the wild also may be a potential factor in viral transmission. Therefore, a total of 367 serum samples from wild animals were collected near major migratory bird habitats from 2011 to 2016 and tested by AIV-specific blocking ELISA and hemagglutination inhibition (HI) test. Two mammalian and eight avian species were seropositive according to the ELISA test. Among these, two mammalian (Hydropotes inermis and Prionailurus bengalensis) and three avian (Aegypius monachus, Cygnus cygnus, and Bubo bubo) species showed high HI titres (> 1,280) against one or two H5-subtype AIVs. As H. inermis (water deer), P. bengalensis (leopard cat), and B. bubo (Eurasian eagle owl) are indigenous animals in Korea, evidence of H5-subtype AIV in these animals implies that continuous monitoring of indigenous animals should be followed to understand interspecies transmission ecology of H5-subtype influenza viruses.

PLC-γ1 Signaling Plays a Subtype-Specific Role in Postbinding Cell Entry of Influenza A Virus

PubMed Central

Zhu, Liqian; Ly, Hinh

2014-01-01

Host signaling pathways and cellular proteins play important roles in the influenza viral life cycle and can serve as antiviral targets. In this study, we report the engagement of host phosphoinositide-specific phospholipase γ1 (PLC-γ1) in mediating cell entry of influenza virus H1N1 but not H3N2 subtype. Both PLC-γ1-specific inhibitor and short hairpin RNA (shRNA) strongly suppress the replication of H1N1 but not H3N2 viruses in cell culture, suggesting that PLC-γ1 plays an important subtype-specific role in the influenza viral life cycle. Further analyses demonstrate that PLC-γ1 activation is required for viral postbinding cell entry. In addition, H1N1, but not H3N2, infection leads to the phosphorylation of PLC-γ1 at Ser 1248 immediately after infection and independent of viral replication. We have further shown that H1N1-induced PLC-γ1 activation is downstream of epidermal growth factor receptor (EGFR) signaling. Interestingly, both H1N1 and H3N2 infections activate EGFR, but only H1N1 infection leads to PLC-γ1 activation. Taking our findings together, we have identified for the first time the subtype-specific interplay of host PLC-γ1 signaling and H1N1 virus that is critical for viral uptake early in the infection. Our study provides novel insights into how virus interacts with the cellular signaling network by demonstrating that viral determinants can regulate how the host signaling pathways function in virally infected cells. PMID:24155396

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

Molecular Epidemiology and Antigenic Characterization of Seasonal Influenza Viruses Circulating in Nepal.

PubMed

Upadhyay, B P; Ghimire, P; Tashiro, M; Banjara, M R

2017-01-01

Influenza is one of the public health burdens in Nepal and its epidemiology is not clearly understood. The objective of this study was to explore the molecular epidemiology and the antigenic characteristics of the circulating influenza viruses in Nepal. A total of 1495 throat swab specimens were collected from January to December, 2014. Real time PCR assay was used for identification of influenza virus types and subtypes. Ten percent of the positive specimens were randomly selected and inoculated onto Madin-Darby Canine Kidney Epithelial cells (MDCK) for influenza virus isolation. All viruses were characterized by the hemagglutination inhibition (HI) assay. Influenza viruses were detected in 421/1495 (28.2%) specimens. Among positive cases, influenza A virus was detected in 301/421 (71.5%); of which 120 (39.9%) were influenza A/H1N1 pdm09 and 181 (60.1%) were influenza A/H3 subtype. Influenza B viruses were detected in 119/421 (28.3%) specimens. Influenza A/H1N1 pdm09, A/H3 and B viruses isolated in Nepal were antigenically similar to the vaccine strain influenza A/California/07/2009(H1N1pdm09), A/Texas/50/2012(H3N2), A/New York/39/2012(H3N2) and B/Massachusetts/2/2012, respectively. Influenza viruses were reported year-round in different geographical regions of Nepal which was similar to other tropical countries. The circulating influenza virus type and subtypes of Nepal were similar to vaccine candidate virus which could be prevented by currently used influenza vaccine.

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

PubMed Central

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

2017-01-01

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

Detection of Influenza Virus with Specific Subtype by Using Localized Surface Plasmons Excited on a Flat Metal Surface

NASA Astrophysics Data System (ADS)

Ning, Jun; Nagata, Kotaro; Ainai, Akira; Hasegawa, Hideki; Kano, Hiroshi

2013-08-01

We report on a method to determine subtype of influenza viruses by using surface plasmons localized in microscopic region on a flat metal surface. In this method, refractive index variation arisen from interactions between viruses and their monoclonal antibodies is measured. The developed sensor shows stability of refractive index in the order of 10-4 against sample exchange. In our experiment, A/H1N1 viruses are distinguished from A/H3N2 viruses by using monoclonal antibodies immobilized on the metal surface. Since the measurement probe has the volume of ˜6 al, the method has potential to handle multiple subtypes in the measurement of a sample with ultra small volume.

Evolution and ecology of influenza A viruses.

PubMed Central

Webster, R G; Bean, W J; Gorman, O T; Chambers, T M; Kawaoka, Y

1992-01-01

In this review we examine the hypothesis that aquatic birds are the primordial source of all influenza viruses in other species and study the ecological features that permit the perpetuation of influenza viruses in aquatic avian species. Phylogenetic analysis of the nucleotide sequence of influenza A virus RNA segments coding for the spike proteins (HA, NA, and M2) and the internal proteins (PB2, PB1, PA, NP, M, and NS) from a wide range of hosts, geographical regions, and influenza A virus subtypes support the following conclusions. (i) Two partly overlapping reservoirs of influenza A viruses exist in migrating waterfowl and shorebirds throughout the world. These species harbor influenza viruses of all the known HA and NA subtypes. (ii) Influenza viruses have evolved into a number of host-specific lineages that are exemplified by the NP gene and include equine Prague/56, recent equine strains, classical swine and human strains, H13 gull strains, and all other avian strains. Other genes show similar patterns, but with extensive evidence of genetic reassortment. Geographical as well as host-specific lineages are evident. (iii) All of the influenza A viruses of mammalian sources originated from the avian gene pool, and it is possible that influenza B viruses also arose from the same source. (iv) The different virus lineages are predominantly host specific, but there are periodic exchanges of influenza virus genes or whole viruses between species, giving rise to pandemics of disease in humans, lower animals, and birds. (v) The influenza viruses currently circulating in humans and pigs in North America originated by transmission of all genes from the avian reservoir prior to the 1918 Spanish influenza pandemic; some of the genes have subsequently been replaced by others from the influenza gene pool in birds. (vi) The influenza virus gene pool in aquatic birds of the world is probably perpetuated by low-level transmission within that species throughout the year. (vii

[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.

Characterization of a reassortant H11N9 subtype avian influenza virus isolated from bean goose along the East Asian-Australian flyway.

PubMed

Yao, Yanfeng; Shao, Zhiyong; He, Bin; Yang, Wenhai; Chen, Jianjun; Zhang, Tao; Chen, Xiabing; Chen, Jie

2017-02-01

During the surveillance of avian influenza viruses in the Dongxi Lake wetland of Hubei in 2015-2016, an H11N9 avian influenza virus was isolated from a bean goose (Anser fabalis). Phylogenetic analysis showed that the HA gene of this isolate belongs to the North American lineage; however, the NA and the internal genes of the isolate were generated from the Eurasian lineage. This strain had reduced pathogenicity in mice and was capable of replication in the mouse lung without prior adaptation. This is the first report detecting H11N9 subtype influenza virus from migratory birds in central China. These findings highlight the transmission of avian influenza virus along the East Asian-Australian flyway and the need for continuing surveillance in central China.

Structure and receptor binding preferences of recombinant hemagglutinins from avian and human H6 and H10 influenza A virus subtypes.

PubMed

Yang, Hua; Carney, Paul J; Chang, Jessie C; Villanueva, Julie M; Stevens, James

2015-04-01

During 2013, three new avian influenza A virus subtypes, A(H7N9), A(H6N1), and A(H10N8), resulted in human infections. While the A(H7N9) virus resulted in a significant epidemic in China across 19 provinces and municipalities, both A(H6N1) and A(H10N8) viruses resulted in only a few human infections. This study focuses on the major surface glycoprotein hemagglutinins from both of these novel human viruses. The detailed structural and glycan microarray analyses presented here highlight the idea that both A(H6N1) and A(H10N8) virus hemagglutinins retain a strong avian receptor binding preference and thus currently pose a low risk for sustained human infections. Human infections with zoonotic influenza virus subtypes continue to be a great public health concern. We report detailed structural analysis and glycan microarray data for recombinant hemagglutinins from A(H6N1) and A(H10N8) viruses, isolated from human infections in 2013, and compare them with hemagglutinins of avian origin. This is the first structural report of an H6 hemagglutinin, and our results should further the understanding of these viruses and provide useful information to aid in the continuous surveillance of these zoonotic influenza viruses. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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

PubMed

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

2017-04-01

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

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

PubMed Central

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

2017-01-01

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

Isolation and identification of highly pathogenic avian influenza virus subtype H5N1 in peafowl (Pavo cristatus).

PubMed

Ismail, Mahmoud Moussa; Khan, Owais Ahmed; Cattoli, Giovanni; Lu, Huaguang

2010-03-01

An outbreak of highly pathogenic avian influenza (HPAI) virus subtype H5N1 was first diagnosed in a "backyard" flock of peafowl (Pavo cristatus) raised on palace premises in the Kingdom of Saudi Arabia in December 3, 2007. The flock consisted of 40 peafowl, and their ages ranged from 3 to 5 years old. Affected birds suffered from depression, anorexia, and white diarrhea. Four dead birds were submitted for HPAI diagnosis at the Central Veterinary Diagnostic Laboratory in Riyadh. Brain and liver tissues and tracheal and cloacal swabs were taken from the dead birds and processed for a real-time reverse transcriptase (RT)-PCR test and virus isolation in specific-pathogen-free embryonating chicken eggs. The H5N1 subtype of avian influenza virus was isolated from the four dead birds and identified by a real-time RT-PCR before and after egg inoculation. The virus isolates were characterized as HPAI H5N1 virus by sequencing analysis. Phylogenetic comparisons revealed that the H5N1 viruses isolated from peafowl belong to the genetic clade 2.2 according to the World Health Organization nomenclature. The peafowl H5N1 virus falls into 2.2.2 sublineage II and clusters with the H5N1 viruses isolated from poultry in Saudi Arabia in 2007-08.

H5N1 influenza viruses: outbreaks and biological properties

PubMed Central

Neumann, Gabriele; Chen, Hualan; Gao, George F; Shu, Yuelong; Kawaoka, Yoshihiro

2010-01-01

All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties. PMID:19884910

Pandemic Threat Posed by Avian Influenza A Viruses

PubMed Central

Horimoto, Taisuke; Kawaoka, Yoshihiro

2001-01-01

Influenza pandemics, defined as global outbreaks of the disease due to viruses with new antigenic subtypes, have exacted high death tolls from human populations. The last two pandemics were caused by hybrid viruses, or reassortants, that harbored a combination of avian and human viral genes. Avian influenza viruses are therefore key contributors to the emergence of human influenza pandemics. In 1997, an H5N1 influenza virus was directly transmitted from birds in live poultry markets in Hong Kong to humans. Eighteen people were infected in this outbreak, six of whom died. This avian virus exhibited high virulence in both avian and mammalian species, causing systemic infection in both chickens and mice. Subsequently, another avian virus with the H9N2 subtype was directly transmitted from birds to humans in Hong Kong. Interestingly, the genes encoding the internal proteins of the H9N2 virus are genetically highly related to those of the H5N1 virus, suggesting a unique property of these gene products. The identification of avian viruses in humans underscores the potential of these and similar strains to produce devastating influenza outbreaks in major population centers. Although highly pathogenic avian influenza viruses had been identified before the 1997 outbreak in Hong Kong, their devastating effects had been confined to poultry. With the Hong Kong outbreak, it became clear that the virulence potential of these viruses extended to humans. PMID:11148006

Influenza A virus among the hospitalized young children with acute respiratory infection. Is influenza A co infected with respiratory syncytial virus?

PubMed Central

Alavi, Seyed Mohammad; Makvandi, Manoochehr; Najafi-Fard, Saied; Alavi, Leila

2012-01-01

Background: Both influenza A virus (IAV) and respiratory syncytial virus (RSV) cause acute respiratory infection (ARI) in infants and young children. This study was conducted to determine Influenza A virus and its co infection with RSV among the hospitalized children with ARI. Methods: A total of 153 throat samples of the hospitalized young children aged between below one year and 5 years with the clinical signs of ARI were collected from the different hospitals in Khuzestan from June 2009 to April 2010. The samples were tested for Influenza A viruses by real time PCR. Positive IAV samples were tested for influenza A sub type H1N1 and for RSV by the nested PCR. Results: In this study, from the total 153 samples, 35 samples (22.9%) including 15 (42.8%) females and 20 (57.2%) males were positive for influenza A viruses. From the 35 positive samples for IAV, 14 were positive for swine H1N1 subtype. All the positive samples for influenza showed negative for RSV infection which revealed no coinfection with RSV. The prevalence of influenza A among age/sex groups was not significant. Conclusion: Influenza A is a prevalent viral agent isolated from young children with ARI. Influenza A subtype H1N1 was accounted for the 40 percent all laboratory-proven diagnoses of influenza in 2009. No evidence of coinfection of influenza A and RSV has been observed in the present study. PMID:24009929

Serological evidence of influenza A viruses in frugivorous bats from Africa.

PubMed

Freidl, Gudrun Stephanie; Binger, Tabea; Müller, Marcel Alexander; de Bruin, Erwin; van Beek, Janko; Corman, Victor Max; Rasche, Andrea; Drexler, Jan Felix; Sylverken, Augustina; Oppong, Samuel K; Adu-Sarkodie, Yaw; Tschapka, Marco; Cottontail, Veronika M; Drosten, Christian; Koopmans, Marion

2015-01-01

Bats are likely natural hosts for a range of zoonotic viruses such as Marburg, Ebola, Rabies, as well as for various Corona- and Paramyxoviruses. In 2009/10, researchers discovered RNA of two novel influenza virus subtypes--H17N10 and H18N11--in Central and South American fruit bats. The identification of bats as possible additional reservoir for influenza A viruses raises questions about the role of this mammalian taxon in influenza A virus ecology and possible public health relevance. As molecular testing can be limited by a short time window in which the virus is present, serological testing provides information about past infections and virus spread in populations after the virus has been cleared. This study aimed at screening available sera from 100 free-ranging, frugivorous bats (Eidolon helvum) sampled in 2009/10 in Ghana, for the presence of antibodies against the complete panel of influenza A haemagglutinin (HA) types ranging from H1 to H18 by means of a protein microarray platform. This technique enables simultaneous serological testing against multiple recombinant HA-types in 5 μl of serum. Preliminary results indicate serological evidence against avian influenza subtype H9 in about 30% of the animals screened, with low-level cross-reactivity to phylogenetically closely related subtypes H8 and H12. To our knowledge, this is the first report of serological evidence of influenza A viruses other than H17 and H18 in bats. As avian influenza subtype H9 is associated with human infections, the implications of our findings from a public health context remain to be investigated.

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

PubMed

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

2014-08-08

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

Replication of 2 subtypes of low-pathogenicity avian influenza virus of duck and gull origins in experimentally infected Mallard ducks.

PubMed

Daoust, P-Y; van de Bildt, M; van Riel, D; van Amerongen, G; Bestebroer, T; Vanderstichel, R; Fouchier, R A M; Kuiken, T

2013-05-01

Many subtypes of low-pathogenicity avian influenza (LPAI) virus circulate in wild bird reservoirs, but their prevalence may vary among species. We aimed to compare by real-time reverse-transcriptase polymerase chain reaction, virus isolation, histology, and immunohistochemistry the distribution and pathogenicity of 2 such subtypes of markedly different origins in Mallard ducks (Anas platyrhynchos): H2N3 isolated from a Mallard duck and H13N6 isolated from a Ring-billed Gull (Larus delawarensis). Following intratracheal and intraesophageal inoculation, neither virus caused detectable clinical signs, although H2N3 virus infection was associated with a significantly decreased body weight gain during the period of virus shedding. Both viruses replicated in the lungs and air sacs until approximately day 3 after inoculation and were associated with a locally extensive interstitial, exudative, and proliferative pneumonia. Subtype H2N3, but not subtype H13N6, went on to infect the epithelia of the intestinal mucosa and cloacal bursa, where it replicated without causing lesions until approximately day 5 after inoculation. Larger quantities of subtype H2N3 virus were detected in cloacal swabs than in pharyngeal swabs. The possible clinical significance of LPAI virus-associated pulmonary lesions and intestinal tract infection in ducks deserves further evaluation.

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses.

PubMed

Song, Min-Suk; Marathe, Bindumadhav M; Kumar, Gyanendra; Wong, Sook-San; Rubrum, Adam; Zanin, Mark; Choi, Young-Ki; Webster, Robert G; Govorkova, Elena A; Webby, Richard J

2015-11-01

Human infections with avian influenza viruses are a serious public health concern. The neuraminidase (NA) inhibitors (NAIs) are the frontline anti-influenza drugs and are the major option for treatment of newly emerging influenza. Therefore, it is essential to identify the molecular markers of NAI resistance among specific NA subtypes of avian influenza viruses to help guide clinical management. NAI-resistant substitutions in NA subtypes other than N1 and N2 have been poorly studied. Here, we identified NA amino acid substitutions associated with NAI resistance among influenza viruses of N3, N7, and N9 subtypes which have been associated with zoonotic transmission. We applied random mutagenesis and generated recombinant influenza viruses carrying single or double NA substitution(s) with seven internal genes from A/Puerto Rico/8/1934 (H1N1) virus. In a fluorescence-based NA inhibition assay, we identified three categories of NA substitutions associated with reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir): (i) novel subtype-specific substitutions in or near the enzyme catalytic site (R152W, A246T, and D293N, N2 numbering), (ii) subtype-independent substitutions (E119G/V and/or D and R292K), and (iii) substitutions previously reported in other subtypes (Q136K, I222M, and E276D). Our data show that although some markers of resistance are present across NA subtypes, other subtype-specific markers can only be determined empirically. The number of humans infected with avian influenza viruses is increasing, raising concerns of the emergence of avian influenza viruses resistant to neuraminidase (NA) inhibitors (NAIs). Since most studies have focused on NAI-resistance in human influenza viruses, we investigated the molecular changes in NA that could confer NAI resistance in avian viruses grown in immortalized monolayer cells, especially those of the N3, N7, and N9 subtypes, which have caused human infections. We identified not only numerous NAI

Effectiveness of monovalent 2009 pandemic influenza A virus subtype H1N1 and 2010-2011 trivalent inactivated influenza vaccines in Wisconsin during the 2010-2011 influenza season.

PubMed

Bateman, Allen C; Kieke, Burney A; Irving, Stephanie A; Meece, Jennifer K; Shay, David K; Belongia, Edward A

2013-04-15

The 2009 influenza A virus subtype H1N1 (A[H1N1]pdm09) did not exhibit antigenic drift during the 2010-2011 influenza season, providing an opportunity to investigate the duration of protection after vaccination. We estimated the independent effects of 2010-2011 seasonal trivalent inactivated influenza vaccine (TIV) and A(H1N1)pdm09 vaccine for preventing medically attended influenza A virus infection during the 2010-2011 season. Individuals were tested for influenza A virus by real-time reverse transcription polymerase chain reaction (rRT-PCR) after a clinical encounter for acute respiratory illness. Case-control analyses compared participants with rRT-PCR-confirmed influenza A virus infection and test-negative controls. Vaccine effectiveness was estimated separately for monovalent pandemic vaccine and TIV and was calculated as 100 × [1 - adjusted odds ratio], where the odds ratio was adjusted for potential confounders. The effectiveness of TIV against influenza A virus infection was 63% (95% confidence interval [CI], 37%-78%). The effectiveness of TIV against A(H1N1)pdm09 infection was 77% (95% CI, 44%-90%). Monovalent vaccine administered between October 2009 and April 2010 was not protective during the 2010-2011 season, with an effectiveness of -1% (95% CI, -146% to 59%) against A(H1N1)pdm09 infection.  Monovalent vaccine provided no sustained protection against A(H1N1)pdm09 infection during the 2010-2011 season. This waning effectiveness supports the need for annual revaccination, even in the absence of antigenic drift in A(H1N1)pdm09.

The public health impact of avian influenza viruses.

PubMed

Katz, J M; Veguilla, V; Belser, J A; Maines, T R; Van Hoeven, N; Pappas, C; Hancock, K; Tumpey, T M

2009-04-01

Influenza viruses with novel hemagglutinin and 1 or more accompanying genes derived from avian influenza viruses sporadically emerge in humans and have the potential to result in a pandemic if the virus causes disease and spreads efficiently in a population that lacks immunity to the novel hemagglutinin. Since 1997, multiple avian influenza virus subtypes have been transmitted directly from domestic poultry to humans and have caused a spectrum of human disease, from asymptomatic to severe and fatal. To assess the pandemic risk that avian influenza viruses pose, we have used multiple strategies to better understand the capacity of avian viruses to infect, cause disease, and transmit among mammals, including humans. Seroepidemiologic studies that evaluate the frequency and risk of human infection with avian influenza viruses in populations with exposure to domestic or wild birds can provide a better understanding of the pandemic potential of avian influenza subtypes. Investigations conducted in Hong Kong following the first H5N1 outbreak in humans in 1997 determined that exposure to poultry in live bird markets was a key risk factor for human disease. Among poultry workers, butchering and exposure to sick poultry were risk factors for antibody to H5 virus, which provided evidence for infection. A second risk assessment tool, the ferret, can be used to evaluate the level of virulence and potential for host-to-host transmission of avian influenza viruses in this naturally susceptible host. Avian viruses isolated from humans exhibit a level of virulence and transmissibility in ferrets that generally reflects that seen in humans. The ferret model thus provides a means to monitor emerging avian influenza viruses for pandemic risk, as well as to evaluate laboratory-generated reassortants and mutants to better understand the molecular basis of influenza virus transmissibility. Taken together, such studies provide valuable information with which we can assess the public

Simultaneous subtyping and pathotyping of avian influenza viruses in chickens in Taiwan using reverse transcription loop-mediated isothermal amplification and microarray

PubMed Central

WANG, Lih-Chiann; HUANG, Dean; CHEN, Hui-Wen

2016-01-01

The H6N1 avian influenza virus has circulated in Taiwan for more than 40 years. The sporadic activity of low pathogenic H5N2 virus has been noted since 2003, and highly pathogenic H5N2 avian influenza virus has been detected since 2008. Ressortant viruses between H6N1 and H5N2 viruses have become established and enzootic in chickens throughout Taiwan. Outbreaks caused by Novel highly pathogenic H5 avian influenza viruses whose HA genes were closely related to that of the H5N8 virus isolated from ducks in Korea in 2014 were isolated from outbreaks in Taiwan since early 2015. The avian influenza virus infection status is becoming much more complicated in chickens in Taiwan. This necessitates a rapid and simple approach to detect and differentiate the viruses that prevail. H6N1, H5N2 and novel H5 viruses were simultaneously subtyped and pathotyped in this study using reverse transcription loop-mediated isothermal amplification and microarray, with detection limits of 10°, 101 and 10° viral copy numbers, respectively. The microarray signals were read by the naked eye with no expensive equipment needed. The method developed in this study could greatly improve avian influenza virus surveillance efficiency. PMID:27086860

Establishment of the cross-clade antigen detection system for H5 subtype influenza viruses using peptide monoclonal antibodies specific for influenza virus H5 hemagglutinin.

PubMed

Takahashi, Hitoshi; Nagata, Shiho; Odagiri, Takato; Kageyama, Tsutomu

2018-04-15

The H5 subtype of highly pathogenic avian influenza (H5 HPAI) viruses is a threat to both animal and human public health and has the potential to cause a serious future pandemic in humans. Thus, specific and rapid detection of H5 HPAI viruses is required for infection control in humans. To develop a simple and rapid diagnostic system to detect H5 HPAI viruses with high specificity and sensitivity, we attempted to prepare monoclonal antibodies (mAbs) that specifically recognize linear epitopes in hemagglutinin (HA) of H5 subtype viruses. Nine mAb clones were obtained from mice immunized with a synthetic partial peptide of H5 HA molecules conserved among various H5 HPAI viruses. The antigen-capture enzyme-linked immunosorbent assay using the most suitable combination of these mAbs, which bound specifically to lysed H5 HA under an optimized detergent condition, was specific for H5 viruses and could broadly detect H5 viruses in multiple different clades. Taken together, these peptide mAbs, which recognize linear epitopes in a highly conserved region of H5 HA, may be useful for specific and highly sensitive detection of H5 HPAI viruses and can help in the rapid diagnosis of human, avian, and animal H5 virus infections. Copyright © 2018 Elsevier Inc. All rights reserved.

Avian influenza virus infections in humans.

PubMed

Wong, Samson S Y; Yuen, Kwok-Yung

2006-01-01

Seroepidemiologic and virologic studies since 1889 suggested that human influenza pandemics were caused by H1, H2, and H3 subtypes of influenza A viruses. If not for the 1997 avian A/H5N1 outbreak in Hong Kong of China, subtype H2 is the likely candidate for the next pandemic. However, unlike previous poultry outbreaks of highly pathogenic avian influenza due to H5 that were controlled by depopulation with or without vaccination, the presently circulating A/H5N1 genotype Z virus has since been spreading from Southern China to other parts of the world. Migratory birds and, less likely, bird trafficking are believed to be globalizing the avian influenza A/H5N1 epidemic in poultry. More than 200 human cases of avian influenza virus infection due to A/H5, A/H7, and A/H9 subtypes mainly as a result of poultry-to-human transmission have been reported with a > 50% case fatality rate for A/H5N1 infections. A mutant or reassortant virus capable of efficient human-to-human transmission could trigger another influenza pandemic. The recent isolation of this virus in extrapulmonary sites of human diseases suggests that the high fatality of this infection may be more than just the result of a cytokine storm triggered by the pulmonary disease. The emergence of resistance to adamantanes (amantadine and rimantadine) and recently oseltamivir while H5N1 vaccines are still at the developmental stage of phase I clinical trial are causes for grave concern. Moreover, the to-be pandemic strain may have little cross immunogenicity to the presently tested vaccine strain. The relative importance and usefulness of airborne, droplet, or contact precautions in infection control are still uncertain. Laboratory-acquired avian influenza H7N7 has been reported, and the laboratory strains of human influenza H2N2 could also be the cause of another pandemic. The control of this impending disaster requires more research in addition to national and international preparedness at various levels. The

Weighing serological evidence of human exposure to animal influenza viruses - a literature review.

PubMed

Sikkema, Reina Saapke; Freidl, Gudrun Stephanie; de Bruin, Erwin; Koopmans, Marion

2016-11-03

Assessing influenza A virus strains circulating in animals and their potential to cross the species barrier and cause human infections is important to improve human influenza surveillance and preparedness. We reviewed studies describing serological evidence of human exposure to animal influenza viruses. Comparing serological data is difficult due to a lack of standardisation in study designs and in laboratory methods used in published reports. Therefore, we designed a scoring system to assess and weigh specificity of obtained serology results in the selected articles. Many studies report reliable evidence of antibodies to swine influenza viruses among persons occupationally exposed to pigs. Most avian influenza studies target H5, H7 and H9 subtypes and most serological evidence of human exposure to avian influenza viruses is reported for these subtypes. Avian influenza studies receiving a low grade in this review often reported higher seroprevalences in humans compared with studies with a high grade. Official surveillance systems mainly focus on avian H5 and H7 viruses. Swine influenza viruses and avian subtypes other than H5 and H7 (emphasising H9) should be additionally included in official surveillance systems. Surveillance efforts should also be directed towards understudied geographical areas, such as Africa and South America. This article is copyright of The Authors, 2016.

The rapid identification of human influenza neuraminidase N1 and N2 subtypes by ELISA.

PubMed

Barr, I G; McCaig, M; Durrant, C; Shaw, R

2006-11-10

An ELISA assay was developed to allow the rapid and accurate identification of human influenza A N1 and N2 neuraminidases. Initial testing using a fetuin pre-coating of wells correctly identified 81.7% of the neuraminidase type from a series of human A(H1N1), A(H1N2) and A(H3N2) viruses. This result could be improved to detect the neuraminidase subtype of almost all human influenza A viruses from a large panel of viruses isolated from 2000 to 2005, if the fetuin pre-coating was removed and the viruses were coated directly onto wells. This method is simple, rapid and can be used to screen large numbers of currently circulating human influenza A viruses for their neurraminidase subtype and is a good alternative to RT-PCR.

Sampling strategies and biodiversity of influenza A subtypes in wild birds

USGS Publications Warehouse

Olson, Sarah H.; Parmley, Jane; Soos, Catherine; Gilbert, Martin; Latore-Margalef, Neus; Hall, Jeffrey S.; Hansbro, Phillip M.; Leighton, Frank; Munster, Vincent; Joly, Damien

2014-01-01

Wild aquatic birds are recognized as the natural reservoir of avian influenza A viruses (AIV), but across high and low pathogenic AIV strains, scientists have yet to rigorously identify most competent hosts for the various subtypes. We examined 11,870 GenBank records to provide a baseline inventory and insight into patterns of global AIV subtype diversity and richness. Further, we conducted an extensive literature review and communicated directly with scientists to accumulate data from 50 non-overlapping studies and over 250,000 birds to assess the status of historic sampling effort. We then built virus subtype sample-based accumulation curves to better estimate sample size targets that capture a specific percentage of virus subtype richness at seven sampling locations. Our study identifies a sampling methodology that will detect an estimated 75% of circulating virus subtypes from a targeted bird population and outlines future surveillance and research priorities that are needed to explore the influence of host and virus biodiversity on emergence and transmission.

Complete genome sequence of a novel H9N2 subtype influenza virus FJG9 strain in China reveals a natural reassortant event.

PubMed

Xie, Qingmei; Yan, Zhuanqiang; Ji, Jun; Zhang, Huanmin; Liu, Jun; Sun, Yue; Li, Guangwei; Chen, Feng; Xue, Chunyi; Ma, Jingyun; Bee, Yingzuo

2012-09-01

A/chicken/FJ/G9/09 (FJ/G9) is an H9N2 subtype avian influenza virus (H9N2 AIV) strain causing high morbidity that was isolated from broilers in Fujian Province of China in 2009. FJ/G9 has been used as the vaccine strain against H9N2 AIV infection in Fujian Province of China. Here, we report the complete genome sequence of FJ/G9 with natural six-way reassortment, which is the most complex genotype strain in China and even in the world so far. The present findings will aid in understanding the complexity and diversity of H9N2 subtype avian influenza virus.

Replication and transmission of mammalian-adapted H9 subtype influenza virus in pigs and quail

PubMed Central

Obadan, Adebimpe O.; Kimble, Brian J.; Rajao, Daniela; Lager, Kelly; Santos, Jefferson J. S.; Vincent, Amy

2015-01-01

Influenza A virus is a major pathogen of birds, swine and humans. Strains can jump between species in a process often requiring mutations and reassortment, resulting in outbreaks and, potentially, pandemics. H9N2 avian influenza is predominant in poultry across Asia and occasionally infects humans and swine. Pandemic H1N1 (H1N1pdm) is endemic in humans and swine and has a history of reassortment in pigs. Previous studies have shown the compatibility of H9N2 and H1N1pdm for reassortment in ferrets, a model for human infection and transmission. Here, the effects of ferret adaptation of H9 surface gene segments on the infectivity and transmission in at-risk natural hosts, specifically swine and quail, were analysed. Reassortant H9N1 and H9N2 viruses, carrying seven or six gene segments from H1N1pdm, showed infectivity and transmissibility in swine, unlike the wholly avian H9N2 virus with ferret-adapted surface genes. In quail, only the reassortant H9N2 with the six internal gene segments from the H1N1pdm strain was able to infect and transmit, although less efficiently than the wholly avian H9N2 virus with ferret-adapted surface genes. These results highlight that ferret-adapted mutations on the haemagglutinin of H9 subtype virus do not restrict the ability of the virus to infect swine and quail, and that the ability to transmit in these species depends on the context of the whole virus. As such, this study emphasizes the threat that H9N2 reassortant viruses pose to humans and agricultural species and the importance of the genetic constellation of the virus to its ability to replicate and transmit in natural hosts of influenza. PMID:25986634

A proof-of-principle study to identify suitable vaccine seed candidates to combat introductions of Eurasian lineage H5 and H7 subtype avian influenza viruses.

