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Sample records for influenza virus haemagglutinin

  1. Studies on polysomes synthesizing influenza virus haemagglutinin.

    PubMed

    Melnikov SYa; Mikheeva, A V; Ghendon, Y Z

    1982-01-01

    A fraction of polysomes synthesizing fowl plague virus (FPV) haemagglutinin (HA) was isolated from an infected chick embryo fibroblast (CEF) culture using a double immunoprecipitation assay. In an immunoprecipitate of HA-synthesizing polysomes (HA precipitate) the content of the HA polypeptide was increased with respect to the M1 + NS1 polypeptides as compared to a preparation of unprecipitated polysomes. In the HA precipitate, besides mRNA coding for HA synthesis, we have detected mRNAs corresponding to genes 1, 2 and 3 coding for high molecular weight P proteins. Studies of a cytoplasmic extract (CE) from FPV-infected CEF cultures in a sucrose density gradient revealed a fraction of polysomes with a sedimentation value of about 500S; the composition of virus-specific polypeptides and mRNA of the fraction was similar to that of the HA precipitate. It is thought that P proteins are synthesized on membrane-bound polysomes located closely to HA-synthesizing polysomes.

  2. The international reference preparation of influenza virus haemagglutinin (type A).

    PubMed

    Krag, P; Bentzon, M W

    1971-01-01

    This paper describes the international collaborative assay that led to the establishment in 1967 of the International Reference Preparation of Influenza Virus Haemagglutinin (Type A) and the studies completed during the following years on the use of the preparation for evaluating the haemagglutinin content of 46 influenza virus vaccines in terms of international units. The WHO Expert Committee on Biological Standardization (1967) defined the International Unit as 0,09361 mg of the International Reference Preparation.Altogether 14 laboratories in 12 countries took part in one or both studies, using a total of 24 methods (HA titrations and, in a few cases CCA titrations). Major differences in the HA titres were found between laboratories, while the potencies (the haemagglutinin content values) relative to the International Reference Preparation were free from most of these differences. Haemagglutination titres varied over a range factor up to 50, while the corresponding relative "potencies" varied with a factor of only 2. The CCA method used in a few laboratories gave results close to the lowest haemagglutination titres and showed relatively small variations between laboratories. The analyses of variance disclosed differences in the variation within laboratories, but for the majority of the laboratories the variation allowed an overall estimate of a standard error.The calculation of haemagglutinin content (in IU) from relative potencies is described. Advice is given on the selection, preparation, and titration of a local reference vaccine with a view to expressing its haemagglutinin content in international units.The test results with 46 local vaccines are also given. The deviations of the relative potencies from the average per vaccine showed a distribution with eight major discrepancies instead of the expected one. The background for these cases is discussed.

  3. 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

  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. Interaction of influenza virus haemagglutinin with sphingolipid-cholesterol membrane domains via its transmembrane domain.

    PubMed Central

    Scheiffele, P; Roth, M G; Simons, K

    1997-01-01

    Sphingolipid-cholesterol rafts are microdomains in biological membranes with liquid-ordered phase properties which are implicated in membrane traffic and signalling events. We have used influenza virus haemagglutinin (HA) as a model protein to analyse the interaction of transmembrane proteins with these microdomains. Here we demonstrate that raft association is an intrinsic property encoded in the protein. Mutant HA molecules with foreign transmembrane domain (TMD) sequences lose their ability to associate with the lipid microdomains, and mutations in the HA TMD reveal a requirement for hydrophobic residues in contact with the exoplasmic leaflet of the membrane. We also provide experimental evidence that cholesterol is critically required for association of proteins with lipid rafts. Our data suggest that the binding to specific membrane domains can be encoded in transmembrane proteins and that this information will be used for polarized sorting and signal transduction processes. PMID:9312009

  6. 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

  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. Characterization of an enhanced antigenic change in the pandemic 2009 H1N1 influenza virus haemagglutinin.

    PubMed

    García-Barreno, Blanca; Delgado, Teresa; Benito, Sonia; Casas, Inmaculada; Pozo, Francisco; Cuevas, María Teresa; Mas, Vicente; Trento, Alfonsina; Rodriguez-Frandsen, Ariel; Falcón, Ana; Ortín, Juan; Nieto, Amelia; Melero, José A

    2014-05-01

    Murine hybridomas producing neutralizing mAbs specific to the pandemic influenza virus A/California/07/2009 haemagglutinin (HA) were isolated. These antibodies recognized at least two different but overlapping new epitopes that were conserved in the HA of most Spanish pandemic isolates. However, one of these isolates (A/Extremadura/RR6530/2010) lacked reactivity with the mAbs and carried two unique mutations in the HA head (S88Y and K136N) that were required simultaneously to eliminate reactivity with the murine antibodies. This unusual requirement directly illustrates the phenomenon of enhanced antigenic change proposed previously for the accumulation of simultaneous amino acid substitutions at antigenic sites of the influenza A virus HA during virus evolution (Shih et al., Proc Natl Acad Sci USA, 104 , 6283-6288, 2007). The changes found in the A/Extremadura/RR6530/2010 HA were not found in escape mutants selected in vitro with one of the mAbs, which contained instead nearby single amino acid changes in the HA head. Thus, either single or double point mutations may similarly alter epitopes of the new antigenic site identified in this work in the 2009 H1N1 pandemic virus HA. Moreover, this site is relevant for the human antibody response, as shown by competition of mAbs and human post-infection sera for virus binding. The results are discussed in the context of the HA antigenic structure and challenges posed for identification of sequence changes with possible antigenic impact during virus surveillance.

