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Sample records for influenza virus haemagglutinin

  1. 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

    2016-01-01

    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

  2. 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

  3. Exploring the antigenic relatedness of influenza virus haemagglutinins with strain-specific polyclonal antibodies.

    PubMed

    García-Barreno, Blanca; Delgado, Teresa; Benito, Sonia; Casas, Inmaculada; Pozo, Francisco; Melero, José A

    2014-10-01

    Alternative methods to the standard haemagglutination inhibition (HI) and neutralization tests to probe the antigenic properties of the influenza virus haemagglutinin (HA) were developed in this study. Vaccinia virus recombinants expressing reference HAs were used to immunize rabbits from which polyclonal antibodies were obtained. These antibodies were subtype specific but showed limited intra-subtype strain specificity in ELISA. The discriminatory capacity of these antibodies was, however, markedly increased after adsorption to cells infected with heterologous influenza viruses, revealing antigenic differences that were otherwise undistinguishable by standard HI and neutralization tests. Furthermore, the unadsorbed antibodies could be used to select escape mutants of the reference strain, which after sequencing unveiled amino acid changes responsible of the noted antigenic differences. These procedures therefore provide alternative methods for the antigenic characterization of influenza HA and might be useful in studies of HA antigenic evolution. PMID:25000959

  4. The hemifusion structure induced by influenza virus haemagglutinin is determined by physical properties of the target membranes.

    PubMed

    Chlanda, Petr; Mekhedov, Elena; Waters, Hang; Schwartz, Cindi L; Fischer, Elizabeth R; Ryham, Rolf J; Cohen, Fredric S; Blank, Paul S; Zimmerberg, Joshua

    2016-01-01

    Influenza A virus haemagglutinin conformational change drives the membrane fusion of viral and endosomal membranes at low pH. Membrane fusion proceeds through an intermediate called hemifusion(1,2). For viral fusion, the hemifusion structures are not determined(3). Here, influenza virus-like particles(4) carrying wild-type haemagglutinin or haemagglutinin hemifusion mutant G1S(5) and liposome mixtures were studied at low pH by Volta phase plate cryo-electron tomography, which improves the signal-to-noise ratio close to focus. We determined two distinct hemifusion structures: a hemifusion diaphragm and a novel structure termed a 'lipidic junction'. Liposomes with lipidic junctions were ruptured with membrane edges stabilized by haemagglutinin. The rupture frequency and hemifusion diaphragm diameter were not affected by G1S mutation, but decreased when the cholesterol level in the liposomes was close to physiological concentrations. We propose that haemagglutinin induces a merger between the viral and target membranes by one of two independent pathways: a rupture-insertion pathway leading to the lipidic junction and a hemifusion-stalk pathway leading to a fusion pore. The latter is relevant under the conditions of influenza virus infection of cells. Cholesterol concentration functions as a pathway switch because of its negative spontaneous curvature in the target bilayer, as determined by continuum analysis. PMID:27572837

  5. Human monoclonal antibodies targeting the haemagglutinin glycoprotein can neutralize H7N9 influenza virus.

    PubMed

    Chen, Zhe; Wang, Jianmin; Bao, Linlin; Guo, Li; Zhang, Weijia; Xue, Ying; Zhou, Hongli; Xiao, Yan; Wang, Jianwei; Wu, Fan; Deng, Ying; Qin, Chuan; Jin, Qi

    2015-01-01

    The recently identified avian-originated influenza H7N9 virus causes severe pulmonary disease and may lead to death in humans. Currently, treatment options for the prevention and control of fatal H7N9 infections in humans remain limited. Here we characterize two human monoclonal antibodies (HuMAbs), HNIgGA6 and HNIgGB5, by screening a Fab antibody phage library derived from patients who recovered from H7N9 infection. Both antibodies exhibit high neutralizing activity against H7N9 virus in cells. Two amino acids in the receptor-binding site, 186V and 226L, are crucial for the binding of these two HuMAbs to viral haemagglutinin antigens. Prophylaxis with HNIgGA6 and HNIgGB5 confers significant immunity against H7N9 virus in a mouse model and significantly reduces the pulmonary virus titre. When administered post infection, therapeutic doses of the HuMAbs also provide robust protection against lethality. These antibodies might represent a potential alternative or adjunct to H7N9 pandemic interventions. PMID:25819694

  6. Conformation study of HA(306-318) antigenic peptide of the haemagglutinin influenza virus protein

    NASA Astrophysics Data System (ADS)

    Bertrand, A.; Brito, R. M.; Alix, A. J. P.; Lancelin, J. M.; Carvalho, R. A.; Geraldes, C. F. G. C.; Lakhdar-Ghazal, F.

    2006-11-01

    Several HLA-DR alleles present the immunodominant HA(306-318) peptide of haemagglutinin of the influenza virus to T cells. NMR data of the peptide in various water solutions exclude any α-helix or turn conformations. Circular dichroism and Fourier transform infrared spectroscopies indicate an estimated β-extended structure in water of 31% and 28%, respectively, with spectra shape similar to the ones observed for β-sheet containing proteins. The H/D amide exchange suggests a stable length-dependent interchain hydrogen-bonding. The partially β-extended conformation of HA(306-318) in solution might be close to the one found in HA(306-318)-HLA-DR1 complex. These results suggest different interconverting extended conformations of HA(306-318), depending on the microenvironment of the solution medium. This flexibility emphasizes the ability of some peptides to fit more easily the binding site of several HLA-DR molecules. Similar results were obtained on the HIV P25(263-277) peptide which has been previously shown to be a good DR1 binder. From a vibrational point of view, infrared Amide I frequencies of secondary structures in peptides were ascertained. As previously demonstrated for proteins in solution, Fourier transform infrared and circular dichroism spectroscopies appear to be valuable tools for conformational properties of peptides. Their use may contribute to the detection of peptide conformation-binding relationship which has to be further tested by biochemical and biological studies.

  7. Biochemical composition of haemagglutinin-based influenza virus-like particle vaccine produced by transient expression in tobacco plants.

    PubMed

    Le Mauff, François; Mercier, Geneviève; Chan, Philippe; Burel, Carole; Vaudry, David; Bardor, Muriel; Vézina, Louis-Philippe; Couture, Manon; Lerouge, Patrice; Landry, Nathalie

    2015-06-01

    Influenza virus-like particles (VLPs) are noninfectious particles resembling the influenza virus representing a promising vaccine alternative to inactivated influenza virions as antigens. Medicago inc. has developed a plant-based VLP manufacturing platform allowing the large-scale production of GMP-grade influenza VLPs. In this article, we report on the biochemical compositions of these plant-based influenza candidate vaccines, more particularly the characterization of the N-glycan profiles of the viral haemagglutinins H1 and H5 proteins as well as the tobacco-derived lipid content and residual impurities. Mass spectrometry analyses showed that all N-glycosylation sites of the extracellular domain of the recombinant haemagglutinins carry plant-specific complex-type N-glycans having core α(1,3)-fucose, core β(1,2)-xylose epitopes and Lewis(a) extensions. Previous phases I and II clinical studies have demonstrated that no hypersensibility nor induction of IgG or IgE directed against these glycans was observed. In addition, this article showed that the plant-made influenza vaccines are highly pure VLPs preparations while detecting no protein contaminants coming either from Agrobacterium or from the enzymes used for the enzyme-assisted extraction process. In contrast, VLPs contain few host cell proteins and glucosylceramides associated with plant lipid rafts. Identification of such raft markers, together with the type of host cell impurity identified, confirmed that the mechanism of VLP formation in planta is similar to the natural process of influenza virus assembly in mammals. PMID:25523794

  8. Vaccine-associated enhanced respiratory disease is influenced by haemagglutinin and neuraminidase in whole inactivated influenza virus vaccines.

    PubMed

    Rajão, Daniela S; Chen, Hongjun; Perez, Daniel R; Sandbulte, Matthew R; Gauger, Phillip C; Loving, Crystal L; Shanks, G Dennis; Vincent, Amy

    2016-07-01

    Multiple subtypes and many antigenic variants of influenza A virus (IAV) co-circulate in swine in the USA, complicating effective use of commercial vaccines to control disease and transmission. Whole inactivated virus (WIV) vaccines may provide partial protection against IAV with substantial antigenic drift, but have been shown to induce vaccine-associated enhanced respiratory disease (VAERD) when challenged with an antigenic variant of the same haemagglutinin (HA) subtype. This study investigated the role the immune response against HA, neuraminidase (NA) and nucleoprotein (NP) may play in VAERD by reverse engineering vaccine and challenge viruses on a common backbone and using them in a series of vaccination/challenge trials. Mismatched HA between vaccine and challenge virus was necessary to induce VAERD. However, vaccines containing a matched NA abrogated the VAERD phenomenon induced by the HA mismatch and this was correlated with NA-inhibiting (NI) antibodies. Divergence between the two circulating swine N2 lineages (92 % identity) resulted in a loss of NI cross-reactivity and also resulted in VAERD with the mismatched HA. The NP lineage selected for use in the WIV vaccine strains did not affect protection or pathology. Thus the combination of HA and NA in the vaccine virus strains played a substantial role in vaccine protection versus immunopathology, suggesting that vaccines that target the HA protein alone could be more prone to VAERD due to the absence of cross-protective NI antibodies. PMID:27031847

  9. Reduced susceptibility to all neuraminidase inhibitors of influenza H1N1 viruses with haemagglutinin mutations and mutations in non-conserved residues of the neuraminidase

    PubMed Central

    McKimm-Breschkin, Jennifer L.; Williams, Janelle; Barrett, Susan; Jachno, Kim; McDonald, Mandy; Mohr, Peter G.; Saito, Takehiko; Tashiro, Masato

    2013-01-01

    Objectives We characterized human H1N1 influenza isolate A/Hokkaido/15/02, which has haemagglutinin and neuraminidase mutations that reduce drug susceptibility to oseltamivir, zanamivir and peramivir. Methods One wild-type and three mutant viruses were isolated by plaque purification. Viruses were tested in MUNANA-based enzyme assays, cell culture and receptor binding assays. Results Two viruses had a neuraminidase Y155H mutation that reduced susceptibility in the enzyme inhibition assay to all inhibitors by 30-fold to >100-fold. The Y155H mutation reduced plaque size and affected the stability, Km and pH activity profile of the enzyme. In contrast to previous mutants, this neuraminidase demonstrated a slower rate of inhibitor binding in the IC50 kinetics assay. One virus had both the Y155H mutation and a haemagglutinin D225G mutation that rescued the small-plaque phenotype of the Y155H virus and affected receptor binding and drug susceptibility in cell culture and binding assays. We also isolated a third mutant virus, with both neuraminidase V114I and haemagglutinin D225N mutations, which affected susceptibility in the enzyme inhibition assay and receptor binding, respectively, but to lesser extents than the Y155H and D225G mutations. Conclusions Neither Y155 nor V114 is conserved across neuraminidase subtypes. Furthermore, Y155 is not conserved even among avian and swine N1 viruses. Structurally, both residues reside far from the neuraminidase active site. D225 forms part of the receptor binding site of the haemagglutinin. We believe this is the first demonstration of a specific haemagglutinin mutation correlating with reduced drug susceptibility in plaque assays in both Madin Darby Canine Kidney and SIAT cells. PMID:23759505

  10. Insertion of a multibasic cleavage site in the haemagglutinin of human influenza H3N2 virus does not increase pathogenicity in ferrets

    PubMed Central

    Schrauwen, Eefje J. A.; Bestebroer, Theo M.; Munster, Vincent J.; de Wit, Emmie; Herfst, Sander; Rimmelzwaan, Guus F.; Osterhaus, Albert D. M. E.

    2011-01-01

    A multibasic cleavage site (MBCS) in the haemagglutinin (HA) protein of influenza A virus is a key determinant of pathogenicity in chickens, and distinguishes highly pathogenic avian influenza (HPAI) viruses from low pathogenic avian influenza viruses (LPAI). An MBCS has only been detected in viruses of the H5 and H7 subtypes. Here we investigated the phenotype of a human H3N2 virus with an MBCS in HA. Insertion of an MBCS in the H3N2 virus resulted in cleavage of HA and efficient replication in Madin–Darby canine kidney cells in the absence of exogenous trypsin in vitro, similar to HPAI H5N1 virus. However, studies in ferrets demonstrated that insertion of the MBCS into HA did not result in increased virus shedding, cellular host range, systemic replication or pathogenicity, as compared with wild-type virus. This study indicates that acquisition of an MBCS alone is insufficient to increase pathogenicity of a prototypical seasonal human H3N2 virus. PMID:21346026

  11. Inactivation of influenza virus haemagglutinin by chlorine dioxide: oxidation of the conserved tryptophan 153 residue in the receptor-binding site.

    PubMed

    Ogata, Norio

    2012-12-01

    Airborne influenza virus infection of mice can be prevented by gaseous chlorine dioxide (ClO(2)). This study demonstrated that ClO(2) abolished the function of the haemagglutinin (HA) of influenza A virus (H1N1) in a concentration-, time- and temperature-dependent manner. The IC(50) during a 2 min reaction with ClO(2) at 25 °C was 13.7 µM, and the half-life time of HA with 100 µM ClO(2) at 25 °C was 19.5 s. Peptides generated from a tryptic digest of ClO(2)-treated virus were analysed by mass spectrometry. An HA fragment, (150)NLLWLTGK(157) was identified in which the tryptophan residue (W153) was 32 mass units greater than expected. The W153 residue of this peptide, which is derived from the central region of the receptor-binding site of HA, is highly conserved. It was shown that W153 was oxidized to N-formylkynurenine in ClO(2)-treated virus. It was concluded that the inactivation of influenza virus by ClO(2) is caused by oxidation of W153 in HA, thereby abolishing its receptor-binding ability. PMID:22933663

  12. Permissible variation in the 3' non-coding region of the haemagglutinin genome segment of the H5N1 candidate influenza vaccine virus NIBRG-14 [corrected].

    PubMed

    Johnson, Rachel E; Hamill, Michelle; Harvey, Ruth; Nicolson, Carolyn; Robertson, James S; Engelhardt, Othmar G

    2012-01-01

    The candidate H5N1 vaccine virus NIBRG-14 was created in response to a call from the World Health Organisation in 2004 to prepare candidate vaccine viruses (CVVs) to combat the threat of an H5N1 pandemic. NIBRG-14 was created by reverse genetics and is composed of the neuraminidase (NA) and modified haemagglutinin (HA) genes from A/Vietnam/1194/2004 and the internal genes of PR8, a high growing laboratory adapted influenza A(H1N1) strain. Due to time constraints, the non-coding regions (NCRs) of A/Vietnam/1194/2004 HA were not determined prior to creating NIBRG-14. Consequently, the sequence of the primers used to clone the modified A/Vietnam/1194/2004 HA was based upon previous experience of cloning H5N1 viruses. We report here that the HA 3' NCR sequence of NIBRG-14 is different to that of the parental wild type virus A/Vietnam/1194/2004; however this does not appear to impact on its growth or antigen yield. We introduced additional small changes into the 3'NCR of NIBRG-14; these had only minor effects on viral growth and antigen content. These findings may serve to assure the influenza vaccine community that generation of CVVs using best-guess NCR sequences, based on sequence alignments, are likely to produce robust viruses. PMID:22606247

  13. Sequence and phylogenetic analysis of the haemagglutinin genes of H9N2 avian influenza viruses isolated from commercial chickens in Iran.

    PubMed

    Homayounimehr, Ali Reza; Dadras, Habibollah; Shoushtari, Abdolhamid; Pourbakhsh, Seyyed Ali

    2010-08-01

    To determine the genetic relationship of Iranian viruses, the haemagglutinin (HA) genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 1998-2002 were amplified and sequenced. Sequence analysis and phylogenetic studies were conducted by comparing each isolate with those of the available H9N2 strains at GenBank. All these ten isolates had the same sequence -R-S-S-R/G-L- of proteolytic cleavage site of the HA. Nucleotide sequence comparisons of HA gene from Iranian isolates showed 95.2-99.1% identity within the group. Five isolates had leucine (L) at position 226 instead of glutamine (Q). Phylogenetic analysis showed that all our isolates belonged to the G1-like sublineage. Also these isolates showed some degree of homology with other H9N2 isolates e.g., 94.3-96.9% with qu/HK/G1/97, 96.1-98.6% with pa/Chiba/1/97, 95.6-98.2% with pa/Narita/92A/98, and 94.0-96.3% with HK/1073/99. On the basis of phylogenetic and molecular characterization evidence, we concluded that the H9N2 subtype influenza viruses circulating in chicken flocks in Iran since 1998-2002 had a common origin. The results of this study indicated that all Iranian viruses have the potential to emerge as highly pathogenic influenza virus, and considering the homology of these isolates with human H9N2 strains, it seems that the potential of these avian influenza isolates to infect human should not be overlooked. PMID:20390351

  14. H5N1 influenza A virus with K193E and G225E double mutations in haemagglutinin is attenuated and immunogenic in mice.

    PubMed

    Han, Peng-Fei; Li, Jing; Hu, Yi; Sun, Wei; Zhang, Sen; Yang, Yin-Hui; Li, Yu-Chang; Kang, Xiao-Ping; Wu, Xiao-Yan; Zhu, Shun-Ya; Zhang, Yu; Zhu, Qing-Yu; Qin, Cheng-Feng; Jiang, Tao

    2015-09-01

    Live-attenuated influenza vaccines (LAIVs) are now available for the prevention of influenza, with LAIV strains generally derived from serial passage in cultures or by reverse genetics (RG). The receptor-binding domain (RBD) in haemagglutinin (HA) of influenza virus is responsible for viral binding to the avian-type 2,3-α-linked or human-type 2,6-α-linked sialic acid receptor; however, the virulence determinants in the RBD of H5N1 virus remain largely unknown. In the present study, serial passage of H5N1 virus A/Vietnam/1194/2004 in Madin-Darby canine kidney cells resulted in the generation of adapted variants with large-plaque morphology, and genomic sequencing of selected variants revealed two specific amino acid substitutions (K193E and G225E) in the RBD. RG was used to generate H5N1 viruses containing either single or double substitutions in HA. The RG virus containing K193E and G225E mutations (rVN-K193E/G225E) demonstrated large-plaque morphology, enhanced replication and genetic stability after serial passage, without changing the receptor-binding preference. Importantly, in vivo virulence assessment demonstrated that rVN-K193E/G225E was significantly attenuated in mice. Microneutralization and haemagglutination inhibition assays demonstrated that immunization with rVN-K193E/G225E efficiently induced a robust antibody response against WT H5N1 virus in mice. Taken together, our experiments demonstrated that K193E and G225E mutations synergistically attenuated H5N1 virus without enhancing the receptor-binding avidity, and that the RG virus rVN-K193E/G225E represents a potential H5N1 LAIV strategy that deserves further development. These findings identify the RBD as a novel attenuation target for live vaccine development and highlight the complexity of RBD interactions. PMID:25998916

  15. A potent broad-spectrum protective human monoclonal antibody crosslinking two haemagglutinin monomers of influenza A virus

    PubMed Central

    Wu, Ying; Cho, MyungSam; Shore, David; Song, Manki; Choi, JungAh; Jiang, Tao; Deng, Yong-Qiang; Bourgeois, Melissa; Almli, Lynn; Yang, Hua; Chen, Li-Mei; Shi, Yi; Qi, Jianxu; Li, An; Yi, Kye Sook; Chang, MinSeok; Bae, Jin Soo; Lee, HyunJoo; Shin, JiYoung; Stevens, James; Hong, SeoungSuh; Qin, Cheng-Feng; Gao, George F.; Chang, Shin Jae; Donis, Ruben O.

    2015-01-01

    Effective annual influenza vaccination requires frequent changes in vaccine composition due to both antigenic shift for different subtype hemagglutinins (HAs) and antigenic drift in a particular HA. Here we present a broadly neutralizing human monoclonal antibody with an unusual binding modality. The antibody, designated CT149, was isolated from convalescent patients infected with pandemic H1N1 in 2009. CT149 is found to neutralize all tested group 2 and some group 1 influenza A viruses by inhibiting low pH-induced, HA-mediated membrane fusion. It promotes killing of infected cells by Fc-mediated antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. X-ray crystallographic data reveal that CT149 binds primarily to the fusion domain in HA2, and the light chain is also largely involved in binding. The epitope recognized by this antibody comprises amino-acid residues from two adjacent protomers of HA. This binding characteristic of CT149 will provide more information to support the design of more potent influenza vaccines. PMID:26196962

  16. Cloning and identification of the infectious salmon anaemia virus haemagglutinin.

    PubMed

    Krossøy, B; Devold, M; Sanders, L; Knappskog, P M; Aspehaug, V; Falk, K; Nylund, A; Koumans, S; Endresen, C; Biering, E

    2001-07-01

    Infectious salmon anaemia virus (ISAV) is an orthomyxo-like virus that causes serious disease in Atlantic salmon (Salmo salar). Like the orthomyxoviruses, ISAV has been shown to possess haemagglutinin (HA) activity. This study presents the cloning, expression and identification of the ISAV HA gene, which was isolated from a cDNA library by immunoscreening. The HA gene contained an ISAV-specific conserved nucleotide motif in the 5' region and a 1167 bp open reading frame encoding a protein with a predicted molecular mass of 42.4 kDa. The HA gene was expressed in a baculovirus system. A monoclonal antibody (MAb) shown previously to be directed against the ISAV HA reacted with insect cells infected with recombinant baculovirus. Salmon erythrocytes also adsorbed to these cells and adsorption was inhibited by the addition of either the ISAV-specific MAb or a polyclonal rabbit serum prepared against purified virus, confirming the virus specificity of the reaction. Immunoblot analyses indicated that ISAV HA, in contrast to influenza virus HA, is not posttranslationally cleaved. Sequence comparisons of the HA gene from five Norwegian, one Scottish and one Canadian isolate revealed a highly polymorphic region that may be useful in epidemiological studies. PMID:11413388

  17. Sialic acid receptor specificity on erythrocytes affects detection of antibody to avian influenza haemagglutinin.

    PubMed

    Stephenson, I; Wood, J M; Nicholson, K G; Zambon, M C

    2003-07-01

    Haemagglutination-inhibition tests (HI) are used to detect increases in influenza antibody in serum. However, they are relatively insensitive for the detection of human antibody responses to avian haemagglutinin, even in the presence of high titres of neutralising antibody after confirmed infection or vaccination. Human influenza viruses bind preferentially sialic acid containing N-acetylneuraminic acid alpha2,6-galactose (SAalpha2,6Gal) linkages while avian and equine viruses bind preferentially those containing N-acetylneuraminic acid alpha2,3-galactose (SAalpha2,3Gal) linkages. Increasing the proportion of SAalpha2,3Gal linkages on the erythrocytes used, by enzymatic modification or change of species, improves the ability of erythrocytes to bind to avian influenza strains and thereby improves the sensitivity of detection of antibody to avian and equine HA in a range of mammalian and human sera using HI tests. PMID:12767002

  18. Avirulent Marek’s Disease Virus Type 1 Strain 814 Vectored Vaccine Expressing Avian Influenza (AI) Virus H5 Haemagglutinin Induced Better Protection Than Turkey Herpesvirus Vectored AI Vaccine

    PubMed Central

    Cui, Xianlan; Zhao, Yan; Shi, Xingming; Li, Qiaoling; Yan, Shuai; Gao, Ming; Wang, Mei; Liu, Changjun; Wang, Yunfeng

    2013-01-01

    Background Herpesvirus of turkey (HVT) as a vector to express the haemagglutinin (HA) of avian influenza virus (AIV) H5 was developed and its protection against lethal Marek’s disease virus (MDV) and highly pathogenic AIV (HPAIV) challenges was evaluated previously. It is well-known that avirulemt MDV type 1 vaccines are more effective than HVT in prevention of lethal MDV infection. To further increase protective efficacy against HPAIV and lethal MDV, a recombinant MDV type 1 strain 814 was developed to express HA gene of HPAIV H5N1. Methodology/Principal Findings A recombinant MDV-1 strain 814 expressing HA gene of HPAIV H5N1 virus A/goose/Guangdong/3/96 at the US2 site (rMDV-HA) was developed under the control of a human CMV immediate-early promoter. The HA expression in the rMDV-HA was tested by immunofluorescence and Western blot analyses, and in vitro and in vivo growth properties of rMDV-HA were also analyzed. Furthermore, we evaluated and compared the protective immunity of rMDV-HA and previously constructed rHVT-HA against HPAIV and lethal MDV. Vaccination of chickens with rMDV-HA induced 80% protection against HPAIV, which was better than the protection rate by rHVT-HA (66.7%). In the animal study with MDV challenge, chickens immunized with rMDV-HA were completely protected against virulent MDV strain J-1 whereas rHVT-HA only induced 80% protection with the same challenge dose. Conclusions/Significance The rMDV-HA vaccine was more effective than rHVT-HA vaccine for protection against lethal MDV and HPAIV challenges. Therefore, avirulent MDV type 1 vaccine is a better vector than HVT for development of a recombinant live virus vaccine against virulent MDV and HPAIV in poultry. PMID:23301062

  19. Putative suppressing effect of IgG Fc-conjugated haemagglutinin (HA) stalk of influenza virus H7N9 on the neutralizing immunogenicity of Fc-conjugated HA head: implication for rational design of HA-based influenza vaccines.

    PubMed

    He, B; Xia, S; Yu, F; Fu, Y; Li, W; Wang, Q; Lu, L; Jiang, S

    2016-02-01

    The emergence of influenza A H7N9 in infection has posed a great threat to public health globally. Poor immunogenicity of H7N9 haemagglutinin (HA) is a major obstacle to the development of an effective H7N9 vaccine. Here, we found that the vaccine containing the H7HA head conjugated with IgG Fc (Hd-Fc) induced strong neutralizing antibody responses and protection against H7N9 infection, whilst the Fc-conjugated H7HA stalk (St-Fc)-based vaccine could not induce neutralizing antibodies, although the St-Fc-immunized mice were partially protected. The vaccines containing the full-length extracellular domain of HA conjugated with Fc and the mixture of Hd-Fc plus St-Fc induced significantly lower neutralizing antibody and haemagglutination inhibition titres than the Hd-Fc-based vaccine. These results suggest that the St-Fc may have inhibitory effects on the neutralizing immunogenicity of Hd-Fc. Therefore, the neutralizing domain(s), such as the receptor-binding domain, in the HA head should be kept and the non-neutralizing domain(s) in the HA stalk with the ability to potentially suppress the neutralizing immunogenicity of HA head should be removed from Fc-conjugated HA-based influenza vaccines to increase the neutralizing antibody response. PMID:26653217

  20. CD71 targeting boosts immunogenicity of sublingually delivered influenza haemagglutinin antigen and protects against viral challenge in mice.

    PubMed

    Mann, Jamie F S; Tregoning, John S; Aldon, Yoann; Shattock, Robin J; McKay, Paul F

    2016-06-28

    The delivery of vaccines to the sublingual mucosa is an attractive prospect due to the ease and acceptability of such an approach. However, novel adjuvant and delivery approaches are required to optimally vaccinate at this site. We have previously shown that conjugation of protein antigen to the iron transport molecule, transferrin, can significantly enhance mucosal immune responses. We tested whether conjugating influenza haemagglutinin to transferrin could improve the immune response to sublingually delivered antigen. Transferrin conjugated haemagglutinin induced a significant antibody and T cell response in both naïve animals and previously immunized animals. The immune response generated was able to protect mice against influenza virus challenge. Sublingually administered antigen dispersed more widely through the gastro-intestinal tract than intranasally delivered antigen and transferrin conjugation had a more marked effect on sublingually delivered antigen than intranasal immunisation. From these studies we conclude that transferrin conjugation of antigen is effective at boosting immune responses to sublingually delivered antigen and may be an attractive approach for influenza vaccines, particularly when mass campaigns are required. PMID:27094605

  1. Molecular pathogenesis of H5 highly pathogenic avian influenza: the role of the haemagglutinin cleavage site motif.

    PubMed

    Luczo, Jasmina M; Stambas, John; Durr, Peter A; Michalski, Wojtek P; Bingham, John

    2015-11-01

    The emergence of H5N1 highly pathogenic avian influenza has caused a heavy socio-economic burden through culling of poultry to minimise human and livestock infection. Although human infections with H5N1 have to date been limited, concerns for the pandemic potential of this zoonotic virus have been greatly intensified following experimental evidence of aerosol transmission of H5N1 viruses in a mammalian infection model. In this review, we discuss the dominance of the haemagglutinin cleavage site motif as a pathogenicity determinant, the host-pathogen molecular interactions driving cleavage activation, reverse genetics manipulations and identification of residues key to haemagglutinin cleavage site functionality and the mechanisms of cell and tissue damage during H5N1 infection. We specifically focus on the disease in chickens, as it is in this species that high pathogenicity frequently evolves and from which transmission to the human population occurs. With >75% of emerging infectious diseases being of zoonotic origin, it is necessary to understand pathogenesis in the primary host to explain spillover events into the human population. PMID:26467906

  2. Molecular evolution of haemagglutinin (H) gene in measles virus.

    PubMed

    Kimura, Hirokazu; Saitoh, Mika; Kobayashi, Miho; Ishii, Haruyuki; Saraya, Takeshi; Kurai, Daisuke; Tsukagoshi, Hiroyuki; Shirabe, Komei; Nishina, Atsuyoshi; Kozawa, Kunihisa; Kuroda, Makoto; Takeuchi, Fumihiko; Sekizuka, Tsuyoshi; Minakami, Hisanori; Ryo, Akihide; Takeda, Makoto

    2015-01-01

    We studied the molecular evolution of the haemagglutinin (H) gene (full length) in all genotypes (24 genotypes, 297 strains) of measles virus (MeV). The gene's evolutionary timescale was estimated by the Bayesian Markov chain Monte Carlo (MCMC) method. We also analysed positive selection sites. The MCMC tree indicated that the MeV H gene diverged from the rinderpest virus (same genus) about 250 years ago and that 24 MeV genotypes formed 3 lineages dating back to a 1915 ancestor (95% highest posterior density [HPD] 1882-1941) with relatively rapid evolution (mean rate: 9.02 × 10(-4) substitutions/site/year). The 3 lineages diverged in 1915 (lineage 1, 95% HPD 1882-1941), 1954 (lineage 2, 95% HPD 1937-1969), and 1940 (lineage 3, 95% HPD 1927-1952). These 24 genotypes may have diverged and emerged between the 1940s and 1990 s. Selective pressure analysis identified many negative selection sites on the H protein but only a few positive selection sites, suggesting strongly operated structural and/or functional constraint of changes on the H protein. Based on the molecular evolution of H gene, an ancestor MeV of the 24 genotypes emerged about 100 years ago and the structure of H protein has been well conserved. PMID:26130388

  3. A broadly neutralizing anti-influenza antibody reveals ongoing capacity of haemagglutinin-specific memory B cells to evolve.

    PubMed

    Fu, Ying; Zhang, Zhen; Sheehan, Jared; Avnir, Yuval; Ridenour, Callie; Sachnik, Thomas; Sun, Jiusong; Hossain, M Jaber; Chen, Li-Mei; Zhu, Quan; Donis, Ruben O; Marasco, Wayne A

    2016-01-01

    Understanding the natural evolution and structural changes involved in broadly neutralizing antibody (bnAb) development holds great promise for improving the design of prophylactic influenza vaccines. Here we report an haemagglutinin (HA) stem-directed bnAb, 3I14, isolated from human memory B cells, that utilizes a heavy chain encoded by the IGHV3-30 germline gene. MAb 3I14 binds and neutralizes groups 1 and 2 influenza A viruses and protects mice from lethal challenge. Analysis of VH and VL germline back-mutants reveals binding to H3 and H1 but not H5, which supports the critical role of somatic hypermutation in broadening the bnAb response. Moreover, a single VLD94N mutation improves the affinity of 3I14 to H5 by nearly 10-fold. These data provide evidence that memory B cell evolution can expand the HA subtype specificity. Our results further suggest that establishing an optimized memory B cell pool should be an aim of 'universal' influenza vaccine strategies. PMID:27619409

  4. A genotype network reveals homoplastic cycles of convergent evolution in influenza A (H3N2) haemagglutinin

    PubMed Central

    Wagner, Andreas

    2014-01-01

    Networks of evolving genotypes can be constructed from the worldwide time-resolved genotyping of pathogens like influenza viruses. Such genotype networks are graphs where neighbouring vertices (viral strains) differ in a single nucleotide or amino acid. A rich trove of network analysis methods can help understand the evolutionary dynamics reflected in the structure of these networks. Here, I analyse a genotype network comprising hundreds of influenza A (H3N2) haemagglutinin genes. The network is rife with cycles that reflect non-random parallel or convergent (homoplastic) evolution. These cycles also show patterns of sequence change characteristic for strong and local evolutionary constraints, positive selection and mutation-limited evolution. Such cycles would not be visible on a phylogenetic tree, illustrating that genotype network analysis can complement phylogenetic analyses. The network also shows a distinct modular or community structure that reflects temporal more than spatial proximity of viral strains, where lowly connected bridge strains connect different modules. These and other organizational patterns illustrate that genotype networks can help us study evolution in action at an unprecedented level of resolution. PMID:24827434

  5. A genotype network reveals homoplastic cycles of convergent evolution in influenza A (H3N2) haemagglutinin.

    PubMed

    Wagner, Andreas

    2014-07-01

    Networks of evolving genotypes can be constructed from the worldwide time-resolved genotyping of pathogens like influenza viruses. Such genotype networks are graphs where neighbouring vertices (viral strains) differ in a single nucleotide or amino acid. A rich trove of network analysis methods can help understand the evolutionary dynamics reflected in the structure of these networks. Here, I analyse a genotype network comprising hundreds of influenza A (H3N2) haemagglutinin genes. The network is rife with cycles that reflect non-random parallel or convergent (homoplastic) evolution. These cycles also show patterns of sequence change characteristic for strong and local evolutionary constraints, positive selection and mutation-limited evolution. Such cycles would not be visible on a phylogenetic tree, illustrating that genotype network analysis can complement phylogenetic analyses. The network also shows a distinct modular or community structure that reflects temporal more than spatial proximity of viral strains, where lowly connected bridge strains connect different modules. These and other organizational patterns illustrate that genotype networks can help us study evolution in action at an unprecedented level of resolution. PMID:24827434

  6. [Influenza virus].

    PubMed

    Juozapaitis, Mindaugas; Antoniukas, Linas

    2007-01-01

    Every year, especially during the cold season, many people catch an acute respiratory disease, namely flu. It is easy to catch this disease; therefore, it spreads very rapidly and often becomes an epidemic or a global pandemic. Airway inflammation and other body ailments, which form in a very short period, torment the patient several weeks. After that, the symptoms of the disease usually disappear as quickly as they emerged. The great epidemics of flu have rather unique characteristics; therefore, it is possible to identify descriptions of such epidemics in historic sources. Already in the 4th century bc, Hippocrates himself wrote about one of them. It is known now that flu epidemics emerge rather frequently, but there are no regular intervals between those events. The epidemics can differ in their consequences, but usually they cause an increased mortality of elderly people. The great flu epidemics of the last century took millions of human lives. In 1918-19, during "The Spanish" pandemic of flu, there were around 40-50 millions of deaths all over the world; "Pandemic of Asia" in 1957 took up to one million lives, etc. Influenza virus can cause various disorders of the respiratory system: from mild inflammations of upper airways to acute pneumonia that finally results in the patient's death. Scientist Richard E. Shope, who investigated swine flu in 1920, had a suspicion that the cause of this disease might be a virus. Already in 1933, scientists from the National Institute for Medical Research in London - Wilson Smith, Sir Christopher Andrewes, and Sir Patrick Laidlaw - for the first time isolated the virus, which caused human flu. Then scientific community started the exhaustive research of influenza virus, and the great interest in this virus and its unique features is still active even today. PMID:18182834

  7. 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

  8. Avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. Development of high-yield influenza A virus vaccine viruses.

    PubMed

    Ping, Jihui; Lopes, Tiago J S; Nidom, Chairul A; Ghedin, Elodie; Macken, Catherine A; Fitch, Adam; Imai, Masaki; Maher, Eileen A; Neumann, Gabriele; Kawaoka, Yoshihiro

    2015-01-01

    Vaccination is one of the most cost-effective ways to prevent infection. Influenza vaccines propagated in cultured cells are approved for use in humans, but their yields are often suboptimal. Here, we screened A/Puerto Rico/8/34 (PR8) virus mutant libraries to develop vaccine backbones (defined here as the six viral RNA segments not encoding haemagglutinin and neuraminidase) that support high yield in cell culture. We also tested mutations in the coding and regulatory regions of the virus, and chimeric haemagglutinin and neuraminidase genes. A combination of high-yield mutations from these screens led to a PR8 backbone that improved the titres of H1N1, H3N2, H5N1 and H7N9 vaccine viruses in African green monkey kidney and Madin-Darby canine kidney cells. This PR8 backbone also improves titres in embryonated chicken eggs, a common propagation system for influenza viruses. This PR8 vaccine backbone thus represents an advance in seasonal and pandemic influenza vaccine development. PMID:26334134

  10. Development of high-yield influenza A virus vaccine viruses

    PubMed Central

    Ping, Jihui; Lopes, Tiago J.S.; Nidom, Chairul A.; Ghedin, Elodie; Macken, Catherine A.; Fitch, Adam; Imai, Masaki; Maher, Eileen A.; Neumann, Gabriele; Kawaoka, Yoshihiro

    2015-01-01

    Vaccination is one of the most cost-effective ways to prevent infection. Influenza vaccines propagated in cultured cells are approved for use in humans, but their yields are often suboptimal. Here, we screened A/Puerto Rico/8/34 (PR8) virus mutant libraries to develop vaccine backbones (defined here as the six viral RNA segments not encoding haemagglutinin and neuraminidase) that support high yield in cell culture. We also tested mutations in the coding and regulatory regions of the virus, and chimeric haemagglutinin and neuraminidase genes. A combination of high-yield mutations from these screens led to a PR8 backbone that improved the titres of H1N1, H3N2, H5N1 and H7N9 vaccine viruses in African green monkey kidney and Madin–Darby canine kidney cells. This PR8 backbone also improves titres in embryonated chicken eggs, a common propagation system for influenza viruses. This PR8 vaccine backbone thus represents an advance in seasonal and pandemic influenza vaccine development. PMID:26334134

  11. Avian Influenza Virus and DIVA Strategies.

    PubMed

    Hasan, Noor Haliza; Ignjatovic, Jagoda; Peaston, Anne; Hemmatzadeh, Farhid

    2016-05-01

    Vaccination is becoming a more acceptable option in the effort to eradicate avian influenza viruses (AIV) from commercial poultry, especially in countries where AIV is endemic. The main concern surrounding this option has been the inability of the conventional serological tests to differentiate antibodies produced due to vaccination from antibodies produced in response to virus infection. In attempts to address this issue, at least six strategies have been formulated, aiming to differentiate infected from vaccinated animals (DIVA), namely (i) sentinel birds, (ii) subunit vaccine, (iii) heterologous neuraminidase (NA), (iv) nonstructural 1 (NS1) protein, (v) matrix 2 ectodomain (M2e) protein, and (vi) haemagglutinin subunit 2 (HA2) glycoprotein. This short review briefly discusses the strengths and limitations of these DIVA strategies, together with the feasibility and practicality of the options as a part of the surveillance program directed toward the eventual eradication of AIV from poultry in countries where highly pathogenic avian influenza is endemic. PMID:26900835

  12. INFLUENZA VIRUS IN POULTRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) is normally found in wild birds, particularly in ducks and shorebirds, where it does not cause any perceptible clinical disease. However, poultry, including chickens and turkeys, are not normal hosts for avian influenza, but if the virus is introduced it can result in mi...

  13. Influenza A virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A viruses are important veterinary and human health pathogens around the world. Avian influenza (AI) virus in poultry is unusual in that it can cause a range of disease symptoms from a subclinical infection to being highly virulent with 100% mortality. The difference between low pathogen...

  14. The haemagglutinin protein is an important determinant of measles virus tropism for dendritic cells in vitro.

    PubMed

    Ohgimoto, S; Ohgimoto, K; Niewiesk, S; Klagge, I M; Pfeuffer, J; Johnston, I C; Schneider-Schaulies, J; Weidmann, A; ter Meulen, V; Schneider-Schaulies, S

    2001-08-01

    Recombinant measles viruses (MV) in which the authentic glycoprotein genes encoding the fusion and the haemagglutinin (H) proteins of the Edmonston (ED) vaccine strains were swapped singly or doubly for the corresponding genes of a lymphotropic MV wild-type virus (strain WTF) were used previously to investigate MV tropism in cell lines in tissue culture. When these recombinants and their parental strains, the molecular ED-based clone (ED-tag) and WTF, were used to infect cotton rats, only viruses expressing the MV WTF H protein replicated in secondary lymphatic tissues and caused significant immunosuppression. In vitro, viruses containing the ED H protein revealed a tropism for human peripheral blood lymphocytes as documented by enhanced binding and virus production, whereas those containing the WTF H protein replicated well in monocyte-derived dendritic cells (Mo-DC). This did not correlate with more efficient binding of these viruses to DC, but with an enhancement of uptake, virus spread, accumulation of viral antigens and virus production. Thus, replacement of the ED H protein with WTF H protein was sufficient to confer the DC tropism of WTF to ED-tag in vitro. This study suggests that the MV H protein plays an important role in determining cell tropism to immune cells and this may play an important role in the induction of immunosuppression in vivo. PMID:11457989

  15. A PCR based method for the identification of equine influenza virus from clinical samples.

    PubMed

    Oxburgh, L; Hagström, A

    1999-06-30

    In this paper we describe the development of a nested RT-PCR assay for the rapid diagnosis and characterisation of influenza virus directly from clinical specimens. Viral RNA is extracted from nasal swabs by the guanidine thiocyanate extraction method, and subsequently reverse transcribed. The complementary DNA is then used as template in a nested PCR reaction. Primers designed for use in this assay are specific for three templates; (1) the nucleoprotein (NP) gene, (2) the haemagglutinin gene of the H7N7 equine influenza virus (A1), and (3) the haemagglutinin gene of the H3N8 equine influenza virus (A2). We show that the assays are specific for the target genes chosen, and display sensitivity similar to virus isolation. The NP assay detects a variety of different influenza subtypes, whereas A1 and A2 assays are specific for influenza subtypes H7N7 and H3N8, respectively. Sequencing of amplicons obtained in the A2 assay yields information on antigenic regions of the haemagglutinin molecule, and use of this procedure in the routine surveillance of equine influenza will enable tentative characterisation of circulating viruses despite difficulties in isolating field strains of the H3N8 subtype. The A1 assay will be useful in ascertaining whether viruses of the H7N7 subtype still circulate amongst horses, or whether these are extinct. PMID:10418871

  16. The appearance of H3 influenza viruses in seals.

    PubMed

    Callan, R J; Early, G; Kida, H; Hinshaw, V S

    1995-01-01

    Surveillance for influenza A virus infection of seals has continued following the association of influenza A virus with epizootics of pneumonia in seals off the New England coast in 1979-1980 and 1982-1983. In January 1991 and January to February 1992, influenza A viruses were isolated from seals that died of pneumonia along the Cape Cod peninsula of Massachusetts. Antigenic characterization identified two H4N6 and three H3N3 viruses. This was the first isolation of H3 influenza viruses from seals, although this subtype is frequently detected in birds, pigs, horses and humans. Haemagglutination inhibition assays of the H3 isolates showed two distinct antigenic reactivity patterns: one more similar to an avian reference virus (A/Duck/Ukraine/1/63) and one more similar to a human virus (A/Aichi/2/68). The haemagglutinin (HA) genes from two of the H3 seal viruses showing different antigenic reactivity (A/Seal/MA/3911/92 and A/Seal/MA/3984/92) were 99.7% identical, with four nucleotide differences accounting for four amino acid differences. Phylogenetic analysis demonstrated that both of these sequences were closely related to the sequence from the avian H3 virus, A/Mallard/New York/6874/78. This indicates that influenza A viruses of apparent avian origin, including the H3 subtype viruses, continue to infect seals. PMID:7844533

  17. Human Influenza Virus Infections.

    PubMed

    Peteranderl, Christin; Herold, Susanne; Schmoldt, Carole

    2016-08-01

    Seasonal and pandemic influenza are the two faces of respiratory infections caused by influenza viruses in humans. As seasonal influenza occurs on an annual basis, the circulating virus strains are closely monitored and a yearly updated vaccination is provided, especially to identified risk populations. Nonetheless, influenza virus infection may result in pneumonia and acute respiratory failure, frequently complicated by bacterial coinfection. Pandemics are, in contrary, unexpected rare events related to the emergence of a reassorted human-pathogenic influenza A virus (IAV) strains that often causes increased morbidity and spreads extremely rapidly in the immunologically naive human population, with huge clinical and economic impact. Accordingly, particular efforts are made to advance our knowledge on the disease biology and pathology and recent studies have brought new insights into IAV adaptation mechanisms to the human host, as well as into the key players in disease pathogenesis on the host side. Current antiviral strategies are only efficient at the early stages of the disease and are challenged by the genomic instability of the virus, highlighting the need for novel antiviral therapies targeting the pulmonary host response to improve viral clearance, reduce the risk of bacterial coinfection, and prevent or attenuate acute lung injury. This review article summarizes our current knowledge on the molecular basis of influenza infection and disease progression, the key players in pathogenesis driving severe disease and progression to lung failure, as well as available and envisioned prevention and treatment strategies against influenza virus infection. PMID:27486731

  18. Recent zoonoses caused by influenza A viruses.

    PubMed

    Alexander, D J; Brown, I H

    2000-04-01

    Influenza is a highly contagious, acute illness which has afflicted humans and animals since ancient times. Influenza viruses are part of the Orthomyxoviridae family and are grouped into types A, B and C according to antigenic characteristics of the core proteins. Influenza A viruses infect a large variety of animal species, including humans, pigs, horses, sea mammals and birds, occasionally producing devastating pandemics in humans, such as in 1918, when over twenty million deaths occurred world-wide. The two surface glycoproteins of the virus, haemagglutinin (HA) and neuraminidase (NA), are the most important antigens for inducing protective immunity in the host and therefore show the greatest variation. For influenza A viruses, fifteen antigenically distinct HA subtypes and nine NA subtypes are recognised at present; a virus possesses one HA and one NA subtype, apparently in any combination. Although viruses of relatively few subtype combinations have been isolated from mammalian species, all subtypes, in most combinations, have been isolated from birds. In the 20th Century, the sudden emergence of antigenically different strains in humans, termed antigenic shift, has occurred on four occasions, as follows, in 1918 (H1N1), 1957 (H2N2), 1968 (H3N2) and 1977 (H1N1), each resulting in a pandemic. Frequent epidemics have occurred between the pandemics as a result of gradual antigenic change in the prevalent virus, termed antigenic drift. Currently, epidemics occur throughout the world in the human population due to infection with influenza A viruses of subtypes H1N1 and H3N2 or with influenza B virus. The impact of these epidemics is most effectively measured by monitoring excess mortality due to pneumonia and influenza. Phylogenetic studies suggest that aquatic birds could be the source of all influenza A viruses in other species. Human pandemic strains are thought to have emerged through one of the following three mechanisms: genetic reassortment (occurring as a

  19. Selection of antigenically advanced variants of seasonal influenza viruses.

    PubMed

    Li, Chengjun; Hatta, Masato; Burke, David F; Ping, Jihui; Zhang, Ying; Ozawa, Makoto; Taft, Andrew S; Das, Subash C; Hanson, Anthony P; Song, Jiasheng; Imai, Masaki; Wilker, Peter R; Watanabe, Tokiko; Watanabe, Shinji; Ito, Mutsumi; Iwatsuki-Horimoto, Kiyoko; Russell, Colin A; James, Sarah L; Skepner, Eugene; Maher, Eileen A; Neumann, Gabriele; Klimov, Alexander I; Kelso, Anne; McCauley, John; Wang, Dayan; Shu, Yuelong; Odagiri, Takato; Tashiro, Masato; Xu, Xiyan; Wentworth, David E; Katz, Jacqueline M; Cox, Nancy J; Smith, Derek J; Kawaoka, Yoshihiro

    2016-01-01

    Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent sera to human H1N1 and H3N2 viruses. We also selected antigenic escape variants from human viruses treated with convalescent sera and from mice that had been previously immunized against human influenza viruses. Our pilot studies with past influenza viruses identified escape mutants that were antigenically similar to variants that emerged in nature, establishing the feasibility of our approach. Our studies with contemporary human influenza viruses identified escape mutants before they caused an epidemic in 2014-2015. This approach may aid in the prediction of potential antigenic escape variants and the selection of future vaccine candidates before they become widespread in nature. PMID:27572841

  20. Swine Influenza/Variant Influenza Viruses

    MedlinePlus

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

  1. Characterization of A/eq-1 virus isolated during the equine influenza epidemic in India.

    PubMed

    Singh, G

    1994-02-01

    The equine influenza virus, Ludhiana/5/87, isolated from the clinical material during the epidemic of equine influenza in India in 1987 was inhibited in haemagglutination-inhibition test by the antiserum against the prototype A/eq/Prague/1/56 (H7N7) virus and by post-epidemic horse sera. In haemagglutinin and neuraminidase analysis, the A/eq/Ludhiana/5/87 isolate appeared similar to the prototype A/eq/Prague/1/56 virus and was characterized as the H7N7 subtype. PMID:8067310

  2. 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

  3. Pathobiology of avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus causes serious disease in a wide variety of birds and mammals. Its natural hosts are wild aquatic birds, in which most infections are unapparent. Avian Influenza (AI) viruses are classified into 16 hemagglutinin (H1-16) and nine neuraminidase (N1-9) subtypes. Each virus has on...

  4. Avian influenza A viruses of southern China and Hong Kong: ecological aspects and implications for man*

    PubMed Central

    Shortridge, K. F.

    1982-01-01

    Continuous surveillance of the influenza viruses isolated from domestic poultry from southern China and Hong Kong over more than 4 years resulted in the isolation of influenza viruses possessing 46 different combinations of haemagglutinin (H) and neuraminidase (N) subtypes. Of these, 43 were obtained from ducks from China. In all cases, infection appeared to be asymptomatic. The antigenic combination found most commonly in the viruses isolated was H4N6, which accounted for approximately one-quarter of the duck isolates, its occurrence being more frequent than expected from a statistical analysis of the observed frequencies of the haemagglutinin and neuraminidase genes among all the isolates. Some combinations of H and N occurred less frequently than expected or not at all. Influenza viruses tended to be isolated more frequently from ducks during the summer months in comparison with paramyxoviruses, which were more commonly encountered in the winter. Possible reasons for the great antigenic diversity of influenza A viruses in the poultry, especially the ducks, in the region are discussed together with the potential significance of these viruses to the emergence of human influenza pandemics. PMID:6979416

  5. Melaleuca alternifolia concentrate inhibits in vitro entry of influenza virus into host cells.

    PubMed

    Li, Xinghua; Duan, Songwei; Chu, Cordia; Xu, Jun; Zeng, Gucheng; Lam, Alfred King-Yin; Zhou, Junmei; Yin, Yue; Fang, Danyun; Reynolds, Maxwell John; Gu, Huaiyu; Jiang, Lifang

    2013-01-01

    Influenza virus causes high morbidity among the infected population annually and occasionally the spread of pandemics. Melaleuca alternifolia Concentrate (MAC) is an essential oil derived from a native Australian tea tree. Our aim was to investigate whether MAC has any in vitro inhibitory effect on influenza virus infection and what mechanism does the MAC use to fight the virus infection. In this study, the antiviral activity of MAC was examined by its inhibition of cytopathic effects. In silico prediction was performed to evaluate the interaction between MAC and the viral haemagglutinin. We found that when the influenza virus was incubated with 0.010% MAC for one hour, no cytopathic effect on MDCK cells was found after the virus infection and no immunofluorescence signal was detected in the host cells. Electron microscopy showed that the virus treated with MAC retained its structural integrity. By computational simulations, we found that terpinen-4-ol, which is the major bioactive component of MAC, could combine with the membrane fusion site of haemagglutinin. Thus, we proved that MAC could prevent influenza virus from entering the host cells by disturbing the normal viral membrane fusion procedure. PMID:23966077

  6. Influenza virus surveillance in Argentina during the 2012 season: antigenic characterization, genetic analysis and antiviral susceptibility.

    PubMed

    Benedetti, E; Daniels, R S; Pontoriero, A; Russo, M; Avaro, M; Czech, A; Campos, A; Periolo, N; Gregory, V; McCauley, J W; Baumeister, E G

    2016-03-01

    The activity and circulation of influenza viruses in Argentina was studied during 2012 as part of the Argentinean Surveillance for Influenza and other Respiratory Viruses, in the context of Global Influenza Surveillance. The antigenicity and molecular characteristics of haemagglutinins (HA) of circulating influenza A and B viruses were analysed to assess the emergence of virus variants. Susceptibility to oseltamivir and zanamivir was evaluated by enzymatic assay and results were backed-up by sequencing of the neuraminidase (NA) genes. During the 2012 season, influenza virus circulation in Argentina was detected from weeks 24 to 51. The HA sequences of the studied A(H1N1)pdm09 subtype viruses segregated in a different genetic group compared to those identified during the 2009 pandemic, although they were still closely related antigenically to the vaccine virus A/California/07/2009. The HA sequences of the A(H3N2) viruses analysed fell into the A/Victoria/208/2009 clade, genetic group 3C. A mixed circulation of virus variants belonging to B/Victoria and B/Yamagata lineages was detected, with B/Victoria being dominant. All viruses tested were sensitive to oseltamivir and zanamivir except one. This isolate, an A(H1N1)pdm09 virus possessing the substitution NA-N295S, showed highly reduced inhibition by oseltamivir and reduced inhibition by zanamivir. Virological and epidemiological surveillance remains critical for detection of evolving influenza viruses. PMID:26345289

  7. Antigenicity and immunogenicity of experimental equine influenza ISCOM vaccines.

    PubMed

    Mumford, J A; Jessett, D; Dunleavy, U; Wood, J; Hannant, D; Sundquist, B; Cook, R F

    1994-07-01

    A comparison of the antigenicity and immunogenicity of ISCOM vaccines prepared from equine influenza viruses H3N8 and H7N7 was made with inactivated whole-virus vaccines containing equivalent amounts of virus haemagglutinin. ISCOMs stimulated superior antibody responses in terms of both amount and duration. As with conventional whole-virus vaccines, the levels of antibody to virus haemagglutinin induced by ISCOMs correlated with protection. PMID:7975864

  8. Measles viruses of genotype H1 evade recognition by vaccine-induced neutralizing antibodies targeting the linear haemagglutinin noose epitope.

    PubMed

    Finsterbusch, Tim; Wolbert, Anne; Deitemeier, Ingrid; Meyer, Kerstin; Mosquera, Maria Mar; Mankertz, Annette; Santibanez, Sabine

    2009-11-01

    The linear haemagglutinin noose epitope (HNE; aa 379-410) is a protective B-cell epitope and considered to be highly conserved in both the vaccine and the wild-type measles virus (MeV) haemagglutinin (H) proteins. Vaccine virus-derived monoclonal antibodies (mAbs) BH6 and BH216, which target the HNE, neutralized MeVs of genotypes B3, C2, D4, D5, D6, D7 and D8, and the vaccine strain Edmonston Zagreb. In the case of genotype H1, only strain Berlin.DEU/44.01 was neutralized by these mAbs, whereas strains Shenyang.CHN/22.99 and Sofia.BGR/19.05 were not. The H gene sequences of these two strains showed an exchange of proline 397 (P397) to leucine (L397). Mutated H proteins, with P397 exchanged to L and vice versa, were compared with original H proteins by indirect fluorescence assay. H proteins exhibiting P397 but not those with L397 were recognized by BH6 and BH216. This indicates that L397 leads to the loss of the neutralizing HNE. In contrast, human sera obtained from vaccinees (n=10) did not discriminate between genotype H1 variants P397 and L397. This concurs with the epidemiological observation that the live-attenuated vaccine protects against both H1 variants. Furthermore, we demonstrated that MeVs of genotype H1 also lack the neutralizing epitopes defined by the vaccine virus-induced mAbs BH15, BH125 and BH47. The loss of several neutralizing epitopes, as shown for H1 viruses currently circulating endemically in Asia, implies that epitope monitoring should be considered to be included in measles surveillance. PMID:19625457

  9. Novel vaccines against influenza viruses

    PubMed Central

    Kang, Sang-Moo; Song, Jae-Min; Compans, Richard W.

    2011-01-01

    Killed and live attenuated influenza virus vaccines are effective in preventing and curbing the spread of influenza epidemics when the strains present in the vaccines are closely matched with the predicted epidemic strains. These vaccines are primarily targeted to induce immunity to the variable major target antigen, hemagglutinin (HA) of influenza virus. However, current vaccines are not effective in preventing the emergence of new pandemic or highly virulent viruses. New approaches are being investigated to develop universal influenza virus vaccines as well as to apply more effective vaccine delivery methods. Conserved vaccine targets including the influenza M2 ion channel protein and HA stalk domains are being developed using recombinant technologies to improve the level of cross protection. In addition, recent studies provide evidence that vaccine supplements can provide avenues to further improve current vaccination. PMID:21968298

  10. Emergence of influenza A viruses.

    PubMed Central

    Webby, R J; Webster, R G

    2001-01-01

    Pandemic influenza in humans is a zoonotic disease caused by the transfer of influenza A viruses or virus gene segments from animal reservoirs. Influenza A viruses have been isolated from avian and mammalian hosts, although the primary reservoirs are the aquatic bird populations of the world. In the aquatic birds, influenza is asymptomatic, and the viruses are in evolutionary stasis. The aquatic bird viruses do not replicate well in humans, and these viruses need to reassort or adapt in an intermediate host before they emerge in human populations. Pigs can serve as a host for avian and human viruses and are logical candidates for the role of intermediate host. The transmission of avian H5N1 and H9N2 viruses directly to humans during the late 1990s showed that land-based poultry also can serve between aquatic birds and humans as intermediate hosts of influenza viruses. That these transmission events took place in Hong Kong and China adds further support to the hypothesis that Asia is an epicentre for influenza and stresses the importance of surveillance of pigs and live-bird markets in this area. PMID:11779380

  11. Variant (Swine Origin) Influenza Viruses in Humans

    MedlinePlus

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

  12. Antigenic and genetic evolution of equine H3N8 influenza A viruses.

    PubMed

    Daly, J M; Lai, A C; Binns, M M; Chambers, T M; Barrandeguy, M; Mumford, J A

    1996-04-01

    Evolution of equine influenza a H3N8 viruses was examined by antigenic and genetic analysis of a collection isolates from around the world. It was noted that antigenic and genetic variants of equine H3N8 viruses cocirculate, and in particular that variants currently circulating in Europe and the USA are distinguishable from one another both in terms of antigenic reactivity and genetic structure of the HA1 portion of the haemagglutinin (HA) molecule. Whilst the divergent evolution of American and European isolates may be due to geographical isolation of the two gene pools, some mixing is believed to occur as 'American-like' viruses have been isolated during outbreaks of equine influenza in the UK. The cocirculation of two antigenically and genetically distinct lineages of equine influenza H3N8 viruses has serious implications for vaccine strain selection. PMID:8627254

  13. New aspects of influenza viruses.

    PubMed Central

    Shaw, M W; Arden, N H; Maassab, H F

    1992-01-01

    Influenza virus infections continue to cause substantial morbidity and mortality with a worldwide social and economic impact. The past five years have seen dramatic advances in our understanding of viral replication, evolution, and antigenic variation. Genetic analyses have clarified relationships between human and animal influenza virus strains, demonstrating the potential for the appearance of new pandemic reassortants as hemagglutinin and neuraminidase genes are exchanged in an intermediate host. Clinical trials of candidate live attenuated influenza virus vaccines have shown the cold-adapted reassortants to be a promising alternative to the currently available inactivated virus preparations. Modern molecular techniques have allowed serious consideration of new approaches to the development of antiviral agents and vaccines as the functions of the viral genes and proteins are further elucidated. The development of techniques whereby the genes of influenza viruses can be specifically altered to investigate those functions will undoubtedly accelerate the pace at which our knowledge expands. PMID:1310439

  14. Avian influenza virus RNA extraction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficient extraction and purification of viral RNA is critical for down-stream molecular applications whether it is the sensitive and specific detection of virus in clinical samples, virus gene cloning and expression, or quantification of avian influenza (AI) virus by molecular methods from expe...