PubMed

Beato, Maria Serena; Monne, Isabella; Mancin, Marzia; Bertoli, Elena; Capua, Ilaria

2010-10-01

Vaccination against avian influenza (AI) is now included amongst the prevention and control measures recommended by international animal health organizations to combat the disease in poultry. For optimal control of human influenza infections, the antigenic variability within subtypes requires the annual update of seed strains for inclusion in vaccines. The decisions taken are based on serological cross-reactivity of viral strains measured by haemagglutination inhibition (HI) tests. The reason for this is to ensure that the vaccine contains strains that are related antigenically to the current circulating field strain as field viruses evolve or are substituted by variants of distinct antigenicity. Such an annual approach is not viable economically for the poultry industry. In the current study, we have applied a similar HI-based approach to demonstrate, as proof of principle, that cross-reactive strains can be identified. Applying the same approach used by the World Health Organization to investigate antigenic differences among human influenza viruses, we assessed the serological cross-reactivity of a selection of natural H5 and H7 subtype viruses. Analysing HI data, we have identified strains that are cross-reactive and may have the potential to act as seed viruses for future vaccine development. This study should be considered a starting point for a more informed approach to the selection of seed strains for the development of avian influenza vaccines against field infections caused by viruses of H5 and H7 subtypes.

Screening for Neuraminidase Inhibitor Resistance Markers among Avian Influenza Viruses of the N4, N5, N6, and N8 Neuraminidase Subtypes.

PubMed

Choi, Won-Suk; Jeong, Ju Hwan; Kwon, Jin Jung; Ahn, Su Jeong; Lloren, Khristine Kaith S; Kwon, Hyeok-Il; Chae, Hee Bok; Hwang, Jungwon; Kim, Myung Hee; Kim, Chul-Joong; Webby, Richard J; Govorkova, Elena A; Choi, Young Ki; Baek, Yun Hee; Song, Min-Suk

2018-01-01

Several subtypes of avian influenza viruses (AIVs) are emerging as novel human pathogens, and the frequency of related infections has increased in recent years. Although neuraminidase (NA) inhibitors (NAIs) are the only class of antiviral drugs available for therapeutic intervention for AIV-infected patients, studies on NAI resistance among AIVs have been limited, and markers of resistance are poorly understood. Previously, we identified unique NAI resistance substitutions in AIVs of the N3, N7, and N9 NA subtypes. Here, we report profiles of NA substitutions that confer NAI resistance in AIVs of the N4, N5, N6, and N8 NA subtypes using gene-fragmented random mutagenesis. We generated libraries of mutant influenza viruses using reverse genetics (RG) and selected resistant variants in the presence of the NAIs oseltamivir carboxylate and zanamivir in MDCK cells. In addition, two substitutions, H274Y and R292K (N2 numbering), were introduced into each NA gene for comparison. We identified 37 amino acid substitutions within the NA gene, 16 of which (4 in N4, 4 in N5, 4 in N6, and 4 in N8) conferred resistance to NAIs (oseltamivir carboxylate, zanamivir, or peramivir) as determined using a fluorescence-based NA inhibition assay. Substitutions conferring NAI resistance were mainly categorized as either novel NA subtype specific (G/N147V/I, A246V, and I427L) or previously reported in other subtypes (E119A/D/V, Q136K, E276D, R292K, and R371K). Our results demonstrate that each NA subtype possesses unique NAI resistance markers, and knowledge of these substitutions in AIVs is important in facilitating antiviral susceptibility monitoring of NAI resistance in AIVs. IMPORTANCE The frequency of human infections with avian influenza viruses (AIVs) has increased in recent years. Despite the availability of vaccines, neuraminidase inhibitors (NAIs), as the only available class of drugs for AIVs in humans, have been constantly used for treatment, leading to the inevitable emergence

Weighing serological evidence of human exposure to animal influenza viruses − a literature review

PubMed Central

Sikkema, Reina Saapke; Freidl, Gudrun Stephanie; de Bruin, Erwin; Koopmans, Marion

2016-01-01

Assessing influenza A virus strains circulating in animals and their potential to cross the species barrier and cause human infections is important to improve human influenza surveillance and preparedness. We reviewed studies describing serological evidence of human exposure to animal influenza viruses. Comparing serological data is difficult due to a lack of standardisation in study designs and in laboratory methods used in published reports. Therefore, we designed a scoring system to assess and weigh specificity of obtained serology results in the selected articles. Many studies report reliable evidence of antibodies to swine influenza viruses among persons occupationally exposed to pigs. Most avian influenza studies target H5, H7 and H9 subtypes and most serological evidence of human exposure to avian influenza viruses is reported for these subtypes. Avian influenza studies receiving a low grade in this review often reported higher seroprevalences in humans compared with studies with a high grade. Official surveillance systems mainly focus on avian H5 and H7 viruses. Swine influenza viruses and avian subtypes other than H5 and H7 (emphasising H9) should be additionally included in official surveillance systems. Surveillance efforts should also be directed towards understudied geographical areas, such as Africa and South America. PMID:27874827

Serologic evidence of influenza A(H1N1)pdm09 virus in northern sea otters

USGS Publications Warehouse

Li, Zhu-Nan; Ip, Hon S.; Frost, Jessica F.; White, C. LeAnn; Murray, Michael J.; Carney, Paul J.; Sun, Xiang-Jie; Stevens, James; Levine, Min Z.; Katz, Jacqueline M.

2014-01-01

Sporadic epizootics of pneumonia among marine mammals have been associated with multiple animal-origin influenza A virus subtypes (1–6); seals are the only known nonhuman host for influenza B viruses (7). Recently, we reported serologic evidence of influenza A virus infection in free-ranging northern sea otters (Enhydra lutris kenyoni) captured off the coast of Washington, USA, in August 2011 (8). To investigate further which influenza A virus subtype infected these otters, we tested serum samples from these otters by ELISA for antibody-binding activity against 12 recombinant hemagglutinins (rHAs) from 7 influenza A hemagglutinin (HA) subtypes and 2 lineages of influenza B virus (Technical Appendix Table 1). Estimated ages for the otters were 2–19 years (Technical Appendix Table 2); we also tested archived serum samples from sea otters of similar ages collected from a study conducted during 2001–2002 along the Washington coast (9).

New World Bats Harbor Diverse Influenza A Viruses

PubMed Central

Tong, Suxiang; Zhu, Xueyong; Li, Yan; Shi, Mang; Zhang, Jing; Bourgeois, Melissa; Yang, Hua; Chen, Xianfeng; Recuenco, Sergio; Gomez, Jorge; Chen, Li-Mei; Johnson, Adam; Tao, Ying; Dreyfus, Cyrille; Yu, Wenli; McBride, Ryan; Carney, Paul J.; Gilbert, Amy T.; Chang, Jessie; Guo, Zhu; Davis, Charles T.; Paulson, James C.; Stevens, James; Rupprecht, Charles E.; Holmes, Edward C.; Wilson, Ian A.; Donis, Ruben O.

2013-01-01

Aquatic birds harbor diverse influenza A viruses and are a major viral reservoir in nature. The recent discovery of influenza viruses of a new H17N10 subtype in Central American fruit bats suggests that other New World species may similarly carry divergent influenza viruses. Using consensus degenerate RT-PCR, we identified a novel influenza A virus, designated as H18N11, in a flat-faced fruit bat (Artibeus planirostris) from Peru. Serologic studies with the recombinant H18 protein indicated that several Peruvian bat species were infected by this virus. Phylogenetic analyses demonstrate that, in some gene segments, New World bats harbor more influenza virus genetic diversity than all other mammalian and avian species combined, indicative of a long-standing host-virus association. Structural and functional analyses of the hemagglutinin and neuraminidase indicate that sialic acid is not a ligand for virus attachment nor a substrate for release, suggesting a unique mode of influenza A virus attachment and activation of membrane fusion for entry into host cells. Taken together, these findings indicate that bats constitute a potentially important and likely ancient reservoir for a diverse pool of influenza viruses. PMID:24130481

Development of a Reverse Transcription Loop-Mediated Isothermal Amplification Method for the Rapid Detection of Subtype H7N9 Avian Influenza Virus

PubMed Central

Bao, Hongmei; Zhao, Yuhui; Wang, Yunhe; Xu, Xiaolong; Shi, Jianzhong; Zeng, Xianying; Wang, Xiurong; Chen, Hualan

2014-01-01

A novel influenza A (H7N9) virus has emerged in China. To rapidly detect this virus from clinical samples, we developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the detection of the H7N9 virus. The minimum detection limit of the RT-LAMP assay was 0.01 PFU H7N9 virus, making this method 100-fold more sensitive to the detection of the H7N9 virus than conventional RT-PCR. The H7N9 virus RT-LAMP assays can efficiently detect different sources of H7N9 influenza virus RNA (from chickens, pigeons, the environment, and humans). No cross-reactive amplification with the RNA of other subtype influenza viruses or of other avian respiratory viruses was observed. The assays can effectively detect H7N9 influenza virus RNA in drinking water, soil, cloacal swab, and tracheal swab samples that were collected from live poultry markets, as well as human H7N9 virus, in less than 30 min. These results suggest that the H7N9 virus RT-LAMP assays were efficient, practical, and rapid diagnostic methods for the epidemiological surveillance and diagnosis of influenza A (H7N9) virus from different resource samples. PMID:24689044

Bacterial Lipopolysaccharide Destabilizes Influenza Viruses.

PubMed

Bandoro, Christopher; Runstadler, Jonathan A

2017-01-01

Depending on the specific viral pathogen, commensal bacteria can promote or reduce the severity of viral infection and disease progression in their hosts. Influenza A virus (IAV) has a broad host range, comprises many subtypes, and utilizes different routes of transmission, including the fecal-oral route in wild birds. It has been previously demonstrated that commensal bacteria can interact with the host's immune system to protect against IAV pathogenesis. However, it is unclear whether bacteria and their products may be interacting directly with IAV to impact virion stability. Herein we show that gastrointestinal (GI) tract bacterial isolates in an in vitro system significantly reduce the stability of IAV. Moreover, bacterial lipopolysaccharide (LPS), found on the exterior surfaces of bacteria, was sufficient to significantly decrease the stability of both human and avian viral strains in a temperature-dependent manner, including at the relevant temperatures of their respective hosts and the external aquatic habitat. The subtype and host origin of the viruses were shown to affect the extent to which IAV was susceptible to LPS. Furthermore, using a receptor binding assay and transmission electron microscopy, we observed that LPS binds to and alters the morphology of influenza virions, suggesting that direct interaction with the viral surface contributes to the observed antiviral effect of LPS on influenza. IMPORTANCE Influenza A virus (IAV), transmitted primarily via the fecal-oral route in wild birds, encounters high concentrations of bacteria and their products. Understanding the extent to which bacteria affect the infectivity of IAV will lead to a broader understanding of viral ecology in reservoir hosts and may lead to insights for the development of therapeutics in respiratory infection. Herein we show that bacteria and lipopolysaccharide (LPS) interact with and destabilize influenza virions. Moreover, we show that LPS reduces the long-term persistence and

Bacterial Lipopolysaccharide Destabilizes Influenza Viruses

PubMed Central

2017-01-01

ABSTRACT Depending on the specific viral pathogen, commensal bacteria can promote or reduce the severity of viral infection and disease progression in their hosts. Influenza A virus (IAV) has a broad host range, comprises many subtypes, and utilizes different routes of transmission, including the fecal-oral route in wild birds. It has been previously demonstrated that commensal bacteria can interact with the host’s immune system to protect against IAV pathogenesis. However, it is unclear whether bacteria and their products may be interacting directly with IAV to impact virion stability. Herein we show that gastrointestinal (GI) tract bacterial isolates in an in vitro system significantly reduce the stability of IAV. Moreover, bacterial lipopolysaccharide (LPS), found on the exterior surfaces of bacteria, was sufficient to significantly decrease the stability of both human and avian viral strains in a temperature-dependent manner, including at the relevant temperatures of their respective hosts and the external aquatic habitat. The subtype and host origin of the viruses were shown to affect the extent to which IAV was susceptible to LPS. Furthermore, using a receptor binding assay and transmission electron microscopy, we observed that LPS binds to and alters the morphology of influenza virions, suggesting that direct interaction with the viral surface contributes to the observed antiviral effect of LPS on influenza. IMPORTANCE Influenza A virus (IAV), transmitted primarily via the fecal-oral route in wild birds, encounters high concentrations of bacteria and their products. Understanding the extent to which bacteria affect the infectivity of IAV will lead to a broader understanding of viral ecology in reservoir hosts and may lead to insights for the development of therapeutics in respiratory infection. Herein we show that bacteria and lipopolysaccharide (LPS) interact with and destabilize influenza virions. Moreover, we show that LPS reduces the long

Serological and molecular prevalence of swine influenza virus on farms in northwestern Mexico.

PubMed

López-Robles, Guadalupe; Montalvo-Corral, Maricela; Burgara-Estrella, Alexel; Hernández, Jesús

2014-08-06

The aim of this study was to provide an overview of the epidemiological status of swine influenza viruses in pigs from northwestern Mexico in 2008-2009. A serological and molecular survey was conducted in 150 pigs from 15 commercial farms in Sonora, Mexico (northwestern region of Mexico). The serological data showed that 55% of the sera were positive for the H1N1 subtype, 59% for the H3N2 subtype, and 38% for both subtypes. Overall, 16.6% (25/150) of the samples were positive for type A influenza by qRT-PCR. The phylogenetic analysis of the H1 viruses circulating in northwestern Mexico were grouped into cluster α, from five other clusters previously described. The influenza virus H1 circulating in northwestern Mexico showed 97-100% identity at the nucleotide level among them, 89% identity with other North American strains, 88% with strains from central Mexico, and 85% with the pandemic A/H1N1p2009 virus. Meanwhile, a closer relationship with some influenza viruses from North America (97% nucleotide identity) was found for H3 subtype. In conclusion, our results demonstrated a high circulation of strains similar to those observed in the North American linage among commercial farms in northwestern Mexico, involving of a different lineage virus different to the influenza pandemic of 2009. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecular subtyping of European swine influenza viruses and scaling to high-throughput analysis.

PubMed

Bonin, Emilie; Quéguiner, Stéphane; Woudstra, Cédric; Gorin, Stéphane; Barbier, Nicolas; Harder, Timm C; Fach, Patrick; Hervé, Séverine; Simon, Gaëlle

2018-01-10

Swine influenza is a respiratory infection of pigs that may have a significant economic impact in affected herds and pose a threat to the human population since swine influenza A viruses (swIAVs) are zoonotic pathogens. Due to the increasing genetic diversity of swIAVs and because novel reassortants or variants may become enzootic or have zoonotic implications, surveillance is strongly encouraged. Therefore, diagnostic tests and advanced technologies able to identify the circulating strains rapidly are critically important. Several reverse transcription real-time PCR assays (RT-qPCRs) were developed to subtype European swIAVs in clinical samples previously identified as containing IAV genome. The RT-qPCRs aimed to discriminate HA genes of four H1 genetic lineages (H1 av , H1 hu , H1 huΔ146-147 , H1pdm) and one H3 lineage, and NA genes of two N1 lineages (N1, N1pdm) and one N2 lineage. After individual validation, each RT-qPCR was adapted to high-throughput analyses in parallel to the amplification of the IAV M gene (target for IAV detection) and the β-actin gene (as an internal control), in order to test the ten target genes simultaneously on a large number of clinical samples, using low volumes of reagents and RNA extracts. The RT-qPCRs dedicated to IAV molecular subtyping enabled the identification of swIAVs from the four viral subtypes that are known to be enzootic in European pigs, i.e. H1 av N1, H1 hu N2, H3N2 and H1N1pdm. They also made it possible to discriminate a new antigenic variant (H1 hu N2 Δ146-147 ) among H1 hu N2 viruses, as well as reassortant viruses, such as H1 hu N1 or H1 av N2 for example, and virus mixtures. These PCR techniques exhibited a gain in sensitivity as compared to end-point RT-PCRs, enabling the characterization of biological samples with low genetic loads, with considerable time saving. Adaptation to high-throughput analyses appeared effective, both in terms of specificity and sensitivity. This new development opens novel

Antigenic and Molecular Characterization of Avian Influenza A(H9N2) Viruses, Bangladesh

PubMed Central

Shanmuganatham, Karthik; Feeroz, Mohammed M.; Jones-Engel, Lisa; Smith, Gavin J.D.; Fourment, Mathieu; Walker, David; McClenaghan, Laura; Alam, S.M. Rabiul; Hasan, M. Kamrul; Seiler, Patrick; Franks, John; Danner, Angie; Barman, Subrata; McKenzie, Pamela; Krauss, Scott; Webby, Richard J.

2013-01-01

Human infection with avian influenza A(H9N2) virus was identified in Bangladesh in 2011. Surveillance for influenza viruses in apparently healthy poultry in live-bird markets in Bangladesh during 2008–2011 showed that subtype H9N2 viruses are isolated year-round, whereas highly pathogenic subtype H5N1 viruses are co-isolated with subtype H9N2 primarily during the winter months. Phylogenetic analysis of the subtype H9N2 viruses showed that they are reassortants possessing 3 gene segments related to subtype H7N3; the remaining gene segments were from the subtype H9N2 G1 clade. We detected no reassortment with subtype H5N1 viruses. Serologic analyses of subtype H9N2 viruses from chickens revealed antigenic conservation, whereas analyses of viruses from quail showed antigenic drift. Molecular analysis showed that multiple mammalian-specific mutations have become fixed in the subtype H9N2 viruses, including changes in the hemagglutinin, matrix, and polymerase proteins. Our results indicate that these viruses could mutate to be transmissible from birds to mammals, including humans. PMID:23968540

Analysis of influenza A viruses of subtype H1 from wild birds, turkeys and pigs in Germany reveals interspecies transmission events.

PubMed

Starick, Elke; Fereidouni, Sasan R; Lange, Elke; Grund, Christian; Vahlenkamp, Thomas; Beer, Martin; Harder, Timm C

2011-07-01

Despite considerable host species barriers, interspecies transmissions of influenza A viruses between wild birds, poultry and pigs have been demonstrated repeatedly. In particular, viruses of the subtypes H1 and H3 were transmitted between pigs and poultry, predominantly turkeys, in regions with a high population density of both species. The recovery of a swine influenza H1N1 virus from a turkey flock in Germany in 2009 prompted us to investigate molecularly the subtype H1 viruses recently detected in wild birds, pigs and poultry. The goal of this study was to investigate the relationship between H1N1 viruses originating from wild and domestic animals of Germany and to identify potential trans-species transmission or reassortment events. Hemagglutinin and neuraminidase gene or full-length genome sequences were generated from selected, current H1N1 viruses from wild birds, pigs and turkeys. Phylogenetic analyses were combined with genotyping and analyses of the deduced amino acid sequences with respect to biologically active sites. Antigenic relationships were assessed by hemagglutination inhibition reactions. Phylogenetic analysis of the hemagglutinin sequences showed that viruses from distinct H1 subgroups co-circulate among domestic animals and wild birds. In addition, these viruses comprised different genotypes and were distinguishable antigenically. An H1N1 virus isolated from a turkey farm in northern Germany in 2009 showed the highest similarity with the avian-like porcine H1N1 influenza viruses circulating in Europe since the late 1970s. The data demonstrate the genetic and antigenic heterogeneity of H1 viruses currently circulating in domestic and wild animals in Germany and points to turkeys as a possible bridge between avian and mammalian hosts. © 2011 Blackwell Publishing Ltd.

Discordant detection of avian influenza virus subtypes in time and space between poultry and wild birds; Towards improvement of surveillance programs

PubMed Central

Verhagen, Josanne H.; Lexmond, Pascal; Vuong, Oanh; Schutten, Martin; Guldemeester, Judith; Osterhaus, Albert D. M. E.; Elbers, Armin R. W.; Slaterus, Roy; Hornman, Menno; Koch, Guus; Fouchier, Ron A. M.

2017-01-01

Avian influenza viruses from wild birds can cause outbreaks in poultry, and occasionally infect humans upon exposure to infected poultry. Identification and characterization of viral reservoirs and transmission routes is important to develop strategies that prevent infection of poultry, and subsequently virus transmission between poultry holdings and to humans. Based on spatial, temporal and phylogenetic analyses of data generated as part of intense and large-scale influenza surveillance programs in wild birds and poultry in the Netherlands from 2006 to 2011, we demonstrate that LPAIV subtype distribution differed between wild birds and poultry, suggestive of host-range restrictions. LPAIV isolated from Dutch poultry were genetically most closely related to LPAIV isolated from wild birds in the Netherlands or occasionally elsewhere in Western Europe. However, a relatively long time interval was observed between the isolations of related viruses from wild birds and poultry. Spatial analyses provided evidence for mallards (Anas platyrhynchos) being more abundant near primary infected poultry farms. Detailed year-round investigation of virus prevalence and wild bird species distribution and behavior near poultry farms should be used to improve risk assessment in relation to avian influenza virus introduction and retarget avian influenza surveillance programs. PMID:28278281

Discordant detection of avian influenza virus subtypes in time and space between poultry and wild birds; Towards improvement of surveillance programs.

PubMed

Verhagen, Josanne H; Lexmond, Pascal; Vuong, Oanh; Schutten, Martin; Guldemeester, Judith; Osterhaus, Albert D M E; Elbers, Armin R W; Slaterus, Roy; Hornman, Menno; Koch, Guus; Fouchier, Ron A M

2017-01-01

Avian influenza viruses from wild birds can cause outbreaks in poultry, and occasionally infect humans upon exposure to infected poultry. Identification and characterization of viral reservoirs and transmission routes is important to develop strategies that prevent infection of poultry, and subsequently virus transmission between poultry holdings and to humans. Based on spatial, temporal and phylogenetic analyses of data generated as part of intense and large-scale influenza surveillance programs in wild birds and poultry in the Netherlands from 2006 to 2011, we demonstrate that LPAIV subtype distribution differed between wild birds and poultry, suggestive of host-range restrictions. LPAIV isolated from Dutch poultry were genetically most closely related to LPAIV isolated from wild birds in the Netherlands or occasionally elsewhere in Western Europe. However, a relatively long time interval was observed between the isolations of related viruses from wild birds and poultry. Spatial analyses provided evidence for mallards (Anas platyrhynchos) being more abundant near primary infected poultry farms. Detailed year-round investigation of virus prevalence and wild bird species distribution and behavior near poultry farms should be used to improve risk assessment in relation to avian influenza virus introduction and retarget avian influenza surveillance programs.

Development of a reverse transcription loop-mediated isothermal amplification method for the rapid detection of avian influenza virus subtype H7.

PubMed

Bao, Hongmei; Wang, Xiurong; Zhao, Yuhui; Sun, Xiaodong; Li, Yanbing; Xiong, Yongzhong; Chen, Hualan

2012-01-01

A rapid and sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the detection of the H7 avian influenza virus (H7 AIV) isotype was developed. The minimum detection limit of the RT-LAMP assay was 0.1-0.01 PFU per reaction for H7 AIV RNA, making this assay 100-fold more sensitive than the conventional RT-PCR method. This RT-LAMP assay also has the capacity to detect both high- and low-pathogenic H7 AIV strains. Using a pool of RNAs extracted from influenza viruses corresponding to all 15 HA subtypes (in addition to other avian pathogenic viruses), the RT-LAMP system was confirmed to amplify only H7 AIV RNA. Furthermore, specific pathogen free (SPF) chickens were infected artificially with H7 AIV, throat and cloacal swabs were collected, and viral shedding was examined using viral isolation, RT-PCR and RT-LAMP. Shedding was detected following viral isolation and RT-LAMP one day after infection, whereas viral detection using RT-PCR was effective only on day 3 post-infection. These results indicate that the RT-LAMP method could facilitate epidemiological surveillance and the rapid diagnosis of the avian influenza subtype H7. Copyright © 2011 Elsevier B.V. All rights reserved.

Long-term variation in influenza A virus prevalence and subtype diversity in migratory mallards in northern Europe

PubMed Central

Latorre-Margalef, Neus; Tolf, Conny; Grosbois, Vladimir; Avril, Alexis; Bengtsson, Daniel; Wille, Michelle; Osterhaus, Albert D. M. E.; Fouchier, Ron A. M.; Olsen, Björn; Waldenström, Jonas

2014-01-01

Data on long-term circulation of pathogens in wildlife populations are seldom collected, and hence understanding of spatial–temporal variation in prevalence and genotypes is limited. Here, we analysed a long-term surveillance series on influenza A virus (IAV) in mallards collected at an important migratory stopover site from 2002 to 2010, and characterized seasonal dynamics in virus prevalence and subtype diversity. Prevalence dynamics were influenced by year, but retained a common pattern for all years whereby prevalence was low in spring and summer, but increased in early autumn with a first peak in August, and a second more pronounced peak during October–November. A total of 74 haemagglutinin (HA)/neuraminidase (NA) combinations were isolated, including all NA and most HA (H1–H12) subtypes. The most common subtype combinations were H4N6, H1N1, H2N3, H5N2, H6N2 and H11N9, and showed a clear linkage between specific HA and NA subtypes. Furthermore, there was a temporal structuring of subtypes within seasons based on HA phylogenetic relatedness. Dissimilar HA subtypes tended to have different temporal occurrence within seasons, where the subtypes that dominated in early autumn were rare in late autumn, and vice versa. This suggests that build-up of herd immunity affected IAV dynamics in this system. PMID:24573857

Studying the pathogenicity of avian influenza viruses in different avian species

USDA-ARS?s Scientific Manuscript database

Avian influenza (AI) viruses are significant pathogens of domestic poultry worldwide. Wild aquatic birds are the primordial reservoirs of AI viruses, which are classified as low pathogenic (LP) and can be any of the 16 hemagglutinin subtypes (H1-16). Circulation of H5 or H7 subtype LPAI viruses in...

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

PubMed

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

2013-05-01

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

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

PubMed Central

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

2012-01-01

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

Sialic acid content in human saliva and anti-influenza activity against human and avian influenza viruses.

PubMed

Limsuwat, Nattavatchara; Suptawiwat, Ornpreya; Boonarkart, Chompunuch; Puthavathana, Pilaipan; Wiriyarat, Witthawat; Auewarakul, Prasert

2016-03-01

It was shown previously that human saliva has higher antiviral activity against human influenza viruses than against H5N1 highly pathogenic avian influenza viruses, and that the major anti-influenza activity was associated with sialic-acid-containing molecules. To further characterize the differential susceptibility to saliva among influenza viruses, seasonal influenza A and B virus, pandemic H1N1 virus, and 15 subtypes of avian influenza virus were tested for their susceptibility to human and chicken saliva. Human saliva showed higher hemagglutination inhibition (HI) and neutralization (NT) titers against seasonal influenza A virus and the pandemic H1N1 viruses than against influenza B virus and most avian influenza viruses, except for H9N2 and H12N9 avian influenza viruses, which showed high HI and NT titers. To understand the nature of sialic-acid-containing anti-influenza factors in human saliva, α2,3- and α2,6-linked sialic acid was measured in human saliva samples using a lectin binding and dot blot assay. α2,6-linked sialic acid was found to be more abundant than α2,3-linked sialic acid, and a seasonal H1N1 influenza virus bound more efficiently to human saliva than an H5N1 virus in a dot blot analysis. These data indicated that human saliva contains the sialic acid type corresponding to the binding preference of seasonal influenza viruses.

Comparison of Shedding Characteristics of Seasonal Influenza Virus (Sub)Types and Influenza A(H1N1)pdm09; Germany, 2007–2011

PubMed Central

Suess, Thorsten; Remschmidt, Cornelius; Schink, Susanne B.; Schweiger, Brunhilde; Heider, Alla; Milde, Jeanette; Nitsche, Andreas; Schroeder, Kati; Doellinger, Joerg; Braun, Christian; Haas, Walter; Krause, Gérard; Buchholz, Udo

2012-01-01

Background Influenza viral shedding studies provide fundamental information for preventive strategies and modelling exercises. We conducted a prospective household study to investigate viral shedding in seasonal and pandemic influenza between 2007 and 2011 in Berlin and Munich, Germany. Methods Study physicians recruited index patients and their household members. Serial nasal specimens were obtained from all household members over at least eight days and tested quantitatively by qRT-PCR for the influenza virus (sub)type of the index patient. A subset of samples was also tested by viral culture. Symptoms were recorded daily. Results We recruited 122 index patients and 320 household contacts, of which 67 became secondary household cases. Among all 189 influenza cases, 12 were infected with seasonal/prepandemic influenza A(H1N1), 19 with A(H3N2), 60 with influenza B, and 98 with A(H1N1)pdm09. Nine (14%) of 65 non-vaccinated secondary cases were asymptomatic/subclinical (0 (0%) of 21 children, 9 (21%) of 44 adults; p = 0.03). Viral load among patients with influenza-like illness (ILI) peaked on illness days 1, 2 or 3 for all (sub)types and declined steadily until days 7–9. Clinical symptom scores roughly paralleled viral shedding dynamics. On the first day prior to symptom onset 30% (12/40) of specimens were positive. Viral load in 6 asymptomatic/subclinical patients was similar to that in ILI-patients. Duration of infectiousness as measured by viral culture lasted approximately until illness days 4–6. Viral load did not seem to be influenced by antiviral therapy, age or vaccination status. Conclusion Asymptomatic/subclinical infections occur infrequently, but may be associated with substantial amounts of viral shedding. Presymptomatic shedding may arise in one third of cases, and shedding characteristics appear to be independent of (seasonal or pandemic) (sub)type, age, antiviral therapy or vaccination; however the power to find moderate differences was

Protection of chickens to antigenically variant avian influenza virus challenge after immunization with two antigenically unrelated strains of the same subtype

USDA-ARS?s Scientific Manuscript database

The antigenic diversity of avian influenza virus (AIV) within a subtype has been well established and is believed to be driven by the selection of immunologic escape mutants. In regions where vaccination against AIV has been implemented for prolonged periods (e.g. Vietnam and Egypt), vaccines which...

TMPRSS2 Independency for Haemagglutinin Cleavage In Vivo Differentiates Influenza B Virus from Influenza A Virus

PubMed Central

Sakai, Kouji; Ami, Yasushi; Nakajima, Noriko; Nakajima, Katsuhiro; Kitazawa, Minori; Anraku, Masaki; Takayama, Ikuyo; Sangsriratanakul, Natthanan; Komura, Miyuki; Sato, Yuko; Asanuma, Hideki; Takashita, Emi; Komase, Katsuhiro; Takehara, Kazuaki; Tashiro, Masato; Hasegawa, Hideki; Odagiri, Takato; Takeda, Makoto

2016-01-01

Influenza A and B viruses show clear differences in their host specificity and pandemic potential. Recent studies have revealed that the host protease TMPRSS2 plays an essential role for proteolytic activation of H1, H3, and H7 subtype strains of influenza A virus (IAV) in vivo. IAV possessing a monobasic cleavage site in the haemagglutinin (HA) protein replicates poorly in TMPRSS2 knockout mice owing to insufficient HA cleavage. In the present study, human isolates of influenza B virus (IBV) strains and a mouse-adapted IBV strain were analysed. The data showed that IBV successfully underwent HA cleavage in TMPRSS2 knockout mice, and that the mouse-adapted strain was fully pathogenic to these mice. The present data demonstrate a clear difference between IAV and IBV in their molecular mechanisms for spreading in vivo. PMID:27389476

TMPRSS2 Independency for Haemagglutinin Cleavage In Vivo Differentiates Influenza B Virus from Influenza A Virus.

PubMed

Sakai, Kouji; Ami, Yasushi; Nakajima, Noriko; Nakajima, Katsuhiro; Kitazawa, Minori; Anraku, Masaki; Takayama, Ikuyo; Sangsriratanakul, Natthanan; Komura, Miyuki; Sato, Yuko; Asanuma, Hideki; Takashita, Emi; Komase, Katsuhiro; Takehara, Kazuaki; Tashiro, Masato; Hasegawa, Hideki; Odagiri, Takato; Takeda, Makoto

2016-07-08

Influenza A and B viruses show clear differences in their host specificity and pandemic potential. Recent studies have revealed that the host protease TMPRSS2 plays an essential role for proteolytic activation of H1, H3, and H7 subtype strains of influenza A virus (IAV) in vivo. IAV possessing a monobasic cleavage site in the haemagglutinin (HA) protein replicates poorly in TMPRSS2 knockout mice owing to insufficient HA cleavage. In the present study, human isolates of influenza B virus (IBV) strains and a mouse-adapted IBV strain were analysed. The data showed that IBV successfully underwent HA cleavage in TMPRSS2 knockout mice, and that the mouse-adapted strain was fully pathogenic to these mice. The present data demonstrate a clear difference between IAV and IBV in their molecular mechanisms for spreading in vivo.

Risk perceptions for avian influenza virus infection among poultry workers, China.

PubMed

Yu, Qi; Liu, Linqing; Pu, Juan; Zhao, Jingyi; Sun, Yipeng; Shen, Guangnian; Wei, Haitao; Zhu, Junjie; Zheng, Ruifeng; Xiong, Dongyan; Liu, Xiaodong; Liu, Jinhua

2013-02-01

To determine risk for avian influenza virus infection, we conducted serologic surveillance for H5 and H9 subtypes among poultry workers in Beijing, China, 2009-2010, and assessed workers' understanding of avian influenza. We found that poultry workers had considerable risk for infection with H9 subtypes. Increasing their knowledge could prevent future infections.

New vaccines against influenza virus

PubMed Central

Lee, Young-Tae; Kim, Ki-Hye; Ko, Eun-Ju; Lee, Yu-Na; Kim, Min-Chul; Kwon, Young-Man; Tang, Yinghua; Cho, Min-Kyoung; Lee, Youn-Jeong

2014-01-01

Vaccination is one of the most effective and cost-benefit interventions that prevent the mortality and reduce morbidity from infectious pathogens. However, the licensed influenza vaccine induces strain-specific immunity and must be updated annually based on predicted strains that will circulate in the upcoming season. Influenza virus still causes significant health problems worldwide due to the low vaccine efficacy from unexpected outbreaks of next epidemic strains or the emergence of pandemic viruses. Current influenza vaccines are based on immunity to the hemagglutinin antigen that is highly variable among different influenza viruses circulating in humans and animals. Several scientific advances have been endeavored to develop universal vaccines that will induce broad protection. Universal vaccines have been focused on regions of viral proteins that are highly conserved across different virus subtypes. The strategies of universal vaccines include the matrix 2 protein, the hemagglutinin HA2 stalk domain, and T cell-based multivalent antigens. Supplemented and/or adjuvanted vaccination in combination with universal target antigenic vaccines would have much promise. This review summarizes encouraging scientific advances in the field with a focus on novel vaccine designs. PMID:24427759

Antibodies induced by the HA2 glycopolypeptide of influenza virus haemagglutinin improve recovery from influenza A virus infection.

PubMed

Gocník, M; Fislová, T; Mucha, V; Sládková, T; Russ, G; Kostolansky, F; Varecková, E

2008-04-01

The haemagglutinin (HA) of influenza A virus consists of two glycopolypeptides designated HA1 and HA2. Antibodies recognizing HA1 inhibit virus haemagglutination, neutralize virus infectivity and provide good protection against infection, but do not cross-react with the HA of other subtypes. Little is known regarding the biological activities of antibodies against HA2. To study the role of antibodies directed against HA2 during influenza virus infection, two vaccinia virus recombinants (rVVs) were used expressing chimeric molecules of HA, in which HA1 and HA2 were derived from different HA subtypes. The KG-11 recombinant expressed HA1 from A/PR/8/34 (H1N1) virus and HA2 from A/NT/60 (H3N2) virus, whilst KG-12 recombinant expressed HA1 from A/NT/60 virus and HA2 from A/PR/8/34 virus. Immunization of BALB/c mice with rVV expressing HA2 of the HA subtype homologous to the challenge virus [A/PR/8/34 (H1N1) or A/Mississippi/1/85 (H3N2)] did not prevent virus infection, but nevertheless resulted in an increase in mice survival and faster elimination of virus from the lungs. Passive immunization with antibodies purified from mice immunized with rVVs confirmed that antibodies against HA2 were responsible for the described effect on virus infection. Based on the facts that HA2 is a rather conserved part of the HA and that antibodies against HA2, as shown here, may moderate virus infection, future vaccine design should deal with the problem of how to increase the HA2 antibody response.

Influenza virus isolations at the Government of India Influenza Centre, Coonoor, during 1950-60.

PubMed

VEERARAGHAVAN, N

1961-01-01

In 1950, responding to an invitation by the World Health Organization to all its Member States to establish regional laboratories for the study, in collaboration with the World Influenza Centre, of the distribution and antigenic pattern of influenza viruses, the Government of India set up an Influenza Centre at the Pasteur Institute of Southern India, Coonoor. The author presents a study of the antigenic pattern and variation of the influenza virus strains isolated at the Government of India Influenza Centre during 1950-60. Of the 152 strains isolated, 135 were type A viruses (23 belonging to the A1/Liverpool/50 subtype, 5 to A1/Eire/55, 10 to A1/Ned/56 and 97 to A2/Asia/57), 15 were type B viruses, and 2 were type C viruses. Two striking facts that emerged from this study were the absence of the Scandinavian strains from the area in which the viruses were isolated and the total disappearance of old strains after a new one had appeared.

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

PubMed Central

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

2013-01-01

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

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

PubMed

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

2015-05-01

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

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

PubMed Central

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

2015-01-01

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

Isolation and genetic characterization of avian influenza viruses and a Newcastle disease virus from wild birds in Barbados: 2003-2004.

PubMed

Douglas, Kirk O; Lavoie, Marc C; Kim, L Mia; Afonso, Claudio L; Suarez, David L

2007-09-01

Zoonotic transmission of an H5N1 avian influenza A virus to humans in 2003-present has generated increased public health and scientific interest in the prevalence and variability of influenza A viruses in wild birds and their potential threat to human health. Migratory waterfowl and shorebirds are regarded as the primordial reservoir of all influenza A viral subtypes and have been repeatedly implicated in avian influenza outbreaks in domestic poultry and swine. All of the 16 hemagglutinin and nine neuraminidase influenza subtypes have been isolated from wild birds, but waterfowl of the order Anseriformes are the most commonly infected. Using 9-to-11-day-old embryonating chicken egg culture, virus isolation attempts were conducted on 168 cloacal swabs from various resident, imported, and migratory bird species in Barbados during the months of July to October of 2003 and 2004. Hemagglutination assay and reverse transcription-polymerase chain reaction were used to screen all allantoic fluids for the presence of hemagglutinating agents and influenza A virus. Hemagglutination positive-influenza negative samples were also tested for Newcastle disease virus (NDV), which is also found in waterfowl. Two influenza A viruses and one NDV were isolated from Anseriformes (40/168), with isolation rates of 5.0% (2/40) and 2.5% (1/40), respectively, for influenza A and NDV. Sequence analysis of the influenza A virus isolates showed them to be H4N3 viruses that clustered with other North American avian influenza viruses. This is the first report of the presence of influenza A virus and NDV in wild birds in the English-speaking Caribbean.

Multiplex Reverse Transcription-PCR for Simultaneous Surveillance of Influenza A and B Viruses

PubMed Central

Zhou, Bin; Barnes, John R.; Sessions, October M.; Chou, Tsui-Wen; Wilson, Malania; Stark, Thomas J.; Volk, Michelle; Spirason, Natalie; Halpin, Rebecca A.; Kamaraj, Uma Sangumathi; Ding, Tao; Stockwell, Timothy B.; Ghedin, Elodie; Barr, Ian G.

2017-01-01

ABSTRACT Influenza A and B viruses are the causative agents of annual influenza epidemics that can be severe, and influenza A viruses intermittently cause pandemics. Sequence information from influenza virus genomes is instrumental in determining mechanisms underpinning antigenic evolution and antiviral resistance. However, due to sequence diversity and the dynamics of influenza virus evolution, rapid and high-throughput sequencing of influenza viruses remains a challenge. We developed a single-reaction influenza A/B virus (FluA/B) multiplex reverse transcription-PCR (RT-PCR) method that amplifies the most critical genomic segments (hemagglutinin [HA], neuraminidase [NA], and matrix [M]) of seasonal influenza A and B viruses for next-generation sequencing, regardless of viral type, subtype, or lineage. Herein, we demonstrate that the strategy is highly sensitive and robust. The strategy was validated on thousands of seasonal influenza A and B virus-positive specimens using multiple next-generation sequencing platforms. PMID:28978683

Multiyear Surveillance for Avian Influenza Virus in Waterfowl from Wintering Grounds, Texas Coast, USA

PubMed Central

Ferro, Pamela J.; Budke, Christine M.; Peterson, Markus J.; Cox, Dayna; Roltsch, Emily; Merendino, Todd; Nelson, Matt

2010-01-01

We studied the prevalence of influenza A virus in wintering waterfowl from the Central Flyway on the Gulf Coast of Texas. Of 5,363 hunter-harvested migratory and resident waterfowl and wetland-associated game birds sampled during 3 consecutive hunting seasons (September–January 2006–07, 2007–08, and 2008–09), real-time reverse transcription–PCR detected influenza A matrix sequences in 8.5% of samples, H5 in 0.7%, and H7 in 0.6%. Virus isolation yielded 134 influenza A viruses, including N1–N9, H1–H7, H10, and H11 subtypes. Low-pathogenicity H7 subtype was isolated during January, September, and November 2007 and January 2008; low-pathogenicity H5 subtype was isolated during November and December 2007. PMID:20678315

Prevalence of influenza virus among the paediatric population in Mumbai during 2007-2009.

PubMed

Roy, S; Patil, D; Dahake, R; Mukherjee, S; Athlekar, S V; Deshmukh, R A; Chowdhary, A

2012-01-01

Influenza has a major impact on public heath, annually affecting 15-20% of the global population. Information on the activity of influenza virus in Mumbai is limited. The present study was carried out to determine the prevalence of influenza viruses causing acute respiratory infections in children by molecular methods. To study the prevalence of influenza viruses among the paediatric population in Mumbai by real-time reverse-transcriptase polymerase chain reaction (rRT-PCR). From July 2007 to July 2009, 100 respiratory samples (nasal and throat swabs) were collected from paediatric patients with acute respiratory symptoms. attending out patients department, and admitted to the paediatric wards of B. J. Wadia Hospital for Children, Mumbai. The samples were collected and processed as per World Health Organization (WHO) guidelines. Viral RNA was extracted and one-step rRT-PCR was performed to detect influenza type A (H1 and H3) and influenza type B virus. Out of 100 samples processed by rRT-PCR, a total of 11 samples (11%) were positive for influenza virus. The typing for influenza A subtypes showed 1% (1) positivity for H1 and 5% (5) positivity for H3 subtypes and 5% (5) samples tested positive for influenza type B virus. It was observed that both influenza type A and B viruses were prevalent in Mumbai during the study period. Such surveillance data are important in the early detection of any antigenic variants that may be helpful in global influenza vaccine preparation and for any pandemic preparedness activity.

Competition between influenza A virus subtypes through heterosubtypic immunity modulates re-infection and antibody dynamics in the mallard duck.

PubMed

Latorre-Margalef, Neus; Brown, Justin D; Fojtik, Alinde; Poulson, Rebecca L; Carter, Deborah; Franca, Monique; Stallknecht, David E

2017-06-01

Our overall hypothesis is that host population immunity directed at multiple antigens will influence the prevalence, diversity and evolution of influenza A virus (IAV) in avian populations where the vast subtype diversity is maintained. To investigate how initial infection influences the outcome of later infections with homologous or heterologous IAV subtypes and how viruses interact through host immune responses, we carried out experimental infections in mallard ducks (Anas platyrhynchos). Mallards were pre-challenged with an H3N8 low-pathogenic IAV and were divided into six groups. At five weeks post H3N8 inoculation, each group was challenged with a different IAV subtype (H4N5, H10N7, H6N2, H12N5) or the same H3N8. Two additional pre-challenged groups were inoculated with the homologous H3N8 virus at weeks 11 and 15 after pre-challenge to evaluate the duration of protection. The results showed that mallards were still resistant to re-infection after 15 weeks. There was a significant reduction in shedding for all pre-challenged groups compared to controls and the outcome of the heterologous challenges varied according to hemagglutinin (HA) phylogenetic relatedness between the viruses used. There was a boost in the H3 antibody titer after re-infection with H4N5, which is consistent with original antigenic sin or antigenic seniority and suggest a putative strategy of virus evasion. These results imply competition between related subtypes that could regulate IAV subtype population dynamics in nature. Collectively, we provide new insights into within-host IAV complex interactions as drivers of IAV antigenic diversity that could allow the circulation of multiple subtypes in wild ducks.

Competition between influenza A virus subtypes through heterosubtypic immunity modulates re-infection and antibody dynamics in the mallard duck

PubMed Central

Brown, Justin D.; Carter, Deborah; Franca, Monique; Stallknecht, David E.

2017-01-01

Our overall hypothesis is that host population immunity directed at multiple antigens will influence the prevalence, diversity and evolution of influenza A virus (IAV) in avian populations where the vast subtype diversity is maintained. To investigate how initial infection influences the outcome of later infections with homologous or heterologous IAV subtypes and how viruses interact through host immune responses, we carried out experimental infections in mallard ducks (Anas platyrhynchos). Mallards were pre-challenged with an H3N8 low-pathogenic IAV and were divided into six groups. At five weeks post H3N8 inoculation, each group was challenged with a different IAV subtype (H4N5, H10N7, H6N2, H12N5) or the same H3N8. Two additional pre-challenged groups were inoculated with the homologous H3N8 virus at weeks 11 and 15 after pre-challenge to evaluate the duration of protection. The results showed that mallards were still resistant to re-infection after 15 weeks. There was a significant reduction in shedding for all pre-challenged groups compared to controls and the outcome of the heterologous challenges varied according to hemagglutinin (HA) phylogenetic relatedness between the viruses used. There was a boost in the H3 antibody titer after re-infection with H4N5, which is consistent with original antigenic sin or antigenic seniority and suggest a putative strategy of virus evasion. These results imply competition between related subtypes that could regulate IAV subtype population dynamics in nature. Collectively, we provide new insights into within-host IAV complex interactions as drivers of IAV antigenic diversity that could allow the circulation of multiple subtypes in wild ducks. PMID:28640898

Heterovariant Cross-Reactive B-Cell Responses Induced by the 2009 Pandemic Influenza Virus A Subtype H1N1 Vaccine

PubMed Central

He, Xiao-Song; Sasaki, Sanae; Baer, Jane; Khurana, Surender; Golding, Hana; Treanor, John J.; Topham, David J.; Sangster, Mark Y.; Jin, Hong; Dekker, Cornelia L.; Subbarao, Kanta; Greenberg, Harry B.

2013-01-01

Background. The generation of heterovariant immunity is a highly desirable feature of influenza vaccines. The goal of this study was to compare the heterovariant B-cell response induced by the monovalent inactivated 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) vaccine with that induced by the 2009 seasonal trivalent influenza vaccine (sTIV) containing a seasonal influenza A virus subtype H1N1 (A[H1N1]) component in young and elderly adults. Methods. Plasmablast-derived polyclonal antibodies (PPAb) from young and elderly recipients of A(H1N1)pdm09 vaccine or sTIV were tested for binding activity to various influenza antigens. Results. In A(H1N1)pdm09 recipients, the PPAb titers against homotypic A(H1N1)pdm09 vaccine were similar to those against the heterovariant seasonal A(H1N1) vaccine and were similar between young and elderly subjects. The PPAb avidity was higher among elderly individuals, compared with young individuals. In contrast, the young sTIV recipients had 10-fold lower heterovariant PPAb titers against the A(H1N1)pdm09 vaccine than against the homotypic seasonal A(H1N1) vaccine. In binding assays with recombinant head and stalk domains of hemagglutinin, PPAb from the A(H1N1)pdm09 recipients but not PPAb from the sTIV recipients bound to the conserved stalk domain. Conclusion. The A(H1N1)pdm09 vaccine induced production of PPAb with heterovariant reactivity, including antibodies targeting the conserved hemagglutinin stalk domain. PMID:23107783

Dynamics of influenza A virus infections in permanently infected pig farms: evidence of recurrent infections, circulation of several swine influenza viruses and reassortment events.

PubMed

Rose, Nicolas; Hervé, Séverine; Eveno, Eric; Barbier, Nicolas; Eono, Florent; Dorenlor, Virginie; Andraud, Mathieu; Camsusou, Claire; Madec, François; Simon, Gaëlle

2013-09-04

Concomitant infections by different influenza A virus subtypes within pig farms increase the risk of new reassortant virus emergence. The aims of this study were to characterize the epidemiology of recurrent swine influenza virus infections and identify their main determinants. A follow-up study was carried out in 3 selected farms known to be affected by repeated influenza infections. Three batches of pigs were followed within each farm from birth to slaughter through a representative sample of 40 piglets per batch. Piglets were monitored individually on a monthly basis for serology and clinical parameters. When a flu outbreak occurred, daily virological and clinical investigations were carried out for two weeks. Influenza outbreaks, confirmed by influenza A virus detection, were reported at least once in each batch. These outbreaks occurred at a constant age within farms and were correlated with an increased frequency of sneezing and coughing fits. H1N1 and H1N2 viruses from European enzootic subtypes and reassortants between viruses from these lineages were consecutively and sometimes simultaneously identified depending on the batch, suggesting virus co-circulations at the farm, batch and sometimes individual levels. The estimated reproduction ratio R of influenza outbreaks ranged between 2.5 [1.9-2.9] and 6.9 [4.1-10.5] according to the age at infection-time and serological status of infected piglets. Duration of shedding was influenced by the age at infection time, the serological status of the dam and mingling practices. An impaired humoral response was identified in piglets infected at a time when they still presented maternally-derived antibodies.

Development of Clade-Specific and Broadly Reactive Live Attenuated Influenza Virus Vaccines against Rapidly Evolving H5 Subtype Viruses

PubMed Central

Boonnak, Kobporn; Matsuoka, Yumiko; Wang, Weijia; Suguitan, Amorsolo L.; Chen, Zhongying; Paskel, Myeisha; Baz, Mariana; Moore, Ian; Jin, Hong

2017-01-01

ABSTRACT We have developed pandemic live attenuated influenza vaccines (pLAIVs) against clade 1 H5N1 viruses on an Ann Arbor cold-adapted (ca) backbone that induced long-term immune memory. In 2015, many human infections caused by a new clade (clade 2.2.1.1) of goose/Guangdong (gs/GD) lineage H5N1 viruses were reported in Egypt, which prompted updating of the H5N1 pLAIV. We explored two strategies to generate suitable pLAIVs. The first approach was to modify the hemagglutinin gene of a highly pathogenic wild-type (wt) clade 2.2.1.1 virus, A/Egypt/N03434/2009 (Egy/09) (H5N1), with its unmodified neuraminidase (NA) gene; this virus was designated Egy/09 ca. The second approach was to select a low-pathogenicity avian influenza H5 virus that elicited antibodies that cross-reacted with a broad range of H5 viruses, including the Egypt H5N1 viruses, and contained a novel NA subtype for humans. We selected the low-pathogenicity A/duck/Hokkaido/69/2000 (H5N3) (dk/Hok/00) virus for this purpose. Both candidate vaccines were attenuated and immunogenic in ferrets, inducing antibodies that neutralized homologous and heterologous H5 viruses with different degrees of cross-reactivity; Egy/09 ca vaccine antisera were more specific for the gs/GD lineage viruses but did not neutralize recent North American isolates (clade 2.3.4.4), whereas antisera from dk/Hok/69 ca-vaccinated ferrets cross-reacted with clade 2.3.4.4 and 2.2.1 viruses but not clade 1 or 2.1 viruses. When vaccinated ferrets were challenged with homologous and heterologous H5 viruses, challenge virus replication was reduced in the respiratory tract. Thus, the two H5 pLAIV candidates are suitable for clinical development to protect humans from infection with different clades of H5 viruses. IMPORTANCE In response to the continuing evolution of H5N1 avian influenza viruses and human infections, new candidate H5 live attenuated vaccines were developed by using two different approaches: one targeted a specific circulating

Development of Clade-Specific and Broadly Reactive Live Attenuated Influenza Virus Vaccines against Rapidly Evolving H5 Subtype Viruses.

PubMed

Boonnak, Kobporn; Matsuoka, Yumiko; Wang, Weijia; Suguitan, Amorsolo L; Chen, Zhongying; Paskel, Myeisha; Baz, Mariana; Moore, Ian; Jin, Hong; Subbarao, Kanta

2017-08-01

We have developed pandemic live attenuated influenza vaccines (pLAIVs) against clade 1 H5N1 viruses on an Ann Arbor cold-adapted ( ca ) backbone that induced long-term immune memory. In 2015, many human infections caused by a new clade (clade 2.2.1.1) of goose/Guangdong (gs/GD) lineage H5N1 viruses were reported in Egypt, which prompted updating of the H5N1 pLAIV. We explored two strategies to generate suitable pLAIVs. The first approach was to modify the hemagglutinin gene of a highly pathogenic wild-type ( wt ) clade 2.2.1.1 virus, A/Egypt/N03434/2009 (Egy/09) (H5N1), with its unmodified neuraminidase (NA) gene; this virus was designated Egy/09 ca The second approach was to select a low-pathogenicity avian influenza H5 virus that elicited antibodies that cross-reacted with a broad range of H5 viruses, including the Egypt H5N1 viruses, and contained a novel NA subtype for humans. We selected the low-pathogenicity A/duck/Hokkaido/69/2000 (H5N3) (dk/Hok/00) virus for this purpose. Both candidate vaccines were attenuated and immunogenic in ferrets, inducing antibodies that neutralized homologous and heterologous H5 viruses with different degrees of cross-reactivity; Egy/09 ca vaccine antisera were more specific for the gs/GD lineage viruses but did not neutralize recent North American isolates (clade 2.3.4.4), whereas antisera from dk/Hok/69 ca -vaccinated ferrets cross-reacted with clade 2.3.4.4 and 2.2.1 viruses but not clade 1 or 2.1 viruses. When vaccinated ferrets were challenged with homologous and heterologous H5 viruses, challenge virus replication was reduced in the respiratory tract. Thus, the two H5 pLAIV candidates are suitable for clinical development to protect humans from infection with different clades of H5 viruses. IMPORTANCE In response to the continuing evolution of H5N1 avian influenza viruses and human infections, new candidate H5 live attenuated vaccines were developed by using two different approaches: one targeted a specific circulating

Epidemiology of low pathogenic avian influenza viruses in wild birds.

PubMed

Fouchier, R A M; Munster, V J

2009-04-01

Although extensive data are available on low pathogenic avian influenza (LPAI) virus surveillance in wild birds in North America and Europe, data are scarce for other parts of the world, and our understanding of LPAI virus ecology in the natural reservoir is still far from complete. The outbreak of highly pathogenic avian influenza (HPAI) of the H5N1 subtype in the eastern hemisphere has put an increased focus on the role of wild birds in influenza virus transmission. Here, the authors review the current knowledge of the (molecular) epidemiology, genetics and evolution of LPAI viruses in wild birds, and identify some important gaps in current knowledge.

Type a influenza virus surveillance in free-flying, nonmigratory ducks residing on the eastern shore of Maryland

USGS Publications Warehouse

Slemons, R.D.; Hansen, W.R.; Converse, K.A.; Senne, D.A.

2003-01-01

Virus surveillance in free-flying, nonmigratory ducks living on the eastern shore of Maryland indicated that influenza A viruses were introduced into the area or that the prevalence of endemic infections increased between July 15 and August 27, 1998. Cloacal swabs collected between May 28 and July 15, 1998, were negative for influenza A virus recovery (0/233), whereas 13.9% (29/209) of swabs collected between August 27 and September 2, 1998, were positive for influenza A virus recovery. Five hemagglutinin subtypes (H2, H3, H6, H9, and H12), six neuraminidase subtypes (N1, N2, N4, N5, N6, and N8), and nine HA-NA combinations were identified among 29 influenza A isolates. Interestingly, 18 of the 29 isolates initially appeared to contain two or more HA and/or NA subtypes. The free-flying, nonmigratory ducks served as excellent sentinels for the early detection of type A influenza viruses in the southern half of the Atlantic Migratory Waterfowl Flyway during the earliest phase of the yearly southern migration.

Type A influenza virus surveillance in free-flying, nonmigratory ducks residing on the eastern shore of Maryland

USGS Publications Warehouse

Slemons, R.D.; Hansen, W.R.; Converse, K.A.; Senne, D.A.

2003-01-01

Virus surveillance in free-flying, nonmigratory ducks living on the eastern shore of Maryland indicated that influenza A viruses were introduced into the area or that the prevalence of endemic infections increased between July 15 and August 27, 1998. Cloacal swabs collected between May 28 and July 15, 1998, were negative for influenza A virus recovery (0/233), whereas 13.9% (29/209) of swabs collected between August 27 and September 2, 1998, were positive for influenza A virus recovery. Five hemagglutinin subtypes (H2, H3, H6, H9, and H12), six neuraminidase subtypes (N1, N2, N4, N5, N6, and N8), and nine HA-NA combinations were identified among 29 influenza A isolates. Interestingly, 18 of the 29 isolates initially appeared to contain two or more HA and/or NA subtypes. The free-flying, nonmigratory ducks served as excellent sentinels for the early detection of type A influenza viruses in the southern half of the Atlantic Migratory Waterfowl Flyway during the earliest phase of the yearly southern migration.

A 4-year study of avian influenza virus prevalence and subtype diversity in ducks of Newfoundland, Canada.

PubMed

Huang, Yanyan; Wille, Michelle; Dobbin, Ashley; Robertson, Gregory J; Ryan, Pierre; Ojkic, Davor; Whitney, Hugh; Lang, Andrew S

2013-10-01

The island of Newfoundland, Canada, is at the eastern edge of North America and has migratory bird connections with the continental mainland as well as across the North Atlantic Ocean. Here, we report a 4-year avian influenza virus (AIV) epidemiological study in ducks in the St. John's region of Newfoundland. The overall prevalence of AIV detection in ducks during this study was 7.2%, with American Black Ducks contributing the vast majority of the collected samples and the AIV positives. The juvenile ducks showed a significantly higher AIV detection rate (10.6%) compared with adults (3.4%). Seasonally, AIV prevalence rates were higher in the autumn (8.4%), but positives were still detected in the winter (4.6%). Preliminary serology tests showed a high incidence of previous AIV infection (20/38, 52.6%). A total of 43 viruses were characterized for their HA-NA or HA subtypes, which revealed a large diversity of AIV subtypes and little recurrence of subtypes from year to year. Investigation of the movement patterns of ducks in this region showed that it is a largely non-migratory duck population, which may contribute to the observed pattern of high AIV subtype turnover. Phylogenetic analysis of 4 H1N1 and one H5N4 AIVs showed these viruses were highly similar to other low pathogenic AIV sequences from waterfowl in North America and assigned all gene segments into American-avian clades. Notably, the H1N1 viruses, which were identified in consecutive years, possessed homologous genomes. Such detection of homologous AIV genomes across years is rare, but indicates the role of the environmental reservoir in viral perpetuation.

The pig as a mixing vessel for influenza viruses: Human and veterinary implications

PubMed Central

Ma, Wenjun; Kahn, Robert E; Richt, Juergen A

2009-01-01

Influenza A viruses are highly infectious respiratory pathogens that can infect many species. Birds are the reservoir for all known influenza A subtypes; and novel influenza viruses can emerge from birds and infect mammalian species including humans. Because swine are susceptible to infection with both avian and human influenza viruses, novel reassortant influenza viruses can be generated in this mammalian species by reassortment of influenza viral segments leading to the “mixing vessel” theory. There is no direct evidence that the reassortment events culminating in the 1918, 1957 or 1968 pandemic influenza viruses originated from pigs. Genetic reassortment among avian, human and/or swine influenza virus gene segments has occurred in pigs and some novel reassortant swine viruses have been transmitted to humans. Notably, novel reassortant H2N3 influenza viruses isolated from the US pigs, most likely infected with avian influenza viruses through surface water collected in ponds for cleaning barns and watering animals, had a similar genetic make-up to early isolates (1957) of the H2N2 human pandemic. These novel H2N3 swine viruses were able to cause disease in swine and mice and were infectious and highly transmissible in swine and ferrets without prior adaptation. The preceding example shows that pigs could transmit novel viruses from an avian reservoir to other mammalian species. Importantly, H2 viruses pose a substantial risk to humans because they have been absent from mammalian species since 1968 and people born after 1968 have little preexisting immunity to the H2 subtype. It is difficult to predict which virus will cause the next human pandemic and when that pandemic might begin. Importantly, the establishment and spread of a reassorted mammalian-adapted virus from pigs to humans could happen anywhere in the world. Therefore, both human and veterinary research needs to give more attention to potential cross-species transmission capacity of influenza A

Analysis of antigen conservation and inactivation of gamma-irradiated avian influenza virus subtype H9N2.

PubMed

Salehi, Bahareh; Motamedi-Sedeh, Farahnaz; Madadgar, Omid; Khalili, Iraj; Ghalyan Chi Langroudi, Arash; Unger, Hermann; Wijewardana, Viskam

2018-06-01

Avian influenza (AI) A subtype H9N2 virus belongs to Orthomyxoviridae family and causes low-pathogenic disease AI. The use of gamma-irradiated viral antigens has been developed in the production of effective vaccines. In this research, LPAIV H9N2 strain, A/Chicken/IRN/Ghazvin/2001, was multiplied on SPF eggs and irradiated by a Nordian gamma cell instrument. Irradiated and non-irradiated AI virus (AIV) samples were titrated by EID50 method and hemagglutinin (HA) antigen was analyzed by HA test as the WHO pattern method. Infectivity of irradiated virus was determined by egg inoculation method during four blind cultures. The results showed that after increasing the dose of gamma radiation, virus titer gradually decreased. D 10 value and optimum dose for complete virus inactivation were calculated by dose/response curve, 3.36 and 29.52 kGy, respectively. In addition, HA antigenicity of gamma-irradiated virus samples from 0 to 30 kGy was not changed. The results of safety test for gamma-irradiated AIV samples showed complete inactivation with gamma ray doses 30 and 35 kGy, without any multiplication on eggs after four blind cultures. According to the results of HA antigen assay and safety test, the gamma-irradiated and complete inactivated AIV subtype H9N2 is a good candidate as an inactivated immunogenic agent for poultry vaccination.

Pathogenicity testing of influenza candidate vaccine viruses in the ferret model.

PubMed

Belser, Jessica A; Johnson, Adam; Pulit-Penaloza, Joanna A; Pappas, Claudia; Pearce, Melissa B; Tzeng, Wen-Pin; Hossain, M Jaber; Ridenour, Callie; Wang, Li; Chen, Li-Mei; Wentworth, David E; Katz, Jacqueline M; Maines, Taronna R; Tumpey, Terrence M

2017-11-01

The development of influenza candidate vaccine viruses (CVVs) for pre-pandemic vaccine production represents a critical step in pandemic preparedness. The multiple subtypes and clades of avian or swine origin influenza viruses circulating world-wide at any one time necessitates the continuous generation of CVVs to provide an advanced starting point should a novel zoonotic virus cross the species barrier and cause a pandemic. Furthermore, the evolution and diversity of novel influenza viruses that cause zoonotic infections requires ongoing monitoring and surveillance, and, when a lack of antigenic match between circulating viruses and available CVVs is identified, the production of new CVVs. Pandemic guidelines developed by the WHO Global Influenza Program govern the design and preparation of reverse genetics-derived CVVs, which must undergo numerous safety and quality tests prior to human use. Confirmation of reassortant CVV attenuation of virulence in ferrets relative to wild-type virus represents one of these critical steps, yet there is a paucity of information available regarding the relative degree of attenuation achieved by WHO-recommended CVVs developed against novel viruses with pandemic potential. To better understand the degree of CVV attenuation in the ferret model, we examined the relative virulence of six A/Puerto Rico/8/1934-based CVVs encompassing five different influenza A subtypes (H2N3, H5N1, H5N2, H5N8, and H7N9) compared with the respective wild-type virus in ferrets. Despite varied virulence of wild-type viruses in the ferret, all CVVs examined showed reductions in morbidity and viral shedding in upper respiratory tract tissues. Furthermore, unlike the wild-type counterparts, none of the CVVs spread to extrapulmonary tissues during the acute phase of infection. While the magnitude of virus attenuation varied between virus subtypes, collectively we show the reliable and reproducible attenuation of CVVs that have the A/Puerto Rico/9/1934 backbone

Pathogenicity testing of influenza candidate vaccine viruses in the ferret model

PubMed Central

Belser, Jessica A.; Johnson, Adam; Pulit-Penaloza, Joanna A.; Pappas, Claudia; Pearce, Melissa B.; Tzeng, Wen-Pin; Hossain, M. Jaber; Ridenour, Callie; Wang, Li; Chen, Li-Mei; Wentworth, David E.; Katz, Jacqueline M.; Maines, Taronna R.; Tumpey, Terrence M.

2018-01-01

The development of influenza candidate vaccine viruses (CVVs) for pre-pandemic vaccine production represents a critical step in pandemic preparedness. The multiple subtypes and clades of avian or swine origin influenza viruses circulating world-wide at any one time necessitates the continuous generation of CVVs to provide an advanced starting point should a novel zoonotic virus cross the species barrier and cause a pandemic. Furthermore, the evolution and diversity of novel influenza viruses that cause zoonotic infections requires ongoing monitoring and surveillance, and, when a lack of antigenic match between circulating viruses and available CVVs is identified, the production of new CVVs. Pandemic guidelines developed by the WHO Global Influenza Program govern the design and preparation of reverse genetics-derived CVVs, which must undergo numerous safety and quality tests prior to human use. Confirmation of reassortant CVV attenuation of virulence in ferrets relative to wild-type virus represents one of these critical steps, yet there is a paucity of information available regarding the relative degree of attenuation achieved by WHO-recommended CVVs developed against novel viruses with pandemic potential. To better understand the degree of CVV attenuation in the ferret model, we examined the relative virulence of six A/Puerto Rico/8/1934-based CVVs encompassing five different influenza A subtypes (H2N3, H5N1, H5N2, H5N8, and H7N9) compared with the respective wild-type virus in ferrets. Despite varied virulence of wild-type viruses in the ferret, all CVVs examined showed reductions in morbidity and viral shedding in upper respiratory tract tissues. Furthermore, unlike the wild-type counterparts, none of the CVVs spread to extrapulmonary tissues during the acute phase of infection. While the magnitude of virus attenuation varied between virus subtypes, collectively we show the reliable and reproducible attenuation of CVVs that have the A/Puerto Rico/9/1934 backbone

Emergence and evolution of H10 subtype influenza viruses in poultry in China.