  15. Transmission of influenza A viruses.

    PubMed

    Neumann, Gabriele; Kawaoka, Yoshihiro

    2015-05-01

    Influenza A viruses cause respiratory infections that range from asymptomatic to deadly in humans. Widespread outbreaks (pandemics) are attributable to 'novel' viruses that possess a viral hemagglutinin (HA) gene to which humans lack immunity. After a pandemic, these novel viruses form stable virus lineages in humans and circulate until they are replaced by other novel viruses. The factors and mechanisms that facilitate virus transmission among hosts and the establishment of novel lineages are not completely understood, but the HA and basic polymerase 2 (PB2) proteins are thought to play essential roles in these processes by enabling avian influenza viruses to infect mammals and replicate efficiently in their new host. Here, we summarize our current knowledge of the contributions of HA, PB2, and other viral components to virus transmission and the formation of new virus lineages. PMID:25812763

  16. Transmission of Influenza A Viruses

    PubMed Central

    Neumann, Gabriele; Kawaoka, Yoshihiro

    2015-01-01

    Influenza A viruses cause respiratory infections that range from asymptomatic to deadly in humans. Widespread outbreaks (pandemics) are attributable to ‘novel’ viruses that possess a viral hemagglutinin (HA) gene to which humans lack immunity. After a pandemic, these novel viruses form stable virus lineages in humans and circulate until they are replaced by other novel viruses. The factors and mechanisms that facilitate virus transmission among hosts and the establishment of novel lineages are not completely understood, but the HA and basic polymerase 2 (PB2) proteins are thought to play essential roles in these processes by enabling avian influenza viruses to infect mammals and replicate efficiently in their new host. Here, we summarize our current knowledge of the contributions of HA, PB2, and other viral components to virus transmission and the formation of new virus lineages. PMID:25812763

  17. Household Transmission of Influenza Virus.

    PubMed

    Tsang, Tim K; Lau, Lincoln L H; Cauchemez, Simon; Cowling, Benjamin J

    2016-02-01

    Human influenza viruses cause regular epidemics and occasional pandemics with a substantial public health burden. Household transmission studies have provided valuable information on the dynamics of influenza transmission. We reviewed published studies and found that once one household member is infected with influenza, the risk of infection in a household contact can be up to 38%, and the delay between onset in index and secondary cases is around 3 days. Younger age was associated with higher susceptibility. In the future, household transmission studies will provide information on transmission dynamics, including the correlation of virus shedding and symptoms with transmission, and the correlation of new measures of immunity with protection against infection. PMID:26612500

  18. Analysis of antigenic variation in equine 2 influenza A viruses.

    PubMed

    Hinshaw, V S; Naeve, C W; Webster, R G; Douglas, A; Skehel, J J; Bryans, J

    1983-01-01

    Influenza outbreaks involving viruses of the H3N8 subtype (equine 2) often occur in vaccinated horses. For this reason, a series of influenza viruses of the H3N8 subtype were examined to determine if antigenic variation could be detected in isolates during the period 1963-81. Antigenic analyses with post-infection ferret sera and monoclonal antibodies showed that the haemagglutinins of recent isolates were antigenically distinguishable from the prototype A/eq/Miami/1/63 and that antigenically distinguishable groups of equine 2 viruses co-circulate in the horse population. Based on these studies, it is recommended that a recent equine strain, A/equine/Fontainebleu/1/79 or A/equine/Kentucky/1/81, serve as an additional prototype strain for this subtype.Antigenic variation in equine 2 viruses may be of epidemiological significance, yet the overall conservation of these strains makes it unlikely that vaccine failures can be attributed solely to antigenic changes in these viruses. A sufficiently potent vaccine, containing a current representative of the most prevalent equine 2 strain, may improve the protection afforded by equine vaccines. PMID:6601538

  19. Global circulation patterns of seasonal influenza viruses vary with antigenic drift

    NASA Astrophysics Data System (ADS)

    Bedford, Trevor; Riley, Steven; Barr, Ian G.; Broor, Shobha; Chadha, Mandeep; Cox, Nancy J.; Daniels, Rodney S.; Gunasekaran, C. Palani; Hurt, Aeron C.; Kelso, Anne; Klimov, Alexander; Lewis, Nicola S.; Li, Xiyan; McCauley, John W.; Odagiri, Takato; Potdar, Varsha; Rambaut, Andrew; Shu, Yuelong; Skepner, Eugene; Smith, Derek J.; Suchard, Marc A.; Tashiro, Masato; Wang, Dayan; Xu, Xiyan; Lemey, Philippe; Russell, Colin A.

    2015-07-01

    Understanding the spatiotemporal patterns of emergence and circulation of new human seasonal influenza virus variants is a key scientific and public health challenge. The global circulation patterns of influenza A/H3N2 viruses are well characterized, but the patterns of A/H1N1 and B viruses have remained largely unexplored. Here we show that the global circulation patterns of A/H1N1 (up to 2009), B/Victoria, and B/Yamagata viruses differ substantially from those of A/H3N2 viruses, on the basis of analyses of 9,604 haemagglutinin sequences of human seasonal influenza viruses from 2000 to 2012. Whereas genetic variants of A/H3N2 viruses did not persist locally between epidemics and were reseeded from East and Southeast Asia, genetic variants of A/H1N1 and B viruses persisted across several seasons and exhibited complex global dynamics with East and Southeast Asia playing a limited role in disseminating new variants. The less frequent global movement of influenza A/H1N1 and B viruses coincided with slower rates of antigenic evolution, lower ages of infection, and smaller, less frequent epidemics compared to A/H3N2 viruses. Detailed epidemic models support differences in age of infection, combined with the less frequent travel of children, as probable drivers of the differences in the patterns of global circulation, suggesting a complex interaction between virus evolution, epidemiology, and human behaviour.

  20. 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. PMID:25231137

  1. Avian Influenza A Virus Infections in Humans

    MedlinePlus

    ... Research Making a Candidate Vaccine Virus Related Links Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... Submit What's this? Submit Button Past Newsletters Avian Influenza A Virus Infections in Humans Language: English Españ ...

  2. The soft palate is an important site of adaptation for transmissible influenza viruses.

    PubMed

    Lakdawala, Seema S; Jayaraman, Akila; Halpin, Rebecca A; Lamirande, Elaine W; Shih, Angela R; Stockwell, Timothy B; Lin, Xudong; Simenauer, Ari; Hanson, Christopher T; Vogel, Leatrice; Paskel, Myeisha; Minai, Mahnaz; Moore, Ian; Orandle, Marlene; Das, Suman R; Wentworth, David E; Sasisekharan, Ram; Subbarao, Kanta

    2015-10-01

    Influenza A viruses pose a major public health threat by causing seasonal epidemics and sporadic pandemics. Their epidemiological success relies on airborne transmission from person to person; however, the viral properties governing airborne transmission of influenza A viruses are complex. Influenza A virus infection is mediated via binding of the viral haemagglutinin (HA) to terminally attached α2,3 or α2,6 sialic acids on cell surface glycoproteins. Human influenza A viruses preferentially bind α2,6-linked sialic acids whereas avian influenza A viruses bind α2,3-linked sialic acids on complex glycans on airway epithelial cells. Historically, influenza A viruses with preferential association with α2,3-linked sialic acids have not been transmitted efficiently by the airborne route in ferrets. Here we observe efficient airborne transmission of a 2009 pandemic H1N1 (H1N1pdm) virus (A/California/07/2009) engineered to preferentially bind α2,3-linked sialic acids. Airborne transmission was associated with rapid selection of virus with a change at a single HA site that conferred binding to long-chain α2,6-linked sialic acids, without loss of α2,3-linked sialic acid binding. The transmissible virus emerged in experimentally infected ferrets within 24 hours after infection and was remarkably enriched in the soft palate, where long-chain α2,6-linked sialic acids predominate on the nasopharyngeal surface. Notably, presence of long-chain α2,6-linked sialic acids is conserved in ferret, pig and human soft palate. Using a loss-of-function approach with this one virus, we demonstrate that the ferret soft palate, a tissue not normally sampled in animal models of influenza, rapidly selects for transmissible influenza A viruses with human receptor (α2,6-linked sialic acids) preference. PMID:26416728

  3. Swine Influenza Virus: Emerging Understandings

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Avian influenza virus in pregnancy.

    PubMed

    Liu, Shelan; Sha, Jianping; Yu, Zhao; Hu, Yan; Chan, Ta-Chien; Wang, Xiaoxiao; Pan, Hao; Cheng, Wei; Mao, Shenghua; Zhang, Run Ju; Chen, Enfu

    2016-07-01

    The unprecedented epizootic of avian influenza viruses, such as H5N1, H5N6, H7N1 and H10N8, has continued to cause disease in humans in recent years. In 2013, another novel influenza A (H7N9) virus emerged in China, and 30% of those patients died. Pregnant women are particularly susceptible to avian influenza and are more likely to develop severe complications and to die, especially when infection occurs in the middle and late trimesters. Viremia is believed to occur infrequently, and thus vertical transmission induced by avian influenza appears to be rare. However, avian influenza increases the risk of adverse pregnancy outcomes, including spontaneous abortion, preterm birth and fatal distress. This review summarises 39 cases of pregnant women and their fetuses from different countries dating back to 1997, including 11, 15 and 13 infections with H7N9, H5N1 and the 2009 pandemic influenza (H1N1), respectively. We analysed the epidemic features, following the geographical, population and pregnancy trimester distributions; underlying diseases; exposure history; medical timelines; human-to-human transmission; pathogenicity and vertical transmission; antivirus treatments; maternal severity and mortality and pregnancy outcome. The common experiences reported in different countries and areas suggest that early identification and treatment are imperative. In the future, vigilant virologic and epidemiologic surveillance systems should be developed to monitor avian influenza viruses during pregnancy. Furthermore, extensive study on the immune mechanisms should be conducted, as this will guide safe, rational immunomodulatory treatment among this high-risk population. Most importantly, we should develop a universal avian influenza virus vaccine to prevent outbreaks of the different subtypes. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27187752

  5. Novel hemagglutinin-based influenza virus inhibitors

    PubMed Central

    Shen, Xintian; Zhang, Xuanxuan

    2013-01-01

    Influenza virus has caused seasonal epidemics and worldwide pandemics, which caused tremendous loss of human lives and socioeconomics. Nowadays, only two classes of anti-influenza drugs, M2 ion channel inhibitors and neuraminidase inhibitors respectively, are used for prophylaxis and treatment of influenza virus infection. Unfortunately, influenza virus strains resistant to one or all of those drugs emerge frequently. Hemagglutinin (HA), the glycoprotein in influenza virus envelope, plays a critical role in viral binding, fusion and entry processes. Therefore, HA is a promising target for developing anti-influenza drugs, which block the initial entry step of viral life cycle. Here we reviewed recent understanding of conformational changes of HA in protein folding and fusion processes, and the discovery of HA-based influenza entry inhibitors, which may provide more choices for preventing and controlling potential pandemics caused by multi-resistant influenza viruses. PMID:23977436

  6. Evaluation of a vectored equine herpesvirus type 1 (EHV-1) vaccine expressing H3 haemagglutinin in the protection of dogs against canine influenza

    PubMed Central

    Rosas, Cristina; Van de Walle, Gerlinde R.; Metzger, Stephan M.; Hoelzer, Karin; Dubovi, Edward J.; Kim, Sung G.; Parrish, Colin R.; Osterrieder, Nikolaus

    2008-01-01

    In 2004, canine influenza virus (CIV) was identified as a respiratory pathogen of dogs for the first time and is closely related to H3N8 equine influenza virus (EIV). We generated a recombinant vectored vaccine that expresses H3 of a recent isolate of EIV using equine herpesvirus type 1 (EHV-1) as the delivery vehicle. This EHV-1 vectored vaccine exhibited robust and stable EIV H3 expression and induced a strong influenza virus-specific response in both mice and dogs upon intranasal or subcutaneous administration. Furthermore, upon challenge with the recent CIV isolate A/canine/PA/10915-07, protection of vaccinated dogs could be demonstrated by a significant reduction in clinical sings, and, more importantly, by a significant reduction in virus shedding. We concluded that the EHV-1/H3 recombinant vector can be a valuable alternative for protection of dogs against clinical disease induced by CIV and can significantly reduce spread. PMID:18407383

  7. 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

  8. Selecting Viruses for the Seasonal Influenza Vaccine

    MedlinePlus

    ... which viruses are selected for use in vaccine production? The influenza viruses in the seasonal flu vaccine ... to get a good vaccine virus for vaccine production? There are a number of factors that can ...

  9. Detection of influenza C virus but not influenza D virus in Scottish respiratory samples

    PubMed Central

    Smith, Donald B.; Gaunt, Eleanor R.; Digard, Paul; Templeton, Kate; Simmonds, Peter

    2016-01-01

    Background A newly proposed genus of influenza virus (influenza D) is associated with respiratory disease in pigs and cattle. The novel virus is most closely related to human influenza C virus and can infect ferrets but infection has not been reported in humans. Objectives To ascertain if influenza D virus can be detected retrospectively in patient respiratory samples. Study design 3300 human respiratory samples from Edinburgh, Scotland, covering the period 2006–2008, were screened in pools of 10 by RT-PCR using primers capable of detecting both influenza C and D viruses. Results Influenza D was not detected in any sample. Influenza C was present in 6 samples (0.2%), compared with frequencies of 3.3% and 0.9% for influenza A and B viruses from RT-PCR testing of respiratory samples over the same period. Influenza C virus was detected in samples from individuals <2 years or >45 years old, with cases occurring throughout the year. Phylogenetic analysis of nearly complete sequences of all seven segments revealed the presence of multiple, reassortant lineages. Conclusion We were unable to detect viruses related to influenza D virus in human respiratory samples. Influenza C virus was less prevalent than influenza A and B viruses, was associated with mild disease in the young (<2 years) and old (>45 years) and comprised multiple, reassortant lineages. Inclusion of influenza C virus as part of a diagnostic testing panel for respiratory infections would be of limited additional value. PMID:26655269

  10. 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. PMID:25965069

  11. Serological Evidence of Influenza A Viruses in Frugivorous Bats from Africa

    PubMed Central

    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 5μl 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. PMID:25965069

  12. 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

  13. Immunosuppression During Influenza Virus Infection

    PubMed Central

    Kantzler, G. B.; Lauteria, S. F.; Cusumano, C. L.; Lee, J. D.; Ganguly, R.; Waldman, R. H.

    1974-01-01

    The effects of a live attenuated influenza vaccine and subsequent challenge with virulent influenza virus on the delayed hypersensitivity skin test, and the in vitro response of lymphocytes were evaluated. Volunteers were skin tested before and after administration of vaccine or placebo and challenge with PPD (a purified protein derivative of Mycobacterium tuberculosis), candida, mumps, and trichophytin, and their lymphocytes were tested for [3H]thymidine uptake in response to phytohemagglutin. Of eight volunteers who showed evidence of viral replication after administration of the attenuated vaccine, four had a significant diminution in their skin test response, whereas 8 of 13 volunteers infected with virulent influenza virus showed a diminution. Of the 21 volunteers who were infected with either attenuated or virulent influenza virus, 12 showed suppression of their phytohemagglutin response. None of the volunteers who were given placebo vaccine, or who showed no evidence for viral replication after immunization or challenge, had a suppression of their skin test or phytohemagglutin responses. Although most of the infected volunteers demonstrated suppression of their T-cell function, there was no evidence of a similar suppression of B-cell function. PMID:16558116

  14. Cross-neutralization between three mumps viruses & mapping of haemagglutinin-neuraminidase (HN) epitopes

    PubMed Central

    Vaidya, Sunil R.; Dvivedi, Garima M.; Jadhav, Santoshkumar M.

    2016-01-01

    Background & objectives: The reports from the countries where mumps vaccine is given as routine immunization suggest differences in mumps virus neutralizing antibody titres when tested with vaccine and wild type viruses. Such reports are unavailable from countries like India where mumps vaccine is not included in routine immunization. We, therefore, undertook this study to understand the cross-neutralization activity of Indian mumps viruses. Methods: By using commercial mumps IgG enzyme immunoassay (EIA) and a rapid focus reduction neutralization test (FRNT), a panel of serum samples was tested. The panel consisted of 14 acute and 14 convalescent serum samples collected during a mumps outbreak and 18 archived serum samples. Two wild types (genotypes C and G) and Leningrad-Zagreb vaccine strain (genotype N) were used for the challenge experiments and FRNT titres were determined and further compared. The HN protein sequence of three mumps viruses was analyzed for the presence of key epitopes. Results: All serum samples effectively neutralized mumps virus wild types and a vaccine strain. However, significantly lower FRNT titres were noted to wild types than to vaccine strain (P<0.05). The comparison between EIA and FRNT results revealed 95.6 per cent agreement. No amino acid changes were seen in the epitopes in the Indian wild type strains. All potential N-linked glycosylation sites were observed in Indian strains. Interpretation & conclusions: Good cross-neutralization activity was observed for three mumps virus strains, however, higher level of FRNT titres was detected for mumps virus vaccine strain compared to Indian wild type isolates. PMID:26997012

  15. The evolutionary dynamics of influenza A virus adaptation to mammalian hosts

    PubMed Central

    Bhatt, S.; Lam, T. T.; Lycett, S. J.; Leigh Brown, A. J.; Bowden, T. A.; Holmes, E. C.; Guan, Y.; Wood, J. L. N.; Brown, I. H.; Kellam, P.; Pybus, O. G.; Brown, Ian; Brookes, Sharon; Germundsson, Anna; Cook, Alex; Williamson, Susanna; Essen, Stephen; Garcon, Fanny; Gunn, George; Sanchez, Manuel; Marques, Diogo; Wood, James; Tucker, Dan; McCrone, Ian; Gog, Julia; Saenz, Roberto; Staff, Meg; Murcia, Pablo; Barclay, Wendy; Donnelly, Christl; Elderfield, Ruth A.; Kellam, Paul; Baillie, Greg; Coulter, Eve; Wieland, Barbara; Mastin, Alex; McCauley, John; Brown, Andy Leigh; Lycett, Sam; Woolhouse, Mark; Pybus, Oliver; Bhatt, Samir; Hayward, Andrew; Ishola, David; Archibald, Alan; Freeman, Tom; Charleston, Bryan; LeFevre, Eric; Bailey, Mick; Inman, Charlotte; Stokes, Chris; Chang, Kin Chow; Dunham, Stephen; White, Gavin; Nguyen-Van-Tam, Jonathan; Enstone, Joanne

    2013-01-01

    Few questions on infectious disease are more important than understanding how and why avian influenza A viruses successfully emerge in mammalian populations, yet little is known about the rate and nature of the virus’ genetic adaptation in new hosts. Here, we measure, for the first time, the genomic rate of adaptive evolution of swine influenza viruses (SwIV) that originated in birds. By using a curated dataset of more than 24 000 human and swine influenza gene sequences, including 41 newly characterized genomes, we reconstructed the adaptive dynamics of three major SwIV lineages (Eurasian, EA; classical swine, CS; triple reassortant, TR). We found that, following the transfer of the EA lineage from birds to swine in the late 1970s, EA virus genes have undergone substantially faster adaptive evolution than those of the CS lineage, which had circulated among swine for decades. Further, the adaptation rates of the EA lineage antigenic haemagglutinin and neuraminidase genes were unexpectedly high and similar to those observed in human influenza A. We show that the successful establishment of avian influenza viruses in swine is associated with raised adaptive evolution across the entire genome for many years after zoonosis, reflecting the contribution of multiple mutations to the coordinated optimization of viral fitness in a new environment. This dynamics is replicated independently in the polymerase genes of the TR lineage, which established in swine following separate transmission from non-swine hosts. PMID:23382435

  16. Influenza virus neuraminidase: structure, antibodies, and inhibitors.

    PubMed Central

    Colman, P. M.

    1994-01-01

    The determination of the 3-dimensional structure of the influenza virus neuraminidase in 1983 has served as a platform for understanding interactions between antibodies and protein antigens, for investigating antigenic variation in influenza viruses, and for devising new inhibitors of the enzyme. That work is reviewed here, together with more recent developments that have resulted in one of the inhibitors entering clinical trials as an anti-influenza virus drug. PMID:7849585

  17. Newcastle disease virus fusion and haemagglutinin-neuraminidase proteins contribute to its macrophage host range

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease virus (NDV) is an avian paramyxovirus that causes significant economic damage to international poultry industry. Different strains of NDV express a wide range of virulence that is primarily dependent on the amino acid sequence of the strain’s fusion (F) protein cleavage site. Two c...

  18. DIVA vaccination strategies for avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccination for both low pathogenic and highly pathogenic avian influenza is commonly used for countries that have been endemic for avian influenza influenza virus, but stamping out policies are common for countries that are normally free of the disease. Stamping out policies of euthanizing infecte...

  19. Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA

    PubMed Central

    Verity, Erin E.; Camuglia, Sarina; Agius, Catherine T.; Ong, Chi; Shaw, Robert; Barr, Ian; Middleton, Deborah; Rockman, Steven

    2011-01-01

    Please cite this paper as: Verity et al. (2011) Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA. Influenza and Other Respiratory Viruses DOI:10.1111/j.1750‐2659.2011.00273.x. Background  Vaccination is considered the most effective means of reducing influenza burden. The emergence of H5N1 and pandemic spread of novel H1N1/2009 viruses reinforces the need to have strategies in place to rapidly develop seed viruses for vaccine manufacture. Methods  Candidate pandemic vaccine strains consisting of the circulating strain haemagglutinin (HA) and neuraminidase (NA) in an A/PR/8/34 backbone were generated using alternative synthetic DNA approaches, including site‐directed mutagenesis of DNA encoding related virus strains, and rapid generation of virus using synthetic DNA cloned into plasmid vectors. Results  Firstly, synthetic A/Bar Headed Goose/Qinghai/1A/2005 (H5N1) virus was generated from an A/Vietnam/1194/2004 template using site‐directed mutagenesis. Secondly, A/Whooper Swan/Mongolia/244/2005 (H5N1) and A/California/04/09 (H1N1) viruses were generated using synthetic DNA encoding the viral HA and NA genes. Replication and antigenicity of the synthetic viruses were comparable to that of the corresponding non‐synthetic viruses. Conclusions  In the event of an influenza pandemic, the use of these approaches may significantly reduce the time required to generate and distribute the vaccine seed virus and vaccine manufacture. These approaches also offer the advantage of not needing to handle wild‐type virus, potentially diminishing biocontainment requirements. PMID:21771285

  20. Influenza virus activation of the interferon system

    PubMed Central

    Killip, Marian J.; Fodor, Ervin; Randall, Richard E.

    2015-01-01

    The host interferon (IFN) response represents one of the first barriers that influenza viruses must surmount in order to establish an infection. Many advances have been made in recent years in understanding the interactions between influenza viruses and the interferon system. In this review, we summarise recent work regarding activation of the type I IFN response by influenza viruses, including attempts to identify the viral RNA responsible for IFN induction, the stage of the virus life cycle at which it is generated and the role of defective viruses in this process. PMID:25678267

  1. Virulence determinants of pandemic influenza viruses

    PubMed Central

    Tscherne, Donna M.; García-Sastre, Adolfo

    2011-01-01

    Influenza A viruses cause recurrent, seasonal epidemics and occasional global pandemics with devastating levels of morbidity and mortality. The ability of influenza A viruses to adapt to various hosts and undergo reassortment events ensures constant generation of new strains with unpredictable degrees of pathogenicity, transmissibility, and pandemic potential. Currently, the combination of factors that drives the emergence of pandemic influenza is unclear, making it impossible to foresee the details of a future outbreak. Identification and characterization of influenza A virus virulence determinants may provide insight into genotypic signatures of pathogenicity as well as a more thorough understanding of the factors that give rise to pandemics. PMID:21206092

  2. Evaluation of a vectored equine herpesvirus type 1 (EHV-1) vaccine expressing H3 haemagglutinin in the protection of dogs against canine influenza.

    PubMed

    Rosas, Cristina; Van de Walle, Gerlinde R; Metzger, Stephan M; Hoelzer, Karin; Dubovi, Edward J; Kim, Sung G; Parrish, Colin R; Osterrieder, Nikolaus

    2008-05-01

    In 2004, canine influenza virus (CIV) was identified as a respiratory pathogen of dogs for the first time and found to be closely related to H3N8 equine influenza virus (EIV). We generated a recombinant vectored vaccine that expresses H3 of a recent isolate of EIV using equine herpesvirus type 1 (EHV-1) as the delivery vehicle. This EHV-1 vectored vaccine exhibited robust and stable EIV H3 expression and induced a strong influenza virus-specific response in both mice and dogs upon intranasal or subcutaneous administration. Furthermore, upon challenge with the recent CIV isolate A/canine/PA/10915-07, protection of vaccinated dogs could be demonstrated by a significant reduction in clinical sings, and, more importantly, by a significant reduction in virus shedding. We concluded that the EHV-1/H3 recombinant vector can be a valuable alternative for protection of dogs against clinical disease induced by CIV and can significantly reduce virus spread. PMID:18407383

  3. Swine influenza virus: epidemiology and vaccine concerns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. Swine influenza virus (SIV) is a primary cause of respiratory disease in swine and a component of the porcine respiratory disease complex (PRDC). Influenza viruses are an important health and economic concern for swine producers throughout the world. Swine operations may be affected by...

  4. A brief introduction to avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) is caused by a type A influenza virus isolated from and adapted to an avian host. This chapter covers the basic physicochemical aspects of AIV including; virus family and properties, subtype classification; basic molecular biology and genetics. The avian host range and ecology...

  5. The receptor preference of influenza viruses

    PubMed Central

    Meng, Bo; Marriott, Anthony C.; Dimmock, Nigel J.

    2010-01-01

    Please cite this paper as: Meng et al. (2010) The receptor preference of influenza viruses. Influenza and Other Respiratory Viruses 4(3), 147–153. Objectives  The cell surface receptor used by an influenza virus to infect that cell is an N‐acetyl neuraminic acid (NANA) residue terminally linked by an alpha2,3 or alpha2,6 bond to a carbohydrate moiety of a glycoprotein or glycolipid. Our aim was to determine a quick and technically simple method to determine cell receptor usage by whole influenza A virus particles. Methods  We employed surface plasmon resonance to detect the binding of viruses to fetuin, a naturally occurring glycoprotein that has both alpha2,3‐ and alpha2,6‐linked NANA, and free 3′‐sialyllactose or 6′‐sialyllactose to compete virus binding. All virus stocks were produced in embryonated chicken’s eggs. Results  The influenza viruses tested bound preferentially to NANAalpha2,3Gal or to NANAalpha2,6Gal, or showed no preference. Two PR8 viruses had different binding preferences. Binding preferences of viruses correlated well with their known biological properties. Conclusions  Our data suggest that it is not easy to predict receptor usage by influenza viruses. However, direct experimental determination as described here can inform experiments concerned with viral pathogenesis, biology and structure. In principle, the methodology can be used for any virus that binds to a terminal NANA residue. PMID:20409211

  6. Two novel reassortants of avian influenza A (H5N6) virus in China.

    PubMed

    Bi, Yuhai; Mei, Kun; Shi, Weifeng; Liu, Di; Yu, Xiaolan; Gao, Zhimin; Zhao, Lihua; Gao, George F; Chen, Jianjun; Chen, Quanjiao

    2015-05-01

    Eight avian influenza A (H5N6) viruses were isolated from live poultry markets (LPMs) in Sichuan and Jiangxi Provinces in China in 2014, including those close to the county where the human H5N6 infection occurred. Genetic and phylogenetic analyses revealed that these H5N6 viruses were novel reassortants between H5N1 clade 2.3.4 and H6N6 viruses, and had evolved into two distinct lineages (Sichuan and Jiangxi). Moreover, the human H5N6 virus was closely related to the avian-source viruses of Sichuan lineage. Notably, H5N6 viruses contained a T160A substitution in the haemagglutinin protein and an 11 aa deletion in the neuraminidase stalk, which may aid in enhancing viral affinity for human-like receptors and virulence in mammals. As the H5N1 virus infects humans through direct contact, infection with the novel H5N6 virus raised significant concerns that the H5 subtype was a likely candidate for a pandemic. Therefore, extensive and long-term surveillance of avian influenza viruses in LPMs is essential. PMID:25604926

  7. Live, attenuated influenza virus (LAIV) vehicles are strong inducers of immunity toward influenza B virus

    PubMed Central

    Huber, Victor C.; Kleimeyer, Loren H.; McCullers, Jonathan A.

    2008-01-01

    Historically, vaccines developed toward influenza viruses of the B type using methodologies developed for influenza A viruses as a blueprint have not been equally efficacious or effective. Because most influenza research and public attention concerns influenza A viruses, these shortcomings have not been adequately addressed. In this manuscript, we utilized different influenza vaccine vehicles to compare immunogenicity and protection in mice and ferrets after vaccination against an influenza B virus. We report that plasmid DNA vaccines demonstrate low immunogenicity profiles and poor protection compared to either whole, inactivated influenza virus (IIV) or, live, attenuated influenza virus (LAIV) vaccines. When mixed prime:boost regimens using LAIV and IIV were studied, we observed a boosting effect in mice after priming with LAIV that was not seen when IIV was used as the prime. In ferrets LAIV induced high antibody titers after a single dose and provided a boost in IIV-primed animals. Regimens including LAIV as a prime demonstrated enhanced protection, and adjuvantation was required for efficacy using the IIV preparation. Our results differ from generally accepted influenza A virus vaccine models, and argue that strategies for control of influenza B virus should be considered separately from those for influenza A virus. PMID:18708106

  8. Using epidemics to map H3 equine influenza virus determinants of antigenicity.

    PubMed

    Woodward, Alana; Rash, Adam S; Medcalf, Elizabeth; Bryant, Neil A; Elton, Debra M

    2015-07-01

    Equine influenza is a major cause of respiratory infections in horses and causes widespread epidemics, despite the availability of commercial vaccines. Antigenic drift within the haemagglutinin (HA) glycoprotein is thought to play a part in vaccination breakdown. Here, we carried out a detailed investigation of the 1989 UK outbreak, using reverse genetics and site-directed mutagenesis, to determine the individual contribution of amino acid substitutions within HA. Mutations at positions 159, 189 and 227 all altered antigenicity, as measured by haemagglutination-inhibition assays. We also compared HA sequences for epidemic and vaccine strains from four epidemics and found that at least 8 amino acid differences were present, affecting multiple antigenic sites. Substitutions within antigenic site B and at least one other were associated with each outbreak, we also identified changes in loop regions close to antigenic sites that have not previously been highlighted for human H3 influenza viruses. PMID:25797606

  9. The evolution of human influenza viruses.

    PubMed Central

    Hay, A J; Gregory, V; Douglas, A R; Lin, Y P

    2001-01-01

    The evolution of influenza viruses results in (i) recurrent annual epidemics of disease that are caused by progressive antigenic drift of influenza A and B viruses due to the mutability of the RNA genome and (ii) infrequent but severe pandemics caused by the emergence of novel influenza A subtypes to which the population has little immunity. The latter characteristic is a consequence of the wide antigenic diversity and peculiar host range of influenza A viruses and the ability of their segmented RNA genomes to undergo frequent genetic reassortment (recombination) during mixed infections. Contrasting features of the evolution of recently circulating influenza AH1N1, AH3N2 and B viruses include the rapid drift of AH3N2 viruses as a single lineage, the slow replacement of successive antigenic variants of AH1N1 viruses and the co-circulation over some 25 years of antigenically and genetically distinct lineages of influenza B viruses. Constant monitoring of changes in the circulating viruses is important for maintaining the efficacy of influenza vaccines in combating disease. PMID:11779385

  10. Antigenic and genomic characterization of human influenza A and B viruses circulating in Argentina after the introduction of influenza A(H1N1)pdm09.

    PubMed

    Russo, Mara L; Pontoriero, Andrea V; Benedetti, Estefania; Czech, Andrea; Avaro, Martin; Periolo, Natalia; Campos, Ana M; Savy, Vilma L; Baumeister, Elsa G

    2014-12-01

    This study was conducted as part of the Argentinean Influenza and other Respiratory Viruses Surveillance Network, in the context of the Global Influenza Surveillance carried out by the World Health Organization (WHO). The objective was to study the activity and the antigenic and genomic characteristics of circulating viruses for three consecutive seasons (2010, 2011 and 2012) in order to investigate the emergence of influenza viral variants. During the study period, influenza virus circulation was detected from January to December. Influenza A and B, and all current subtypes of human influenza viruses, were present each year. Throughout the 2010 post-pandemic season, influenza A(H1N1)pdm09, unexpectedly, almost disappeared. The haemagglutinin (HA) of the A(H1N1)pdm09 viruses studied were segregated in a different genetic group to those identified during the 2009 pandemic, although they were still antigenically closely related to the vaccine strain A/California/07/2009. Influenza A(H3N2) viruses were the predominant strains circulating during the 2011 season, accounting for nearly 76 % of influenza viruses identified. That year, all HA sequences of the A(H3N2) viruses tested fell into the A/Victoria/208/2009 genetic clade, but remained antigenically related to A/Perth/16/2009 (reference vaccine recommended for this three-year period). A(H3N2) viruses isolated in 2012 were antigenically closely related to A/Victoria/361/2011, recommended by the WHO as the H3 component for the 2013 Southern Hemisphere formulation. B viruses belonging to the B/Victoria lineage circulated in 2010. A mixed circulation of viral variants of both B/Victoria and B/Yamagata lineages was detected in 2012, with the former being predominant. A(H1N1)pdm09 viruses remained antigenically closely related to the vaccine virus A/California/7/2009; A(H3N2) viruses continually evolved into new antigenic clusters and both B lineages, B/Victoria/2/87-like and B/Yamagata/16/88-like viruses, were observed

  11. Neutralization enzyme immunoassay for influenza virus.

    PubMed Central

    Benne, C A; Harmsen, M; De Jong, J C; Kraaijeveld, C A

    1994-01-01

    A neutralization enzyme immunoassay (N-EIA) was developed for the detection of antibody titer rises in sera of patients infected with influenza A (H3N2) virus. In this N-EIA, a selected strain of influenza A (H3N2) virus was added to monolayers of LLC-MK2 cells in microtiter plates. After 24 h, the replicated virus could be demonstrated with a virus-specific enzyme-labeled monoclonal antibody. Preincubation of the influenza virus with convalescent-phase sera of patients infected with influenza A (H3N2) virus resulted 1 day later in decreased absorbance values that could be used for calculation of neutralization titers. From use of paired serum samples from 10 patients with a history of flu-like symptoms, the results obtained with N-EIA correlated well (r = 0.83) with those of the standard hemagglutination inhibition test. PMID:8027355

  12. Inhibition of endosomal fusion activity of influenza virus by Rheum tanguticum (da-huang).

    PubMed

    Lin, Ta-Jen; Lin, Chwan-Fwu; Chiu, Cheng-Hsun; Lee, Ming-Chung; Horng, Jim-Tong

    2016-01-01

    Rhubarb (Rheum tanguticum; da-huang in Chinese medicine) is a herbal medicine that has been used widely for managing fever and removing toxicity. In this study, we investigated how rhubarb inhibits influenza virus during the early stage of the infectious cycle using different functional assays. A non-toxic ethanolic extract of rhubarb (Rex) inhibited several H1N1 subtypes of influenza A viruses in Madin-Darby canine kidney cells, including strains that are clinically resistant to oseltamivir. Time course analysis of Rex addition showed that viral entry was one of the steps that was inhibited by Rex. We also confirmed that Rex effectively inhibited viral attachment and penetration into the host cells. The inhibition of red blood cell haemolysis and cell-cell fusion by Rex suggests that Rex may block haemagglutinin-mediated fusion (virus-endosome fusion) during the fusion/uncoating step. Rex has the capacity to inhibit influenza viruses by blocking viral endocytosis. Thus, rhubarb might provide an alternative therapeutic approach when resistant viruses become more prevalent. PMID:27302738

  13. Meeting report: 4th ISIRV antiviral group conference: Novel antiviral therapies for influenza and other respiratory viruses.

    PubMed

    McKimm-Breschkin, Jennifer L; Fry, Alicia M

    2016-05-01

    The International Society for Influenza and other Respiratory Virus Diseases (isirv) held its 4th Antiviral Group Conference at the University of Texas on 2-4 June, 2015. With emerging resistance to the drugs currently licensed for treatment and prophylaxis of influenza viruses, primarily the neuraminidase inhibitor oseltamivir phosphate (Tamiflu) and the M2 inhibitors amantadine and rimantadine, and the lack of effective interventions against other respiratory viruses, the 3-day programme focused on the discovery and development of inhibitors of several virus targets and key host cell factors involved in virus replication or mediating the inflammatory response. Virus targets included the influenza haemagglutinin, neuraminidase and M2 proteins, and both the respiratory syncytial virus and influenza polymerases and nucleoproteins. Therapies for rhinoviruses and MERS and SARS coronaviruses were also discussed. With the emerging development of monoclonal antibodies as therapeutics, the potential implications of antibody-dependent enhancement of disease were also addressed. Topics covered all aspects from structural and molecular biology to preclinical and clinical studies. The importance of suitable clinical trial endpoints and regulatory issues were also discussed from the perspectives of both industry and government. This meeting summary provides an overview, not only for the conference participants, but also for those interested in the current status of antivirals for respiratory viruses. PMID:26872862

  14. Integrating historical, clinical and molecular genetic data in order to explain the origin and virulence of the 1918 Spanish influenza virus.

    PubMed Central

    Taubenberger, J K; Reid, A H; Janczewski, T A; Fanning, T G

    2001-01-01

    The Spanish influenza pandemic of 1918-1919 caused acute illness in 25-30% of the world's population and resulted in the death of 40 million people. The complete genomic sequence of the 1918 influenza virus will be deduced using fixed and frozen tissues of 1918 influenza victims. Sequence and phylogenetic analyses of the complete 1918 haemagglutinin (HA) and neuraminidase (NA) genes show them to be the most avian-like of mammalian sequences and support the hypothesis that the pandemic virus contained surface protein-encoding genes derived from an avian influenza strain and that the 1918 virus is very similar to the common ancestor of human and classical swine H1N1 influenza strains. Neither the 1918 HA genes nor the NA genes possessed mutations that are known to increase tissue tropicity, which accounts for the virulence of other influenza strains such as A/WSN/33 or fowl plague viruses. The complete sequence of the nonstructural (NS) gene segment of the 1918 virus was deduced and tested for the hypothesis that the enhanced virulence in 1918 could have been due to type I interferon inhibition by the NS1 protein. The results from these experiments were inconclusive. Sequence analysis of the 1918 pandemic influenza virus is allowing us to test hypotheses as to the origin and virulence of this strain. This information should help to elucidate how pandemic influenza strains emerge and what genetic features contribute to their virulence. PMID:11779381

  15. Riems influenza a typing array (RITA): An RT-qPCR-based low density array for subtyping avian and mammalian influenza a viruses.

    PubMed

    Hoffmann, Bernd; Hoffmann, Donata; Henritzi, Dinah; Beer, Martin; Harder, Timm C

    2016-01-01

    Rapid and sensitive diagnostic approaches are of the utmost importance for the detection of humans and animals infected by specific influenza virus subtype(s). Cascade-like diagnostics starting with the use of pan-influenza assays and subsequent subtyping devices are normally used. Here, we demonstrated a novel low density array combining 32 TaqMan(®) real-time RT-PCR systems in parallel for the specific detection of the haemagglutinin (HA) and neuraminidase (NA) subtypes of avian and porcine hosts. The sensitivity of the newly developed system was compared with that of the pan-influenza assay, and the specificity of all RT-qPCRs was examined using a broad panel of 404 different influenza A virus isolates representing 45 different subtypes. Furthermore, we analysed the performance of the RT-qPCR assays with diagnostic samples obtained from wild birds and swine. Due to the open format of the array, adaptations to detect newly emerging influenza A virus strains can easily be integrated. The RITA array represents a competitive, fast and sensitive subtyping tool that requires neither new machinery nor additional training of staff in a lab where RT-qPCR is already established. PMID:27256976

  16. Riems influenza a typing array (RITA): An RT-qPCR-based low density array for subtyping avian and mammalian influenza a viruses

    PubMed Central

    Hoffmann, Bernd; Hoffmann, Donata; Henritzi, Dinah; Beer, Martin; Harder, Timm C.

    2016-01-01

    Rapid and sensitive diagnostic approaches are of the utmost importance for the detection of humans and animals infected by specific influenza virus subtype(s). Cascade-like diagnostics starting with the use of pan-influenza assays and subsequent subtyping devices are normally used. Here, we demonstrated a novel low density array combining 32 TaqMan® real-time RT-PCR systems in parallel for the specific detection of the haemagglutinin (HA) and neuraminidase (NA) subtypes of avian and porcine hosts. The sensitivity of the newly developed system was compared with that of the pan-influenza assay, and the specificity of all RT-qPCRs was examined using a broad panel of 404 different influenza A virus isolates representing 45 different subtypes. Furthermore, we analysed the performance of the RT-qPCR assays with diagnostic samples obtained from wild birds and swine. Due to the open format of the array, adaptations to detect newly emerging influenza A virus strains can easily be integrated. The RITA array represents a competitive, fast and sensitive subtyping tool that requires neither new machinery nor additional training of staff in a lab where RT-qPCR is already established. PMID:27256976

  17. Inhibition of endosomal fusion activity of influenza virus by Rheum tanguticum (da-huang)

    PubMed Central

    Lin, Ta-Jen; Lin, Chwan-Fwu; Chiu, Cheng-Hsun; Lee, Ming-Chung; Horng, Jim-Tong

    2016-01-01

    Rhubarb (Rheum tanguticum; da-huang in Chinese medicine) is a herbal medicine that has been used widely for managing fever and removing toxicity. In this study, we investigated how rhubarb inhibits influenza virus during the early stage of the infectious cycle using different functional assays. A non-toxic ethanolic extract of rhubarb (Rex) inhibited several H1N1 subtypes of influenza A viruses in Madin–Darby canine kidney cells, including strains that are clinically resistant to oseltamivir. Time course analysis of Rex addition showed that viral entry was one of the steps that was inhibited by Rex. We also confirmed that Rex effectively inhibited viral attachment and penetration into the host cells. The inhibition of red blood cell haemolysis and cell–cell fusion by Rex suggests that Rex may block haemagglutinin-mediated fusion (virus–endosome fusion) during the fusion/uncoating step. Rex has the capacity to inhibit influenza viruses by blocking viral endocytosis. Thus, rhubarb might provide an alternative therapeutic approach when resistant viruses become more prevalent. PMID:27302738

  18. Biology and transmission of avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The natural host and reservoir for avian influenza is in wild birds where the viral infection is typically asymptomatic. The virus primarily replicates in the enteric tract and transmission is thought to be primarily by fecal-oral transmission. Avian influenza can infect a broad host range, but fo...

  19. A brief introduction to avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) causes a disease of high economic importance for poultry production worldwide. The earliest recorded cases of probable high pathogenicity AIV in poultry were reported in Italy in the 1870’s and avian influenza been recognized in domestic poultry through the modern era of ...

  20. Environmental role in influenza virus outbreaks.

    PubMed

    Sooryanarain, Harini; Elankumaran, Subbiah

    2015-01-01

    The environmental drivers of influenza outbreaks are largely unknown. Despite more than 50 years of research, there are conflicting lines of evidence on the role of the environment in influenza A virus (IAV) survival, stability, and transmissibility. With the increasing and looming threat of pandemic influenza, it is important to understand these factors for early intervention and long-term control strategies. The factors that dictate the severity and spread of influenza would include the virus, natural and acquired hosts, virus-host interactions, environmental persistence, virus stability and transmissibility, and anthropogenic interventions. Virus persistence in different environments is subject to minor variations in temperature, humidity, pH, salinity, air pollution, and solar radiations. Seasonality of influenza is largely dictated by temperature and humidity, with cool-dry conditions enhancing IAV survival and transmissibility in temperate climates in high latitudes, whereas humid-rainy conditions favor outbreaks in low latitudes, as seen in tropical and subtropical zones. In mid-latitudes, semiannual outbreaks result from alternating cool-dry and humid-rainy conditions. The mechanism of virus survival in the cool-dry or humid-rainy conditions is largely determined by the presence of salts and proteins in the respiratory droplets. Social determinants of heath, including health equity, vaccine acceptance, and age-related illness, may play a role in influenza occurrence and spread. PMID:25422855

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

    PubMed

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

    2015-09-01

    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

  2. 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

  3. Isolation and characterisation of equine influenza viruses (H3N8) from Europe and North America from 2008 to 2009.

    PubMed

    Bryant, Neil A; Rash, Adam S; Woodward, Alana L; Medcalf, Elizabeth; Helwegen, Maud; Wohlfender, Franziska; Cruz, Fatima; Herrmann, Claudia; Borchers, Kerstin; Tiwari, Ashish; Chambers, Thomas M; Newton, J Richard; Mumford, Jennifer A; Elton, Debra M

    2011-01-10

    Like other influenza A viruses, equine influenza virus undergoes antigenic drift. It is therefore essential that surveillance is carried out to ensure that recommended strains for inclusion in vaccines are kept up to date. Here we report antigenic and genetic characterisation carried out on equine influenza virus strains isolated in North America and Europe over a 2-year period from 2008 to 2009. Nasopharyngeal swabs were taken from equines showing acute clinical signs and submitted to diagnostic laboratories for testing and virus isolation in eggs. The sequence of the HA1 portion of the viral haemagglutinin was determined for each strain. Where possible, sequence was determined directly from swab material as well as from virus isolated in eggs. In Europe, 20 viruses were isolated from 15 sporadic outbreaks and 5 viruses were isolated from North America. All of the European and North American viruses were characterised as members of the Florida sublineage, with similarity to A/eq/Lincolnshire/1/07 (clade 1) or A/eq/Richmond/1/07 (clade 2). Antigenic characterisation by haemagglutination inhibition assay indicated that the two clades could be readily distinguished and there were also at least seven amino acid differences between them. The selection of vaccine strains for 2010 by the expert surveillance panel have taken these differences into account and it is now recommended that representatives of both Florida clade 1 and clade 2 are included in vaccines. PMID:20580170

  4. Structural basis of influenza virus neutralization

    PubMed Central

    Han, Thomas; Marasco, Wayne A.

    2010-01-01

    Although seasonal influenza vaccines play a valuable role in reducing the spread of the virus at the population level, ongoing viral evolution to evade immune responses remains problematic. No current vaccines are likely to elicit enduring protection in the face of emerging and re-emerging influenza viruses that rapidly undergoing antigenic drift. Eliciting broadly cross-neutralizing antibody responses against influenza virus is a crucial goal for seasonal and pandemic influenza vaccine preparation. Recent three-dimensional structure information obtained from crystallization of influenza antigens in complex with neutralizing antibodies (nAbs) have provided a framework for interpreting antibody-based viral neutralization that should aid in the design of vaccine immunogens. Here, we will review current knowledge of the structure-based mechanisms contributing to the neutralization and neutralization escape of influenza viruses. We will also explore the potential for this structure-based approach to overcome the challenge of obtaining the highly desired “universal” influenza vaccine. PMID:21251008

  5. Whole influenza virus vaccine is more immunogenic than split influenza virus vaccine and induces primarily an IgG2a response in BALB/c mice.

    PubMed

    Hovden, A-O; Cox, R J; Haaheim, L R

    2005-07-01

    The aim of this study was to compare the kinetics and the magnitude of the humoral immune response to two different influenza vaccine formulations, whole and split virus vaccines. BALB/c mice were immunized intramuscularly with one or two doses (3 weeks apart) of 7.5, 15 or 30 microg of haemagglutinin of monovalent A/Panama/2007/99 (H3N2) split or whole virus vaccine. The two vaccine formulations induced similar kinetics of the antibody-secreting cells response; however, differences in the magnitude were observed in the spleen and bone marrow. Vaccination with whole virus vaccine generally elicited a quicker and higher neutralizing antibody response, particularly after the first dose of vaccine. The two vaccine formulations gave different immunoglobulin G (IgG) subclass profiles. Split virus vaccine stimulated both IgG1 and IgG2a antibodies suggestive of mixed T-helper 1 (Th1) and Th2 response, whereas whole virus vaccine induced mainly an IgG2a antibody response, which is indicative of a dominant Th1 response. The increased immunogenicity of whole virus vaccine in a naïve population could reduce the vaccine concentration needed to provide protective immunity. PMID:16092921

  6. Isolation and characterization of highly pathogenic avian influenza virus subtype H5N1 from donkeys

    PubMed Central

    2010-01-01

    Background The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences. Methods Nasal swabs were collected from donkeys suffered from respiratory distress. The virus was isolated from the pooled nasal swabs in specific pathogen free embryonated chicken eggs (SPF-ECE). Reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing of both haemagglutingin and neuraminidase were performed. H5 seroconversion was screened using haemagglutination inhibition (HI) assay on 105 donkey serum samples. Results We demonstrated that H5N1 jumped from poultry to another mammalian host; donkeys. Phylogenetic analysis showed that the virus clustered within the lineage of H5N1 from Egypt, closely related to 2009 isolates. It harboured few genetic changes compared to the closely related viruses from avian and humans. The neuraminidase lacks oseltamivir resistant mutations. Interestingly, HI screening for antibodies to H5 haemagglutinins in donkeys revealed high exposure rate. Conclusions These findings extend the host range of the H5N1 influenza virus, possess implications for influenza virus epidemiology and highlight the need for the systematic surveillance of H5N1 in animals in the vicinity of backyard poultry units especially in endemic areas. PMID:20398268

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

    PubMed

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

    2016-08-01

    The introduction of the 2009 pandemic H1N1 (pH1N1) influenza virus in pigs changed the epidemiology of influenza A viruses (IAVs) in swine in Europe and the rest of the world. Previously, three IAV subtypes were found in the European pig population: an avian-like H1N1 and two reassortant H1N2 and H3N2 viruses with human-origin haemagglutinin (HA) and neuraminidase proteins and internal genes of avian decent. These viruses pose antigenically distinct HAs, which allow the retrospective diagnosis of infection in serological investigations. However, cross-reactions between the HA of pH1N1 and the HAs of the other circulating H1 IAVs complicate serological diagnosis. The prevalence of IAVs in Greek swine has been poorly investigated. In this study, we examined and compared haemagglutination inhibition (HI) antibody titres against previously established IAVs and pH1N1 in 908 swine sera from 88 herds, collected before and after the 2009 pandemic. While we confirmed the historic presence of the three IAVs established in European swine, we also found that 4% of the pig sera examined after 2009 had HI antibodies only against the pH1N1 virus. Our results indicate that pH1N1 is circulating in Greek pigs and stress out the importance of a vigorous virological surveillance programme. PMID:26477456

  8. Innate immune evasion strategies of influenza viruses

    PubMed Central

    Hale, Benjamin G; Albrecht, Randy A; García-Sastre, Adolfo

    2010-01-01

    Influenza viruses are globally important human respiratory pathogens. These viruses cause seasonal epidemics and occasional worldwide pandemics, both of which can vary significantly in disease severity. The virulence of a particular influenza virus strain is partly determined by its success in circumventing the host immune response. This article briefly reviews the innate mechanisms that host cells have evolved to resist virus infection, and outlines the plethora of strategies that influenza viruses have developed in order to counteract such powerful defences. The molecular details of this virus–host interplay are summarized, and the ways in which research in this area is being applied to the rational design of protective vaccines and novel antivirals are discussed. PMID:20020828

  9. Epidemiological and Virological Characterization of Influenza B Virus Infections.

    PubMed

    Sharabi, Sivan; Drori, Yaron; Micheli, Michal; Friedman, Nehemya; Orzitzer, Sara; Bassal, Ravit; Glatman-Freedman, Aharona; Shohat, Tamar; Mendelson, Ella; Hindiyeh, Musa; Mandelboim, Michal

    2016-01-01

    While influenza A viruses comprise a heterogeneous group of clinically relevant influenza viruses, influenza B viruses form a more homogeneous cluster, divided mainly into two lineages: Victoria and Yamagata. This divergence has complicated seasonal influenza vaccine design, which traditionally contained two seasonal influenza A virus strains and one influenza B virus strain. We examined the distribution of the two influenza B virus lineages in Israel, between 2011-2014, in hospitalized and in non-hospitalized (community) influenza B virus-infected patients. We showed that influenza B virus infections can lead to hospitalization and demonstrated that during some winter seasons, both influenza B virus lineages circulated simultaneously in Israel. We further show that the influenza B virus Yamagata lineage was dominant, circulating in the county in the last few years of the study period, consistent with the anti-Yamagata influenza B virus antibodies detected in the serum samples of affected individuals residing in Israel in the year 2014. Interestingly, we found that elderly people were particularly vulnerable to Yamagata lineage influenza B virus infections. PMID:27533045

  10. Epidemiological and Virological Characterization of Influenza B Virus Infections

    PubMed Central

    Sharabi, Sivan; Drori, Yaron; Micheli, Michal; Friedman, Nehemya; Orzitzer, Sara; Bassal, Ravit; Glatman-Freedman, Aharona; Shohat, Tamar; Mendelson, Ella; Hindiyeh, Musa; Mandelboim, Michal

    2016-01-01

    While influenza A viruses comprise a heterogeneous group of clinically relevant influenza viruses, influenza B viruses form a more homogeneous cluster, divided mainly into two lineages: Victoria and Yamagata. This divergence has complicated seasonal influenza vaccine design, which traditionally contained two seasonal influenza A virus strains and one influenza B virus strain. We examined the distribution of the two influenza B virus lineages in Israel, between 2011–2014, in hospitalized and in non-hospitalized (community) influenza B virus-infected patients. We showed that influenza B virus infections can lead to hospitalization and demonstrated that during some winter seasons, both influenza B virus lineages circulated simultaneously in Israel. We further show that the influenza B virus Yamagata lineage was dominant, circulating in the county in the last few years of the study period, consistent with the anti-Yamagata influenza B virus antibodies detected in the serum samples of affected individuals residing in Israel in the year 2014. Interestingly, we found that elderly people were particularly vulnerable to Yamagata lineage influenza B virus infections. PMID:27533045

  11. Avian Influenza A (H7N9) Virus

    MedlinePlus

    ... this page: About CDC.gov . Avian Influenza H5 Viruses in the United States Updates and Publications Information ... Humans Examples of Human Infections with Avian Influenza Viruses Outbreaks Health Care and Laboratorian Guidance HPAI A ...

  12. Prevention and Treatment of Avian Influenza A Viruses in People

    MedlinePlus

    ... Research Making a Candidate Vaccine Virus Related Links Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... Button Past Newsletters Prevention and Treatment of Avian Influenza A Viruses in People Language: English Español ...

  13. Transmission of Avian Influenza A Viruses Between Animals and People

    MedlinePlus

    ... many different animals, including ducks, chickens, pigs, whales, horses, and seals. However, certain subtypes of influenza A ... pigs, and H7N7 and H3N8 virus infections of horses. Influenza A viruses that typically infect and transmit ...

  14. DIESEL EXHAUST ENHANCES INFLUENZA VIRUS INFECTIONS IN RESPIRATORY EPITHELIAL CELLS

    EPA Science Inventory

    Several factors, such as age and nutritional status can affect the susceptibility to influenza infections. Moreover, exposure to air pollutants, such as diesel exhaust (DE), has been shown to affect respiratory virus infections in rodent models. Influenza virus primarily infects ...

  15. Influenza Type A Viruses and Subtypes

    MedlinePlus

    ... virus infection of humans, such as with Asian-origin highly pathogenic avian influenza A (H5N1) viruses currently circulating among poultry in Asia and the Middle East have been reported in 16 countries, often resulting in severe pneumonia with approximately 60% ...

  16. Replication and transmission of influenza viruses in Japanese quail

    PubMed Central

    Makarova, Natalia V.; Ozaki, Hiroishi; Kida, Hiroshi; Webster, Robert G.; Perez, Daniel R.

    2015-01-01

    Quail have emerged as a potential intermediate host in the spread of avian influenza A viruses in poultry in Hong Kong. To better understand this possible role, we tested the replication and transmission in quail of influenza A viruses of all 15 HA subtypes. Quail supported the replication of at least 14 subtypes. Influenza A viruses replicated predominantly in the respiratory tract. Transmission experiments suggested that perpetuation of avian influenza viruses in quail requires adaptation. Swine influenza viruses were isolated from the respiratory tract of quail at low levels. There was no evidence of human influenza A or B virus replication. Interestingly, a human–avian recombinant containing the surface glycoprotein genes of a quail virus and the internal genes of a human virus replicated and transmitted readily in quail; therefore, quail could function as amplifiers of influenza virus reassortants that have the potential to infect humans and/or other mammalian species. PMID:12788625

  17. Comparative pathology of select agent influenza A virus infections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A virus infections may spread rapidly in human populations and cause acute respiratory disease with variable mortality. Two of these influenza viruses have been designated as select agents because of the high case fatality rate: 1918 H1N1 virus and highly pathogenic avian influenza (HPAI) ...

  18. WOULD THE 1918 PANDEMIC INFLUENZA VIRUS BE A THREAT TODAY?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 1918 influenza pandemic caused more than 20 million deaths worldwide. Under biosafety level 3Ag containment, a recombinant influenza virus bearing the 1918 influenza virus hemagglutinin (HA) and neuraminidase (NA) was generated. This virus is highly virulent in mice, pointing to the 1918 HA and...

  19. Virological surveillance of influenza and other respiratory viruses during six consecutive seasons from 2006 to 2012 in Catalonia, Spain.

    PubMed

    Antón, A; Marcos, M A; Torner, N; Isanta, R; Camps, M; Martínez, A; Domínguez, A; Jané, M; Jiménez de Anta, M T; Pumarola, T

    2016-06-01

    Most attention is given to seasonal influenza and respiratory syncytial virus outbreaks, but the cumulative burden caused by other respiratory viruses (RV) is not widely considered. The aim of the present study is to describe the circulation of RV in the general population during six consecutive seasons from 2006 to 2012 in Catalonia, Spain. Cell culture, immunofluorescence and PCR-based assays were used for the RV laboratory-confirmation and influenza subtyping. Phylogenetic and molecular characterizations of viral haemagglutinin, partial neuraminidase and matrix 2 proteins were performed from a representative sampling of influenza viruses. A total of 6315 nasopharyngeal samples were collected, of which 64% were laboratory-confirmed, mainly as influenza A viruses and rhinoviruses. Results show the significant burden of viral aetiological agents in acute respiratory infection, particularly in the youngest cases. The study of influenza strains reveals their continuous evolution through either progressive mutations or by segment reassortments. Moreover, the predominant influenza B lineage was different from that included in the recommended vaccine in half of the studied seasons, supporting the formulation and use of a quadrivalent influenza vaccine. Regarding neuraminidase inhibitors resistance, with the exception of the 2007/08 H275Y seasonal A(H1N1) strains, no other circulating influenza strains carrying known resistance genetic markers were found. Moreover, all circulating A(H1N1)pdm09 and A(H3N2) strains finally became genetically resistant to adamantanes. A wide knowledge of the seasonality patterns of the RV in the general population is well-appreciated, but it is a challenge due to the unpredictable circulation of RV, highlighting the value of local and global RV surveillance. PMID:26939538

  20. Respiratory Viruses Other than Influenza Virus: Impact and Therapeutic Advances

    PubMed Central

    Nichols, W. Garrett; Peck Campbell, Angela J.; Boeckh, Michael

    2008-01-01

    Summary: Though several antivirals have been developed and marketed to treat influenza virus infections, the development of antiviral agents with clinical activity against other respiratory viruses has been more problematic. Here we review the epidemiology of respiratory viral infections in immunocompetent and immunocompromised hosts, examine the evidence surrounding the currently available antivirals for respiratory viral infections other than influenza, highlight those that are in the pipeline, and discuss the hurdles for development of such agents. PMID:18400797

  1. Isolation of ortho- and paramyxoviruses from wild birds in Western Australia, and the characterization of novel influenza A viruses.

    PubMed

    Mackenzie, J S; Edwards, E C; Holmes, R M; Hinshaw, V S

    1984-02-01

    As part of the World Health Organization's international programme on the ecology of influenza, cloacal swabs were collected from 3,736 birds belonging to 67 species over a 3-year period in Western Australia for the isolation of ortho- and paramyxoviruses. A total of 24 influenza A viruses were isolated from various species of ducks, shearwaters , noddies , terns and a coot , and were subtyped as H1N9 , H3N8 , H4N4 , H4N6 , H6N2 , H6N4 , H?N2, H?N6 and H? N9 . The H? haemagglutinins did not react in tests with reference antisera. Whether they represent a novel haemagglutinin subtype or atypical members of an established subtype remains to be determined, although preliminary results indicate that they may be atypical members of the H7 subtype. The H1N9 isolate is the first reported isolate of this particular antigenic combination. A total of 17 Newcastle disease viruses was isolated from ducks, noddies , terns and a black- fronted plover : preliminary results suggest that they are avirulent for domestic chickens. This study indicates that ortho- and paramyxoviruses are present in a variety of wild birds in Australia. PMID:6430260

  2. Cross-neutralization of influenza A viruses mediated by a single antibody loop.

    PubMed

    Ekiert, Damian C; Kashyap, Arun K; Steel, John; Rubrum, Adam; Bhabha, Gira; Khayat, Reza; Lee, Jeong Hyun; Dillon, Michael A; O'Neil, Ryann E; Faynboym, Aleksandr M; Horowitz, Michael; Horowitz, Lawrence; Ward, Andrew B; Palese, Peter; Webby, Richard; Lerner, Richard A; Bhatt, Ramesh R; Wilson, Ian A

    2012-09-27

    Immune recognition of protein antigens relies on the combined interaction of multiple antibody loops, which provide a fairly large footprint and constrain the size and shape of protein surfaces that can be targeted. Single protein loops can mediate extremely high-affinity binding, but it is unclear whether such a mechanism is available to antibodies. Here we report the isolation and characterization of an antibody called C05, which neutralizes strains from multiple subtypes of influenza A virus, including H1, H2 and H3. X-ray and electron microscopy structures show that C05 recognizes conserved elements of the receptor-binding site on the haemagglutinin surface glycoprotein. Recognition of the haemagglutinin receptor-binding site is dominated by a single heavy-chain complementarity-determining region 3 loop, with minor contacts from heavy-chain complementarity-determining region 1, and is sufficient to achieve nanomolar binding with a minimal footprint. Thus, binding predominantly with a single loop can allow antibodies to target small, conserved functional sites on otherwise hypervariable antigens. PMID:22982990

  3. Broadly neutralizing antibodies against influenza viruses

    PubMed Central

    Laursen, Nick S.; Wilson, Ian A.