PubMed

Ma, Chi; Lam, Tommy Tsan-Yuk; Chai, Yujuan; Wang, Jia; Fan, Xiaohui; Hong, Wenshan; Zhang, Yu; Li, Lifeng; Liu, Yongmei; Smith, David K; Webby, Richard J; Peiris, Joseph S M; Zhu, Huachen; Guan, Yi

2015-04-01

The cases of human infections with H10N8 viruses identified in late 2013 and early 2014 in Jiangxi, China, have raised concerns over the origin, prevalence, and development of these viruses in this region. Our long-term influenza surveillance of poultry and migratory birds in southern China in the past 12 years showed that H10 influenza viruses have been introduced from migratory to domestic ducks over several winter seasons at sentinel duck farms at Poyang Lake, where domestic ducks share their water body with overwintering migratory birds. H10 viruses were never detected in terrestrial poultry in our survey areas until August 2013, when they were identified at live-poultry markets in Jiangxi. Since then, we have isolated 124 H10N8 or H10N6 viruses from chickens at local markets, revealing an ongoing outbreak. Phylogenetic analysis of H10 and related viruses showed that the chicken H10N8 viruses were generated through multiple reassortments between H10 and N8 viruses from domestic ducks and the enzootic chicken H9N2 viruses. These chicken reassortant viruses were highly similar to the human isolate, indicating that market chickens were the source of human infection. Recently, the H10 viruses further reassorted, apparently with H5N6 viruses, and generated an H10N6 variant. The emergence and prevalence of H10 viruses in chickens and the occurrence of human infections provide direct evidence of the threat from the current influenza ecosystem in China. After the outbreak of avian-origin H7N9 influenza viruses in China, fatal human infections with a novel H10N8 virus were reported. Utilizing data from 12 years of influenza surveillance in southern China, we showed that H10 viruses were regularly introduced by migratory ducks to domestic ducks on Poyang Lake, a major aggregative site of migratory birds in Asia. The H10 viruses were maintained and amplified in domestic ducks and then transmitted to chickens and reassorted with enzootic H9N2 viruses, leading to an

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

PubMed

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

2014-11-01

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

Antibody responses of raccoons naturally exposed to influenza A virus.

PubMed

Root, J Jeffrey; Bentler, Kevin T; Sullivan, Heather J; Blitvich, Bradley J; McLean, Robert G; Franklin, Alan B

2010-10-01

An investigation was performed to describe the responses of naturally acquired antibodies to influenza A virus in raccoons (Procyon lotor) over time. Seven wild raccoons, some of which had been exposed to multiple subtypes of influenza A virus, were held in captivity for 279 days, and serum samples were collected on 10 occasions during this interval. Serum samples from 9 of 10 bleeding occasions were tested using an epitope-blocking enzyme-linked immunosorbent assay for the presence of antibodies to influenza A virus. Although titer declines were noted in most animals over time, all animals maintained detectable antibodies for the duration of the study. These data indicate that naturally acquired antibodies to influenza A virus can remain detectable in raccoons for many months, with the actual duration presumably being much longer because all animals had been exposed to influenza A virus before this study commenced. This information is important to surveillance programs because the duration of naturally acquired antibodies to influenza A virus in wildlife populations is largely unknown.

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

PubMed

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

2012-09-01

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

Investigation of Influenza Virus Polymerase Activity in Pig Cells

PubMed Central

Moncorgé, Olivier; Long, Jason S.; Cauldwell, Anna V.; Zhou, Hongbo; Lycett, Samantha J.

2013-01-01

Reassortant influenza viruses with combinations of avian, human, and/or swine genomic segments have been detected frequently in pigs. As a consequence, pigs have been accused of being a “mixing vessel” for influenza viruses. This implies that pig cells support transcription and replication of avian influenza viruses, in contrast to human cells, in which most avian influenza virus polymerases display limited activity. Although influenza virus polymerase activity has been studied in human and avian cells for many years by use of a minigenome assay, similar investigations in pig cells have not been reported. We developed the first minigenome assay for pig cells and compared the activities of polymerases of avian or human influenza virus origin in pig, human, and avian cells. We also investigated in pig cells the consequences of some known mammalian host range determinants that enhance influenza virus polymerase activity in human cells, such as PB2 mutations E627K, D701N, G590S/Q591R, and T271A. The two typical avian influenza virus polymerases used in this study were poorly active in pig cells, similar to what is seen in human cells, and mutations that adapt the avian influenza virus polymerase for human cells also increased activity in pig cells. In contrast, a different pattern was observed in avian cells. Finally, highly pathogenic avian influenza virus H5N1 polymerase activity was tested because this subtype has been reported to replicate only poorly in pigs. H5N1 polymerase was active in swine cells, suggesting that other barriers restrict these viruses from becoming endemic in pigs. PMID:23077313

The future of influenza A virus vaccines for swine

USDA-ARS?s Scientific Manuscript database

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

Genome sequence of a novel H14N7 subtype influenza A virus isolated from a blue-winged teal (Anas discors) harvested in Texas, USA

USGS Publications Warehouse

Ramey, Andy M.; Reeves, Andrew; Poulson, Rebecca L.; Carter, Deborah L.; Davis-Fields, Nicholas; Stallknecht, David E.

2016-01-01

We report here the complete genome sequence of a novel H14N7 subtype influenza A virus (IAV) isolated from a blue-winged teal (Anas discors) harvested in Texas, USA. The genomic characteristics of this IAV strain with a previously undetected subtype combination suggest recent viral evolution within the New World wild-bird IAV reservoir.                   

Genetic characterization of avian influenza subtype H4N6 and H4N9 from live bird market, Thailand

USDA-ARS?s Scientific Manuscript database

A one year active surveillance program for influenza A viruses among avian species in a live-bird market (LBM) in Bangkok, Thailand was conducted in 2009. Out of 970 samples collected, influenza A virus subtypes H4N6 (n=2) and H4N9 (n=1), were isolated from healthy Muscovy ducks. All three viruses w...

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

PubMed

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

2012-01-05

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

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.

Antibody Recognition of a Highly Conserved Influenza Virus Epitope

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

Ekiert, Damian C.; Bhabha, Gira; Elsliger, Marc-André

2009-05-21

Influenza virus presents an important and persistent threat to public health worldwide, and current vaccines provide immunity to viral isolates similar to the vaccine strain. High-affinity antibodies against a conserved epitope could provide immunity to the diverse influenza subtypes and protection against future pandemic viruses. Cocrystal structures were determined at 2.2 and 2.7 angstrom resolutions for broadly neutralizing human antibody CR6261 Fab in complexes with the major surface antigen (hemagglutinin, HA) from viruses responsible for the 1918 H1N1 influenza pandemic and a recent lethal case of H5N1 avian influenza. In contrast to other structurally characterized influenza antibodies, CR6261 recognizes amore » highly conserved helical region in the membrane-proximal stem of HA1 and HA2. The antibody neutralizes the virus by blocking conformational rearrangements associated with membrane fusion. The CR6261 epitope identified here should accelerate the design and implementation of improved vaccines that can elicit CR6261-like antibodies, as well as antibody-based therapies for the treatment of influenza.« less

Surveillance of Influenza A Virus and Its Subtypes in Migratory Wild Birds of Nepal

PubMed Central

Sharma, Ajay; Bhatta, Tarka; Adhikari, Pratikshya; Sherchan, Adarsh Man; Shrestha, Bishwo; Bista, Manisha; Rajbhandari, Rajesh; Oberoi, Mohinder; Bisht, Khadak; Hero, Jean-Marc; Dissanayake, Ravi; Dhakal, Maheshwar; Hughes, Jane; Debnath, Nitish

2015-01-01

Nepal boarders India and China and all three countries lie within the Central Asian Flyway for migratory birds. Novel influenza A H7N9 caused human fatalities in China in 2013. Subclinical infections of influenza A H7N9 in birds and the potential for virus dispersal by migratory birds prompted this study to assess avian H7N9 viral intrusion into Nepal. Surveillance of influenza A virus in migratory birds was implemented in early 2014 with assistance from the Food and Agricultural Organization (FAO). Of 1811 environmental fecal samples collected from seven wetland migratory bird roosting areas, influenza A H9N2 was found in one sample from a ruddy shelduck in Koshi Tappu Wildlife Reserve located in southern Nepal. Avian H7N9 and other highly pathogenic avian influenza viruses were not detected. This study provides baseline data on the status of avian influenza virus in migratory bird populations in Nepal. PMID:26176773

Receptor mimicry by antibody F045–092 facilitates universal binding to the H3 subtype of influenza virus

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

Lee, Peter S.; Ohshima, Nobuko; Stanfield, Robyn L.

Influenza viruses present a significant health challenge each year, as in the H3N2 epidemic of 2012–2013. Here we describe an antibody, F045–092, that possesses broadly neutralizing activity against the entire H3 subtype and accommodates the natural variation and additional glycosylation in all strains tested from 1963 to 2011. Crystal structures of F045–092 in complex with HAs from 1975 and 2011 H3N2 viruses reveal the structural basis for its neutralization breadth through insertion of its 23-residue HCDR3 into the receptor-binding site that involves striking receptor mimicry. F045–092 extends its recognition to divergent subtypes, including H1, H2 and H13, using the enhancedmore » avidity of its IgG to overcome lower-affinity Fab binding, as observed with other antibodies that target the receptor-binding site. This unprecedented level of antibody cross-reactivity against the H3 subtype can potentially inform on development of a pan-H3 vaccine or small-molecule therapeutics.« less

[Molecular analyses of human influenza viruses. Circulation of new variants since 1995/96].

PubMed

Biere, B; Schweiger, B

2008-09-01

The evolution of influenza viruses is increasingly pursued by molecular analyses that complement classical methods. The analyses focus on the two surface proteins hemagglutinin (HA) and neuraminidase (NA) which determine the viral antigenic profile. Influenza A(H3N2) viruses are exceptionally variable, so that usually at least two virus variants cocirculate at the same time. Together with influenza B viruses they caused approximately 90% of influenza virus infections in Germany during the last 12 seasons, while influenza A(H1N1) viruses only played a subordinate part. Unexpectedly, reassorted viruses of subtype A(H1N2) appeared during the seasons 2001/02 and 2002/03, but were isolated only rarely and gained no epidemiological significance. Furthermore, during the season 2001/02 influenza B viruses of the Victoria-lineage reappeared in Germany and other countries of the northern hemisphere after 10 years of absence. These viruses reassorted with the cocirculating Yamagata-like influenza B viruses, as could be seen by the appearance of viruses with a Victoria-like HA and a Yamagata-like NA.

Computational approach for predicting the conserved B-cell epitopes of hemagglutinin H7 subtype influenza virus.

PubMed

Wang, Xiangyu; Sun, Qi; Ye, Zhonghua; Hua, Ying; Shao, Na; Du, Yanli; Zhang, Qiwei; Wan, Chengsong

2016-10-01

An avian-origin influenza H7N9 virus epidemic occurred in China in 2013-2014, in which >422 infected people suffered from pneumonia, respiratory distress syndrome and septic shock. H7N9 viruses belong to the H7 subtype of avian-origin influenza viruses (AIV-H7). Hemagglutinin (HA) is a vital membrane protein of AIV that has an important role in host recognition and infection. The epitopes of HA are significant determinants of the regularity of epidemic and viral mutation and recombination mechanisms. The present study aimed to predict the conserved B-cell epitopes of AIV-H7 HA using a bioinformatics approach, including the three most effective epitope prediction softwares available online: Artificial Neural Network based B-cell Epitope Prediction (ABCpred), B-cell Epitope Prediction (BepiPred) and Linear B-cell Epitope Prediction (LBtope). A total of 24 strains of Euro-Asiatic AIV-H7 that had been associated with a serious poultry pandemic or had infected humans in the past 30 years were selected to identify the conserved regions of HA. Sequences were obtained from the National Center for Biotechnology Information and Global Initiative on Sharing Avian Influenza Data databases. Using a combination of software prediction and sequence comparisons, the conserved epitopes of AIV-H7 were predicted and clarified. A total of five conserved epitopes [amino acids (aa) 37-52, 131-142, 215-234, 465-484 and 487-505] with a suitable length, high antigenicity and minimal variation were predicted and confirmed. Each obtained a score of >0.80 in ABCpred, 60% in LBtope and a level of 0.35 in Bepipred. In addition, a representative amino acid change (glutamine 235 -to-leucine 235 ) in the HA protein of the 2013 AIV-H7N9 was discovered. The strategy adopted in the present study may have profound implications on the rapid diagnosis and control of infectious disease caused by H7N9 viruses, as well as by other virulent viruses, such as the Ebola virus.

Replication and pathogenic potential of influenza A virus subtypes H3, H7, and H15 from free-range ducks in Bangladesh in mammals.

PubMed

El-Shesheny, Rabeh; Feeroz, Mohammed M; Krauss, Scott; Vogel, Peter; McKenzie, Pamela; Webby, Richard J; Webster, Robert G

2018-04-25

Surveillance of wild aquatic birds and free-range domestic ducks in the Tanguar Haor wetlands in Bangladesh has identified influenza virus subtypes H3N6, H7N1, H7N5, H7N9, and H15N9. Molecular characterization of these viruses indicates their contribution to the genesis of new genotypes of H5N1 influenza viruses from clade 2.3.2.1a that are dominant in poultry markets in Bangladesh as well as to the genesis of the highly pathogenic H5N8 virus currently causing disease outbreaks in domestic poultry in Europe and the Middle East. Therefore, we studied the antigenicity, replication, and pathogenicity of influenza viruses isolated from Tanguar Haor in the DBA/2J mouse model. All viruses replicated in the lung without prior mammalian adaptation, and H7N1 and H7N9 viruses caused 100% and 60% mortality, respectively. H7N5 viruses replicated only in the lungs, whereas H7N1 and H7N9 viruses also replicated in the heart, liver, and brain. Replication and transmission studies in mallard ducks showed that H7N1 and H7N9 viruses replicated in ducks without clinical signs of disease and shed at high titers from the cloaca of infected and contact ducks, which could facilitate virus transmission and spread. Our results indicate that H7 avian influenza viruses from free-range ducks can replicate in mammals, cause severe disease, and be efficiently transmitted to contact ducks. Our study highlights the role of free-range ducks in the spread of influenza viruses to other species in live poultry markets and the potential for these viruses to infect and cause disease in mammals.

Current situation of H9N2 subtype avian influenza in China.

PubMed

Gu, Min; Xu, Lijun; Wang, Xiaoquan; Liu, Xiufan

2017-09-15

In China, H9N2 subtype avian influenza outbreak is firstly reported in Guangdong province in 1992. Subsequently, the disease spreads into vast majority regions nationwide and has currently become endemic there. Over vicennial genetic evolution, the viral pathogenicity and transmissibility have showed an increasing trend as year goes by, posing serious threat to poultry industry. In addition, H9N2 has demonstrated significance to public health as it could not only directly infect mankind, but also donate partial or even whole cassette of internal genes to generate novel human-lethal reassortants like H5N1, H7N9, H10N8 and H5N6 viruses. In this review, we mainly focused on the epidemiological dynamics, biological characteristics, molecular phylogeny and vaccine strategy of H9N2 subtype avian influenza virus in China to present an overview of the situation of H9N2 in China.

Isolation and genetic characterization of novel reassortant H6N6 subtype avian influenza viruses isolated from chickens in eastern China.

PubMed

Wu, Haibo; Lu, Rufeng; Peng, Xiuming; Peng, Xiaorong; Cheng, Linfang; Jin, Changzhong; Lu, Xiangyun; Xie, Tiansheng; Yao, Hangping; Wu, Nanping

2016-07-01

H6 subtype avian influenza viruses (AIVs) possess the ability to cross the species barrier to infect mammals and pose a threat to human health. From June 2014 to July 2015, 12 H6N6 AIVs were isolated from chickens in live-poultry markets in Zhejiang Province, Eastern China. Phylogenetic analysis showed that these isolates received their genes from H6 and H9N2 subtype AIVs of poultry in China. These novel reassortant viruses showed moderate pathogenicity in mice and were able to replicate in mice without prior adaptation. Considering that novel reassorted H6N6 viruses were isolated from chickens in this study, it is possible that these chickens play an important role in the generation of novel reassorted H6N6 AIVs, and these results emphasize the need for continued surveillance of the H6N6 AIVs circulating in poultry.

Genetic characterization of influenza A virus subtype H12N1 isolated from a watercock and lesser whistling ducks in Thailand.

PubMed

Wongphatcharachai, Manoosak; Wisedchanwet, Trong; Lapkuntod, Jiradej; Nonthabenjawan, Nutthawan; Jairak, Waleemas; Amonsin, Alongkorn

2012-06-01

Monitoring of influenza A virus (IAV) was conducted in wild bird species in central Thailand. Four IAV subtype H12N1 strains were isolated from a watercock (order Gruiformes, family Rallidae) (n = 1) and lesser whistling ducks (order Anseriformes, family Anatidae) (n = 3). All H12N1 viruses were characterized by whole-genome sequencing. Phylogenetic analysis of all eight genes of the Thai H12N1 viruses indicated that they are most closely related to the Eurasian strains. Analysis of the HA gene revealed the strains to be of low pathogenicity. This study is the first to report the circulation of IAV subtype H12N1 in Thailand and to describe the genetic characteristics of H12N1 in Eurasia. Moreover, the genetic information obtained on H12N1 has contributed a new Eurasian strain of H12N1 to the GenBank database.

Human health implications of avian influenza viruses and paramyxoviruses.

PubMed

Capua, I; Alexander, D J

2004-01-01

Among avian influenza viruses and avian paramyxoviruses are the aetiological agents of two of the most devastating diseases of the animal kingdom: (i). the highly pathogenic form of avian influenza, caused by some viruses of the H5 and H7 subtypes, and (ii). Newcastle disease, caused by virulent strains of APMV type 1. Mortality rates due to these agents can exceed 50% in naïve bird populations, and, for some strains of AI, nearly 100%. These viruses may also be responsible for clinical conditions in humans. The virus responsible for Newcastle disease has been known to cause conjunctivitis in humans since the 1940s. The conjunctivitis is self-limiting and does not have any permanent consequences. Until 1997, reports of human infection with avian influenza viruses were sporadic and frequently associated with conjunctivitis. Recently, however, avian influenza virus infections have been associated with fatalities in human beings. These casualties have highlighted the potential risk that this type of infection poses to public health. In particular, the pathogenetic mechanisms of highly pathogenic avian influenza viruses in birds and the possibility of reassortment between avian and human viruses in the human host represent serious threats to human health. For this reason, any suspected case should be investigated thoroughly.

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.

Development of a novel rapid immunochromatographic test specific for the H5 influenza virus.

PubMed

Miyagawa, Eiji; Kogaki, Hiroyuki; Uchida, Yoshiaki; Fujii, Nobuyuki; Shirakawa, Takashi; Sakoda, Yoshihrio; Kida, Hiroshi

2011-05-01

Three anti-H5 influenza virus monoclonal antibody (mAb) clones, IFH5-26, IFH5-115 and IFH5-136, were obtained by immunising a BALB/C mouse with inactivated A/duck/Hokkaido/Vac-1/04 (H5N1). These mAbs were found to recognise specifically the haemagglutinin (HA) epitope of the influenza H5 subtypes by western blotting with recombinant HAs; however, these mAbs have no neutralising activity for A/duck/Hokkaido/84/02 (H5N3) or A/Puerto Ric/8/34 (H1N1). Each epitope of these mAbs was a conformational epitope that was formed from the regions located between 46 to 60 amino acids (aa) and 312 to 322 aa for IFH5-115, from 101 to 113 aa and 268 to 273 aa for IFH5-136 and from 61 to 80 aa and 290 to 300 aa for IFH5-26. The epitopes were located in the loop regions between the receptor region and alpha-helix structure in haemagglutinin 1 (HA1). Influenza A virus H5-specific rapid immunochromatographic test kits were tested as solid phase antibody/alkaline phosphate-conjugated mAb in the following three combinations: IFH5-26/IFH5-115, IFH5-136/IFH5-26 and IFH5-136/IFH5-115. In every combination, only influenza A H5 subtypes were detected. For effective clinical application, rapid dual discrimination immunochromatographic test kits in combination with H5 HA-specific mAb, IFA5-26 and IFA5-115 and the influenza A NP NP-specific mAb, FVA2-11, were developed. The dual discrimination immunochromatographic tests kits detected influenza A virus H5 subtypes as H5 line-positive and all influenza A subtypes as A line-positive simultaneously. The dual discrimination immunochromatographic test kits may be useful for discriminating highly pathogenic avian influenza A H5N1 viruses from seasonal influenza A virus, as well as for confirming influenza infection status in human, avian and mammalian hosts. Copyright © 2011 Elsevier B.V. All rights reserved.

Type- and Subtype-Specific Influenza Forecast.

PubMed

Kandula, Sasikiran; Yang, Wan; Shaman, Jeffrey

2017-03-01

Prediction of the growth and decline of infectious disease incidence has advanced considerably in recent years. As these forecasts improve, their public health utility should increase, particularly as interventions are developed that make explicit use of forecast information. It is the task of the research community to increase the content and improve the accuracy of these infectious disease predictions. Presently, operational real-time forecasts of total influenza incidence are produced at the municipal and state level in the United States. These forecasts are generated using ensemble simulations depicting local influenza transmission dynamics, which have been optimized prior to forecast with observations of influenza incidence and data assimilation methods. Here, we explore whether forecasts targeted to predict influenza by type and subtype during 2003-2015 in the United States were more or less accurate than forecasts targeted to predict total influenza incidence. We found that forecasts separated by type/subtype generally produced more accurate predictions and, when summed, produced more accurate predictions of total influenza incidence. These findings indicate that monitoring influenza by type and subtype not only provides more detailed observational content but supports more accurate forecasting. More accurate forecasting can help officials better respond to and plan for current and future influenza activity. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Construction and Immunogenicity Evaluation of Recombinant Influenza A Viruses Containing Chimeric Hemagglutinin Genes Derived from Genetically Divergent Influenza A H1N1 Subtype Viruses

PubMed Central

McCormick, Kara; Jiang, Zhiyong; Zhu, Longchao; Lawson, Steven R.; Langenhorst, Robert; Ransburgh, Russell; Brunick, Colin; Tracy, Miranda C.; Hurtig, Heather R.; Mabee, Leah M.; Mingo, Mark; Li, Yanhua; Webby, Richard J.

2015-01-01

Background and Objectives Influenza A viruses cause highly contagious diseases in a variety of hosts, including humans and pigs. To develop a vaccine that can be broadly effective against genetically divergent strains of the virus, in this study we employed molecular breeding (DNA shuffling) technology to create a panel of chimeric HA genes. Methods and Results Each chimeric HA gene contained genetic elements from parental swine influenza A viruses that had a history of zoonotic transmission, and also from a 2009 pandemic virus. Each parental virus represents a major phylogenetic clade of influenza A H1N1 viruses. Nine shuffled HA constructs were initially screened for immunogenicity in mice by DNA immunization, and one chimeric HA (HA-129) was expressed on both a A/Puerto Rico/8/34 backbone with mutations associated with a live, attenuated phenotype (PR8LAIV-129) and a A/swine/Texas/4199-2/98 backbone (TX98-129). When delivered to mice, the PR8LAIV-129 induced antibodies against all four parental viruses, which was similar to the breadth of immunity observed when HA-129 was delivered as a DNA vaccine. This chimeric HA was then tested as a candidate vaccine in a nursery pig model, using inactivated TX98-129 virus as the backbone. The results demonstrate that pigs immunized with HA-129 developed antibodies against all four parental viruses, as well as additional primary swine H1N1 influenza virus field isolates. Conclusion This study established a platform for creating novel genes of influenza viruses using a molecular breeding approach, which will have important applications toward future development of broadly protective influenza virus vaccines. PMID:26061265

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

PubMed

Qi, Xian; Lu, Chengping

2009-09-01

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

Phylogenetic analysis of swine influenza viruses recently isolated in Korea.

PubMed

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

2008-10-01

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

Virus-Vectored Influenza Virus Vaccines

PubMed Central

Tripp, Ralph A.; Tompkins, S. Mark

2014-01-01

Despite the availability of an inactivated vaccine that has been licensed for >50 years, the influenza virus continues to cause morbidity and mortality worldwide. Constant evolution of circulating influenza virus strains and the emergence of new strains diminishes the effectiveness of annual vaccines that rely on a match with circulating influenza strains. Thus, there is a continued need for new, efficacious vaccines conferring cross-clade protection to avoid the need for biannual reformulation of seasonal influenza vaccines. Recombinant virus-vectored vaccines are an appealing alternative to classical inactivated vaccines because virus vectors enable native expression of influenza antigens, even from virulent influenza viruses, while expressed in the context of the vector that can improve immunogenicity. In addition, a vectored vaccine often enables delivery of the vaccine to sites of inductive immunity such as the respiratory tract enabling protection from influenza virus infection. Moreover, the ability to readily manipulate virus vectors to produce novel influenza vaccines may provide the quickest path toward a universal vaccine protecting against all influenza viruses. This review will discuss experimental virus-vectored vaccines for use in humans, comparing them to licensed vaccines and the hurdles faced for licensure of these next-generation influenza virus vaccines. PMID:25105278

Highly pathogenic avian influenza virus (H5N1) in experimentally infected adult mute swans.

PubMed

Kalthoff, Donata; Breithaupt, Angele; Teifke, Jens P; Globig, Anja; Harder, Timm; Mettenleiter, Thomas C; Beer, Martin

2008-08-01

Adult, healthy mute swans were experimentally infected with highly pathogenic avian influenza virus A/Cygnus cygnus/Germany/R65/2006 subtype H5N1. Immunologically naive birds died, whereas animals with preexisting, naturally acquired avian influenza virus-specific antibodies became infected asymptomatically and shed virus. Adult mute swans are highly susceptible, excrete virus, and can be clinically protected by preexposure immunity.

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

Influenza A virus subtype H9N2 infection disrupts the composition of intestinal microbiota of chickens.

PubMed

Yitbarek, Alexander; Weese, J Scott; Alkie, Tamiru Negash; Parkinson, John; Sharif, Shayan

2018-01-01

The impact of low pathogenic influenza viruses such as subtype H9N2, which infect the respiratory and the gastrointestinal tracts of chickens, on microbial composition are not known. Twenty-day-old specific pathogen-free chickens were assigned to two treatment groups, control (uninfected) and H9N2-infected (challenged via the oral-nasal route). Fecal genomic DNA was extracted, and the V3-V4 regions of the 16S rRNA gene were sequenced using the Illumina Miseq® platform. Sequences were curated using Mothur as described in the MiSeq SOP. Infection of chickens with H9N2 resulted in an increase in phylum Proteobacteria, and differential enrichment with the genera Vampirovibrio, Pseudoflavonifractor, Ruminococcus, Clostridium cluster XIVb and Isobaculum while control chickens were differentially enriched with genera Novosphingobium, Sphingomonas, Bradyrhizobium and Bifidobacterium. Analysis of pre- and post-H9N2 infection of the same chickens showed that, before infection, the fecal microbiota was characterized by Lachnospiracea and Ruminococcaceae family and the genera Clostridium sensu stricto, Roseburia and Lachnospiraceae incertae sedis. However, post-H9N2 infection, class Deltaproteobacteria, orders Clostridiales and Bacteroidiales and the genus Alistipes were differentially enriched. Findings from the current study show that influenza virus infection in chickens results in the shift of the gut microbiota, and the disruption of the host-microbial homeostasis in the gut might be one of the mechanisms by which influenza virus infection is established in chickens. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evaluation of multiplex assay platforms for detection of influenza hemagglutinin subtype specific antibody responses.

PubMed

Li, Zhu-Nan; Weber, Kimberly M; Limmer, Rebecca A; Horne, Bobbi J; Stevens, James; Schwerzmann, Joy; Wrammert, Jens; McCausland, Megan; Phipps, Andrew J; Hancock, Kathy; Jernigan, Daniel B; Levine, Min; Katz, Jacqueline M; Miller, Joseph D

2017-05-01

Influenza hemagglutination inhibition (HI) and virus microneutralization assays (MN) are widely used for seroprevalence studies. However, these assays have limited field portability and are difficult to fully automate for high throughput laboratory testing. To address these issues, three multiplex influenza subtype-specific antibody detection assays were developed using recombinant hemagglutinin antigens in combination with Chembio, Luminex ® , and ForteBio ® platforms. Assay sensitivity, specificity, and subtype cross-reactivity were evaluated using a panel of well characterized human sera. Compared to the traditional HI, assay sensitivity ranged from 87% to 92% and assay specificity in sera collected from unexposed persons ranged from 65% to 100% across the platforms. High assay specificity (86-100%) for A(H5N1) rHA was achieved for sera from exposed or unexposed to hetorosubtype influenza HAs. In contrast, assay specificity for A(H1N1)pdm09 rHA using sera collected from A/Vietnam/1204/2004 (H5N1) vaccinees in 2008 was low (22-30%) in all platforms. Although cross-reactivity against rHA subtype proteins was observed in each assay platform, the correct subtype specific responses were identified 78%-94% of the time when paired samples were available for analysis. These results show that high throughput and portable multiplex assays that incorporate rHA can be used to identify influenza subtype specific infections. Published by Elsevier B.V.

Intercontinental circulation of human influenza A(H1N2) reassortant viruses during the 2001-2002 influenza season.

PubMed

Xu, Xiyan; Smith, Catherine B; Mungall, Bruce A; Lindstrom, Stephen E; Hall, Henrietta E; Subbarao, Kanta; Cox, Nancy J; Klimov, Alexander

2002-11-15

Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.

The genomic and epidemiological dynamics of human influenza A virus.

PubMed

Rambaut, Andrew; Pybus, Oliver G; Nelson, Martha I; Viboud, Cecile; Taubenberger, Jeffery K; Holmes, Edward C

2008-05-29

The evolutionary interaction between influenza A virus and the human immune system, manifest as 'antigenic drift' of the viral haemagglutinin, is one of the best described patterns in molecular evolution. However, little is known about the genome-scale evolutionary dynamics of this pathogen. Similarly, how genomic processes relate to global influenza epidemiology, in which the A/H3N2 and A/H1N1 subtypes co-circulate, is poorly understood. Here through an analysis of 1,302 complete viral genomes sampled from temperate populations in both hemispheres, we show that the genomic evolution of influenza A virus is characterized by a complex interplay between frequent reassortment and periodic selective sweeps. The A/H3N2 and A/H1N1 subtypes exhibit different evolutionary dynamics, with diverse lineages circulating in A/H1N1, indicative of weaker antigenic drift. These results suggest a sink-source model of viral ecology in which new lineages are seeded from a persistent influenza reservoir, which we hypothesize to be located in the tropics, to sink populations in temperate regions.

Highly pathogenic avian H5N8 influenza viruses: should we be concerned?

PubMed

Tate, M D

2018-01-01

Avian influenza A viruses pose a constant threat to global human health as sporadic infections continue to occur with associated high mortality rates. To date, a number of avian influenza virus subtypes have infected humans, including H5N1, H7N9, H9N2 and H7N7. The majority of 'bird flu' cases are thought to have arisen from direct contact with infected poultry, particularly in live markets in Asia. 1 While human cases of the H5N8 subtype have not been documented as yet, there is the potential that H5N8 viruses could acquire mutations which favour infection of human cells. There is also the possibility that novel viruses with a tropism for human cells could be generated if H5N8 should reassasort with other circulating avian viruses, such as those of the H5N1 subtype. The emergence of a novel H5N8 virus with the capability of infecting humans could have drastic consequences to global health.

Antimycotic-Antibiotic Amphotericin B Promotes Influenza Virus Replication in Cell Culture ▿

PubMed Central

Roethl, Elisabeth; Gassner, Manuela; Krenn, Brigitte M.; Romanovskaya-Romanko, Ekaterina A.; Seper, Helena; Romanova, Julia; Nakowitsch, Sabine; Sturlan, Sanda; Wolschek, Markus; Sirotkin, Alexej; Kiselev, Oleg; Muster, Thomas; Egorov, Andrej

2011-01-01

In general, antibiotics are not rated as substances that inhibit or support influenza virus replication. We describe here the enhancing effect of the polyene antibiotic amphotericin B (AmB) on influenza virus growth in Vero cells. We show that isolation rates of influenza A and B viruses from clinical samples can be dramatically enhanced by adding AmB to the culture medium. We demonstrate that AmB promotes the viral uptake and endocytic processing of the virus particles. This effect is specific for Vero and human nasal epithelial cells and was not observed in Madin-Darby canine kidney cells. The effect of AmB was subtype specific and more prominent for human seasonal influenza strains but absent for H5N1 human viruses. The AmB-enhancing effect seemed to be solely due to the viral hemagglutinin function. Our results indicate that the use of AmB may facilitate influenza virus isolation and production in Vero cells. PMID:21849438

Infectivity and transmissibility of highly pathogenic avian influenza viruses in mallards

USDA-ARS?s Scientific Manuscript database

Wild aquatic birds have been associated with the intercontinental spread of H5 subtype highly pathogenic avian influenza (HPAI) viruses, but wild waterfowl have not been implicated in the spread of other HPAI viruses. In a previous study we demonstrated that many H5 and H7 HPAI viruses could infect...