    2014-01-01

    Despite available antivirals and vaccines, influenza infections continue to be a major cause of mortality worldwide. Vaccination generally induces an effective, but strain-specific antibody response. As the virus continually evolves, new vaccines have to be administered almost annually when a novel strain becomes dominant. Furthermore, the sporadic emerging resistance to neuraminidase inhibitors among circulating strains suggests an urgent need for new therapeutic agents. Recently, several cross-reactive antibodies have been described, which neutralize an unprecedented spectrum of influenza viruses. These broadly neutralizing antibodies generally target conserved functional regions on the major influenza surface glycoprotein hemagglutinin (HA). The characterization of their neutralization breadth and epitopes on HA could stimulate the development of new antibody-based antivirals and broader influenza vaccines. PMID:23583287

  4. Influenza Virus Propagation in Embryonated Chicken Eggs

    PubMed Central

    Brauer, Rena; Chen, Peter

    2015-01-01

    Influenza infection is associated with about 36,000 deaths and more than 200,000 hospitalizations every year in the United States. The continuous emergence of new influenza virus strains due to mutation and re-assortment complicates the control of the virus and necessitates the permanent development of novel drugs and vaccines. The laboratory-based study of influenza requires a reliable and cost-effective method for the propagation of the virus. Here, a comprehensive protocol is provided for influenza A virus propagation in fertile chicken eggs, which consistently yields high titer viral stocks. In brief, serum pathogen-free (SPF) fertilized chicken eggs are incubated at 37 °C and 55-60% humidity for 10 – 11 days. Over this period, embryo development can be easily monitored using an egg candler. Virus inoculation is carried out by injection of virus stock into the allantoic cavity using a needle. After 2 days of incubation at 37 °C, the eggs are chilled for at least 4 hr at 4 °C. The eggshell above the air sac and the chorioallantoic membrane are then carefully opened, and the allantoic fluid containing the virus is harvested. The fluid is cleared from debris by centrifugation, aliquoted and transferred to -80 °C for long-term storage. The large amount (5-10 ml of virus-containing fluid per egg) and high virus titer which is usually achieved with this protocol has made the usage of eggs for virus preparation our favorable method, in particular for in vitro studies which require large quantities of virus in which high dosages of the same virus stock are needed. PMID:25867050

  5. Influenza virus propagation in embryonated chicken eggs.

    PubMed

    Brauer, Rena; Chen, Peter

    2015-01-01

    Influenza infection is associated with about 36,000 deaths and more than 200,000 hospitalizations every year in the United States. The continuous emergence of new influenza virus strains due to mutation and re-assortment complicates the control of the virus and necessitates the permanent development of novel drugs and vaccines. The laboratory-based study of influenza requires a reliable and cost-effective method for the propagation of the virus. Here, a comprehensive protocol is provided for influenza A virus propagation in fertile chicken eggs, which consistently yields high titer viral stocks. In brief, serum pathogen-free (SPF) fertilized chicken eggs are incubated at 37 °C and 55-60% humidity for 10-11 days. Over this period, embryo development can be easily monitored using an egg candler. Virus inoculation is carried out by injection of virus stock into the allantoic cavity using a needle. After 2 days of incubation at 37 °C, the eggs are chilled for at least 4 hr at 4 °C. The eggshell above the air sac and the chorioallantoic membrane are then carefully opened, and the allantoic fluid containing the virus is harvested. The fluid is cleared from debris by centrifugation, aliquoted and transferred to -80 °C for long-term storage. The large amount (5-10 ml of virus-containing fluid per egg) and high virus titer which is usually achieved with this protocol has made the usage of eggs for virus preparation our favorable method, in particular for in vitro studies which require large quantities of virus in which high dosages of the same virus stock are needed. PMID:25867050

  6. Isolation and genetic characterization of influenza A viruses and a paramyxovirus from wild birds in Barbados: 2003-2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 haemagglutinin (HA) and 9 neuraminidase (NA) influenza subtypes have been isola...

  7. Nasal commensal Staphylococcus epidermidis counteracts influenza virus

    PubMed Central

    Chen, Hui-Wen; Liu, Pei-Feng; Liu, Yu-Tsueng; Kuo, Sherwin; Zhang, Xing-Quan; Schooley, Robert T.; Rohde, Holger; Gallo, Richard L.; Huang, Chun-Ming

    2016-01-01

    Several microbes, including Staphylococcus epidermidis (S. epidermidis), a Gram-positive bacterium, live inside the human nasal cavity as commensals. The role of these nasal commensals in host innate immunity is largely unknown, although bacterial interference in the nasal microbiome may promote ecological competition between commensal bacteria and pathogenic species. We demonstrate here that S. epidermidis culture supernatants significantly suppressed the infectivity of various influenza viruses. Using high-performance liquid chromatography together with mass spectrometry, we identified a giant extracellular matrix-binding protein (Embp) as the major component involved in the anti-influenza effect of S. epidermidis. This anti-influenza activity was abrogated when Embp was mutated, confirming that Embp is essential for S. epidermidis activity against viral infection. We also showed that both S. epidermidis bacterial particles and Embp can directly bind to influenza virus. Furthermore, the injection of a recombinant Embp fragment containing a fibronectin-binding domain into embryonated eggs increased the survival rate of virus-infected chicken embryos. For an in vivo challenge study, prior Embp intranasal inoculation in chickens suppressed the viral titres and induced the expression of antiviral cytokines in the nasal tissues. These results suggest that S. epidermidis in the nasal cavity may serve as a defence mechanism against influenza virus infection. PMID:27306590

  8. Setting up a platform for plant-based influenza virus vaccine production in South Africa

    PubMed Central

    2012-01-01

    Background During a global influenza pandemic, the vaccine requirements of developing countries can surpass their supply capabilities, if these exist at all, compelling them to rely on developed countries for stocks that may not be available in time. There is thus a need for developing countries in general to produce their own pandemic and possibly seasonal influenza vaccines. Here we describe the development of a plant-based platform for producing influenza vaccines locally, in South Africa. Plant-produced influenza vaccine candidates are quicker to develop and potentially cheaper than egg-produced influenza vaccines, and their production can be rapidly upscaled. In this study, we investigated the feasibility of producing a vaccine to the highly pathogenic avian influenza A subtype H5N1 virus, the most generally virulent influenza virus identified to date. Two variants of the haemagglutinin (HA) surface glycoprotein gene were synthesised for optimum expression in plants: these were the full-length HA gene (H5) and a truncated form lacking the transmembrane domain (H5tr). The genes were cloned into a panel of Agrobacterium tumefaciens binary plant expression vectors in order to test HA accumulation in different cell compartments. The constructs were transiently expressed in tobacco by means of agroinfiltration. Stable transgenic tobacco plants were also generated to provide seed for stable storage of the material as a pre-pandemic strategy. Results For both transient and transgenic expression systems the highest accumulation of full-length H5 protein occurred in the apoplastic spaces, while the highest accumulation of H5tr was in the endoplasmic reticulum. The H5 proteins were produced at relatively high concentrations in both systems. Following partial purification, haemagglutination and haemagglutination inhibition tests indicated that the conformation of the plant-produced HA variants was correct and the proteins were functional. The immunisation of chickens and

  9. Genetic and antigenic characterization of H1 influenza viruses from United States swine from 2008

    PubMed Central

    Lorusso, Alessio; Vincent, Amy L.; Harland, Michelle L.; Alt, David; Bayles, Darrell O.; Swenson, Sabrina L.; Gramer, Marie R.; Russell, Colin A.; Smith, Derek J.; Lager, Kelly M.; Lewis, Nicola S.

    2011-01-01

    Prior to the introduction of the 2009 pandemic H1N1 virus from humans into pigs, four phylogenetic clusters (α-, β-, γ- and δ) of the haemagglutinin (HA) gene from H1 influenza viruses could be found in US swine. Information regarding the antigenic relatedness of the H1 viruses was lacking due to the dynamic and variable nature of swine lineage H1. We characterized 12 H1 isolates from 2008 by using 454 genome-sequencing technology and phylogenetic analysis of all eight gene segments and by serological cross-reactivity in the haemagglutination inhibition (HI) assay. Genetic diversity was demonstrated in all gene segments, but most notably in the HA gene. The gene segments from the 2009 pandemic H1N1 formed clusters separate from North American swine lineage viruses, suggesting progenitors of the pandemic virus were not present in US pigs immediately prior to 2009. Serological cross-reactivity paired with antigenic cartography demonstrated that the viruses in the different phylogenetic clusters are also antigenically divergent. PMID:21177926

  10. Phenotypic and genotypic characterization of influenza virus mutants selected with the sialidase fusion protein DAS181

    PubMed Central

    Triana-Baltzer, Gallen B.; Sanders, Rebecca L.; Hedlund, Maria; Jensen, Kellie A.; Aschenbrenner, Laura M.; Larson, Jeffrey L.; Fang, Fang

    2011-01-01

    Background Influenza viruses (IFVs) frequently achieve resistance to antiviral drugs, necessitating the development of compounds with novel mechanisms of action. DAS181 (Fludase®), a sialidase fusion protein, may have a reduced potential for generating drug resistance due to its novel host-targeting mechanism of action. Methods IFV strains B/Maryland/1/59 and A/Victoria/3/75 (H3N2) were subjected to >30 passages under increasing selective pressure with DAS181. The DAS181-selected IFV isolates were characterized in vitro and in mice. Results Despite extensive passaging, DAS181-selected viruses exhibited a very low level of resistance to DAS181, which ranged between 3- and 18-fold increase in EC50. DAS181-selected viruses displayed an attenuated phenotype in vitro, as exhibited by slower growth, smaller plaque size and increased particle to pfu ratios relative to wild-type virus. Further, the DAS181 resistance phenotype was unstable and was substantially reversed over time upon DAS181 withdrawal. In mice, the DAS181-selected viruses exhibited no greater virulence than their wild-type counterparts. Genotypic and phenotypic analysis of DAS181-selected viruses revealed mutations in the haemagglutinin (HA) and neuraminidase (NA) molecules and also changes in HA and NA function. Conclusions Results indicate that resistance to DAS181 is minimal and unstable. The DAS181-selected IFV isolates exhibit reduced fitness in vitro, likely due to altered HA and NA functions. PMID:21097900

  11. Epidemiological and Evolutionary Dynamics of Influenza B Viruses in Malaysia, 2012-2014.

    PubMed

    Oong, Xiang Yong; Ng, Kim Tien; Lam, Tommy Tsan-Yuk; Pang, Yong Kek; Chan, Kok Gan; Hanafi, Nik Sherina; Kamarulzaman, Adeeba; Tee, Kok Keng

    2015-01-01

    Epidemiological and evolutionary dynamics of influenza B Victoria and Yamagata lineages remained poorly understood in the tropical Southeast Asia region, despite causing seasonal outbreaks worldwide. From 2012-2014, nasopharyngeal swab samples collected from outpatients experiencing acute upper respiratory tract infection symptoms in Kuala Lumpur, Malaysia, were screened for influenza viruses using a multiplex RT-PCR assay. Among 2,010/3,935 (51.1%) patients infected with at least one respiratory virus, 287 (14.3%) and 183 (9.1%) samples were tested positive for influenza A and B viruses, respectively. Influenza-positive cases correlate significantly with meteorological factors-total amount of rainfall, relative humidity, number of rain days, ground temperature and particulate matter (PM10). Phylogenetic reconstruction of haemagglutinin (HA) gene from 168 influenza B viruses grouped them into Yamagata Clade 3 (65, 38.7%), Yamagata Clade 2 (48, 28.6%) and Victoria Clade 1 (55, 32.7%). With neuraminidase (NA) phylogeny, 30 intra-clade (29 within Yamagata Clade 3, 1 within Victoria Clade 1) and 1 inter-clade (Yamagata Clade 2-HA/Yamagata Clade 3-NA) reassortants were identified. Study of virus temporal dynamics revealed a lineage shift from Victoria to Yamagata (2012-2013), and a clade shift from Yamagata Clade 2 to Clade 3 (2013-2014). Yamagata Clade 3 predominating in 2014 consisted of intra-clade reassortants that were closely related to a recent WHO vaccine candidate strain (B/Phuket/3073/2013), with the reassortment event occurred approximately 2 years ago based on Bayesian molecular clock estimation. Malaysian Victoria Clade 1 viruses carried H274Y substitution in the active site of neuraminidase, which confers resistance to oseltamivir. Statistical analyses on clinical and demographic data showed Yamagata-infected patients were older and more likely to experience headache while Victoria-infected patients were more likely to experience nasal congestion and sore

  12. Epidemiological and Evolutionary Dynamics of Influenza B Viruses in Malaysia, 2012-2014

    PubMed Central

    Pang, Yong Kek; Chan, Kok Gan; Hanafi, Nik Sherina; Kamarulzaman, Adeeba; Tee, Kok Keng

    2015-01-01

    Epidemiological and evolutionary dynamics of influenza B Victoria and Yamagata lineages remained poorly understood in the tropical Southeast Asia region, despite causing seasonal outbreaks worldwide. From 2012–2014, nasopharyngeal swab samples collected from outpatients experiencing acute upper respiratory tract infection symptoms in Kuala Lumpur, Malaysia, were screened for influenza viruses using a multiplex RT-PCR assay. Among 2,010/3,935 (51.1%) patients infected with at least one respiratory virus, 287 (14.3%) and 183 (9.1%) samples were tested positive for influenza A and B viruses, respectively. Influenza-positive cases correlate significantly with meteorological factors—total amount of rainfall, relative humidity, number of rain days, ground temperature and particulate matter (PM10). Phylogenetic reconstruction of haemagglutinin (HA) gene from 168 influenza B viruses grouped them into Yamagata Clade 3 (65, 38.7%), Yamagata Clade 2 (48, 28.6%) and Victoria Clade 1 (55, 32.7%). With neuraminidase (NA) phylogeny, 30 intra-clade (29 within Yamagata Clade 3, 1 within Victoria Clade 1) and 1 inter-clade (Yamagata Clade 2-HA/Yamagata Clade 3-NA) reassortants were identified. Study of virus temporal dynamics revealed a lineage shift from Victoria to Yamagata (2012–2013), and a clade shift from Yamagata Clade 2 to Clade 3 (2013–2014). Yamagata Clade 3 predominating in 2014 consisted of intra-clade reassortants that were closely related to a recent WHO vaccine candidate strain (B/Phuket/3073/2013), with the reassortment event occurred approximately 2 years ago based on Bayesian molecular clock estimation. Malaysian Victoria Clade 1 viruses carried H274Y substitution in the active site of neuraminidase, which confers resistance to oseltamivir. Statistical analyses on clinical and demographic data showed Yamagata-infected patients were older and more likely to experience headache while Victoria-infected patients were more likely to experience nasal congestion

  13. Bat and pig IFN-induced transmembrane protein 3 restrict cell entry by influenza virus and lyssaviruses

    PubMed Central

    Smith, Sarah E.; Wright, Edward; Wash, Rachael S.; Ferrara, Francesca; Temperton, Nigel J.; Kellam, Paul

    2015-01-01

    IFN-induced transmembrane protein 3 (IFITM3) is a restriction factor that blocks cytosolic entry of numerous viruses that utilize acidic endosomal entry pathways. In humans and mice, IFITM3 limits influenza-induced morbidity and mortality. Although many IFITM3-sensitive viruses are zoonotic, whether IFITMs function as antiviral restriction factors in mammalian species other than humans and mice is unknown. Here, IFITM3 orthologues in the microbat (Myotis myotis) and pig (Sus scrofa domesticus) were identified using rapid amplification of cDNA ends. Amino acid residues known to be important for IFITM3 function were conserved in the pig and microbat orthologues. Ectopically expressed pig and microbat IFITM3 co-localized with transferrin (early endosomes) and CD63 (late endosomes/multivesicular bodies). Pig and microbat IFITM3 restricted cell entry mediated by multiple influenza haemagglutinin subtypes and lyssavirus glycoproteins. Expression of pig or microbat IFITM3 in A549 cells reduced influenza virus yields and nucleoprotein expression. Conversely, small interfering RNA knockdown of IFITM3 in pig NPTr cells and primary microbat cells enhanced virus replication, demonstrating that these genes are functional in their species of origin at endogenous levels. In summary, we showed that IFITMs function as potent broad-spectrum antiviral effectors in two mammals – pigs and bats – identified as major reservoirs for emerging viruses. PMID:25614588

  14. Ambient Influenza and Avian Influenza Virus during Dust Storm Days and Background Days

    PubMed Central

    Chen, Pei-Shih; Tsai, Feng Ta; Lin, Chien Kun; Yang, Chun-Yuh; Chan, Chang-Chuan; Young, Chea-Yuan; Lee, Chien-Hung

    2010-01-01

    Background The spread of influenza and highly pathogenic avian influenza (H5N1) presents a significant threat to human health. Avian influenza outbreaks in downwind areas of Asian dust storms (ADS) suggest that viruses might be transported by dust storms. Objectives We developed a technique to measure ambient influenza and avian influenza viruses. We then used this technique to measure concentrations of these viruses on ADS days and background days, and to assess the relationships between ambient influenza and avian influenza viruses, and air pollutants. Methods A high-volume air sampler was used in parallel with a filter cassette to evaluate spiked samples and unspiked samples. Then, air samples were monitored during ADS seasons using a filter cassette coupled with a real-time quantitative polymerase chain reaction (qPCR) assay. Air samples were monitored during ADS season (1 January to 31 May 2006). Results We successfully quantified ambient influenza virus using the filtration/real-time qPCR method during ADS days and background days. To our knowledge, this is the first report describing the concentration of influenza virus in ambient air. In both the spiked and unspiked samples, the concentration of influenza virus sampled using the filter cassette was higher than that using the high-volume sampler. The concentration of ambient influenza A virus was significantly higher during the ADS days than during the background days. Conclusions Our data imply the possibility of long-range transport of influenza virus. PMID:20435545

  15. Influenza viruses in birds: rapid identification by counterimmunoelectrophoresis.

    PubMed Central

    Lecomte, J; Berthiaume, L; Boudreault, A

    1979-01-01

    Counterimmunoelectrophoresis with an antiserum raised in rabbits against the M protein of the avian N virus proved to be particularly useful for large-scale identification of influenza A virus isolates. Of a total of 231 hemagglutinating agents isolated from 1,656 rectal swabs collected from shore and open-country birds, 158 could be identified as influenza A viruses by counterimmunoelectrophoresis, and 75 were serologically related to Newcastle disease virus by hemagglutination inhibition with an antiserum to Newcastle disease virus. Two isolates contained a mixture of influenza A virus and Newcastle disease virus; although the Newcastle disease virus virus particles outnumbered the influenza A virus particles in a ratio of 1,000:1, as seen by electron microscopy, the latter could be readily detected by counterimmunoelectrophoresis. This type of assay appears to be of potential use for epidemiological surveillance of influenza virus isolated from humans and animals. It combines specificity, sensitivity, and simplicity. Images PMID:85632

  16. Directed selection of influenza virus produces antigenic variants that match circulating human virus isolates and escape from vaccine-mediated immune protection.

    PubMed

    DeDiego, Marta L; Anderson, Christopher S; Yang, Hongmei; Holden-Wiltse, Jeanne; Fitzgerald, Theresa; Treanor, John J; Topham, David J

    2016-06-01

    Influenza vaccination does not provide 100% protection from infection, partly due to antigenic drift of the haemagglutinin (HA) protein. Low serum antibody titres increase the risk of infection. To determine whether there were additional correlates of risk, we examined the relationship between human serum immunity and antigenic variation in seasonal H3N2 influenza viruses. Seasonal H3N2 vaccine strains grown in the presence of heterogeneous human or mono-specific ferret antisera selected variants with mutations in the HA antigenic sites. Surprisingly, circulating strains infecting human subjects in the same seasons displayed mutations in the same positions, although only in one case did the change correspond to the same amino acid. Serum antibody titres were lower against both the in vitro selected and clinical isolates compared with the vaccine strains, suggesting that the mutations are relevant to vaccine failure. Antibody titres were also significantly lower in sera from infected subjects than in non-infected subjects, suggesting relatively poor responses to vaccination in the infected subjects. Collectively, the data suggest that risk from influenza infection is a result of poor response to vaccination, as well as encounter with drifted seasonal influenza virus antigenic variants. The results also show that directed selection under human immune pressure could reveal antigenic variants relevant to real-world drifted viruses, helping in annual vaccine re-formulation. PMID:26854888

  17. Enhanced human receptor binding by H5 haemagglutinins.

    PubMed

    Xiong, Xiaoli; Xiao, Haixia; Martin, Stephen R; Coombs, Peter J; Liu, Junfeng; Collins, Patrick J; Vachieri, Sebastien G; Walker, Philip A; Lin, Yi Pu; McCauley, John W; Gamblin, Steven J; Skehel, John J

    2014-05-01

    Mutant H5N1 influenza viruses have been isolated from humans that have increased human receptor avidity. We have compared the receptor binding properties of these mutants with those of wild-type viruses, and determined the structures of their haemagglutinins in complex with receptor analogues. Mutants from Vietnam bind tighter to human receptor by acquiring basic residues near the receptor binding site. They bind more weakly to avian receptor because they lack specific interactions between Asn-186 and Gln-226. In contrast, a double mutant, Δ133/Ile155Thr, isolated in Egypt has greater avidity for human receptor while retaining wild-type avidity for avian receptor. Despite these increases in human receptor binding, none of the mutants prefers human receptor, unlike aerosol transmissible H5N1 viruses. Nevertheless, mutants with high avidity for both human and avian receptors may be intermediates in the evolution of H5N1 viruses that could infect both humans and poultry. PMID:24889237

  18. Enhanced human receptor binding by H5 haemagglutinins

    PubMed Central

    Xiong, Xiaoli; Xiao, Haixia; Martin, Stephen R.; Coombs, Peter J.; Liu, Junfeng; Collins, Patrick J.; Vachieri, Sebastien G.; Walker, Philip A.; Lin, Yi Pu; McCauley, John W.; Gamblin, Steven J.; Skehel, John J.

    2014-01-01

    Mutant H5N1 influenza viruses have been isolated from humans that have increased human receptor avidity. We have compared the receptor binding properties of these mutants with those of wild-type viruses, and determined the structures of their haemagglutinins in complex with receptor analogues. Mutants from Vietnam bind tighter to human receptor by acquiring basic residues near the receptor binding site. They bind more weakly to avian receptor because they lack specific interactions between Asn-186 and Gln-226. In contrast, a double mutant, Δ133/Ile155Thr, isolated in Egypt has greater avidity for human receptor while retaining wild-type avidity for avian receptor. Despite these increases in human receptor binding, none of the mutants prefers human receptor, unlike aerosol transmissible H5N1 viruses. Nevertheless, mutants with high avidity for both human and avian receptors may be intermediates in the evolution of H5N1 viruses that could infect both humans and poultry. PMID:24889237

  19. THE MOLECULAR BIOLOGY OF AVIAN INFLUENZA VIRUS IN SHORT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) is an important pathogen of poultry as it can cause severe economic losses through disease, including respiratory signs and mortality, and effects on trade. Avian influenza virus is classified as type A influenza, which is a member of the orthomyxoviridae family. Charact...

  20. Swine as a model for influenza A virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A viruses (IAV) infect a variety of hosts, including humans, swine, and various avian species. The annual influenza disease burden in the human population remains significant even with current vaccine usage and much about the pathogenesis and transmission of influenza viruses in human rema...

  1. KINETIC PROFILE OF INFLUENZA VIRUS INFECTION IN THREE RAT STRAINS

    EPA Science Inventory

    Abstract

    Influenza infection is a respiratory disease of viral origin that can cause major epidemics in man. The influenza virus infects and damages epithelial cells of the respiratory tract and causes pneumonia. Lung lesions of mice infected with influenza virus resembl...

  2. Interaction of nanodiamonds materials with influenza viruses

    NASA Astrophysics Data System (ADS)

    Ivanova, V. T.; Ivanova, M. V.; Spitsyn, B. V.; Garina, K. O.; Trushakova, S. V.; Manykin, A. A.; Korzhenevsky, A. P.; Burseva, E. I.

    2012-02-01

    The perspectives of the application of modern materials contained nanodiamonds (ND) are considered in this study. The interaction between detonation paniculate ND, soot and influenza A and B viruses, fragments of cDNA were analyzed at the normal conditions. It was shown that these sorbents can interact with the following viruses: reference epidemic strains of influenza A(H1N1), A(H1N1)v, A(H3N2) and B viruses circulated in the word in 2000-2010. The allantoises, concentrated viruses, cDNA can be absorbed by ND sorbents and getting removed from water solutions within 20 min. ND sorbents can be used for the preparation of antivirus filters for water solution and for future diagnostic systems in virology.

  3. Protective effects of phillyrin against influenza A virus in vivo.

    PubMed

    Qu, Xin-Yan; Li, Qing-Jun; Zhang, Hui-Min; Zhang, Xiao-Juan; Shi, Peng-Hui; Zhang, Xiu-Juan; Yang, Jing; Zhou, Zhe; Wang, Sheng-Qi

    2016-07-01

    Influenza A virus infection represents a great threat to public health. However, owing to side effects and the emergence of resistant virus strains, the use of currently available anti-influenza drugs may be limited. In order to identify novel anti-influenza drugs, we investigated the antiviral effects of phillyrin against influenza A virus infection in vivo. The mean survival time, lung index, viral titers, influenza hemagglutinin (HA) protein and serum cytokines levels, and histopathological changes in lung tissue were examined. Administration of phillyrin at a dose of 20 mg/kg/day for 3 days significantly prolonged the mean survival time, reduced the lung index, decreased the virus titers and interleukin-6 levels, reduced the expression of HA, and attenuated lung tissue damage in mice infected with influenza A virus. Taken together, these data showed that phillyrin had potential protective effects against infection caused by influenza A virus. PMID:27323762

  4. The changing face of swine influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    "Flu" in pigs has been known for 90 years and on the surface it may appear as though little has changed. We still suspect flu when a high percentage of pigs have a sudden onset of barking cough, especially during temperature fluctuations in the fall or spring. However, the influenza viruses responsi...

  5. Effects of egg-adaptation on receptor-binding and antigenic properties of recent influenza A (H3N2) vaccine viruses.

    PubMed

    Parker, Lauren; Wharton, Stephen A; Martin, Stephen R; Cross, Karen; Lin, Yipu; Liu, Yan; Feizi, Ten; Daniels, Rodney S; McCauley, John W

    2016-06-01

    Influenza A virus (subtype H3N2) causes seasonal human influenza and is included as a component of influenza vaccines. The majority of vaccine viruses are isolated and propagated in eggs, which commonly results in amino acid substitutions in the haemagglutinin (HA) glycoprotein. These substitutions can affect virus receptor-binding and alter virus antigenicity, thereby, obfuscating the choice of egg-propagated viruses for development into candidate vaccine viruses. To evaluate the effects of egg-adaptive substitutions seen in H3N2 vaccine viruses on sialic acid receptor-binding, we carried out quantitative measurement of virus receptor-binding using surface biolayer interferometry with haemagglutination inhibition (HI) assays to correlate changes in receptor avidity with antigenic properties. Included in these studies was a panel of H3N2 viruses generated by reverse genetics containing substitutions seen in recent egg-propagated vaccine viruses and corresponding cell culture-propagated wild-type viruses. These assays provide a quantitative approach to investigating the importance of individual amino acid substitutions in influenza receptor-binding. Results show that viruses with egg-adaptive HA substitutions R156Q, S219Y, and I226N, have increased binding avidity to α2,3-linked receptor-analogues and decreased binding avidity to α2,6-linked receptor-analogues. No measurable binding was detected for the viruses with amino acid substitution combination 156Q+219Y and receptor-binding increased in viruses where egg-adaptation mutations were introduced into cell culture-propagated virus. Substitutions at positions 156 and 190 appeared to be primarily responsible for low reactivity in HI assays with post-infection ferret antisera raised against 2012-2013 season H3N2 viruses. Egg-adaptive substitutions at position 186 caused substantial differences in binding avidity with an insignificant effect on antigenicity. PMID:26974849

  6. Promoter analysis of influenza virus RNA polymerase.

    PubMed Central

    Parvin, J D; Palese, P; Honda, A; Ishihama, A; Krystal, M

    1989-01-01

    Influenza virus polymerase, which was prepared depleted of viral RNA, was used to copy small RNA templates prepared from plasmid-encoded sequences. Template constructions containing only the 3' end of genomic RNA were shown to be efficiently copied, indicating that the promoter lay solely within the 15-nucleotide 3' terminus. Sequences not specific for the influenza virus termini were not copied, and, surprisingly, RNAs containing termini identical to those from plus-sense cRNA were copied at low levels. The specificity for recognition of the virus sense promoter was further defined by site-specific mutagenesis. It was also found that increased levels of viral protein were required in order to catalyze both the cap endonuclease-primed and primer-free RNA synthesis from these model templates, as well as from genomic-length RNAs. This finding indicates that the reconstituted system has catalytic properties very similar to those of native viral ribonucleoprotein complexes. Images PMID:2585601

  7. Influenza Virus Evolution, Host Adaptation and Pandemic Formation

    PubMed Central

    Taubenberger, Jeffery K.; Kash, John C.

    2010-01-01

    Newly emerging or `re-emerging' viral diseases continue to pose significant global public health threats. Prototypic are influenza viruses that are major causes of human respiratory infections and mortality. Influenza viruses can cause zoonotic infections and adapt to humans leading to sustained transmission and emergence of novel viruses. Mechanisms by which viruses evolve in one host, cause zoonotic infection and adapt to a new host species remain unelucidated. Here we review evolution of influenza A viruses in their reservoir hosts and discuss genetic changes associated with introduction of novel viruses into humans leading to pandemics and the establishment of seasonal viruses. PMID:20542248

  8. Equine influenza outbreak in India (2008-09): virus isolation, sero-epidemiology and phylogenetic analysis of HA gene.

    PubMed

    Virmani, Nitin; Bera, B C; Singh, B K; Shanmugasundaram, K; Gulati, B R; Barua, Sanjay; Vaid, R K; Gupta, A K; Singh, R K

    2010-07-14

    An outbreak of equine influenza (EI) was reported in India in June, 2008 after a gap of two decades. The outbreak started from Jammu and Kashmir (Katra), northern state of India and spread to the other parts of the country affecting equines in 11 states. The virus (H3N8) was isolated from nasal swabs obtained from clinical cases in various locations in the country including Katra (Jammu and Kashmir), Mysore (Karnataka) and Ahmedabad (Gujarat) using embryonated chicken eggs. The virus isolates were identified as H3N8 by haemagglutination inhibition (HI) test titration with standard serum and by sequencing of full-length haemagglutinin (HA) gene and partial sequence of neuraminidase (NA) gene. Paired serum samples (n=271) showing more than fourfold rise in antibody titres tested from 11 states confirmed equine influenza. Serum samples (n=2517) of equines from 13 states of the country screened by HI test revealed 687 (26.85%) samples positive for antibodies to EI (H3N8). Phylogenetic analysis of the haemagglutinin (HA) gene confirmed the virus to be closely related to Clade 2 of the Florida sublineage in American lineage. Comparison of deduced amino acid sequence of HA gene with EIV isolates from various lineages showed substitutions in the antigenic regions C and D. HA1 gene sequence had highest amino acid identity to A/eq/Gansu/7/08 and A/eq/Hubei/6/08 isolates from China and Inner-Mongolia isolate, while the complete HA gene sequence was closest to A/eq/A/eq/Newmarket/5/03, A/eq/Bari/05 and A/eq/Kentucky/05/02 isolates. Recent outbreaks of Mongolia, China and India by clade 2 EI viruses imply their predominance in Asia in addition to Europe. PMID:20053509

  9. Swine influenza virus: zoonotic potential and vaccination strategies for the control of avian and swine influenzas.

    PubMed

    Thacker, Eileen; Janke, Bruce

    2008-02-15

    Influenza viruses are able to infect humans, swine, and avian species, and swine have long been considered a potential source of new influenza viruses that can infect humans. Swine have receptors to which both avian and mammalian influenza viruses bind, which increases the potential for viruses to exchange genetic sequences and produce new reassortant viruses in swine. A number of genetically diverse viruses are circulating in swine herds throughout the world and are a major cause of concern to the swine industry. Control of swine influenza is primarily through the vaccination of sows, to protect young pigs through maternally derived antibodies. However, influenza viruses continue to circulate in pigs after the decay of maternal antibodies, providing a continuing source of virus on a herd basis. Measures to control avian influenza in commercial poultry operations are dictated by the virulence of the virus. Detection of a highly pathogenic avian influenza (HPAI) virus results in immediate elimination of the flock. Low-pathogenic avian influenza viruses are controlled through vaccination, which is done primarily in turkey flocks. Maintenance of the current HPAI virus-free status of poultry in the United States is through constant surveillance of poultry flocks. Although current influenza vaccines for poultry and swine are inactivated and adjuvanted, ongoing research into the development of newer vaccines, such as DNA, live-virus, or vectored vaccines, is being done. Control of influenza virus infection in poultry and swine is critical to the reduction of potential cross-species adaptation and spread of influenza viruses, which will minimize the risk of animals being the source of the next pandemic. PMID:18269323

  10. Origin of the European avian-like swine influenza viruses.

    PubMed

    Krumbholz, Andi; Lange, Jeannette; Sauerbrei, Andreas; Groth, Marco; Platzer, Matthias; Kanrai, Pumaree; Pleschka, Stephan; Scholtissek, Christoph; Büttner, Mathias; Dürrwald, Ralf; Zell, Roland

    2014-11-01

    The avian-like swine influenza viruses emerged in 1979 in Belgium and Germany. Thereafter, they spread through many European swine-producing countries, replaced the circulating classical swine H1N1 influenza viruses, and became endemic. Serological and subsequent molecular data indicated an avian source, but details remained obscure due to a lack of relevant avian influenza virus sequence data. Here, the origin of the European avian-like swine influenza viruses was analysed using a collection of 16 European swine H1N1 influenza viruses sampled in 1979-1981 in Germany, the Netherlands, Belgium, Italy and France, as well as several contemporaneous avian influenza viruses of various serotypes. The phylogenetic trees suggested a triple reassortant with a unique genotype constellation. Time-resolved maximum clade credibility trees indicated times to the most recent common ancestors of 34-46 years (before 2008) depending on the RNA segment and the method of tree inference. PMID:25073465

  11. Edible bird's nest extract inhibits influenza virus infection.

    PubMed

    Guo, Chao-Tan; Takahashi, Tadanobu; Bukawa, Wakoto; Takahashi, Noriko; Yagi, Hirokazu; Kato, Koichi; Hidari, Kazuya I-P Jwa; Miyamoto, Daisei; Suzuki, Takashi; Suzuki, Yasuo

    2006-07-01

    Edible bird's nest (EBN) is the nest of the swift that is made from its saliva. Although EBN has been widely used for enhancing immunocompetence, its antiviral efficacy has not been studied in detail. We found that EBN extract could strongly inhibit infection with influenza viruses in a host range-independent manner when it was hydrolyzed with Pancreatin F. Western blotting assay showed that the EBN extract bound to influenza virus. Furthermore, EBN extract could neutralize the infection of MDCK cells with influenza viruses and inhibit hemagglutination of influenza viruses to erythrocytes, but it could not inhibit the activity of influenza virus sialidase. Fluorometric HPLC indicated that the major molecular species of sialic acid in EBN is N-acetylneuraminic acid. The results suggest that EBN is a safe and valid natural source for the prevention of influenza viruses. PMID:16581142

  12. Transmission of Influenza B Viruses in the Guinea Pig

    PubMed Central

    Pica, Natalie; Chou, Yi-Ying; Bouvier, Nicole M.

    2012-01-01

    Epidemic influenza is typically caused by infection with viruses of the A and B types and can result in substantial morbidity and mortality during a given season. Here we demonstrate that influenza B viruses can replicate in the upper respiratory tract of the guinea pig and that viruses of the two main lineages can be transmitted with 100% efficiency between inoculated and naïve animals in both contact and noncontact models. Our results also indicate that, like in the case for influenza A virus, transmission of influenza B viruses is enhanced at colder temperatures, providing an explanation for the seasonality of influenza epidemics in temperate climates. We therefore present, for the first time, a small animal model with which to study the underlying mechanisms of influenza B virus transmission. PMID:22301149

  13. EXISTING ANTIVIRALS ARE EFFECTIVE AGAINST INFLUENZA VIRUSES WITH GENES FROM THE 1918 PANDEMIC VIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 1918 influenza pandemic caused more than 20 million deaths worldwide. Under biosafety level 3Ag containment, a recombinant influenza virus bearing the 1918 influenza virus hemagglutinin (HA) and neuraminidase (NA) was generated. This virus is highly virulent in mice, pointing to the 1918 HA and...

  14. Pathogenesis and pathobiology of avian influenza virus infection in birds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian Influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological features in chickens, AI viruses are categorized as, low (LP) and high pathogenicity (HP). Typically, LPAI (low pathogenicity avian influenza) viruses ...

  15. Global migration of influenza A viruses in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. Novel routes of transmission of influenza viruses in poultry species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to develop better control measures against influenza it’s necessary to understand how the virus transmits in different species. The presence of avian and swine influenza virus genes in the 2009 novel H1N1 pandemic virus (pH1N1) raises the potential for infection in poultry following exposur...

  17. Animal models for influenza virus pathogenesis, transmission, and immunology

    PubMed Central

    Thangavel, Rajagowthamee R.; Bouvier, Nicole M.

    2014-01-01

    In humans, infection with an influenza A or B virus manifests typically as an acute and self-limited upper respiratory tract illness characterized by fever, cough, sore throat, and malaise. However, influenza can present along a broad spectrum of disease, ranging from sub-clinical or even asymptomatic infection to a severe primary viral pneumonia requiring advanced medical supportive care. Disease severity depends upon the virulence of the influenza virus strain and the immune competence and previous influenza exposures of the patient. Animal models are used in influenza research not only to elucidate the viral and host factors that affect influenza disease outcomes in and spread among susceptible hosts, but also to evaluate interventions designed to prevent or reduce influenza morbidity and mortality in man. This review will focus on the three animal models currently used most frequently in influenza virus research -- mice, ferrets, and guinea pigs -- and discuss the advantages and disadvantages of each. PMID:24709389

  18. Cross talk between animal and human influenza viruses.

    PubMed

    Ozawa, Makoto; Kawaoka, Yoshihiro

    2013-01-01

    Although outbreaks of highly pathogenic avian influenza in wild and domestic birds have been posing the threat of a new influenza pandemic for the past decade, the first pandemic of the twenty-first century came from swine viruses. This fact emphasizes the complexity of influenza viral ecology and the difficulty of predicting influenza viral dynamics. Complete control of influenza viruses seems impossible. However, we must minimize the impact of animal and human influenza outbreaks by learning lessons from past experiences and recognizing the current status. Here, we review the most recent influenza virology data in the veterinary field, including aspects of zoonotic agents and recent studies that assess the pandemic potential of H5N1 highly pathogenic avian influenza viruses. PMID:25387011

  19. Live-attenuated influenza A virus vaccines using a B virus backbone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The currently FDA-licensed live attenuated influenza virus vaccine contains a trivalent mixture of types A (H1N1 and H3N2) and B vaccine viruses. The two A virus vaccines have the backbone of a cold-adapted influenza A virus and the B virus vaccine has the six backbone segments derived from a cold-...

  20. The global antigenic diversity of swine influenza A viruses.

    PubMed

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

    2016-01-01

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

  1. Influenza virus vaccine for neglected hosts: horses and dogs.

    PubMed

    Na, Woonsung; Yeom, Minjoo; Yuk, Huijoon; Moon, Hyoungjoon; Kang, Bokyu; Song, Daesub

    2016-07-01

    This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. There have been case reports of genetic reassortment between human and canine influenza viruses, which results in high virulence and the ability of transmission to ferrets. This emphasizes the need for vaccine research on neglected hosts to update knowledge on current strains and to advance technology for controlling influenza outbreaks for public health. PMID:27489801

  2. Influenza virus vaccine for neglected hosts: horses and dogs

    PubMed Central

    2016-01-01

    This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. There have been case reports of genetic reassortment between human and canine influenza viruses, which results in high virulence and the ability of transmission to ferrets. This emphasizes the need for vaccine research on neglected hosts to update knowledge on current strains and to advance technology for controlling influenza outbreaks for public health. PMID:27489801

  3. 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. PMID:26671828

  4. A recombinant influenza virus vaccine expressing the F protein of respiratory syncytial virus

    PubMed Central

    Fonseca, Wendy; Ozawa, Makoto; Hatta, Masato; Orozco, Esther; Martínez, Máximo B; Kawaoka, Yoshihiro

    2014-01-01

    Infections with influenza and respiratory syncytial virus (RSV) rank high among the most common human respiratory diseases worldwide. Previously, we developed a replication-incompetent influenza virus by replacing the coding sequence of the PB2 gene, which encodes one of the viral RNA polymerase subunits, with that of a reporter gene. Here, we generated a PB2-knockout recombinant influenza virus expressing the F protein of RSV (PB2-RSVF virus) and tested its potential as a bivalent vaccine. In mice intranasally immunized with the PB2-RSVF virus, we detected high levels of antibodies against influenza virus, but not RSV. PB2-RSVF virus-immunized mice were protected from a lethal challenge with influenza virus but experienced severe body weight loss when challenged with RSV, indicating that PB2-RSVF vaccination enhanced RSV-associated disease. These results highlight one of the difficulties of developing an effective bivalent vaccine against influenza virus and RSV infections. PMID:24292020

  5. Attenuation of human influenza a viruses

    PubMed Central

    Beare, A. S.; Bynoe, M. L.

    1969-01-01

    The attenuation of two human influenza A viruses has been carried out, using the selection of inhibitor-resistant strains and multiple passages at low temperatures. A virus related to A2/Tokyo/3/67 was obtained in an inhibitor-resistant form. When this was compared with the inhibitor-sensitive strain in a volunteer trial it was relatively non-pathogenic. The second virus, A2/Hongkong/1/68, was subjected to much longer treatment, but nevertheless remained slightly sensitive to serum inhibitor. When given to volunteers it was less pathogenic than before but attenuation was incomplete. A2/Hongkong/1/68 was also modified by passage at low temperatures. Many of these passages are apparently necessary for full attenuation. All attenuated viruses were infective and antigenic. PMID:4900146

  6. Phylogenetic analysis of the haemagglutinin gene of canine distemper virus strains detected from giant panda and raccoon dogs in China

    PubMed Central

    2013-01-01

    Background Canine distemper virus (CDV) infects a variety of carnivores, including wild and domestic Canidae. In this study, we sequenced and phylogenetic analyses of the hemagglutinin (H) genes from eight canine distemper virus (CDV) isolates obtained from seven raccoon dogs (Nyctereutes procyonoides) and a giant panda (Ailuropoda melanoleuca) in China. Results Phylogenetic analysis of the partial hemagglutinin gene sequences showed close clustering for geographic lineages, clearly distinct from vaccine strains and other wild-type foreign CDV strains, all the CDV strains were characterized as Asia-1 genotype and were highly similar to each other (91.5-99.8% nt and 94.4-99.8% aa). The giant panda and raccoon dogs all were 549Y on the HA protein in this study, irrespective of the host species. Conclusions These findings enhance our knowledge of the genetic characteristics of Chinese CDV isolates, and may facilitate the development of effective strategies for monitoring and controlling CDV for wild canids and non-cainds in China. PMID:23566727

  7. Influenza virus infection, ozone exposure, and fibrogenesis.

    PubMed

    Jakab, G J; Bassett, D J

    1990-05-01

    Oxidant exposure following chemically induced lung injury exacerbates the tendency to develop pulmonary fibrosis. Influenza virus pneumonitis causes severe acute lung damage that, upon resolution, is followed by a persistent alveolitis and parenchymal changes characterized by patchy interstitial pneumonia and collagen deposition in the affected areas. To determine whether oxidant exposure exacerbates the virus-induced alveolitis and residual lung damage, mice were infected by aerosol inhalation with influenza A virus and continuously exposed to 0.5 ppm ozone or ambient air. Noninfected control mice were exposed to either ambient air or ozone. On various days during the first month after infection, groups of mice were sacrificed and their lungs assessed for acute injury (lung lavage albumin, total and differential cell counts, wet/dry ratios, and morphometry). At 30, 60, 90, and 120 days after infection, groups of mice were sacrificed for total and differential lavage cell counts, lung hydroxyproline content, and morphometric analysis. Ozone exposure did not alter the proliferation of virus in the lungs as quantitated by infectious virus titers of lung homogenates at 1, 4, 7, 10, and 15 days after virus infection but mitigated the virus-induced acute lung injury by approximately 50%. After Day 30 a shift in the character of the pulmonary lesions was observed in that continuous exposure to ozone potentiated the postinfluenzal alveolitis and structural changes in the lung parenchyma. Additional studies suggest that the mechanism for the enhanced postinfluenzal lung damage may be related to the oxidant impairing the repair process of the acute influenzal lung damage. These data demonstrate that ozone exposure mitigates acute virus-induced lung injury and potentiates residual lung damage. PMID:2339849

  8. Neuraminidase inhibitors for influenza B virus infection: efficacy and resistance

    PubMed Central

    Burnham, Andrew J.; Baranovich, Tatiana; Govorkova, Elena A.

    2013-01-01

    Many aspects of the biology and epidemiology of influenza B viruses are far less studied than for influenza A viruses, and one of these aspects is effectiveness and resistance to the clinically available antiviral drugs, the neuraminidase (NA) inhibitors (NAIs). Acute respiratory infections are one of the leading causes of death in children and adults, and influenza is among the few respiratory infections that can be prevented and treated by vaccination and antiviral treatment. Recent data has suggested that influenza B virus infections are of specific concern to pediatric patients because of the increased risk of severe disease. Treatment of influenza B is a challenging task for the following reasons: NAIs (e.g., oseltamivir and zanamivir) are the only FDA-approved class of antivirals available for treatment;the data suggest that oseltamivir is less effective than zanamivir in pediatric patients;zanamivir is not prescribed to patients younger than 7;influenza B viruses are less susceptible than influenza A viruses to NAIs in vitro;although the level of resistance to NAIs is low, the number of different molecular markers of resistance is higher than for influenza A viruses, and they are not well defined;the relationship between levels of NAI phenotypic resistance and known molecular markers, frequency of emergence, transmissibility, and fitness of NAI-resistant variants are not well established. This review presents current knowledge of the effectiveness of NAIs for influenza B virus and antiviral resistance in clinical, surveillance, and experimental studies. PMID:24013000

  9. Characterization of influenza virus among influenza like illness cases in Mumbai, India.

    PubMed

    Roy, Soumen; Dahake, Ritwik; Patil, Deepak; Tawde, Shweta; Mukherjee, Sandeepan; Athlekar, Shrikant; Chowdhary, Abhay; Deshmukh, Ranjana

    2014-01-01

    The present study was carried out to monitor influenza viruses by identifying the virus and studying the seasonal variation during 2007-2009 in Mumbai. A total of 193 clinical respiratory samples (nasal and throat swab) were collected from patients having influenza like illness in Mumbai region. One-step real-time reverse-transcriptase PCR (rRTPCR) was used to detect Influenza type A (H1 and H3) and Influenza type B virus. Isolation of the virus was carried out using in vitro system which was further confirmed and typed by hemagglutination assay and hemagglutination inhibition assay. Out of 193 samples 24 (12.4 3%) samples tested positive for influenza virus, of which 13 (6.73 %) were influenza type A virus and 10 (5.18 %) were influenza type B virus, while 1 sample (0.51 %) was positive for both. By culture methods, 3 (1.55 %) viral isolates were obtained. All the three isolates were found to be Influenza type B/Malaysia (Victoria lineage) by Hemagglutination Inhibition Assay. The data generated from the present study reveals that both Influenza type A and B are prevalent in Mumbai with considerable activity. The peak activity was observed during monsoon season. PMID:25674606

  10. Pathogenicity and transmissibility of reassortant H9 influenza viruses with genes from pandemic H1N1 virus

    PubMed Central

    Qiao, Chuanling; Liu, Qinfang; Bawa, Bhupinder; Shen, Huigang; Qi, Wenbao; Chen, Ying; Mok, Chris Ka Pun; García-Sastre, Adolfo; Richt, Jürgen A.

    2012-01-01

    Both H9N2 avian influenza and 2009 pandemic H1N1 viruses (pH1N1) are able to infect humans and swine, which has raised concerns that novel reassortant H9 viruses with pH1N1 genes might be generated in these hosts by reassortment. Although previous studies have demonstrated that reassortant H9 viruses with pH1N1 genes show increased virulence in mice and transmissibility in ferrets, the virulence and transmissibility of reassortant H9 viruses in natural hosts such as chickens and swine remain unknown. This study generated two reassortant H9 viruses (H9N2/CA09 and H9N1/CA09) in the background of the pH1N1 A/California/04/2009 (CA09) virus by replacing either both the haemagglutinin (HA) and neuraminidase (NA) genes or only the HA gene with the respective genes from the A/quail/Hong Kong/G1/1997 (H9N2) virus and evaluated their replication, pathogenicity and transmission in chickens and pigs compared with the parental viruses. Chickens that were infected with the parental H9N2 and reassortant H9 viruses seroconverted. The parental H9N2 and reassortant H9N2/CA09 viruses were transmitted to sentinel chickens, but H9N1/CA09 virus was not. The parental H9N2 replicated poorly and was not transmitted in pigs, whereas both H9N2/CA09 and H9N1/CA09 viruses replicated and were transmitted efficiently in pigs, similar to the pH1N1 virus. These results demonstrated that reassortant H9 viruses with pH1N1 genes show enhanced replication and transmissibility in pigs compared with the parental H9N2 virus, indicating that they may pose a threat for humans if such reassortants arise in swine. PMID:22875253

  11. H7N9 influenza A virus in turkeys in Minnesota

    PubMed Central

    Lebarbenchon, Camille; Pedersen, Janice C.; Sreevatsan, Srinand; Ramey, Andrew M.; Dugan, Vivien G.; Halpin, Rebecca A.; Ferro, Pamela J.; Lupiani, Blanca; Enomoto, Shinichiro; Poulson, Rebecca L.; Smeltzer, Martin; Cardona, Carol J.; Tompkins, S. Mark; Wentworth, David E.; Stallknecht, David E.

    2015-01-01

    Introductions of H7 influenza A virus (IAV) from wild birds into poultry have been documented worldwide, resulting in varying degrees of morbidity and mortality. H7 IAV infection in domestic poultry has served as a source of human infection and disease. We report the detection of H7N9 subtype IAVs in Minnesota (MN) turkey farms during 2009 and 2011. The full genome was sequenced from eight isolates as well as the haemagglutinin (HA) and neuraminidase (NA) gene segments of H7 and N9 virus subtypes for 108 isolates from North American wild birds between 1986 and 2012. Through maximum-likelihood and coalescent phylogenetic analyses, we identified the recent H7 and N9 IAV ancestors of the turkey-origin H7N9 IAVs, estimated the time and geographical origin of the ancestral viruses, and determined the relatedness between the 2009 and 2011 turkey-origin H7N9 IAVs. Analyses supported that the 2009 and 2011 viruses were distantly related genetically, suggesting that the two outbreaks arose from independent introduction events from wild birds. Our findings further supported that the 2011 MN turkey-origin H7N9 virus was closely related to H7N9 IAVs isolated in poultry in Nebraska during the same year. Although the precise origin of the wild-bird donor of the turkey-origin H7N9 IAVs could not be determined, our findings suggested that, for both the NA and HA gene segments, the MN turkey-origin H7N9 viruses were related to viruses circulating in wild birds between 2006 and 2011 in the Mississippi Flyway. PMID:25351723

  12. 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

  13. Quantification of Influenza Virus RNA in Aerosols in Patient Rooms

    PubMed Central

    Leung, Nancy H. L.; Zhou, Jie; Chu, Daniel K. W.; Yu, Han; Lindsley, William G.; Beezhold, Donald H.; Yen, Hui-Ling; Li, Yuguo; Seto, Wing-Hong; Peiris, Joseph S. M.; Cowling, Benjamin J.

    2016-01-01

    Background The potential for human influenza viruses to spread through fine particle aerosols remains controversial. The objective of our study was to determine whether influenza viruses could be detected in fine particles in hospital rooms. Methods and Findings We sampled the air in 2-bed patient isolation rooms for four hours, placing cyclone samplers at heights of 1.5m and 1.0m. We collected ten air samples each in the presence of at least one patient with confirmed influenza A virus infection, and tested the samples by reverse transcription polymerase chain reaction. We recovered influenza A virus RNA from 5/10 collections (50%); 4/5 were from particles>4 μm, 1/5 from 1–4 μm, and none in particles<1 μm. Conclusions Detection of influenza virus RNA in aerosols at low concentrations in patient rooms suggests that healthcare workers and visitors might have frequent exposure to airborne influenza virus in proximity to infected patients. A limitation of our study was the small sample size. Further studies should be done to quantify the concentration of viable influenza virus in healthcare settings, and factors affecting the detection of influenza viruses in fine particles in the air. PMID:26849130

  14. Saikosaponin A inhibits influenza A virus replication and lung immunopathology.

    PubMed

    Chen, Jianxin; Duan, Mubing; Zhao, Yaqin; Ling, Fangfang; Xiao, Kun; Li, Qian; Li, Bin; Lu, Chunni; Qi, Wenbao; Zeng, Zhenling; Liao, Ming; Liu, Yahong; Chen, Weisan

    2015-12-15

    Fatal influenza outcomes result from a combination of rapid virus replication and collateral lung tissue damage caused by exaggerated pro-inflammatory host immune cell responses. There are few therapeutic agents that target both biological processes for the attenuation of influenza-induced lung pathology. We show that Saikosaponin A, a bioactive triterpene saponin with previouslyestablished anti-inflammatory effects, demonstrates both in vitro and in vivo anti-viral activity against influenza A virus infections. Saikosaponin A attenuated the replication of three different influenza A virus strains, including a highly pathogenic H5N1 strain, in human alveolar epithelial A549 cells. This anti-viral activity occurred through both downregulation of NF-κB signaling and caspase 3-dependent virus ribonucleoprotein nuclear export as demonstrated by NF-κB subunit p65 and influenza virus nucleoprotein nuclear translocation studies in influenza virus infected A549 cells. Critically, Saikosaponin A also attenuated viral replication, aberrant pro-inflammatory cytokine production and lung histopathology in the widely established H1N1 PR8 model of influenza A virus lethality in C57BL/6 mice. Flow cytometry studies of mouse bronchoalveolar lavage cells revealed that SSa exerted immunomodulatory effects through a selective attenuation of lung neutrophil and monocyte recruitment during the early peak of the innate immune response to PR8 infection. Altogether, our results indicate that Saikosaponin A possesses novel therapeutic potential for the treatment of pathological influenza virus infections. PMID:26637810

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine influenza presents a substantial disease burden for pig populations worldwide and poses a potential pandemic threat to humans. There is considerable diversity in both H1 and H3 influenza viruses circulating in swine due to the frequent introductions of viruses from humans and birds coupled wit...

  16. Experimental Infection of Pigs with the 1918 Pandemic Influenza Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine influenza was first recognized as a disease during the 1918 "Spanish flu" pandemic suggesting the Spanish flu virus caused swine influenza. The objective of this study was to determine the susceptibility of swine to the Spanish flu virus. A plasmid-derived 1918 pandemic H1N1 (1918/rec) influe...

  17. Sequencing of avian influenza virus genomes following random amplification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian Influenza (AI) is a significant disease of birds and a threat to humans. Recently, as a result of the emergence of Asian H5N1 viruses capable of zoonotic spread, wild and domestic bird surveillance for Avian Influenza viruses (AIV) has increased worldwide, requiring the development of fast a...

  18. Saikosaponin A inhibits influenza A virus replication and lung immunopathology

    PubMed Central

    Zhao, Yaqin; Ling, Fangfang; Xiao, Kun; Li, Qian; Li, Bin; Lu, Chunni; Qi, Wenbao; Zeng, Zhenling; Liao, Ming; Liu, Yahong; Chen, Weisan

    2015-01-01

    Fatal influenza outcomes result from a combination of rapid virus replication and collateral lung tissue damage caused by exaggerated pro-inflammatory host immune cell responses. There are few therapeutic agents that target both biological processes for the attenuation of influenza-induced lung pathology. We show that Saikosaponin A, a bioactive triterpene saponin with previouslyestablished anti-inflammatory effects, demonstrates both in vitro and in vivo anti-viral activity against influenza A virus infections. Saikosaponin A attenuated the replication of three different influenza A virus strains, including a highly pathogenic H5N1 strain, in human alveolar epithelial A549 cells. This anti-viral activity occurred through both downregulation of NF-κB signaling and caspase 3-dependent virus ribonucleoprotein nuclear export as demonstrated by NF-κB subunit p65 and influenza virus nucleoprotein nuclear translocation studies in influenza virus infected A549 cells. Critically, Saikosaponin A also attenuated viral replication, aberrant pro-inflammatory cytokine production and lung histopathology in the widely established H1N1 PR8 model of influenza A virus lethality in C57BL/6 mice. Flow cytometry studies of mouse bronchoalveolar lavage cells revealed that SSa exerted immunomodulatory effects through a selective attenuation of lung neutrophil and monocyte recruitment during the early peak of the innate immune response to PR8 infection. Altogether, our results indicate that Saikosaponin A possesses novel therapeutic potential for the treatment of pathological influenza virus infections. PMID:26637810

  19. Experimental vaccinations for avian influenza virus including DIVA approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) is a viral disease of poultry that remains an economic threat to commercial poultry throughout the world by negatively impacting animal health and trade. Strategies to control avian influenza (AI) virus are developed to prevent, manage or eradicate the virus from the country, re...

  20. Seasonal trivalent inactivated influenza vaccine protects against 1918 Spanish influenza virus in ferrets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influenza H1N1 pandemic of 1918 was one of the worst medical disasters in human history. Recent studies have demonstrated that the hemagglutinin (HA) protein of the 1918 virus and 2009 H1N1 pandemic virus, the latter now a component of the seasonal trivalent inactivated influenza vaccine (TIV),...

  1. Ecology of avian influenza virus in birds.

    PubMed

    Causey, Douglas; Edwards, Scott V

    2008-02-15

    Avian influenza A virus (an orthomyxovirus) is a zoonotic pathogen with a natural reservoir entirely in birds. The influenza virus genome is an 8-segment single-stranded RNA with high potential for in situ recombination. Two segments code for the hemagglutinin (H) and neuraminidase (N) antigens used for host-cell entry. At present, 16 H and 9 N subtypes are known, for a total of 144 possible different influenza subtypes, each with potentially different host susceptibility. With >10,000 species of birds found in nearly every terrestrial and aquatic habitat, there are few places on earth where birds cannot be found. The avian immune system differs from that of humans in several important features, including asynchronous B and T lymphocyte systems and a polymorphic multigene immune complex, but little is known about the immunogenetics of pathogenic response. Postbreeding dispersal and migration and a naturally high degree of environmental vagility mean that wild birds have the potential to be vectors that transmit highly pathogenic variants great distances from the original sources of infection. PMID:18269325

  2. 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

  3. Evaluation of Alere i Influenza A&B for rapid detection of influenza viruses A and B.

    PubMed

    Nie, Shuping; Roth, Richard B; Stiles, Jeffrey; Mikhlina, Albina; Lu, Xuedong; Tang, Yi-Wei; Babady, N Esther

    2014-09-01

    Rapid and accurate diagnosis of influenza is important for infection control, as well as for patient management. Alere i Influenza A&B is an isothermal nucleic acid amplification-based integrated system for detection and differentiation of influenza virus A and influenza virus B. The performance of the Alere i Influenza A&B was screened using frozen nasopharyngeal-swab specimens collected in viral transport medium (VTM) that were originally tested fresh with the FilmArray Respiratory Panel (RP) assay during the 2012-2013 influenza outbreak. In total, 360 VTM specimens were selected for Alere i Influenza A&B testing: 40 influenza virus A H1N1-2009 (influenza virus A-1), 40 influenza virus A H3N2 (influenza virus A-3), 37 influenza virus A "equivocal" or "no subtype detected" (influenza virus A-u), 41 influenza virus B, and 202 influenza virus-negative specimens, as initially determined by the FilmArray RP assay. The Alere assay showed sensitivities of 87.2%, 92.5%, 25.0%, and 97.4% for influenza virus A-1, influenza virus A-3, influenza virus A-u, and influenza virus B, respectively, after discordant resolution by Prodesse ProFLU+ PCR. The specificities were 100% for both influenza virus A and influenza virus B. In general, the Alere i Influenza A&B provided good sensitivity, although the assay did show poorer sensitivity with samples determined to have low influenza virus A titers by Prodesse ProFlu+ PCR (a mean real-time PCR threshold cycle [CT] value of 31.9 ± 2.0), which included the majority of the samples called influenza virus A "equivocal" or "no subtype detected" by a single BioFire FilmArray RP test. The integrated, rapid, and simple characteristics of the Alere i Influenza A&B assay make it a potential candidate for point-of-care testing, with a test turnaround time of less than 15 min. PMID:24989611

  4. The contrasting phylodynamics of human influenza B viruses.

    PubMed

    Vijaykrishna, Dhanasekaran; Holmes, Edward C; Joseph, Udayan; Fourment, Mathieu; Su, Yvonne C F; Halpin, Rebecca; Lee, Raphael T C; Deng, Yi-Mo; Gunalan, Vithiagaran; Lin, Xudong; Stockwell, Timothy B; Fedorova, Nadia B; Zhou, Bin; Spirason, Natalie; Kühnert, Denise; Bošková, Veronika; Stadler, Tanja; Costa, Anna-Maria; Dwyer, Dominic E; Huang, Q Sue; Jennings, Lance C; Rawlinson, William; Sullivan, Sheena G; Hurt, Aeron C; Maurer-Stroh, Sebastian; Wentworth, David E; Smith, Gavin J D; Barr, Ian G

    2015-01-01

    A complex interplay of viral, host, and ecological factors shapes the spatio-temporal incidence and evolution of human influenza viruses. Although considerable attention has been paid to influenza A viruses, a lack of equivalent data means that an integrated evolutionary and epidemiological framework has until now not been available for influenza B viruses, despite their significant disease burden. Through the analysis of over 900 full genomes from an epidemiological collection of more than 26,000 strains from Australia and New Zealand, we reveal fundamental differences in the phylodynamics of the two co-circulating lineages of influenza B virus (Victoria and Yamagata), showing that their individual dynamics are determined by a complex relationship between virus transmission, age of infection, and receptor binding preference. In sum, this work identifies new factors that are important determinants of influenza B evolution and epidemiology. PMID:25594904

  5. The contrasting phylodynamics of human influenza B viruses

    PubMed Central

    Vijaykrishna, Dhanasekaran; Holmes, Edward C; Joseph, Udayan; Fourment, Mathieu; Su, Yvonne CF; Halpin, Rebecca; Lee, Raphael TC; Deng, Yi-Mo; Gunalan, Vithiagaran; Lin, Xudong; Stockwell, Timothy B; Fedorova, Nadia B; Zhou, Bin; Spirason, Natalie; Kühnert, Denise; Bošková, Veronika; Stadler, Tanja; Costa, Anna-Maria; Dwyer, Dominic E; Huang, Q Sue; Jennings, Lance C; Rawlinson, William; Sullivan, Sheena G; Hurt, Aeron C; Maurer-Stroh, Sebastian; Wentworth, David E; Smith, Gavin JD; Barr, Ian G

    2015-01-01

    A complex interplay of viral, host, and ecological factors shapes the spatio-temporal incidence and evolution of human influenza viruses. Although considerable attention has been paid to influenza A viruses, a lack of equivalent data means that an integrated evolutionary and epidemiological framework has until now not been available for influenza B viruses, despite their significant disease burden. Through the analysis of over 900 full genomes from an epidemiological collection of more than 26,000 strains from Australia and New Zealand, we reveal fundamental differences in the phylodynamics of the two co-circulating lineages of influenza B virus (Victoria and Yamagata), showing that their individual dynamics are determined by a complex relationship between virus transmission, age of infection, and receptor binding preference. In sum, this work identifies new factors that are important determinants of influenza B evolution and epidemiology. DOI: http://dx.doi.org/10.7554/eLife.05055.001 PMID:25594904

  6. Research update on avian influenza viruses and H1N1 influenza virus in poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) remains an economic threat to commercial poultry throughout the world by negatively impacting animal health and trade. Southeast Poultry Research Laboratory conducts research on many areas related to AI including pathogenesis and transmission studies, use of vaccination, virus ...

  7. 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

  8. The Mutational Robustness of Influenza A Virus.

    PubMed

    Visher, Elisa; Whitefield, Shawn E; McCrone, John T; Fitzsimmons, William; Lauring, Adam S

    2016-08-01

    A virus' mutational robustness is described in terms of the strength and distribution of the mutational fitness effects, or MFE. The distribution of MFE is central to many questions in evolutionary theory and is a key parameter in models of molecular evolution. Here we define the mutational fitness effects in influenza A virus by generating 128 viruses, each with a single nucleotide mutation. In contrast to mutational scanning approaches, this strategy allowed us to unambiguously assign fitness values to individual mutations. The presence of each desired mutation and the absence of additional mutations were verified by next generation sequencing of each stock. A mutation was considered lethal only after we failed to rescue virus in three independent transfections. We measured the fitness of each viable mutant relative to the wild type by quantitative RT-PCR following direct competition on A549 cells. We found that 31.6% of the mutations in the genome-wide dataset were lethal and that the lethal fraction did not differ appreciably between the HA- and NA-encoding segments and the rest of the genome. Of the viable mutants, the fitness mean and standard deviation were 0.80 and 0.22 in the genome-wide dataset and best modeled as a beta distribution. The fitness impact of mutation was marginally lower in the segments coding for HA and NA (0.88 ± 0.16) than in the other 6 segments (0.78 ± 0.24), and their respective beta distributions had slightly different shape parameters. The results for influenza A virus are remarkably similar to our own analysis of CirSeq-derived fitness values from poliovirus and previously published data from other small, single stranded DNA and RNA viruses. These data suggest that genome size, and not nucleic acid type or mode of replication, is the main determinant of viral mutational fitness effects. PMID:27571422

  9. Inhibitors of influenza viruses replication: a patent evaluation (WO2013019828).

    PubMed

    Xie, Yuanchao; Song, Weiguo; Xiao, Weidong; Gu, Changjuan; Xu, Wenfang

    2013-11-01

    A series of compounds incorporating two aromatic heterocycles were prepared as inhibitors of influenza virus replication in the patent. Some of them presented potent activity against influenza virus in Madin-Darby canine kidney (MDCK) cells and in influenza therapeutic mouse model. These compounds in the patent were also defined to be pharmaceutically acceptable salts and pharmaceutical compositions that were claimed to be useful for treating influenza. In view of the threat of influenza pandemic, it is necessary to discover new anti-influenza drugs. Although there is a lack of essential biological data and the molecular mechanisms are not clear, these compounds with potent antiviral activity stand for a new type of anti-influenza agents and deserve further studies. PMID:23967861

  10. Sialic acid tissue distribution and influenza virus tropism

    PubMed Central

    Kumlin, Urban; Olofsson, Sigvard; Dimock, Ken; Arnberg, Niklas

    2008-01-01

    Abstract  Avian influenza A viruses exhibit a strong preference for using α2,3‐linked sialic acid as a receptor. Until recently, the presumed lack of this receptor in human airways was believed to constitute an efficient barrier to avian influenza A virus infection of humans. Recent zoonotic outbreaks of avian influenza A virus have triggered researchers to analyse tissue distribution of sialic acid in further detail. Here, we review and extend the current knowledge about sialic acid distribution in human tissues, and discuss viruses with ocular tropism and their preference for α2,3‐linked sialic acid. PMID:19453419

  11. Modeling Influenza Virus Infection: A Roadmap for Influenza Research

    PubMed Central

    Boianelli, Alessandro; Nguyen, Van Kinh; Ebensen, Thomas; Schulze, Kai; Wilk, Esther; Sharma, Niharika; Stegemann-Koniszewski, Sabine; Bruder, Dunja; Toapanta, Franklin R.; Guzmán, Carlos A.; Meyer-Hermann, Michael; Hernandez-Vargas, Esteban A.

    2015-01-01

    Influenza A virus (IAV) infection represents a global threat causing seasonal outbreaks and pandemics. Additionally, secondary bacterial infections, caused mainly by Streptococcus pneumoniae, are one of the main complications and responsible for the enhanced morbidity and mortality associated with IAV infections. In spite of the significant advances in our knowledge of IAV infections, holistic comprehension of the interplay between IAV and the host immune response (IR) remains largely fragmented. During the last decade, mathematical modeling has been instrumental to explain and quantify IAV dynamics. In this paper, we review not only the state of the art of mathematical models of IAV infection but also the methodologies exploited for parameter estimation. We focus on the adaptive IR control of IAV infection and the possible mechanisms that could promote a secondary bacterial coinfection. To exemplify IAV dynamics and identifiability issues, a mathematical model to explain the interactions between adaptive IR and IAV infection is considered. Furthermore, in this paper we propose a roadmap for future influenza research. The development of a mathematical modeling framework with a secondary bacterial coinfection, immunosenescence, host genetic factors and responsiveness to vaccination will be pivotal to advance IAV infection understanding and treatment optimization. PMID:26473911

  12. Development of Framework for Assessing Influenza Virus Pandemic Risk

    PubMed Central

    Burke, Stephen A.; Cox, Nancy J.

    2015-01-01

    Although predicting which influenza virus subtype will cause the next pandemic is not yet possible, public health authorities must continually assess the pandemic risk associated with animal influenza viruses, particularly those that have caused infections in humans, and determine what resources should be dedicated to mitigating that risk. To accomplish this goal, a risk assessment framework was created in collaboration with an international group of influenza experts. Compared with the previously used approach, this framework, named the Influenza Risk Assessment Tool, provides a systematic and transparent approach for assessing and comparing threats posed primarily by avian and swine influenza viruses. This tool will be useful to the international influenza community and will remain flexible and responsive to changing information. PMID:26196098

  13. Current Approaches for Diagnosis of Influenza Virus Infections in Humans.

    PubMed

    Vemula, Sai Vikram; Zhao, Jiangqin; Liu, Jikun; Wang, Xue; Biswas, Santanu; Hewlett, Indira

    2016-04-01

    Despite significant advancement in vaccine and virus research, influenza continues to be a major public health concern. Each year in the United States of America, influenza viruses are responsible for seasonal epidemics resulting in over 200,000 hospitalizations and 30,000-50,000 deaths. Accurate and early diagnosis of influenza viral infections are critical for rapid initiation of antiviral therapy to reduce influenza related morbidity and mortality both during seasonal epidemics and pandemics. Several different approaches are currently available for diagnosis of influenza infections in humans. These include viral isolation in cell culture, immunofluorescence assays, nucleic acid amplification tests, immunochromatography-based rapid diagnostic tests, etc. Newer diagnostic approaches are being developed to overcome the limitations associated with some of the conventional detection methods. This review discusses diagnostic approaches currently available for detection of influenza viruses in humans. PMID:27077877

  14. Current Approaches for Diagnosis of Influenza Virus Infections in Humans

    PubMed Central

    Vemula, Sai Vikram; Zhao, Jiangqin; Liu, Jikun; Wang, Xue; Biswas, Santanu; Hewlett, Indira

    2016-01-01

    Despite significant advancement in vaccine and virus research, influenza continues to be a major public health concern. Each year in the United States of America, influenza viruses are responsible for seasonal epidemics resulting in over 200,000 hospitalizations and 30,000–50,000 deaths. Accurate and early diagnosis of influenza viral infections are critical for rapid initiation of antiviral therapy to reduce influenza related morbidity and mortality both during seasonal epidemics and pandemics. Several different approaches are currently available for diagnosis of influenza infections in humans. These include viral isolation in cell culture, immunofluorescence assays, nucleic acid amplification tests, immunochromatography-based rapid diagnostic tests, etc. Newer diagnostic approaches are being developed to overcome the limitations associated with some of the conventional detection methods. This review discusses diagnostic approaches currently available for detection of influenza viruses in humans. PMID:27077877

  15. Development of a surveillance scheme for equine influenza in the UK and characterisation of viruses isolated in Europe, Dubai and the USA from 2010-2012.

    PubMed

    Woodward, Alana L; Rash, Adam S; Blinman, Donna; Bowman, Samantha; Chambers, Thomas M; Daly, Janet M; Damiani, Armando; Joseph, Sunitha; Lewis, Nicola; McCauley, John W; Medcalf, Liz; Mumford, Jenny; Newton, J Richard; Tiwari, Ashish; Bryant, Neil A; Elton, Debra M

    2014-03-14

    Equine influenza viruses are a major cause of respiratory disease in horses worldwide and undergo antigenic drift. Several outbreaks of equine influenza occurred worldwide during 2010-2012, including in vaccinated animals, highlighting the importance of surveillance and virus characterisation. Virus isolates were characterised from more than 20 outbreaks over a 3-year period, including strains from the UK, Dubai, Germany and the USA. The haemagglutinin-1 (HA1) sequence of all isolates was determined and compared with OIE-recommended vaccine strains. Viruses from Florida clades 1 and 2 showed continued divergence from each other compared with 2009 isolates. The antigenic inter-relationships among viruses were determined using a haemagglutination-inhibition (HI) assay with ferret antisera and visualised using antigenic cartography. All European isolates belonged to Florida clade 2, all those from the USA belonged to Florida clade 1. Two subpopulations of clade 2 viruses were isolated, with either substitution A144V or I179V. Isolates from Dubai, obtained from horses shipped from Uruguay, belonged to Florida clade 1 and were similar to viruses isolated in the USA the previous year. The neuraminidase (NA) sequence of representative strains from 2007 and 2009 to 2012 was also determined and compared with that of earlier isolates dating back to 1963. Multiple changes were observed at the amino acid level and clear distinctions could be made between viruses belonging to Florida clade 1 and clade 2. PMID:24480583

  16. Pathogenesis and transmission of the novel swine-origin influenza virus A/H1N1 after experimental infection of pigs.

    PubMed

    Lange, Elke; Kalthoff, Donata; Blohm, Ulrike; Teifke, Jens P; Breithaupt, Angele; Maresch, Christina; Starick, Elke; Fereidouni, Sasan; Hoffmann, Bernd; Mettenleiter, Thomas C; Beer, Martin; Vahlenkamp, Thomas W

    2009-09-01

    Influenza virus A/H1N1, which is currently causing a pandemic, contains gene segments with ancestors in the North American and Eurasian swine lineages. To get insights into virus replication dynamics, clinical symptoms and virus transmission in pigs, we infected animals intranasally with influenza virus A/Regensburg/D6/09/H1N1. Virus excretion in the inoculated pigs was detected in nasal swabs from 1 day post-infection (p.i.) onwards and the pigs developed generally mild symptoms, including fever, sneezing, nasal discharge and diarrhoea. Contact pigs became infected, shed virus and developed clinical symptoms similar to those in the inoculated animals. Plasma samples of all animals remained negative for virus RNA. Nucleoprotein- and haemagglutinin H1-specific antibodies could be detected by ELISA 7 days p.i. CD4(+) T cells became activated immediately after infection and both CD4(+) and CD8(+) T-cell populations expanded from 3 to 7 days p.i., coinciding with clinical signs. Contact chickens remained uninfected, as judged by the absence of virus excretion, clinical signs and seroconversion. PMID:19592456

  17. Variability of tropism and replicative capacity of two naturally occurring influenza A H9N2 viruses in cell cultures from different tissues.

    PubMed

    Tombari, Wafa; ElBehi, Imen; Amouna, Faten; Ghram, Abdeljelil

    2016-01-01

    Studies carried out on cell permissivity are of great interest to understand virus replication and pathogenicity. We described the results of a comparative analysis of replication efficiency of two naturally occurring influenza A H9N2 variants isolated from poultry and wild birds, differing by only two substitutions Q226L and T384N, in the receptor-binding site of haemagglutinin and the 380 loop region of NA proteins, respectively. Considering the overall growth of both viruses, lung cultures ensured the most efficient growth of TUN12L226N384 strain with titres up to 10(9) TCID50/ml whereas small intestine culture was highly susceptible to the TUN51Q226T384 virus reaching a titre of 10(6) TCID50/ml. The lowest replication was shown in liver cells. The addition of trypsin was essential for the replication of either virus in primary fibroblasts, but it had a marginal positive effect on virus replication in the four other culture types with maximum titres of 10(8) TCID50/ml. This means that in chicken, the proteolytic activation of the H9N2 viruses with the cleavage motif RSSR may be mediated by other endoproteases than trypsin. Further investigations should concentrate on the production of the appropriate set of viruses by a reverse genetics approach and the examination of cellular protease expression in chicken tissues. This would lead to a more complete understanding of the tropism of low-pathogenic Influenza A viruses. PMID:26813086

  18. Influenza virus pyrogenicity: central role of structural orientation of virion components and involvement of viral lipid and glycoproteins.

    PubMed

    Pickering, J M; Smith, H; Sweet, C

    1992-06-01

    Ultraviolet light-inactivated, non-infectious influenza virus is pyrogenic; virion components are probably responsible for this pyrogenicity. To try to identify the pyrogenic component, influenza virions were disrupted with either bromelain or sodium deoxycholate (DOC). Treatment of infectious virions with bromelain, under conditions that removed the surface glycoproteins (spikes), destroyed their pyrogenicity. The supernatant, containing non-aggregated and modified glycoproteins, was also non-pyrogenic. Disruption of virions with DOC considerably reduced pyrogenicity; however, some was retained by the sub-viral cores. Viral nucleoprotein and matrix protein, purified from the supernatant, were non-pyrogenic. Aggregated stellate clusters of surface glycoproteins separated on sucrose gradients were pyrogenic in half of numerous tests performed with different batches of material. Treatment of virus with ether resulted in complete loss of pyrogenicity. Liposomes made from extracted viral lipid were non-pyrogenic. In contrast, virosomes made from the viral lipid and the aggregated stellate clusters of surface glycoproteins were pyrogenic. Hence, optimum pyrogenicity depends upon the integrity of the virus particle, but haemagglutinin and/or neuraminidase appear essential, and lipid may be involved. PMID:1607857

  19. Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus

    USGS Publications Warehouse

    Hall, Jeffrey S.; Krauss, Scott; Franson, J. Christian; TeSlaa, Joshua L.; Nashold, Sean W.; Stallknecht, David E.; Webby, Richard J.; Webster, Robert G.

    2013-01-01

    Background: Low pathogenic avian influenza viruses (LPAIV) have been reported in shorebirds, especially at Delaware Bay, USA, during spring migration. However, data on patterns of virus excretion, minimal infectious doses, and clinical outcome are lacking. The ruddy turnstone (Arenaria interpres) is the shorebird species with the highest prevalence of influenza virus at Delaware Bay. Objectives: The primary objective of this study was to experimentally assess the patterns of influenza virus excretion, minimal infectious doses, and clinical outcome in ruddy turnstones. Methods: We experimentally challenged ruddy turnstones using a common LPAIV shorebird isolate, an LPAIV waterfowl isolate, or a highly pathogenic H5N1 avian influenza virus. Cloacal and oral swabs and sera were analyzed from each bird. Results: Most ruddy turnstones had pre-existing antibodies to avian influenza virus, and many were infected at the time of capture. The infectious doses for each challenge virus were similar (103·6–104·16 EID50), regardless of exposure history. All infected birds excreted similar amounts of virus and showed no clinical signs of disease or mortality. Influenza A-specific antibodies remained detectable for at least 2 months after inoculation. Conclusions: These results provide a reference for interpretation of surveillance data, modeling, and predicting the risks of avian influenza transmission and movement in these important hosts.

  20. Influenza Virus Aerosols in the Air and Their Infectiousness

    PubMed Central

    2014-01-01

    Influenza is one of the most contagious and rapidly spreading infectious diseases and an important global cause of hospital admissions and mortality. There are some amounts of the virus in the air constantly. These amounts is generally not enough to cause disease in people, due to infection prevention by healthy immune systems. However, at a higher concentration of the airborne virus, the risk of human infection increases dramatically. Early detection of the threshold virus concentration is essential for prevention of the spread of influenza infection. This review discusses different approaches for measuring the amount of influenza A virus particles in the air and assessing their infectiousness. Here we also discuss the data describing the relationship between the influenza virus subtypes and virus air transmission, and distribution of viral particles in aerosol drops of different sizes. PMID:25197278

  1. Keeping the memory of influenza viruses.

    PubMed

    Combadière, B; Sibéril, S; Duffy, D

    2010-04-01

    Protection against pathogens is mediated by both humoral responses (neutralizing antibodies) and cellular immunity, both CD4+ and CD8+ cells. In the case of influenza viruses, circulating strains contain both variable and conserved T and B cell epitopes that are challenged after vaccination and/or infection. During infection, the role of T cells is to prevent viral dissemination in the organism by killing the infected cells and helping B cell antibody production to neutralize the virus. The threat of influenza virus increases the preparedness of protective immunity to pandemic and seasonal infection by vaccination. Several questions remain that need to be further addressed for the future development of innovative and rapidly efficient vaccines strategies. Firstly, what are the correlates of long-term protection (antibodies and/or T cells) against variant strains of influenza? How does the individual factors (age, natural immunity, vaccination and/or infection history) influence the generation and maintenance of memory cells? What are the factors allowing the maintenance of immune memory (regular contact with the pathogen or re-vaccination)? Secondly, what is the nature and quality (function / phenotype / location) of memory B and T cells? Finally, is it necessary to induce and maintain immunological memory against conserved proteins and/or to re-vaccinate against viral variants? What would be the consequences of repeated vaccination? These questions remain a subject of debate that will be further discussed. Since immunological memory is the cornerstone of vaccination, it is essential that we have a better understanding of its generation and maintenance over time as well as its contribution to recall responses during pandemics or after vaccination. PMID:20303671

  2. Influenza virus antigenicity and broadly neutralizing epitopes

    PubMed Central

    Air, Gillian M.

    2015-01-01

    A vaccine formulation that would be effective against all strains of influenza virus has long been a goal of vaccine developers, but antibodies after infection or vaccination were seen to be strain specific and there was little evidence of cross-reactive antibodies that neutralized across subtypes. Recently a number of broadly neutralizing monoclonal antibodies have been characterized. This review describes the different classes of broadly neutralizing antibodies and discusses the potential of their therapeutic use or for design of immunogens that induce a high proportion of broadly neutralizing antibodies. PMID:25846699

  3. The Mutational Robustness of Influenza A Virus

    PubMed Central

    McCrone, John T.; Lauring, Adam S.

    2016-01-01

    A virus’ mutational robustness is described in terms of the strength and distribution of the mutational fitness effects, or MFE. The distribution of MFE is central to many questions in evolutionary theory and is a key parameter in models of molecular evolution. Here we define the mutational fitness effects in influenza A virus by generating 128 viruses, each with a single nucleotide mutation. In contrast to mutational scanning approaches, this strategy allowed us to unambiguously assign fitness values to individual mutations. The presence of each desired mutation and the absence of additional mutations were verified by next generation sequencing of each stock. A mutation was considered lethal only after we failed to rescue virus in three independent transfections. We measured the fitness of each viable mutant relative to the wild type by quantitative RT-PCR following direct competition on A549 cells. We found that 31.6% of the mutations in the genome-wide dataset were lethal and that the lethal fraction did not differ appreciably between the HA- and NA-encoding segments and the rest of the genome. Of the viable mutants, the fitness mean and standard deviation were 0.80 and 0.22 in the genome-wide dataset and best modeled as a beta distribution. The fitness impact of mutation was marginally lower in the segments coding for HA and NA (0.88 ± 0.16) than in the other 6 segments (0.78 ± 0.24), and their respective beta distributions had slightly different shape parameters. The results for influenza A virus are remarkably similar to our own analysis of CirSeq-derived fitness values from poliovirus and previously published data from other small, single stranded DNA and RNA viruses. These data suggest that genome size, and not nucleic acid type or mode of replication, is the main determinant of viral mutational fitness effects. PMID:27571422

  4. Avian influenza virus and free-ranging wild birds

    USGS Publications Warehouse

    Dierauf, Leslie A.; Karesh, W.B.; Ip, Hon S.; Gilardi, K.V.; Fischer, John R.

    2006-01-01

    Recent media and news reports and other information implicate wild birds in the spread of highly pathogenic avian influenza in Asia and Eastern Europe. Although there is little information concerning highly pathogenic avian influenza viruses in wild birds, scientists have amassed a large amount of data on low-pathogenicity avian influenza viruses during decades of research with wild birds. This knowledge can provide sound guidance to veterinarians, public health professionals, the general public, government agencies, and other entities with concerns about avian influenza.

  5. Temporal association between the influenza virus and respiratory syncytial virus (RSV): RSV as a predictor of seasonal influenza.

    PubMed

    Míguez, A; Iftimi, A; Montes, F

    2016-09-01

    Epidemiologists agree that there is a prevailing seasonality in the presentation of epidemic waves of respiratory syncytial virus (RSV) infections and influenza. The aim of this study is to quantify the potential relationship between the activity of RSV, with respect to the influenza virus, in order to use the RSV seasonal curve as a predictor of the evolution of an influenza virus epidemic wave. Two statistical tools, logistic regression and time series, are used for predicting the evolution of influenza. Both logistic models and time series of influenza consider RSV information from previous weeks. Data consist of influenza and confirmed RSV cases reported in Comunitat Valenciana (Spain) during the period from week 40 (2010) to week 8 (2014). Binomial logistic regression models used to predict the two states of influenza wave, basal or peak, result in a rate of correct classification higher than 92% with the validation set. When a finer three-states categorization is established, basal, increasing peak and decreasing peak, the multinomial logistic model performs well in 88% of cases of the validation set. The ARMAX model fits well for influenza waves and shows good performance for short-term forecasts up to 3 weeks. The seasonal evolution of influenza virus can be predicted a minimum of 4 weeks in advance using logistic models based on RSV. It would be necessary to study more inter-pandemic seasons to establish a stronger relationship between the epidemic waves of both viruses. PMID:27165946

  6. Monitoring Avian Influenza A(H7N9) Virus through National Influenza-like Illness Surveillance, China

    PubMed Central

    Xu, Cuiling; Havers, Fiona; Wang, Lijie; Chen, Tao; Shi, Jinghong; Wang, Dayan; Yang, Jing; Yang, Lei; Widdowson, Marc-Alain

    2013-01-01

    In China during March 4–April 28, 2013, avian influenza A(H7N9) virus testing was performed on 20,739 specimens from patients with influenza-like illness in 10 provinces with confirmed human cases: 6 (0.03%) were positive, and increased numbers of unsubtypeable influenza-positive specimens were not seen. Careful monitoring and rapid characterization of influenza A(H7N9) and other influenza viruses remain critical. PMID:23879887

  7. Hemagglutination-inhibition assay for influenza virus subtype identification and the detection and quantitation of serum antibodies to influenza virus.

    PubMed

    Pedersen, Janice C

    2014-01-01

    Hemagglutination-inhibition (HI) assay is a classical laboratory procedure for the classification or subtyping of hemagglutinating viruses. For influenza virus, HI assay is used to identify the hemagglutinin (HA) subtype of an unknown isolate or the HA subtype specificity of antibodies to influenza virus. Since the HI assay is quantitative it is frequently applied to evaluate the antigenic relationships between different influenza virus isolates of the same subtype. The basis of the HI test is inhibition of hemagglutination with subtype-specific antibodies. The HI assay is a relatively inexpensive procedure utilizing standard laboratory equipment, is less technical than molecular tests, and is easily completed within several hours. However when working with uncharacterized viruses or antibody subtypes the library of reference reagents required for identifying antigenically distinct influenza viruses and or antibody specificities from multiple lineages of a single hemagglutinin subtype requires extensive laboratory support for the production and optimization of reagents. PMID:24899416

  8. Equine Influenza A(H3N8) Virus Infection in Cats

    PubMed Central

    Su, Shuo; Wang, Lifang; Fu, Xinliang; He, Shuyi; Hong, Malin; Zhou, Pei; Gray, Gregory

    2014-01-01

    Interspecies transmission of equine influenza A(H3N8) virus has resulted in establishment of a canine influenza virus. To determine if something similar could happen with cats, we experimentally infected 14 cats with the equine influenza A(H3N8) virus. All showed clinical signs, shed virus, and transmitted the virus to a contact cohort. PMID:25417790

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

    PubMed

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

    2015-12-01

    Influenza A virus (IAV) is characterized by eight single-stranded, negative sense RNA segments, which allows for gene reassortment among different IAV subtypes when they co-infect a single host cell simultaneously. Genetic reassortment is an important way to favor the evolution of influenza virus. Novel reassortant virus may pose a pandemic among humans. In history, three human pandemic influenza viruses were caused by genetic reassortment between avian, human and swine influenza viruses. Since 2009, pandemic (H1N1) 2009 (pdm/09 H1N1) influenza virus composed of two swine influenza virus genes highlighted the genetic reassortment again. Due to wide host species and high transmission of the pdm/09 H1N1 influenza virus, many different avian, human or swine influenza virus subtypes may reassert with it to generate novel reassortant viruses, which may result in a next pandemic among humans. So, it is necessary to understand the potential threat of current reassortant viruses between the pdm/09 H1N1 and other influenza viruses to public health. This study summarized the status of the reassortant viruses between the pdm/09 H1N1 and other influenza viruses of different species origins in natural and experimental conditions. The aim of this summarization is to facilitate us to further understand the potential threats of novel reassortant influenza viruses to public health and to make effective prevention and control strategies for these pathogens. PMID:26344393

  10. A Review of Evidence that Equine Influenza Viruses Are Zoonotic.

    PubMed

    Xie, Tai; Anderson, Benjamin D; Daramragchaa, Ulziimaa; Chuluunbaatar, Maitsetset; Gray, Gregory C

    2016-01-01

    Among scientists, there exist mixed opinions whether equine influenza viruses infect man. In this report, we summarize a 2016 systematic and comprehensive review of the English, Chinese, and Mongolian scientific literature regarding evidence for equine influenza virus infections in man. Searches of PubMed, Web of Knowledge, ProQuest, CNKI, Chongqing VIP Database, Wanfang Data and MongolMed yielded 2831 articles, of which 16 met the inclusion criteria for this review. Considering these 16 publications, there was considerable experimental and observational evidence that at least H3N8 equine influenza viruses have occasionally infected man. In this review we summarize the most salient scientific reports. PMID:27420100

  11. Differential age susceptibility to influenza B/Victoria lineage viruses in the 2015 Australian influenza season.

    PubMed

    Barr, Ian G; Vijaykrishna, Dhanasekaran; Sullivan, Sheena G

    2016-01-01

    Influenza B viruses make up an important part of the burden from seasonal influenza globally. The 2015 season in Australia saw an unusual predominance of influenza B with a distinctive switch during the season from B/Yamagata/16/88 lineage viruses to B/Victoria/2/87 lineage viruses. We also noted significant differences in the age groups infected by the different B lineages, with B/Victoria infecting a younger population than B/Yamagata, that could not be explained by potential prior exposure. PMID:26848118

  12. Rewiring the RNAs of influenza virus to prevent reassortment

    PubMed Central

    Gao, Qinshan; Palese, Peter

    2009-01-01

    Influenza viruses contain segmented, negative-strand RNA genomes. Genome segmentation facilitates reassortment between different influenza virus strains infecting the same cell. This phenomenon results in the rapid exchange of RNA segments. In this study, we have developed a method to prevent the free reassortment of influenza A virus RNAs by rewiring their packaging signals. Specific packaging signals for individual influenza virus RNA segments are located in the 5′ and 3′ noncoding regions as well as in the terminal regions of the ORF of an RNA segment. By putting the nonstructural protein (NS)-specific packaging sequences onto the ORF of the hemagglutinin (HA) gene and mutating the packaging regions in the ORF of the HA, we created a chimeric HA segment with the packaging identity of an NS gene. By the same strategy, we made an NS gene with the packaging identity of an HA segment. This rewired virus had the packaging signals for all eight influenza virus RNAs, but it lost the ability to independently reassort its HA or NS gene. A similar approach can be applied to the other influenza A virus segments to diminish their ability to form reassortant viruses. PMID:19805230

  13. Molecular analysis of a haemagglutinin of Haemophilus paragallinarum.

    PubMed

    Hobb, Rhonda I; Tseng, Hsing-Ju; Downes, John E; Terry, Tamsin D; Blackall, Patrick J; Takagi, Masami; Jennings, Michael P

    2002-07-01

    The gene encoding a haemagglutinin of H. paragallinarum, hagA, has been identified and the full-length nucleotide sequence determined. A approximately 39 kDa protein, recognized by an anti-haemagglutinin monoclonal antibody, mAb4D, was purified from H. paragallinarum strain 0083 and the N-terminal sequence obtained. The full-length nucleotide sequence was obtained by inverse PCR and the deduced amino acid sequence of the protein encoded was shown to be similar to other outer-membrane proteins of closely related organisms in the HAP group (Haemophilus, Actinobacillus, Pasteurella), especially the P5 protein of Haemophilus influenzae. The hagA gene was cloned into a His-tag expression vector and overexpressed in Escherichia coli strain M15(pREP4). The identity of the purified recombinant protein as a H. paragallinarum haemagglutinin was confirmed by haemagglutination of chicken red blood cells and reactivity, in a Western blot, with the monoclonal antibody specific for the serovar A haemagglutinin. PMID:12101304

  14. Pathobiology of avian influenza virus infections in wild birds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Individual avian Influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological features in chickens, AI viruses (AIV) are categorized as low pathogenicity (LPAI) or high pathogenicity (HPAI) viruses, and can be of any of...

  15. Influenza A virus in swine - moving beyond 2009

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Surveillance for influenza A viruses (IAV) circulating in pigs and other non-human mammals has been chronically underfunded and virtually nonexistent in many areas of the world [1]. This deficit is in spite of our knowledge that influenza is a disease shared between man and pig from at...

  16. Influenza A virus pathogenesis and vaccination in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Practical aspects of vaccination of poultry against avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although little has changed in vaccine technology for avian influenza virus (AIV) in the past 20 years, the approach to vaccination of poultry (chickens, turkeys and ducks) for avian influenza has evolved as highly pathogenic (HP) AIV has become endemic in several regions of the world. Vaccination f...

  18. Characterization of Potent Fusion Inhibitors of Influenza Virus

    PubMed Central

    Rowse, Michael; Qiu, Shihong; Tsao, Jun; Xian, Tongmei; Khawaja, Sarah; Yamauchi, Yohei; Yang, Zhen; Wang, Guoxin; Luo, Ming

    2015-01-01

    New inhibitors of influenza viruses are needed to combat the potential emergence of novel human influenza viruses. We have identified a class of small molecules that inhibit replication of influenza virus at picomolar concentrations in plaque reduction assays. The compound also inhibits replication of vesicular stomatitis virus. Time of addition and dilution experiments with influenza virus indicated that an early time point of infection was blocked and that inhibitor 136 tightly bound to virions. Using fluorescently labeled influenza virus, inhibition of viral fusion to cellular membranes by blocked lipid mixing was established as the mechanism of action for this class of inhibitors. Stabilization of the neutral pH form of hemagglutinin (HA) was ruled out by trypsin digestion studies in vitro and with conformation specific HA antibodies within cells. Direct visualization of 136 treated influenza virions at pH 7.5 or acidified to pH 5.0 showed that virions remain intact and that glycoproteins become disorganized as expected when HA undergoes a conformational change. This suggests that exposure of the fusion peptide at low pH is not inhibited but lipid mixing is inhibited, a different mechanism than previously reported fusion inhibitors. We hypothesize that this new class of inhibitors intercalate into the virus envelope altering the structure of the viral envelope required for fusion to cellular membranes. PMID:25803288

  19. Characterization of potent fusion inhibitors of influenza virus.

    PubMed

    Rowse, Michael; Qiu, Shihong; Tsao, Jun; Xian, Tongmei; Khawaja, Sarah; Yamauchi, Yohei; Yang, Zhen; Wang, Guoxin; Luo, Ming

    2015-01-01

    New inhibitors of influenza viruses are needed to combat the potential emergence of novel human influenza viruses. We have identified a class of small molecules that inhibit replication of influenza virus at picomolar concentrations in plaque reduction assays. The compound also inhibits replication of vesicular stomatitis virus. Time of addition and dilution experiments with influenza virus indicated that an early time point of infection was blocked and that inhibitor 136 tightly bound to virions. Using fluorescently labeled influenza virus, inhibition of viral fusion to cellular membranes by blocked lipid mixing was established as the mechanism of action for this class of inhibitors. Stabilization of the neutral pH form of hemagglutinin (HA) was ruled out by trypsin digestion studies in vitro and with conformation specific HA antibodies within cells. Direct visualization of 136 treated influenza virions at pH 7.5 or acidified to pH 5.0 showed that virions remain intact and that glycoproteins become disorganized as expected when HA undergoes a conformational change. This suggests that exposure of the fusion peptide at low pH is not inhibited but lipid mixing is inhibited, a different mechanism than previously reported fusion inhibitors. We hypothesize that this new class of inhibitors intercalate into the virus envelope altering the structure of the viral envelope required for fusion to cellular membranes. PMID:25803288

  20. Influenza virus hemagglutinin stalk-based antibodies and vaccines

    PubMed Central

    Krammer, Florian; Palese, Peter

    2013-01-01

    Antibodies against the conserved stalk domain of the hemagglutinin are currently being discussed as promising therapeutic tools against influenza virus infections. Due to the conservation of the stalk domain these antibodies are able to broadly neutralize a wide spectrum of influenza virus strains and subtypes. Broadly protective vaccine candidates based on the epitopes of these antibodies, e.g. chimeric and headless hemagglutinin structures, are currently under development and show promising results in animals models. These candidates could be developed into universal influenza virus vaccines that protect from infection with drifted seasonal as well as novel pandemic influenza virus strains therefore obviating the need for annual vaccination, and enhancing our pandemic preparedness. PMID:23978327

  1. The haemagglutinin gene, but not the neuraminidase gene, of 'Spanish flu' was a recombinant.

    PubMed Central

    Gibbs, M J; Armstrong, J S; Gibbs, A J

    2001-01-01

    Published analyses of the sequences of three genes from the 1918 Spanish influenza virus have cast doubt on the theory that it came from birds immediately before the pandemic. They showed that the virus was of the H1N1 subtype lineage but more closely related to mammal-infecting strains than any known bird-infecting strain. They provided no evidence that the virus originated by gene reassortment nor that the virus was the direct ancestor of the two lineages of H1N1 viruses currently found in mammals; one that mostly infects human beings, the other pigs. The unusual virulence of the virus and why it produced a pandemic have remained unsolved. We have reanalysed the sequences of the three 1918 genes and found conflicting patterns of relatedness in all three. Various tests showed that the patterns in its haemagglutinin (HA) gene were produced by true recombination between two different parental HA H1 subtype genes, but that the conflicting patterns in its neuraminidase and non-structural-nuclear export proteins genes resulted from selection. The recombination event that produced the 1918 HA gene probably coincided with the start of the pandemic, and may have triggered it. PMID:11779383

  2. Isolation of influenza viruses in MDCK 33016PF cells and clearance of contaminating respiratory viruses.

    PubMed

    Roth, Bernhard; Mohr, Hannah; Enders, Martin; Garten, Wolfgang; Gregersen, Jens-Peter

    2012-01-11

    This paper summarizes results obtained by multiplex PCR screening of human clinical samples for respiratory viruses and corresponding data obtained after passaging of virus-positive samples in MDCK 33016PF cells. Using the ResPlexII v2.0 (Qiagen) multiplex PCR, 393 positive results were obtained in 468 clinical samples collected during an influenza season in Germany. The overall distribution of positive results was influenza A 42.0%, influenza B 38.7%, adenovirus 1.5%, bocavirus 0.5%, coronavirus 3.3%, enterovirus 5.6%, metapneumovirus 1.0%, parainfluenza virus 0.8%, rhinovirus 4.1%, and respiratory syncytial virus (RSV) 2.5%. Double infections of influenza virus together with another virus were found for adenovirus B and E, bocavirus, coronavirus, enterovirus and for rhinovirus. These other viruses were rapidly lost upon passages in MDCK 33016PF cells and under conditions as applied to influenza virus passaging. Clinical samples, in which no influenza virus but other viruses were found, were also subject to passages in MDCK 33016PF cells. Using lower inoculum dilutions than those normally applied for preparations containing influenza virus (total dilution of the original sample of ∼10(4)), the positive results for the different viruses turned negative already after 2 or 3 passages in MDCK 33016PF cells. These results demonstrate that, under practical conditions as applied to grow influenza viruses, contaminating viruses can be effectively removed by passages in MDCK cells. In combination with their superior isolation efficiency, MDCK cells appear highly suitable to be used as an alternative to embryonated eggs to isolate and propagate influenza vaccine candidate viruses. PMID:22119922

  3. Isolation and characterization of pandemic H1N1 influenza viruses in pigs in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A virus (IAV) infections are endemic diseases in pork producing countries around the world. The emergence of the pandemic 2009 human H1N1 influenza A virus (pH1N1) raised questions about the occurrence of this virus in Brazilian swine populations. During a 2009-2010 swine influenza virus r...

  4. VIRAPOPS2 supports the influenza virus reassortments

    PubMed Central

    2014-01-01

    Background For over 400 years, due to the reassortment of their segmented genomes, influenza viruses evolve extremely quickly and cause devastating epidemics. This reassortment arises because two flu viruses can infect the same cell and therefore the new virions’ genomes will be composed of segment reassortments of the two parental strains. A treatment developed against parents could then be ineffective if the virions’ genomes are different enough from their parent’s genomes. It is therefore essential to simulate such reassortment phenomena to assess the risk of apparition of new flu strain. Findings So we decided to upgrade the forward simulator VIRAPOPS, containing already the necessary options to handle non-segmented viral populations. This new version can mimic single or successive reassortments, in birds, humans and/or swines. Other options such as the ability to treat populations of positive or negative sense viral RNAs, were also added. Finally, we propose output options giving statistics of the results. Conclusion In this paper we present a new version of VIRAPOPS which now manages the viral segment reassortments and the negative sense single strain RNA viruses, these two issues being the cause of serious public health problems. PMID:25183993

  5. Visible light powered self-disinfecting coatings for influenza viruses

    NASA Astrophysics Data System (ADS)

    Weng, Ding; Qi, Hangfei; Wu, Ting-Ting; Yan, Ming; Sun, Ren; Lu, Yunfeng

    2012-04-01

    Influenza A viruses, the pathogens responsible for the recent swine flu outbreak and many historical pandemics, remain a threat to the public health. We report herein the fabrication of self-disinfecting surfaces from photoactive building nanocrystals, which can inactivate influenza viruses rapidly, spontaneously and continuously under visible light illumination.Influenza A viruses, the pathogens responsible for the recent swine flu outbreak and many historical pandemics, remain a threat to the public health. We report herein the fabrication of self-disinfecting surfaces from photoactive building nanocrystals, which can inactivate influenza viruses rapidly, spontaneously and continuously under visible light illumination. Electronic supplementary information (ESI) available: XRD, UV-Vis absorbance, TEM, AFM of as-prepared nanocrystals and as-fabricated self-disinfecting surfaces, disinfection of influenza A virus by TiO2 (P25) with UV irradiation as reference control, photoinactivation of influenza A virus envelope proteins and photoinactivation of trypsin. See DOI: 10.1039/c2nr30388d

  6. Pathogenesis of influenza: virus-host interactions.

    PubMed

    Godlee, Alexandra; Almond, Mark H; Dong, Tao

    2011-08-01

    Since their inception in March 1972, Keystone Symposia on Molecular and Cellular Biology have brought together scientists from across the globe to discuss key biological topics. Now in its 40th year, it is a completely independent, nonprofit organization devoted solely to providing outstanding scientific conferences in all areas of the biological and biomedical sciences. Towards the end of May 2011, over 200 virologists and immunologists came to Hong Kong, an appropriate setting given the emergence of H5N1, to discuss influenza virus and host interactions. The meeting, expertly organized by Siamon Gordon (University of Oxford, Oxofrd, UK), Malik Peiris (University of Hong Kong, Hong Kong, China) and Kanta Subbarao (NIAID, NIH, MD, USA), took place in the aftermath of the first pandemic in 40 years and provided great insight into both pandemic H1N1 and H5N1. This article focuses on some of the recurring themes that were discussed during the week. PMID:21819324

  7. Influenza virus inhibits ENaC and lung fluid clearance.

    PubMed

    Chen, Xi-Juan; Seth, Shaguna; Yue, Gang; Kamat, Pradip; Compans, Richard W; Guidot, David; Brown, Lou Ann; Eaton, Douglas C; Jain, Lucky

    2004-08-01

    Fluid-free alveolar space is critical for normal gas exchange. Influenza virus alters fluid transport across respiratory epithelia producing rhinorrhea, middle ear effusions, and alveolar flooding. However, the mechanism of fluid retention remains unclear. We investigated influenza virus strain A/PR/8/34, which can attach and enter mammalian cells but is incapable of viral replication and productive infection in mammalian epithelia, on epithelial sodium channels (ENaC) in rat alveolar type II (ATII) cells. In parallel, we determined the effects of virus on amiloride-sensitive (i.e., ENaC-mediated) fluid clearance in rat lungs in vivo. Although influenza virus did not change the inulin permeability of ATII monolayers, it rapidly reduced the net volume transport across monolayers. Virus reduced the open probability of single ENaC channels in apical cell-attached patches. U-73122, a phospholipase C (PLC) inhibitor, and PP2, a Src inhibitor, blocked the effect of virus on ENaC. GF-109203X, a protein kinase C (PKC) inhibitor, also blocked the effect, suggesting a PKC-mediated mechanism. In parallel, intratracheal administration of influenza virus produced a rapid inhibition of amiloride-sensitive (i.e., ENaC-dependent) lung fluid transport. Together, these results show that influenza virus rapidly inhibits ENaC in ATII cells via a PLC- and Src-mediated activation of PKC but does not increase epithelial permeability in this same rapid time course. We speculate that this rapid inhibition of ENaC and formation of edema when the virus first attaches to the alveolar epithelium might facilitate subsequent influenza infection and may exacerbate influenza-mediated alveolar flooding that can lead to acute respiratory failure and death. PMID:15121635

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

    PubMed Central

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

    2010-01-01

    Triple-reassortant swine influenza viruses circulating in North American pigs contain the internal genes derived from swine (matrix, non-structural and nucleoprotein), human [polymerase basic 1 (PB1)] and avian (polymerase acidic and PB2) influenza viruses forming a constellation of genes that is well conserved and is called the triple-reassortant internal gene (TRIG) cassette. In contrast, the external genes [haemagglutinin (HA) and neuraminidase (NA)] are less conserved, reflecting multiple reassortant events that have produced viruses with different combinations of HA and NA genes. This study hypothesized that maintenance of the TRIG cassette confers a selective advantage to the virus. To test this hypothesis, pigs were co-infected with the triple-reassortant H3N2 A/Swine/Texas/4199-2/98 (Tx/98) and the classical H1N1 A/Swine/Iowa/15/1930 viruses and co-housed with a group of sentinel animals. This direct contact group was subsequently moved into contact with a second group of naïve animals. Four different subtypes (H1N1, H1N2, H3N1 and H3N2) of influenza virus were identified in bronchoalveolar lavage fluid collected from the lungs of the experimentally infected pigs, with most of the viruses containing TRIG from the Tx/98 virus. Interestingly, only the intact H3N2 Tx/98 virus was transmitted from the infected pigs to the direct-contact animals and from them to the second contact group of pigs. These results demonstrated that multiple reassortments can occur within a host; however, only specific gene constellations are readily transmissible. It was concluded that certain HA and NA gene pairs, in conjunction with the TRIG cassette, may have a competitive advantage over other combinations for transmission and maintenance in swine. PMID:20484565

  9. A combination in-ovo vaccine for avian influenza virus and Newcastle disease virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The protection of poultry from H5N1 highly pathogenic avian influenza A (HPAI) and Newcastle disease virus (NDV) can be achieved through vaccination, as part of a broader disease control strategy. We have previously generated a recombinant influenza virus expressing; (i) an H5N1 hemagglutinin protei...

  10. Adenovirus as a carrier for the development of influenza virus-free avian influenza vaccines

    PubMed Central

    Tang, De-chu C; Zhang, Jianfeng; Toro, Haroldo; Shi, Zhongkai; Van Kampen, Kent R

    2009-01-01

    A long-sought goal during the battle against avian influenza is to develop a new generation of vaccines capable of mass immunizing humans as well as poultry (the major source of avian influenza for human infections) in a timely manner. Although administration of the currently licensed influenza vaccine is effective in eliciting protective immunity against seasonal influenza, this approach is associated with a number of insurmountable problems for preventing an avian influenza pandemic. Many of the hurdles may be eliminated by developing new avian influenza vaccines that do not require the propagation of an influenza virus during vaccine production. Replication-competent adenovirus-free adenovirus vectors hold promise as a carrier for influenza virus-free avian influenza vaccines owing to their safety profile and rapid manufacture using cultured suspension cells in a serum-free medium. Simple and efficient mass-immunization protocols, including nasal spray for people and automated in ovo vaccination for poultry, convey another advantage for this class of vaccines. In contrast to parenteral injection of adenovirus vector, the potency of adenovirus-vectored nasal vaccine is not appreciably interfered by pre-existing immunity to adenovirus. PMID:19348562

  11. The Influenza NS1 Protein: What Do We Know in Equine Influenza Virus Pathogenesis?

    PubMed

    Barba, Marta; Daly, Janet M

    2016-01-01

    Equine influenza virus remains a serious health and potential economic problem throughout most parts of the world, despite intensive vaccination programs in some horse populations. The influenza non-structural protein 1 (NS1) has multiple functions involved in the regulation of several cellular and viral processes during influenza infection. We review the strategies that NS1 uses to facilitate virus replication and inhibit antiviral responses in the host, including sequestering of double-stranded RNA, direct modulation of protein kinase R activity and inhibition of transcription and translation of host antiviral response genes such as type I interferon. Details are provided regarding what it is known about NS1 in equine influenza, especially concerning C-terminal truncation. Further research is needed to determine the role of NS1 in equine influenza infection, which will help to understand the pathophysiology of complicated cases related to cytokine imbalance and secondary bacterial infection, and to investigate new therapeutic and vaccination strategies. PMID:27589809

  12. A Defective Interfering Influenza RNA Inhibits Infectious Influenza Virus Replication in Human Respiratory Tract Cells: A Potential New Human Antiviral.

    PubMed

    Smith, Claire M; Scott, Paul D; O'Callaghan, Christopher; Easton, Andrew J; Dimmock, Nigel J

    2016-01-01

    Defective interfering (DI) viruses arise during the replication of influenza A virus and contain a non-infective version of the genome that is able to interfere with the production of infectious virus. In this study we hypothesise that a cloned DI influenza A virus RNA may prevent infection of human respiratory epithelial cells with infection by influenza A. The DI RNA (244/PR8) was derived by a natural deletion process from segment 1 of influenza A/PR/8/34 (H1N1); it comprises 395 nucleotides and is packaged in the DI virion in place of a full-length genome segment 1. Given intranasally, 244/PR8 DI virus protects mice and ferrets from clinical influenza caused by a number of different influenza A subtypes and interferes with production of infectious influenza A virus in cells in culture. However, evidence that DI influenza viruses are active in cells of the human respiratory tract is lacking. Here we show that 244/PR8 DI RNA is replicated by an influenza A challenge virus in human lung diploid fibroblasts, bronchial epithelial cells, and primary nasal basal cells, and that the yield of challenge virus is significantly reduced in a dose-dependent manner indicating that DI influenza virus has potential as a human antiviral. PMID:27556481

  13. A Defective Interfering Influenza RNA Inhibits Infectious Influenza Virus Replication in Human Respiratory Tract Cells: A Potential New Human Antiviral

    PubMed Central

    Smith, Claire M.; Scott, Paul D.; O’Callaghan, Christopher; Easton, Andrew J.; Dimmock, Nigel J.

    2016-01-01

    Defective interfering (DI) viruses arise during the replication of influenza A virus and contain a non-infective version of the genome that is able to interfere with the production of infectious virus. In this study we hypothesise that a cloned DI influenza A virus RNA may prevent infection of human respiratory epithelial cells with infection by influenza A. The DI RNA (244/PR8) was derived by a natural deletion process from segment 1 of influenza A/PR/8/34 (H1N1); it comprises 395 nucleotides and is packaged in the DI virion in place of a full-length genome segment 1. Given intranasally, 244/PR8 DI virus protects mice and ferrets from clinical influenza caused by a number of different influenza A subtypes and interferes with production of infectious influenza A virus in cells in culture. However, evidence that DI influenza viruses are active in cells of the human respiratory tract is lacking. Here we show that 244/PR8 DI RNA is replicated by an influenza A challenge virus in human lung diploid fibroblasts, bronchial epithelial cells, and primary nasal basal cells, and that the yield of challenge virus is significantly reduced in a dose-dependent manner indicating that DI influenza virus has potential as a human antiviral. PMID:27556481

  14. Construction and Characterization of an Infectious Vaccinia Virus Recombinant That Expresses the Influenza Hemagglutinin Gene and Induces Resistance to Influenza Virus Infection in Hamsters

    NASA Astrophysics Data System (ADS)

    Smith, Geoffrey L.; Murphy, Brian R.; Moss, Bernard

    1983-12-01

    A DNA copy of the influenza virus hemagglutinin gene, derived from influenza virus A/Jap/305/57 (H2N2) was inserted into the genome of vaccinia virus under the control of an early vaccinia virus promoter. Tissue culture cells infected with the purified recombinant virus synthesized influenza hemagglutinin, which was glycosylated and transported to the cell surface where it could be cleaved with trypsin into HA1 and HA2 subunits. Rabbits and hamsters inoculated intradermally with recombinant virus produced circulating antibodies that inhibited hemagglutination by influenza virus. Furthermore, vaccinated hamsters achieved levels of antibody similar to those obtained upon primary infection with influenza virus and were protected against respiratory infection with the A/Jap/305/57 influenza virus.

  15. Direct detection of influenza virus antigen in nasopharyngeal specimens by direct enzyme immunoassay in comparison with quantitating virus shedding.

    PubMed Central

    Döller, G; Schuy, W; Tjhen, K Y; Stekeler, B; Gerth, H J

    1992-01-01

    We developed a direct enzyme immunoassay [EIA; Enzygnost Influenza A(Ag) and Enzygnost Influenza B(Ag)] for the direct detection of influenza A and B virus antigens in nasopharyngeal secretion specimens (NPS). The test is performed without sonification of specimens, and results are obtained within 4 h. A direct comparison between direct EIA and quantitation of virus shedding for influenza A and B virus antigen detection was carried out. A total of 210 NPS and 98 nasopharyngeal wash specimens (NPW) were investigated. We isolated influenza A viruses from 79 (37.6%) of 210 NPS; of these 79 cell-culture-positive NPS, 70 (88.6%) were also positive by direct EIA. Of 29 (13.8%) NPS from which influenza B virus was isolated, 24 (82.8%) NPS were positive by direct EIA. Virus shedding was determined quantitatively in 48 NPS from patients with influenza A and in 24 NPS from patients with influenza B. Only a crude correlation between optical density values and virus concentrations was observed. Detection of influenza virus antigens in NPS by direct EIA showed sensitivities of 89.7% for influenza A virus and 87.9% for influenza B virus and specificities of 99.3% for influenza A virus and 100% for influenza B virus. With direct EIA, all NPW were negative for influenza A virus, although virus was isolated from 21 (21.4%) NPW. Of 15 NPW from which influenza B virus was isolated, 7 showed positive results in direct EIA. In addition, direct EIA is suitable for detecting influenza A and B viruses in cell cultures before the appearance of any cytopathic effects and can be used as a cell culture confirmation test. PMID:1572972

  16. Derivatives of 3:4-xylidine and related compounds as inhibitors of influenza virus: relationships between chemical structure and biological activity

    PubMed Central

    Clark, R. J.; Isaacs, A.; Walker, J.

    1958-01-01

    A series of compounds, based primarily on 3:4-xylidine, was examined for inhibitory activity towards the growth of influenza virus in tissue culture. Marked dependence of inhibitory activity upon chemical structure was observed particularly when the 3:4-xylyl group was replaced by other simple aryl radicals. N-(2-Piperidinoethyl)-3:4-xylidine dihydrochloride, a typical compound combining high intrinsic inhibitory activity with no obvious toxicity towards the host tissues, did not inactivate the virus directly before its adsorption, did not interfere with adsorption of virus by the tissues, and did not inhibit the release of freshly synthesized virus by the tissues, but specifically depressed the synthesis of viral haemagglutinin to a greater extent than it depressed the synthesis of complement-fixing soluble antigen. The inhibition of growth of influenza virus caused by this compound in tissue culture was reversed by appropriate addition of 4:5-dimethyl-o-phenylenediamine, but not apparently by riboflavin or by vitamin B12. The action of this substance, and, by inference, of related compounds, in inhibiting viral synthesis may be the result of depressed cytoplasmic protein synthesis. PMID:13618548

  17. Animal models for influenza virus transmission studies: A historical perspective

    PubMed Central

    Bouvier, Nicole M.

    2015-01-01

    Animal models are used to simulate, under experimental conditions, the complex interactions among host, virus, and environment that affect the person-to-person spread of influenza viruses. The three species that have been most frequently employed, both past and present, as influenza virus transmission models -- ferrets, mice, and guinea pigs -- have each provided unique insights into the factors governing the efficiency with which these viruses pass from an infected host to a susceptible one. This review will highlight a few of these noteworthy discoveries, with a particular focus on the historical contexts in which each model was developed and the advantages and disadvantages of each species with regard to the study of influenza virus transmission among mammals. PMID:26126082

  18. Neuraminidase Resistant Sialosides for the Detection of Influenza Viruses.

    PubMed

    He, Yun; Yang, Yang; Iyer, Suri S

    2016-06-15

    We report the synthesis of influenza virus neuraminidase (NA) resistant sialosides that include different glycoside linkages (C-, S-, and triazole). These unnatural sialosides were printed onto glass slides to generate a small focused microarray. We evaluated the binding affinity of multiple lectins and compared the stability of these sialosides with O-linked sialosides toward influenza virus neuraminidase and intact virus. We demonstrated the ability of these molecules to capture eight different strains of influenza virus at ambient temperature without the addition of NA inhibitors. The glycans capture extremely low, clinically relevant concentrations of viruses and each strain gives rise to a specific "fingerprint" binding pattern, which could potentially be used in rapid diagnostic tests. PMID:27139196

  19. Persistence of Highly Pathogenic Avian Influenza Viruses in Natural Ecosystems

    PubMed Central

    Feare, Chris J.; Renaud, François; Thomas, Frédéric; Gauthier-Clerc, Michel

    2010-01-01

    Understanding of ecologic factors favoring emergence and maintenance of highly pathogenic avian influenza (HPAI) viruses is limited. Although low pathogenic avian influenza viruses persist and evolve in wild populations, HPAI viruses evolve in domestic birds and cause economically serious epizootics that only occasionally infect wild populations. We propose that evolutionary ecology considerations can explain this apparent paradox. Host structure and transmission possibilities differ considerably between wild and domestic birds and are likely to be major determinants of virulence. Because viral fitness is highly dependent on host survival and dispersal in nature, virulent forms are unlikely to persist in wild populations if they kill hosts quickly or affect predation risk or migratory performance. Interhost transmission in water has evolved in low pathogenic influenza viruses in wild waterfowl populations. However, oropharyngeal shedding and transmission by aerosols appear more efficient for HPAI viruses among domestic birds. PMID:20587174

  20. The global antigenic diversity of swine influenza A viruses

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-15

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

  2. Challenge of Pigs with Natural Immunity to H1 and H3 Swine Influenza Virus with Pandemic 2009 H1N1 Influenza Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction. The emergence of the pandemic 2009 human H1N1 influenza A virus raised many questions about the implications for this virus in swine (1). One such question is, does prior exposure to influenza virus confer any protection against the new virus? This report describes a study to evaluate ...

  3. Influenza.

    PubMed

    Labella, Angelena M; Merel, Susan E

    2013-07-01

    Influenza is a common virus whose ability to change its genetic makeup allows for disease of pandemic proportion. This article summarizes the different strains of influenza circulating in the United States for the past century, the diagnosis and treatment of influenza, as well as the different ways to prevent disease. This information will be of value to clinicians caring for patients both in the hospital and in the community. PMID:23809717

  4. No Serological Evidence that Harbour Porpoises Are Additional Hosts of Influenza B Viruses

    PubMed Central

    Bodewes, Rogier; van de Bildt, Marco W. G.; van Elk, Cornelis E.; Bunskoek, Paulien E.; van de Vijver, David A. M. C.; Smits, Saskia L.; Osterhaus, Albert D. M. E.; Kuiken, Thijs

    2014-01-01

    Influenza A and B viruses circulate among humans causing epidemics almost annually. While various hosts for influenza A viruses exist, influenza B viruses have been detected only in humans and seals. However, recurrent infections of seals in Dutch coastal waters with influenza B viruses that are antigenetically distinct from influenza B viruses circulating among humans suggest that influenza B viruses have been introduced into this seal population by another, non-human, host. Harbour porpoises (Phocoena phocoena) are sympatric with seals in these waters and are also occasionally in close contact with humans after stranding and subsequent rehabilitation. In addition, virus attachment studies demonstrated that influenza B viruses can bind to cells of the respiratory tract of these animals. Therefore, we hypothesized that harbour porpoises might be a reservoir of influenza B viruses. In the present study, an unique set of serum samples from 79 harbour porpoises, stranded alive on the Dutch coast between 2003 and 2013, was tested for the presence of antibodies against influenza B viruses by use of the hemagglutination inhibition test and for antibodies against influenza A viruses by use of a competitive influenza A nucleoprotein ELISA. No antibodies were detected against either virus, suggesting that influenza A and B virus infections of harbour porpoises in Dutch coastal waters are not common, which was supported by statistical analysis of the dataset. PMID:24551217

  5. No serological evidence that harbour porpoises are additional hosts of influenza B viruses.

    PubMed

    Bodewes, Rogier; van de Bildt, Marco W G; van Elk, Cornelis E; Bunskoek, Paulien E; van de Vijver, David A M C; Smits, Saskia L; Osterhaus, Albert D M E; Kuiken, Thijs

    2014-01-01

    Influenza A and B viruses circulate among humans causing epidemics almost annually. While various hosts for influenza A viruses exist, influenza B viruses have been detected only in humans and seals. However, recurrent infections of seals in Dutch coastal waters with influenza B viruses that are antigenetically distinct from influenza B viruses circulating among humans suggest that influenza B viruses have been introduced into this seal population by another, non-human, host. Harbour porpoises (Phocoena phocoena) are sympatric with seals in these waters and are also occasionally in close contact with humans after stranding and subsequent rehabilitation. In addition, virus attachment studies demonstrated that influenza B viruses can bind to cells of the respiratory tract of these animals. Therefore, we hypothesized that harbour porpoises might be a reservoir of influenza B viruses. In the present study, an unique set of serum samples from 79 harbour porpoises, stranded alive on the Dutch coast between 2003 and 2013, was tested for the presence of antibodies against influenza B viruses by use of the hemagglutination inhibition test and for antibodies against influenza A viruses by use of a competitive influenza A nucleoprotein ELISA. No antibodies were detected against either virus, suggesting that influenza A and B virus infections of harbour porpoises in Dutch coastal waters are not common, which was supported by statistical analysis of the dataset. PMID:24551217

  6. Influenza virus reservoirs and intermediate hosts: dogs, horses, and new possibilities for influenza virus exposure of humans.