Detection of influenza A virus subtypes using a solid-phase PCR microplate chip assay.

PubMed

Sun, Xin-Cheng; Wang, YunLong; Yang, Liping; Zhang, HuiRu

2015-01-01

A rapid and sensitive microplate chip based on solid PCR was developed to identify influenza A subtypes. A simple ultraviolet cross-linking method was used to immobilize DNA probes on pretreated microplates. Solid-phase PCR was proven to be a convenient method for influenza A screening. The sensitivity of the microplate chip was 10(-3) μg/mL for the enzymatic colorimetric method and 10(-4) μg/mL for the fluorescence method. The 10 sets of primers and probes for the microplate chip were highly specific and did not interfere with each other. These results suggest that the microplate chip based on solid PCR can be used to rapidly detect universal influenza A and its subtypes. This platform can also be used to detect other pathogenic microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

Influenza-A Viruses in Ducks in Northwestern Minnesota: Fine Scale Spatial and Temporal Variation in Prevalence and Subtype Diversity

PubMed Central

Wilcox, Benjamin R.; Knutsen, Gregory A.; Berdeen, James; Goekjian, Virginia; Poulson, Rebecca; Goyal, Sagar; Sreevatsan, Srinand; Cardona, Carol; Berghaus, Roy D.; Swayne, David E.; Yabsley, Michael J.; Stallknecht, David E.

2011-01-01

Waterfowl from northwestern Minnesota were sampled by cloacal swabbing for Avian Influenza Virus (AIV) from July – October in 2007 and 2008. AIV was detected in 222 (9.1%) of 2,441 ducks in 2007 and in 438 (17.9%) of 2,452 ducks in 2008. Prevalence of AIV peaked in late summer. We detected 27 AIV subtypes during 2007 and 31 during 2008. Ten hemagglutinin (HA) subtypes were detected each year (i.e., H1, 3–8, and 10–12 during 2007; H1-8, 10 and 11 during 2008). All neuraminidase (NA) subtypes were detected during each year of the study. Subtype diversity varied between years and increased with prevalence into September. Predominant subtypes during 2007 (comprising ≥5% of subtype diversity) included H1N1, H3N6, H3N8, H4N6, H7N3, H10N7, and H11N9. Predominant subtypes during 2008 included H3N6, H3N8, H4N6, H4N8, H6N1, and H10N7. Additionally, within each HA subtype, the same predominant HA/NA subtype combinations were detected each year and included H1N1, H3N8, H4N6, H5N2, H6N1, H7N3, H8N4, H10N7, and H11N9. The H2N3 and H12N5 viruses also predominated within the H2 and H12 subtypes, respectively, but only were detected during a single year (H2 and H12 viruses were not detected during 2007 and 2008, respectively). Mallards were the predominant species sampled (63.7% of the total), and 531 AIV were isolated from this species (80.5% of the total isolates). Mallard data collected during both years adequately described the observed temporal and spatial prevalence from the total sample and also adequately represented subtype diversity. Juvenile mallards also were adequate in describing the temporal and spatial prevalence of AIV as well as subtype diversity. PMID:21931636

Characterization of Avian Influenza and Newcastle Disease Viruses from Poultry in Libya.

PubMed

Kammon, Abdulwahab; Heidari, Alireza; Dayhum, Abdunaser; Eldaghayes, Ibrahim; Sharif, Monier; Monne, Isabela; Cattoli, Giovanni; Asheg, Abdulatif; Farhat, Milad; Kraim, Elforjani

2015-09-01

On March 2013, the Libyan poultry industry faced severe outbreaks due to mixed infections of APMV-1 (Newcastle disease) and low pathogenic avian influenza (AI) of the H9N2 subtype which were causing high mortality and great economic losses. APMV-1 and H9N2 were isolated and characterized. Genetic sequencing of the APMV-1/chicken/Libya/13VIR/ 7225-1/2013 isolate revealed the presence of a velogenic APMV-1 belonging to lineage 5 (GRRRQKR*F Lin.5) or genotype VII in class II, according to the nomenclature in use. Three AI viruses of the H9N2 subtype, namely A/avian/Libya/13VIR7225-2/2013, A/avian/Libya/13VIR7225-3/2013, and A/avian/Libya/13VIR7225-5/2013, were isolated and found to belong to the G1 lineage. Analysis of amino acid sequences showed that the analyzed H9N2 viruses contained the amino acid Leu at position 226 (H3 numbering) at the receptor binding site of the HA, responsible for human virus-like receptor specificity. On March 2014, an outbreak of highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was diagnosed in a backyard poultry farm in an eastern region of Libya. The H5N1 isolate (A/chicken/Libya/14VIR2749-16/2014) was detected by real time RT-PCR (rRT-PCR). Genetic characterization of the HA gene revealed that the identified subtype was highly pathogenic, belonged to the 2.2.1 lineage, and clustered with recent Egyptian viruses. This study revealed the presence of a velogenic APMV-1 genotype and of two influenza subtypes, namely HPAI H5N1 and H9N2, which are of major interest for public and animal health. Considering these findings, more investigations must be undertaken to establish and implement adequate influenza surveillance programs; this would allow better study of the epidemiology of APMV-1 genotype VII in Libya and evaluation of the current vaccination strategies.

The susceptibility of circulating human influenza viruses to tizoxanide, the active metabolite of nitazoxanide.

PubMed

Tilmanis, Danielle; van Baalen, Carel; Oh, Ding Yuan; Rossignol, Jean-Francois; Hurt, Aeron C

2017-11-01

Nitazoxanide is a thiazolide compound that was originally developed as an anti-parasitic agent, but has recently been repurposed for the treatment of influenza virus infections. Thought to exert its anti-influenza activity via the inhibition of hemagglutinin maturation and intracellular trafficking in infected cells, the effectiveness of nitazoxanide in treating patients with non-complicated influenza is currently being assessed in phase III clinical trials. Here, we describe the susceptibility of 210 seasonal influenza viruses to tizoxanide, the active circulating metabolite of nitazoxanide. An optimised cell culture-based focus reduction assay was used to determine the susceptibility of A(H1N1)pdm09, A(H3N2), and influenza B viruses circulating in the southern hemisphere from the period March 2014 to August 2016. Tizoxanide showed potent in vitro antiviral activity against all influenza viruses tested, including neuraminidase inhibitor-resistant viruses, allowing the establishment of a baseline level of susceptibility for each subtype. Median EC 50 values (±IQR) of 0.48 μM (0.33-0.71), 0.62 μM (0.56-0.75), 0.66 μM (0.62-0.69), and 0.60 μM (0.51-0.67) were obtained for A(H1N1)pdm09, A(H3N2), B(Victoria lineage), and B(Yamagata lineage) influenza viruses respectively. There was no significant difference in the median baseline tizoxanide susceptibility for each influenza subtype tested. This is the first report on the susceptibility of circulating viruses to tizoxanide. The focus reduction assay format described is sensitive, robust, and less laborious than traditional cell based antiviral assays, making it highly suitable for the surveillance of tizoxanide susceptibility in circulating seasonal influenza viruses. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

SYBR green-based real-time reverse transcription-PCR for typing and subtyping of all hemagglutinin and neuraminidase genes of avian influenza viruses and comparison to standard serological subtyping tests.

PubMed

Tsukamoto, Kenji; Panei, Carlos Javier; Javier, Panei Carlos; Shishido, Makiko; Noguchi, Daigo; Pearce, John; Kang, Hyun-Mi; Jeong, Ok Mi; Lee, Youn-Jeong; Nakanishi, Koji; Ashizawa, Takayoshi

2012-01-01

Continuing outbreaks of H5N1 highly pathogenic (HP) avian influenza virus (AIV) infections of wild birds and poultry worldwide emphasize the need for global surveillance of wild birds. To support the future surveillance activities, we developed a SYBR green-based, real-time reverse transcriptase PCR (rRT-PCR) for detecting nucleoprotein (NP) genes and subtyping 16 hemagglutinin (HA) and 9 neuraminidase (NA) genes simultaneously. Primers were improved by focusing on Eurasian or North American lineage genes; the number of mixed-base positions per primer was set to five or fewer, and the concentration of each primer set was optimized empirically. Also, 30 cycles of amplification of 1:10 dilutions of cDNAs from cultured viruses effectively reduced minor cross- or nonspecific reactions. Under these conditions, 346 HA and 345 NA genes of 349 AIVs were detected, with average sensitivities of NP, HA, and NA genes of 10(1.5), 10(2.3), and 10(3.1) 50% egg infective doses, respectively. Utility of rRT-PCR for subtyping AIVs was compared with that of current standard serological tests by using 104 recent migratory duck virus isolates. As a result, all HA genes and 99% of the NA genes were genetically subtyped, while only 45% of HA genes and 74% of NA genes were serologically subtyped. Additionally, direct subtyping of AIVs in fecal samples was possible by 40 cycles of amplification: approximately 70% of HA and NA genes of NP gene-positive samples were successfully subtyped. This validation study indicates that rRT-PCR with optimized primers and reaction conditions is a powerful tool for subtyping varied AIVs in clinical and cultured samples.

Trends in global warming and evolution of nucleoproteins from influenza A viruses since 1918.

PubMed

Yan, S; Wu, G

2010-12-01

Global warming affects not only the environment where we live, but also all living species to different degree, including influenza A virus. We recently conducted several studies on the possible impact of global warming on the protein families of influenza A virus. More studies are needed in order to have a full picture of the impact of global warming on living organisms, especially its effect on viruses. In this study, we correlate trends in global warming with evolution of the nucleoprotein from influenza A virus and then analyse the trends with respect to northern/southern hemispheres, virus subtypes and sampling species. The results suggest that global warming may have an impact on the evolution of the nucleoprotein from influenza A virus. © 2010 Blackwell Verlag GmbH.

A Single Dose of an Avian H3N8 Influenza Virus Vaccine Is Highly Immunogenic and Efficacious against a Recently Emerged Seal Influenza Virus in Mice and Ferrets

PubMed Central

Baz, Mariana; Paskel, Myeisha; Matsuoka, Yumiko; Zengel, James R.; Cheng, Xing; Treanor, John J.; Jin, Hong

2015-01-01

ABSTRACT H3N8 influenza viruses are a commonly found subtype in wild birds, usually causing mild or no disease in infected birds. However, they have crossed the species barrier and have been associated with outbreaks in dogs, pigs, donkeys, and seals and therefore pose a threat to humans. A live attenuated, cold-adapted (ca) H3N8 vaccine virus was generated by reverse genetics using the wild-type (wt) hemagglutinin (HA) and neuraminidase (NA) genes from the A/blue-winged teal/Texas/Sg-00079/2007 (H3N8) (tl/TX/079/07) wt virus and the six internal protein gene segments from the ca influenza A virus vaccine donor strain, A/Ann Arbor/6/60 ca (H2N2), the backbone of the licensed seasonal live attenuated influenza vaccine. One dose of the tl/TX/079/07 ca vaccine induced a robust neutralizing antibody response against the homologous (tl/TX/079/07) and two heterologous influenza viruses, including the recently emerged A/harbor seal/New Hampshire/179629/2011 (H3N8) and A/northern pintail/Alaska/44228-129/2006 (H3N8) viruses, and conferred robust protection against the homologous and heterologous influenza viruses. We also analyzed human sera against the tl/TX/079/07 H3N8 avian influenza virus and observed low but detectable antibody reactivity in elderly subjects, suggesting that older H3N2 influenza viruses confer some cross-reactive antibody. The latter observation was confirmed in a ferret study. The safety, immunogenicity, and efficacy of the tl/TX/079/07 ca vaccine in mice and ferrets support further evaluation of this vaccine in humans for use in the event of transmission of an H3N8 avian influenza virus to humans. The human and ferret serology data suggest that a single dose of the vaccine may be sufficient in older subjects. IMPORTANCE Although natural infection of humans with an avian H3N8 influenza virus has not yet been reported, this influenza virus subtype has already crossed the species barrier and productively infected mammals. Pandemic preparedness is an

Transmission of an H5N8-Subtype Highly Pathogenic Avian Influenza Virus from Infected Hens to Laid Eggs.

PubMed

Uchida, Yuko; Takemae, Nobuhiro; Tanikawa, Taichiro; Kanehira, Katsushi; Saito, Takehiko

2016-06-01

We showed here that an H5N8-subtype highly pathogenic avian influenza virus (HPAIV) was transmitted to both the internal contents and shells of eggs laid by white leghorn hens experimentally infected with the virus. Seven of eight HPAIV-infected hens laid eggs until 4 days postinoculation (dpi). The mean number of eggs laid per head daily decreased significantly from 0.58 before inoculation to 0.18 after viral inoculation. The virus was detected in the eggs laid by three of the seven hens. Viral transmission was detectable beginning on 3 dpi, and virus titers in tracheal and cloacal swabs from the hens that laid the contaminated eggs exceeded 2.9 log10 EID50. The level of viral replication and its timing when virus replicates enough to be detected in oviduct after virus inoculation appear to be key factors in the transmission of H5N8 HPAIV from infected hens to laid eggs.

Characterization of Low Pathogenic Avian Influenza Virus Subtype H9N2 Isolated from Free-Living Mynah Birds (Acridotheres tristis) in the Sultanate of Oman.

PubMed

Body, Mohammad H; Alrarawahi, Abdulmajeed H; Alhubsy, Saif S; Saravanan, Nirmala; Rajmony, Sunil; Mansoor, Muhammad Khalid

2015-06-01

A low pathogenic avian influenza virus was identified from free-living birds (mynah, Acridotheres tristis) of the starling family. Virus was isolated by inoculation of homogenized suspension from lung, tracheal, spleen, and cloacal swabs into the allantoic cavity of embryonated chicken eggs. Subtype of the isolate was characterized as H9N2 by hemagglutination inhibition test using monospecific chicken antisera to a wide range of influenza reference strain. Pathogenicity of the isolate was determined by intravenous pathogenicity index. The virus was reisolated from experimentally infected chicken. Additionally, the isolate was subjected to reverse transcriptase PCR using partial hemagglutinin (HA) gene-specific primers and yielded an amplicon of 487 bp. HA gene sequence analysis revealed 99% sequence homology among mynah and chicken isolates from Oman. On phylogenetic analysis, isolates from mynah (A/mynnah/Oman/AIVS6/2005) and chicken (A/chicken/Oman/AIVS3/2006; A/chicken/Oman/AIVS7/2006) clustered together tightly, indicating these free-flying birds may be a source of introduction of H9N2 subtype in poultry bird in Oman. Moreover, the HA gene of H9N2 isolates from Oman resembled those of viruses of the G1-like lineage and were very similar to those from United Arab Emirates.

Drug resistance in influenza A virus: the epidemiology and management.

PubMed

Hussain, Mazhar; Galvin, Henry D; Haw, Tatt Y; Nutsford, Ashley N; Husain, Matloob

2017-01-01

Influenza A virus (IAV) is the sole cause of the unpredictable influenza pandemics and deadly zoonotic outbreaks and constitutes at least half of the cause of regular annual influenza epidemics in humans. Two classes of anti-IAV drugs, adamantanes and neuraminidase (NA) inhibitors (NAIs) targeting the viral components M2 ion channel and NA, respectively, have been approved to treat IAV infections. However, IAV rapidly acquired resistance against both classes of drugs by mutating these viral components. The adamantane-resistant IAV has established itself in nature, and a majority of the IAV subtypes, especially the most common H1N1 and H3N2, circulating globally are resistant to adamantanes. Consequently, adamantanes have become practically obsolete as anti-IAV drugs. Similarly, up to 100% of the globally circulating IAV H1N1 subtypes were resistant to oseltamivir, the most commonly used NAI, until 2009. However, the 2009 pandemic IAV H1N1 subtype, which was sensitive to NAIs and has now become one of the dominant seasonal influenza virus strains, has replaced the pre-2009 oseltamivir-resistant H1N1 variants. This review traces the epidemiology of both adamantane- and NAI-resistant IAV subtypes since the approval of these drugs and highlights the susceptibility status of currently circulating IAV subtypes to NAIs. Further, it provides an overview of currently and soon to be available control measures to manage current and emerging drug-resistant IAV. Finally, this review outlines the research directions that should be undertaken to manage the circulation of IAV in intermediate hosts and develop effective and alternative anti-IAV therapies.

Drug resistance in influenza A virus: the epidemiology and management

PubMed Central

Hussain, Mazhar; Galvin, Henry D; Haw, Tatt Y; Nutsford, Ashley N; Husain, Matloob

2017-01-01

Influenza A virus (IAV) is the sole cause of the unpredictable influenza pandemics and deadly zoonotic outbreaks and constitutes at least half of the cause of regular annual influenza epidemics in humans. Two classes of anti-IAV drugs, adamantanes and neuraminidase (NA) inhibitors (NAIs) targeting the viral components M2 ion channel and NA, respectively, have been approved to treat IAV infections. However, IAV rapidly acquired resistance against both classes of drugs by mutating these viral components. The adamantane-resistant IAV has established itself in nature, and a majority of the IAV subtypes, especially the most common H1N1 and H3N2, circulating globally are resistant to adamantanes. Consequently, adamantanes have become practically obsolete as anti-IAV drugs. Similarly, up to 100% of the globally circulating IAV H1N1 subtypes were resistant to oseltamivir, the most commonly used NAI, until 2009. However, the 2009 pandemic IAV H1N1 subtype, which was sensitive to NAIs and has now become one of the dominant seasonal influenza virus strains, has replaced the pre-2009 oseltamivir-resistant H1N1 variants. This review traces the epidemiology of both adamantane- and NAI-resistant IAV subtypes since the approval of these drugs and highlights the susceptibility status of currently circulating IAV subtypes to NAIs. Further, it provides an overview of currently and soon to be available control measures to manage current and emerging drug-resistant IAV. Finally, this review outlines the research directions that should be undertaken to manage the circulation of IAV in intermediate hosts and develop effective and alternative anti-IAV therapies. PMID:28458567

Avian influenza virus (H5N1): a threat to human health.

PubMed

Peiris, J S Malik; de Jong, Menno D; Guan, Yi

2007-04-01

Pandemic influenza virus has its origins in avian influenza viruses. The highly pathogenic avian influenza virus subtype H5N1 is already panzootic in poultry, with attendant economic consequences. It continues to cross species barriers to infect humans and other mammals, often with fatal outcomes. Therefore, H5N1 virus has rightly received attention as a potential pandemic threat. However, it is noted that the pandemics of 1957 and 1968 did not arise from highly pathogenic influenza viruses, and the next pandemic may well arise from a low-pathogenicity virus. The rationale for particular concern about an H5N1 pandemic is not its inevitability but its potential severity. An H5N1 pandemic is an event of low probability but one of high human health impact and poses a predicament for public health. Here, we review the ecology and evolution of highly pathogenic avian influenza H5N1 viruses, assess the pandemic risk, and address aspects of human H5N1 disease in relation to its epidemiology, clinical presentation, pathogenesis, diagnosis, and management.

Human Monoclonal Antibody 81.39a Effectively Neutralizes Emerging Influenza A Viruses of Group 1 and 2 Hemagglutinins

PubMed Central

Marjuki, Henju; Mishin, Vasiliy P.; Chai, Ning; Tan, Man-Wah; Newton, Elizabeth M.; Tegeris, John; Erlandson, Karl; Willis, Melissa; Jones, Joyce; Davis, Todd; Stevens, James

2016-01-01

ABSTRACT The pandemic threat posed by emerging zoonotic influenza A viruses necessitates development of antiviral agents effective against various antigenic subtypes. Human monoclonal antibody (hMAb) targeting the hemagglutinin (HA) stalk offers a promising approach to control influenza virus infections. Here, we investigated the ability of the hMAb 81.39a to inhibit in vitro replication of human and zoonotic viruses, representing 16 HA subtypes. The majority of viruses were effectively neutralized by 81.39a at a 50% effective concentration (EC50) of <0.01 to 4.9 μg/ml. Among group 2 HA viruses tested, a single A(H7N9) virus was not neutralized at 50 μg/ml; it contained HA2-Asp19Gly, an amino acid position previously associated with resistance to neutralization by the group 2 HA-neutralizing MAb CR8020. Notably, among group 1 HA viruses, H11-H13 and H16 subtypes were not neutralized at 50 μg/ml; they shared the substitution HA2-Asp19Asn/Ala. Conversely, H9 viruses harboring HA2-Asp19Ala were fully susceptible to neutralization. Therefore, amino acid variance at HA2-Asp19 has subtype-specific adverse effects on in vitro neutralization. Mice given a single injection (15 or 45 mg/kg of body weight) at 24 or 48 h after infection with recently emerged A(H5N2), A(H5N8), A(H6N1), or A(H7N9) viruses were protected from mortality and showed drastically reduced lung viral titers. Furthermore, 81.39a protected mice infected with A(H7N9) harboring HA2-Asp19Gly, although the antiviral effect was lessened. A(H1N1)pdm09-infected ferrets receiving a single dose (25 mg/kg) had reduced viral titers and showed less lung tissue injury, despite 24- to 72-h-delayed treatment. Taken together, this study provides experimental evidence for the therapeutic potential of 81.39a against diverse influenza A viruses. IMPORTANCE Zoonotic influenza viruses, such as A(H5N1) and A(H7N9) subtypes, have caused severe disease and deaths in humans, raising public health concerns. Development of novel

2009 Pandemic Influenza A Virus Subtype H1N1 in Morocco, 2009–2010: Epidemiology, Transmissibility, and Factors Associated With Fatal Cases

PubMed Central

Barakat, Amal; Ihazmad, Hassan; El Falaki, Fatima; Tempia, Stefano; Cherkaoui, Imad; El Aouad, Rajae

2012-01-01

Background. Following the emergence of 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) in the United States and Mexico in April 2009, A(H1N1)pdm09 spread rapidly all over the world. There is a dearth of information about the epidemiology of A(H1N1)pdm09 in Africa, including Morocco. We describe the epidemiologic characteristics of the A(H1N1)pdm09 epidemic in Morocco during 2009–2010, including transmissibility and risk factors associated with fatal disease. Methods. We implemented influenza surveillance for patients presenting with influenza-like illness (ILI) at 136 private and public clinics for patients with severe acute respiratory illness (SARI) at 16 regional public hospitals from June 2009 through February 2010. Respiratory samples and structured questionnaires were collected from all enrolled patients, and samples were tested by real-time reverse-transcription polymerase chain reaction for influenza viruses. We estimated the risk factors associated with fatal disease as well as the basic reproduction number (R0) and the serial interval of the pandemic virus. Results. From June 2009 through February 2010, we obtained 3937 specimens, of which 1452 tested positive for influenza virus. Of these, 1398 (96%) were A(H1N1)pdm09. Forty percent of specimens from ILI cases (1056 of 2646) and 27% from SARI cases (342 of 1291) were positive for A(H1N1)pdm09. Sixty-four deaths occurred among laboratory-confirmed A(H1N1)pdm09 SARI cases. Among these cases, those who had hypertension (age-adjusted odd ratio [aOR], 28.2; 95% confidence interval [CI], 2.0–398.7), had neurological disorders (aOR, 7.5; 95% CI, 1.5–36.4), or were obese (aOR, 7.1; 95% CI, 1.6–31.1), as well as women of gestational age who were pregnant (aOR, 2.5; 95% CI, 1.1–5.6), were at increased risk of death. Across the country, elevated numbers of locally acquired infections were detected 4 months after the detection of the first laboratory-confirmed case and coincided with the

Age and secular distributions of virus-proven influenza patients in successive epidemics 1961-1976 in Cirencester: epidemiological significance discussed.

PubMed Central

Hope-Simpson, R. E.

1984-01-01

A general practice population of around 3900, under continuous clinical and laboratory surveillance, experienced 20 outbreaks of influenza between March 1960 and March 1976. Four epidemics were caused by subtype H2N2 type A viruses, seven by subtype H3N2 type A viruses and nine outbreaks by type B viruses. The age of every person proved virologically to have influenza is related to the age structure of the community and to the phase of the epidemic in which the virus-positive specimens were collected. Children 0-15 years old suffered a higher incidence rate than adults 16-90+. Pre-school children 0-4 suffered the highest rate of infection by viruses of both influenza A subtypes, whereas older schoolchildren 10-15 suffered the highest rate of type B infections. Despite these high incidence rates neither pre-school nor schoolchildren appear to have been the major disseminators of any of these influenza viruses in the community. Adults of all ages suffered a high rate of infection even into extreme old age, and the indiscriminate age distribution among adults was sustained in the successive epidemics. Such age-patterns are not those caused by a highly infectious immunizing virus surviving by means of direct transmissions from the sick, whose prompt development of the disease continues endless chains of transmissions. An alternative epidemic mechanism--whereby the virus does not spread from the sick but becomes latent in them, reactivating seasonally so that they later infect their companions--would produce age patterns similar to those recorded here for influenza patients. The suggested mechanism is illustrated by a simple conceptual model and the influenzal age patterns are discussed in relation to the recycling of influenza A subtypes. PMID:6736641

Cloned Defective Interfering Influenza RNA and a Possible Pan-Specific Treatment of Respiratory Virus Diseases

PubMed Central

Dimmock, Nigel J.; Easton, Andrew J.

2015-01-01

Defective interfering (DI) genomes are characterised by their ability to interfere with the replication of the virus from which they were derived, and other genetically compatible viruses. DI genomes are synthesized by nearly all known viruses and represent a vast natural reservoir of antivirals that can potentially be exploited for use in the clinic. This review describes the application of DI virus to protect from virus-associated diseases in vivo using as an example a highly active cloned influenza A DI genome and virus that protects broadly in preclinical trials against different subtypes of influenza A and against non-influenza A respiratory viruses. This influenza A-derived DI genome protects by two totally different mechanisms: molecular interference with influenza A replication and by stimulating innate immunity that acts against non-influenza A viruses. The review considers what is needed to develop DI genomes to the point of entry into clinical trials. PMID:26184282

Sequential Infection in Ferrets with Antigenically Distinct Seasonal H1N1 Influenza Viruses Boosts Hemagglutinin Stalk-Specific Antibodies

PubMed Central

Kirchenbaum, Greg A.; Carter, Donald M.

2015-01-01

ABSTRACT Broadly reactive antibodies targeting the conserved hemagglutinin (HA) stalk region are elicited following sequential infection or vaccination with influenza viruses belonging to divergent subtypes and/or expressing antigenically distinct HA globular head domains. Here, we demonstrate, through the use of novel chimeric HA proteins and competitive binding assays, that sequential infection of ferrets with antigenically distinct seasonal H1N1 (sH1N1) influenza virus isolates induced an HA stalk-specific antibody response. Additionally, stalk-specific antibody titers were boosted following sequential infection with antigenically distinct sH1N1 isolates in spite of preexisting, cross-reactive, HA-specific antibody titers. Despite a decline in stalk-specific serum antibody titers, sequential sH1N1 influenza virus-infected ferrets were protected from challenge with a novel H1N1 influenza virus (A/California/07/2009), and these ferrets poorly transmitted the virus to naive contacts. Collectively, these findings indicate that HA stalk-specific antibodies are commonly elicited in ferrets following sequential infection with antigenically distinct sH1N1 influenza virus isolates lacking HA receptor-binding site cross-reactivity and can protect ferrets against a pathogenic novel H1N1 virus. IMPORTANCE The influenza virus hemagglutinin (HA) is a major target of the humoral immune response following infection and/or seasonal vaccination. While antibodies targeting the receptor-binding pocket of HA possess strong neutralization capacities, these antibodies are largely strain specific and do not confer protection against antigenic drift variant or novel HA subtype-expressing viruses. In contrast, antibodies targeting the conserved stalk region of HA exhibit broader reactivity among viruses within and among influenza virus subtypes. Here, we show that sequential infection of ferrets with antigenically distinct seasonal H1N1 influenza viruses boosts the antibody responses

Novel Reassortant Clade 2.3.4.4 Avian Influenza A(H5N8) Virus in Wild Aquatic Birds, Russia, 2016.

PubMed

Lee, Dong-Hun; Sharshov, Kirill; Swayne, David E; Kurskaya, Olga; Sobolev, Ivan; Kabilov, Marsel; Alekseev, Alexander; Irza, Victor; Shestopalov, Alexander

2017-02-01

The emergence of novel avian influenza viruses in migratory birds is of concern because of the potential for virus dissemination during fall migration. We report the identification of novel highly pathogenic avian influenza viruses of subtype H5N8, clade 2.3.4.4, and their reassortment with other avian influenza viruses in waterfowl and shorebirds of Siberia.

Molecular Characteristics of Influenza Virus Type B Lineages Circulating in Poland.

PubMed

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

2016-01-01

From the time of the Hong Kong pandemic of 1968-1969, vaccines against influenza are trivalent, containing two subtypes of influenza type A: A/H1N1/ and A/H3N2/, and influenza type B. In 1980, circulation of the new Yamagata and Victoria lineages of influenza B virus was noted. Since both lineages have continued to circulate, the second lineage of influenza B was included into the trivalent vaccine as of the 2013/2014 epidemic season. In Poland, co-circulation of influenza type A and B has been registered over many seasons, although type A has predominated. According to the ACIP recommendations, quadrivalent vaccines against influenza are administered in some continents due to circulation of the B-Yamagata and B-Victoria lineages. Currently, only trivalent vaccines against influenza are available in Poland. The aim of the present research was to determine which of the two influenza type B lineages, or possibly both, would be isolated in Poland. The study was conducted with the use of RT-PCR. Generally, in the 2014/2015 epidemic season in Poland, circulation of type B virus was confirmed in 34 % of influenza cases. A total of 89 specimens of influenza B were tested, including co-infections of influenza B with influenza A subtypes: A/H1N1/pdm09 and A/H3N2/. The findings were that only lineage B-Yamagata circulates in the Polish population. Therefore, vaccines available on the Polish market do not require the introduction of a fourth component.

SYBR green-based real-time reverse transcription-PCR for typing and subtyping of all hemagglutinin and neuraminidase genes of avian influenza viruses and comparison to standard serological subtyping tests

USGS Publications Warehouse

Tsukamoto, K.; Javier, P.C.; Shishido, M.; Noguchi, D.; Pearce, J.; Kang, H.-M.; Jeong, O.M.; Lee, Y.-J.; Nakanishi, K.; Ashizawa, T.

2012-01-01

Continuing outbreaks of H5N1 highly pathogenic (HP) avian influenza virus (AIV) infections of wild birds and poultry worldwide emphasize the need for global surveillance of wild birds. To support the future surveillance activities, we developed a SYBR green-based, real-time reverse transcriptase PCR (rRT-PCR) for detecting nucleoprotein (NP) genes and subtyping 16 hemagglutinin (HA) and 9 neuraminidase (NA) genes simultaneously. Primers were improved by focusing on Eurasian or North American lineage genes; the number of mixed-base positions per primer was set to five or fewer, and the concentration of each primer set was optimized empirically. Also, 30 cycles of amplification of 1:10 dilutions of cDNAs from cultured viruses effectively reduced minor cross- or nonspecific reactions. Under these conditions, 346 HA and 345 NA genes of 349 AIVs were detected, with average sensitivities of NP, HA, and NA genes of 10 1.5, 10 2.3, and 10 3.1 50% egg infective doses, respectively. Utility of rRT-PCR for subtyping AIVs was compared with that of current standard serological tests by using 104 recent migratory duck virus isolates. As a result, all HA genes and 99% of the NA genes were genetically subtyped, while only 45% of HA genes and 74% of NA genes were serologically subtyped. Additionally, direct subtyping of AIVs in fecal samples was possible by 40 cycles of amplification: approximately 70% of HA and NA genes of NP gene-positive samples were successfully subtyped. This validation study indicates that rRT-PCR with optimized primers and reaction conditions is a powerful tool for subtyping varied AIVs in clinical and cultured samples. Copyright ?? 2012, American Society for Microbiology. All Rights Reserved.

Global Surveillance of Emerging Influenza Virus Genotypes by Mass Spectrometry

PubMed Central

Sampath, Rangarajan; Russell, Kevin L.; Massire, Christian; Eshoo, Mark W.; Harpin, Vanessa; Blyn, Lawrence B.; Melton, Rachael; Ivy, Cristina; Pennella, Thuy; Li, Feng; Levene, Harold; Hall, Thomas A.; Libby, Brian; Fan, Nancy; Walcott, Demetrius J.; Ranken, Raymond; Pear, Michael; Schink, Amy; Gutierrez, Jose; Drader, Jared; Moore, David; Metzgar, David; Addington, Lynda; Rothman, Richard; Gaydos, Charlotte A.; Yang, Samuel; St. George, Kirsten; Fuschino, Meghan E.; Dean, Amy B.; Stallknecht, David E.; Goekjian, Ginger; Yingst, Samuel; Monteville, Marshall; Saad, Magdi D.; Whitehouse, Chris A.; Baldwin, Carson; Rudnick, Karl H.; Hofstadler, Steven A.; Lemon, Stanley M.; Ecker, David J.

2007-01-01

Background Effective influenza surveillance requires new methods capable of rapid and inexpensive genomic analysis of evolving viral species for pandemic preparedness, to understand the evolution of circulating viral species, and for vaccine strain selection. We have developed one such approach based on previously described broad-range reverse transcription PCR/electrospray ionization mass spectrometry (RT-PCR/ESI-MS) technology. Methods and Principal Findings Analysis of base compositions of RT-PCR amplicons from influenza core gene segments (PB1, PB2, PA, M, NS, NP) are used to provide sub-species identification and infer influenza virus H and N subtypes. Using this approach, we detected and correctly identified 92 mammalian and avian influenza isolates, representing 30 different H and N types, including 29 avian H5N1 isolates. Further, direct analysis of 656 human clinical respiratory specimens collected over a seven-year period (1999–2006) showed correct identification of the viral species and subtypes with >97% sensitivity and specificity. Base composition derived clusters inferred from this analysis showed 100% concordance to previously established clades. Ongoing surveillance of samples from the recent influenza virus seasons (2005–2006) showed evidence for emergence and establishment of new genotypes of circulating H3N2 strains worldwide. Mixed viral quasispecies were found in approximately 1% of these recent samples providing a view into viral evolution. Conclusion/Significance Thus, rapid RT-PCR/ESI-MS analysis can be used to simultaneously identify all species of influenza viruses with clade-level resolution, identify mixed viral populations and monitor global spread and emergence of novel viral genotypes. This high-throughput method promises to become an integral component of influenza surveillance. PMID:17534439

Mucosal Immunization with a Candidate Universal Influenza Vaccine Reduces Virus Transmission in a Mouse Model

PubMed Central

Lo, Chia-Yun; Misplon, Julia A.; Epstein, Suzanne L.

2014-01-01

ABSTRACT Pandemic influenza is a major public health concern, but conventional strain-matched vaccines are unavailable early in a pandemic. Candidate “universal” vaccines targeting the viral antigens nucleoprotein (NP) and matrix 2 (M2), which are conserved among all influenza A virus strains and subtypes, could be manufactured in advance for use at the onset of a pandemic. These vaccines do not prevent infection but can reduce disease severity, deaths, and virus titers in the respiratory tract. We hypothesized that such immunization may reduce virus transmission from vaccinated, infected animals. To investigate this hypothesis, we studied mouse models for direct-contact and airborne transmission of H1N1 and H3N2 influenza viruses. We established conditions under which virus transmission occurs and showed that transmission efficiency is determined in part at the level of host susceptibility to infection. Our findings indicate that virus transmission between mice has both airborne and direct-contact components. Finally, we demonstrated that immunization with recombinant adenovirus vectors expressing NP and M2 significantly reduced the transmission of virus to cohoused, unimmunized mice in comparison to controls. These findings have broad implications for the impact of conserved-antigen vaccines, not only in protecting the vaccinated individual but also in protecting others by limiting influenza virus transmission and potentially reducing the size of epidemics. IMPORTANCE Using a mouse model of influenza A virus transmission, we demonstrate that a candidate “universal” influenza vaccine both protects vaccinated animals from lethal infection and reduces the transmission of virus from vaccinated to nonvaccinated mice. This vaccine induces immunity against proteins conserved among all known influenza A virus strains and subtypes, so it could be used early in a pandemic before conventional strain-matched vaccines are available and could potentially reduce the

Emerging influenza viruses and the prospect of a universal influenza virus vaccine.

PubMed

Krammer, Florian

2015-05-01

Influenza viruses cause annual seasonal epidemics and pandemics at irregular intervals. Several cases of human infections with avian and swine influenza viruses have been detected recently, warranting enhanced surveillance and the development of more effective countermeasures to address the pandemic potential of these viruses. The most effective countermeasure against influenza virus infection is the use of prophylactic vaccines. However, vaccines that are currently in use for seasonal influenza viruses have to be re-formulated and re-administered in a cumbersome process every year due to the antigenic drift of the virus. Furthermore, current seasonal vaccines are ineffective against novel pandemic strains. This paper reviews zoonotic influenza viruses with pandemic potential and technological advances towards better vaccines that induce broad and long lasting protection from influenza virus infection. Recent efforts have focused on the development of broadly protective/universal influenza virus vaccines that can provide immunity against drifted seasonal influenza virus strains but also against potential pandemic viruses. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cardiac complications associated with the influenza viruses A subtype H7N9 or pandemic H1N1 in critically ill patients under intensive care.

PubMed

Wang, Jiajia; Xu, Hua; Yang, Xinjing; Zhao, Daguo; Liu, Shenglan; Sun, Xue; Huang, Jian-An; Guo, Qiang

The clinical presentations and disease courses of patients hospitalized with either influenza A virus subtype H7N9 (H7N9) or 2009 pandemic H1N1 influenza virus were compared in a recent report, but associated cardiac complications remain unclear. The present retrospective study investigated whether cardiac complications in critically ill patients with H7N9 infections differed from those infected with the pandemic H1N1 influenza virus strain. Suspect cases were confirmed by reverse transcription polymerase chain reaction assays with specific confirmation of the pandemic H1N1 strain at the Centers for Disease Control and Prevention. Comparisons were conducted at the individual-level data of critically ill patients hospitalized with H7N9 (n=24) or pandemic H1N1 influenza virus (n=22) infections in Suzhou, China. Changes in cardiac biochemical markers, echocardiography, and electrocardiography during hospitalization in the intensive care unit were considered signs of cardiac complications. The following findings were more common among the H7N9 group relative to the pandemic H1N1 influenza virus group: greater tricuspid regurgitation pressure gradient, sinus tachycardia (heartbeat≥130bpm), ST segment depression, right ventricular dysfunction, and elevated cardiac biochemical markers. Pericardial effusion was more often found among pandemic H1N1 influenza virus patients than in the H7N9 group. In both groups, most of the cardiac complications were detected from day 6 to 14 after the onset of influenza symptoms. Those who developed cardiac complications were especially vulnerable during the first four days after initiation of mechanical ventilation. Cardiac complications were reversible in the vast majority of discharged H7N9 patients. Critically ill hospitalized H7N9 patients experienced a higher rate of cardiac complications than did patients with 2009 pandemic H1N1 influenza virus infections, with the exception of pericardial effusion. This study may help in the

Complete genome sequence of a novel H9N2 subtype influenza virus FJG9 strain in china reveals a natural reassortant event

USDA-ARS?s Scientific Manuscript database

A Chicken/FJ/G9/09 (FJ/G9) is an H9N2 subtype strain of avian influenza virus (H9N2 AIV) strain causing high morbidity, that was isolated from broilers in Fujian province, China, in 2009. The FJ/G9 has been used as the vaccine strain against H9N2 AIV infection in Fujian Province of China. Here, we r...

A duplex real-time RT-PCR assay for detecting H5N1 avian influenza virus and pandemic H1N1 influenza virus.

PubMed

Kang, Xiao-ping; Jiang, Tao; Li, Yong-qiang; Lin, Fang; Liu, Hong; Chang, Guo-hui; Zhu, Qing-yu; Qin, E-de; Qin, Cheng-feng; Yang, Yin-hui

2010-06-02

A duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay was improved for simultaneous detection of highly pathogenic H5N1 avian influenza virus and pandemic H1N1 (2009) influenza virus, which is suitable for early diagnosis of influenza-like patients and for epidemiological surveillance. The sensitivity of this duplex real-time RT-PCR assay was 0.02 TCID50 (50% tissue culture infective dose) for H5N1 and 0.2 TCID50 for the pandemic H1N1, which was the same as that of each single-target RT-PCR for pandemic H1N1 and even more sensitive for H5N1 with the same primers and probes. No cross reactivity of detecting other subtype influenza viruses or respiratory tract viruses was observed. Two hundred and thirty-six clinical specimens were tested by comparing with single real-time RT-PCR and result from the duplex assay was 100% consistent with the results of single real-time RT-PCR and sequence analysis.

Coexistence of Avian Influenza Virus H10 and H9 Subtypes among Chickens in Live Poultry Markets during an Outbreak of Infection with a Novel H10N8 Virus in Humans in Nanchang, China.

PubMed

Hu, Maohong; Li, Xiaodan; Ni, Xiansheng; Wu, Jingwen; Gao, Rongbao; Xia, Wen; Wang, Dayan; He, Fenglan; Chen, Shengen; Liu, Yangqing; Guo, Shuangli; Li, Hui; Shu, Yuelong; Bethel, Jeffrey W; Liu, Mingbin; Moore, Justin B; Chen, Haiying

2015-01-01

Infection with the novel H10N8 virus in humans has raised concerns about its pandemic potential worldwide. We report the results of a cross-sectional study of avian influenza viruses (AIVs) in live poultry markets (LPMs) in Nanchang, China, after the first human case of H10N8 virus infection was reported in the city. A total of 201 specimens tested positive for AIVs among 618 samples collected from 24 LPMs in Nanchang from December 2013 to January 2014. We found that the LPMs were heavily contaminated by AIVs, with H9, H10, and H5 being the predominant subtypes and more than half of the LPMs providing samples that were positive for the H10 subtype. Moreover, the coexistence of different subtypes was common in LPMs. Of the 201 positive samples, 20.9% (42/201) had mixed infections with AIVs of different HA subtypes. Of the 42 mixed infections, 50% (21/42) showed the coexistence of the H9 and H10 subtypes, with or without H5, and were from chicken samples. This indicated that the H10N8 virus probably originated from segment reassortment of the H9 and H10 subtypes.

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.

Universal Detection and Identification of Avian Influenza Virus by Use of Resequencing Microarrays▿ †

PubMed Central

Lin, Baochuan; Malanoski, Anthony P.; Wang, Zheng; Blaney, Kate M.; Long, Nina C.; Meador, Carolyn E.; Metzgar, David; Myers, Christopher A.; Yingst, Samuel L.; Monteville, Marshall R.; Saad, Magdi D.; Schnur, Joel M.; Tibbetts, Clark; Stenger, David A.

2009-01-01

Zoonotic microbes have historically been, and continue to emerge as, threats to human health. The recent outbreaks of highly pathogenic avian influenza virus in bird populations and the appearance of some human infections have increased the concern of a possible new influenza pandemic, which highlights the need for broad-spectrum detection methods for rapidly identifying the spread or outbreak of all variants of avian influenza virus. In this study, we demonstrate that high-density resequencing pathogen microarrays (RPM) can be such a tool. The results from 37 influenza virus isolates show that the RPM platform is an effective means for detecting and subtyping influenza virus, while simultaneously providing sequence information for strain resolution, pathogenicity, and drug resistance without additional analysis. This study establishes that the RPM platform is a broad-spectrum pathogen detection and surveillance tool for monitoring the circulation of prevalent influenza viruses in the poultry industry and in wild birds or incidental exposures and infections in humans. PMID:19279171

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.

Prevalence of Multiple Subtypes of Avian Influenza Virus Antibodies in Egg Yolks of Mallard ( Anas platyrhynchos) and White-winged Terns ( Chlidonias leucopterus) in the Northeastern Republic of China.

PubMed

Chen, Xuelong; Qi, Yanping; Wang, Honghai; Wang, Yafei; Wang, Haixia; Ni, Hongbo

2018-06-12

Wild birds are natural hosts of avian influenza viruses (AIV) and can transmit viruses to poultry and other species. To monitor the prevalence of AIV antibodies, 211 eggs from wild Mallards ( Anas platyrhynchos) and 177 from wild White-winged Terns ( Chlidonias leucopterus) were collected from Zhalong Wetland and Xianghai Wetland in northeastern Republic of China from April to September, 2016. A hemagglutinin inhibition test detected the presence of H1, H3, H5, and H7 subtype-specific antibodies. The prevalences of AIV antibodies of subtypes H1 and H3 were relatively high while the prevalences of H5 and H7 AIV subtype antibody were low. In Zhalong Wetland, the prevalence of H1 AIV subtype antibody in Mallards was the highest, with a percentage of 11.0%. Prevalence of all AIV subtype-specific antibodies in Mallard was higher than those in White-winged Terns.

Influenza Research Database: An integrated bioinformatics resource for influenza virus research.

PubMed

Zhang, Yun; Aevermann, Brian D; Anderson, Tavis K; Burke, David F; Dauphin, Gwenaelle; Gu, Zhiping; He, Sherry; Kumar, Sanjeev; Larsen, Christopher N; Lee, Alexandra J; Li, Xiaomei; Macken, Catherine; Mahaffey, Colin; Pickett, Brett E; Reardon, Brian; Smith, Thomas; Stewart, Lucy; Suloway, Christian; Sun, Guangyu; Tong, Lei; Vincent, Amy L; Walters, Bryan; Zaremba, Sam; Zhao, Hongtao; Zhou, Liwei; Zmasek, Christian; Klem, Edward B; Scheuermann, Richard H

2017-01-04

The Influenza Research Database (IRD) is a U.S. National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Bioinformatics Resource Center dedicated to providing bioinformatics support for influenza virus research. IRD facilitates the research and development of vaccines, diagnostics and therapeutics against influenza virus by providing a comprehensive collection of influenza-related data integrated from various sources, a growing suite of analysis and visualization tools for data mining and hypothesis generation, personal workbench spaces for data storage and sharing, and active user community support. Here, we describe the recent improvements in IRD including the use of cloud and high performance computing resources, analysis and visualization of user-provided sequence data with associated metadata, predictions of novel variant proteins, annotations of phenotype-associated sequence markers and their predicted phenotypic effects, hemagglutinin (HA) clade classifications, an automated tool for HA subtype numbering conversion, linkouts to disease event data and the addition of host factor and antiviral drug components. All data and tools are freely available without restriction from the IRD website at https://www.fludb.org. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Effects of previous episodes of influenza and vaccination in preventing laboratory-confirmed influenza in Navarre, Spain, 2013/14 season.

PubMed

Castilla, Jesús; Navascués, Ana; Fernández-Alonso, Mirian; Reina, Gabriel; Albéniz, Esther; Pozo, Francisco; Álvarez, Nerea; Martínez-Baz, Iván; Guevara, Marcela; García-Cenoz, Manuel; Irisarri, Fátima; Casado, Itziar; Ezpeleta, Carmen

2016-06-02

We estimated whether previous episodes of influenza and trivalent influenza vaccination prevented laboratory-confirmed influenza in Navarre, Spain, in season 2013/14. Patients with medically-attended influenza-like illness (MA-ILI) in hospitals (n = 645) and primary healthcare (n = 525) were included. We compared 589 influenza cases and 581 negative controls. MA-ILI related to a specific virus subtype in the previous five seasons was defined as a laboratory-confirmed influenza infection with the same virus subtype or MA-ILI during weeks when more than 25% of swabs were positive for this subtype. Persons with previous MA-ILI had 30% (95% confidence interval (CI): -7 to 54) lower risk of MA-ILI, and those with previous MA-ILI related to A(H1N1)pdm09 or A(H3N2) virus, had a, respectively, 63% (95% CI: 16-84) and 65% (95% CI: 13-86) lower risk of new laboratory-confirmed influenza by the same subtype. Overall adjusted vaccine effectiveness in preventing laboratory-confirmed influenza was 31% (95% CI: 5-50): 45% (95% CI: 12-65) for A(H1N1)pdm09 and 20% (95% CI: -16 to 44) for A(H3N2). While a previous influenza episode induced high protection only against the same virus subtype, influenza vaccination provided low to moderate protection against all circulating subtypes. Influenza vaccine remains the main preventive option for high-risk populations.

An influenza A virus agglutination test using antibody-like polymers.

PubMed

Sukjee, Wannisa; Thitithanyanont, Arunee; Wiboon-Ut, Suwimon; Lieberzeit, Peter A; Paul Gleeson, M; Navakul, Krongkaew; Sangma, Chak

2017-10-01

Antibodies are commonly used in diagnostic routines to identify pathogens. The testing protocols are relatively simple, requiring a certain amount of a specific antibody to detect its corresponding pathogen. Antibody functionality can be mimicked by synthesizing molecularly imprinted polymers (MIPs), i.e. polymers that can selectively recognize a given template structure. Thus, MIPs are sometimes termed 'plastic antibody (PA)'. In this study, we have synthesized new granular MIPs using influenza A virus templates by precipitation polymerization. The selective binding of influenza A to the MIP particles was assessed and subsequently contrasted with other viruses. The affinities of influenza A virus towards the MIP was estimated based on an agglutination test by measuring the amount of influenza subtypes absorbed onto the MIPs. The MIPs produced using the H1N1 template showed specific reactivity to H1N1 while those produced using H5N1 and H3N2 templates showed cross-reactivity.

Enzootic genotype S of H9N2 avian influenza viruses donates internal genes to emerging zoonotic influenza viruses in China.

PubMed

Gu, Min; Chen, Hongzhi; Li, Qunhui; Huang, Junqing; Zhao, Mingjun; Gu, Xiaobing; Jiang, Kaijun; Wang, Xiaoquan; Peng, Daxin; Liu, Xiufan

2014-12-05

Avian influenza viruses of subtype H9N2 are widely prevalent in poultry in many Asian countries, and the segmented nature of the viral genome results in multiple distinct genotypes via reassortment. In this study, genetic evolution of H9N2 viruses circulating in eastern China during 2007-2013 was analyzed. The results showed that the diversity of the gene constellations generated six distinct genotypes, in which a novel genotype (S) bearing the backbone of A/chicken/Shanghai/F/98-like viruses by acquiring A/quail/Hong Kong/G1/97-like polymerase basic subunit 2 and matrix genes has gradually established its ecological niche and been consistently prevalent in chicken flocks in eastern China since its first detection in 2007. Furthermore, genotype S possessed the peculiarity to donate most of its gene segments to other emerging influenza A viruses in China, including the novel reassortant highly pathogenic avian influenza H5N2, the 2013 novel H7N7, H7N9 and the latest reassortant H10N8 viruses, with potential threat to poultry industry and human health. Copyright © 2014 Elsevier B.V. All rights reserved.

Susceptibility of wild passerines to subtype H5N1 highly pathogenic avian influenza viruses.

PubMed

Fujimoto, Yoshikazu; Usui, Tatsufumi; Ito, Hiroshi; Ono, Etsuro; Ito, Toshihiro

2015-01-01

Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype have spread throughout many areas of Asia, Europe and Africa, and numerous cases of HPAI outbreaks in domestic and wild birds have been reported. Although recent studies suggest that the dissemination of H5N1 viruses is closely linked to the migration of wild birds, information on the potential for viral infection in species other than poultry and waterfowl is relatively limited. To investigate the susceptibility of terrestrial wild birds to infection with H5N1 HPAI viruses, common reed buntings (Emberiza schoeniclus), pale thrushes (Turdus pallidus) and brown-eared bulbuls (Hypsipetes amaurotis) were infected with A/mountain hawk-eagle/Kumamoto/1/07(H5N1) and A/whooper swan/Aomori/1/08(H5N1). The results showed that common reed buntings and brown-eared bulbuls were severely affected by both virus strains (100% mortality). While pale thrushes did not exhibit any clinical signs, seroconversion was confirmed. In common reed buntings, intraspecies-transmission of A/whooper swan/Aomori/1/08 to contact birds was also confirmed. The findings show that three passerine species; common reed buntings, brown-eared bulbuls and pale thrushes are susceptible to infection by H5N1 HPAI viruses, which emphasizes that continued surveillance of species other than waterfowl is crucial for effective monitoring of H5N1 HPAI virus outbreaks.

Mechanisms of Cross-protection by Influenza Virus M2-based Vaccines.

PubMed

Lee, Yu-Na; Kim, Min-Chul; Lee, Young-Tae; Kim, Yu-Jin; Kang, Sang-Moo

2015-10-01

Current influenza virus vaccines are based on strain-specific surface glycoprotein hemagglutinin (HA) antigens and effective only when the predicted vaccine strains and circulating viruses are well-matched. The current strategy of influenza vaccination does not prevent the pandemic outbreaks and protection efficacy is reduced or ineffective if mutant strains emerge. It is of high priority to develop effective vaccines and vaccination strategies conferring a broad range of cross protection. The extracellular domain of M2 (M2e) is highly conserved among human influenza A viruses and has been utilized to develop new vaccines inducing cross protection against different subtypes of influenza A virus. However, immune mechanisms of cross protection by M2e-based vaccines still remain to be fully elucidated. Here, we review immune correlates and mechanisms conferring cross protection by M2e-based vaccines. Molecular and cellular immune components that are known to be involved in M2 immune-mediated protection include antibodies, B cells, T cells, alveolar macrophages, Fc receptors, complements, and natural killer cells. Better understanding of protective mechanisms by immune responses induced by M2e vaccination will help facilitate development of broadly cross protective vaccines against influenza A virus.

Avian Influenza (Bird Flu)

MedlinePlus

... Spread Bird Flu to People Interim Guidance on Testing Pandemic Flu Key Information Prevention & Treatment Influenza A Type Viruses & Subtypes Transmission of Avian Influenza A Viruses Between Animals and People Related Links Research Glossary of Influenza ( ...

Investigation of avian influenza virus in poultry and wild birds due to novel avian-origin influenza A(H10N8) in Nanchang City, China.

PubMed

Ni, Xiansheng; He, Fenglan; Hu, Maohong; Zhou, Xianfeng; Wang, Bin; Feng, Changhua; Wu, Yumei; Li, Youxing; Tu, Junling; Li, Hui; Liu, Mingbin; Chen, Haiying; Chen, Shengen

2015-01-01

Multiple reassortment events within poultry and wild birds had resulted in the establishment of another novel avian influenza A(H10N8) virus, and finally resulted in human death in Nanchang, China. However, there was a paucity of information on the prevalence of avian influenza virus in poultry and wild birds in Nanchang area. We investigated avian influenza virus in poultry and wild birds from live poultry markets, poultry countyards, delivery vehicles, and wild-bird habitats in Nanchang. We analyzed 1036 samples from wild birds and domestic poultry collected from December 2013 to February 2014. Original biological samples were tested for the presence of avian influenza virus using specific primer and probe sets of H5, H7, H9, H10 and N8 subtypes by real-time RT-PCR. In our analysis, the majority (97.98%) of positive samples were from live poultry markets. Among the poultry samples from chickens and ducks, AIV prevalence was 26.05 and 30.81%, respectively. Mixed infection of different HA subtypes was very common. Additionally, H10 subtypes coexistence with N8 was the most prevalent agent during the emergence of H10N8. This event illustrated a long-term surveillance was so helpful for pandemic preparedness and response. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

The significance of avian influenza virus mouse-adaptation and its application in characterizing the efficacy of new vaccines and therapeutic agents

PubMed Central

2017-01-01

Due to the increased frequency of interspecies transmission of avian influenza viruses, studies designed to identify the molecular determinants that could lead to an expansion of the host range have been increased. A variety of mouse-based mammalian-adaptation studies of avian influenza viruses have provided insight into the genetic alterations of various avian influenza subtypes that may contribute to the generation of a pandemic virus. To date, the studies have focused on avian influenza subtypes H5, H6, H7, H9, and H10 which have recently caused human infection. Although mice cannot fully reflect the course of human infection with avian influenza, these mouse studies can be a useful method for investigating potential mammalian adaptive markers against newly emerging avian influenza viruses. In addition, due to the lack of appropriate vaccines against the diverse emerging influenza viruses, the generation of mouse-adapted lethal variants could contribute to the development of effective vaccines or therapeutic agents. Within this review, we will summarize studies that have demonstrated adaptations of avian influenza viruses that result in an altered pathogenicity in mice which may suggest the potential application of mouse-lethal strains in the development of influenza vaccines and/or therapeutics in preclinical studies. PMID:28775972

Vaccination with Newcastle disease virus vectored vaccine protects chickens against highly pathogenic H7 avian influenza virus.

PubMed

Schröer, Diana; Veits, Jutta; Grund, Christian; Dauber, Malte; Keil, Günther; Granzow, Harald; Mettenleiter, Thomas C; Römer-Oberdörfer, Angela

2009-06-01

A recombinant Newcastle disease virus (NDV) was engineered to express the hemagglutinin (HA) gene of avian influenza virus (AIV) subtype H7. The HA gene was inserted between the genes encoding NDV fusion and hemagglutinin-neuraminidase proteins. Within the H7 open reading frame, an NDV gene end-like sequence was eliminated by silent mutation. The expression of H7 protein was detected by western blot analysis and indirect immunofluorescence. The existence of H7 protein in the envelope of recombinant Newcastle disease virions was shown by immunoelectron microscopy. The protective efficacy of recombinant NDVH7m against virulent NDV, as well as against highly pathogenic avian influenza virus (HPAIV), was evaluated in specific-pathogen-free chickens. After a single immunization, all chickens developed NDV-specific, as well as AIV H7-specific, antibodies and were completely protected from clinical disease after infection with a lethal dose of virulent NDV or the homologous H7N1 HPAIV, while all control animals died within four days. Shedding of AIV challenge virus was strongly reduced compared to nonvaccinated control birds. Furthermore, the immunized birds developed antibodies against the AIV nucleoprotein after challenge infection. Thus, NDVH7m could be used as a marker vaccine against subtype H7 avian influenza.

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

PubMed Central

2011-01-01

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

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

PubMed

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

2009-08-06

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

Virus-like particles comprising H5, H7 and H9 hemagglutinins elicit protective immunity to heterologous avian influenza viruses in chickens

USDA-ARS?s Scientific Manuscript database

Avian influenza (AI) viruses circulating in wild birds pose a serious threat to public health. Human and veterinary vaccines against AI subtypes are needed. Here we prepared triple-subtype VLPs that co-localized H5, H7 and H9 antigens derived from H5N1, H7N3 and H9N2 viruses. VLPs also contained inf...

Unique Structural Features of Influenza Virus H15 Hemagglutinin

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

Tzarum, Netanel; McBride, Ryan; Nycholat, Corwin M.

Influenza A H15 viruses are members of a subgroup (H7-H10-H15) of group 2 hemagglutinin (HA) subtypes that include H7N9 and H10N8 viruses that were isolated from humans during 2013. The isolation of avian H15 viruses is, however, quite rare and, until recently, geographically restricted to wild shorebirds and waterfowl in Australia. The HAs of H15 viruses contain an insertion in the 150-loop (loop beginning at position 150) of the receptor-binding site common to this subgroup and a unique insertion in the 260-loop compared to any other subtype. Here, we show that the H15 HA has a high preference for avianmore » receptor analogs by glycan array analyses. The H15 HA crystal structure reveals that it is structurally closest to H7N9 HA, but the head domain of the H15 trimer is wider than all other HAs due to a tilt and opening of the HA1 subunits of the head domain. The extended 150-loop of the H15 HA retains the conserved conformation as in H7 and H10 HAs. Furthermore, the elongated 260-loop increases the exposed HA surface and can contribute to antigenic variation in H15 HAs. Since avian-origin H15 HA viruses have been shown to cause enhanced disease in mammalian models, further characterization and immune surveillance of H15 viruses are warranted. IMPORTANCEIn the last 2 decades, an apparent increase has been reported for cases of human infection by emerging avian influenza A virus subtypes, including H7N9 and H10N8 viruses isolated during 2013. H15 is the other member of the subgroup of influenza A virus group 2 hemagglutinins (HAs) that also include H7 and H10. H15 viruses have been restricted to Australia, but recent isolation of H15 viruses in western Siberia suggests that they could be spread more globally via the avian flyways that converge and emanate from this region. Here we report on characterization of the three-dimensional structure and receptor specificity of the H15 hemagglutinin, revealing distinct features and specificities that can aid in global

Cloned Defective Interfering Influenza Virus Protects Ferrets from Pandemic 2009 Influenza A Virus and Allows Protective Immunity to Be Established

PubMed Central

Dimmock, Nigel J.; Taylor, Irene; Cheung, Linda; Hallis, Bassam; Marriott, Anthony C.; Carroll, Miles W.; Easton, Andrew J.

2012-01-01

Influenza A viruses are a major cause of morbidity and mortality in the human population, causing epidemics in the winter, and occasional worldwide pandemics. In addition there are periodic outbreaks in domestic poultry, horses, pigs, dogs, and cats. Infections of domestic birds can be fatal for the birds and their human contacts. Control in man operates through vaccines and antivirals, but both have their limitations. In the search for an alternative treatment we have focussed on defective interfering (DI) influenza A virus. Such a DI virus is superficially indistinguishable from a normal virus but has a large deletion in one of the eight RNAs that make up the viral genome. Antiviral activity resides in the deleted RNA. We have cloned one such highly active DI RNA derived from segment 1 (244 DI virus) and shown earlier that intranasal administration protects mice from lethal disease caused by a number of different influenza A viruses. A more cogent model of human influenza is the ferret. Here we found that intranasal treatment with a single dose of 2 or 0.2 µg 244 RNA delivered as A/PR/8/34 virus particles protected ferrets from disease caused by pandemic virus A/California/04/09 (A/Cal; H1N1). Specifically, 244 DI virus significantly reduced fever, weight loss, respiratory symptoms, and infectious load. 244 DI RNA, the active principle, was amplified in nasal washes following infection with A/Cal, consistent with its amelioration of clinical disease. Animals that were treated with 244 DI RNA cleared infectious and DI viruses without delay. Despite the attenuation of infection and disease by DI virus, ferrets formed high levels of A/Cal-specific serum haemagglutination-inhibiting antibodies and were solidly immune to rechallenge with A/Cal. Together with earlier data from mouse studies, we conclude that 244 DI virus is a highly effective antiviral with activity potentially against all influenza A subtypes. PMID:23251341

Influenza A virus transmission via respiratory aerosols or droplets as it relates to pandemic potential

PubMed Central

Richard, Mathilde; Fouchier, Ron A.M.

2015-01-01

Many respiratory viruses of humans originate from animals. For instance, there are now eight paramyxoviruses, four coronaviruses and four orthomxoviruses that cause recurrent epidemics in humans but were once confined to other hosts. In the last decade, several members of the same virus families have jumped the species barrier from animals to humans. Fortunately, these viruses have not become established in humans, because they lacked the ability of sustained transmission between humans. However, these outbreaks highlighted the lack of understanding of what makes a virus transmissible. In part triggered by the relatively high frequency of occurrence of influenza A virus zoonoses and pandemics, the influenza research community has started to investigate the viral genetic and biological traits that drive virus transmission via aerosols or respiratory droplets between mammals. Here we summarize recent discoveries on the genetic and phenotypic traits required for airborne transmission of zoonotic influenza viruses of subtypes H5, H7 and H9 and pandemic viruses of subtypes H1, H2 and H3. Increased understanding of the determinants and mechanisms of respiratory virus transmission is not only key from a basic scientific perspective, but may also aid in assessing the risks posed by zoonotic viruses to human health, and preparedness for such risks. PMID:26385895

A Historical Perspective of Influenza A(H1N2) Virus

PubMed Central

McVernon, Jodie; Hall, Robert; Leder, Karin

2014-01-01

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

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.

Possible interference between seasonal epidemics of influenza and other respiratory viruses in Hong Kong, 2014-2017.

PubMed

Zheng, Xueying; Song, Zhengyu; Li, Yapeng; Zhang, Juanjuan; Wang, Xi-Ling

2017-12-16

Unlike influenza viruses, little is known about the prevalence and seasonality of other respiratory viruses because laboratory surveillance for non-influenza respiratory viruses is not well developed or supported in China and other resource-limited countries. We studied the interference between seasonal epidemics of influenza viruses and five other common viruses that cause respiratory illnesses in Hong Kong from 2014 to 2017. The weekly laboratory-confirmed positive rates of each virus were analyzed from 2014 to 2017 in Hong Kong to describe the epidemiological trends and interference between influenza viruses, respiratory syncytial virus (RSV), parainfluenza virus (PIV), adenovirus, enterovirus and rhinovirus. A sinusoidal model was established to estimate the peak timing of each virus by phase angle parameters. Seasonal features of the influenza viruses, PIV, enterovirus and adenovirus were obvious, whereas annual peaks of RSV and rhinovirus were not observed. The incidence of the influenza viruses usually peaked in February and July, and the summer peaks in July were generally caused by the H3 subtype of influenza A alone. When influenza viruses were active, other viruses tended to have a low level of activity. The peaks of the influenza viruses were not synchronized. An epidemic of rhinovirus tended to shift the subsequent epidemics of the other viruses. The evidence from recent surveillance data in Hong Kong suggests that viral interference during the epidemics of influenza viruses and other common respiratory viruses might affect the timing and duration of subsequent epidemics of a certain or several viruses.

[Influenza virus epidemiology and ecology, with special reference to bird species associated with water. Literature review and observations].