    PubMed

    Parrish, Colin R; Murcia, Pablo R; Holmes, Edward C

    2015-03-01

    Influenza A virus (IAV) infections in hosts outside the main aquatic bird reservoirs occur periodically. Although most such cross-species transmission events result in limited onward transmission in the new host, sustained influenza outbreaks have occurred in poultry and in a number of mammalian species, including humans, pigs, horses, seals, and mink. Recently, two distinct strains of IAV have emerged in domestic dogs, with each circulating widely for several years. Here, we briefly outline what is known about the role of intermediate hosts in influenza emergence, summarize our knowledge of the new canine influenza viruses (CIVs) and how they provide key new information on the process of host adaptation, and assess the risk these viruses pose to human populations. PMID:25540375

  7. A Novel Influenza Virus Hemagglutinin-Respiratory Syncytial Virus (RSV) Fusion Protein Subunit Vaccine against Influenza and RSV

    PubMed Central

    Turner, Tiffany M.; Jones, Les P.; Tompkins, S. Mark

    2013-01-01

    Influenza A virus and respiratory syncytial virus (RSV) cause substantial morbidity and mortality afflicting the ends of the age spectrum during the autumn through winter months in the United States. The benefit of vaccination against RSV and influenza using a subunit vaccine to enhance immunity and neutralizing antibody was investigated. Influenza virus hemagglutinin (HA) and RSV fusion (F) protein were tested as vaccine components alone and in combination to explore the adjuvant properties of RSV F protein on HA immunity. Mice vaccinated with HA and F exhibited robust immunity that, when challenged, had reduced viral burden for both influenza and RSV. These studies show an enhancing and cross-protective benefit of F protein for anti-HA immunity. PMID:23903841

  8. Influenza Virus Reservoirs and Intermediate Hosts: Dogs, Horses, and New Possibilities for Influenza Virus Exposure of Humans

    PubMed Central

    Murcia, Pablo R.; Holmes, Edward C.

    2014-01-01

    Influenza A virus (IAV) infections in hosts outside the main aquatic bird reservoirs occur periodically. Although most such cross-species transmission events result in limited onward transmission in the new host, sustained influenza outbreaks have occurred in poultry and in a number of mammalian species, including humans, pigs, horses, seals, and mink. Recently, two distinct strains of IAV have emerged in domestic dogs, with each circulating widely for several years. Here, we briefly outline what is known about the role of intermediate hosts in influenza emergence, summarize our knowledge of the new canine influenza viruses (CIVs) and how they provide key new information on the process of host adaptation, and assess the risk these viruses pose to human populations. PMID:25540375

  9. Replication-competent fluorescent-expressing influenza B virus.

    PubMed

    Nogales, Aitor; Rodríguez-Sánchez, Irene; Monte, Kristen; Lenschow, Deborah J; Perez, Daniel R; Martínez-Sobrido, Luis

    2016-02-01

    Influenza B viruses (IBVs) cause annual outbreaks of respiratory illness in humans and are increasingly recognized as a major cause of influenza-associated morbidity and mortality. Studying influenza viruses requires the use of secondary methodologies to identify virus-infected cells. To this end, replication-competent influenza A viruses (IAVs) expressing easily traceable fluorescent proteins have been recently developed. In contrast, similar approaches for IBV are mostly lacking. In this report, we describe the generation and characterization of replication-competent influenza B/Brisbane/60/2008 viruses expressing fluorescent mCherry or GFP fused to the C-terminal of the viral non-structural 1 (NS1) protein. Fluorescent-expressing IBVs display similar growth kinetics and plaque phenotype to wild-type IBV, while fluorescent protein expression allows for the easy identification of virus-infected cells. Without the need of secondary approaches to monitor viral infection, fluorescent-expressing IBVs represent an ideal approach to study the biology of IBV and an excellent platform for the rapid identification and characterization of antiviral therapeutics or neutralizing antibodies using high-throughput screening approaches. Lastly, fluorescent-expressing IBVs can be combined with the recently described reporter-expressing IAVs for the identification of novel therapeutics to combat these two important human respiratory pathogens. PMID:26590325

  10. Replication-competent fluorescent-expressing influenza B virus

    PubMed Central

    Nogales, Aitor; Rodríguez-Sánchez, Irene; Monte, Kristen; Lenschow, Deborah J.; Perez, Daniel R.; Martínez-Sobrido, Luis

    2016-01-01

    Influenza B viruses (IBVs) cause annual outbreaks of respiratory illness in humans and are increasingly recognized as a major cause of influenza-associated morbidity and mortality. Studying influenza viruses requires the use of secondary methodologies to identify virus-infected cells. To this end, replication-competent influenza A viruses (IAVs) expressing easily traceable fluorescent proteins have been recently developed. In contrast, similar approaches for IBV are mostly lacking. In this report, we describe the generation and characterization of replication-competent influenza B/Brisbane/60/2008 viruses expressing fluorescent mCherry or GFP fused to the C-terminal of the viral non-structural 1 (NS1) protein. Fluorescent-expressing IBVs display similar growth kinetics and plaque phenotype to wild-type IBV, while fluorescent protein expression allows for the easy identification of virus-infected cells. Without the need of secondary approaches to monitor viral infection, fluorescent-expressing IBVs represent an ideal approach to study the biology of IBV and an excellent platform for the rapid identification and characterization of antiviral therapeutics or neutralizing antibodies using high-throughput screening approaches. Lastly, fluorescent-expressing IBVs can be combined with the recently described reporter-expressing IAVs for the identification of novel therapeutics to combat these two important human respiratory pathogens. PMID:26590325

  11. Influenza: the virus and prophylaxis with inactivated influenza vaccine in "at risk" groups, including COPD patients.

    PubMed

    Hovden, Arnt-Ove; Cox, Rebecca Jane; Haaheim, Lars Reinhardt

    2007-01-01

    Influenza is a major respiratory pathogen, which exerts a huge human and economic toll on society. Influenza is a vaccine preventable disease, however, the vaccine strains must be annually updated due to the continuous antigenic changes in the virus. Inactivated influenza vaccines have been used for over 50 years and have an excellent safety record. Annual vaccination is therefore recommended for all individuals with serious medical conditions, like COPD, and protects the vaccinee against influenza illness and also against hospitalization and death. In COPD patients, influenza infection can lead to exacerbations resulting in reduced quality of life, hospitalization and death in the most severe cases. Although there is only limited literature on the use of influenza vaccination solely in COPD patients, there is clearly enough evidence to recommend annual vaccination in this group. This review will focus on influenza virus and prophylaxis with inactivated influenza vaccines in COPD patients and other "at risk" groups to reduce morbidity, save lives, and reduce health care costs. PMID:18229561

  12. The PB1 segment of an influenza A virus H1N1 2009pdm isolate enhances the replication efficiency of specific influenza vaccine strains in cell culture and embryonated eggs.

    PubMed

    Mostafa, Ahmed; Kanrai, Pumaree; Ziebuhr, John; Pleschka, Stephan

    2016-03-01

    Influenza vaccine strains (IVSs) contain the haemagglutinin (HA) and neuraminidase (NA) genome segments of relevant circulating strains in the genetic background of influenza A/PR/8/1934 virus (PR8). Previous work has shown that the nature of the PB1 segment may be a limiting factor for the efficient production of IVSs. Here, we showed that the PB1 segment (PB1Gi) from the 2009 pandemic influenza A virus (IAV) A/Giessen/06/2009 (Gi wt, H1N1pdm) may help to resolve (some of) these limitations. We produced a set of recombinant PR8-derived viruses that contained (i) the HA and NA segments from representative IAV strains (H3N2, H5N1, H7N9, H9N2); (ii) the PB1 segment from PR8 or Gi wt, respectively; and (iii) the remaining five genome segments from PR8. Viruses containing the PB1Gi segment, together with the heterologous HA/NA segments and five PR8 segments (5+2+1), replicated to higher titres compared with their 6+2 counterparts containing six PR8 segments and the equivalent heterologous HA/NA segments. Compared with PB1PR8-containing IVSs, viruses with the PB1Gi segment replicated to higher or similar titres in both cell culture and embryonated eggs, most profoundly IVSs of the H5N1 and H7N9 subtype, which are known to grow poorly in these systems. IVSs containing either the PB1Gi or the cognate PB1 segment of the respective specific HA/NA donor strain showed enhanced or similar virus replication levels. This study suggests that substitution of PB1PR8 with the PB1Gi segment may greatly improve the large-scale production of PR8-derived IVSs, especially of those known to replicate poorly in vitro. PMID:26743314

  13. Chitosan nanoparticle encapsulated hemagglutinin-split influenza virus mucosal vaccine.

    PubMed

    Sawaengsak, Chompoonuch; Mori, Yasuko; Yamanishi, Koichi; Mitrevej, Ampol; Sinchaipanid, Nuttanan

    2014-04-01

    Subunit/split influenza vaccines are less reactogenic compared with the whole virus vaccines. However, their immunogenicity is relatively low and thus required proper adjuvant and/or delivery vehicle for immunogenicity enhancement. Influenza vaccines administered intramuscularly induce minimum, if any, mucosal immunity at the respiratory mucosa which is the prime site of the infection. In this study, chitosan (CS) nanoparticles were prepared by ionic cross-linking of the CS with sodium tripolyphosphate (TPP) at the CS/TPP ratio of 1:0.6 using 2 h mixing time. The CS/TPP nanoparticles were used as delivery vehicle of an intranasal influenza vaccine made of hemagglutinin (HA)-split influenza virus product. Innocuousness, immunogenicity, and protective efficacy of the CS/TPP-HA vaccine were tested in influenza mouse model in comparison with the antigen alone vaccine. The CS/TPP-HA nanoparticles had required characteristics including nano-sizes, positive charges, and high antigen encapsulation efficiency. Mice that received two doses of the CS/TPP-HA vaccine intranasally showed no adverse symptoms indicating the vaccine innocuousness. The animals developed higher systemic and mucosal antibody responses than vaccine made of the HA-split influenza virus alone. The CS/TPP-HA vaccine could induce also a cell-mediated immune response shown as high numbers of IFN-γ-secreting cells in spleens while the HA vaccine alone could not. Besides, the CS nanoparticle encapsulated HA-split vaccine reduced markedly the influenza morbidity and also conferred 100% protective rate to the vaccinated mice against lethal influenza virus challenge. Overall results indicated that the CS nanoparticles invented in this study is an effective and safe delivery vehicle/adjuvant for the influenza vaccine. PMID:24343789

  14. Protection against divergent influenza H1N1 virus by a centralized influenza hemagglutinin.

    PubMed

    Weaver, Eric A; Rubrum, Adam M; Webby, Richard J; Barry, Michael A

    2011-01-01

    Influenza poses a persistent worldwide threat to the human population. As evidenced by the 2009 H1N1 pandemic, current vaccine technologies are unable to respond rapidly to this constantly diverging pathogen. We tested the utility of adenovirus (Ad) vaccines expressing centralized consensus influenza antigens. Ad vaccines were produced within 2 months and protected against influenza in mice within 3 days of vaccination. Ad vaccines were able to protect at doses as low as 10(7) virus particles/kg indicating that approximately 1,000 human doses could be rapidly generated from standard Ad preparations. To generate broadly cross-reactive immune responses, centralized consensus antigens were constructed against H1 influenza and against H1 through H5 influenza. Twenty full-length H1 HA sequences representing the main branches of the H1 HA phylogenetic tree were used to create a synthetic centralized gene, HA1-con. HA1-con minimizes the degree of sequence dissimilarity between the vaccine and existing circulating viruses. The centralized H1 gene, HA1-con, induced stronger immune responses and better protection against mismatched virus challenges as compared to two wildtype H1 genes. HA1-con protected against three genetically diverse lethal influenza challenges. When mice were challenged with 1934 influenza A/PR/8/34, HA1-con protected 100% of mice while vaccine generated from 2009 A/TX/05/09 only protected 40%. Vaccination with 1934 A/PR/8/34 and 2009 A/TX/05/09 protected 60% and 20% against 1947 influenza A/FM/1/47, respectively, whereas 80% of mice vaccinated with HA1-con were protected. Notably, 80% of mice challenged with 2009 swine flu isolate A/California/4/09 were protected by HA1-con vaccination. These data show that HA1-con in Ad has potential as a rapid and universal vaccine for H1N1 influenza viruses. PMID:21464940

  15. Immunohistochemical staining of avian influenza viruses in tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immunohistochemical methods are commonly used for studying the pathogenesis of avian influenza virus by allowing the identification of sites of replication of the virus in infected tissues and the correlation with the histopathological changes observed. In this chapter, the materials and methods fo...

  16. DETECTION OF AVIAN INFLUENZA VIRUS USING AN INTERFEROMETRIC BIOSENSOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An optical interferometric waveguide immunoassay for direct and label-less detection of avian influenza virus is described. The assay response is based on index of refraction changes that occur upon binding of virus particles to antigen (hemagglutinin) specific antibodies on the waveguide surface. ...

  17. A brief introduction to influenza A virus in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Control of Influenza and Poliomyelitis with Killed Virus Vaccines

    ERIC Educational Resources Information Center

    Salk, Jonas; Salk, Darrell

    1977-01-01

    Discusses control of poliomyelitis and influenza by live and killed virus vaccines. Considered are the etiological agents, pathogenic mechanisms and epidemiology of each disease. Reviews recent scientific studies of the diseases. Recommends use of killed virus vaccines in controlling both diseases. (CS)

  19. Rapidly Expanding Range of Highly Pathogenic Avian Influenza Viruses

    PubMed Central

    Dusek, Robert J.; Spackman, Erica

    2015-01-01

    The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus’ propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions. PMID:26079209

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

    PubMed

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

    2015-10-01

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

  1. Immunohistochemical staining of avian influenza virus in tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immunohistochemical methods are commonly used for studying the pathogenesis of avian influenza (AI) virus by allowing the identification of sites of replication of the virus in infected tissues and the correlation with the histopathological changes observed. In this chapter, the materials and metho...

  2. Rapidly expanding range of highly pathogenic avian influenza viruses

    USGS Publications Warehouse

    Hall, Jeffrey S.; Dusek, Robert J.; Spackman, Erica

    2015-01-01

    The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus’ propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions.

  3. Inhibition of influenza virus uncoating by rimantadine hydrochloride.

    PubMed Central

    Koff, W C; Knight, V

    1979-01-01

    In freeze-thaw lysates of MDCK cells infected with 32P-labeled influenza virus A/WSN in the presence of added RNase, acid-precipitable radioactivity diminished to about 50% of initial values within 90 min after a 1-h virus adsorption period. A similar preparation containing rimantadine at a concentration of 50 micrograms/ml exhibited only a 10% reduction in acid-precipitable radioactivity. These findings suggest that rimantadine interferes with uncoating of influenza virus in infected cells. PMID:501798

  4. Influenza and other respiratory viruses in three Central American countries

    PubMed Central

    Laguna‐Torres, Victor A.; Sánchez‐Largaespada, José F.; Lorenzana, Ivette; Forshey, Brett; Aguilar, Patricia; Jimenez, Mirna; Parrales, Eduardo; Rodriguez, Francisco; García, Josefina; Jimenez, Ileana; Rivera, Maribel; Perez, Juan; Sovero, Merly; Rios, Jane; Gamero, María E.; Halsey, Eric S.; Kochel, Tadeusz J.

    2010-01-01

    Please cite this paper as: Laguna‐Torres et al. (2011) Influenza and other respiratory viruses in three Central American countries. Influenza and Other Respiratory Viruses 5(2), 123–134. Background  Despite the disease burden imposed by respiratory diseases on children in Central America, there is a paucity of data describing the etiologic agents of the disease. Aims  To analyze viral etiologic agents associated with influenza‐like illness (ILI) in participants reporting to one outpatient health center, one pediatric hospital, and three general hospitals in El Salvador, Honduras, and Nicaragua Material & Methods  Between August 2006 and April 2009, pharyngeal swabs were collected from outpatients and inpatients. Patient specimens were inoculated onto cultured cell monolayers, and viral antigens were detected by indirect and direct immunofluorescence staining. Results  A total of 1,756 patients were enrolled, of whom 1,195 (68.3%) were under the age of 5; and 183 (10.4%) required hospitalization. One or more viral agents were identified in 434 (24.7%) cases, of which 17 (3.9%) were dual infections. The most common viruses isolated were influenza A virus (130; 7.4% of cases), respiratory syncytial virus (122; 6.9%), adenoviruses (63; 3.6%), parainfluenza viruses (57; 3.2%), influenza B virus (47; 2.7% of cases), and herpes simplex virus 1 (22; 1.3%). In addition, human metapneumovirus and enteroviruses (coxsackie and echovirus) were isolated from patient specimens. Discussion  When compared to the rest of the population, viruses were isolated from a significantly higher percentage of patients age 5 or younger. The prevalence of influenza A virus or influenza B virus infections was similar between the younger and older age groups. RSV was the most commonly detected pathogen in infants age 5 and younger and was significantly associated with pneumonia (p < 0.0001) and hospitalization (p < 0.0001). Conclusion  Genetic analysis of influenza

  5. Swine Influenza Viruses: a North American Perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza is a zoonotic viral disease that represents a health and economic threat to both humans and animals worldwide. Swine influenza was first recognized clinically in pigs in the Midwestern U.S. in 1918, coinciding with the human influenza pandemic known as the Spanish flu. Since that time swin...

  6. Antibody Recognition of a Highly Conserved Influenza Virus Epitope

    SciTech Connect

    Ekiert, Damian C.; Bhabha, Gira; Elsliger, Marc-André; Friesen, Robert H.E.; Jongeneelen, Mandy; Throsby, Mark; Goudsmit, Jaap; Wilson, Ian A.; Scripps; Crucell

    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 a 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.

  7. Influenza virus binds its host cell using multiple dynamic interactions

    PubMed Central

    Sieben, Christian; Kappel, Christian; Zhu, Rong; Wozniak, Anna; Rankl, Christian; Hinterdorfer, Peter; Grubmüller, Helmut; Herrmann, Andreas

    2012-01-01

    Influenza virus belongs to a wide range of enveloped viruses. The major spike protein hemagglutinin binds sialic acid residues of glycoproteins and glycolipids with dissociation constants in the millimolar range [Sauter NK, et al. (1992) Biochemistry 31:9609–9621], indicating a multivalent binding mode. Here, we characterized the attachment of influenza virus to host cell receptors using three independent approaches. Optical tweezers and atomic force microscopy-based single-molecule force spectroscopy revealed very low interaction forces. Further, the observation of sequential unbinding events strongly suggests a multivalent binding mode between virus and cell membrane. Molecular dynamics simulations reveal a variety of unbinding pathways that indicate a highly dynamic interaction between HA and its receptor, allowing rationalization of influenza virus–cell binding quantitatively at the molecular level. PMID:22869709

  8. Chiropteran influenza viruses: flu from bats or a relic from the past?

    PubMed

    Brunotte, Linda; Beer, Martin; Horie, Masayuki; Schwemmle, Martin

    2016-02-01

    The identification of influenza A-like genomic sequences in bats suggests the existence of distinct lineages of chiropteran influenza viruses in South and Central America. These viruses share similarities with conventional influenza A viruses but lack the canonical receptor-binding property and neuraminidase function. The inability to isolate infectious bat influenza viruses impeded further studies, however, reverse genetic analysis provided new insights into the molecular biology of these viruses. In this review, we highlight the recent developments in the field of the newly discovered bat-derived influenza A-like viruses. We also discuss whether bats are a neglected natural reservoir of influenza viruses, the risk associated with bat influenza viruses for humans and whether these viruses originate from the pool of avian IAV or vice versa. PMID:26947779

  9. Influenza A(H1N1)pdm09 virus infection in giant pandas, China.

    PubMed

    Li, Desheng; Zhu, Ling; Cui, Hengmin; Ling, Shanshan; Fan, Shengtao; Yu, Zhijun; Zhou, Yuancheng; Wang, Tiecheng; Qian, Jun; Xia, Xianzhu; Xu, Zhiwen; Gao, Yuwei; Wang, Chengdong

    2014-03-01

    We confirmed infection with influenza A(H1N1)pdm09 in giant pandas in China during 2009 by using virus isolation and serologic analysis methods. This finding extends the host range of influenza viruses and indicates a need for increased surveillance for and control of influenza viruses among giant pandas. PMID:24565026

  10. The role of swine in the generation of novel influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ecology of influenza A viruses is very complicated involving multiple host species and viral genes. Avian species have variable susceptibility to influenza A viruses and they are the reservoir for this group of pathogens. Occasionally, influenza A viruses are transmitted to mammals from avian ...

  11. Viral Reassortment and Transmission after Coinfection of Pigs with two Swine Influenza Viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Influenza A viruses of subtypes H3N2, H1N1 and H1N2 are circulating in U.S. swine. Because influenza A virus contains 8 RNA segments, genetic reassortment can take place when 2 or more influenza viruses infect the same cell. We studied the reassortment potential and transmissibility of swine influen...

  12. Influenza virus-like particles produced by transient expression in Nicotiana benthamiana induce a protective immune response against a lethal viral challenge in mice.

    PubMed

    D'Aoust, Marc-André; Lavoie, Pierre-Olivier; Couture, Manon M-J; Trépanier, Sonia; Guay, Jean-Martin; Dargis, Michèle; Mongrand, Sébastien; Landry, Nathalie; Ward, Brian J; Vézina, Louis-P

    2008-12-01

    A strain-specific vaccine represents the best possible response to the threat of an influenza pandemic. Rapid delivery of such a vaccine to the world's population before the peak of the first infection wave seems to be an unattainable goal with the current influenza vaccine manufacturing capacity. Plant-based transient expression is one of the few production systems that can meet the anticipated surge requirement. To assess the capability of plant agroinfiltration to produce an influenza vaccine, we expressed haemagglutinin (HA) from strains A/Indonesia/5/05 (H5N1) and A/New Caledonia/20/99 (H1N1) by agroinfiltration of Nicotiana benthamiana plants. Size distribution analysis of protein content in infiltrated leaves revealed that HA was predominantly assembled into high-molecular-weight structures. H5-containing structures were purified and examination by transmission electron microscopy confirmed virus-like particle (VLP) assembly. High-performance thin layer chromatography analysis of VLP lipid composition highlighted polar and neutral lipid contents comparable with those of purified plasma membranes from tobacco plants. Electron microscopy of VLP-producing cells in N. benthamiana leaves confirmed that VLPs accumulated in apoplastic indentations of the plasma membrane. Finally, immunization of mice with two doses of as little as 0.1 microg of purified influenza H5-VLPs triggered a strong immune response against the homologous virus, whereas two doses of 0.5 microg of H5-VLPs conferred complete protection against a lethal challenge with the heterologous A/Vietnam/1194/04 (H5N1) strain. These results show, for the first time, that plants are capable of producing enveloped influenza VLPs budding from the plasma membrane; such VLPs represent very promising candidates for vaccination against influenza pandemic strains. PMID:19076615

  13. Recombinant adenovirus expressing the haemagglutinin of Peste des petits ruminants virus (PPRV) protects goats against challenge with pathogenic virus; a DIVA vaccine for PPR.

    PubMed

    Herbert, Rebecca; Baron, Jana; Batten, Carrie; Baron, Michael; Taylor, Geraldine

    2014-01-01

    Peste des petits ruminants virus (PPRV) is a morbillivirus that can cause severe disease in sheep and goats, characterised by pyrexia, pneumo-enteritis, and gastritis. The socio-economic burden of the disease is increasing in underdeveloped countries, with poor livestock keepers being affected the most. Current vaccines consist of cell-culture attenuated strains of PPRV, which induce a similar antibody profile to that induced by natural infection. Generation of a vaccine that enables differentiation of infected from vaccinated animals (DIVA) would benefit PPR control and eradication programmes, particularly in the later stages of an eradication campaign and for countries where the disease is not endemic. In order to create a vaccine that would enable infected animals to be distinguished from vaccinated ones (DIVA vaccine), we have evaluated the immunogenicity of recombinant fowlpox (FP) and replication-defective recombinant human adenovirus 5 (Ad), expressing PPRV F and H proteins, in goats. The Ad constructs induced higher levels of virus-specific and neutralising antibodies, and primed greater numbers of CD8+ T cells than the FP-vectored vaccines. Importantly, a single dose of Ad-H, with or without the addition of Ad expressing ovine granulocyte macrophage colony-stimulating factor and/or ovine interleukin-2, not only induced strong antibody and cell-mediated immunity but also completely protected goats against challenge with virulent PPRV, 4 months after vaccination. Replication-defective Ad-H therefore offers the possibility of an effective DIVA vaccine. PMID:24568545

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. Reduction of Influenza Virus Envelope's Fusogenicity by Viral Fusion Inhibitors.

    PubMed

    Rowse, Michael; Qiu, Shihong; Tsao, Jun; Yamauchi, Yohei; Wang, Guoxin; Luo, Ming

    2016-01-01

    During cell entry of an enveloped virus, the viral membrane must be fused with the cellular membrane. The virus envelope has a unique structure consisting of viral proteins and a virus-specific lipid composition, whereas the host membrane has its own structure with host membrane proteins. Compound 136 was previously found to bind in close proximity to the viral envelope and inhibit influenza virus entry. We showed here that the 136-treated influenza virus still caused hemolysis. When liposomes were used as the target membrane for 136-treated viruses, aberrant fusion occurred; few liposomes fused per virion, and glycoproteins were not distributed evenly across fusion complexes. Additionally, large fusion aggregates did not form, and in some instances, neck-like structures were found. Based on previous results and hemolysis, fusion inhibition by 136 occurs post-scission but prior to lipid mixing. PMID:27622947

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

    PubMed

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

    2015-08-01

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

  18. 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

  19. Analysis of in vivo dynamics of influenza virus infection in mice using a GFP reporter virus

    PubMed Central

    Manicassamy, Balaji; Manicassamy, Santhakumar; Belicha-Villanueva, Alan; Pisanelli, Giuseppe; Pulendran, Bali; García-Sastre, Adolfo

    2010-01-01

    Influenza A virus is being extensively studied because of its major impact on human and animal health. However, the dynamics of influenza virus infection and the cell types infected in vivo are poorly understood. These characteristics are challenging to determine, partly because there is no efficient replication-competent virus expressing an easily traceable reporter gene. Here, we report the generation of a recombinant influenza virus carrying a GFP reporter gene in the NS segment (NS1-GFP virus). Although attenuated when compared with wild-type virus, the NS1-GFP virus replicates efficiently in murine lungs and shows pathogenicity in mice. Using whole-organ imaging and flow cytometry, we have tracked the dynamics of influenza virus infection progression in mice. Imaging of murine lungs shows that infection starts in the respiratory tract in areas close to large conducting airways and later spreads to deeper sections of the lungs. In addition to epithelial cells, we found GFP-positive antigen-presenting cells, such as CD11b+CD11c−, CD11b−CD11c+, and CD11b+CD11c+, as early as 24 h after intranasal infection. In addition, a significant proportion of NK and B cells were GFP positive, suggesting active infection of these cells. We next tested the effects of the influenza virus inhibitors oseltamivir and amantadine on the kinetics of in vivo infection progression. Treatment with oseltamivir dramatically reduced influenza infection in all cell types, whereas, surprisingly, amantadine treatment more efficiently blocked infection in B and NK cells. Our results demonstrate high levels of immune cells harboring influenza virus antigen during viral infection and cell-type–specific effects upon treatment with antiviral agents, opening additional avenues of research in the influenza virus field. PMID:20534532

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

    PubMed

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

    2015-10-01

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

  1. Isolation of an influenza A virus of unusual subtype (H1N7) from pigs in England, and the subsequent experimental transmission from pig to pig.

    PubMed

    Brown, I H; Alexander, D J; Chakraverty, P; Harris, P A; Manvell, R J

    1994-03-01

    A novel H1N7 influenza virus (A/swine/Eng/191973/92) was isolated from nasal swabs collected from two pigs on a farm where there had been recent clinical disease due to infection with an H1N1 virus (A/swine/Eng/195852/92). Antigenically, the haemagglutinin (HA) of the H1N7 virus was related most closely to the HA of A/USSR/90/77, whilst the neuraminidase (NA) appeared to be related most closely to the NA of A/equine/Prague/1/56 (H7N7). Pigs infected experimentally with A/swine/Eng/191973/92 developed mild clinical signs, excreted virus into the nasal passages for up to nine days after infection, appeared normal at necropsy, transmitted the virus to sentinel pigs, but seven out of eight pigs failed to seroconvert. These findings suggest that the H1N7 virus has a low pathogenicity for pigs, resulting in limited virus multiplication which is insufficient to stimulate a detectable primary humoral immune response. PMID:8203118

  2. Avian Influenza A Viruses: Evolution and Zoonotic Infection.

    PubMed

    Kim, Se Mi; Kim, Young-Il; Pascua, Philippe Noriel Q; Choi, Young Ki

    2016-08-01

    Although efficient human-to-human transmission of avian influenza virus has yet to be seen, in the past two decades avian-to-human transmission of influenza A viruses has been reported. Influenza A/H5N1, in particular, has repeatedly caused human infections associated with high mortality, and since 1998 the virus has evolved into many clades of variants with significant antigenic diversity. In 2013, three (A/H7N9, A/H6N1, and A/H10N8) novel avian influenza viruses (AIVs) breached the animal-human host species barrier in Asia. In humans, roughly 35% of A/H7N9-infected patients succumbed to the zoonotic infection, and two of three A/H10N8 human infections were also lethal; however, neither of these viruses cause influenza-like symptoms in poultry. While most of these cases were associated with direct contact with infected poultry, some involved sustained human-to-human transmission. Thus, these events elicited concern regarding potential AIV pandemics. This article reviews the human incursions associated with AIV variants and the potential role of pigs as an intermediate host that may hasten AIV evolution. In addition, we discuss the known influenza A virus virulence and transmission factors and their evaluation in animal models. With the growing number of human AIV infections, constant vigilance for the emergence of novel viruses is of utmost importance. In addition, careful characterization and pathobiological assessment of these novel variants will help to identify strains of particular concern for future pandemics. PMID:27486732

  3. Cryptoporus volvatus Extract Inhibits Influenza Virus Replication In Vitro and In Vivo

    PubMed Central

    Si, Jianyong; Liu, Jinhua; Sun, Guibo; Sun, Xiaobo; Cao, Li

    2014-01-01

    Influenza virus is the cause of significant morbidity and mortality, posing a serious health threat worldwide. Here, we evaluated the antiviral activities of Cryptoporus volvatus extract on influenza virus infection. Our results demonstrated that the Cryptoporus volvatus extract inhibited different influenza virus strain replication in MDCK cells. Time course analysis indicated that the extract exerted its inhibition at earlier and late stages in the replication cycle of influenza virus. Subsequently, we confirmed that the extract suppressed virus internalization into and released from cells. Moreover, the extract significantly reduced H1N1/09 influenza virus load in lungs and dramatically decreased lung lesions in mice. And most importantly, the extract protected mice from lethal challenge with H1N1/09 influenza virus. Our results suggest that the Cryptoporus volvatus extract could be a potential candidate for the development of a new anti-influenza virus therapy. PMID:25437846

  4. RIG-I Signaling Is Essential for Influenza B Virus-Induced Rapid Interferon Gene Expression

    PubMed Central

    Österlund, Pamela; Westenius, Veera; Latvala, Sinikka; Diamond, Michael S.; Gale, Michael; Julkunen, Ilkka

    2015-01-01

    ABSTRACT Influenza B virus causes annual epidemics and, along with influenza A virus, accounts for substantial disease and economic burden throughout the world. Influenza B virus infects only humans and some marine mammals and is not responsible for pandemics, possibly due to a very low frequency of reassortment and a lower evolutionary rate than that of influenza A virus. Influenza B virus has been less studied than influenza A virus, and thus, a comparison of influenza A and B virus infection mechanisms may provide new insight into virus-host interactions. Here we analyzed the early events in influenza B virus infection and interferon (IFN) gene expression in human monocyte-derived macrophages and dendritic cells. We show that influenza B virus induces IFN regulatory factor 3 (IRF3) activation and IFN-λ1 gene expression with faster kinetics than does influenza A virus, without a requirement for viral protein synthesis or replication. Influenza B virus-induced activation of IRF3 required the fusion of viral and endosomal membranes, and nuclear accumulation of IRF3 and viral NP occurred concurrently. In comparison, immediate early IRF3 activation was not observed in influenza A virus-infected macrophages. Experiments with RIG-I-, MDA5-, and RIG-I/MDA5-deficient mouse fibroblasts showed that RIG-I is the critical pattern recognition receptor needed for the influenza B virus-induced activation of IRF3. Our results show that innate immune mechanisms are activated immediately after influenza B virus entry through the endocytic pathway, whereas influenza A virus avoids early IRF3 activation and IFN gene induction. IMPORTANCE Recently, a great deal of interest has been paid to identifying the ligands for RIG-I under conditions of natural infection, as many previous studies have been based on transfection of cells with different types of viral or synthetic RNA structures. We shed light on this question by analyzing the earliest step in innate immune recognition of

  5. Development and Pre-Clinical Evaluation of Two LAIV Strains against Potentially Pandemic H2N2 Influenza Virus

    PubMed Central

    Smolonogina, Tatiana; Rekstin, Andrey; van Amerongen, Geert; van Dijken, Harry; Mouthaan, Justin; Roholl, Paul; Kuznetsova, Victoria; Doroshenko, Elena; Tsvetnitsky, Vadim; Rudenko, Larisa

    2014-01-01

    H2N2 Influenza A caused the Asian flu pandemic in 1957, circulated for more than 10 years and disappeared from the human population after 1968. Given that people born after 1968 are naïve to H2N2, that the virus still circulates in wild birds and that this influenza subtype has a proven pandemic track record, H2N2 is regarded as a potential pandemic threat. To prepare for an H2N2 pandemic, here we developed and tested in mice and ferrets two live attenuated influenza vaccines based on the haemagglutinins of the two different H2N2 lineages that circulated at the end of the cycle, using the well characterized A/Leningrad/134/17/57 (H2N2) master donor virus as the backbone. The vaccine strains containing the HA and NA of A/California/1/66 (clade 1) or A/Tokyo/3/67 (clade 2) showed a temperature sensitive and cold adapted phenotype and a reduced reproduction that was limited to the respiratory tract of mice, suggesting that the vaccines may be safe for use in humans. Both vaccine strains induced haemagglutination inhibition titers in mice. Vaccination abolished virus replication in the nose and lung and protected mice from weight loss after homologous and heterologous challenge with the respective donor wild type strains. In ferrets, the live attenuated vaccines induced high virus neutralizing, haemagglutination and neuraminidase inhibition titers, however; the vaccine based on the A/California/1/66 wt virus induced higher homologous and better cross-reactive antibody responses than the A/Tokyo/3/67 based vaccine. In line with this observation, was the higher virus reduction observed in the throat and nose of ferrets vaccinated with this vaccine after challenge with either of the wild type donor viruses. Moreover, both vaccines clearly reduced the infection-induced rhinitis observed in placebo-vaccinated ferrets. The results favor the vaccine based on the A/California/1/66 isolate, which will be evaluated in a clinical study. PMID:25058039

  6. Animal Models for Influenza Viruses: Implications for Universal Vaccine Development

    PubMed Central

    Margine, Irina; Krammer, Florian

    2014-01-01

    Influenza virus infections are a significant cause of morbidity and mortality in the human population. Depending on the virulence of the influenza virus strain, as well as the immunological status of the infected individual, the severity of the respiratory disease may range from sub-clinical or mild symptoms to severe pneumonia that can sometimes lead to death. Vaccines remain the primary public health measure in reducing the influenza burden. Though the first influenza vaccine preparation was licensed more than 60 years ago, current research efforts seek to develop novel vaccination strategies with improved immunogenicity, effectiveness, and breadth of protection. Animal models of influenza have been essential in facilitating studies aimed at understanding viral factors that affect pathogenesis and contribute to disease or transmission. Among others, mice, ferrets, pigs, and nonhuman primates have been used to study influenza virus infection in vivo, as well as to do pre-clinical testing of novel vaccine approaches. Here we discuss and compare the unique advantages and limitations of each model. PMID:25436508

  7. Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross‐reactive immunity in ferrets against infection with viruses drifted for decades

    PubMed Central

    Bragstad, Karoline; Martel, Cyril J.; Thomsen, Joakim S.; Jensen, Kim L.; Nielsen, Lars P.; Aasted, Bent; Fomsgaard, Anders

    2010-01-01

    Please cite this paper as: Bragstad et al. (2010) Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross‐reactive immunity in ferrets against infection with viruses drifted for decades. Influenza and Other Respiratory Viruses 5(1), 13–23. Background  Alternative influenza vaccines and vaccine production forms are needed as the conventional protein vaccines do not induce broad cross‐reactivity against drifted strains. Furthermore, fast vaccine production is especially important in a pandemic situation, and broader vaccine reactivity would diminish the need for frequent change in the vaccine formulations. Objective  In this study, we compared the ability of pandemic influenza DNA vaccines to induce immunity against distantly related strains within a subtype with the immunity induced by conventional trivalent protein vaccines against homologous virus challenge. Methods  Ferrets were immunised by particle‐mediated epidermal delivery (gene gun) with DNA vaccines based on the haemagglutinin (HA) and neuraminidase (NA) and/or the matrix (M) and nucleoprotein genes of the 1918 H1N1 Spanish influenza pandemic virus or the 1968 H3N2 Hong Kong influenza pandemic virus. The animals were challenged with contemporary H1N1 or H3N2 viruses. Results  We demonstrated that DNA vaccines encoding proteins of the original 1918 H1N1 pandemic virus induced protective cross‐reactive immune responses in ferrets against infection with a 1947 H1N1 virus and a recent 1999 H1N1 virus. Similarly, a DNA vaccine, based on the HA and NA of the 1968 H3N2 pandemic virus, induced cross‐reactive immune responses against a recent 2005 H3N2 virus challenge. Conclusions  DNA vaccines based on pandemic or recent seasonal influenza genes induced cross‐reactive immunity against contemporary virus challenge as good as or superior to contemporary conventional trivalent protein vaccines. This suggests a unique ability of influenza DNA to induce cross‐protective immunity

  8. Structural basis for the divergent evolution of influenza B virus hemagglutinin

    PubMed Central

    Ni, Fengyun; Kondrashkina, Elena; Wang, Qinghua

    2013-01-01

    Influenza A and B viruses are responsible for the severe morbidity and mortality worldwide in annual influenza epidemics. Currently circulating influenza B virus belongs to the B/Victoria or B/Yamagata lineage that was diverged from each other about 30–40 years ago. However, a mechanistic understanding of their divergent evolution is still lacking. Here we report the crystal structures of influenza B/Yamanashi/166/1998 hemagglutinin (HA) belonging to B/Yamagata lineage and its complex with the avian-like receptor analogue. Comparison of these structures with those of undiverged and diverged influenza B virus HAs, in conjunction with sequence analysis, reveals the molecular basis for the divergent evolution of influenza B virus HAs. Furthermore, HAs of diverged influenza B virus strains display much stronger molecular interactions with terminal sialic acid of bound receptors, which may allow for a different tissue tropism for current influenza B viruses, for which further investigation is required. PMID:24074573

  9. Variation and infectivity neutralization in influenza

    PubMed Central

    Knossow, Marcel; Skehel, John J

    2006-01-01

    Worldwide epidemics of influenza are caused by viruses that normally infect other species, particularly waterfowl, and that contain haemagglutinin membrane glycoproteins (HAs) to which the human population has no immunity. Anti-HA immunoglobulins neutralize influenza virus infectivity. In this review we outline structural differences that distinguish the HAs of the 16 antigenic subtypes (H1–16) found in viruses from avian species. We also describe structural changes in HA required for the effective transfer to humans of viruses containing three of them, H1, H2 and H3, in the 1918 (Spanish), the 1957 (Asian) and the 1968 (Hong Kong) pandemics, respectively. In addition, we consider changes that may be required before the current avian H5 viruses could pass from human to human. PMID:16925526

  10. Complexities in Ferret Influenza Virus Pathogenesis and Transmission Models.

    PubMed

    Belser, Jessica A; Eckert, Alissa M; Tumpey, Terrence M; Maines, Taronna R

    2016-09-01

    Ferrets are widely employed to study the pathogenicity, transmissibility, and tropism of influenza viruses. However, inherent variations in inoculation methods, sampling schemes, and experimental designs are often overlooked when contextualizing or aggregating data between laboratories, leading to potential confusion or misinterpretation of results. Here, we provide a comprehensive overview of parameters to consider when planning an experiment using ferrets, collecting data from the experiment, and placing results in context with previously performed studies. This review offers information that is of particular importance for researchers in the field who rely on ferret data but do not perform the experiments themselves. Furthermore, this review highlights the breadth of experimental designs and techniques currently available to study influenza viruses in this model, underscoring the wide heterogeneity of protocols currently used for ferret studies while demonstrating the wealth of information which can benefit risk assessments of emerging influenza viruses. PMID:27412880

  11. Virus-like particles as universal influenza vaccines

    PubMed Central

    Kang, Sang-Moo; Kim, Min-Chul; Compans, Richard W

    2012-01-01

    Current influenza vaccines are primarily targeted to induce immunity to the influenza virus strain-specific hemagglutinin antigen and are not effective in controlling outbreaks of new pandemic viruses. An approach for developing universal vaccines is to present highly conserved antigenic epitopes in an immunogenic conformation such as virus-like particles (VLPs) together with an adjuvant to enhance the vaccine immunogenicity. In this review, the authors focus on conserved antigenic targets and molecular adjuvants that were presented in VLPs. Conserved antigenic targets that include the hemagglutinin stalk domain, the external domain of influenza M2 and neuraminidase are discussed in addition to molecular adjuvants that are engineered to be incorporated into VLPs in a membrane-anchored form. PMID:23002980

  12. Hsp90 inhibitors reduce influenza virus replication in cell culture

    SciTech Connect

    Chase, Geoffrey; Deng, Tao; Fodor, Ervin; Leung, B.W.; Mayer, Daniel; Schwemmle, Martin Brownlee, George

    2008-08-01

    The viral RNA polymerase complex of influenza A virus consists of three subunits PB1, PB2 and PA. Recently, the cellular chaperone Hsp90 was shown to play a role in nuclear import and assembly of the trimeric polymerase complex by binding to PB1 and PB2. Here we show that Hsp90 inhibitors, geldanamycin or its derivative 17-AAG, delay the growth of influenza virus in cell culture resulting in a 1-2 log reduction in viral titre early in infection. We suggest that this is caused by the reduced half-life of PB1 and PB2 and inhibition of nuclear import of PB1 and PA which lead to reduction in viral RNP assembly. Hsp90 inhibitors may represent a new class of antiviral compounds against influenza viruses.

  13. Virus-like particles as universal influenza vaccines.

    PubMed

    Kang, Sang-Moo; Kim, Min-Chul; Compans, Richard W

    2012-08-01

    Current influenza vaccines are primarily targeted to induce immunity to the influenza virus strain-specific hemagglutinin antigen and are not effective in controlling outbreaks of new pandemic viruses. An approach for developing universal vaccines is to present highly conserved antigenic epitopes in an immunogenic conformation such as virus-like particles (VLPs) together with an adjuvant to enhance the vaccine immunogenicity. In this review, the authors focus on conserved antigenic targets and molecular adjuvants that were presented in VLPs. Conserved antigenic targets that include the hemagglutinin stalk domain, the external domain of influenza M2 and neuraminidase are discussed in addition to molecular adjuvants that are engineered to be incorporated into VLPs in a membrane-anchored form. PMID:23002980

  14. Replication-Competent Influenza B Reporter Viruses as Tools for Screening Antivirals and Antibodies

    PubMed Central

    Fulton, Benjamin O.; Palese, Peter

    2015-01-01

    Influenza B virus is a human pathogen responsible for significant health and economic burden. Research into this pathogen has been limited by the lack of reporter viruses. Here we describe the development of both a replication-competent fluorescent influenza B reporter virus and bioluminescent influenza B reporter virus. Furthermore, we demonstrate these reporter viruses can be used to quickly monitor viral growth and permit the rapid screening of antiviral compounds and neutralizing antibodies. PMID:26401044

  15. Intranasal immunization with influenza antigens conjugated with cholera toxin subunit B stimulates broad spectrum immunity against influenza viruses

    PubMed Central

    Li, Junwei; Arévalo, Maria T; Chen, Yanping; Posadas, Olivia; Smith, Jacob A; Zeng, Mingtao

    2014-01-01

    Frequent mutation of influenza viruses keep vaccinated and non-vaccinated populations vulnerable to new infections, causing serious burdens to public health and the economy. Vaccination with universal influenza vaccines would be the best way to effectively protect people from infection caused by mismatched or unforeseen influenza viruses. Presently, there is no FDA approved universal influenza vaccine. In this study, we expressed and purified a fusion protein comprising of influenza matrix 2 protein ectodomain peptides, a centralized influenza hemagglutinin stem region, and cholera toxin subunit B. Vaccination of BALB/c mice with this novel artificial antigen resulted in potent humoral immune responses, including induction of specific IgA and IgG, and broad protection against infection by multiple influenza viruses. Furthermore, our results demonstrated that when used as a mucosal antigen, cholera toxin subunit B improved antigen-stimulated T cell and memory B cell responses. PMID:24632749

  16. 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

  17. Evidence of influenza a virus RNA in siberian lake ice.

    PubMed

    Zhang, Gang; Shoham, Dany; Gilichinsky, David; Davydov, Sergei; Castello, John D; Rogers, Scott O

    2006-12-01

    Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest that influenza A virus, deposited as the birds begin their autumn migration, can be preserved in lake ice. As birds return in the spring, the ice melts, releasing the viruses. Therefore, temporal gene flow is facilitated between the viruses shed during the previous year and the viruses newly acquired by birds during winter months spent in the south. Above the Arctic Circle, the cycles of entrapment in the ice and release by melting can be variable in length, because some ice persists for several years, decades, or longer. This type of temporal gene flow might be a feature common to viruses that can survive entrapment in environmental ice and snow. PMID:17035314

  18. The Timeline of Influenza Virus Shedding in Children and Adults in a Household Transmission Study of Influenza in Managua, Nicaragua.

    PubMed

    Ng, Sophia; Lopez, Roger; Kuan, Guillermina; Gresh, Lionel; Balmaseda, Angel; Harris, Eva; Gordon, Aubree

    2016-05-01

    In a household transmission study in Nicaragua, children under 6 years old had a longer duration of presymptomatic influenza virus shedding than adults. The duration of postsymptomatic influenza virus shedding was longest in children 0-5 years old, followed by children 6-15 years of age and adults. PMID:26910589

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

    PubMed Central

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

    2011-01-01

    Please cite this paper as: Ngo et al. (2012) Isolation of novel triple‐reassortant swine H3N2 influenza viruses possessing the hemagglutinin and neuraminidase genes of a seasonal influenza virus in Vietnam in 2010. Influenza and Other Respiratory Viruses 6(1), 6–10. Surveillance of swine influenza viruses (SIVs) in 31 pig farms in northern and southern parts of Vietnam was conducted. Six H3N2 influenza A viruses were isolated from a pig farm in southern Vietnam. They were novel genetic reassortants between a triple–reassortant SIV and a human seasonal H3N2 virus. Their hemagglutinin and neuraminidase genes were derived from a human virus circulating around 2004–2006 and the remaining genes from a triple‐reassortant SIV that originated in North America. This is the first report describing the isolation of a novel triple‐reassortant SIV in Vietnam. PMID:21668659

  20. Identification of Newly Emerging Influenza Viruses by Surface-Enhanced Raman Spectroscopy.

    PubMed

    Lim, Jae-young; Nam, Jung-soo; Yang, Se-eun; Shin, Hyunku; Jang, Yoon-ha; Bae, Gyu-Un; Kang, Taewook; Lim, Kwang-il; Choi, Yeonho

    2015-12-01

    In this work, we demonstrate in situ virus identification based on surface-enhanced Raman scattering (SERS). We hypothesized that newly emerging influenza viruses possess surface proteins and lipids that can generate distinctive Raman signals. To test this hypothesis, SERS signals were measured from the surface of a noninfluenza virus, two different influenza viruses, and a genetically shuffled influenza virus. To ensure the safety for experimenters we constructed nonreplicating pseudotyped viruses that display main influenza virus surface components. Pseudotype with influenza virus components produced enhanced Raman peaks, on gold nanoparticles, that are easily distinguishable from those of pseudotype with a noninfluenza virus component, vesicular stomatitis virus G protein (VSVG). Furthermore, virus with the surface components of a newly emerging influenza strain, A/California/04/2009 (H1N1), generated Raman peaks different from those of viruses with components of the conventional laboratory-adapted influenza strain, A/WSN/33 (H1N1). Interestingly, the virus simultaneously displaying surface components of both influenza strains, a model mutant with genome reassortment, also produced a Raman signal pattern that is clearly distinguishable from those of each strain. This work highlights that SERS can provide a powerful label-free strategy to quickly identify newly emerging and potentially fatal influenza viruses. PMID:26528878

  1. Rapid preparation of mutated influenza hemagglutinins for influenza virus pandemic prevention.

    PubMed

    Nishioka, Ryosuke; Satomura, Atsushi; Yamada, Junki; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-03-01

    Influenza viruses have periodically caused pandemic due to frequent mutation of viral proteins. Influenza viruses have two major membrane glycoproteins: hemagglutinin (HA) and neuraminidase (NA). Hemagglutinin plays a crucial role in viral entry, while NA is involved in the process of a viral escape. In terms of developing antiviral drugs, HA is a more important target than NA in the prevention of pandemic, since HA is likely to change the host specificity of a virus by acquiring mutations, thereby to increase the risk of pandemic. To characterize mutated HA functions, current approaches require immobilization of purified HA on plastic wells and carriers. These troublesome methods make it difficult to respond to emerging mutations. In order to address this problem, a yeast cell surface engineering approach was investigated. Using this technology, human HAs derived from various H1N1 subtypes were successfully and rapidly displayed on the yeast cell surface. The yeast-displayed HAs exhibited similar abilities to native influenza virus HAs. Using this system, human HAs with 190E and 225G mutations were shown to exhibit altered recognition specificities from human to avian erythrocytes. This system furthermore allowed direct measurement of HA binding abilities without protein purification and immobilization. Coupled with the ease of genetic manipulation, this system allows the simple and comprehensive construction of mutant protein libraries on yeast cell surface, thereby contributing to influenza virus pandemic prevention. PMID:26797882

  2. Genetic and antigenic characterization of H1 influenza viruses from United States swine from 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine play an important role in the evolution of influenza A viruses. Prior to the introduction of the 2009 pandemic H1N1 virus from humans into pigs, four phylogenetic clusters of the hemagglutinin (HA) gene from H1 influenza viruses could be found in U.S. swine. Viruses from the classical H1N1 sw...

  3. Susceptibility of Swine to Low Pathogenic H5 and H7 Avian Influenza Viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: The emergence of the 2009 pandemic H1N1 influenza virus from swine origin viruses (1) reinforced the concern about transmission of animal influenza viruses to man. This follows the transmission of highly pathogenic H5N1 viruses from birds to people identified in the late 1990s and cont...

  4. Hemagglutinin Stalk Immunity Reduces Influenza Virus Replication and Transmission in Ferrets

    PubMed Central

    Nachbagauer, Raffael; Miller, Matthew S.; Hai, Rong; Ryder, Alex B.; Rose, John K.; Palese, Peter; García-Sastre, Adolfo

    2015-01-01

    We assessed whether influenza virus hemagglutinin stalk-based immunity protects ferrets against aerosol-transmitted H1N1 influenza virus infection. Immunization of ferrets by a universal influenza virus vaccine strategy based on viral vectors expressing chimeric hemagglutinin constructs induced stalk-specific antibody responses. Stalk-immunized ferrets were cohoused with H1N1-infected ferrets under conditions that permitted virus transmission. Hemagglutinin stalk-immunized ferrets had lower viral titers and delayed or no virus replication at all following natural exposure to influenza virus. PMID:26719251

  5. Hemagglutinin Stalk Immunity Reduces Influenza Virus Replication and Transmission in Ferrets.

    PubMed

    Nachbagauer, Raffael; Miller, Matthew S; Hai, Rong; Ryder, Alex B; Rose, John K; Palese, Peter; García-Sastre, Adolfo; Krammer, Florian; Albrecht, Randy A

    2016-03-01

    We assessed whether influenza virus hemagglutinin stalk-based immunity protects ferrets against aerosol-transmitted H1N1 influenza virus infection. Immunization of ferrets by a universal influenza virus vaccine strategy based on viral vectors expressing chimeric hemagglutinin constructs induced stalk-specific antibody responses. Stalk-immunized ferrets were cohoused with H1N1-infected ferrets under conditions that permitted virus transmission. Hemagglutinin stalk-immunized ferrets had lower viral titers and delayed or no virus replication at all following natural exposure to influenza virus. PMID:26719251

  6. Perspective of Use of Antiviral Peptides against Influenza Virus

    PubMed Central

    Skalickova, Sylvie; Heger, Zbynek; Krejcova, Ludmila; Pekarik, Vladimir; Bastl, Karel; Janda, Jozef; Kostolansky, Frantisek; Vareckova, Eva; Zitka, Ondrej; Adam, Vojtech; Kizek, Rene

    2015-01-01

    The threat of a worldwide influenza pandemic has greatly increased over the past decade with the emergence of highly virulent avian influenza strains. The increased frequency of drug-resistant influenza strains against currently available antiviral drugs requires urgent development of new strategies for antiviral therapy, too. The research in the field of therapeutic peptides began to develop extensively in the second half of the 20th century. Since then, the mechanisms of action for several peptides and their antiviral prospect received large attention due to the global threat posed by viruses. Here, we discussed the therapeutic properties of peptides used in influenza treatment. Peptides with antiviral activity against influenza can be divided into three main groups. First, entry blocker peptides such as a Flupep that interact with influenza hemagglutinin, block its binding to host cells and prevent viral fusion. Second, several peptides display virucidal activity, disrupting viral envelopes, e.g., Melittin. Finally, a third set of peptides interacts with the viral polymerase complex and act as viral replication inhibitors such as PB1 derived peptides. Here, we present a review of the current literature describing the antiviral activity, mechanism and future therapeutic potential of these influenza antiviral peptides. PMID:26492266

  7. Perspective of Use of Antiviral Peptides against Influenza Virus.

    PubMed

    Skalickova, Sylvie; Heger, Zbynek; Krejcova, Ludmila; Pekarik, Vladimir; Bastl, Karel; Janda, Jozef; Kostolansky, Frantisek; Vareckova, Eva; Zitka, Ondrej; Adam, Vojtech; Kizek, Rene

    2015-10-01

    The threat of a worldwide influenza pandemic has greatly increased over the past decade with the emergence of highly virulent avian influenza strains. The increased frequency of drug-resistant influenza strains against currently available antiviral drugs requires urgent development of new strategies for antiviral therapy, too. The research in the field of therapeutic peptides began to develop extensively in the second half of the 20(th) century. Since then, the mechanisms of action for several peptides and their antiviral prospect received large attention due to the global threat posed by viruses. Here, we discussed the therapeutic properties of peptides used in influenza treatment. Peptides with antiviral activity against influenza can be divided into three main groups. First, entry blocker peptides such as a Flupep that interact with influenza hemagglutinin, block its binding to host cells and prevent viral fusion. Second, several peptides display virucidal activity, disrupting viral envelopes, e.g., Melittin. Finally, a third set of peptides interacts with the viral polymerase complex and act as viral replication inhibitors such as PB1 derived peptides. Here, we present a review of the current literature describing the antiviral activity, mechanism and future therapeutic potential of these influenza antiviral peptides. PMID:26492266

  8. Heterogeneous and Dynamic Prevalence of Asymptomatic Influenza Virus Infections.

    PubMed

    Furuya-Kanamori, Luis; Cox, Mitchell; Milinovich, Gabriel J; Magalhaes, Ricardo J Soares; Mackay, Ian M; Yakob, Laith

    2016-06-01

    Influenza infection manifests in a wide spectrum of severity, including symptomless pathogen carriers. We conducted a systematic review and meta-analysis of 55 studies to elucidate the proportional representation of these asymptomatic infected persons. We observed extensive heterogeneity among these studies. The prevalence of asymptomatic carriage (total absence of symptoms) ranged from 5.2% to 35.5% and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) from 25.4% to 61.8%. Statistical analysis showed that the heterogeneity could not be explained by the type of influenza, the laboratory tests used to detect the virus, the year of the study, or the location of the study. Projections of infection spread and strategies for disease control require that we identify the proportional representation of these insidious spreaders early on in the emergence of new influenza subtypes or strains and track how this rate evolves over time and space. PMID:27191967

  9. Influenza A Virus Entry Inhibitors Targeting the Hemagglutinin

    PubMed Central

    Yang, Jie; Li, Minmin; Shen, Xintian; Liu, Shuwen

    2013-01-01

    Influenza A virus (IAV) has caused seasonal influenza epidemics and influenza pandemics, which resulted in serious threat to public health and socioeconomic impacts. Until now, only 5 drugs belong to two categories are used for prophylaxis and treatment of IAV infection. Hemagglutinin (HA), the envelope glycoprotein of IAV, plays a critical role in viral binding, fusion and entry. Therefore, HA is an attractive target for developing anti‑IAV drugs to block the entry step of IAV infection. Here we reviewed the recent progress in the study of conformational changes of HA during viral fusion process and the development of HA-based IAV entry inhibitors, which may provide a new choice for controlling future influenza pandemics. PMID:23340380

  10. Heterogeneous and Dynamic Prevalence of Asymptomatic Influenza Virus Infections

    PubMed Central

    Furuya-Kanamori, Luis; Cox, Mitchell; Milinovich, Gabriel J.; Magalhaes, Ricardo J. Soares; Mackay, Ian M.

    2016-01-01

    Influenza infection manifests in a wide spectrum of severity, including symptomless pathogen carriers. We conducted a systematic review and meta-analysis of 55 studies to elucidate the proportional representation of these asymptomatic infected persons. We observed extensive heterogeneity among these studies. The prevalence of asymptomatic carriage (total absence of symptoms) ranged from 5.2% to 35.5% and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) from 25.4% to 61.8%. Statistical analysis showed that the heterogeneity could not be explained by the type of influenza, the laboratory tests used to detect the virus, the year of the study, or the location of the study. Projections of infection spread and strategies for disease control require that we identify the proportional representation of these insidious spreaders early on in the emergence of new influenza subtypes or strains and track how this rate evolves over time and space. PMID:27191967

  11. Continuing Threat of Influenza (H5N1) Virus Circulation in Egypt

    PubMed Central

    El-Shesheny, Rabeh; Kutkat, Mohamed A.; Kandeil, Ahmed M.; Mostafa, Ahmed; Ducatez, Mariette F.; McKenzie, Pamela P.; Govorkova, Elena A.; Nasraa, Mohamed H.; Webster, Robert G.; Webby, Richard J.; Ali, Mohamed A.

    2011-01-01

    Reservoirs for the continuing influenza (H5N1) outbreaks in Egypt are ill-defined. Through active surveillance, we detected highly pathogenic influenza subtype H5 viruses in all poultry sectors; incidence was 5%. No other subtypes were found. Continued circulation of influenza (H5N1) viruses in various regions and poultry sectors perpetuates human exposure in Egypt. PMID:22172626

  12. 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

  13. Porcine macrophage Cdelta2+ and Cdelta2- cell lines support influenza virus infection and replication and Cdelta2+ cells mount innate immune responses to influenza virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Respiratory epithelial cells are the first cells which are infected with influenza virus and these cells play a major role in influenza pathogenesis. However, many studies have shown that alveolar macrophages also play a very important role in the pathogenesis and immunity to influenza infection. Un...

  14. 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

  15. A comprehensive map of the influenza A virus replication cycle

    PubMed Central

    2013-01-01

    Background Influenza is a common infectious disease caused by influenza viruses. Annual epidemics cause severe illnesses, deaths, and economic loss around the world. To better defend against influenza viral infection, it is essential to understand its mechanisms and associated host responses. Many studies have been conducted to elucidate these mechanisms, however, the overall picture remains incompletely understood. A systematic understanding of influenza viral infection in host cells is needed to facilitate the identification of influential host response mechanisms and potential drug targets. Description We constructed a comprehensive map of the influenza A virus (‘IAV’) life cycle (‘FluMap’) by undertaking a literature-based, manual curation approach. Based on information obtained from publicly available pathway databases, updated with literature-based information and input from expert virologists and immunologists, FluMap is currently composed of 960 factors (i.e., proteins, mRNAs etc.) and 456 reactions, and is annotated with ~500 papers and curation comments. In addition to detailing the type of molecular interactions, isolate/strain specific data are also available. The FluMap was built with the pathway editor CellDesigner in standard SBML (Systems Biology Markup Language) format and visualized as an SBGN (Systems Biology Graphical Notation) diagram. It is also available as a web service (online map) based on the iPathways+ system to enable community discussion by influenza researchers. We also demonstrate computational network analyses to identify targets using the FluMap. Conclusion The FluMap is a comprehensive pathway map that can serve as a graphically presented knowledge-base and as a platform to analyze functional interactions between IAV and host factors. Publicly available webtools will allow continuous updating to ensure the most reliable representation of the host-virus interaction network. The FluMap is available at http://www.influenza

  16. Influenza A Virus Infection, Innate Immunity, and Childhood

    PubMed Central

    Coates, Bria M.; Staricha, Kelly L.; Wiese, Kristin M.; Ridge, Karen M.

    2016-01-01

    Infection with influenza A virus is responsible for considerable morbidity and mortality in children worldwide. While it is apparent that adequate activation of the innate immune system is essential for pathogen clearance and host survival, an excessive inflammatory response to infection is detrimental to the young host. A review of the literature indicates that innate immune responses change throughout childhood. Whether these changes are genetically programmed or triggered by environmental cues is unknown. The objectives of this review are to summarize the role of innate immunity in influenza A virus infection in the young child and to highlight possible differences between children and adults that may make children more susceptible to severe influenza A infection. A better understanding of age-related differences in innate immune signaling will be essential to improve care for this high-risk population. PMID:26237589

  17. Serologic evidence of exposure of raptors to influenza A virus.

    PubMed

    Redig, Patrick T; Goyal, Sagar M

    2012-06-01

    Serum or plasma samples from raptors that prey or scavenge upon aquatic birds were tested by a commercially available blocking enzyme-linked immunosorbent assay for the evidence of antibodies to influenza A virus. Samples were taken from birds (n = 616) admitted to two rehabilitation centers in the United States. In addition, samples from 472 migrating peregrine falcons (Falco peregrinus) trapped on autumnal and vernal migrations for banding purposes were also tested. Only bald eagles were notably seropositive (22/406). One each of peregrine falcon, great horned owl (Bubo virginianus), and Cooper's hawk (Accipiter cooperi) from a total of 472, 81, and 100, respectively, were also positive. None of the turkey vultures (n = 21) or black vultures (n = 8) was positive. No clinical signs referable to avian influenza were seen in any bird at the time of capture. These data indicate that, among raptors, bald eagles do have exposure to influenza A viruses. PMID:22856203

  18. An Anti-Influenza Virus Antibody Inhibits Viral Infection by Reducing Nucleus Entry of Influenza Nucleoprotein

    PubMed Central

    Yoon, Aerin; Yi, Kye Sook; Chang, So Young; Kim, Sung Hwan; Song, Manki; Choi, Jung Ah; Bourgeois, Melissa; Hossain, M. Jaber; Chen, Li-Mei; Donis, Ruben O.; Kim, Hyori; Lee, Yujean; Hwang, Do Been; Min, Ji-Young; Chang, Shin Jae; Chung, Junho

    2015-01-01

    To date, four main mechanisms mediating inhibition of influenza infection by anti-hemagglutinin antibodies have been reported. Anti-globular-head-domain antibodies block either influenza virus receptor binding to the host cell or progeny virion release from the host cell. Anti-stem region antibodies hinder the membrane fusion process or induce antibody-dependent cytotoxicity to infected cells. In this study we identified a human monoclonal IgG1 antibody (CT302), which does not inhibit both the receptor binding and the membrane fusion process but efficiently reduced the nucleus entry of viral nucleoprotein suggesting a novel inhibition mechanism of viral infection by antibody. This antibody binds to the subtype-H3 hemagglutinin globular head domain of group-2 influenza viruses circulating throughout the population between 1997 and 2007. PMID:26512723

  19. An Anti-Influenza Virus Antibody Inhibits Viral Infection by Reducing Nucleus Entry of Influenza Nucleoprotein.

    PubMed

    Yoon, Aerin; Yi, Kye Sook; Chang, So Young; Kim, Sung Hwan; Song, Manki; Choi, Jung Ah; Bourgeois, Melissa; Hossain, M Jaber; Chen, Li-Mei; Donis, Ruben O; Kim, Hyori; Lee, Yujean; Hwang, Do Been; Min, Ji-Young; Chang, Shin Jae; Chung, Junho

    2015-01-01

    To date, four main mechanisms mediating inhibition of influenza infection by anti-hemagglutinin antibodies have been reported. Anti-globular-head-domain antibodies block either influenza virus receptor binding to the host cell or progeny virion release from the host cell. Anti-stem region antibodies hinder the membrane fusion process or induce antibody-dependent cytotoxicity to infected cells. In this study we identified a human monoclonal IgG1 antibody (CT302), which does not inhibit both the receptor binding and the membrane fusion process but efficiently reduced the nucleus entry of viral nucleoprotein suggesting a novel inhibition mechanism of viral infection by antibody. This antibody binds to the subtype-H3 hemagglutinin globular head domain of group-2 influenza viruses circulating throughout the population between 1997 and 2007. PMID:26512723

  20. Genetic characterization of highly pathogenic H5 influenza viruses from poultry in Taiwan, 2015.

    PubMed

    Huang, Pei-Yu; Lee, Chang-Chun David; Yip, Chun-Hung; Cheung, Chung-Lam; Yu, Guangchuang; Lam, Tommy Tsan-Yuk; Smith, David K; Zhu, Huachen; Guan, Yi

    2016-03-01

    Phylogenetic analysis of the highly pathogenic avian influenza (HPAI) H5 viruses causing recent outbreaks in Taiwan showed that they belonged to the Asian HPAI H5 lineage, clade 2.3.4.4 viruses, and were apparently introduced by migratory birds. These viruses reassorted with Eurasian influenza gene pool viruses and formed five genotypic variants. As Taiwan has a similar influenza ecosystem to southern China, the HPAI H5 lineage could become established and enzootic in the island. PMID:26690663

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Protective effect of dietary xylitol on influenza A virus infection.

    PubMed

    Yin, Sun Young; Kim, Hyoung Jin; Kim, Hong-Jin

    2014-01-01

    Xylitol has been used as a substitute for sugar to prevent cavity-causing bacteria, and most studies have focused on its benefits in dental care. Meanwhile, the constituents of red ginseng (RG) are known to be effective in ameliorating the symptoms of influenza virus infection when they are administered orally for 14 days. In this study, we investigated the effect of dietary xylitol on influenza A virus infection (H1N1). We designed regimens containing various fractions of RG (RGs: whole extract, water soluble fraction, saponin and polysaccharide) and xylitol, and combination of xylitol with the RG fractions. Mice received the various combinations orally for 5 days prior to lethal influenza A virus infection. Almost all the mice died post challenge when xylitol or RGs were administered separately. Survival was markedly enhanced when xylitol was administered along with RGs, pointing to a synergistic effect. The effect of xylitol plus RG fractions increased with increasing dose of xylitol. Moreover, dietary xylitol along with the RG water soluble fraction significantly reduced lung virus titers after infection. Therefore, we suggest that dietary xylitol is effective in ameliorating influenza-induced symptoms when it is administered with RG fractions, and this protective effect of xylitol should be considered in relation to other diseases. PMID:24392148

  3. Impact of host genes on resistance to avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    H5N1 high pathogenicity avian influenza (HPAI) virus has caused massive outbreaks of infection and disease in poultry, significant numbers of infections in wild aquatic birds and some infections in mammals and humans in Asia, Europe and Africa. The primary intervention strategy in poultry within de...

  4. [Purification of neuraminidase from influenza virus on an immunosorbent].

    PubMed

    Iakubov, L A; Savich, I M; Beklemishev, A B

    1984-10-01

    A procedure for isolation of neuraminidase from influenza virus using the nonionic detergent Triton x-100 was developed. To achieve further purification, the protein mixture was passed through a Sepharose column packed with immobilized antibodies against hemagglutinin. The neuraminidase preparation thus obtained fully retained its enzymatic and antigenic properties and during electrophoretic separation under denaturating conditions gave one protein band. PMID:6440594

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. Influenza A virus and secondary bacterial infection in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Highly pathogenic avian influenza virus among wild birds in Mongolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. Protective Effect of Dietary Xylitol on Influenza A Virus Infection

    PubMed Central

    Yin, Sun Young; Kim, Hyoung Jin; Kim, Hong-Jin

    2014-01-01

    Xylitol has been used as a substitute for sugar to prevent cavity-causing bacteria, and most studies have focused on its benefits in dental care. Meanwhile, the constituents of red ginseng (RG) are known to be effective in ameliorating the symptoms of influenza virus infection when they are administered orally for 14 days. In this study, we investigated the effect of dietary xylitol on influenza A virus infection (H1N1). We designed regimens containing various fractions of RG (RGs: whole extract, water soluble fraction, saponin and polysaccharide) and xylitol, and combination of xylitol with the RG fractions. Mice received the various combinations orally for 5 days prior to lethal influenza A virus infection. Almost all the mice died post challenge when xylitol or RGs were administered separately. Survival was markedly enhanced when xylitol was administered along with RGs, pointing to a synergistic effect. The effect of xylitol plus RG fractions increased with increasing dose of xylitol. Moreover, dietary xylitol along with the RG water soluble fraction significantly reduced lung virus titers after infection. Therefore, we suggest that dietary xylitol is effective in ameliorating influenza-induced symptoms when it is administered with RG fractions, and this protective effect of xylitol should be considered in relation to other diseases. PMID:24392148

  10. Canada geese and the epidemiology of avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canada geese (Branta canadensis) are numerous, highly visible, and widely distributed in both migratory and resident populations in North America; as a member of the Order Anseriformes, they are often suggested as a potential reservoir and source for avian influenza (AI) viruses. To further examine...

  11. Rapidly expanding range of highly pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent introduction of highly pathogenic avian influenza virus (HPAIV) H5N8 into Europe and North America poses significant risks to poultry industries and wildlife populations and warrants continued and heightened vigilance. First discovered in South Korean poultry and wild birds in early 2014...

  12. Oligonucleotide microchip for subtyping of influenza A virus

    PubMed Central

    Fesenko, Eugeny E.; Kireyev, Dmitry E.; Gryadunov, Dmitry A.; Mikhailovich, Vladimir M.; Grebennikova, Tatyana V.; L’vov, Dmitry K.; Zasedatelev, Alexander S.

    2007-01-01

    Background  Influenza A viruses are classified into subtypes depending on the antigenic properties of their two outer glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Sixteen subtypes of HA and nine of NA are known. Lately, the circulation of some subtypes (H7N7, H5N1) has been closely watched because of the epidemiological threat they present. Objectives  This study assesses the potential of using gel‐based microchip technology for fast and sensitive molecular subtyping of the influenza A virus. Methods  The method employs a microchip of 3D gel‐based elements containing immobilized probes. Segments of the HA and NA genes are amplified using multiplex RT‐PCR and then hybridized with the microchip. Results  The developed microchip was validated using a panel of 21 known reference strains of influenza virus. Selected strains represented different HA and NA subtypes derived from avian, swine and human hosts. The whole procedure takes 10 hours and enables one to identify 15 subtypes of HA and two subtypes of NA. Forty‐one clinical samples isolated during the poultry fall in Novosibirsk (Russia, 2005) were successfully identified using the proposed technique. The sensitivity and specificity of the method were 76% and 100%, respectively, compared with the ‘gold standard’ techniques (virus isolation with following characterization by immunoassay). Conclusions  We conclude that the method of subtyping using gel‐based microchips is a promising approach for fast detection and identification of influenza A, which may greatly improve its monitoring. PMID:19453417

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  14. 21 CFR 866.3330 - Influenza virus serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Influenza virus serological reagents. 866.3330 Section 866.3330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330...

  15. 21 CFR 866.3330 - Influenza virus serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Influenza virus serological reagents. 866.3330 Section 866.3330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330...

  16. 21 CFR 866.3330 - Influenza virus serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Influenza virus serological reagents. 866.3330 Section 866.3330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330...

  17. 21 CFR 866.3330 - Influenza virus serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Influenza virus serological reagents. 866.3330 Section 866.3330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330...

  18. 21 CFR 866.3330 - Influenza virus serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Influenza virus serological reagents. 866.3330 Section 866.3330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330...

  19. Avian influenza virus infection dynamics in shorebird hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using serial cross-sectional data from 2000-2008 and generalized linear models, we examined temporal trends of springtime avian influenza virus (AIV) prevalence and antibody prevalence in four Charadriiformes species at the Delaware Bay migratory stopover site. Prevalence of AIV in Ruddy Turnstones ...

  20. Reduced serologic sensitivity to influenza A virus illness among inactivated influenza vaccinees.

    PubMed

    Thompson, Mark G; Gaglani, Manjusha J; Naleway, Allison L; Dowell, Samuel H; Spencer, Sarah; Ball, Sarah; Levine, Min; Fry, Alicia

    2016-06-24

    We compared ≥4-fold increases in antibody titers by hemagglutination inhibition assay to RT-PCR results among 42 adults with PCR-confirmed influenza A virus illnesses. Serologic sensitivity was higher among unvaccinated (69%, 95% confidence interval [CI]=48-90%) than vaccinated healthcare personnel (38%, 95% CI=29-46%) in a 2010-11 prospective cohort. PMID:27195761

  1. Quantifying influenza virus diversity and transmission in humans

    PubMed Central

    Poon, Leo L.M.; Song, Timothy; Rosenfeld, Roni; Lin, Xudong; Rogers, Matthew B.; Zhou, Bin; Sebra, Robert; Halpin, Rebecca A.; Guan, Yi; Twaddle, Alan; DePasse, Jay V.; Stockwell, Timothy B.; Wentworth, David E.; Holmes, Edward C.; Greenbaum, Benjamin; Peiris, Joseph S.M.; Cowling, Benjamin J.; Ghedin, Elodie

    2016-01-01

    Influenza A virus is characterized by high genetic diversity.1–3 However, most of what we know about influenza evolution has come from consensus sequences sampled at the epidemiological scale4 that only represent the dominant virus lineage within each infected host. Less is known about the extent of intra-host virus diversity and what proportion is transmitted between individuals.5 To characterize those virus variants that achieve sustainable transmission in new hosts, we examined intra-host virus genetic diversity within household donor/recipient pairs from the first wave of the 2009 H1N1 pandemic when seasonal H3N2 was co-circulating. While the same variants were found in multiple members of the community, the relative frequencies of variants fluctuated, with patterns of genetic variation more similar within than between households. We estimated the effective population size of influenza A virus across donor/recipient pairs to be approximately 100–200 contributing members, which enabled the transmission of multiple lineages including antigenic variants. PMID:26727660

  2. Quantifying influenza virus diversity and transmission in humans.

    PubMed

    Poon, Leo L M; Song, Timothy; Rosenfeld, Roni; Lin, Xudong; Rogers, Matthew B; Zhou, Bin; Sebra, Robert; Halpin, Rebecca A; Guan, Yi; Twaddle, Alan; DePasse, Jay V; Stockwell, Timothy B; Wentworth, David E; Holmes, Edward C; Greenbaum, Benjamin; Peiris, Joseph S M; Cowling, Benjamin J; Ghedin, Elodie

    2016-02-01

    Influenza A virus is characterized by high genetic diversity. However, most of what is known about influenza evolution has come from consensus sequences sampled at the epidemiological scale that only represent the dominant virus lineage within each infected host. Less is known about the extent of within-host virus diversity and what proportion of this diversity is transmitted between individuals. To characterize virus variants that achieve sustainable transmission in new hosts, we examined within-host virus genetic diversity in household donor-recipient pairs from the first wave of the 2009 H1N1 pandemic when seasonal H3N2 was co-circulating. Although the same variants were found in multiple members of the community, the relative frequencies of variants fluctuated, with patterns of genetic variation more similar within than between households. We estimated the effective population size of influenza A virus across donor-recipient pairs to be approximately 100-200 contributing members, which enabled the transmission of multiple lineages, including antigenic variants. PMID:26727660

  3. Characterization of the glycoproteins of bat-derived influenza viruses.

    PubMed

    Maruyama, Junki; Nao, Naganori; Miyamoto, Hiroko; Maeda, Ken; Ogawa, Hirohito; Yoshida, Reiko; Igarashi, Manabu; Takada, Ayato

    2016-01-15

    Recently found bat-derived influenza viruses (BatIVs) have hemagglutinin (HA) and neuraminidase (NA) gene segments distinct from those of previously known influenza A viruses. However, pathogenicities of these BatIVs remain unknown since infectious virus strains have not been isolated yet. To gain insight into the biological properties of BatIVs, we generated vesicular stomatitis viruses (VSVs) pseudotyped with the BatIV HA and NA. We found that VSVs pseudotyped with BatIV HAs and NAs efficiently infected particular bat cell lines but not those derived from primates, and that proteolytic cleavage with a trypsin-like protease was necessary for HA-mediated virus entry. Treatment of the susceptible bat cells with some enzymes and inhibitors revealed that BatIV HAs might recognize some cellular glycoproteins as receptors rather than the sialic acids used for the other known influenza viruses. These data provide fundamental information on the mechanisms underlying the cellular entry and host restriction of BatIVs. PMID:26605499

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  6. Active NF-kappaB signalling is a prerequisite for influenza virus infection.

    PubMed

    Nimmerjahn, Falk; Dudziak, Diana; Dirmeier, Ulrike; Hobom, Gerd; Riedel, Alexander; Schlee, Martin; Staudt, Louis M; Rosenwald, Andreas; Behrends, Uta; Bornkamm, Georg W; Mautner, Josef

    2004-08-01

    Influenza virus still poses a major threat to human health. Despite widespread vaccination programmes and the development of drugs targeting essential viral proteins, the extremely high mutation rate of influenza virus still leads to the emergence of new pathogenic virus strains. Therefore, it has been suggested that cellular cofactors that are essential for influenza virus infection might be better targets for antiviral therapy. It has previously been reported that influenza virus efficiently infects Epstein-Barr virus-immortalized B cells, whereas Burkitt's lymphoma cells are virtually resistant to infection. Using this cellular system, it has been shown here that an active NF-kappaB signalling pathway is a general prerequisite for influenza virus infection of human cells. Cells with low NF-kappaB activity were resistant to influenza virus infection, but became susceptible upon activation of NF-kappaB. In addition, blocking of NF-kappaB activation severely impaired influenza virus infection of otherwise highly susceptible cells, including the human lung carcinoma cell lines A549 and U1752 and primary human cells. On the other hand, infection with vaccinia virus was not dependent on an active NF-kappaB signalling pathway, demonstrating the specificity of this pathway for influenza virus infection. These results might be of major importance for both the development of new antiviral therapies and the understanding of influenza virus biology. PMID:15269376

  7. Measurement of airborne influenza virus during hen slaughtering in an ABSL-3E bioBUBBLE®

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several avian viral diseases, including avian influenza, Newcastle disease, infectious bronchitis or laryngotracheitis, are transmitted via respiratory droplets or by contact with contaminated fomites. Using high pathogenicity avian influenza (HPAI) virus as a model, the objective of the present st...

  8. INFLUENZA VIRUS HOST RESISTANCE MODELS IN MICE AND RATS: UTILIZATION FOR UMMUNE FUNCTION ASSESSMENT AND IMMUNOTOXICOLOGY

    EPA Science Inventory

    Each year influenza viruses are responsible for epidemic respiratory diseases with excess morbidity and mortality. he severity of influenza disease ranges from mid upper respiratory tract infections to severe lower respiratory tract infections involving pneumonia, bronchiolitis a...

  9. Detection of Influenza and Other Respiratory Viruses Carried Out in the Influenza Project - Monitoring Vaccine Effectiveness (I-MOVE).

    PubMed

    Woźniak-Kosek, Agnieszka

    2015-01-01

    The project Influenza Vaccine Effectiveness-Monitoring (I-MOVE) is part of the European research carried out by the ECDC (European Center for Disease Prevention and Control), aimed at monitoring the effectiveness of vaccination in Europe during the growing incidence of flu and influenza-like illnesses in the coming epidemic seasons. Laboratory studies using molecular RT-PCR biology methods for detection of genetic material of influenza virus and other respiratory viruses were performed by Voivodeship Sanitary-Epidemiological Stations in Poland. The validation of the results of swabs taken from the nose and throat were carried out in the Department of Influenza Research, National Influenza Center in Warsaw. The study involved 210 samples from patients across Poland. Positive results were recorded for 72.4 % of the samples; influenza virus type A was detected in 43 and type B in 38 cases, whereas in 71 cases other respiratory viruses were detected, which included Human parainfluenza virus type 1-4; Human respiratory syncytial virus type A and B; Human coronavirus 229E/NL63, OC43; Human rhinovirus type A, B, and C; Human enterovirus; and Human adenovirus. The results show that although influenza viruses predominated in the 2010/2011 season in Poland, other flu-like viruses also abounded. PMID:25252895

  10. Influenza virus neuraminidase (NA): a target for antivirals and vaccines.

    PubMed

    Jagadesh, Anitha; Salam, Abdul Ajees Abdul; Mudgal, Piya Paul; Arunkumar, Govindakarnavar

    2016-08-01

    Influenza, the most common infectious disease, poses a great threat to human health because of its highly contagious nature and fast transmissibility, often leading to high morbidity and mortality. Effective vaccination strategies may aid in the prevention and control of recurring epidemics and pandemics associated with this infectious disease. However, antigenic shifts and drifts are major concerns with influenza virus, requiring effective global monitoring and updating of vaccines. Current vaccines are standardized primarily based on the amount of hemagglutinin, a major surface antigen, which chiefly constitutes these preparations along with the varying amounts of neuraminidase (NA). Anti-influenza drugs targeting the active site of NA have been in use for more than a decade now. However, NA has not been approved as an effective antigenic component of the influenza vaccine because of standardization issues. Although some studies have suggested that NA antibodies are able to reduce the severity of the disease and induce a long-term and cross-protective immunity, a few major scientific issues need to be addressed prior to launching NA-based vaccines. Interestingly, an increasing number of studies have shown NA to be a promising target for future influenza vaccines. This review is an attempt to consolidate studies that reflect the strength of NA as a suitable vaccine target. The studies discussed in this article highlight NA as a potential influenza vaccine candidate and support taking the process of developing NA vaccines to the next stage. PMID:27255748

  11. Cause of Flu (Influenza)

    MedlinePlus

    ... Skip Content Marketing Share this: Main Content Area Flu (Influenza) Cause About the Flu Virus Influenza, or flu, is a respiratory infection ... the virus. Influenza A virus. Credit: CDC Where Influenza Comes From In nature, the flu virus is ...

  12. Quantifying homologous and heterologous antibody titre rises after influenza virus infection.

    PubMed

    Freeman, G; Perera, R A P M; Ngan, E; Fang, V J; Cauchemez, S; Ip, D K M; Peiris, J S M; Cowling, B J

    2016-08-01

    Most influenza virus infections are associated with mild disease. One approach to estimate the occurrence of influenza virus infections in individuals is via repeated measurement of humoral antibody titres. We used baseline and convalescent antibody titres measured by haemagglutination inhibition (HI) and viral neutralization (VN) assays against influenza A(H1N1), A(H3N2) and B viruses to investigate the characteristics of antibody rises following virologically confirmed influenza virus infections in participants in a community-based study. Multivariate models were fitted in a Bayesian framework to characterize the distribution of changes in antibody titres following influenza A virus infections. In 122 participants with PCR-confirmed influenza A virus infection, homologous antibody titres rose by geometric means of 1·2- to 10·2-fold after infection with A(H1N1), A(H3N2) and A(H1N1)pdm09. Significant cross-reactions were observed between A(H1N1)pdm09 and seasonal A(H1N1). Antibody titre rises for some subtypes and assays varied by age, receipt of oseltamivir treatment, and recent receipt of influenza vaccination. In conclusion, we provided a quantitative description of the mean and variation in rises in influenza virus antibody titres following influenza virus infection. The multivariate patterns in boosting of antibody titres following influenza virus infection could be taken into account to improve estimates of cumulative incidence of infection in seroepidemiological studies. PMID:27018720

  13. Cyclophilin A protects mice against infection by influenza A virus

    PubMed Central

    Li, Jing; Chen, Can; Wong, Gary; Dong, Wei; Zheng, Weinan; Li, Yun; Sun, Lei; Zhang, Lianfeng; Gao, George F.; Bi, Yuhai; Liu, Wenjun

    2016-01-01

    Our previous studies indicate that Cyclophilin A (CypA) impairs the replication of influenza A virus in vitro. To further evaluate the antiviral functions of CypA and explore its mechanism, transgenic mice with overexpression of CypA by two specific promoters with SPC (CypA-SPC) or CMV (CypA-CMV) were developed. After challenge with the A/WSN/33(H1N1) influenza virus, CypA-SPC and CypA-CMV transgenic mice displayed nearly 2.5- and 3.8-fold stronger disease resistance to virus infection, respectively, compared to wild-type animals. Virus replication, pathological lesions and inflammatory cytokines were substantially reduced in both lines of transgenic mice. In addition, after infection there was an upregulation of genes associated with cell migration, immune function, and organ development; and a downregulation of genes associated with the positive regulation of immune cells and apoptosis in the peritoneal macrophages of CypA-overexpressing transgenic mice (CypA+). These results indicate that CypA is a key modulator of influenza virus resistance in mice, and that CypA+ mice constitutes an important model to study the roles of CypA in the regulation of immune responses and infections. PMID:27354005

  14. Cyclophilin A protects mice against infection by influenza A virus.

    PubMed

    Li, Jing; Chen, Can; Wong, Gary; Dong, Wei; Zheng, Weinan; Li, Yun; Sun, Lei; Zhang, Lianfeng; Gao, George F; Bi, Yuhai; Liu, Wenjun

    2016-01-01

    Our previous studies indicate that Cyclophilin A (CypA) impairs the replication of influenza A virus in vitro. To further evaluate the antiviral functions of CypA and explore its mechanism, transgenic mice with overexpression of CypA by two specific promoters with SPC (CypA-SPC) or CMV (CypA-CMV) were developed. After challenge with the A/WSN/33(H1N1) influenza virus, CypA-SPC and CypA-CMV transgenic mice displayed nearly 2.5- and 3.8-fold stronger disease resistance to virus infection, respectively, compared to wild-type animals. Virus replication, pathological lesions and inflammatory cytokines were substantially reduced in both lines of transgenic mice. In addition, after infection there was an upregulation of genes associated with cell migration, immune function, and organ development; and a downregulation of genes associated with the positive regulation of immune cells and apoptosis in the peritoneal macrophages of CypA-overexpressing transgenic mice (CypA+). These results indicate that CypA is a key modulator of influenza virus resistance in mice, and that CypA+ mice constitutes an important model to study the roles of CypA in the regulation of immune responses and infections. PMID:27354005

  15. Global Reprogramming of Host SUMOylation during Influenza Virus Infection

    PubMed Central

    Domingues, Patricia; Golebiowski, Filip; Tatham, Michael H.; Lopes, Antonio M.; Taggart, Aislynn; Hay, Ronald T.; Hale, Benjamin G.

    2015-01-01

    Summary Dynamic nuclear SUMO modifications play essential roles in orchestrating cellular responses to proteotoxic stress, DNA damage, and DNA virus infection. Here, we describe a non-canonical host SUMOylation response to the nuclear-replicating RNA pathogen, influenza virus, and identify viral RNA polymerase activity as a major contributor to SUMO proteome remodeling. Using quantitative proteomics to compare stress-induced SUMOylation responses, we reveal that influenza virus infection triggers unique re-targeting of SUMO to 63 host proteins involved in transcription, mRNA processing, RNA quality control, and DNA damage repair. This is paralleled by widespread host deSUMOylation. Depletion screening identified ten virus-induced SUMO targets as potential antiviral factors, including C18orf25 and the SMC5/6 and PAF1 complexes. Mechanistic studies further uncovered a role for SUMOylation of the PAF1 complex component, parafibromin (CDC73), in potentiating antiviral gene expression. Our global characterization of influenza virus-triggered SUMO redistribution provides a proteomic resource to understand host nuclear SUMOylation responses to infection. PMID:26549460

  16. Well-tolerated Spirulina extract inhibits influenza virus replication and reduces virus-induced mortality

    PubMed Central

    Chen, Yi-Hsiang; Chang, Gi-Kung; Kuo, Shu-Ming; Huang, Sheng-Yu; Hu, I-Chen; Lo, Yu-Lun; Shih, Shin-Ru

    2016-01-01

    Influenza is one of the most common human respiratory diseases, and represents a serious public health concern. However, the high mutability of influenza viruses has hampered vaccine development, and resistant strains to existing anti-viral drugs have also emerged. Novel anti-influenza therapies are urgently needed, and in this study, we describe the anti-viral properties of a Spirulina (Arthrospira platensis) cold water extract. Anti-viral effects have previously been reported for extracts and specific substances derived from Spirulina, and here we show that this Spirulina cold water extract has low cellular toxicity, and is well-tolerated in animal models at one dose as high as 5,000 mg/kg, or 3,000 mg/kg/day for 14 successive days. Anti-flu efficacy studies revealed that the Spirulina extract inhibited viral plaque formation in a broad range of influenza viruses, including oseltamivir-resistant strains. Spirulina extract was found to act at an early stage of infection to reduce virus yields in cells and improve survival in influenza-infected mice, with inhibition of influenza hemagglutination identified as one of the mechanisms involved. Together, these results suggest that the cold water extract of Spirulina might serve as a safe and effective therapeutic agent to manage influenza outbreaks, and further clinical investigation may be warranted. PMID:27067133

  17. Well-tolerated Spirulina extract inhibits influenza virus replication and reduces virus-induced mortality.

    PubMed

    Chen, Yi-Hsiang; Chang, Gi-Kung; Kuo, Shu-Ming; Huang, Sheng-Yu; Hu, I-Chen; Lo, Yu-Lun; Shih, Shin-Ru

    2016-01-01

    Influenza is one of the most common human respiratory diseases, and represents a serious public health concern. However, the high mutability of influenza viruses has hampered vaccine development, and resistant strains to existing anti-viral drugs have also emerged. Novel anti-influenza therapies are urgently needed, and in this study, we describe the anti-viral properties of a Spirulina (Arthrospira platensis) cold water extract. Anti-viral effects have previously been reported for extracts and specific substances derived from Spirulina, and here we show that this Spirulina cold water extract has low cellular toxicity, and is well-tolerated in animal models at one dose as high as 5,000 mg/kg, or 3,000 mg/kg/day for 14 successive days. Anti-flu efficacy studies revealed that the Spirulina extract inhibited viral plaque formation in a broad range of influenza viruses, including oseltamivir-resistant strains. Spirulina extract was found to act at an early stage of infection to reduce virus yields in cells and improve survival in influenza-infected mice, with inhibition of influenza hemagglutination identified as one of the mechanisms involved. Together, these results suggest that the cold water extract of Spirulina might serve as a safe and effective therapeutic agent to manage influenza outbreaks, and further clinical investigation may be warranted. PMID:27067133

  18. Cryomicroscopy provides structural snapshots of influenza virus membrane fusion.

    PubMed

    Calder, Lesley J; Rosenthal, Peter B

    2016-09-01

    The lipid-enveloped influenza virus enters host cells during infection by binding cell-surface receptors and, after receptor-mediated endocytosis, fusing with the membrane of the endosome and delivering the viral genome and transcription machinery into the host cell. These events are mediated by the hemagglutinin (HA) surface glycoprotein. At the low pH of the endosome, an irreversible conformational change in the HA, including the exposure of the hydrophobic fusion peptide, activates membrane fusion. Here we used electron cryomicroscopy and cryotomography to image the fusion of influenza virus with target membranes at low pH. We visualized structural intermediates of HA and their interactions with membranes during the course of membrane fusion as well as ultrastructural changes in the virus that accompany membrane fusion. Our observations are relevant to a wide range of protein-mediated membrane-fusion processes and demonstrate how dynamic membrane events may be studied by cryomicroscopy. PMID:27501535

  19. Cross-protective immunity to influenza A viruses.

    PubMed

    Epstein, Suzanne L; Price, Graeme E

    2010-11-01

    Antigenic changes in influenza virus occur gradually, owing to mutations (antigenic drift), and abruptly, owing to reassortment among subtypes (antigenic shift). Availability of strain-matched vaccines often lags behind these changes, resulting in a shortfall in public health. In animal models, cross-protection by vaccines based on conserved antigens does not completely prevent infection, but greatly reduces morbidity, mortality, virus replication and, thus, viral shedding and spread. Such immunity is especially effective and long-lasting with mucosal administration. Cross-protective immunity in humans is controversial, but is suggested by some epidemiological findings. 'Universal' vaccines protective against all influenza A viruses might substantially reduce severity of infection and limit spread of disease during outbreaks. These vaccines could be used 'off the shelf' early in an outbreak or pandemic, before strain-matched vaccines are available. PMID:21087110

  20. Universal antibodies against the highly conserved influenza fusion peptide cross-neutralize several subtypes of influenza A virus

    SciTech Connect

    Hashem, Anwar M.; Van Domselaar, Gary; Li, Changgui; Wang, Junzhi; She, Yi-Min; Cyr, Terry D.; Sui, Jianhua; He, Runtao; Marasco, Wayne A.; Li, Xuguang

    2010-12-10

    Research highlights: {yields} The fusion peptide is the only universally conserved epitope in all influenza viral hemagglutinins. {yields} Anti-fusion peptide antibodies are universal antibodies that cross-react with all influenza HA subtypes. {yields} The universal antibodies cross-neutralize different influenza A subtypes. {yields} The universal antibodies inhibit the fusion process between the viruses and the target cells. -- Abstract: The fusion peptide of influenza viral hemagglutinin plays a critical role in virus entry by facilitating membrane fusion between the virus and target cells. As the fusion peptide is the only universally conserved epitope in all influenza A and B viruses, it could be an attractive target for vaccine-induced immune responses. We previously reported that antibodies targeting the first 14 amino acids of the N-terminus of the fusion peptide could bind to virtually all influenza virus strains and quantify hemagglutinins in vaccines produced in embryonated eggs. Here we demonstrate that these universal antibodies bind to the viral hemagglutinins in native conformation presented in infected mammalian cell cultures and neutralize multiple subtypes of virus by inhibiting the pH-dependant fusion of viral and cellular membranes. These results suggest that this unique, highly-conserved linear sequence in viral hemagglutinin is exposed sufficiently to be attacked by the antibodies during the course of infection and merits further investigation because of potential importance in the protection against diverse strains of influenza viruses.

  1. The affect of infectious bursal disease virus on avian influenza virus vaccine efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immunosuppressive viruses are known to affect vaccinal immunity, however the impact of virally induced immunosuppression on avian influenza vaccine efficacy has not been quantified. In order to determine the effect of exposure to infectious bursal disease virus (IBDV) on vaccinal immunity to highly ...

  2. Oligonucleotide microarray for subtyping of influenza A viruses

    NASA Astrophysics Data System (ADS)

    Klotchenko, S. A.; Vasin, A. V.; Sandybaev, N. T.; Plotnikova, M. A.; Chervyakova, O. V.; Smirnova, E. A.; Kushnareva, E. V.; Strochkov, V. M.; Taylakova, E. T.; Egorov, V. V.; Koshemetov, J. K.; Kiselev, O. I.; Sansyzbay, A. R.

    2012-02-01

    Influenza is one of the most widespread respiratory viral diseases, infecting humans, horses, pigs, poultry and some other animal populations. Influenza A viruses (IAV) are classified into subtypes on the basis of the surface hemagglutinin (H1 to H16) and neuraminidase (N1 to N9) glycoproteins. The correct determination of IAV subtype is necessary for clinical and epidemiological studies. In this article we propose an oligonucleotide microarray for subtyping of IAV using universal one-step multisegment RT-PCR fluorescent labeling of viral gene segments. It showed to be an advanced approach for fast detection and identification of IAV.

  3. In ovo and in vitro susceptibility of American alligators (Alligator mississippiensis) to avian influenza virus infection.

    PubMed

    Temple, Bradley L; Finger, John W; Jones, Cheryl A; Gabbard, Jon D; Jelesijevic, Tomislav; Uhl, Elizabeth W; Hogan, Robert J; Glenn, Travis C; Tompkins, S Mark

    2015-01-01

    Avian influenza has emerged as one of the most ubiquitous viruses within our biosphere. Wild aquatic birds are believed to be the primary reservoir of all influenza viruses; however, the spillover of H5N1 highly pathogenic avian influenza (HPAI) and the recent swine-origin pandemic H1N1 viruses have sparked increased interest in identifying and understanding which and how many species can be infected. Moreover, novel influenza virus sequences were recently isolated from New World bats. Crocodilians have a slow rate of molecular evolution and are the sister group to birds; thus they are a logical reptilian group to explore susceptibility to influenza virus infection and they provide a link between birds and mammals. A primary American alligator (Alligator mississippiensis) cell line, and embryos, were infected with four, low pathogenic avian influenza (LPAI) strains to assess susceptibility to infection. Embryonated alligator eggs supported virus replication, as evidenced by the influenza virus M gene and infectious virus detected in allantoic fluid and by virus antigen staining in embryo tissues. Primary alligator cells were also inoculated with the LPAI viruses and showed susceptibility based upon antigen staining; however, the requirement for trypsin to support replication in cell culture limited replication. To assess influenza virus replication in culture, primary alligator cells were inoculated with H1N1 human influenza or H5N1 HPAI viruses that replicate independent of trypsin. Both viruses replicated efficiently in culture, even at the 30 C temperature preferred by the alligator cells. This research demonstrates the ability of wild-type influenza viruses to infect and replicate within two crocodilian substrates and suggests the need for further research to assess crocodilians as a species potentially susceptible to influenza virus infection. PMID:25380354

  4. 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

  5. Rapid semiautomated subtyping of influenza virus species during the 2009 swine origin influenza A H1N1 virus epidemic in Milwaukee, Wisconsin.

    PubMed

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

    2009-09-01

    In the spring of 2009, a novel influenza A (H1N1) virus (swine origin influenza virus [S-OIV]) emerged and began causing a large outbreak of illness in Milwaukee, WI. Our group at the Midwest Respiratory Virus Program laboratory developed a semiautomated real-time multiplex reverse transcription-PCR assay (Seasonal), employing the NucliSENS easyMAG system (bioMérieux, Durham, NC) and a Raider thermocycler (HandyLab Inc., Ann Arbor, MI), that typed influenza A virus, influenza B virus, and respiratory syncytial virus (RSV) and subtyped influenza A virus into the currently circulating H1 and H3 subtypes, as well as a similar assay that identified H1 of S-OIV. The Seasonal and H1 S-OIV assays demonstrated analytical limits of detection of <50 50% tissue culture infective doses/ml and 3 to 30 input copies, respectively. Testing of the analytical specificities revealed no cross-reactivity with 41 and 26 different common organisms and demonstrated outstanding reproducibility of results. Clinical testing showed 95% sensitivity for influenza A virus and influenza B virus and 95 and 97% specificity compared to tissue culture. Comparisons of results from other molecular tests showed levels of positive agreement with the Seasonal and H1 S-OIV assay results of 99 and 100% and levels of negative agreement of 98 and 100%. This study has demonstrated the use of a semiautomated system for sensitive, specific, and rapid detection of influenza A virus, influenza B virus, and RSV and subtyping of influenza A virus into human H1 and H3 and S-OIV strains. This assay/system performed well in clinical testing of regular seasonal influenza virus subtypes and was outstanding during the 2009 Milwaukee S-OIV infection outbreak. This recent outbreak of infection with a novel influenza A (H1N1) virus also demonstrates the importance of quickly distributing information on new agents and of having rapid influenza virus subtyping assays widely available for clinical and public health decisions

  6. Susceptibility of swine to H5 and H7 low pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of pigs to become infected with low pathogenic avian influenza (LPAI) viruses from an avian reservoir, and then generate mammalian adaptable influenza A viruses (IAVs) is difficult to determine. Yet, it is an important link to understanding any relationship between LPAI virus ecology and...

  7. Antigenic cartographic analysis of H7 avian influenza viruses with chicken serum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antigenic cartography is a relatively new method that can be used to evaluate the antigenic relatedness among avian influenza virus isolates. Evaluation of antigenic relationships among avian influenza viruses can be applied to vaccine design and to understanding the evolution of the virus. Initia...

  8. Human Infection with Highly Pathogenic A(H7N7) Avian Influenza Virus, Italy, 2013

    PubMed Central

    Rossini, Giada; Facchini, Marzia; Vaccari, Gabriele; Di Trani, Livia; Di Martino, Angela; Gaibani, Paolo; Vocale, Caterina; Cattoli, Giovanni; Bennett, Michael; McCauley, John W.; Rezza, Giovanni; Moro, Maria Luisa; Rangoni, Roberto; Finarelli, Alba Carola; Landini, Maria Paola; Castrucci, Maria Rita; Donatelli, Isabella

    2014-01-01

    During an influenza A(H7N7) virus outbreak among poultry in Italy during August–September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms. PMID:25271444

  9. Avian influenza A viruses in birds --an ecological, ornithological and virological view.

    PubMed

    Kaleta, E F; Hergarten, G; Yilmaz, A

    2005-12-01

    Avian influenza A viruses (AIV) are the causative agents of the presently most important poultry disease. Ten countries in Asia and several other countries in Eastern Europe suffer high losses from the lethal effects of these viruses of the H5N1 subtype. AIV of other subtypes cause in additional countries severe losses. The threat to health and well-being of the avifauna, domestic poultry and possibly mammals including humans are worldwide of major concern. The European Union reacted with a complete import ban on untreated meat, eggs, poultry products as well as free-living and pet birds. Extensive surveillance of free-living birds and domestic poultry that is maintained in free-range and close to open waters were initiated in an attempt to gather information on the current status of infection with these viruses and to target appropriate countermeasures for the protection of domestic poultry (in-house keeping) and to safeguard food production for humans. Since the monitoring of free-living birds is labour-intensive, costly, and time-consuming, only birds should be included in the monitoring programme that harboured in the past most if not all influenza A viruses. The birds of the order Anatiformes, family Anatidae, subfamilies Anserinae and Anatinae, provided 65.9 % of all avian AIV isolates. The cosmopolitan Common Mallard (Anas platyrhynchos) is the dominant species with the highest rate of isolations among all bird species. Second in frequency is the North-American Blue-winged Teal (Spatula discors). Consequently, free-living anatiform birds of the genera Anas and Spatula should comprise the main focus for the collection of cloacal and pharyngeal swabs. With the likely exception of the most recent H5N1 viruses, signs of disease were not recorded in AIV infected anatiform birds. AIV isolations were definitely less frequently obtained from birds of the orders Phasianiformes (including domestic chickens and turkeys), Charadriiformes (plovers and lapwings

  10. Equine Influenza A(H3N8) Virus Isolated from Bactrian Camel, Mongolia

    PubMed Central

    Yondon, Myagmarsukh; Zayat, Batsukh; Nelson, Martha I.; Heil, Gary L.; Anderson, Benjamin D.; Lin, Xudong; Halpin, Rebecca A.; McKenzie, Pamela P.; White, Sarah K.; Wentworth, David E.

    2014-01-01

    Because little is known about the ecology of influenza viruses in camels, 460 nasal swab specimens were collected from healthy (no overt illness) Bactrian camels in Mongolia during 2012. One specimen was positive for influenza A virus (A/camel/Mongolia/335/2012[H3N8]), which is phylogenetically related to equine influenza A(H3N8) viruses and probably represents natural horse-to-camel transmission. PMID:25418532

  11. Fitness seascapes and adaptive evolution of the influenza virus

    NASA Astrophysics Data System (ADS)

    Lassig, Michael

    2014-03-01

    The seasonal human influenza A virus undergoes rapid genome evolution. This process is triggered by interactions with the host immune system and produces significant year-to-year sequence turnover in the population of circulating viral strains. We develop a dynamical fitness model that predicts the evolution of the viral population from one year to the next. Two factors are shown to determine the fitness of a viral strain: adaptive changes, which are under positive selection, and deleterious mutations, which affect conserved viral functions such as protein stability. Combined with the influenza strain tree, this fitness model maps the adaptive history of influenza A. We discuss the implications of our results for the statistical theory of adaptive evolution in asexual populations. Based on this and related systems, we touch upon the fundamental question of when evolution can be predicted. Joint work with Marta Luksza, Columbia University.

  12. Antiviral adhesion molecular mechanisms for influenza: W. G. Laver's lifetime obsession

    PubMed Central

    Garman, Elspeth F.

    2015-01-01

    Infection by the influenza virus depends firstly on cell adhesion via the sialic-acid-binding viral surface protein, haemagglutinin, and secondly on the successful escape of progeny viruses from the host cell to enable the virus to spread to other cells. To achieve the latter, influenza uses another glycoprotein, the enzyme neuraminidase (NA), to cleave the sialic acid receptors from the surface of the original host cell. This paper traces the development of anti-influenza drugs, from the initial suggestion by MacFarlane Burnet in 1948 that an effective ‘competitive poison’ of the virus' NA might be useful in controlling infection by the virus, through to the determination of the structure of NA by X-ray crystallography and the realization of Burnet's idea with the design of NA inhibitors. A focus is the contribution of the late William Graeme Laver, FRS, to this research. PMID:25533092

  13. Protection of chickens against H5N1 highly pathogenic avian influenza virus infection by live vaccination with infectious laryngotracheitis virus recombinants expressing H5 hemagglutinin and N1 neuraminidase.

    PubMed

    Pavlova, Sophia P; Veits, Jutta; Keil, Günther M; Mettenleiter, Thomas C; Fuchs, Walter

    2009-01-29

    Attenuated vaccine strains of the alphaherpesvirus causing infectious laryngotracheitis of chickens (ILTV, gallid herpesvirus 1) can be used for mass application. Previously, we showed that live virus vaccination with recombinant ILTV expressing hemagglutinin of highly pathogenic avian influenza viruses (HPAIV) protected chickens against ILT and fowl plague caused by HPAIV carrying the corresponding hemagglutinin subtypes [Lüschow D, Werner O, Mettenleiter TC, Fuchs W. Protection of chickens from lethal avian influenza A virus infection by live-virus vaccination with infectious laryngotracheitis virus recombinants expressing the hemagglutinin (H5) gene. Vaccine 2001;19(30):4249-59; Veits J, Lüschow D, Kindermann K, Werner O, Teifke JP, Mettenleiter TC, et al. Deletion of the non-essential UL0 gene of infectious laryngotracheitis (ILT) virus leads to attenuation in chickens, and UL0 mutants expressing influenza virus haemagglutinin (H7) protect against ILT and fowl plague. J Gen Virol 2003;84(12):3343-52]. However, protection against H5N1 HPAIV was not satisfactory. Therefore, a newly designed dUTPase-negative ILTV vector was used for rapid insertion of the H5-hemagglutinin, or N1-neuraminidase genes of a recent H5N1 HPAIV isolate. Compared to our previous constructs, protein expression was considerably enhanced by insertion of synthetic introns downstream of the human cytomegalovirus immediate-early promoter within the 5'-nontranslated region of the transgenes. Deletion of the viral dUTPase gene did not affect in vitro replication of the ILTV recombinants, but led to sufficient attenuation in vivo. After a single ocular immunization, all chickens developed H5- or N1-specific serum antibodies. Nevertheless, animals immunized with N1-ILTV died after subsequent H5N1 HPAIV challenge, although survival times were prolonged compared to non-vaccinated controls. In contrast, all chickens vaccinated with either H5-ILTV alone, or H5- and N1-ILTV simultaneously, survived

  14. Identifying Selection in the Within-Host Evolution of Influenza Using Viral Sequence Data

    PubMed Central

    Illingworth, Christopher J. R.; Fischer, Andrej; Mustonen, Ville

    2014-01-01

    The within-host evolution of influenza is a vital component of its epidemiology. A question of particular interest is the role that selection plays in shaping the viral population over the course of a single infection. We here describe a method to measure selection acting upon the influenza virus within an individual host, based upon time-resolved genome sequence data from an infection. Analysing sequence data from a transmission study conducted in pigs, describing part of the haemagglutinin gene (HA1) of an influenza virus, we find signatures of non-neutrality in six of a total of sixteen infections. We find evidence for both positive and negative selection acting upon specific alleles, while in three cases, the data suggest the presence of time-dependent selection. In one infection we observe what is potentially a specific immune response against the virus; a non-synonymous mutation in an epitope region of the virus is found to be under initially positive, then strongly negative selection. Crucially, given the lack of homologous recombination in influenza, our method accounts for linkage disequilibrium between nucleotides at different positions in the haemagglutinin gene, allowing for the analysis of populations in which multiple mutations are present at any given time. Our approach offers a new insight into the dynamics of influenza infection, providing a detailed characterisation of the forces that underlie viral evolution. PMID:25080215

  15. Detection of Evolutionarily Distinct Avian Influenza A Viruses in Antarctica

    PubMed Central

    Vijaykrishna, Dhanasekaran; Butler, Jeffrey; Baas, Chantal; Maurer-Stroh, Sebastian; Silva-de-la-Fuente, M. Carolina; Medina-Vogel, Gonzalo; Olsen, Bjorn; Kelso, Anne; Barr, Ian G.; González-Acuña, Daniel

    2014-01-01

    ABSTRACT Distinct lineages of avian influenza viruses (AIVs) are harbored by spatially segregated birds, yet significant surveillance gaps exist around the globe. Virtually nothing is known from the Antarctic. Using virus culture, molecular analysis, full genome sequencing, and serology of samples from Adélie penguins in Antarctica, we confirmed infection by H11N2 subtype AIVs. Their genetic segments were distinct from all known contemporary influenza viruses, including South American AIVs, suggesting spatial separation from other lineages. Only in the matrix and polymerase acidic gene phylogenies did the Antarctic sequences form a sister relationship to South American AIVs, whereas distant phylogenetic relationships were evident in all other gene segments. Interestingly, their neuraminidase genes formed a distant relationship to all avian and human influenza lineages, and the polymerase basic 1 and polymerase acidic formed a sister relationship to the equine H3N8 influenza virus lineage that emerged during 1963 and whose avian origins were previously unknown. We also estimated that each gene segment had diverged for 49 to 80 years from its most closely related sequences, highlighting a significant gap in our AIV knowledge in the region. We also show that the receptor binding properties of the H11N2 viruses are predominantly avian and that they were unable to replicate efficiently in experimentally inoculated ferrets, suggesting their continuous evolution in avian hosts. These findings add substantially to our understanding of both the ecology and the intra- and intercontinental movement of Antarctic AIVs and highlight the potential risk of an incursion of highly pathogenic AIVs into this fragile environment. PMID:24803521

  16. A practical approach to genetic screening for influenza virus variants.

    PubMed Central

    Zou, S

    1997-01-01

    This report describes a quick genetic approach to the screening of influenza virus variants. Multiplex reverse transcription (MRT) and multiplex PCR (MPCR) were used to amplify and differentiate the hemagglutinin (HA) genes of different types and subtypes of influenza viruses. Heteroduplex mobility assay (HMA) was then used to differentiate strains within the same type and subtype. Three primers complementary to the consensus 3' termini of viral genomic RNA segments of human influenza virus types A, B, and C were used in a single MRT reaction to prime the synthesis of cDNA of all the viral genome segments. The cDNA was then amplified in an MPCR containing primers for the HA genes of the H1 and H3 subtypes of type A, the HA gene of type B, and the counterpart of type C virus. Amplicons of the different types and subtypes differ in size, thus allowing typing and subtyping. The regions amplified cover most of the HA1 portion of the HA genes and therefore amplicons of variants identified by the described HMA can be sequenced directly. In the HMA, the amplicon of an individual strain was mixed with that of a reference strain and heteroduplexes derived from mismatches migrated more slowly than homoduplexes of the same size in electrophoresis, with the mobility shift pattern indicating the divergence of amplicons. The whole process from viral RNA extraction to HMA can be completed within 2 days and thus provides a quick screening before further analysis by hemagglutination inhibition testing and sequencing. In addition, all segments of the viral genome can be amplified from a single MRT reaction, which can yield valuable sources of products for future genetic analyses. This method should facilitate genetic screening and characterization of influenza virus variants. PMID:9316919

  17. Influenza vaccine effectiveness in preventing inpatient and outpatient cases in a season dominated by vaccine-matched influenza B virus

    PubMed Central

    Martínez-Baz, Iván; Navascués, Ana; Pozo, Francisco; Chamorro, Judith; Albeniz, Esther; Casado, Itziar; Reina, Gabriel; Cenoz, Manuel García; Ezpeleta, Carmen; Castilla, Jesús

    2015-01-01

    Studies that have evaluated the influenza vaccine effectiveness (VE) to prevent laboratory-confirmed influenza B cases are uncommon, and few have analyzed the effect in preventing hospitalized cases. We have evaluated the influenza VE in preventing outpatient and hospitalized cases with laboratory-confirmed influenza in the 2012–2013 season, which was dominated by a vaccine-matched influenza B virus. In the population covered by the Navarra Health Service, all hospitalized patients with influenza-like illness (ILI) and all ILI patients attended by a sentinel network of general practitioners were swabbed for influenza testing, and all were included in a test-negative case-control analysis. VE was calculated as (1-odds ratio)×100. Among 744 patients tested, 382 (51%) were positive for influenza virus: 70% for influenza B, 24% for A(H1N1)pdm09, and 5% for A(H3N2). The overall estimate of VE in preventing laboratory-confirmed influenza was 63% (95% confidence interval (CI): 34 to 79), 55% (1 to 80) in outpatients and 74% (33 to 90) in hospitalized patients. The VE was 70% (41 to 85) against influenza B and 43% (−45 to 78) against influenza A. The VE against virus B was 87% (52 to 96) in hospitalized patients and 56% in outpatients (−5 to 81). Adjusted comparison of vaccination status between inpatient and outpatient cases with influenza B did not show statistically significant differences (odds ratio: 1.13; p = 0.878). These results suggest a high protective effect of the vaccine in the 2012–2013 season, with no differences found for the effect between outpatient and hospitalized cases. PMID:25996366

  18. Influenza virus assays based on virus‐inducible reporter cell lines

    PubMed Central

    Li, Yunsheng; Larrimer, Audrey; Curtiss, Teresa; Kim, Jaekyung; Jones, Abby; Baird‐Tomlinson, Heather; Pekosz, Andrew; Olivo, Paul D.

    2009-01-01

    Background  Virus‐inducible reporter genes have been used as the basis of virus detection and quantitation assays for a number of viruses. A strategy for influenza A virus‐induction of a reporter gene was recently described. In this report, we describe the extension of this strategy to influenza B virus, the generation of stable cell lines with influenza A and B virus‐inducible reporter genes, and the use of these cells in various clinically relevant viral assays. Each of the cell lines described herein constitutively express an RNA transcript that contains a reporter gene coding region flanked by viral 5′‐ and 3′‐untranslated regions (UTR) and therefore mimics an influenza virus genomic segment. Upon infection of the cells with influenza virus the virus‐inducible reporter gene segment (VIRGS) is replicated and transcribed by the viral polymerase complex resulting in reporter gene expression. Findings  Reporter gene induction occurs after infection with a number of laboratory strains and clinical isolates of influenza virus including several H5N1 strains. The induction is dose‐dependent and highly specific for influenza A or influenza B viruses. Conclusions  These cell lines provide the basis of simple, rapid, and objective assays that involve virus quantitation such as determination of viral titer, assessment of antiviral susceptibility, and determination of antibody neutralization titer. These cell lines could be very useful for influenza virus researchers and vaccine manufacturers. PMID:21462401

  19. Epidemiology and Genetic Characterization of H3N8 Equine Influenza Virus Responsible for Clinical Disease in Algeria in 2011.

    PubMed

    Laabassi, F; Lecouturier, F; Amelot, G; Gaudaire, D; Mamache, B; Laugier, C; Legrand, L; Zientara, S; Hans, A

    2015-12-01

    An outbreak of equine influenza (EI) was reported in Algeria between May and July, 2011. The outbreak started in Tiaret, in west province of Algeria, and spread to the other parts of the country affecting almost 900 horses in many provinces. The population studied was composed of 325 horses from different groups of age. Clinical sign expression was age dependent. Indeed, a morbidity rate of 14.9% was observed in horses under 15 months old and a rate of 4.95% in horses over 8 years old. Interestingly, the morbidity rate raised sharply to reach 100% in horses aged between 18 months and 7 years. The virus (H3N8) was detected in nasopharyngeal swabs (n = 11) from non-vaccinated horses using a qRT-PCR targeting a portion of the gene encoding the matrix protein (M). The virus isolates were identified as H3N8 by sequencing the haemagglutinin (HA) and neuraminidase (NA) genes and were named from A/equine/Tiaret/1/2011 to A/equine/Tiaret/10/2011. Alignment of HA1 amino acid sequence confirmed that viruses belong to Clade 2 of the Florida sublineage in the American lineage. Moreover, they are closely related to A/equine/Yokohama/aq13/2010, A/equine/Eyragues/1/2010, A/equine/Bokel/2011 and A/equine/Lichtenfeld/2012. Our data indicate that this strain was also circulating in the European horse population in 2010, 2011 and 2012. PMID:24472362

  20. CT findings in viral lower respiratory tract infections caused by parainfluenza virus, influenza virus and respiratory syncytial virus

    PubMed Central

    Kim, Min-Chul; Kim, Mi Young; Lee, Hyun Joo; Lee, Sang-Oh; Choi, Sang-Ho; Kim, Yang Soo; Woo, Jun Hee; Kim, Sung-Han

    2016-01-01

    Abstract Viral lower respiratory tract infections (LRTIs) can present with a variety of computed tomography (CT) findings. However, identifying the contribution of a particular virus to CT findings is challenging due to concomitant infections and the limited data on the CT findings in viral LRTIs. We therefore investigate the CT findings in different pure viral LRTIs. All patients who underwent bronchoalveolar lavage (BAL) and were diagnosed with LRTIs caused by parainfluenza virus (PIV), influenza virus, or respiratory syncytial virus (RSV) between 1998 and 2014 were enrolled in a tertiary hospital in Seoul, South Korea. A pure viral LRTI was defined as a positive viral culture from BAL without any positive evidence from respiratory or blood cultures, or from polymerase chain reaction (PCR), or from serologic tests for bacteria, fungi, mycobacteria, or other viruses. CT images of 40 patients with viral LRTIs were analyzed: 14 with PIV, 14 with influenza virus, and 12 with RSV. Patch consolidation (≥1 cm or more than 1 segmental level) was found only in PIV (29%) (P = 0.03), by which CT findings caused by PIV could resemble those seen in bacterial LRTIs. Ground-glass opacities were seen in all cases of influenza virus and were more frequent than in PIV (71%) and RSV (67%) (P = 0.05). Bronchial wall thickening was more common in influenza virus (71%) and RSV (67%) LRTIs than PIV LRTIs (21%) (P = 0.02). With respect to anatomical distribution, PIV infections generally affected the lower lobes (69%), while influenza virus mostly caused diffuse changes throughout the lungs (57%), and RSV frequently formed localized patterns in the upper and mid lobes (44%). The CT findings in LRTIs of PIV, influenza virus, and RSV can be distinguished by certain characteristics. These differences could be useful for early differentiation of these viral LRTIs, and empirical use of appropriate antiviral agents. PMID:27368011

  1. Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections.