PubMed

van Tongeren, H A; Voous, K H

1987-12-01

Only a limited number of A-subtypes of influenza virus so far caused disease in human subjects, pigs and horses; this occurred in more or less defined areas which occasionally showed epidemic aggravations, becoming apparent as rapidly spreading epidemics or otherwise in even the form of pandemics. However this number of antigenic subtypes was found to be fairly constant and host-specific. Earlier studies were done in domesticated fowl and birds, though particularly in water birds in recent years, and numerous subtypes were detected, only a small number of these subtypes also being found to occur in man, pigs and horses. It became increasingly apparent that particularly mallards, but also other water birds play an extremely important role in the maintenance as well as in the distribution and circulation of these orthomyxoviruses in nature. These infections in water birds were not merely caused by a single subtype but occasionally by two or more antigenically different subtypes. This could be conducive to the appearance of recombinants as a result of genetic rearrangement in the cells lining the alimentary tracts of birds. Occasionally, subtypes observed in man were also found to occur in birds, which gave rise to the question of the extent to which birds are the origin or sources of infections of human epidemics caused by these subtypes. This also holds good for the subtypes in pigs. In addition to a number of oecological and ornithological considerations, reference was also made to systematic facts and routes along which further investigations on the presence of influenza viruses in the world of birds could be taken up, particular attention being paid to migratory birds. As birds of passage pass over and find their way into isolated areas as well as human population centres, these birds play a role which is yet unknown both in the distribution and in the overwintering of influenza viruses. Conditions in which wild and domesticated (water) birds, pigs, horses and

(Highly pathogenic) avian influenza as a zoonotic agent.

PubMed

Kalthoff, Donata; Globig, Anja; Beer, Martin

2010-01-27

Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential. Copyright 2009 Elsevier B.V. All rights reserved.

Issues encountered in development of enzyme-linked immunosorbent assay for use in detecting Influenza A virus subtype H5N1 exposure in swine.

PubMed

Buehler, Jason; Lager, Kelly; Vincent, Amy; Miller, Cathy; Thacker, Eileen; Janke, Bruce

2014-03-01

A potential mechanism by which highly pathogenic avian Influenza A virus subtype H5N1 could more readily infect human beings is through the infection of and adaptation in pigs. To detect the occurrence of such infection, monitoring of pig populations through serological screening would be highly desirable. In the current study, hemagglutination inhibition assays were able to detect antibodies against H5N1 developed in pigs, but because of antigenic variation between clades, the use of multiple virus strains were required. Whole recombinant virus and recombinant hemagglutinin antigen enzyme-linked immunosorbent assays (ELISAs) were generated that could detect antibody against multiple H5N1 strains, but which also detected antibody against endemic swine influenza viruses. A recombinant hemagglutinin antigen-based ELISA was as effective as the whole virus antigen ELISAs in detecting antibody against the H5N1 virus strains used and eliminated nearly all of the cross-reactivity with non-H5N1 virus antibody. The current study also highlighted the difficulty in establishing a decision (cutoff) value that would effectively counterbalance nonspecific reactivity against sensitivity. The results provide important information and considerations for the development of serological screening assays for highly pathogenic avian H5N1 viruses.

Evolutionary Dynamics and Global Diversity of Influenza A Virus.

PubMed

Rejmanek, Daniel; Hosseini, Parviez R; Mazet, Jonna A K; Daszak, Peter; Goldstein, Tracey

2015-11-01

The increasing number of zoonotic infections caused by influenza A virus (IAV) subtypes of avian origin (e.g., H5N1 and H7N9) in recent years underscores the need to better understand the factors driving IAV evolution and diversity. To evaluate the current feasibility of global analyses to contribute to this aim, we evaluated information in the public domain to explore IAV evolutionary dynamics, including nucleotide substitution rates and selection pressures, using 14 IAV subtypes in 32 different countries over a 12-year period (2000 to 2011). Using geospatial information from 39,785 IAV strains, we examined associations between subtype diversity and socioeconomic, biodiversity, and agricultural indices. Our analyses showed that nucleotide substitution rates for 11 of the 14 evaluated subtypes tended to be higher in Asian countries, particularly in East Asia, than in Canada and the United States. Similarly, at a regional level, subtypes H5N1, H5N2, and H6N2 exhibited significantly higher substitution rates in East Asia than in North America. In contrast, the selection pressures (measured as ratios of nonsynonymous to synonymous evolutionary changes [dN/dS ratios]) acting on individual subtypes showed little geographic variation. We found that the strongest predictors for the detected subtype diversity at the country level were reporting effort (i.e., total number of strains reported) and health care spending (an indicator of economic development). Our analyses also identified major global gaps in IAV reporting (including a lack of sequences submitted from large portions of Africa and South America and a lack of geolocation information) and in broad subtype testing which, until addressed, will continue to hinder efforts to track the evolution and diversity of IAV around the world. In recent years, an increasing number of influenza A virus (IAV) subtypes, including H5N1, H7N9, and H10N8, have been detected in humans. High fatality rates have led to an increased

Antigenic characterization of H3 subtypes of avian influenza A viruses from North America

USGS Publications Warehouse

Bailey, Elizabeth; Long, Li-Pong; Zhao, Nan; Hall, Jeffrey S.; Baroch, John A; Nolting, Jaqueline; Senter, Lucy; Cunningham, Frederick L; Pharr, G Todd; Hanson, Larry; Slemons, Richard; DeLiberto, Thomas J.; Wan, Xiu-Feng

2016-01-01

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America.

PubMed

Bailey, Elizabeth; Long, Li-Ping; Zhao, Nan; Hall, Jeffrey S; Baroch, John A; Nolting, Jacqueline; Senter, Lucy; Cunningham, Frederick L; Pharr, G Todd; Hanson, Larry; Slemons, Richard; DeLiberto, Thomas J; Wan, Xiu-Feng

2016-05-01

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

Avian influenza virus

USDA-ARS?s Scientific Manuscript database

Avian influenza virus (AIV) is type A influenza, which is adapted to an avian host. Although avian influenza has been isolated from numerous avian species, the primary natural hosts for the virus are dabbling ducks, shorebirds, and gulls. The virus can be found world-wide in these species and in o...

Evolution of canine and equine influenza (H3N8) viruses co-circulating between 2005 and 2008

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

Rivailler, Pierre; Perry, Ijeoma A.; Jang Yunho

Influenza virus, subtype H3N8, was transmitted from horses to greyhound dogs in 2004 and subsequently spread to pet dog populations. The co-circulation of H3N8 viruses in dogs and horses makes bi-directional virus transmission between these animal species possible. To understand the dynamics of viral transmission, we performed virologic surveillance in dogs and horses between 2005 and 2008 in the United States. The genomes of influenza A H3N8 viruses isolated from 36 dogs and horses were sequenced to determine their origin and evolution. Phylogenetic analyses revealed that H3N8 influenza viruses from horses and dogs were monophyletic and distinct. There was nomore » evidence of canine influenza virus infection in horses with respiratory disease or new introductions of equine influenza viruses into dogs in the United States. Analysis of a limited number of equine influenza viruses suggested substantial separation in the transmission of viruses causing clinically apparent influenza in dogs and horses.« less

Serological surveillance reveals widespread influenza A H7 and H9 subtypes among chicken flocks in Egypt.

PubMed

Afifi, Manal A A; El-Kady, Magdy F; Zoelfakar, Sahar A; Abdel-Moneim, Ahmed Sayed; Abddel-Moneim, Ahmed Sayed

2013-02-01

Multiple avian influenza viruses' subtypes are circulating worldwide possessing serious threat to human populations and considered key contributors to the emergence of human influenza pandemics. This study aimed to identify the potential existence of H7 and H9 avian influenza infections circulating among chicken flocks in Egypt. Serum samples were collected from chicken flocks that experienced respiratory distresses and/or variable mortality rates. H7 and H9 virus infections were screened by haemagglutination inhibition assay using chicken erythrocytes. Serum samples were collected from 9 broiler, 12 breeder and 18 layer flocks. Out of 1,225 examined sera, 417 (34 %) from 14 flocks and 605 (49.4 %) from 21 flocks were found positive for H7 and H9, respectively. Prevalence of both H7 and H9 antibodies were higher in layer followed by breeder then broiler flocks. Special consideration should be paid to control influenza viruses in Egypt, as pandemic influenza strains may develop unnoticed given the presence of subclinical infections, and the possibility of re-assortment with the prevailing endemic H5N1 virus strains in Egypt do exist.

Clinical accuracy of a PLEX-ID flu device for simultaneous detection and identification of influenza viruses A and B.

PubMed

Tang, Yi-Wei; Lowery, Kristin S; Valsamakis, Alexandra; Schaefer, Virginia C; Chappell, James D; White-Abell, Jill; Quinn, Criziel D; Li, Haijing; Washington, Cicely A; Cromwell, Jenna; Giamanco, Chantel M; Forman, Michael; Holden, Jeffery; Rothman, Richard E; Parker, Michelle L; Ortenberg, Elaine V; Zhang, Lei; Lin, Yea-Lin; Gaydos, Charlotte A

2013-01-01

Respiratory tract infections caused by influenza A and B viruses often present nonspecifically, and a rapid, high-throughput laboratory technique that can identify influenza viruses is clinically and epidemiologically desirable. The PLEX-ID Flu assay (Abbott Molecular Inc., Des Plaines, IL) incorporates multilocus PCR and electrospray ionization-mass spectrometry to detect and differentiate influenza A 2009 H1N1 (H1N1-p), seasonal H1N1 (H1N1-s), influenza A H3N2, and influenza B viruses in nasopharyngeal swab (NPS) specimens. The clinical performance characteristics of the PLEX-ID Flu assay in symptomatic patients were determined in this multicenter trial. A total of 2,617 prospectively and retrospectively collected NPS specimens from patients with influenza-like illness between February 2008 and 28 May 2010 were eligible for inclusion in the study. Each specimen was tested in parallel by the PLEX-ID Flu assay and by the Prodesse ProFLU+ assay (Prodesse Inc., Madison, WI), to detect influenza A and B viruses. Specimens testing positive for influenza A virus by ProFLU+ were subtyped as H1N1-p, H1N1-s, or H3N2 by using the ProFAST+ assay (Gen-Probe Prodesse Inc.). The reproducibility of the PLEX-ID Flu assay ranged from 98.3 to 100.0%, as determined by testing a nine-specimen panel at three clinical sites on each of 5 days. Positive percent agreements (PPAs) and negative percent agreements (NPAs) of the PLEX-ID Flu assay were 94.5% and 99.0% for influenza A virus and 96.0% and 99.9% for influenza B virus, respectively. For the influenza A virus subtyping characterization, the PLEX-ID Flu assay had PPAs and NPAs of 98.3% and 97.5% for H1N1-p, 88.6% and 100.0% for H1N1-s, and 98.0% and 99.9% for H3N2, respectively. The overall agreements between the PLEX-ID and Prodesse ProFLU+/ProFAST+ assays were 97.1 to 100.0%. Bidirectional Sanger sequencing analysis revealed that 87.5% of 96 discrepant results between the PLEX-ID Flu and ProFLU+/ProFAST+ assays were found upon

Phylogenetic Analysis of H6 Influenza Viruses Isolated from Rosy-Billed Pochards (Netta peposaca) in Argentina Reveals the Presence of Different HA Gene Clusters ▿

PubMed Central

Rimondi, Agustina; Xu, Kemin; Craig, Maria Isabel; Shao, Hongxia; Ferreyra, Hebe; Rago, Maria Virginia; Romano, Marcelo; Uhart, Marcela; Sutton, Troy; Ferrero, Andrea; Perez, Daniel R.; Pereda, Ariel

2011-01-01

Until recently, influenza A viruses from wild waterfowl in South America were rarely isolated and/or characterized. To explore the ecology of influenza A viruses in this region, a long-term surveillance program was established in 2006 for resident and migratory water birds in Argentina. We report the characterization of 5 avian influenza viruses of the H6 hemagglutinin (HA) subtype isolated from rosy-billed pochards (Netta peposaca). Three of these viruses were paired to an N2 NA subtype, while the other two were of the N8 subtype. Genetic and phylogenetic analyses of the internal gene segments revealed a close relationship with influenza viruses from South America, forming a unique clade and supporting the notion of independent evolution from influenza A viruses in other latitudes. The presence of NS alleles A and B was also identified. The HA and NA genes formed unique clades separate from North American and Eurasian viruses, with the exception of the HA gene of one isolate, which was more closely related to the North American lineage, suggesting possible interactions between viruses of North American and South American lineages. Animal studies suggested that these Argentine H6 viruses could replicate and transmit inefficiently in chickens, indicating limited adaptation to poultry. Our results highlight the importance of continued influenza virus surveillance in wild birds of South America, especially considering the unique evolution of these viruses. PMID:21976652

Highly Pathogenic Avian Influenza Virus (H5N1) Outbreak in Captive Wild Birds and Cats, Cambodia

PubMed Central

Marx, Nick; Ong, Sivuth; Gaidet, Nicolas; Hunt, Matt; Manuguerra, Jean-Claude; Sorn, San; Peiris, Malik; Van der Werf, Sylvie; Reynes, Jean-Marc

2009-01-01

From December 2003 through January 2004, the Phnom Tamao Wildlife Rescue Centre, Cambodia, was affected by the highly pathogenic influenza virus (H5N1). Birds from 26 species died. Influenza virus subtype H5N1 was detected in 6 of 7 species tested. Cats from 5 of 7 species were probably infected; none died. PMID:19239769

A new class of synthetic anti-lipopolysaccharide peptides inhibits influenza A virus replication by blocking cellular attachment.

PubMed

Hoffmann, Julia; Schneider, Carola; Heinbockel, Lena; Brandenburg, Klaus; Reimer, Rudolph; Gabriel, Gülsah

2014-04-01

Influenza A viruses are a continuous threat to human health as illustrated by the 2009 H1N1 pandemic. Since circulating influenza virus strains become increasingly resistant against currently available drugs, the development of novel antivirals is urgently needed. Here, we have evaluated a recently described new class of broad-spectrum antiviral peptides (synthetic anti-lipopolysaccharide peptides; SALPs) for their potential to inhibit influenza virus replication in vitro and in vivo. We found that particularly SALP PEP 19-2.5 shows high binding affinities for the influenza virus receptor molecule, N-Acetylneuraminic acid, leading to impaired viral attachment and cellular entry. As a result, replication of several influenza virus subtypes (H7N7, H3N2 and 2009 pandemic H1N1) was strongly reduced. Furthermore, mice co-treated with PEP 19-2.5 were protected against an otherwise 100% lethal H7N7 influenza virus infection. These findings show that SALPs exhibit antiviral activity against influenza viruses by blocking virus attachment and entry into host cells. Thus, SALPs present a new class of broad-spectrum antiviral peptides for further development for influenza virus therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

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

African Green Monkeys Recapitulate the Clinical Experience with Replication of Live Attenuated Pandemic Influenza Virus Vaccine Candidates

PubMed Central

Matsuoka, Yumiko; Suguitan, Amorsolo; Orandle, Marlene; Paskel, Myeisha; Boonnak, Kobporn; Gardner, Donald J.; Feldmann, Friederike; Feldmann, Heinz; Marino, Michael; Jin, Hong; Kemble, George

2014-01-01

ABSTRACT Live attenuated cold-adapted (ca) H5N1, H7N3, H6N1, and H9N2 influenza vaccine viruses replicated in the respiratory tract of mice and ferrets, and 2 doses of vaccines were immunogenic and protected these animals from challenge infection with homologous and heterologous wild-type (wt) viruses of the corresponding subtypes. However, when these vaccine candidates were evaluated in phase I clinical trials, there were inconsistencies between the observations in animal models and in humans. The vaccine viruses did not replicate well and immune responses were variable in humans, even though the study subjects were seronegative with respect to the vaccine viruses before vaccination. Therefore, we sought a model that would better reflect the findings in humans and evaluated African green monkeys (AGMs) as a nonhuman primate model. The distribution of sialic acid (SA) receptors in the respiratory tract of AGMs was similar to that in humans. We evaluated the replication of wt and ca viruses of avian influenza (AI) virus subtypes H5N1, H6N1, H7N3, and H9N2 in the respiratory tract of AGMs. All of the wt viruses replicated efficiently, while replication of the ca vaccine viruses was restricted to the upper respiratory tract. Interestingly, the patterns and sites of virus replication differed among the different subtypes. We also evaluated the immunogenicity and protective efficacy of H5N1, H6N1, H7N3, and H9N2 ca vaccines. Protection from wt virus challenge correlated well with the level of serum neutralizing antibodies. Immune responses were slightly better when vaccine was delivered by both intranasal and intratracheal delivery than when it was delivered intranasally by sprayer. We conclude that live attenuated pandemic influenza virus vaccines replicate similarly in AGMs and human subjects and that AGMs may be a useful model to evaluate the replication of ca vaccine candidates. IMPORTANCE Ferrets and mice are commonly used for preclinical evaluation of influenza

Recognition of dual targets by a molecular beacon-based sensor: subtyping of influenza A virus.

PubMed

Lee, Chun-Ching; Liao, Yu-Chieh; Lai, Yu-Hsuan; Lee, Chang-Chun David; Chuang, Min-Chieh

2015-01-01

A molecular beacon (MB)-based sensor to offer a decisive answer in combination with information originated from dual-target inputs is designed. The system harnesses an assistant strand and thermodynamically favored designation of unpaired nucleotides (UNs) to process the binary targets in "AND-gate" format and report fluorescence in "off-on" mechanism via a formation of a DNA four-way junction (4WJ). By manipulating composition of the UNs, the dynamic fluorescence difference between the binary targets-coexisting circumstance and any other scenario was maximized. Characteristic equilibrium constant (K), change of entropy (ΔS), and association rate constant (k) between the association ("on") and dissociation ("off") states of the 4WJ were evaluated to understand unfolding behavior of MB in connection to its sensing capability. Favorable MB and UNs were furthermore designed toward analysis of genuine genetic sequences of hemagglutinin (HA) and neuraminidase (NA) in an influenza A H5N2 isolate. The MB-based sensor was demonstrated to yield a linear calibration range from 1.2 to 240 nM and detection limit of 120 pM. Furthermore, high-fidelity subtyping of influenza virus was implemented in a sample of unpurified amplicons. The strategy opens an alternative avenue of MB-based sensors for dual targets toward applications in clinical diagnosis.

[Burden of influenza virus type B and mismatch with the flu vaccine in Spain].

PubMed

Eiros-Bouza, Jose Ma; Pérez-Rubio, Alberto

2015-02-01

Since the 80s two lineages of type B viruses are co - circulating in the world. Antigenic differences between them are important and it leads to lack of cross-reactivity. The impact on the burden of disease due to influenza B virus, poor foresight in estimating which of the two lineages of B viruses circulate in the season, and the consequent lack of immunity in case of including the wrong strain make that the availability of the quadrivalent vaccine is very useful. The aim of this paper is to analyze the past influenza seasons in Spain to assess the burden of disease, divergence between the vaccine strain and the circulating B and viral characteristics associated with type B in each seasonal epidemic. Review of all reports issued by the Influenza Surveillance System in Spain since the 2003-2004 season to 2012-2013. Over the past influenza seasons, although type A was present mostly, circulation of influenza B virus in each season was observed, even being co - dominant in some of them. In a high number of seasons the divergence between the vaccine strain and the circulating strain lineage has been observed The protective effect of influenza vaccine has varied depending on the type / subtype of influenza virus studied. The vaccine effectiveness against influenza infection by influenza B virus has varied greatly depending on the season analyzed.

Co-circulation of paramyxo- and influenza viruses in pigeons in Egypt.

PubMed

Mansour, Shimaa M G; Mohamed, Fakry F; Eid, Amal A M; Mor, Sunil K; Goyal, Sagar M

2017-08-01

In recent years, avian influenza virus (AIV) and Newcastle disease virus (NDV) have caused large-scale outbreaks in many countries, including Egypt. The culling and vaccination strategies have failed to control both viruses in Egypt. In this study, we investigated the outbreaks of nervous manifestations and deaths in pigeons between 2013 and 2015. The H5N1 subtype of the highly pathogenic avian influenza virus and pigeon paramyxovirus-1, an antigenic variant of NDV, were found to be the cause; AIV and pigeon paramyxovirus-1 were isolated from 61.3% (19/31) and 67.8% (21/31) of tested pigeons, respectively. Co-infection with both viruses was detected in 51.6% of pigeons (16/31). The AIV sequences showed PQGEKRRKKR/GLF motif at the haemagglutinin gene cleavage site, which is typical of the highly pathogenic H5N1 subtype. The phylogenetic tree showed that the highly pathogenic avian influenza belonged to clade 2.2.1.2. The NDV sequences carried one of the three motifs, 112 GKQGRL 117 , 112 KRQKRF 117 or 112 RRQKRF 117 , at the fusion protein cleavage site and were classified as genotypes I, VI and II in NDV-class II, respectively. This indicated that different genotypes of NDV can circulate simultaneously among pigeons. Further analysis revealed the clustering of some sequences in sub-genotypes Ia and VIb.2. To the best of our knowledge, these sub-genotypes have not been previously reported from pigeons in Egypt. Our results should serve as a base for future studies on both viruses in Egypt.

Evaluation of twenty-two rapid antigen detection tests in the diagnosis of Equine Influenza caused by viruses of H3N8 subtype.

PubMed

Yamanaka, Takashi; Nemoto, Manabu; Bannai, Hiroshi; Tsujimura, Koji; Kondo, Takashi; Matsumura, Tomio; Gildea, Sarah; Cullinane, Ann

2016-03-01

Equine influenza (EI) is a highly contagious disease caused by viruses of the H3N8 subtype. The rapid diagnosis of EI is essential to reduce the disease spread. Many rapid antigen detection (RAD) tests for diagnosing human influenza are available, but their ability to diagnose EI has not been systematically evaluated. The aim of this study was to compare the performance of 22 RAD tests in the diagnosis of EI. The 22 RAD tests were performed on fivefold serial dilutions of EI virus to determine their detection limits. The four most sensitive RAD tests (ImmunoAce Flu, BD Flu examan, Quick chaser Flu A, B and ESPLINE Influenza A&B-N) were further evaluated using nasopharyngeal samples collected from experimentally infected and naturally infected horses. The results were compared to those obtained using molecular tests. The detection limits of the 22 RAD tests varied hugely. Even the four RAD tests showing the best sensitivity were 125-fold less sensitive than the molecular techniques. The duration of virus detection in the experimentally infected horses was shorter using the RAD tests than using the molecular techniques. The RAD tests detected between 27% and 73% of real-time RT-PCR-positive samples from naturally infected horses. The study demonstrated the importance of choosing the right RAD tests as only three of 22 were fit for diagnosing EI. It was also indicated that even RAD tests with the highest sensitivity serve only as an adjunct to molecular tests because of the potential for false-negative results. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Whole-Genome Characterization of a Novel Human Influenza A(H1N2) Virus Variant, Brazil

PubMed Central

Born, Priscila Silva; Matos, Aline Rocha; Motta, Fernando Couto; Caetano, Braulia Costa; Debur, Maria do Carmo; Riediger, Irina Nastassja; Brown, David; Siqueira, Marilda M.

2017-01-01

We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes). PMID:27983507

Whole-Genome Characterization of a Novel Human Influenza A(H1N2) Virus Variant, Brazil.

PubMed

Resende, Paola Cristina; Born, Priscila Silva; Matos, Aline Rocha; Motta, Fernando Couto; Caetano, Braulia Costa; Debur, Maria do Carmo; Riediger, Irina Nastassja; Brown, David; Siqueira, Marilda M

2017-01-01

We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes).

Influenza virus A (H10N7) in chickens and poultry abattoir workers, Australia.

PubMed

Arzey, George G; Kirkland, Peter D; Arzey, K Edla; Frost, Melinda; Maywood, Patrick; Conaty, Stephen; Hurt, Aeron C; Deng, Yi-Mo; Iannello, Pina; Barr, Ian; Dwyer, Dominic E; Ratnamohan, Mala; McPhie, Kenneth; Selleck, Paul

2012-05-01

In March 2010, an outbreak of low pathogenicity avian influenza A (H10N7) occurred on a chicken farm in Australia. After processing clinically normal birds from the farm, 7 abattoir workers reported conjunctivitis and minor upper respiratory tract symptoms. Influenza virus A subtype H10 infection was detected in 2 workers.

Possible role of songbirds and parakeets in transmission of influenza A(H7N9) virus to humans.

PubMed

Jones, Jeremy C; Sonnberg, Stephanie; Koçer, Zeynep A; Shanmuganatham, Karthik; Seiler, Patrick; Shu, Yuelong; Zhu, Huachen; Guan, Yi; Peiris, Malik; Webby, Richard J; Webster, Robert G

2014-03-01

Avian-origin influenza A(H7N9) recently emerged in China, causing severe human disease. Several subtype H7N9 isolates contain influenza genes previously identified in viruses from finch-like birds. Because wild and domestic songbirds interact with humans and poultry, we investigated the susceptibility and transmissibility of subtype H7N9 in these species. Finches, sparrows, and parakeets supported replication of a human subtype H7N9 isolate, shed high titers through the oropharyngeal route, and showed few disease signs. Virus was shed into water troughs, and several contact animals seroconverted, although they shed little virus. Our study demonstrates that a human isolate can replicate in and be shed by such songbirds and parakeets into their environment. This finding has implications for these birds' potential as intermediate hosts with the ability to facilitate transmission and dissemination of A(H7N9) virus.

Possible Role of Songbirds and Parakeets in Transmission of Influenza A(H7N9) Virus to Humans

PubMed Central

Jones, Jeremy C.; Sonnberg, Stephanie; Koçer, Zeynep A.; Shanmuganatham, Karthik; Seiler, Patrick; Shu, Yuelong; Zhu, Huachen; Guan, Yi; Peiris, Malik; Webby, Richard J.

2014-01-01

Avian-origin influenza A(H7N9) recently emerged in China, causing severe human disease. Several subtype H7N9 isolates contain influenza genes previously identified in viruses from finch-like birds. Because wild and domestic songbirds interact with humans and poultry, we investigated the susceptibility and transmissibility of subtype H7N9 in these species. Finches, sparrows, and parakeets supported replication of a human subtype H7N9 isolate, shed high titers through the oropharyngeal route, and showed few disease signs. Virus was shed into water troughs, and several contact animals seroconverted, although they shed little virus. Our study demonstrates that a human isolate can replicate in and be shed by such songbirds and parakeets into their environment. This finding has implications for these birds’ potential as intermediate hosts with the ability to facilitate transmission and dissemination of A(H7N9) virus. PMID:24572739

Lessons from the Largest Epidemic of Avian Influenza Viruses in Taiwan, 2015.

PubMed

Chang, Ching-Fen; King, Chwan-Chuen; Wan, Cho-Hua; Chang, Yun-Cheng; Chan, Ta-Chien; David Lee, Chang-Chun; Chou, Po-Hao Borris; Li, Zheng-Rong Tiger; Li, Yao-Tsun; Tseng, Tzu-Jung; Lee, Pei-Fen; Chang, Chuan-Hsiung

2016-05-01

The largest epidemic of avian influenza (AI) in history attacked poultry and wild birds throughout Taiwan starting January 6, 2015. This study analyzed surveillance results, epidemiologic characteristics, and viral sequences by using government-released information, with the intention to provide recommendations to minimize future pandemic influenza. The H5 clade 2.3.4.4 highly pathogenic AI viruses (HPAIVs) had not been detected in Taiwan before 2015. During this epidemic, four types of etiologic agents were identified: the three novel subtypes H5N2, H5N8, and H5N3 clade 2.3.4.4 HPAIVs and one endemic chicken H5N2 subtype (Mexican-like lineage) of low pathogenic AI viruses. Cocirculation of mixed subtypes also occurred, with H5N2 clade 2.3.4.4 HPAIVs accompanied by the H5N8 and H5N3 subtypes or old H5N2 viruses in the same farm. More than 90% of domestic geese died from this AI epidemic; geese were affected the most at the early outbreaks. The epidemic peaked in mid-January for all three novel H5 subtypes. Spatial epidemiology found that most affected areas were located in southwestern coastal areas. In terrestrial poultry (mostly chickens), different geographic distributions of AI virus subtypes were detected, with hot spots of H5N2 clade 2.3.4.4 vs. past-endemic old H5N2 viruses in Changhwa (P = 0.03) and Yunlin (P = 0.007) counties, respectively, of central Taiwan. Phylogenetic and sequence analyses of all the early 10 Taiwan H5 clade 2.3.4.4 isolates covering the three subtypes showed that they were very different from the HA of the past local H5 viruses from domestic ducks (75%-80%) and chickens (70%-75%). However, they had the highest sequence identity percentages (99.53%-100%), with the HA of A/crane/Kagoshima/KU13/2014(H5N8) isolated on December 7, 2014, in Japan being higher than those of recent American and Korean H5 HPAIVs [A/Northern pintail/Washington/40964/2014 (H5N2) and A/gyrfalcon/Washington/41088-6/2014 (H5N8): 99.02%-99.54% and A/Baikal teal

Influenza A virus and secondary bacterial infection in swine

USDA-ARS?s Scientific Manuscript database

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...

Highly pathogenic avian influenza virus among wild birds in Mongolia

USDA-ARS?s Scientific Manuscript database

The central Asian country of Mongolia supports large populations of migratory water birds that migrate across much of Asia where highly pathogenic avian influenza (HPAI) virus subtype H5N1 is endemic. This, together with the near absence of domestic poultry, makes Mongolia an ideal location to unde...

Identification of reassortant pandemic H1N1 influenza virus in Korean pigs.

PubMed

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

2012-05-01

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

Risk factors for avian influenza virus in backyard poultry flocks and environments in Zhejiang Province, China: a cross-sectional study.

PubMed

Wang, Xiao-Xiao; Cheng, Wei; Yu, Zhao; Liu, She-Lan; Mao, Hai-Yan; Chen, En-Fu

2018-06-19

Human infection of avian influenza virus (AIV) remains a great concern. Although live poultry markets are believed to be associated with human infections, ever more infections have been reported in rural areas with backyard poultry, especially in the fifth epidemic of H7N9. However, limited information is available on backyard poultry infection and surrounding environmental contamination. Two surveillance systems and a field survey were used to collect data and samples in Zhejiang Province. In total, 4538 samples were collected by surveillance systems and 3171 from the field survey between May 2015 and May 2017, while 352 backyard poultry owners were interviewed in May 2017 by questionnaire to investigate factors influencing the prevalence of avian influenza A virus and other AIV subtypes. RT-PCR was used to test the nucleic acids of viruses. ArcGIS 10.1 software was used to generate maps. Univariate and logistic regression analyses were conducted to identify risk factors for AIV infection. Of the 428 poultry premises observed by the surveillance system, 53 (12.38%) were positive for influenza A virus. Of the 352 samples from poultry premises observed by field survey, 13 (3.39%) were positive for influenza A virus. The prevalence of AIV was unevenly distributed and the dominant subtype differed among cities. Eastern (Shaoxing and Ningbo) and southern (Wenzhou) cities exhibited a higher prevalence of AIV (16.33, 8.94, and 7.30% respectively). Contamination of AIV subtypes was most severe in January, especially in 2016 (23.26%, 70/301). The positive rate of subtype H5/H7/H9 was 2.53% (115/4538). Subtype H5 was the least prevalent, while subtypes H7 and H9 had similar positivity rates (1.50 and 1.32% respectively). Poultry flocks and environmental samples had a similar prevalence of AIV (4.46% vs 5.06%). The type of live birds was a risk factor and the sanitary condition of the setting was a protective factor against influenza A contamination. AIV subtypes were

H7N2 feline influenza virus evaluated in a poultry model

USDA-ARS?s Scientific Manuscript database

In November and December of 2016 a novel influenza virus was isolated from cats from an animal shelter from New York City(NYC). The virus caused respiratory disease and was found in cats in several shelters in NYC, and one human also became infected. The H7N2 subtype isolate was sequenced and it w...

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

PubMed

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

2009-10-28

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

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

Transmission of influenza A viruses between pigs and people, Iowa, 2002-2004.

PubMed

Terebuh, Pauline; Olsen, Christopher W; Wright, Jennifer; Klimov, Alexander; Karasin, Alexander; Todd, Karla; Zhou, Hong; Hall, Henrietta; Xu, Xiyan; Kniffen, Tim; Madsen, David; Garten, Rebecca; Bridges, Carolyn B

2010-11-01

Triple-reassortant (tr) viruses of human, avian, and swine origin, including H1N1, H1N2, and H3N2 subtypes, emerged in North American swine herds in 1998 and have become predominant. While sporadic human infections with classical influenza A (H1N1) and with tr-swine influenza viruses have been reported, relatively few have been documented in occupationally exposed swine workers (SW). We conducted a 2-year (2002-2004) prospective cohort study of transmission of influenza viruses between pigs and SW from a single pork production company in Iowa. Respiratory samples were collected and tested for influenza viruses from SW and from pigs under their care through surveillance for influenza-like illnesses (ILI). Serial blood samples from study participants were tested by hemagglutination inhibition (HI) for antibody seroconversion against human and swine influenza viruses (SIV), and antibody seroprevalence was compared to age-matched urban Iowa blood donors. During the first year, 15 of 88 SW had ILI and were sampled; all were culture-negative for influenza. During the second year, 11 of 76 SW had ILI and were sampled; one was culture-positive for a human seasonal H3N2 virus. Among 20 swine herd ILI outbreaks sampled, influenza A virus was detected by rRT-PCR from 17 with 11 trH1N1 and five trH3N2 virus isolates cultured. During both years, HI geometric mean titers were significantly higher among SW compared to blood donor controls for three SIV: classical swine Sw/WI/238/97 (H1N1), tr Sw/IN/9K035/99 (H1N2), and trSw/IA/H02NJ56371/02 (H1N1)] (P < 0·0001). SW had serologic evidence for infection with both swine and human influenza viruses and were exposed to diverse influenza virus strains circulating in pigs. Influenza virus surveillance among pigs and SW should be encouraged to better understand cross-species transmission and diversity of influenza viruses at the human-swine interface. © 2010 Blackwell Publishing Ltd.