    PubMed

    Horm, Srey Viseth; Tarantola, Arnaud; Rith, Sareth; Ly, Sowath; Gambaretti, Juliette; Duong, Veasna; Y, Phalla; Sorn, San; Holl, Davun; Allal, Lotfi; Kalpravidh, Wantanee; Dussart, Philippe; Horwood, Paul F; Buchy, Philippe

    2016-01-01

    Surveillance for avian influenza viruses (AIVs) in poultry and environmental samples was conducted in four live-bird markets in Cambodia from January through November 2013. Through real-time RT-PCR testing, AIVs were detected in 45% of 1048 samples collected throughout the year. Detection rates ranged from 32% and 18% in duck and chicken swabs, respectively, to 75% in carcass wash water samples. Influenza A/H5N1 virus was detected in 79% of samples positive for influenza A virus and 35% of all samples collected. Sequence analysis of full-length haemagglutinin (HA) and neuraminidase (NA) genes from A/H5N1 viruses, and full-genome analysis of six representative isolates, revealed that the clade 1.1.2 reassortant virus associated with Cambodian human cases during 2013 was the only A/H5N1 virus detected during the year. However, multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of HA and NA genes revealed co-circulation of at least nine low pathogenic AIVs from HA1, HA2, HA3, HA4, HA6, HA7, HA9, HA10 and HA11 subtypes. Four repeated serological surveys were conducted throughout the year in a cohort of 125 poultry workers. Serological testing found an overall prevalence of 4.5% and 1.8% for antibodies to A/H5N1 and A/H9N2, respectively. Seroconversion rates of 3.7 and 0.9 cases per 1000 person-months participation were detected for A/H5N1 and A/H9N2, respectively. Peak AIV circulation was associated with the Lunar New Year festival. Knowledge of periods of increased circulation of avian influenza in markets should inform intervention measures such as market cleaning and closures to reduce risk of human infections and emergence of novel AIVs. PMID:27436362

  2. Avian Influenza Viruses, Inflammation, and CD8(+) T Cell Immunity.

    PubMed

    Wang, Zhongfang; Loh, Liyen; Kedzierski, Lukasz; Kedzierska, Katherine

    2016-01-01

    Avian influenza viruses (AIVs) circulate naturally in wild aquatic birds, infect domestic poultry, and are capable of causing sporadic bird-to-human transmissions. AIVs capable of infecting humans include a highly pathogenic AIV H5N1, first detected in humans in 1997, and a low pathogenic AIV H7N9, reported in humans in 2013. Both H5N1 and H7N9 cause severe influenza disease in humans, manifested by acute respiratory distress syndrome, multi-organ failure, and high mortality rates of 60% and 35%, respectively. Ongoing circulation of H5N1 and H7N9 viruses in wild birds and poultry, and their ability to infect humans emphasizes their epidemic and pandemic potential and poses a public health threat. It is, thus, imperative to understand the host immune responses to the AIVs so we can control severe influenza disease caused by H5N1 or H7N9 and rationally design new immunotherapies and vaccines. This review summarizes our current knowledge on AIV epidemiology, disease symptoms, inflammatory processes underlying the AIV infection in humans, and recent studies on universal pre-existing CD8(+) T cell immunity to AIVs. Immune responses driving the host recovery from AIV infection in patients hospitalized with severe influenza disease are also discussed. PMID:26973644

  3. Avian Influenza Viruses, Inflammation, and CD8+ T Cell Immunity

    PubMed Central

    Wang, Zhongfang; Loh, Liyen; Kedzierski, Lukasz; Kedzierska, Katherine

    2016-01-01

    Avian influenza viruses (AIVs) circulate naturally in wild aquatic birds, infect domestic poultry, and are capable of causing sporadic bird-to-human transmissions. AIVs capable of infecting humans include a highly pathogenic AIV H5N1, first detected in humans in 1997, and a low pathogenic AIV H7N9, reported in humans in 2013. Both H5N1 and H7N9 cause severe influenza disease in humans, manifested by acute respiratory distress syndrome, multi-organ failure, and high mortality rates of 60% and 35%, respectively. Ongoing circulation of H5N1 and H7N9 viruses in wild birds and poultry, and their ability to infect humans emphasizes their epidemic and pandemic potential and poses a public health threat. It is, thus, imperative to understand the host immune responses to the AIVs so we can control severe influenza disease caused by H5N1 or H7N9 and rationally design new immunotherapies and vaccines. This review summarizes our current knowledge on AIV epidemiology, disease symptoms, inflammatory processes underlying the AIV infection in humans, and recent studies on universal pre-existing CD8+ T cell immunity to AIVs. Immune responses driving the host recovery from AIV infection in patients hospitalized with severe influenza disease are also discussed. PMID:26973644

  4. Dual Mutation Events in the Haemagglutinin-Esterase and Fusion Protein from an Infectious Salmon Anaemia Virus HPR0 Genotype Promote Viral Fusion and Activation by an Ubiquitous Host Protease

    PubMed Central

    Fourrier, Mickael; Lester, Katherine; Markussen, Turhan; Falk, Knut; Secombes, Christopher J.; McBeath, Alastair; Collet, Bertrand

    2015-01-01

    In Infectious salmon anaemia virus (ISAV), deletions in the highly polymorphic region (HPR) in the near membrane domain of the haemagglutinin-esterase (HE) stalk, influence viral fusion. It is suspected that selected mutations in the associated Fusion (F) protein may also be important in regulating fusion activity. To better understand the underlying mechanisms involved in ISAV fusion, several mutated F proteins were generated from the Scottish Nevis and Norwegian SK779/06 HPR0. Co-transfection with constructs encoding HE and F were performed, fusion activity assessed by content mixing assay and the degree of proteolytic cleavage by western blot. Substitutions in Nevis F demonstrated that K276 was the most likely cleavage site in the protein. Furthermore, amino acid substitutions at three sites and two insertions, all slightly upstream of K276, increased fusion activity. Co-expression with HE harbouring a full-length HPR produced high fusion activities when trypsin and low pH were applied. In comparison, under normal culture conditions, groups containing a mutated HE with an HPR deletion were able to generate moderate fusion levels, while those with a full length HPR HE could not induce fusion. This suggested that HPR length may influence how the HE primes the F protein and promotes fusion activation by an ubiquitous host protease and/or facilitate subsequent post-cleavage refolding steps. Variations in fusion activity through accumulated mutations on surface glycoproteins have also been reported in other orthomyxoviruses and paramyxoviruses. This may in part contribute to the different virulence and tissue tropism reported for HPR0 and HPR deleted ISAV genotypes. PMID:26517828

  5. Antibody-Dependent Cell-Mediated Cytotoxicity to Hemagglutinin of Influenza A Viruses After Influenza Vaccination in Humans

    PubMed Central

    Zhong, Weimin; Liu, Feng; Wilson, Jason R.; Holiday, Crystal; Li, Zhu-Nan; Bai, Yaohui; Tzeng, Wen-Pin; Stevens, James; York, Ian A.; Levine, Min Z.

    2016-01-01

    Background. Detection of neutralizing antibodies (nAbs) to influenza A virus hemagglutinin (HA) antigens by conventional serological assays is currently the main immune correlate of protection for influenza vaccines However, current prepandemic avian influenza vaccines are poorly immunogenic in inducing nAbs despite considerable protection conferred. Recent studies show that Ab-dependent cell-mediated cytotoxicity (ADCC) to HA antigens are readily detectable in the sera of healthy individuals and patients with influenza infection. Methods. Virus neutralization and ADCC activities of serum samples from individuals who received either seasonal or a stock-piled H5N1 avian influenza vaccine were evaluated by hemagglutination inhibition assay, microneutralization assay, and an improved ADCC natural killer (NK) cell activation assay. Results. Immunization with inactivated seasonal influenza vaccine led to strong expansion of both nAbs and ADCC-mediating antibodies (adccAbs) to H3 antigen of the vaccine virus in 24 postvaccination human sera. In sharp contrast, 18 individuals vaccinated with the adjuvanted H5N1 avian influenza vaccine mounted H5-specific antibodies with strong ADCC activities despite moderate virus neutralization capacity. Strength of HA-specific ADCC activities is largely associated with the titers of HA-binding antibodies and not with the fine antigenic specificity of anti-HA nAbs. Conclusions. Detection of both nAbs and adccAbs may better reflect protective capacity of HA-specific antibodies induced by avian influenza vaccines.

  6. Surveillance of avian influenza viruses in Papua New Guinean poultry, June 2011 to April 2012

    PubMed Central

    Jonduo, Marinjho; Wong, Sook-San; Kapo, Nime; Ominipi, Paskalis; Abdad, Mohammad; Siba, Peter; McKenzie, Pamela; Webby, Richard

    2013-01-01

    We investigated the circulation of avian influenza viruses in poultry populations throughout Papua New Guinea to assess the risk to the poultry industry and human health. Oropharyngeal swabs, cloacal swabs and serum were collected from 537 poultry from 14 provinces of Papua New Guinea over an 11–month period (June 2011 through April 2012). Virological and serological investigations were undertaken to determine the prevalence of avian influenza viruses. Neither influenza A viruses nor antibodies were detected in any of the samples. This study demonstrated that avian influenza viruses were not circulating at detectable levels in poultry populations in Papua New Guinea during the sampling period. However, avian influenza remains a significant risk to Papua New Guinea due to the close proximity of countries having previously reported highly pathogenic avian influenza viruses and the low biosecurity precautions associated with the rearing of most poultry populations in the country. PMID:24478918

  7. Influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The term "influenza" originally referred to epidemics of acute, rapidly spreading catarrhal fevers of humans caused by viruses in the family Orthomyxoviridae. Today, orthomyxoviruses are recognized as the cause of significant numbers of natural infections and disease, usually of the upper respirato...

  8. Domestic Pigs Are Susceptible to Infection with Influenza B Viruses

    PubMed Central

    Ran, Zhiguang; Shen, Huigang; Lang, Yuekun; Kolb, Elizabeth A.; Turan, Nuri; Zhu, Laihua; Ma, Jingjiao; Bawa, Bhupinder; Liu, Qinfang; Liu, Haixia; Quast, Megan; Sexton, Gabriel; Krammer, Florian; Hause, Ben M.; Christopher-Hennings, Jane; Nelson, Eric A.; Richt, Juergen

    2015-01-01

    ABSTRACT Influenza B virus (IBV) causes seasonal epidemics in humans. Although IBV has been isolated from seals, humans are considered the primary host and reservoir of this important pathogen. It is unclear whether other animal species can support the replication of IBV and serve as a reservoir. Swine are naturally infected with both influenza A and C viruses. To determine the susceptibility of pigs to IBV infection, we conducted a serological survey for U.S. Midwest domestic swine herds from 2010 to 2012. Results of this study showed that antibodies to IBVs were detected in 38.5% (20/52) of sampled farms, and 7.3% (41/560) of tested swine serum samples were positive for IBV antibodies. Furthermore, swine herds infected with porcine reproductive and respiratory syndrome virus (PRRSV) showed a higher prevalence of IBV antibodies in our 2014 survey. In addition, IBV was detected in 3 nasal swabs collected from PRRSV-seropositive pigs by real-time RT-PCR and sequencing. Finally, an experimental infection in pigs, via intranasal and intratracheal routes, was performed using one representative virus from each of the two genetically and antigenically distinct lineages of IBVs: B/Brisbane/60/2008 (Victoria lineage) and B/Yamagata/16/1988 (Yamagata lineage). Pigs developed influenza-like symptoms and lung lesions, and they seroconverted after virus inoculation. Pigs infected with B/Brisbane/60/2008 virus successfully transmitted the virus to sentinel animals. Taken together, our data demonstrate that pigs are susceptible to IBV infection; therefore, they warrant further surveillance and investigation of swine as a potential host for human IBV. IMPORTANCE IBV is an important human pathogen, but its ability to infect other species, for example, pigs, is not well understood. We showed serological evidence that antibodies to two genetically and antigenically distinct lineages of IBVs were present among domestic pigs, especially in swine herds previously infected with PRRSV

  9. Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells

    SciTech Connect

    Redfield, D.C.; Richman, D.D.; Oxman, M.N.; Kronenberg, L.H.

    1981-06-01

    Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays.

  10. Pandemic H1N1 influenza virus infection in a Canadian cat.

    PubMed

    Knight, Cameron G; Davies, Jennifer L; Joseph, Tomy; Ondrich, Sarah; Rosa, Brielle V

    2016-05-01

    A cat was presented for necropsy after being found dead at home. Histologic findings suggested viral pneumonia. Polymerase chain reaction and viral typing revealed influenza A(H1N1)pdm09. This is the first report of influenza in a Canadian cat and highlights the importance of considering influenza virus in the differential diagnosis for feline respiratory distress. PMID:27152036

  11. Evidence for differing evolutionary dynamics of A/H5N1 viruses among countries applying or not applying avian influenza vaccination in poultry.

    PubMed

    Cattoli, Giovanni; Fusaro, Alice; Monne, Isabella; Coven, Fethiye; Joannis, Tony; El-Hamid, Hatem S Abd; Hussein, Aly Ahmed; Cornelius, Claire; Amarin, Nadim Mukhles; Mancin, Marzia; Holmes, Edward C; Capua, Ilaria

    2011-11-21

    Highly pathogenic avian influenza (HPAI) H5N1 (clade 2.2) was introduced into Egypt in early 2006. Despite the control measures taken, including mass vaccination of poultry, the virus rapidly spread among commercial and backyard flocks. Since the initial outbreaks, the virus in Egypt has evolved into a third order clade (clade 2.2.1) and diverged into antigenically and genetically distinct subclades. To better understand the dynamics of HPAI H5N1 evolution in countries that differ in vaccination policy, we undertook an in-depth analysis of those virus strains circulating in Egypt between 2006 and 2010, and compared countries where vaccination was adopted (Egypt and Indonesia) to those where it was not (Nigeria, Turkey and Thailand). This study incorporated 751 sequences (Egypt n=309, Indonesia n=149, Nigeria n=106, Turkey n=87, Thailand n=100) of the complete haemagglutinin (HA) open reading frame, the major antigenic determinant of influenza A virus. Our analysis revealed that two main Egyptian subclades (termed A and B) have co-circulated in domestic poultry since late 2007 and exhibit different profiles of positively selected codons and rates of nucleotide substitution. The mean evolutionary rate of subclade A H5N1 viruses was 4.07×10(-3) nucleotide substitutions per site, per year (HPD 95%, 3.23-4.91), whereas subclade B possessed a markedly higher substitution rate (8.87×10(-3); 95% HPD 7.0-10.72×10(-3)) and a stronger signature of positive selection. Although the direct association between H5N1 vaccination and virus evolution is difficult to establish, we found evidence for a difference in the evolutionary dynamics of H5N1 viruses among countries where vaccination was or was not adopted. In particular, both evolutionary rates and the number of positively selected sites were higher in virus populations circulating in countries applying avian influenza vaccination for H5N1, compared to viruses circulating in countries which had never used vaccination. We

  12. Influenza A virus infection in zebrafish recapitulates mammalian infection and sensitivity to anti-influenza drug treatment.

    PubMed

    Gabor, Kristin A; Goody, Michelle F; Mowel, Walter K; Breitbach, Meghan E; Gratacap, Remi L; Witten, P Eckhard; Kim, Carol H

    2014-11-01

    Seasonal influenza virus infections cause annual epidemics and sporadic pandemics. These present a global health concern, resulting in substantial morbidity, mortality and economic burdens. Prevention and treatment of influenza illness is difficult due to the high mutation rate of the virus, the emergence of new virus strains and increasing antiviral resistance. Animal models of influenza infection are crucial to our gaining a better understanding of the pathogenesis of and host response to influenza infection, and for screening antiviral compounds. However, the current animal models used for influenza research are not amenable to visualization of host-pathogen interactions or high-throughput drug screening. The zebrafish is widely recognized as a valuable model system for infectious disease research and therapeutic drug testing. Here, we describe a zebrafish model for human influenza A virus (IAV) infection and show that zebrafish embryos are susceptible to challenge with both influenza A strains APR8 and X-31 (Aichi). Influenza-infected zebrafish show an increase in viral burden and mortality over time. The expression of innate antiviral genes, the gross pathology and the histopathology in infected zebrafish recapitulate clinical symptoms of influenza infections in humans. This is the first time that zebrafish embryos have been infected with a fluorescent IAV in order to visualize infection in a live vertebrate host, revealing a pattern of vascular endothelial infection. Treatment of infected zebrafish with a known anti-influenza compound, Zanamivir, reduced mortality and the expression of a fluorescent viral gene product, demonstrating the validity of this model to screen for potential antiviral drugs. The zebrafish model system has provided invaluable insights into host-pathogen interactions for a range of infectious diseases. Here, we demonstrate a novel use of this species for IAV research. This model has great potential to advance our understanding of

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  14. A two-amino acid substitution in the 1918 influenza virus hemagglutinin abolishes transmission of the pandemic virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 1918 influenza pandemic was a catastrophic series of virus outbreaks that spread across the globe. Herein we show that only a modest change in the 1918 influenza hemagglutinin receptor binding site alters the transmissibility of this pandemic virus. Two amino acid mutations that cause a switch f...

  15. Drug Repurposing Identifies Inhibitors of Oseltamivir-Resistant Influenza Viruses.

    PubMed

    Bao, Ju; Marathe, Bindumadhav; Govorkova, Elena A; Zheng, Jie J

    2016-03-01

    The neuraminidase (NA) inhibitor, oseltamivir, is a widely used anti-influenza drug. However, oseltamivir-resistant H1N1 influenza viruses carrying the H275Y NA mutation spontaneously emerged as a result of natural genetic drift and drug treatment. Because H275Y and other potential mutations may generate a future pandemic influenza strain that is oseltamivir-resistant, alternative therapy options are needed. Herein, we show that a structure-based computational method can be used to identify existing drugs that inhibit resistant viruses, thereby providing a first line of pharmaceutical defense against this possible scenario. We identified two drugs, nalidixic acid and dorzolamide, that potently inhibit the NA activity of oseltamivir-resistant H1N1 viruses with the H275Y NA mutation at very low concentrations, but have no effect on wild-type H1N1 NA even at a much higher concentration, suggesting that the oseltamivir-resistance mutation itself caused susceptibility to these drugs. PMID:26833677

  16. Oral Administration of a Prodrug of the Influenza Virus Neuraminidase Inhibitor GS 4071 Protects Mice and Ferrets against Influenza Infection

    PubMed Central

    Mendel, Dirk B.; Tai, Chun Y.; Escarpe, Paul A.; Li, Weixing; Sidwell, Robert W.; Huffman, John H.; Sweet, Clive; Jakeman, Kenneth J.; Merson, James; Lacy, Steven A.; Lew, Willard; Williams, Matthew A.; Zhang, Lijun; Chen, Ming S.; Bischofberger, Norbert; Kim, Choung U.

    1998-01-01

    We have recently described GS 4071, a carbocyclic transition-state analog inhibitor of the influenza virus neuraminidase, which has potent inhibitory activity comparable to that of 4-guanidino-Neu5Ac2en (GG167; zanamivir) when tested against influenza A virus replication and neuraminidase activity in vitro. We now report that GS 4071 is active against several strains of influenza A and B viruses in vitro and that oral GS 4104, an ethyl ester prodrug which is converted to GS 4071 in vivo, is active in the mouse and ferret models of influenza virus infection. Oral administration of 10 mg of GS 4104 per kg of body weight per day caused a 100-fold reduction in lung homogenate viral titers and enhanced survival in mice infected with influenza A or B viruses. In ferrets, a 25-mg/kg dose of GS 4104 given twice daily reduced peak viral titers in nasal washings and eliminated constitutional responses to influenza virus infection including fever, increased nasal signs (sneezing, nasal discharge, mouth breathing), and decreased activity. Consistent with our demonstration that the parent compound is highly specific for influenza virus neuraminidases, no significant drug-related toxicity was observed after the administration of oral dosages of GS 4104 of up to 800 mg/kg/day for 14 days in nonclinical toxicology studies with rats. These results indicate that GS 4104 is a novel, orally active antiviral agent with the potential to be used for the prophylaxis and treatment of influenza A and B virus infections. PMID:9517945

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

    PubMed

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

    2016-01-01

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

  18. Soluble Host Defense Lectins in Innate Immunity to Influenza Virus

    PubMed Central

    Ng, Wy Ching; Tate, Michelle D.; Brooks, Andrew G.; Reading, Patrick C.

    2012-01-01

    Host defenses against viral infections depend on a complex interplay of innate (nonspecific) and adaptive (specific) components. In the early stages of infection, innate mechanisms represent the main line of host defense, acting to limit the spread of virus in host tissues prior to the induction of the adaptive immune response. Serum and lung fluids contain a range of lectins capable of recognizing and destroying influenza A viruses (IAV). Herein, we review the mechanisms by which soluble endogenous lectins mediate anti-IAV activity, including their role in modulating IAV-induced inflammation and disease and their potential as prophylactic and/or therapeutic treatments during severe IAV-induced disease. PMID:22665991

  19. Newcastle disease virus detection and differentiation from avian influenza.

    PubMed

    Miller, Patti J; Torchetti, Mia Kim

    2014-01-01

    Newcastle disease (ND) is a contagious and often fatal disease that affects over 250 bird species worldwide, and is caused by infection with virulent strains of avian paramyxovirus-1 (APMV-1) of the family Paramyxoviridae, genus Avulavirus. Infections of poultry with virulent strains of APMV-1 (Newcastle disease virus) are reportable to the World Organization for Animal Health (OIE). Vaccination of poultry species is a key measure in the control of ND. Other APMV-1 viruses of low virulence, which are not used as vaccines, are also often isolated from wild bird species. The APMV-1 virus, like avian influenza virus (AIV), is a hemagglutinating virus (HA) and able to agglutinate chicken red blood cells (RBC). Because the clinical presentation of ND can be difficult to distinguish from disease caused by AIV, techniques for differential diagnosis are essential, as well as the ability to detect mixed infections. When an HA positive virus is detected from virus isolation, additional assays can be performed to determine which virus is present. Both antigenic and molecular methods are necessary as some virulent ND viruses from cormorants in the USA after 2002 have lost their ability to hemagglutinate chicken RBC and molecular methods are needed for identification. PMID:24899433

  20. Canada geese and the epidemiology of avian influenza viruses.

    PubMed

    Harris, Mark T; Brown, Justin D; Goekjian, Virginia H; Luttrell, M Page; Poulson, Rebecca L; Wilcox, Benjamin R; Swayne, David E; Stallknecht, David E

    2010-07-01

    Canada geese (Branta canadensis) are numerous, highly visible, and widely distributed in both migratory and resident populations in North America; as a member of the order Anseriformes, they are often suggested as a potential reservoir and source for avian influenza (AI) viruses. To further examine the role of Canada Geese in the ecology of AI, we re-evaluated existing literature related to AI virus in this species and tested breeding populations of Canada Geese from three states (Georgia, West Virginia, and Minnesota, USA) by virus isolation and serology. The ability of AI virus to persist in goose feces under experimental conditions also was evaluated as an additional measure of the potential for this species to serve as an AI virus reservoir. Virus was not isolated from 1,668 cloacal swabs and type-specific antibody prevalence was low (4/335, 1.2%). Finally, under experimental conditions, AI virus persistence in goose feces and in water contaminated with goose feces was limited as compared to published estimates from duck feces and water. Our results are consistent with historic reports of a low prevalence of AI virus infection in this species, and we suggest that Canada Geese play a minor, if any, role as a reservoir for low pathogenic AI viruses that naturally circulate in wild bird populations. PMID:20688710

  1. Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine

    PubMed Central

    Deng, Yi‐Mo; Iannello, Pina; Smith, Ina; Watson, James; Barr, Ian G.; Daniels, Peter; Komadina, Naomi; Harrower, Bruce; Wong, Frank Y. K.

    2012-01-01

    Please cite this paper as: Deng et al. (2012). Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine. Influenza and Other Respiratory Viruses 6(3), e42–e47. Background  Swine have receptors for both human and avian influenza viruses and are a natural host for influenza A viruses. The 2009 influenza A(H1N1) pandemic (H1N1pdm) virus that was derived from avian, human and swine influenza viruses has infected pigs in various countries. Objectives  To investigate the relationship between the H1N1pdm viruses isolated from piggery outbreaks in Australia and human samples associated with one of the outbreaks by phylogenetic analysis, and to determine whether there was any reassortment event occurring during the human‐pig interspecies transmission. Methods  Real‐time RT‐PCR and full genome sequencing were carried out on RNA isolated from nasal swabs and/or virus cultures. Phylogenetic analysis was performed using the Geneious package. Results  The influenza H1N1pdm outbreaks were detected in three pig farms located in three different states in Australia. Further analysis of the Queensland outbreak led to the identification of two distinct virus strains in the pigs. Two staff working in the same piggery were also infected with the same two strains found in the pigs. Full genome sequence analysis on the viruses isolated from pigs and humans did not identify any reassortment of these H1N1pdm viruses with seasonal or avian influenza A viruses. Conclusions  This is the first report of swine infected with influenza in Australia and marked the end of the influenza‐free era for the Australian swine industry. Although no reassortment was detected in these cases, the ability of these viruses to cross between pigs and humans highlights the importance of monitoring swine for novel influenza infections. PMID:22336333

  2. Virulence and Genetic Compatibility of Polymerase Reassortant Viruses Derived from the Pandemic (H1N1) 2009 Influenza Virus and Circulating Influenza A Viruses▿†

    PubMed Central

    Song, Min-Suk; Pascua, Philippe Noriel Q.; Lee, Jun Han; Baek, Yun Hee; Park, Kuk Jin; Kwon, Hyeok-il; Park, Su-Jin; Kim, Chul-Joong; Kim, Hyunggee; Webby, Richard J.; Webster, Robert G.; Choi, Young Ki

    2011-01-01

    Gene mutations and reassortment are key mechanisms by which influenza A virus acquires virulence factors. To evaluate the role of the viral polymerase replication machinery in producing virulent pandemic (H1N1) 2009 influenza viruses, we generated various polymerase point mutants (PB2, 627K/701N; PB1, expression of PB1-F2 protein; and PA, 97I) and reassortant viruses with various sources of influenza viruses by reverse genetics. Although the point mutations produced no significant change in pathogenicity, reassortment between the pandemic A/California/04/09 (CA04, H1N1) and current human and animal influenza viruses produced variants possessing a broad spectrum of pathogenicity in the mouse model. Although most polymerase reassortants had attenuated pathogenicity (including those containing seasonal human H3N2 and high-pathogenicity H5N1 virus segments) compared to that of the parental CA04 (H1N1) virus, some recombinants had significantly enhanced virulence. Unexpectedly, one of the five highly virulent reassortants contained a A/Swine/Korea/JNS06/04(H3N2)-like PB2 gene with no known virulence factors; the other four had mammalian-passaged avian-like genes encoding PB2 featuring 627K, PA featuring 97I, or both. Overall, the reassorted polymerase complexes were only moderately compatible for virus rescue, probably because of disrupted molecular interactions involving viral or host proteins. Although we observed close cooperation between PB2 and PB1 from similar virus origins, we found that PA appears to be crucial in maintaining viral gene functions in the context of the CA04 (H1N1) virus. These observations provide helpful insights into the pathogenic potential of reassortant influenza viruses composed of the pandemic (H1N1) 2009 influenza virus and prevailing human or animal influenza viruses that could emerge in the future. PMID:21507962

  3. Antiviral drug susceptibilities of seasonal human influenza viruses in Lebanon, 2008-09 season.

    PubMed

    Zaraket, Hassan; Saito, Reiko; Wakim, Rima; Tabet, Carelle; Medlej, Fouad; Reda, Mariam; Baranovich, Tatiana; Suzuki, Yasushi; Dapat, Clyde; Caperig-Dapat, Isolde; Dbaibo, Ghassan S; Suzuki, Hiroshi

    2010-07-01

    The emergence of antiviral drug-resistant strains of the influenza virus in addition to the rapid spread of the recent pandemic A(H1N1) 2009 virus highlight the importance of surveillance of influenza in identifying new variants as they appear. In this study, genetic characteristics and antiviral susceptibility patterns of influenza samples collected in Lebanon during the 2008-09 season were investigated. Forty influenza virus samples were isolated from 89 nasopharyngeal swabs obtained from patients with influenza-like illness. Of these samples, 33 (82.5%) were A(H3N2), 3 (7.5%) were A(H1N1), and 4 (10%) were B. All the H3N2 viruses were resistant to amantadine but were sensitive to oseltamivir and zanamivir; while all the H1N1 viruses were resistant to oseltamivir (possessed H275Y mutation, N1 numbering, in their NA) but were sensitive to amantadine and zanamivir. In the case of influenza B, both Victoria and Yamagata lineages were identified (three and one isolates each, respectively) and they showed decreased susceptibility to oseltamivir and zanamivir when compared to influenza A viruses. Influenza circulation patterns in Lebanon were very similar to those in Europe during the same season. Continued surveillance is important to fully elucidate influenza patterns in Lebanon and the Middle East in general, especially in light of the current influenza pandemic. PMID:20513088

  4. Influenza in Migratory Birds and Evidence of Limited Intercontinental Virus Exchange

    PubMed Central

    Krauss, Scott; Obert, Caroline A; Franks, John; Walker, David; Jones, Kelly; Seiler, Patrick; Niles, Larry; Pryor, S. Paul; Obenauer, John C; Naeve, Clayton W; Widjaja, Linda; Webby, Richard J; Webster, Robert G

    2007-01-01

    Migratory waterfowl of the world are the natural reservoirs of influenza viruses of all known subtypes. However, it is unknown whether these waterfowl perpetuate highly pathogenic (HP) H5 and H7 avian influenza viruses. Here we report influenza virus surveillance from 2001 to 2006 in wild ducks in Alberta, Canada, and in shorebirds and gulls at Delaware Bay (New Jersey), United States, and examine the frequency of exchange of influenza viruses between the Eurasian and American virus clades, or superfamilies. Influenza viruses belonging to each of the subtypes H1 through H13 and N1 through N9 were detected in these waterfowl, but H14 and H15 were not found. Viruses of the HP Asian H5N1 subtypes were not detected, and serologic studies in adult mallard ducks provided no evidence of their circulation. The recently described H16 subtype of influenza viruses was detected in American shorebirds and gulls but not in ducks. We also found an unusual cluster of H7N3 influenza viruses in shorebirds and gulls that was able to replicate well in chickens and kill chicken embryos. Genetic analysis of 6,767 avian influenza gene segments and 248 complete avian influenza viruses supported the notion that the exchange of entire influenza viruses between the Eurasian and American clades does not occur frequently. Overall, the available evidence does not support the perpetuation of HP H5N1 influenza in migratory birds and suggests that the introduction of HP Asian H5N1 to the Americas by migratory birds is likely to be a rare event. PMID:17997603

  5. Nanomicroarray and Multiplex Next-Generation Sequencing for Simultaneous Identification and Characterization of Influenza Viruses

    PubMed Central

    Ragupathy, Viswanath; Liu, Jikun; Wang, Xue; Vemula, Sai Vikram; El Mubarak, Haja Sittana; Ye, Zhiping; Landry, Marie L.

    2015-01-01

    Conventional methods for detection and discrimination of influenza viruses are time consuming and labor intensive. We developed a diagnostic platform for simultaneous identification and characterization of influenza viruses that uses a combination of nanomicroarray for screening and multiplex next-generation sequencing (NGS) assays for laboratory confirmation. The nanomicroarray was developed to target hemagglutinin, neuraminidase, and matrix genes to identify influenza A and B viruses. PCR amplicons synthesized by using an adapted universal primer for all 8 gene segments of 9 influenza A subtypes were detected in the nanomicroarray and confirmed by the NGS assays. This platform can simultaneously detect and differentiate multiple influenza A subtypes in a single sample. Use of these methods as part of a new diagnostic algorithm for detection and confirmation of influenza infections may provide ongoing public health benefits by assisting with future epidemiologic studies and improving preparedness for potential influenza pandemics. PMID:25694248

  6. Early apoptosis of porcine alveolar macrophages limits avian influenza virus replication and pro-inflammatory dysregulation

    PubMed Central

    Chang, Pengxiang; Kuchipudi, Suresh V.; Mellits, Kenneth H.; Sebastian, Sujith; James, Joe; Liu, Jinhua; Shelton, Holly; Chang, Kin-Chow

    2015-01-01

    Pigs are evidently more resistant to avian than swine influenza A viruses, mediated in part through frontline epithelial cells and alveolar macrophages (AM). Although porcine AM (PAM) are crucial in influenza virus control, their mode of control is unclear. To gain insight into the possible role of PAM in the mediation of avian influenza virus resistance, we compared the host effects and replication of two avian (H2N3 and H6N1) and three mammalian (swine H1N1, human H1N1 and pandemic H1N1) influenza viruses in PAM. We found that PAM were readily susceptible to initial infection with all five avian and mammalian influenza viruses but only avian viruses caused early and extensive apoptosis (by 6 h of infection) resulting in reduced virus progeny and moderated pro-inflammation. Full length viral PB1-F2 present only in avian influenza viruses is a virulence factor that targets AM for mitochondrial-associated apoptotic cell death. With the use of reverse genetics on an avian H5N1 virus, we found that full length PB1-F2 contributed to increased apoptosis and pro-inflammation but not to reduced virus replication. Taken together, we propose that early apoptosis of PAM limits the spread of avian influenza viruses and that PB1-F2 could play a contributory role in the process. PMID:26642934

  7. Early apoptosis of porcine alveolar macrophages limits avian influenza virus replication and pro-inflammatory dysregulation.

    PubMed

    Chang, Pengxiang; Kuchipudi, Suresh V; Mellits, Kenneth H; Sebastian, Sujith; James, Joe; Liu, Jinhua; Shelton, Holly; Chang, Kin-Chow

    2015-01-01

    Pigs are evidently more resistant to avian than swine influenza A viruses, mediated in part through frontline epithelial cells and alveolar macrophages (AM). Although porcine AM (PAM) are crucial in influenza virus control, their mode of control is unclear. To gain insight into the possible role of PAM in the mediation of avian influenza virus resistance, we compared the host effects and replication of two avian (H2N3 and H6N1) and three mammalian (swine H1N1, human H1N1 and pandemic H1N1) influenza viruses in PAM. We found that PAM were readily susceptible to initial infection with all five avian and mammalian influenza viruses but only avian viruses caused early and extensive apoptosis (by 6 h of infection) resulting in reduced virus progeny and moderated pro-inflammation. Full length viral PB1-F2 present only in avian influenza viruses is a virulence factor that targets AM for mitochondrial-associated apoptotic cell death. With the use of reverse genetics on an avian H5N1 virus, we found that full length PB1-F2 contributed to increased apoptosis and pro-inflammation but not to reduced virus replication. Taken together, we propose that early apoptosis of PAM limits the spread of avian influenza viruses and that PB1-F2 could play a contributory role in the process. PMID:26642934

  8. Oseltamivir inhibits influenza virus replication and transmission following ocular-only aerosol inoculation of ferrets.

    PubMed

    Belser, Jessica A; Maines, Taronna R; Creager, Hannah M; Katz, Jacqueline M; Tumpey, Terrence M

    2015-10-01

    Ocular exposure to influenza virus represents an alternate route of virus entry capable of establishing a respiratory infection in mammals, but the effectiveness of currently available antiviral treatments to limit virus replication within ocular tissue or inhibit virus spread from ocular sites to the respiratory tract is poorly understood. Using an inoculation method that delivers an aerosol inoculum exclusively to the ocular surface, we demonstrate that oral oseltamivir administration following ocular-only aerosol inoculation with multiple avian and human influenza viruses protected ferrets from a fatal and systemic infection, reduced clinical signs and symptoms of illness, and decreased virus transmissibility to susceptible contacts when a respiratory infection was initiated. The presence of oseltamivir further inhibited influenza virus replication in primary human corneal epithelial cells. These findings provide critical experimental evidence supporting the use of neuraminidase inhibitors during outbreaks of influenza virus resulting in ocular disease or following ocular exposure. PMID:26142497

  9. Detailed Report on 2014/15 Influenza Virus Characteristics, and Estimates on Influenza Virus Vaccine Effectiveness from Austria’s Sentinel Physician Surveillance Network

    PubMed Central

    2016-01-01

    Background Influenza vaccine effectiveness (VE) is influenced by the antigenic similarity between vaccine- and circulating strains. Material and Methods This paper presents data obtained by the Austrian sentinel surveillance system on the evolution of influenza viruses during the season 2014/15 and its impact on influenza vaccine effectiveness in primary care in Austria as estimated by a test-negative case control design. VE estimates were performed for each influenza virus type/subtype, stratified by underlying diseases and adjusted for age, sex and calendar week of infection. Results Detailed genetic and antigenic analyses showed that circulating A(H3N2) viruses were genetically distinct from the 2014/15 A(H3N2) vaccine component indicating a profound vaccine mismatch. The Influenza A(H1N1)pdm09 viruses were antigenically conserved and matched the respective vaccine component. Influenza B viruses were lineage-matched B/Yamagata viruses with a clade-level variation. Consistent with substantial vaccine mismatch for the A(H3N2) viruses a crude overall VE of only 47% was estimated, whereas the VE estimates for A(H1N1)pdm09 were 84% and for influenza B viruses 70%. Increased VE estimates were obtained after stratification by underlying diseases and adjustment for the covariates sex and age, whereby the adjustment for the calendar week of infection was the covariate exerting the highest influence on adjusted VE estimates. Conclusion In summary, VE data obtained in this study underscore the importance to perform VE estimates in the context of detailed characterization of the contributing viruses and also demonstrate that the calendar week of influenza virus infection is the most important confounder of VE estimates. PMID:26975056

  10. A Complete Molecular Diagnostic Procedure for Applications in Surveillance and Subtyping of Avian Influenza Virus

    PubMed Central

    Tseng, Chun-Hsien; Tsai, Hsiang-Jung; Chang, Chung-Ming

    2014-01-01

    Introduction. The following complete molecular diagnostic procedure we developed, based on real-time quantitative PCR and traditional PCR, is effective for avian influenza surveillance, virus subtyping, and viral genome sequencing. Method. This study provides a specific and sensitive step-by-step procedure for efficient avian influenza identification of 16 hemagglutinin and 9 neuraminidase avian influenza subtypes. Result and Conclusion. This diagnostic procedure may prove exceedingly useful for virological and ecological advancements in global avian influenza research. PMID:25057497

  11. Heightened adaptive immune responses following vaccination with a temperature-sensitive, live-attenuated influenza virus compared to adjuvanted, whole-inactivated virus in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States there are currently two influenza vaccine platforms approved for use in humans - conventional inactivated virus and live-attenuated influenza virus (LAIV). One of the major challenges for influenza A virus (IAV) vaccination is designing a platform that provides protection across...

  12. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses

    PubMed Central

    Holm, Christian K.; Rahbek, Stine H.; Gad, Hans Henrik; Bak, Rasmus O.; Jakobsen, Martin R.; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K.; Sun, Chenglong; Thomsen, Martin K.; Laustsen, Anders; Nielsen, Camilla G.; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L.; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A.; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R.

    2016-01-01

    Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV. PMID:26893169

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

    PubMed Central

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

    2013-01-01

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

  14. 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

  15. Superior In Vitro Stimulation of Human CD8+ T-Cells by Whole Virus versus Split Virus Influenza Vaccines

    PubMed Central

    Distler, Eva; Dass, Martin; Wagner, Eva M.; Plachter, Bodo; Probst, Hans Christian; Strand, Dennis; Hartwig, Udo F.; Karner, Anita; Aichinger, Gerald; Kistner, Otfried; Landfester, Katharina; Herr, Wolfgang

    2014-01-01

    Pandemic and seasonal influenza viruses cause considerable morbidity and mortality in the general human population. Protection from severe disease may result from vaccines that activate antigen-presenting DC for effective stimulation of influenza-specific memory T cells. Special attention is paid to vaccine-induced CD8+ T-cell responses, because they are mainly directed against conserved internal influenza proteins thereby presumably mediating cross-protection against circulating seasonal as well as emerging pandemic virus strains. Our study showed that influenza whole virus vaccines of major seasonal A and B strains activated DC more efficiently than those of pandemic swine-origin H1N1 and pandemic-like avian H5N1 strains. In contrast, influenza split virus vaccines had a low ability to activate DC, regardless which strain was investigated. We also observed that whole virus vaccines stimulated virus-specific CD8+ memory T cells much stronger compared to split virus counterparts, whereas both vaccine formats activated CD4+ Th cell responses similarly. Moreover, our data showed that whole virus vaccine material is delivered into the cytosolic pathway of DC for effective activation of virus-specific CD8+ T cells. We conclude that vaccines against seasonal and pandemic (-like) influenza strains that aim to stimulate cross-reacting CD8+ T cells should include whole virus rather than split virus formulations. PMID:25072749

  16. Virological Surveillance of Influenza Viruses during the 2008–09, 2009–10 and 2010–11 Seasons in Tunisia

    PubMed Central

    El Moussi, Awatef; Pozo, Francisco; Ben Hadj Kacem, Mohamed Ali; Ledesma, Juan; Cuevas, Maria Teresa; Casas, Inmaculada; Slim, Amine

    2013-01-01

    Background The data contribute to a better understanding of the circulation of influenza viruses especially in North-Africa. Objective The objective of this surveillance was to detect severe influenza cases, identify their epidemiological and virological characteristics and assess their impact on the healthcare system. Method We describe in this report the findings of laboratory-based surveillance of human cases of influenza virus and other respiratory viruses' infection during three seasons in Tunisia. Results The 2008–09 winter influenza season is underway in Tunisia, with co-circulation of influenza A/H3N2 (56.25%), influenza A(H1N1) (32.5%), and a few sporadic influenza B viruses (11.25%). In 2010–11 season the circulating strains are predominantly the 2009 pandemic influenza A(H1N1)pdm09 (70%) and influenza B viruses (22%). And sporadic viruses were sub-typed as A/H3N2 and unsubtyped influenza A, 5% and 3%, respectively. Unlike other countries, highest prevalence of influenza B virus Yamagata-like lineage has been reported in Tunisia (76%) localised into the clade B/Bangladesh/3333/2007. In the pandemic year, influenza A(H1N1)pdm09 predominated over other influenza viruses (95%). Amino acid changes D222G and D222E were detected in the HA gene of A(H1N1)pdm09 virus in two severe cases, one fatal case and one mild case out of 50 influenza A(H1N1)pdm09 viruses studied. The most frequently reported respiratory virus other than influenza in three seasons was RSV (45.29%). Conclusion This article summarises the surveillance and epidemiology of influenza viruses and other respiratory viruses, showing how rapid improvements in influenza surveillance were feasible by connecting the existing structure in the health care system for patient records to electronic surveillance system for reporting ILI cases. PMID:24069267

  17. Within-host variation of avian influenza viruses

    PubMed Central

    Iqbal, Munir; Xiao, Hiaxia; Baillie, Greg; Warry, Andrew; Essen, Steve C.; Londt, Brandon; Brookes, Sharon M.; Brown, Ian H.; McCauley, John W.

    2009-01-01

    The emergence and spread of H5N1 avian influenza viruses from Asia through to Europe and Africa pose a significant animal disease problem and have raised concerns that the virus may pose a pandemic threat to humans. The epizootological factors that have influenced the wide distribution of the virus are complex, and the variety of viruses currently circulating reflects these factors. Sequence analysis of the virus genes sheds light on the H5N1 virus evolution during its emergence and spread, but the degree of virus variation at the level of an individual infected bird has been described in only a few studies. Here, we describe some results of a study in which turkeys, ducks and chickens were infected with either one of two H5N1 or one of three H7N1 viruses, and the degree of sequence variation within an individual infected avian host was examined. We developed ‘deep amplicon’ sequence analysis for this work, and the methods and results provide a background framework for application to disease outbreaks in the field. PMID:19687042

  18. Regulatory effects of matrix protein variations on influenza virus growth.

    PubMed

    Yasuda, J; Toyoda, T; Nakayama, M; Ishihama, A

    1993-01-01

    Influenza virus A/WSN/33 forms large plaques (> 3 mm diameter) on MDCK cells whereas A/Aichi/2/68 forms only small plaques (< 1 mm diameter). Fast growing reassortants (AWM), isolated by mixed infection of MDCK cells with these two virus strains in the presence of anti-WSN antibodies, all carried the M gene from WSN. On MDCK cells, these reassortants produced progeny viruses as rapidly as did WSN, and the virus yield was as high as Aichi. The fast-growing reassortants overcame the growth inhibitory effect of lignins. Pulse-labeling experiments at various times after virus infection showed that the reassortant AWM started to synthesize viral proteins earlier than Aichi. Taken together, we conclude that upon infecting MDCK cells, the reassortant viruses advance rapidly into the growth cycle, thereby leading to an elevated level of progeny viruses in the early period of infection. Possible mechanisms of the M gene involvement in the determination of virus growth rate are discussed, in connection with multiple functions of the M proteins. PMID:8257290

  19. Adaptation of pandemic H2N2 influenza A viruses in humans.

    PubMed

    Joseph, Udayan; Linster, Martin; Suzuki, Yuka; Krauss, Scott; Halpin, Rebecca A; Vijaykrishna, Dhanasekaran; Fabrizio, Thomas P; Bestebroer, Theo M; Maurer-Stroh, Sebastian; Webby, Richard J; Wentworth, David E; Fouchier, Ron A M; Bahl, Justin; Smith, Gavin J D

    2015-02-01

    The 1957 A/H2N2 influenza virus caused an estimated 2 million fatalities during the pandemic. Since viruses of the H2 subtype continue to infect avian species and pigs, the threat of reintroduction into humans remains. To determine factors involved in the zoonotic origin of the 1957 pandemic, we performed analyses on genetic sequences of 175 newly sequenced human and avian H2N2 virus isolates and all publicly available influenza virus genomes. PMID:25505070

  20. Highly pathogenic avian influenza viruses and generation of novel reassortants,United States, 2014–2015

    USGS Publications Warehouse

    Dong-Hun Lee; Justin Bahl; Mia Kim Torchetti; Mary Lea Killian; Ip, Hon S.; David E Swayne

    2016-01-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses.

  1. Serological studies of influenza viruses in pigs in Great Britain 1991-2.

    PubMed

    Brown, I H; Harris, P A; Alexander, D J

    1995-06-01

    Samples from a sow serum bank representative of the pig population of Great Britain collected during 1991-2, were examined for antibodies to influenza A, B and C viruses, using viruses which had been isolated from a variety of hosts. For influenza A viruses there was evidence of the continued circulation of classical swine H1N1 virus (26%) seroprevalence), and human H3N2 viruses (39%) which are antigenically most closely-related to A/Port Chalmers/1/73 virus. In addition antibodies were detected to A/swine/England/201635/92 (8%), a strain of H3N2 virus which appears to have arisen by antigenic drift from conventional H3N2 swine strains. Specific antibodies (2%) were detected to an H1N1 virus (A/swine/England/195852/92) related most closely to avian H1N1 strains. In tests with human H1N1 and H3N2 viruses, excluding isolates from pigs, the highest seroprevalence was detected to the prevailing strains from the human population. Serological tests with avian H4 and H10, human H2, equine 1 and 2 influenza A viruses were all negative. Seven pigs seropositive by haemagglutination-inhibition, virus neutralization and immunoblotting assays for antibody to influenza B virus, were randomly distributed geographically suggesting that influenza B viruses may be transmitted to pigs but fail to spread. The seroprevalence to influenza C viruses was 9.9% indicating that these viruses are widespread in pigs. These results provide further evidence that the pig can be infected by a number of influenza viruses, some of which may have significance in the epidemiology of human influenza. PMID:7781739

  2. 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. PMID:18680652

  3. Highly Pathogenic Avian Influenza Viruses and Generation of Novel Reassortants, United States, 2014–2015

    PubMed Central

    Lee, Dong-Hun; Bahl, Justin; Torchetti, Mia Kim; Killian, Mary Lea; Ip, Hon S.; DeLiberto, Thomas J.

    2016-01-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses. PMID:27314845

  4. Investigating Influenza A Virus Infection: Tools To Track Infection and Limit Tropism

    PubMed Central

    Fiege, Jessica K.

    2015-01-01

    Influenza A viruses display a broad cellular tropism within the respiratory tracts of mammalian hosts. Uncovering the relationship between tropism and virus immunity, pathogenesis, and transmission will be critical for the development of therapeutic interventions. Here we discuss recent developments of several recombinant strains of influenza A virus. These viruses have inserted reporters to track tropism, microRNA target sites to restrict tropism, or barcodes to assess transmission dynamics, expanding our understanding of pathogen-host interactions. PMID:25855737

  5. Highly Pathogenic Avian Influenza Viruses and Generation of Novel Reassortants, United States, 2014-2015.

    PubMed

    Lee, Dong-Hun; Bahl, Justin; Torchetti, Mia Kim; Killian, Mary Lea; Ip, Hon S; DeLiberto, Thomas J; Swayne, David E

    2016-07-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses. PMID:27314845

  6. Refining the approach to vaccines against influenza A viruses with pandemic potential

    PubMed Central

    Czako, Rita; Subbarao, Kanta

    2015-01-01

    Vaccination is the most effective strategy for prevention and control of influenza. Timely production and deployment of seasonal influenza vaccines is based on an understanding of the epidemiology of influenza and on global disease and virologic surveillance. Experience with seasonal influenza vaccines guided the initial development of pandemic influenza vaccines. A large investment in pandemic influenza vaccines in the last decade has resulted in much progress and a body of information that can now be applied to refine the established paradigm. Critical and complementary considerations for pandemic influenza vaccines include improved assessment of the pandemic potential of animal influenza viruses, proactive development and deployment of pandemic influenza vaccines, and application of novel platforms and strategies for vaccine production and administration. PMID:26587050

  7. Recombinant Hemagglutinin and Virus-Like Particle Vaccines for H7N9 Influenza Virus

    PubMed Central

    Li, Xiaohui; Pushko, Peter; Tretyakova, Irina

    2015-01-01

    Cases of H7N9 human infection were caused by a novel, avian-origin H7N9 influenza A virus that emerged in eastern China in 2013. Clusters of human disease were identified in many cities in China, with mortality rates approaching 30%. Pandemic concerns were raised, as historically, influenza pandemics were caused by introduction of novel influenza A viruses into immunologically naïve human population. Currently, there are no approved human vaccines for H7N9 viruses. Recombinant protein vaccine approaches have advantages in safety and manufacturing. In this review, we focused on evaluation of the expression of recombinant hemagglutinin (rHA) proteins as candidate vaccines for H7N9 influenza, with the emphasis on the role of oligomeric and particulate structures in immunogenicity and protection. Challenges in preparation of broadly protective influenza vaccines are discussed, and examples of broadly protective vaccines are presented including rHA stem epitope vaccines, as well as recently introduced experimental multi-HA VLP vaccines. PMID:26523241

  8. Influenza A virus infections in land birds, People's Republic of China

    USGS Publications Warehouse

    Peterson, A.T.; Bush, S.E.; Spackman, Erica; Swayne, D.E.; Ip, H.S.

    2008-01-01

    Water birds are considered the reservoir for avian influenza viruses. We examined this assumption by sampling and real-time reverse transcription-PCR testing of 939 Asian land birds of 153 species. Influenza A infection was found, particularly among migratory species. Surveillance programs for monitoring spread of these viruses need to be redesigned.

  9. Immune mechanisms associated with enhanced influenza A virus disease versus cross-protection in vaccinated pigs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine associated enhanced respiratory disease (VAERD) has been described in pigs vaccinated with whole-inactivated influenza virus (WIV) following infection with heterologous influenza A virus (IAV). WIV vaccination elicits production of cross-reactive, non-neutralizing antibody to the challenge I...

  10. Absence of Pandemic H1N1 Influenza A Virus in Fresh Pork

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pigs experimentally infected with pandemic 2009 H1N1 influenza A virus developed respiratory disease; however, there was no evidence for systemic disease to suggest that pork from pigs infected with H1N1 influenza would contain infectious virus. These findings support the WHO recommendation that po...

  11. Mucosal correlates of cross-protection for live-attenuated influenza virus vaccines in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlling swine influenza A virus (IAV) has become increasingly difficult with the emergence of novel reassorted strains and introduction of human seasonal IAV into pigs. In North American swine there are 6 antigenically distinct H1 subtypes currently circulating. Live-attenuated influenza virus (...

  12. Pathobiology of Asian highly pathogenic avian influenza H5N1 virus infection in ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ducks and other wild aquatic birds are the natural reservoir of influenza type A viruses which normally are nonpathogenic in these birds. However, the Asian H5N1 avian influenza (AI) viruses have evolved from producing no disease or mild respiratory infections in ducks, to some strains producing se...

  13. Susceptibility of avian species to north american H13 low pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gulls are widely recognized reservoirs for low pathogenic avian influenza (LPAI) viruses; however, the subtypes maintained in these populations and/or the transmission mechanisms involved are poorly understood. Although, a wide diversity of influenza viruses have been isolated from gulls, two hemag...

  14. Comparative susceptibility of avian species to low pathogenic avian influenza viruses of the H13 subtype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gulls are widely recognized reservoirs for low pathogenic avian influenza (LPAI) viruses; however, the subtypes maintained in these populations and/or the transmission mechanisms involved are poorly understood. Although, a wide diversity of influenza viruses have been isolated from gulls, two hemag...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. ATTENUATION OF AN H3N2 SWINE INFLUENZA VIRUS UTILIZING A REVERSE GENETICS APPROACH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine influenza (SI) is an acute respiratory disease of swine caused by type A influenza viruses. Before 1998, mainly Aclassical@ H1N1 SI viruses (SIV) were isolated from swine in the United States. Since then, antigenetically distinct reassortant H1 and H3 SIVs have been identified as causative ag...

  17. Lymphocyte responses in the lungs of vaccinated pigs following homologous and heterologous influenza A virus challenge.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine associated enhanced respiratory disease (VAERD) has been described in pigs vaccinated with whole-inactivated influenza virus (WIV) following infection with heterologous influenza A virus (IAV). WIV vaccination elicits production of non-neutralizing antibody that is cross-reactive to the chal...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. Susceptibility of wood ducks to H5N1 highly pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2002, H5N1 highly pathogenic avian influenza (HPAI) viruses have caused mortality in numerous species of wild birds; this is atypical for avian influenza virus (AIV) infections in wild birds, especially for species in the Order Anseriformes. Although these infections document the susceptibili...

  20. Low pathogenicity avian influenza viruses infect chicken layers by different routes of inoculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to develop better control measures against avian influenza (AI) it’s necessary to understand how the virus transmits in poultry. In a previous study in which the infectivity and transmissibility of the pandemic H1N1influenza virus was examined in different poultry species, we found that no ...

  1. Frequency of genomic reassortment of influenza A virus in North American swine, 1998-2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Revealing the frequency and determinants of reassortment among RNA genome segments is fundamental to understanding basic aspects of the biology and evolution of influenza virus. To provide a quantitative comparison of the frequency of genomic reassortment in influenza viruses circulating in North Am...

  2. Kinetics of Coinfection with Influenza A Virus and Streptococcus pneumoniae

    SciTech Connect

    Smith, Amber M.; Adler, Frederick R.; Ribeiro, Ruy M.; Gutenkunst, Ryan N.; McAuley, Julie L.; McCullers, Jonathan A.; Perelson, Alan S.

    2013-03-21

    Secondary bacterial infections are a leading cause of illness and death during epidemic and pandemic influenza. Experimental studies suggest a lethal synergism between influenza and certain bacteria, particularly Streptococcus pneumoniae, but the precise processes involved are unclear. In this paper, to address the mechanisms and determine the influences of pathogen dose and strain on disease, we infected groups of mice with either the H1N1 subtype influenza A virus A/Puerto Rico/8/34 (PR8) or a version expressing the 1918 PB1-F2 protein (PR8-PB1-F2(1918)), followed seven days later with one of two S. pneumoniae strains, type 2 D39 or type 3 A66.1. We determined that, following bacterial infection, viral titers initially rebound and then decline slowly. Bacterial titers rapidly rise to high levels and remain elevated. We used a kinetic model to explore the coupled interactions and study the dominant controlling mechanisms. We hypothesize that viral titers rebound in the presence of bacteria due to enhanced viral release from infected cells, and that bacterial titers increase due to alveolar macrophage impairment. Dynamics are affected by initial bacterial dose but not by the expression of the influenza 1918 PB1-F2 protein. Finally, our model provides a framework to investigate pathogen interaction during coinfections and to uncover dynamical differences based on inoculum size and strain.

  3. B cell fate decisions following influenza virus infection

    PubMed Central

    Rothaeusler, Kristina; Baumgarth, Nicole

    2010-01-01

    Summary Rapidly induced, specific antibodies generated in extrafollicular foci are important components of early immune protection to influenza virus. The signal(s) that prompt B cells to participate in extrafollicular rather than germinal center responses are incompletely understood. To study the regulation of early B cell differentiation events following influenza infection, we exploited earlier findings of a strong contribution of C12 idiotype-expressing B cells to the primary hemagglutinin (HA)-specific response against influenza A/PR/8/34. Using an idiotype-specific mAb to C12 and labeled-HA, in conjunction with multicolor flow cytometry, we followed the fate of C12Id-expressing influenza HA-specific B cells in wildtype BALB/c mice, requiring neither genetic manipulation nor adoptive cell transfer. Our studies demonstrate that HA-specific C12Id+ B cells are phenotypically indistinguishable from follicular B cells. While they induced both extrafollicular and germinal center responses, extrafollicular responses were strongly predominant. Provision of increased HA-specific T cell help increased the magnitude of the extrafollicular response, but did not shift the C12Id+ response towards germinal center formation. Collectively the data are consistent with the hypothesis that B cell fate-determination following activation is a stochastic process in which infection-induced innate signals might drive the preferential expansion of the early extrafollicular response. PMID:19946883

  4. A fast track influenza virus vaccine produced in insect cells.

    PubMed

    Cox, Manon M J; Hashimoto, Yoshifumi

    2011-07-01

    The viral surface protein hemagglutinin (HA) has been recognized as a key antigen in the host response to influenza virus in both natural infection and vaccination because neutralizing antibodies directed against HA can mitigate or prevent infection. The baculovirus-insect cell system can be used for the production of recombinant HA molecules and is suitable for influenza vaccine production where annual adjustment of the vaccine is required. This expression system is generally considered safe with minimal potential for growth of human pathogens. Extensive characterization of this novel cell substrate has been performed, none of which has revealed the presence of adventitious agents. Multiple clinical studies have demonstrated that the vaccine is safe, well-tolerated and immunogenic. The baculovirus-insect cell system could, therefore, be used for the expedited production of a safe and efficacious influenza vaccine. As a result, this technology should provide a fast track worldwide solution for newly emerging influenza strains or pandemic preparedness within a few years. PMID:21784229

  5. Kinetics of Coinfection with Influenza A Virus and Streptococcus pneumoniae

    DOE PAGESBeta

    Smith, Amber M.; Adler, Frederick R.; Ribeiro, Ruy M.; Gutenkunst, Ryan N.; McAuley, Julie L.; McCullers, Jonathan A.; Perelson, Alan S.

    2013-03-21

    Secondary bacterial infections are a leading cause of illness and death during epidemic and pandemic influenza. Experimental studies suggest a lethal synergism between influenza and certain bacteria, particularly Streptococcus pneumoniae, but the precise processes involved are unclear. In this paper, to address the mechanisms and determine the influences of pathogen dose and strain on disease, we infected groups of mice with either the H1N1 subtype influenza A virus A/Puerto Rico/8/34 (PR8) or a version expressing the 1918 PB1-F2 protein (PR8-PB1-F2(1918)), followed seven days later with one of two S. pneumoniae strains, type 2 D39 or type 3 A66.1. We determinedmore » that, following bacterial infection, viral titers initially rebound and then decline slowly. Bacterial titers rapidly rise to high levels and remain elevated. We used a kinetic model to explore the coupled interactions and study the dominant controlling mechanisms. We hypothesize that viral titers rebound in the presence of bacteria due to enhanced viral release from infected cells, and that bacterial titers increase due to alveolar macrophage impairment. Dynamics are affected by initial bacterial dose but not by the expression of the influenza 1918 PB1-F2 protein. Finally, our model provides a framework to investigate pathogen interaction during coinfections and to uncover dynamical differences based on inoculum size and strain.« less

  6. Previous infection with a mesogenic strain of Newcastle disease virus affects infection with highly pathogenic avian influenza viruses in chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most important viruses affecting poultry worldwide, but little is known on the interactions between these two viruses when infecting birds. In a previous study we found that infection of chickens with a mesogenic strain of...

  7. Experimental co-infection studies with avian influenza viruses and Newcastle Disease viruses in chickens, turkeys and domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Co-infections of poultry with Newcastle Disease viruses (NDVs) and Avian Influenza viruses (AIVs) present a problem both from the clinical point of view and the diagnosis of these viruses. Little has been done to understand the interactions between these two viruses when infecting poultry. Exposur...

  8. Type- and subtype-specific detection of influenza viruses in clinical specimens by rapid culture assay.

    PubMed

    Ziegler, T; Hall, H; Sánchez-Fauquier, A; Gamble, W C; Cox, N J

    1995-02-01

    A rapid culture assay which allows for the simultaneous typing and subtyping of currently circulating influenza A(H1N1), A(H3N2), and B viruses in clinical specimens was developed. Pools of monoclonal antibodies (MAbs) against influenza A and B viruses and MAbs HA1-71 and HA2-76, obtained by immunizing mice with the denatured hemagglutinin subfragments HA1 and HA2 of influenza virus A/Victoria/3/75, were used for immunoperoxidase staining of antigens in infected MDCK cells. MAb HA1-71 reacted exclusively with influenza A viruses of the H3 subtype, while MAb HA2-76 reacted with subtypes H1, H3, H4, H6, H8, H9, H10, H11, and H12, as determined with 78 human, 4 swine, and 10 avian influenza virus reference strains subtyped by the hemagglutination inhibition test. To determine if the technique can be used as a rapid diagnostic test, 263 known influenza virus-positive frozen nasal or throat swabs were inoculated into MDCK cells. After an overnight incubation, the cells were fixed and viral antigens were detected by immunoperoxidase staining. Influenza A viruses of the H1 and H3 subtypes were detected in 31 and 113 specimens, respectively. The subtypes of 10 influenza A virus-positive specimens could not be determined because they contained too little virus. Influenza B viruses were detected in 84 specimens, and 25 specimens were negative. We conclude that this assay is a rapid, convenient, non-labor-intensive, and relatively inexpensive test for detecting, typing, and subtyping influenza viruses in clinical specimens. PMID:7714186

  9. Dynamical correlations in the escape strategy of Influenza A virus

    NASA Astrophysics Data System (ADS)

    Taggi, L.; Colaiori, F.; Loreto, V.; Tria, F.

    2013-03-01

    The evolutionary dynamics of human Influenza A virus presents a challenging theoretical problem. An extremely high mutation rate allows the virus to escape, at each epidemic season, the host immune protection elicited by previous infections. At the same time, at each given epidemic season a single quasi-species, that is a set of closely related strains, is observed. A non-trivial relation between the genetic (i.e., at the sequence level) and the antigenic (i.e., related to the host immune response) distances can shed light into this puzzle. In this paper we introduce a model in which, in accordance with experimental observations, a simple interaction rule based on spatial correlations among point mutations dynamically defines an immunity space in the space of sequences. We investigate the static and dynamic structure of this space and we discuss how it affects the dynamics of the virus-host interaction. Interestingly we observe a staggered time structure in the virus evolution as in the real Influenza evolutionary dynamics.

  10. Lethal dissemination of H5N1 influenza virus is associated with dysregulation of inflammation and lipoxin signaling in a mouse model of infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Periodic outbreaks of highly pathogenic avian H5N1 influenza viruses, and the current H1N1 pandemic, highlight the need for a more detailed understanding of influenza virus pathogenesis. The continued emergence of new influenza viruses highlights the need to better understand influenza virus-host in...

  11. Generation of Influenza Virus from Avian Cells Infected by Salmonella Carrying the Viral Genome

    PubMed Central

    Zhang, Xiangmin; Kong, Wei; Wanda, Soo-Young; Xin, Wei; Alamuri, Praveen; Curtiss, Roy

    2015-01-01

    Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 107 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo. PMID:25742162

  12. Correlation between Virus Replication and Antibody Responses in Macaques following Infection with Pandemic Influenza A Virus

    PubMed Central

    Koopman, Gerrit; Dekking, Liesbeth; Mortier, Daniëlla; Nieuwenhuis, Ivonne G.; van Heteren, Melanie; Kuipers, Harmjan; Remarque, Edmond J.; Radošević, Katarina; Bogers, Willy M. J. M.

    2015-01-01

    ABSTRACT Influenza virus infection of nonhuman primates is a well-established animal model for studying pathogenesis and for evaluating prophylactic and therapeutic intervention strategies. However, usually a standard dose is used for the infection, and there is no information on the relation between challenge dose and virus replication or the induction of immune responses. Such information is also very scarce for humans and largely confined to evaluation of attenuated virus strains. Here, we have compared the effect of a commonly used dose (4 × 106 50% tissue culture infective doses) versus a 100-fold-higher dose, administered by intrabronchial installation, to two groups of 6 cynomolgus macaques. Animals infected with the high virus dose showed more fever and had higher peak levels of gamma interferon in the blood. However, virus replication in the trachea was not significantly different between the groups, although in 2 out of 6 animals from the high-dose group it was present at higher levels and for a longer duration. The virus-specific antibody response was not significantly different between the groups. However, antibody enzyme-linked immunosorbent assay, virus neutralization, and hemagglutination inhibition antibody titers correlated with cumulative virus production in the trachea. In conclusion, using influenza virus infection in cynomolgus macaques as a model, we demonstrated a relationship between the level of virus production upon infection and induction of functional antibody responses against the virus. IMPORTANCE There is only very limited information on the effect of virus inoculation dose on the level of virus production and the induction of adaptive immune responses in humans or nonhuman primates. We found only a marginal and variable effect of virus dose on virus production in the trachea but a significant effect on body temperature. The induction of functional antibody responses, including virus neutralization titer, hemagglutination inhibition

  13. Modified Vaccinia Virus Ankara Encoding Influenza Virus Hemagglutinin Induces Heterosubtypic Immunity in Macaques

    PubMed Central

    Florek, Nicholas W.; Weinfurter, Jason T.; Jegaskanda, Sinthujan; Brewoo, Joseph N.; Powell, Tim D.; Young, Ginger R.; Das, Subash C.; Hatta, Masato; Broman, Karl W.; Hungnes, Olav; Dudman, Susanne G.; Kawaoka, Yoshihiro; Kent, Stephen J.; Stinchcomb, Dan T.

    2014-01-01

    ABSTRACT Current influenza virus vaccines primarily aim to induce neutralizing antibodies (NAbs). Modified vaccinia virus Ankara (MVA) is a safe and well-characterized vector for inducing both antibody and cellular immunity. We evaluated the immunogenicity and protective efficacy of MVA encoding influenza virus hemagglutinin (HA) and/or nucleoprotein (NP) in cynomolgus macaques. Animals were given 2 doses of MVA-based vaccines 4 weeks apart and were challenged with a 2009 pandemic H1N1 isolate (H1N1pdm) 8 weeks after the last vaccination. MVA-based vaccines encoding HA induced potent serum antibody responses against homologous H1 or H5 HAs but did not stimulate strong T cell responses prior to challenge. However, animals that received MVA encoding influenza virus HA and/or NP had high frequencies of virus-specific CD4+ and CD8+ T cell responses within the first 7 days of H1N1pdm infection, while animals vaccinated with MVA encoding irrelevant antigens did not. We detected little or no H1N1pdm replication in animals that received vaccines encoding H1 (homologous) HA, while a vaccine encoding NP from an H5N1 isolate afforded no protection. Surprisingly, H1N1pdm viral shedding was reduced in animals vaccinated with MVA encoding HA and NP from an H5N1 isolate. This reduced shedding was associated with cross-reactive antibodies capable of mediating antibody-dependent cellular cytotoxicity (ADCC) effector functions. Our results suggest that ADCC plays a role in cross-protective immunity against influenza. Vaccines optimized to stimulate cross-reactive antibodies with ADCC function may provide an important measure of protection against emerging influenza viruses when NAbs are ineffective. IMPORTANCE Current influenza vaccines are designed to elicit neutralizing antibodies (NAbs). Vaccine-induced NAbs typically are effective but highly specific for particular virus strains. Consequently, current vaccines are poorly suited for preventing the spread of newly emerging

  14. Comparison of pathogenicities of H7 avian influenza viruses via intranasal and conjunctival inoculation in cynomolgus macaques.

    PubMed

    Shichinohe, Shintaro; Itoh, Yasushi; Nakayama, Misako; Ozaki, Hiroichi; Soda, Kosuke; Ishigaki, Hirohito; Okamatsu, Masatoshi; Sakoda, Yoshihiro; Kida, Hiroshi; Ogasawara, Kazumasa

    2016-06-01

    The outbreak of H7N9 low pathogenic avian influenza viruses in China has attracted attention to H7 influenza virus infection in humans. Since we have shown that the pathogenicity of H1N1 and H5N1 influenza viruses in macaques was almost the same as that in humans, we compared the pathogenicities of H7 avian influenza viruses in cynomolgus macaques via intranasal and conjunctival inoculation, which mimics natural infection in humans. H7N9 virus, as well as H7N7 highly pathogenic avian influenza virus, showed more efficient replication and higher pathogenicity in macaques than did H7N1 and H7N3 highly pathogenic avian influenza viruses. These results are different from pathogenicity in chickens as reported previously. Therefore, our results obtained in macaques help to estimate the pathogenicity of H7 avian influenza viruses in humans. PMID:26994587

  15. Influenza virus infections in the tropics during the first year of life.

    PubMed

    Libraty, Daniel H; Zhang, Lei; Caponpon, Mercydina; Capeding, Rosario Z

    2015-08-01

    Pediatric influenza virus infections in the tropics, particularly during infancy, are not well described. We identified influenza virus infections among infants with non-dengue acute undifferentiated febrile illnesses in San Pablo, Laguna, Philippines, as part of an ongoing clinical study of dengue virus infections during infancy. We found that 31% of infants with non-dengue acute undifferentiated febrile illnesses in San Pablo, Laguna, Philippines, had influenza virus infections. The majority were influenza A virus infections and outpatient cases. The infant ages were 11.1 [9.8-13.0] months (median [95% confidence interval]), and the cases clustered between June and December. Influenza episodes are a common cause of non-dengue acute undifferentiated febrile illnesses in the tropics during the first year of life. PMID:25828834

  16. Influenza A virus (H3N8) in dogs with respiratory disease, Florida.

    PubMed

    Payungporn, Sunchai; Crawford, P Cynda; Kouo, Theodore S; Chen, Li-mei; Pompey, Justine; Castleman, William L; Dubovi, Edward J; Katz, Jacqueline M; Donis, Ruben O

    2008-06-01

    In 2004, canine influenza virus subtype H3N8 emerged in greyhounds in the United States. Subsequent serologic evidence indicated virus circulation in dog breeds other than greyhounds, but the virus had not been isolated from affected animals. In 2005, we conducted virologic investigation of 7 nongreyhound dogs that died from respiratory disease in Florida and isolated influenza subtype H3N8 virus. Antigenic and genetic analysis of A/canine/Jacksonville/2005 (H3N8) and A/canine/Miami/2005 (H3N8) found similarity to earlier isolates from greyhounds, which indicates that canine influenza viruses are not restricted to greyhounds. The hemagglutinin contained 5 conserved amino acid differences that distinguish canine from equine lineages. The antigenic homogeneity of the canine viruses suggests that measurable antigenic drift has not yet occurred. Continued surveillance and antigenic analyses should monitor possible emergence of antigenic variants of canine influenza virus. PMID:18507900

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection.

    PubMed

    Heaton, Nicholas S; Moshkina, Natasha; Fenouil, Romain; Gardner, Thomas J; Aguirre, Sebastian; Shah, Priya S; Zhao, Nan; Manganaro, Lara; Hultquist, Judd F; Noel, Justine; Sachs, David; Sachs, David H; Hamilton, Jennifer; Leon, Paul E; Chawdury, Amit; Tripathi, Shashank; Melegari, Camilla; Campisi, Laura; Hai, Rong; Metreveli, Giorgi; Gamarnik, Andrea V; García-Sastre, Adolfo; Greenbaum, Benjamin; Simon, Viviana; Fernandez-Sesma, Ana; Krogan, Nevan J; Mulder, Lubbertus C F; van Bakel, Harm; Tortorella, Domenico; Taunton, Jack; Palese, Peter; Marazzi, Ivan

    2016-01-19

    Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies. PMID:26789921

  19. Role of receptor binding specificity in influenza A virus transmission and pathogenesis

    PubMed Central

    de Graaf, Miranda; Fouchier, Ron A M

    2014-01-01

    The recent emergence of a novel avian A/H7N9 influenza virus in poultry and humans in China, as well as laboratory studies on adaptation and transmission of avian A/H5N1 influenza viruses, has shed new light on influenza virus adaptation to mammals. One of the biological traits required for animal influenza viruses to cross the species barrier that received considerable attention in animal model studies, in vitro assays, and structural analyses is receptor binding specificity. Sialylated glycans present on the apical surface of host cells can function as receptors for the influenza virus hemagglutinin (HA) protein. Avian and human influenza viruses typically have a different sialic acid (SA)-binding preference and only few amino acid changes in the HA protein can cause a switch from avian to human receptor specificity. Recent experiments using glycan arrays, virus histochemistry, animal models, and structural analyses of HA have added a wealth of knowledge on receptor binding specificity. Here, we review recent data on the interaction between influenza virus HA and SA receptors of the host, and the impact on virus host range, pathogenesis, and transmission. Remaining challenges and future research priorities are also discussed. PMID:24668228

  20. Replication-competent influenza A viruses expressing a red fluorescent protein

    PubMed Central

    Nogales, Aitor; Baker, Steven F.; Martínez-Sobrido, Luis

    2014-01-01

    Like most animal viruses, studying influenza A in model systems requires secondary methodologies to identify infected cells. To circumvent this requirement, we describe the generation of replication-competent influenza A red fluorescent viruses. These influenza A viruses encode mCherry fused to the viral non-structural 1 (NS1) protein and display comparable growth kinetics to wild-type viruses in vitro. Infection of cells with influenza A mCherry viruses was neutralized with monoclonal antibodies and inhibited with antivirals to levels similar to wild-type virus. Influenza A mCherry viruses were also able to lethally infect mice, and strikingly, dose- and time-dependent kinetics of viral replication were monitored in whole excised mouse lungs using an in vivo imaging system (IVIS). By eliminating the need for secondary labeling of infected cells, influenza A mCherry viruses provide an ideal tool in the ongoing struggle to better characterize the virus and identify new therapeutics against influenza A viral infections. PMID:25553516

  1. Avian influenza A viruses in birds of the order Psittaciformes: reports on virus isolations, transmission experiments and vaccinations and initial studies on innocuity and efficacy of oseltamivir in ovo.

    PubMed

    Kaleta, E F; Blanco Peña, K M; Yilmaz, A; Redmann, T; Hofheinz, S

    2007-07-01

    Birds of the order Psittaciformes are - besides chickens, turkeys and other birds - also susceptible to infection with avian influenza A viruses (AIV) and succumb following severe disease within one week. Published data prove that various parakeets, amazons, cockatoos, African grey parrots and budgerigars (genera Barnardius, Psittacula, Cacatua, Eolophus, Amazona, Myiopsitta, Psittacus and Melopsittacus) were found dead following natural infections. Natural infections of highly pathogenic avian influenza viruses (HPAIV) of the haemagglutinin subtypes H5 and H7 cause severe disease and high rates of mortality. Experimental transmission studies with AlVs of the subtypes H5 and H7 confirm these data. Viruses of the subtypes H3N8, H4N6, H4N8, H11N6 and H11N8 may cause also clinical signs and occasionally losses in naturally infected psittacine birds. Clinical signs and losses were also noted following experimental infection of budgerigars with a H4N6 virus. In the EU and in other countries, vaccination of exposed exotic and rare birds and poultry is a possible and an acceptable measure to provide protection. Currently, the EU Commission accepts inactivated adjuvanted vaccines whereas in some other countries recently developed vector vaccines are applied. However, birds remain susceptible during the time interval between application of any vaccine and the development of immunity. This critical period can be bridged with antiviral drugs. Our in ovo studies demonstrate that the neuraminidase inhibitor oseltamivir is non-toxic for chicken embryos at concentrations of 0.1, 1.0 and 10.0 mg/kg body weight. These dosages prevented entirely the replication of a HPAIV of the subtype H7N1 when this drug is given shortly prior to, simultaneously or soon after inoculation of chicken embryos with this AIV. Thus, we speculate that exposed valuable birds such as psittacines at risk can be successfully treated. PMID:17724934

  2. Replication-Competent Influenza A Viruses Expressing Reporter Genes

    PubMed Central

    Breen, Michael; Nogales, Aitor; Baker, Steven F.; Martínez-Sobrido, Luis

    2016-01-01

    Influenza A viruses (IAV) cause annual seasonal human respiratory disease epidemics. In addition, IAV have been implicated in occasional pandemics with inordinate health and economic consequences. Studying IAV, in vitro or in vivo, requires the use of laborious secondary methodologies to identify virus-infected cells. To circumvent this requirement, replication-competent IAV expressing an easily traceable reporter protein can be used. Here we discuss the development and applications of recombinant replication-competent IAV harboring diverse fluorescent or bioluminescent reporter genes in different locations of the viral genome. These viruses have been employed for in vitro and in vivo studies, such as the screening of neutralizing antibodies or antiviral compounds, the identification of host factors involved in viral replication, cell tropism, the development of vaccines, or the assessment of viral infection dynamics. In summary, reporter-expressing, replicating-competent IAV represent a powerful tool for the study of IAV both in vitro and in vivo. PMID:27347991

  3. Replication-Competent Influenza A Viruses Expressing Reporter Genes.

    PubMed

    Breen, Michael; Nogales, Aitor; Baker, Steven F; Martínez-Sobrido, Luis

    2016-01-01

    Influenza A viruses (IAV) cause annual seasonal human respiratory disease epidemics. In addition, IAV have been implicated in occasional pandemics with inordinate health and economic consequences. Studying IAV, in vitro or in vivo, requires the use of laborious secondary methodologies to identify virus-infected cells. To circumvent this requirement, replication-competent IAV expressing an easily traceable reporter protein can be used. Here we discuss the development and applications of recombinant replication-competent IAV harboring diverse fluorescent or bioluminescent reporter genes in different locations of the viral genome. These viruses have been employed for in vitro and in vivo studies, such as the screening of neutralizing antibodies or antiviral compounds, the identification of host factors involved in viral replication, cell tropism, the development of vaccines, or the assessment of viral infection dynamics. In summary, reporter-expressing, replicating-competent IAV represent a powerful tool for the study of IAV both in vitro and in vivo. PMID:27347991

  4. Innate immunity to influenza virus: implications for future therapy

    PubMed Central

    White, Mitchell R; Doss, Mona; Boland, Patrick; Tecle, Tesfaldet; Hartshorn, Kevan L

    2009-01-01

    Innate immunity is critical in the early containment of influenza virus infection. The innate response is surprisingly complex. A variety of soluble innate inhibitors in respiratory secretions provide an initial barrier to infection. Dendritic cells, phagocytes and natural killer cells mediate viral clearance and promote further innate and adaptive responses. Toll-like receptors 3 and 7 and cytoplasmic RNA sensors are critical for activating these responses. In general, the innate response restricts viral replication without injuring the lung; however, the 1918 pandemic and H5N1 strains cause more profound, possibly harmful, innate responses. In this review, we discuss the implications of burgeoning knowledge of innate immunity for therapy of influenza. PMID:19756245

  5. Compounds with anti-influenza activity: present and future of strategies for the optimal treatment and management of influenza. Part II: Future compounds against influenza virus.

    PubMed

    Gasparini, R; Amicizia, D; Lai, P L; Bragazzi, N L; Panatto, D

    2014-12-01

    In the first part of this overview, we described the life cycle of the influenza virus and the pharmacological action of the currently available drugs. This second part provides an overview of the molecular mechanisms and targets of still-experimental drugs for the treatment and management of influenza. Briefly, we can distinguish between compounds with anti-influenza activity that target influenza virus proteins or genes, and molecules that target host components that are essential for viral replication and propagation. These latter compounds have been developed quite recently. Among the first group, we will focus especially on hemagglutinin, M2 channel and neuraminidase inhibitors. The second group of compounds may pave the way for personalized treatment and influenza management. Combination therapies are also discussed. In recent decades, few antiviral molecules against influenza virus infections have been available; this has conditioned their use during human and animal outbreaks. Indeed, during seasonal and pandemic outbreaks, antiviral drugs have usually been administered in mono-therapy and, sometimes, in an uncontrolled manner to farm animals. This has led to the emergence of viral strains displaying resistance, especially to compounds of the amantadane family. For this reason, it is particularly important to develop new antiviral drugs against influenza viruses. Indeed, although vaccination is the most powerful means of mitigating the effects of influenza epidemics, antiviral drugs can be very useful, particularly in delaying the spread of new pandemic viruses, thereby enabling manufacturers to prepare large quantities of pandemic vaccine. In addition, antiviral drugs are particularly valuable in complicated cases of influenza, especially in hospitalized patients. To write this overview, we mined various databases, including Embase, PubChem, DrugBank and Chemical Abstracts Service, and patent repositories. PMID:26137785

  6. Influenza A Virus Polymerase Is a Site for Adaptive Changes during Experimental Evolution in Bat Cells

    PubMed Central

    Poole, Daniel S.; Yú, Shuǐqìng; Caì, Yíngyún; Dinis, Jorge M.; Müller, Marcel A.; Jordan, Ingo; Friedrich, Thomas C.; Kuhn, Jens H.

    2014-01-01

    ABSTRACT The recent identification of highly divergent influenza A viruses in bats revealed a new, geographically dispersed viral reservoir. To investigate the molecular mechanisms of host-restricted viral tropism and the potential for transmission of viruses between humans and bats, we exposed a panel of cell lines from bats of diverse species to a prototypical human-origin influenza A virus. All of the tested bat cell lines were susceptible to influenza A virus infection. Experimental evolution of human and avian-like viruses in bat cells resulted in efficient replication and created highly cytopathic variants. Deep sequencing of adapted human influenza A virus revealed a mutation in the PA polymerase subunit not previously described, M285K. Recombinant virus with the PA M285K mutation completely phenocopied the adapted virus. Adaptation of an avian virus-like virus resulted in the canonical PB2 E627K mutation that is required for efficient replication in other mammals. None of the adaptive mutations occurred in the gene for viral hemagglutinin, a gene that frequently acquires changes to recognize host-specific variations in sialic acid receptors. We showed that human influenza A virus uses canonical sialic acid receptors to infect bat cells, even though bat influenza A viruses do not appear to use these receptors for virus entry. Our results demonstrate that bats are unique hosts that select for both a novel mutation and a well-known adaptive mutation in the viral polymerase to support replication. IMPORTANCE Bats constitute well-known reservoirs for viruses that may be transferred into human populations, sometimes with fatal consequences. Influenza A viruses have recently been identified in bats, dramatically expanding the known host range of this virus. Here we investigated the replication of human influenza A virus in bat cell lines and the barriers that the virus faces in this new host. Human influenza A and B viruses infected cells from geographically and

  7. Influenza: the virus and prophylaxis with inactivated influenza vaccine in “at risk” groups, including COPD patients

    PubMed Central

    Hovden, Arnt-Ove; Cox, Rebecca Jane; Haaheim, Lars Reinhardt

    2007-01-01

    Influenza is a major respiratory pathogen, which exerts a huge human and economic toll on society. Influenza is a vaccine preventable disease, however, the vaccine strains must be annually updated due to the continuous antigenic changes in the virus. Inactivated influenza vaccines have been used for over 50 years and have an excellent safety record. Annual vaccination is therefore recommended for all individuals with serious medical conditions, like COPD, and protects the vaccinee against influenza illness and also against hospitalization and death. In COPD patients, influenza infection can lead to exacerbations resulting in reduced quality of life, hospitalization and death in the most severe cases. Although there is only limited literature on the use of influenza vaccination solely in COPD patients, there is clearly enough evidence to recommend annual vaccination in this group. This review will focus on influenza virus and prophylaxis with inactivated influenza vaccines in COPD patients and other “at risk” groups to reduce morbidity, save lives, and reduce health care costs. PMID:18229561

  8. 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

  9. Functional Genomics Reveals Linkers Critical for Influenza Virus Polymerase

    PubMed Central

    Wang, Lulan; Wu, Aiping; Wang, Yao E.; Quanquin, Natalie; Li, Chunfeng; Wang, Jingfeng; Chen, Hsiang-Wen; Liu, Suyang; Liu, Ping; Zhang, Hong; Qin, F. Xiao-Feng

    2015-01-01

    ABSTRACT Influenza virus mRNA synthesis by the RNA-dependent RNA polymerase involves binding and cleavage of capped cellular mRNA by the PB2 and PA subunits, respectively, and extension of viral mRNA by PB1. However, the mechanism for such a dynamic process is unclear. Using high-throughput mutagenesis and sequencing analysis, we have not only generated a comprehensive functional map for the microdomains of individual subunits but also have revealed the PA linker to be critical for polymerase activity. This PA linker binds to PB1 and also forms ionic interactions with the PA C-terminal channel. Nearly all mutants with five-amino-acid insertions in the linker were nonviable. Our model further suggests that the PA linker plays an important role in the conformational changes that occur between stages that favor capped mRNA binding and cleavage and those associated with viral mRNA synthesis. IMPORTANCE The RNA-dependent RNA polymerase of influenza virus consists of the PB1, PB2, and PA subunits. By combining genome-wide mutagenesis analysis with the recently discovered crystal structure of the influenza polymerase heterotrimer, we generated a comprehensive functional map of the entire influenza polymerase complex. We identified the microdomains of individual subunits, including the catalytic domains, the interaction interfaces between subunits, and nine linkers interconnecting different domains. Interestingly, we found that mutants with five-amino-acid insertions in individual linkers were nonviable, suggesting the critical roles these linkers play in coordinating spatial relationships between the subunits. We further identified an extended PA linker that binds to PB1 and also forms ionic interactions with the PA C-terminal channel. PMID:26719244

  10. Bioaerosol sampling for the detection of aerosolized influenza virus

    PubMed Central

    Blachere, Francoise M.; Lindsley, William G.; Slaven, James E.; Green, Brett J.; Anderson, Stacey E.; Chen, Bean T.; Beezhold, Don H.

    2007-01-01

    Background Influenza virus was used to characterize the efficacy of a cyclone‐based, two‐stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles. Methods A Collison single‐jet nebulizer was used to aerosolize the attenuated FluMist® vaccine into a calm‐air settling chamber. Viral particles were captured with bioaerosol samplers that utilize 2 microcentrifuge tubes to collect airborne particulates. The first tube (T1) collects particles greater than 1.8 μm in diameter, while the second tube (T2) collects particles between 1.0 and 1.8 μm, and the back‐up filter (F) collects submicron particles. Following aerosolization, quantitative PCR was used to detect and quantify H1N1 and H3N2 influenza strains. Results Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two‐stage bioaerosol sampler. Most viral particles were collected in T2 (1‐1.8 μm) and on the back‐up filter (< 1 μm) of the bioaerosol sampler. Furthermore, we found that the detection of viral particles with the two‐stage sampler was directly proportional to the collection time. Consequently, viral particle counts were significantly greater at 40 minutes in comparison to 5, 10 and 20 minute aerosol collection points. Conclusions Due to a lack of empirical data, aerosol transmission of influenza is often questioned. Using FluMist®, we demonstrated that a newly developed bioaerosol sampler is able to recover and size fractionate aerosolized viral particles. This sampler should be an important tool for studying viral transmission in clinical settings and may significantly contribute towards understanding the modes of influenza virus transmission. PMID:19453416

  11. Infection of dogs with equine influenza virus: evidence for transmission from horses during the Australian outbreak.

    PubMed

    Crispe, E; Finlaison, D S; Hurt, A C; Kirkland, P D

    2011-07-01

    During the equine influenza (EI) outbreak, respiratory disease was observed in dogs that were in close proximity to infected horses. Investigations were undertaken to exclude influenza virus infection. Of the 23 dogs that were seropositive in tests using the influenza A/Sydney/2007 virus as the test antigen, 10 showed clinical signs. EI virus appeared to be readily transmitted to dogs that were held in close proximity to infected horses, but there was no evidence of lateral transmission of the virus to other dogs that did not have contact with or were not held in close proximity to horses. PMID:21711279

  12. The role of avian/human-like influenza polymerase genes in the adaptation of influenza viruses to pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Around 1998, reassortment events occurred in pigs in the U.S. which resulted in the transfer of avian and human influenza genes into "classical" H1N1 (cH1N1) swine influenza viruses (SIV) producing novel H3N2, H1N2, H3N1 and reassortant H1N1 (rH1N1) viruses. These novel H3N2, H1N2 and rH1N1 viruses ...

  13. Influenza A Virus Attenuation by Codon Deoptimization of the NS Gene for Vaccine Development

    PubMed Central

    Nogales, Aitor; Baker, Steven F.; Ortiz-Riaño, Emilio; Dewhurst, Stephen; Topham, David J.

    2014-01-01

    ABSTRACT Influenza viral infection represents a serious public health problem that causes contagious respiratory disease, which is most effectively prevented through vaccination to reduce transmission and future infection. The nonstructural (NS) gene of influenza A virus encodes an mRNA transcript that is alternatively spliced to express two viral proteins, the nonstructural protein 1 (NS1) and the nuclear export protein (NEP). The importance of the NS gene of influenza A virus for viral replication and virulence has been well described and represents an attractive target to generate live attenuated influenza viruses with vaccine potential. Considering that most amino acids can be synthesized from several synonymous codons, this study employed the use of misrepresented mammalian codons (codon deoptimization) for the de novo synthesis of a viral NS RNA segment based on influenza A/Puerto Rico/8/1934 (H1N1) (PR8) virus. We generated three different recombinant influenza PR8 viruses containing codon-deoptimized synonymous mutations in coding regions comprising the entire NS gene or the mRNA corresponding to the individual viral protein NS1 or NEP, without modifying the respective splicing and packaging signals of the viral segment. The fitness of these synthetic viruses was attenuated in vivo, while they retained immunogenicity, conferring both homologous and heterologous protection against influenza A virus challenges. These results indicate that influenza viruses can be effectively attenuated by synonymous codon deoptimization of the NS gene and open the possibility of their use as a safe vaccine to prevent infections with these important human pathogens. IMPORTANCE Vaccination serves as the best therapeutic option to protect humans against influenza viral infections. However, the efficacy of current influenza vaccines is suboptimal, and novel approaches are necessary for the prevention of disease cause by this important human respiratory pathogen. The nonstructural

  14. Experimental co-infection of chickens and turkeys with avian influenza and newcastle disease viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) and Newcastle disease virus (NDV) are the two most important viruses affecting poultry worldwide. Co-infections of poultry with AIV and NDV are a problem from both the clinical point of view and the diagnosis of these viruses. The goal of this study was to examine the i...

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

    PubMed Central

    Peiris, JS Malik; Poon, Leo LM; Guan, Yi

    2016-01-01

    A recently emerged novel influenza A H1N1 virus continues to spread globally. The virus contains a novel constellation of gene segments, the nearest known precursors being viruses found in swine and it likely arose through reassortment of two or more viruses of swine origin. H1N1, H1N2 and H3N2 subtype swine influenza viruses have occasionally infected humans before but such zoonotic transmission-events did not lead to sustained human-to-human transmission in the manner this swine-origin influenza virus (S-OIV) has done. Its transmission among humans appears to be higher than that observed with seasonal influenza. Children and young adults appear to those most affected and also those who appear to maintain transmission. Clinical disease generally appears mild but complications leading to hospitalization can occur, especially in those with underlying lung or cardiac disease, diabetes or those on immunosuppresive therapies. There are concerns that the virus may reassort with existing human influenza virus giving rise to more transmissible or more pathogenic viruses. The virus appears to retain the potential to transmit back to swine and thus continued reassortment with swine viruses is a cause for concern. PMID:19540800

  16. Transmission of Avian Influenza Virus (H3N2) to Dogs

    PubMed Central

    Song, Daesub; Kang, Bokyu; Lee, Chulseung; Jung, Kwonil; Ha, Gunwoo; Kang, Dongseok; Park, Seongjun; Park, Bongkyun

    2008-01-01

    In South Korea, where avian influenza virus subtypes H3N2, H5N1, H6N1, and H9N2 circulate or have been detected, 3 genetically similar canine influenza virus (H3N2) strains of avian origin (A/canine/Korea/01/2007, A/canine/Korea/02/2007, and A/canine/Korea/03/2007) were isolated from dogs exhibiting severe respiratory disease. To determine whether the novel canine influenza virus of avian origin was transmitted among dogs, we experimentally infected beagles with this influenza virus (H3N2) isolate. The beagles shed virus through nasal excretion, seroconverted, and became ill with severe necrotizing tracheobronchitis and bronchioalveolitis with accompanying clinical signs (e.g., high fever). Consistent with histologic observation of lung lesions, large amounts of avian influenza virus binding receptor (SAα 2,3-gal) were identified in canine tracheal, bronchial, and bronchiolar epithelial cells, which suggests potential for direct transmission of avian influenza virus (H3N2) from poultry to dogs. Our data provide evidence that dogs may play a role in interspecies transmission and spread of influenza virus. PMID:18439355

  17. Susceptibility of influenza viruses circulating in Western Saudi Arabia to neuraminidase inhibitors

    PubMed Central

    Tolah, Ahmed M.; Azhar, Esam I.; Hashem, Anwar M.

    2016-01-01

    Objectives: To investigate the sensitivity of circulating influenza viruses in Western Saudi Arabia to neuraminidase inhibitors (NAIs); mainly, zanamivir and oseltamivir. Methods: Respiratory samples were collected from patients presenting with respiratory symptoms to King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia (KSA) between September 2013 and October 2014. All samples were tested prospectively by real-time reverse-transcription polymerase chain reaction for influenza A and B viruses. Positive samples were then inoculated on Madin-Darby Canine Kidney (MDCK) cells and isolated viruses were examined for their sensitivity to NAIs using fluorescent neuraminidase inhibition assay. Results: Out of 406 tested samples, 25 samples (6.2%) were positive for influenza A/pdmH1N1 virus, one sample (0.25%) was positive for influenza A/H3N2 virus, and 7 samples (1.7%) were positive for influenza B Yamagata-like virus. Screening of isolated influenza A and B viruses (9 out of 33) for their sensitivity to NAIs showed no significant resistance to available NAIs. Conclusion: Our results show that circulating influenza viruses in Jeddah are still sensitive to NAIs. PMID:27052292

  18. Continuous Influenza Virus Production in Cell Culture Shows a Periodic Accumulation of Defective Interfering Particles

    PubMed Central

    Pflugmacher, Antje; Behrendt, Ilona; Jordan, Ingo; Flockerzi, Dietrich; Genzel, Yvonne; Reichl, Udo

    2013-01-01

    Influenza viruses are a major public health burden during seasonal epidemics and a continuous threat due to their potential to cause pandemics. Annual vaccination provides the best protection against the contagious respiratory illness caused by influenza viruses. However, the current production capacities for influenza vaccines are insufficient to meet the increasing demands. We explored the possibility to establish a continuous production process for influenza viruses using the duck-derived suspension cell line AGE1.CR. A two-stage bioreactor setup was designed in which cells were cultivated in a first stirred tank reactor where an almost constant cell concentration was maintained. Cells were then constantly fed to a second bioreactor where virus infection and replication took place. Using this two-stage reactor system, it was possible to continuously produce influenza viruses. Surprisingly, virus titers showed a periodic increase and decrease during the run-time of 17 days. These titer fluctuations were caused by the presence of defective interfering particles (DIPs), which we detected by PCR. Mathematical modeling confirmed this observation showing that constant virus titers can only emerge in the absence of DIPs. Even with very low amounts of DIPs in the seed virus and very low rates for de novo DIP generation, defective viruses rapidly accumulate and, therefore, represent a serious challenge for continuous vaccine production. Yet, the continuous replication of influenza virus using a two-stage bioreactor setup is a novel tool to study aspects of viral evolution and the impact of DIPs. PMID:24039749

  19. Protective immunity and safety of a genetically modified influenza virus vaccine.

    PubMed

    Barbosa, Rafael Polidoro Alves; Salgado, Ana Paula Carneiro; Garcia, Cristiana Couto; Filho, Bruno Galvão; Gonçalves, Ana Paula de Faria; Lima, Braulio Henrique Freire; Lopes, Gabriel Augusto Oliveira; Rachid, Milene Alvarenga; Peixoto, Andiara Cristina Cardoso; de Oliveira, Danilo Bretas; Ataíde, Marco Antônio; Zirke, Carla Aparecida; Cotrim, Tatiane Marques; Costa, Érica Azevedo; Almeida, Gabriel Magno de Freitas; Russo, Remo Castro; Gazzinelli, Ricardo Tostes; Machado, Alexandre de Magalhães Vieira

    2014-01-01

    Recombinant influenza viruses are promising viral platforms to be used as antigen delivery vectors. To this aim, one of the most promising approaches consists of generating recombinant viruses harboring partially truncated neuraminidase (NA) segments. To date, all studies have pointed to safety and usefulness of this viral platform. However, some aspects of the inflammatory and immune responses triggered by those recombinant viruses and their safety to immunocompromised hosts remained to be elucidated. In the present study, we generated a recombinant influenza virus harboring a truncated NA segment (vNA-Δ) and evaluated the innate and inflammatory responses and the safety of this recombinant virus in wild type or knock-out (KO) mice with impaired innate (Myd88 -/-) or acquired (RAG -/-) immune responses. Infection using truncated neuraminidase influenza virus was harmless regarding lung and systemic inflammatory response in wild type mice and was highly attenuated in KO mice. We also demonstrated that vNA-Δ infection does not induce unbalanced cytokine production that strongly contributes to lung damage in infected mice. In addition, the recombinant influenza virus was able to trigger both local and systemic virus-specific humoral and CD8+ T cellular immune responses which protected immunized mice against the challenge with a lethal dose of homologous A/PR8/34 influenza virus. Taken together, our findings suggest and reinforce the safety of using NA deleted influenza viruses as antigen delivery vectors against human or veterinary pathogens. PMID:24927156

  20. Complete nucleotide sequence of the nucleoprotein gene of influenza B virus.

    PubMed Central

    Londo, D R; Davis, A R; Nayak, D P

    1983-01-01

    A DNA copy of influenza B/Singapore/222/79 viral RNA segment 5, containing the gene coding for the nucleoprotein (NP), has been cloned in Escherichia coli plasmid pBR322, and its nucleotide sequence has been determined. The influenza B NP gene contains 1,839 nucleotides and codes for a protein of 560 amino acids with a molecular weight of 61,593. Comparison of the influenza B NP amino acid sequence with that of influenza A NP (A/PR/8/34) reveals 37% direct homology in the aligned regions, indicating a common ancestor. However, influenza B NP has an additional 50 amino acids at its N-terminal end. As is the case with influenza A NP, influenza B NP is a basic protein, with its charged residues relatively evenly distributed rather than clustered. The structural homology suggests functional similarity between the NP of influenza A and B viruses. PMID:6688639

  1. A predictive fitness model for influenza

    NASA Astrophysics Data System (ADS)

    Łuksza, Marta; Lässig, Michael

    2014-03-01

    The seasonal human influenza A/H3N2 virus undergoes rapid evolution, which produces significant year-to-year sequence turnover in the population of circulating strains. Adaptive mutations respond to human immune challenge and occur primarily in antigenic epitopes, the antibody-binding domains of the viral surface protein haemagglutinin. Here we develop a fitness model for haemagglutinin that predicts the evolution of the viral population from one year to the next. Two factors are shown to determine the fitness of a strain: adaptive epitope changes and deleterious mutations outside the epitopes. We infer both fitness components for the strains circulating in a given year, using population-genetic data of all previous strains. From fitness and frequency of each strain, we predict the frequency of its descendent strains in the following year. This fitness model maps the adaptive history of influenza A and suggests a principled method for vaccine selection. Our results call for a more comprehensive epidemiology of influenza and other fast-evolving pathogens that integrates antigenic phenotypes with other viral functions coupled by genetic linkage.

  2. Highly Pathogenic Avian Influenza Virus Subtype H5N1 Escaping Neutralization: More than HA Variation

    PubMed Central

    Höper, Dirk; Kalthoff, Donata; Hoffmann, Bernd

    2012-01-01

    Influenza A viruses are one of the major threats in modern health care. Novel viruses arise due to antigenic drift and antigenic shift, leading to escape from the immune system and resulting in a serious problem for disease control. In order to investigate the escape process and to enable predictions of escape, we serially passaged influenza A H5N1 virus in vitro 100 times under immune pressure. The generated escape viruses were characterized phenotypically and in detail by full-genome deep sequencing. Mutations already found in natural isolates were detected, evidencing the in vivo relevance of the in vitro-induced amino acid substitutions. Additionally, several novel alterations were triggered. Altogether, the results imply that our in vitro system is suitable to study influenza A virus evolution and that it might even be possible to predict antigenic changes of influenza A viruses circulating in vaccinated populations. PMID:22090121

  3. Effects of Aging on Influenza Virus Infection Dynamics

    PubMed Central

    Hernandez-Vargas, Esteban A.; Wilk, Esther; Canini, Laetitia; Toapanta, Franklin R.; Binder, Sebastian C.; Uvarovskii, Alexey; Ross, Ted M.; Guzmán, Carlos A.

    2014-01-01

    ABSTRACT The consequences of influenza virus infection are generally more severe in individuals over 65 years of age (the elderly). Immunosenescence enhances the susceptibility to viral infections and renders vaccination less effective. Understanding age-related changes in the immune system is crucial in order to design prophylactic and immunomodulatory strategies to reduce morbidity and mortality in the elderly. Here, we propose different mathematical models to provide a quantitative understanding of the immune strategies in the course of influenza virus infection using experimental data from young and aged mice. Simulation results suggested a central role of CD8+ T cells for adequate viral clearance kinetics in young and aged mice. Adding the removal of infected cells by natural killer cells did not improve the model fit in either young or aged animals. We separately examined the infection-resistant state of cells promoted by the cytokines alpha/beta interferon (IFN-α/β), IFN-γ, and tumor necrosis factor alpha (TNF-α). The combination of activated CD8+ T cells with any of the cytokines provided the best fits in young and aged animals. During the first 3 days after infection, the basic reproductive number for aged mice was 1.5-fold lower than that for young mice (P < 0.05). IMPORTANCE The fits of our models to the experimental data suggest that the increased levels of IFN-α/β, IFN-γ, and TNF-α (the “inflammaging” state) promote slower viral growth in aged mice, which consequently limits the stimulation of immune cells and contributes to the reported impaired responses in the elderly. A quantitative understanding of influenza virus pathogenesis and its shift in the elderly is the key contribution of this work. PMID:24478442

  4. Evaluation of the Cepheid Xpert Flu Assay for rapid identification and differentiation of influenza A, influenza A 2009 H1N1, and influenza B viruses.

    PubMed

    Novak-Weekley, S M; Marlowe, E M; Poulter, M; Dwyer, D; Speers, D; Rawlinson, W; Baleriola, C; Robinson, C C

    2012-05-01

    The Xpert Flu Assay cartridge is a next-generation nucleic acid amplification system that provides multiplexed PCR detection of the influenza A, influenza A 2009 H1N1, and influenza B viruses in approximately 70 min with minimal hands-on time. Six laboratories participated in a clinical trial comparing the results of the new Cepheid Xpert Flu Assay to those of culture or real-time PCR with archived and prospectively collected nasal aspirate-wash (NA-W) specimens and nasopharyngeal (NP) swabs from children and adults. Discrepant results were resolved by DNA sequence analysis. After discrepant-result analysis, the sensitivities of the Xpert Flu Assay for prospective NA-W specimens containing the influenza A, influenza A 2009 H1N1, and influenza B viruses compared to those of culture were 90.0%, 100%, and 100%, respectively, while the sensitivities of the assay for prospective NP swabs compared to those of culture were 100%, 100%, and 100%, respectively. The sensitivities of the Xpert Flu Assay for archived NA-W specimens compared to those of Gen-Probe ProFlu+ PCR for the influenza A, influenza A 2009 H1N1, and influenza B viruses were 99.4%, 98.4%, and 100%, respectively, while the sensitivities of the Xpert Flu Assay for archived NP swabs compared to those of ProFlu+ were 98.1%, 100%, and 93.8%, respectively. The sensitivities of the Xpert Flu Assay with archived NP specimens compared to those of culture for the three targets were 97.5%, 100%, and 93.8%, respectively. We conclude that the Cepheid Xpert Flu Assay is an accurate and rapid method that is suitable for on-demand testing for influenza viral infection. PMID:22378908

  5. Evaluation of the Cepheid Xpert Flu Assay for Rapid Identification and Differentiation of Influenza A, Influenza A 2009 H1N1, and Influenza B Viruses

    PubMed Central

    Marlowe, E. M.; Poulter, M.; Dwyer, D.; Speers, D.; Rawlinson, W.; Baleriola, C.; Robinson, C. C.

    2012-01-01

    The Xpert Flu Assay cartridge is a next-generation nucleic acid amplification system that provides multiplexed PCR detection of the influenza A, influenza A 2009 H1N1, and influenza B viruses in approximately 70 min with minimal hands-on time. Six laboratories participated in a clinical trial comparing the results of the new Cepheid Xpert Flu Assay to those of culture or real-time PCR with archived and prospectively collected nasal aspirate-wash (NA-W) specimens and nasopharyngeal (NP) swabs from children and adults. Discrepant results were resolved by DNA sequence analysis. After discrepant-result analysis, the sensitivities of the Xpert Flu Assay for prospective NA-W specimens containing the influenza A, influenza A 2009 H1N1, and influenza B viruses compared to those of culture were 90.0%, 100%, and 100%, respectively, while the sensitivities of the assay for prospective NP swabs compared to those of culture were 100%, 100%, and 100%, respectively. The sensitivities of the Xpert Flu Assay for archived NA-W specimens compared to those of Gen-Probe ProFlu+ PCR for the influenza A, influenza A 2009 H1N1, and influenza B viruses were 99.4%, 98.4%, and 100%, respectively, while the sensitivities of the Xpert Flu Assay for archived NP swabs compared to those of ProFlu+ were 98.1%, 100%, and 93.8%, respectively. The sensitivities of the Xpert Flu Assay with archived NP specimens compared to those of culture for the three targets were 97.5%, 100%, and 93.8%, respectively. We conclude that the Cepheid Xpert Flu Assay is an accurate and rapid method that is suitable for on-demand testing for influenza viral infection. PMID:22378908

  6. LINGUISTIC ANALYSIS OF THE NUCLEOPROTEIN GENE OF INFLUENZA A VIRUS

    SciTech Connect

    A. SKOURIKHINE; T. BURR

    2000-05-01

    We applied linguistic analysis approach, specifically N-grams, to classify nucleotide and amino acids sequences of nucleoprotein (NP) gene of the Influenza A virus isolated from a range of hosts and geographic regions. We considered letter frequency (1-grams), letter pairs frequency (2-grams) and triplets' frequency (3-grams). Classification trees based on 1,2,3-grams variables were constructed for the same NP nucleotide and amino acids strains and their classification efficiency were compared with the clustering obtained using phylogenetic analysis. The results have shown that disregarding positional information for a NP gene can provide the same level of recognition accuracy like alternative more complex classification techniques.

  7. Detection method for avian influenza viruses in water.

    PubMed

    Rönnqvist, Maria; Ziegler, Thedi; von Bonsdorff, Carl-Henrik; Maunula, Leena

    2012-03-01

    Recent events have shown that humans may become infected with some pathogenic avian influenza A viruses (AIV). Since soil and water, including lakes, rivers, and seashores, may be contaminated by AIV excreted by birds, effective methods are needed for monitoring water for emerging viruses. Combining water filtration with molecular methods such as PCR is a fast and effective way for detecting viruses. The objective of this study was to apply a convenient method for the detection of AIV in natural water samples. Distilled water and lake, river, and seawater were artificially contaminated with AIV (H5N3) and passed through a filter system. AIV was detected from filter membrane by real-time RT-PCR. The performance of Zetapor, SMWP, and Sartobind D5F membranes in recovering influenza viruses was first evaluated using contaminated distilled water. SWMP, which gave the highest virus recoveries, was then compared with a pre-filter combined GF/F filter membrane in a trial using natural water samples. In this study, the cellulose membrane SMWP was found to be practical for recovery of AIVs in water. Viral yields varied between 62.1 and 65.9% in distilled water and between 1 and 16.7% in natural water samples. The borosilicate glass membrane GF/F combined with pre-filter was also feasible in filtering natural water samples with viral yields from 1.98 to 7.33%. The methods described can be used for monitoring fresh and seawater samples for the presence of AIV and to determine the source of AIV transmission in an outbreak situation. PMID:23412765

  8. The Functional Study of the N-Terminal Region of Influenza B Virus Nucleoprotein

    PubMed Central

    Liu, Ming; Lam, Mandy Ka-Han; Zhang, Qinfen; Elderfield, Ruth; Barclay, Wendy S.; Shaw, Pang-Chui

    2015-01-01

    Influenza nucleoprotein (NP) is a major component of the ribonucleoprotein (vRNP) in influenza virus, which functions for the transcription and replication of viral genome. Compared to the nucleoprotein of influenza A (ANP), the N-terminal region of influenza B nucleoprotein (BNP) is much extended. By virus reconstitution, we found that the first 38 residues are essential for viral growth. We further illustrated the function of BNP by mini-genome reconstitution, fluorescence microscopy, electron microscopy, light scattering and gel shift. Results show that the N terminus is involved in the formation of both higher homo-oligomers of BNP and BNP-RNA complex. PMID:26368391

  9. Protection against multiple subtypes of influenza viruses by virus-like particle vaccines based on a hemagglutinin conserved epitope.

    PubMed

    Chen, Shaoheng; Zheng, Dan; Li, Changgui; Zhang, Wenjie; Xu, Wenting; Liu, Xueying; Fang, Fang; Chen, Ze

    2015-01-01

    We selected the conserved sequence in the stalk region of influenza virus hemagglutinin (HA) trimmer, the long alpha helix (LAH), as the vaccine candidate sequence, and inserted it into the major immunodominant region (MIR) of hepatitis B virus core protein (HBc), and, by using the E. coli expression system, we prepared a recombinant protein vaccine LAH-HBc in the form of virus-like particles (VLP). Intranasal immunization of mice with this LAH-HBc VLP plus cholera toxin B subunit with 0.2% of cholera toxin (CTB(*)) adjuvant could effectively elicit humoral and cellular immune responses and protect mice against a lethal challenge of homologous influenza viruses (A/Puerto Rico/8/1934 (PR8) (H1N1)). In addition, passage of the immune sera containing specific antibodies to naïve mice rendered them resistant against a lethal homologous challenge. Immunization with LAH-HBc VLP vaccine plus CTB(*) adjuvant could also fully protect mice against a lethal challenge of the 2009 pandemic H1N1 influenza virus or the avian H9N2 virus and could partially protect mice against a lethal challenge of the avian H5N1 influenza virus. This study demonstrated that the LAH-HBc VLP vaccine based on a conserved sequence of the HA trimmer stalk region is a promising candidate vaccine for developing a universal influenza vaccine against multiple influenza viruses infections. PMID:25767809

  10. Hemagglutinin of influenza A virus binds specifically to cell surface nucleolin and plays a role in virus internalization.

    PubMed

    Chan, Che-Man; Chu, Hin; Zhang, Anna Jinxia; Leung, Lai-Han; Sze, Kong-Hung; Kao, Richard Yi-Tsun; Chik, Kenn Ka-Heng; To, Kelvin Kai-Wang; Chan, Jasper Fuk-Woo; Chen, Honglin; Jin, Dong-Yan; Liu, Liang; Yuen, Kwok-Yung

    2016-07-01

    The hemagglutinin (HA) protein of influenza A virus initiates cell entry by binding to sialic acids on target cells. In the current study, we demonstrated that in addition to sialic acids, influenza A/Puerto Rico/8/34 H1N1 (PR8) virus HA specifically binds to cell surface nucleolin (NCL). The interaction between HA and NCL was initially revealed with virus overlay protein binding assay (VOPBA) and subsequently verified with co-immunoprecipitation. Importantly, inhibiting cell surface NCL with NCL antibody, blocking PR8 viruses with purified NCL protein, or depleting endogenous NCL with siRNA all substantially reduced influenza virus internalization. We further demonstrated that NCL was a conserved cellular factor required for the entry of multiple influenza A viruses, including H1N1, H3N2, H5N1, and H7N9. Overall, our findings identified a novel role of NCL in influenza virus life cycle and established NCL as one of the host cell surface proteins for the entry of influenza A virus. PMID:27085069

  11. Proton Channel Activity of Influenza A Virus Matrix Protein 2 Contributes to Autophagy Arrest

    PubMed Central

    Ren, Yizhong; Feng, Liqiang; Pan, Weiqi; Li, Liang; Wang, Qian; Li, Jiashun; Li, Na; Han, Ling; Zheng, Xuehua; Niu, Xuefeng; Sun, Caijun

    2015-01-01

    Influenza A virus infection can arrest autophagy, as evidenced by autophagosome accumulation in infected cells. Here, we report that this autophagosome accumulation can be inhibited by amantadine, an antiviral proton channel inhibitor, in amantadine-sensitive virus infected cells or cells expressing influenza A virus matrix protein 2 (M2). Thus, M2 proton channel activity plays a role in blocking the fusion of autophagosomes with lysosomes, which might be a key mechanism for arresting autophagy. PMID:26468520

  12. Induction of a Protective Heterosubtypic Immune Response Against the Influenza Virus by using Recombinant Adenoviral Vectors Expressing Hemagglutinin of the Influenza H5 Virus.

    PubMed

    Shmarov, M M; Sedova, E S; Verkhovskaya, L V; Rudneva, I A; Bogacheva, E A; Barykova, Yu A; Shcherbinin, D N; Lysenko, A A; Tutykhina, I L; Logunov, D Y; Smirnov, Yu A; Naroditsky, B S; Gintsburg, A L

    2010-04-01

    Influenza viruses are characterized by a high degree of antigenic variability, which causes the annual emergence of flu epidemics and irregularly timed pandemics caused by viruses with new antigenic and biological traits. Novel approaches to vaccination can help circumvent this problem. One of these new methods incorporates genetic vaccines based on adenoviral vectors. Recombinant adenoviral vectors which contain hemagglutinin-encoding genes from avian H5N1 and H5N2 (Ad-HA5-1 and Ad-HA5-2) influenza viruses were obtained using the AdEasy Adenoviral Vector System (Stratagene). Laboratory mice received a double intranasal vaccination with Ad-HA5-1 and Ad-HA5-2. This study demonstrates that immunization with recombinant adenoviruses bearing the Н 5 influenza virus hemagglutinin gene induces a immune response which protects immunized mice from a lethal dose of the H5 influenza virus. Moreover, it also protects the host from a lethal dose of the H1 virus, which belongs to the same clade as H5, but does not confer protection from the subtype H3 influenza virus, which belongs to a different clade. PMID:22649637

  13. Surveillance and identification of influenza A viruses in wild aquatic birds in the Crimea, Ukraine (2006-2008)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ecology of avian influenza (AI) viruses in wild aquatic birds of Asia is poorly understood. From March 2006 through November 2008, 20 avian influenza viruses were isolated in the Crimea region of Ukraine, with an overall virus isolation frequency of 3.3%. All the viruses were isolated from thr...

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

    PubMed Central

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

    2011-01-01

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

  15. Antigenic and genetic analysis of a recently isolated H1N1 swine influenza virus.

    PubMed

    Olsen, C W; McGregor, M W; Cooley, A J; Schantz, B; Hotze, B; Hinshaw, V S

    1993-10-01

    Hemagglutinins (HA) of H1N1 swine influenza viruses isolated in the United States have remained antigenically and genetically conserved for many years. In contrast to such conservation, the HA of A/Swine/Nebraska/1/92 (Sw/Neb) could readily be distinguished from those of contemporary porcine viruses. Twenty-eight amino acid mutations differentiated the HA of Sw/Neb and A/Swine/Indiana/1726/88, the most recent H1N1 swine influenza virus for which HA sequence data were available. Among these differences were mutations at potential asparagine-linked glycosylation sites and charge changes at many residues. The Sw/Neb virus also could be differentiated from other swine influenza viruses in hemagglutination-inhibition assays with monoclonal antibodies to recent H1 swine HA. Nonetheless, overall sequence analysis of the HA and the nucleoprotein genes of Sw/Neb indicated that this virus was more closely related genetically to classic H1N1 swine influenza viruses than to H1N1 avian or human viruses. Infection of swine with Sw/Neb under experimental conditions induced clinical signs and lesions typical of swine influenza. However, affected swine in the field had high, persistent fevers, but relatively mild signs of respiratory tract disease. This study indicated that an antigenically and genetically novel variant of swine influenza virus was detected in the United States. PMID:8250388

  16. A Review of the Antiviral Susceptibility of Human and Avian Influenza Viruses over the Last Decade

    PubMed Central

    Oh, Ding Yuan; Hurt, Aeron C.

    2014-01-01

    Antivirals play an important role in the prevention and treatment of influenza infections, particularly in high-risk or severely ill patients. Two classes of influenza antivirals have been available in many countries over the last decade (2004–2013), the adamantanes and the neuraminidase inhibitors (NAIs). During this period, widespread adamantane resistance has developed in circulating influenza viruses rendering these drugs useless, resulting in the reliance on the most widely available NAI, oseltamivir. However, the emergence of oseltamivir-resistant seasonal A(H1N1) viruses in 2008 demonstrated that NAI-resistant viruses could also emerge and spread globally in a similar manner to that seen for adamantane-resistant viruses. Previously, it was believed that NAI-resistant viruses had compromised replication and/or transmission. Fortunately, in 2013, the majority of circulating human influenza viruses remain sensitive to all of the NAIs, but significant work by our laboratory and others is now underway to understand what enables NAI-resistant viruses to retain the capacity to replicate and transmit. In this review, we describe how the susceptibility of circulating human and avian influenza viruses has changed over the last ten years and describe some research studies that aim to understand how NAI-resistant human and avian influenza viruses may emerge in the future. PMID:24800107

  17. Development and evaluation of a polydiacetylene based biosensor for the detection of H5 influenza virus.

    PubMed

    Jiang, Lixiang; Luo, Jing; Dong, Wenjie; Wang, Chengmin; Jin, Wen; Xia, Yuetong; Wang, Haijing; Ding, Hua; Jiang, Long; He, Hongxuan

    2015-07-01

    H5N1 avian influenza has caused serious economic losses as well as posed significant threats to public health, agriculture and wildlife. It is important to develop a rapid, sensitive and specific detection platform suitable for disease surveillance and control. In this study, a highly sensitive, specific and rapid biosensor based on polydiacetylene was developed for detecting H5 influenza virus. The polydiacetylene based biosensor was produced from an optimized ratio of 10,12-pentacosadiynoic acid and 1,2-dimyristoyl-sn-glycero-3-phosphocholine, with the anti-H5 influenza antibody embedded onto the vesicle surface. The optimized polydiacetylene vesicle could detect H5 influenza virus sensitively with a detection limit of 0.53 copies/μL, showing a dramatic blue-to-red color change that can be observed directly by the naked eye and recorded by a UV-vis spectrometer. The sensitivity, specificity and accuracy of the biosensor were also evaluated. The sensor could specifically differentiate H5 influenza virus from H3 influenza virus, Newcastle disease virus and porcine reproductive and respiratory syndrome virus. Detection using tracheal swabs was in accord with virus isolation results, and comparable to the RT-PCR method. These results offer the possibility and potential of simple polydiacetylene based bio-analytical method for influenza surveillance. PMID:25819686

  18. Ultrasensitive detection of influenza viruses with a glycan-based impedimetric biosensor.

    PubMed

    Hushegyi, András; Pihíková, Dominika; Bertok, Tomas; Adam, Vojtech; Kizek, René; Tkac, Jan

    2016-05-15

    An ultrasensitive impedimetric glycan-based biosensor for reliable and selective detection of inactivated, but intact influenza viruses H3N2 was developed. Such glycan-based approach has a distinct advantage over antibody-based detection of influenza viruses since glycans are natural viral receptors with a possibility to selectively distinguish between potentially pathogenic influenza subtypes by the glycan-based biosensors. Build-up of the biosensor was carefully optimized with atomic force microscopy applied for visualization of the biosensor surface after binding of viruses with the topology of an individual viral particle H3N2 analyzed. The glycan biosensor could detect a glycan binding lectin with a limit of detection (LOD) of 5 aM. The biosensor was finally applied for analysis of influenza viruses H3N2 with LOD of 13 viral particles in 1 μl, what is the lowest LOD for analysis of influenza viral particles by the glycan-based device achieved so far. The biosensor could detect H3N2 viruses selectively with a sensitivity ratio of 30 over influenza viruses H7N7. The impedimetric biosensor presented here is the most sensitive glycan-based device for detection of influenza viruses and among the most sensitive antibody or aptamer based biosensor devices. PMID:26765527

  19. Uncovering the Potential Pan Proteomes Encoded by Genomic Strand RNAs of Influenza A Viruses

    PubMed Central

    Yang, Chu-Wen; Chen, Mei-Fang

    2016-01-01

    Influenza A virus genomes are composed of eight negative sense RNAs. In total, 16 proteins encoded by eight positive sense RNAs were identified. One putative protein coding sequence (PCS) encoded by genomic strand RNA of segment 8 has been previously proposed. In this study, 95,608, 123,965 and 35,699 genomic strand RNA sequences from influenza A viruses from avian, human and mammalian hosts, respectively, were used to identify PCSs encoded by the genomic strand RNAs. In total, 326,069 PCSs with lengths equal to or longer than 80 amino acids were identified and clustered into 270 PCS groups. Twenty of the 270 PCS groups which have greater than 10% proportion in influenza A viruses from avian, human or mammalian hosts were selected for detailed study. Maps of the 20 PCSGs in the influenza A virus genomes were constructed. The proportions of the 20 PCSGs in influenza A viruses from different hosts and serotypes were analyzed. One secretory and five membrane proteins predicted from the PCS groups encoded by genomic strand RNAs of segments 1, 2, 4, 6, 7 and 8 were identified. These results suggest the possibility of the ambisense nature of the influenza A virus genomic RNAs and a potential coding sequence reservoir encoding potential pan proteomes of influenza A viruses. PMID:26761196

  20. Quantitative Subcellular Proteome and Secretome Profiling of Influenza A Virus-Infected Human Primary Macrophages

    PubMed Central

    Lietzén, Niina; Julkunen, Ilkka; Aittokallio, Tero; Matikainen, Sampsa; Nyman, Tuula A.

    2011-01-01

    Influenza A viruses are important pathogens that cause acute respiratory diseases and annual epidemics in humans. Macrophages recognize influenza A virus infection with their pattern recognition receptors, and are involved in the activation of proper innate immune response. Here, we have used high-throughput subcellular proteomics combined with bioinformatics to provide a global view of host cellular events that are activated in response to influenza A virus infection in human primary macrophages. We show that viral infection regulates the expression and/or subcellular localization of more than one thousand host proteins at early phases of infection. Our data reveals that there are dramatic changes in mitochondrial and nuclear proteomes in response to infection. We show that a rapid cytoplasmic leakage of lysosomal proteins, including cathepsins, followed by their secretion, contributes to inflammasome activation and apoptosis seen in the infected macrophages. Also, our results demonstrate that P2X7 receptor and src tyrosine kinase activity are essential for inflammasome activation during influenza A virus infection. Finally, we show that influenza A virus infection is associated with robust secretion of different danger-associated molecular patterns (DAMPs) suggesting an important role for DAMPs in host response to influenza A virus infection. In conclusion, our high-throughput quantitative proteomics study provides important new insight into host-response against influenza A virus infection in human primary macrophages. PMID:21589892