A High Diversity of Eurasian Lineage Low Pathogenicity Avian Influenza A Viruses Circulate among Wild Birds Sampled in Egypt

PubMed Central

Gerloff, Nancy A.; Jones, Joyce; Simpson, Natosha; Balish, Amanda; ElBadry, Maha Adel; Baghat, Verina; Rusev, Ivan; de Mattos, Cecilia C.; de Mattos, Carlos A.; Zonkle, Luay Elsayed Ahmed; Kis, Zoltan; Davis, C. Todd; Yingst, Sam; Cornelius, Claire; Soliman, Atef; Mohareb, Emad; Klimov, Alexander; Donis, Ruben O.

2013-01-01

Surveillance for influenza A viruses in wild birds has increased substantially as part of efforts to control the global movement of highly pathogenic avian influenza A (H5N1) virus. Studies conducted in Egypt from 2003 to 2007 to monitor birds for H5N1 identified multiple subtypes of low pathogenicity avian influenza A viruses isolated primarily from migratory waterfowl collected in the Nile Delta. Phylogenetic analysis of 28 viral genomes was performed to estimate their nearest ancestors and identify possible reassortants. Migratory flyway patterns were included in the analysis to assess gene flow between overlapping flyways. Overall, the viruses were most closely related to Eurasian, African and/or Central Asian lineage low pathogenicity viruses and belonged to 15 different subtypes. A subset of the internal genes seemed to originate from specific flyways (Black Sea-Mediterranean, East African-West Asian). The remaining genes were derived from a mixture of viruses broadly distributed across as many as 4 different flyways suggesting the importance of the Nile Delta for virus dispersal. Molecular clock date estimates suggested that the time to the nearest common ancestor of all viruses analyzed ranged from 5 to 10 years, indicating frequent genetic exchange with viruses sampled elsewhere. The intersection of multiple migratory bird flyways and the resulting diversity of influenza virus gene lineages in the Nile Delta create conditions favoring reassortment, as evident from the gene constellations identified by this study. In conclusion, we present for the first time a comprehensive phylogenetic analysis of full genome sequences from low pathogenic avian influenza viruses circulating in Egypt, underscoring the significance of the region for viral reassortment and the potential emergence of novel avian influenza A viruses, as well as representing a highly diverse influenza A virus gene pool that merits continued monitoring. PMID:23874653

Swine Influenza/Variant Influenza Viruses

MedlinePlus

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

Development of high-yield influenza B virus vaccine viruses

PubMed Central

Ping, Jihui; Lopes, Tiago J. S.; Neumann, Gabriele; Kawaoka, Yoshihiro

2016-01-01

The burden of human infections with influenza A and B viruses is substantial, and the impact of influenza B virus infections can exceed that of influenza A virus infections in some seasons. Over the past few decades, viruses of two influenza B virus lineages (Victoria and Yamagata) have circulated in humans, and both lineages are now represented in influenza vaccines, as recommended by the World Health Organization. Influenza B virus vaccines for humans have been available for more than half a century, yet no systematic efforts have been undertaken to develop high-yield candidates. Therefore, we screened virus libraries possessing random mutations in the six “internal” influenza B viral RNA segments [i.e., those not encoding the major viral antigens, hemagglutinin (HA) and neuraminidase NA)] for mutants that confer efficient replication. Candidate viruses that supported high yield in cell culture were tested with the HA and NA genes of eight different viruses of the Victoria and Yamagata lineages. We identified combinations of mutations that increased the titers of candidate vaccine viruses in mammalian cells used for human influenza vaccine virus propagation and in embryonated chicken eggs, the most common propagation system for influenza viruses. These influenza B virus vaccine backbones can be used for improved vaccine virus production. PMID:27930325

Development of high-yield influenza B virus vaccine viruses.

PubMed

Ping, Jihui; Lopes, Tiago J S; Neumann, Gabriele; Kawaoka, Yoshihiro

2016-12-20

The burden of human infections with influenza A and B viruses is substantial, and the impact of influenza B virus infections can exceed that of influenza A virus infections in some seasons. Over the past few decades, viruses of two influenza B virus lineages (Victoria and Yamagata) have circulated in humans, and both lineages are now represented in influenza vaccines, as recommended by the World Health Organization. Influenza B virus vaccines for humans have been available for more than half a century, yet no systematic efforts have been undertaken to develop high-yield candidates. Therefore, we screened virus libraries possessing random mutations in the six "internal" influenza B viral RNA segments [i.e., those not encoding the major viral antigens, hemagglutinin (HA) and neuraminidase NA)] for mutants that confer efficient replication. Candidate viruses that supported high yield in cell culture were tested with the HA and NA genes of eight different viruses of the Victoria and Yamagata lineages. We identified combinations of mutations that increased the titers of candidate vaccine viruses in mammalian cells used for human influenza vaccine virus propagation and in embryonated chicken eggs, the most common propagation system for influenza viruses. These influenza B virus vaccine backbones can be used for improved vaccine virus production.

Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil.

PubMed

Schmidt, C; Cibulski, S P; Andrade, C P; Teixeira, T F; Varela, A P M; Scheffer, C M; Franco, A C; de Almeida, L L; Roehe, P M

2016-05-01

Despite the putative endemic status of swine influenza A virus (swIAV) infections, data on the occurrence of swine influenza outbreaks are scarce in Brazil. The aim of this study was to detect and subtype swIAVs from six outbreaks of porcine respiratory disease complex (PRDC) in southern Brazil. Nasal swabs were collected from 66 piglets with signs of respiratory disease in six herds. Lung tissue samples were collected from six necropsied animals. Virus detection was performed by PCR screening and confirmed by virus isolation and hemagglutination (HA). Influenza A subtyping was performed by a real-time reverse transcriptase PCR (rRT-PCR) to detect the A(H1N1)pdm09; other swIAV subtypes were determined by multiplex RT-PCR. In lung tissues, the major bacterial and viral pathogens associated with PRDC (Pasteurella multocida, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and PCV2) were investigated. In some affected pigs, clinico-pathological evaluations were conducted. Influenza A was detected by screening PCR in 46 of 66 swab samples and from five of six lungs. Virus was recovered from pigs of all six herds. Subtype A(H1N1)pdm09 was detected in four of six herds and H1N2 in the other two herds. In lung tissues, further agents involved in PRDC were detected in all cases; Pasteurella multocida was identified in five of six samples and Mycoplasma hyopneumoniae in three of six. Actinobacillus pleuropneumoniae (1/6), Haemophilus parasuis (1/6) and PCV2 (1/6) were also detected. These findings indicate that subtypes A(H1N1)pdm09 and H1N2 were present in pigs in southern Brazil and were associated with PRDC outbreaks. © 2015 Blackwell Verlag GmbH.

The Genetic Diversity of Influenza A Viruses in Wild Birds in Peru

PubMed Central

Nelson, Martha I.; Pollett, Simon; Ghersi, Bruno; Silva, Maria; Simons, Mark P.; Icochea, Eliana; Gonzalez, Armando E.; Segovia, Karen; Kasper, Matthew R.; Montgomery, Joel M.; Bausch, Daniel G.

2016-01-01

Our understanding of the global ecology of avian influenza A viruses (AIVs) is impeded by historically low levels of viral surveillance in Latin America. Through sampling and whole-genome sequencing of 31 AIVs from wild birds in Peru, we identified 10 HA subtypes (H1-H4, H6-H7, H10-H13) and 8 NA subtypes (N1-N3, N5-N9). The majority of Peruvian AIVs were closely related to AIVs found in North America. However, unusual reassortants, including a H13 virus containing a PA segment related to extremely divergent Argentinian viruses, suggest that substantial AIV diversity circulates undetected throughout South America. PMID:26784331

Optical fiber sensor based on surface plasmon resonance for rapid detection of avian influenza virus subtype H6: Initial studies.

PubMed

Zhao, Xihong; Tsao, Yu-Chia; Lee, Fu-Jung; Tsai, Woo-Hu; Wang, Ching-Ho; Chuang, Tsung-Liang; Wu, Mu-Shiang; Lin, Chii-Wann

2016-07-01

A side-polished fiber optic surface plasmon resonance (SPR) sensor was fabricated to expose the core surface and then deposited with a 40 nm thin gold film for the near surface sensing of effective refractive index changes with surface concentration or thickness of captured avian influenza virus subtype H6. The detection surface of the SPR optical fiber sensor was prepared through the plasma modification method for binding a self-assembled monolayer of isopropanol chemically on the gold surface of the optical fiber. Subsequently, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide was activated to enable EB2-B3 monoclonal antibodies to capture A/chicken/Taiwan/2838V/00 (H6N1) through a flow injection system. The detection limit of the fabricated optical fiber sensor for A/chicken/Taiwan/2838V/00 was 5.14 × 10(5) EID50/0.1 mL, and the response time was 10 min on average. Moreover, the fiber optic sensor has the advantages of a compact size and low cost, thus rendering it suitable for online and remote sensing. The results indicated that the optical fiber sensor can be used for epidemiological surveillance and diagnosing of avian influenza subtype H6 rapidly. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular epidemiology of H9N2 influenza viruses in Northern Europe.

PubMed

Lindh, Erika; Ek-Kommonen, Christine; Väänänen, Veli-Matti; Vaheri, Antti; Vapalahti, Olli; Huovilainen, Anita

2014-08-27

Low pathogenic avian influenza viruses are maintained in wild bird populations throughout the world. Avian influenza viruses are characterized by their efficient ability to reassort and adapt, which enables them to cross the species barrier and enhances their zoonotic potential. Influenza viruses of the H9N2 subtype appear endemic among poultry in Eurasia. They usually exist as low-pathogenic strains and circulate between wild bird populations, poultry and birds sold at live bird markets. Direct transmission of H9N2 viruses, with receptor specificities similar to human influenza strains, to pigs and humans has been reported on several occasions. H9N2 virus was first encountered in Finland in 2009, during routine screening of hunted wild waterfowl. The next year, H9N2 influenza viruses were isolated from wild birds on four occasions, including once from a farmed mallard. We have investigated the relationship between the reared and wild bird isolates by sequencing the hemagglutinin and the neuraminidase genes of the Finnish H9N2 viruses. Nucleotide sequence comparison and phylogenetic analyses indicate that H9N2 was transmitted from wild birds to reared birds in 2010, and that highly identical strains have been circulating in Europe during the last few years. Copyright © 2014 Elsevier B.V. All rights reserved.

A genetically adjuvanted influenza B virus vector increases immunogenicity and protective efficacy in mice.

PubMed

Kittel, Christian; Wressnigg, Nina; Shurygina, Anna Polina; Wolschek, Markus; Stukova, Marina; Romanovskaya-Romanko, Ekatherina; Romanova, Julia; Kiselev, Oleg; Muster, Thomas; Egorov, Andrej

2015-10-01

The existence of multiple antigenically distinct types and subtypes of influenza viruses allows the construction of a multivalent vector system for the mucosal delivery of foreign sequences. Influenza A viruses have been exploited successfully for the expression of extraneous antigens as well as immunostimulatory molecules. In this study, we describe the development of an influenza B virus vector whose functional part of the interferon antagonist NS1 was replaced by human interleukin 2 (IL2) as a genetic adjuvant. We demonstrate that IL2 expressed by this viral vector displays immune adjuvant activity in immunized mice. Animals vaccinated with the IL2 viral vector showed an increased hemagglutination inhibition antibody response and higher protective efficacy after challenge with a wild-type influenza B virus when compared to mice vaccinated with a control virus. Our results demonstrate that it is feasible to construct influenza B vaccine strains expressing immune-potentiating foreign sequences from the NS genomic segment. Based on these data, it is now hypothetically possible to create a trivalent (or quadrivalent) live attenuated influenza vaccine in which each component expresses a selected genetic adjuvant with tailored expression levels.

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

PubMed

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

2017-12-01

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

Avian Influenza A(H5N1) Virus in Egypt.

PubMed

Kayali, Ghazi; Kandeil, Ahmed; El-Shesheny, Rabeh; Kayed, Ahmed S; Maatouq, Asmaa M; Cai, Zhipeng; McKenzie, Pamela P; Webby, Richard J; El Refaey, Samir; Kandeel, Amr; Ali, Mohamed A

2016-03-01

In Egypt, avian influenza A subtype H5N1 and H9N2 viruses are enzootic in poultry. The control plan devised by veterinary authorities in Egypt to prevent infections in poultry focused mainly on vaccination and ultimately failed. Recently, widespread H5N1 infections in poultry and a substantial increase in the number of human cases of H5N1 infection were observed. We summarize surveillance data from 2009 through 2014 and show that avian influenza viruses are established in poultry in Egypt and are continuously evolving genetically and antigenically. We also discuss the epidemiology of human infection with avian influenza in Egypt and describe how the true burden of disease is underestimated. We discuss the failures of relying on vaccinating poultry as the sole intervention tool. We conclude by highlighting the key components that need to be included in a new strategy to control avian influenza infections in poultry and humans in Egypt.

Avian Influenza A(H5N1) Virus in Egypt

PubMed Central

Kandeil, Ahmed; El-Shesheny, Rabeh; Kayed, Ahmed S.; Maatouq, Asmaa M.; Cai, Zhipeng; McKenzie, Pamela P.; Webby, Richard J.; El Refaey, Samir; Kandeel, Amr; Ali, Mohamed A.

2016-01-01

In Egypt, avian influenza A subtype H5N1 and H9N2 viruses are enzootic in poultry. The control plan devised by veterinary authorities in Egypt to prevent infections in poultry focused mainly on vaccination and ultimately failed. Recently, widespread H5N1 infections in poultry and a substantial increase in the number of human cases of H5N1 infection were observed. We summarize surveillance data from 2009 through 2014 and show that avian influenza viruses are established in poultry in Egypt and are continuously evolving genetically and antigenically. We also discuss the epidemiology of human infection with avian influenza in Egypt and describe how the true burden of disease is underestimated. We discuss the failures of relying on vaccinating poultry as the sole intervention tool. We conclude by highlighting the key components that need to be included in a new strategy to control avian influenza infections in poultry and humans in Egypt. PMID:26886164

Immunogenicity of modified vaccinia virus Ankara expressing the hemagglutinin stalk domain of pandemic (H1N1) 2009 influenza virus.

PubMed

Di Mario, Giuseppina; Soprana, Elisa; Gubinelli, Francesco; Panigada, Maddalena; Facchini, Marzia; Fabiani, Concetta; Garulli, Bruno; Basileo, Michela; Cassone, Antonio; Siccardi, Antonio; Donatelli, Isabella; Castrucci, Maria R

2017-03-01

Vaccination offers protection against influenza, although current vaccines need to be reformulated each year. The development of a broadly protective influenza vaccine would guarantee the induction of heterosubtypic immunity also against emerging influenza viruses of a novel subtype. Vaccine candidates based on the stalk region of the hemagglutinin (HA) have the potential to induce broad and persistent protection against diverse influenza A viruses. Modified vaccinia virus Ankara (MVA) expressing a headless HA (hlHA) of A/California/4/09 (CA/09) virus was used as a vaccine to immunize C57BL/6 mice. Specific antibody and cell-mediated immune responses were determined, and challenge experiments were performed by infecting vaccinated mice with CA/09 virus. Immunization of mice with CA/09-derived hlHA, vectored by MVA, was able to elicit influenza-specific broad cross-reactive antibodies and cell-mediated immune responses, but failed to induce neutralizing antibodies and did not protect mice against virus challenge. Although highly immunogenic, our vaccine was unable to induce a protective immunity against influenza. A misfolded and unstable conformation of the hlHA molecule may have affected its capacity of inducing neutralizing antiviral, conformational antibodies. Design of stable hlHA-based immunogens and their delivery by recombinant MVA-based vectors has the potential of improving this promising approach for a universal influenza vaccine.

Genomic characterization of H14 subtype influenza A viruses in New World waterfowl and experimental infectivity in mallards Anas platyrhynchos

USGS Publications Warehouse

Ramey, Andy M.; Poulson, Rebecca L.; Gonzalez-Reiche, Ana S.; Perez, Daniel R.; Stalknecht, David E.; Brown, Justin D.

2014-01-01

Recent repeated isolation of H14 hemagglutinin subtype influenza A viruses (IAVs) in the New World waterfowl provides evidence to suggest that host and/or geographic ranges for viruses of this subtype may be expanding. In this study, we used genomic analyses to gain inference on the origin and evolution of H14 viruses in New World waterfowl and conducted an experimental challenge study in mallards (Anas platyrhynchos) to evaluate pathogenicity, viral replication, and transmissibility of a representative viral strain in a natural host species. Genomic characterization of H14 subtype IAVs isolated from New World waterfowl, including three isolates sequenced specifically for this study, revealed high nucleotide identity among individual gene segments (e.g. ≥95% shared identity among H14 HA gene segments). In contrast, lower shared identity was observed among internal gene segments. Furthermore, multiple neuraminidase subtypes were observed for H14 IAVs isolated in the New World. Gene segments of H14 viruses isolated after 2010 shared ancestral genetic lineages with IAVs isolated from wild birds throughout North America. Thus, genomic characterization provided evidence for viral evolution in New World waterfowl through genetic drift and genetic shift since purported introduction from Eurasia. In the challenge study, no clinical disease or lesions were observed among mallards experimentally inoculated with A/blue-winged teal/Texas/AI13-1028/2013(H14N5) or exposed via contact with infected birds. Titers of viral shedding for mallards challenged with the H14N5 IAV were highest at two days post-inoculation (DPI); however shedding was detected up to nine DPI using cloacal swabs. The distribution of viral antigen among mallards infected with H14N5 IAV was largely restricted to enterocytes lining the villi in the lower intestinal tract and in the epithelium of the bursa of Fabricius. Characterization of the infectivity of A/blue-winged teal/Texas/AI13-1028/2013(H14N5) in

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

PubMed

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

2017-08-03

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

Oral fluids as a live-animal sample for evaluating cross-reactivity and cross-protection following intranasal influenza A virus vaccination in pigs

USDA-ARS?s Scientific Manuscript database

In North American swine there are numerous antigenically distinct influenza A virus (IAV) H1 subtypes currently circulating, making vaccine development difficult due to the inability to formulate a vaccine that provides broad cross-protection. Live-attenuated influenza virus (LAIV) vaccines provide ...

The pathogenesis of H3N8 canine influenza virus in chickens and turkeys

USDA-ARS?s Scientific Manuscript database

Canine influenza virus (CIV) of the H3N8 subtype has emerged in dog populations throughout the U.S. where it has become endemic in kennels and animal shelters in some regions of the U.S. CIV is believed to be an equine influenza that was transmitted to and adapted to dogs. It has not previously bee...

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

PubMed

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

2010-09-01

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

The evolving threat of influenza viruses of animal origin and the challenges in developing appropriate diagnostics.

PubMed

Mak, Polly W Y; Jayawardena, Shanthi; Poon, Leo L M

2012-11-01

An H1N1 subtype of swine origin caused the first influenza pandemic in this century. This pandemic strain was a reassortant of avian, swine, and human influenza viruses. Many diagnostic laboratories were overwhelmed by the testing demands related to this pandemic. Nevertheless, there remains the threat of other animal influenza viruses, such as highly pathogenic H5N1. As a part of pandemic preparedness, it is essential to identify the diagnostic challenges that will accompany the next pandemic. We discuss the natural reservoir of influenza viruses and the possible role of livestock in the emergence of pandemic strains. The current commonly used molecular tests for influenza diagnosis or surveillance are also briefly reviewed. Some of these approaches are also used to detect animal viruses. Unfortunately, owing to a lack of systematic surveillance of animal influenza viruses, established tests may not be able to detect pandemic strains that have yet to emerge from the animal reservoir. Thus, multiple strategies need to be developed for better identification of influenza viruses. In addition, molecular assays for detection of mutations associated with antiviral resistance and for viral segment reassortments should also be encouraged. Influenza viruses are highly dynamic viruses. Regular and systematic influenza surveillance in both humans and animals is essential to provide a more comprehensive picture of the prevalent influenza viruses. To better prepare for the next pandemic, we should develop some simple and easy-to-use tests for characterizing newly emerging influenza viruses. © 2012 American Association for Clinical Chemistry

Broad spectrum reactivity versus subtype specificity-trade-offs in serodiagnosis of influenza A virus infections by competitive ELISA.

PubMed

Postel, A; Ziller, M; Rudolf, M; Letzel, T; Ehricht, Ralf; Pourquier, P; Dauber, M; Grund, C; Beer, Martin; Harder, T C

2011-04-01

Avian influenza viruses (AIVs) of the H5 and H7 subtypes can cause substantial economic losses in the poultry industry and are a potential threat to public health. Serosurveillance of poultry populations is an important monitoring tool and can also be used for control of vaccination campaigns. The purpose of this study was to develop broadly reactive, yet subtype-specific competitive ELISAs (cELISAs) for the specific detection of antibodies to the notifiable AIV subtypes H5 and H7 as an alternative to the gold standard haemagglutination inhibition assay (HI). Broadly reacting monoclonal competitor antibodies (mAbs) and genetically engineered subtype H5 or H7 haemagglutinin antigen, expressed and in vivo biotinylated in insect cells, were used to develop the cELISAs. Sera from galliform species and water fowl (n=793) were used to evaluate the performance characteristics of the cELISAs. For the H5 specific cELISA, 98.1% test sensitivity and 91.5% test specificity (97.7% and 90.2% for galliforms; 98.9% and 92.6% for waterfowl), and for the H7 cELISA 97.3% sensitivity and 91.8% specificity (95.3% and 98.9% for galliforms; 100% and 82.7% for waterfowl) were reached when compared to HI. The use of competitor mAbs with broad spectrum reactivity within an AIV haemagglutinin subtype allowed for homogenous detection with high sensitivity of subtype-specific antibodies induced by antigenically widely distinct isolates including antigenic drift variants. However, a trade-off regarding sensitivity versus nonspecific detection of interfering antibodies induced by phylo- and antigenically closely related subtypes, e.g., H5 versus H2 and H7 versus H15, must be considered. The observed intersubtype antibody cross-reactivity remains a disturbance variable in AIV subtype-specific serodiagnosis which negatively affects specificity. Copyright © 2011 Elsevier B.V. All rights reserved.

Introduction of 2009 pandemic influenza A virus subtype H1N1 into South Africa: clinical presentation, epidemiology, and transmissibility of the first 100 cases.

PubMed

Archer, Brett N; Timothy, Geraldine A; Cohen, Cheryl; Tempia, Stefano; Huma, Mmampedi; Blumberg, Lucille; Naidoo, Dhamari; Cengimbo, Ayanda; Schoub, Barry D

2012-12-15

We documented the introduction of 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) into South Africa and describe its clinical presentation, epidemiology, and transmissibility. We conducted a prospective descriptive study of the first 100 laboratory-confirmed cases of A(H1N1)pdm09 infections identified through active case finding and surveillance. Infected patients and the attending clinicians were interviewed, and close contacts were followed up to investigate household transmission. The first case was confirmed on 14 June 2009, and by 15 July 2009, 100 cases were diagnosed. Forty-two percent of patients reported international travel within 7 days prior to onset of illness. Patients ranged in age from 4 to 70 years (median age, 21.5 years). Seventeen percent of household contacts developed influenza-like illness, and 10% of household contacts had laboratory-confirmed A(H1N1)pdm09 infection. We found a mean serial interval (± SD) of 2.3 ± 1.3 days (range, 1-5 days) between successive laboratory-confirmed cases in the transmission chain. A(H1N1)pdm09 established itself rapidly in South Africa. Transmissibility of the virus was comparable to observations from outside of Africa and to seasonal influenza virus strains.

Genetic and Antigenic Typing of Seasonal Influenza Virus Breakthrough Cases from a 2008-2009 Vaccine Efficacy Trial

PubMed Central

Durviaux, Serge; Treanor, John; Beran, Jiri; Duval, Xavier; Esen, Meral; Feldman, Gregory; Frey, Sharon E.; Launay, Odile; Leroux-Roels, Geert; McElhaney, Janet E.; Nowakowski, Andrzej; Ruiz-Palacios, Guillermo M.; van Essen, Gerrit A.; Oostvogels, Lidia; Devaster, Jeanne-Marie

2014-01-01

Estimations of the effectiveness of vaccines against seasonal influenza virus are guided by comparisons of the antigenicities between influenza virus isolates from clinical breakthrough cases with strains included in a vaccine. This study examined whether the prediction of antigenicity using a sequence analysis of the hemagglutinin (HA) gene-encoded HA1 domain is a simpler alternative to using the conventional hemagglutination inhibition (HI) assay, which requires influenza virus culturing. Specimens were taken from breakthrough cases that occurred in a trivalent influenza virus vaccine efficacy trial involving >43,000 participants during the 2008-2009 season. A total of 498 influenza viruses were successfully subtyped as A(H3N2) (380 viruses), A(H1N1) (29 viruses), B(Yamagata) (23 viruses), and B(Victoria) (66 viruses) from 603 PCR- or culture-confirmed specimens. Unlike the B strains, most A(H3N2) (377 viruses) and all A(H1N1) viruses were classified as homologous to the respective vaccine strains based on their HA1 domain nucleic acid sequence. HI titers relative to the respective vaccine strains and PCR subtyping were determined for 48% (182/380) of A(H3N2) and 86% (25/29) of A(H1N1) viruses. Eighty-four percent of the A(H3N2) and A(H1N1) viruses classified as homologous by sequence were matched to the respective vaccine strains by HI testing. However, these homologous A(H3N2) and A(H1N1) viruses displayed a wide range of relative HI titers. Therefore, although PCR is a sensitive diagnostic method for confirming influenza virus cases, HA1 sequence analysis appeared to be of limited value in accurately predicting antigenicity; hence, it may be inappropriate to classify clinical specimens as homologous or heterologous to the vaccine strain for estimating vaccine efficacy in a prospective clinical trial. PMID:24371255

Surveillance of avian influenza virus type A in semi-scavenging ducks in Bangladesh

PubMed Central

2013-01-01

Background Ducks are the natural reservoir of influenza A virus and the central host for highly pathogenic avian influenza (H5N1), while domestic ducks rearing in semi-scavenging system could serve as re-assortment vessels for re-emerging new subtypes of influenza viruses between birds to human. Avian influenza virus (AIV) surveillance in Bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic H5N1 influenza. Here, the results of an active surveillance effort focusing on the semi-scavenging ducks are presented. Result A total of 2100 cloacal swabs and 2100 sera were collected from semi-scavenging ducks from three wintering-sites of Bangladesh during three successive winter seasons, December through February in the years between 2009 and 2012. Virus isolation and identification were carried out from the cloacal swabs by virus propagation in embryonated hen eggs followed by amplification of viral RNA using Avian influenza virus (AIV) specific RT-PCR. The overall prevalence of avian influenza type A was 22.05% for swab samples and 39.76% ducks were sero-positive for avian influenza type A antibody. Extremely low sero-prevalence (0.09%) of AIV H5N1 was detected. Conclusions Based on our surveillance results, we conclude that semi-scavenging ducks in Bangladesh might play important role in transmitting Avian Influenza virus (AIV) type A. However, the current risk of infection for humans from domestic ducks in Bangladesh is negligible. We believe that this relatively large dataset over three winters in Bangladesh might create a strong foundation for future studies of AIV prevalence, evolution, and ecology in wintering sites around the globe. PMID:24099526

Influenza HA subtypes demonstrate divergent phenotypes for cleavage activation and pH of fusion: implications for host range and adaptation.

PubMed

Galloway, Summer E; Reed, Mark L; Russell, Charles J; Steinhauer, David A

2013-02-01

The influenza A virus (IAV) HA protein must be activated by host cells proteases in order to prime the molecule for fusion. Consequently, the availability of activating proteases and the susceptibility of HA to protease activity represents key factors in facilitating virus infection. As such, understanding the intricacies of HA cleavage by various proteases is necessary to derive insights into the emergence of pandemic viruses. To examine these properties, we generated a panel of HAs that are representative of the 16 HA subtypes that circulate in aquatic birds, as well as HAs representative of the subtypes that have infected the human population over the last century. We examined the susceptibility of the panel of HA proteins to trypsin, as well as human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2). Additionally, we examined the pH at which these HAs mediated membrane fusion, as this property is related to the stability of the HA molecule and influences the capacity of influenza viruses to remain infectious in natural environments. Our results show that cleavage efficiency can vary significantly for individual HAs, depending on the protease, and that some HA subtypes display stringent selectivity for specific proteases as activators of fusion function. Additionally, we found that the pH of fusion varies by 0.7 pH units among the subtypes, and notably, we observed that the pH of fusion for most HAs from human isolates was lower than that observed from avian isolates of the same subtype. Overall, these data provide the first broad-spectrum analysis of cleavage-activation and membrane fusion characteristics for all of the IAV HA subtypes, and also show that there are substantial differences between the subtypes that may influence transmission among hosts and establishment in new species.

Influenza HA Subtypes Demonstrate Divergent Phenotypes for Cleavage Activation and pH of Fusion: Implications for Host Range and Adaptation

PubMed Central

Galloway, Summer E.; Reed, Mark L.; Russell, Charles J.; Steinhauer, David A.

2013-01-01

The influenza A virus (IAV) HA protein must be activated by host cells proteases in order to prime the molecule for fusion. Consequently, the availability of activating proteases and the susceptibility of HA to protease activity represents key factors in facilitating virus infection. As such, understanding the intricacies of HA cleavage by various proteases is necessary to derive insights into the emergence of pandemic viruses. To examine these properties, we generated a panel of HAs that are representative of the 16 HA subtypes that circulate in aquatic birds, as well as HAs representative of the subtypes that have infected the human population over the last century. We examined the susceptibility of the panel of HA proteins to trypsin, as well as human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2). Additionally, we examined the pH at which these HAs mediated membrane fusion, as this property is related to the stability of the HA molecule and influences the capacity of influenza viruses to remain infectious in natural environments. Our results show that cleavage efficiency can vary significantly for individual HAs, depending on the protease, and that some HA subtypes display stringent selectivity for specific proteases as activators of fusion function. Additionally, we found that the pH of fusion varies by 0.7 pH units among the subtypes, and notably, we observed that the pH of fusion for most HAs from human isolates was lower than that observed from avian isolates of the same subtype. Overall, these data provide the first broad-spectrum analysis of cleavage-activation and membrane fusion characteristics for all of the IAV HA subtypes, and also show that there are substantial differences between the subtypes that may influence transmission among hosts and establishment in new species. PMID:23459660

Contribution of murine innate serum inhibitors toward interference within influenza virus immune assays

PubMed Central

Cwach, Kevin T.; Sandbulte, Heather R.; Klonoski, Joshua M.; Huber, Victor C.

2011-01-01

Please cite this paper as: Cwach et al. (2011) Contribution of murine innate serum inhibitors toward interference within influenza virus immune assays. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2011.00283.x. Background  Prior to detection of an antibody response toward influenza viruses using the hemagglutination inhibition assay (HAI), sera are routinely treated to inactivate innate inhibitors using both heat inactivation (56°C) and recombinant neuraminidase [receptor‐destroying enzyme (RDE)]. Objectives  We revisited the contributions of innate serum inhibitors toward interference with influenza viruses in immune assays, using murine sera, with emphasis on the interactions with influenza A viruses of the H3N2 subtype. Methods  We used individual serum treatments: 56°C alone, RDE alone, or RDE + 56°C, to treat sera prior to evaluation within HAI, microneutralization, and macrophage uptake assays. Results  Our data demonstrate that inhibitors present within untreated murine sera interfere with the HAI assay in a manner that is different from that seen for the microneutralization assay. Specifically, the γ class inhibitor α2‐Macroglobulin (A2‐M) can inhibit H3N2 viruses within the HAI assay, but not in the microneutralization assay. Based on these findings, we used a macrophage uptake assay to demonstrate that these inhibitors can increase uptake by macrophages when the influenza viruses express an HA from a 1968 H3N2 virus isolate, but not a 1997 H3N2 isolate. Conclusions  The practice of treating sera to inactivate innate inhibitors of influenza viruses prior to evaluation within immune assays has allowed us to effectively detect influenza virus‐specific antibodies for decades. However, this practice has yielded an under‐appreciation for the contribution of innate serum inhibitors toward host immune responses against these viruses, including contributions toward neutralization and macrophage uptake. PMID

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

PubMed