  9. B.K. virus haemagglutinin.

    PubMed

    Kende, M; Uj, M; Szücs, G

    1979-01-01

    Among the widely applied buffered media, the HSAG (hepes-salt-albumin-gelatin) medium at pH 5.75--6.25 was found to be the most favourable for B.K. virus haemagglutinin titration. The optimum temperature was at 4 degrees C. The haemagglutinin was not affected by temperatures up to 37 degrees C, pHs between 5.5 and 9.5, and NaCl concentrations between 0.063 M and 2.56 M. When incubated at 56 degrees C, the haemagglutinin shows a time and pH dependent decline in titre. No significant time dependent titre fall occurred at 56 degrees C if NaCl molarity was varied between 1.31 and 2.56.

  10. 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

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

    PubMed

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

    2014-04-01

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

  12. Sequence analysis of the 2009 pandemic influenza A H1N1 virus haemagglutinin gene from 2009-2010 Brazilian clinical samples.

    PubMed

    Ferreira, João Leandro de Paula; Borborema, Samanta Etel Treiger; Brígido, Luis Fernando de Macedo; Oliveira, Maria Isabel de; Paiva, Terezinha Maria de; Santos, Cecília Luiza Simões dos

    2011-08-01

    In this paper, we analysed the haemagglutinin (HA) gene identified by polymerase chain reaction from 90 influenza A H1N1 virus strains that circulated in Brazil from April 2009-June 2010. A World Health Organization sequencing protocol allowed us to identify amino acid mutations in the HA protein at positions S220T (71%), D239G/N/S (20%), Y247H (4.5%), E252K (3.3%), M274V (2.2%), Q310H (26.7%) and E391K (12%). A fatal outcome was associated with the D239G mutation (p < 0.0001). Brazilian HA genetic diversity, in comparison to a reference strain from California, highlights the role of influenza virus surveillance for study of viral evolution, in addition to monitoring the spread of the virus worldwide.

  13. 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.

  14. Effect of test system on the ability of monoclonal antibodies to detect antigenic drift in influenza A(H1N1) virus haemagglutinins.

    PubMed

    Kendal, A P; Phillips, D J; Webster, R G; Galland, G G; Reimer, C B

    1981-06-01

    Results of analysing antigenic variation in the haemagglutinin (HA) molecule of naturally occurring influenza A (H1N1) viruses from 1977 to 1979 with monoclonal antibodies were found to be dependent in some instances on the test system used. In several instances A/USSR/90/77 HA-specific monoclonal antibodies had sharply reduced haemagglutination-inhibition (HI) titres with variant virus although they bound to the variant and A/USSR/90/77 HAs with similar efficiencies as judged by titration in a sensitive and accurate solid-phase immunofluorimetric assay. In another instance, the converse situation was observed: monoclonal antibodies having a reduced efficiency of binding to the HA of a variant virus nevertheless had comparable HI titres with the variant and with A/USSR/90/77. The chemical basis and epidemiological significance of these observations remain to be elucidated. Nevertheless, the finding that the reaction of monoclonal antibodies can, in some cases, be markedly dependent on the test system employed is of significance for the efficient design and correct interpretation of immunochemical studies which employ monoclonal antibodies to investigate the basis for variation in influenza strains.

  15. Experimental adaptation of an influenza H5 haemagglutinin (HA) confers respiratory droplet transmission to a reassortant H5 HA/H1N1 virus in ferrets

    PubMed Central

    Imai, Masaki; Watanabe, Tokiko; Hatta, Masato; Das, Subash C.; Ozawa, Makoto; Shinya, Kyoko; Zhong, Gongxun; Hanson, Anthony; Katsura, Hiroaki; Watanabe, Shinji; Li, Chengjun; Kawakami, Eiryo; Yamada, Shinya; Kiso, Maki; Suzuki, Yasuo; Maher, Eileen A.; Neumann, Gabriele

    2012-01-01

    Highly pathogenic avian H5N1 influenza A viruses occasionally infect humans, but currently do not transmit efficiently among humans. The viral haemagglutinin (HA) protein is a known host range determinant since it mediates virus binding to host-specific cellular receptors1–3. Here, we therefore assessed the molecular changes in HA that would allow an H5 HA-possessing virus to transmit among mammals. We identified a reassortant virus with H5 HA possessing four mutations in a 2009 pandemic H1N1 virus backbone capable of droplet transmission in a ferret model. The transmissible H5 reassortant virus preferentially recognized human-type receptors, replicated efficiently in ferrets, caused lung lesions and weight loss, but it was not highly pathogenic and did not cause mortality. These results suggest that H5 HA can convert to an HA that supports efficient viral transmission in mammals. However, we do not know whether the four mutations in the H5 HA identified in this study would render a wholly avian H5N1 virus transmissible. The genetic origin of the remaining seven viral genes may also critically contribute to transmissibility in mammals. Nevertheless, as H5N1 viruses continue to evolve and infect humans, receptor-binding variants of H5N1 viruses with pandemic potential, including avian-human reassortant viruses as tested here, may emerge. Our findings emphasize the need for pandemic preparedness for H5 HA-possessing viruses and will help individuals conducting surveillance in regions with circulating H5N1 viruses to recognize key residues that predict the pandemic potential of isolates, which will inform the development, production, and distribution of effective countermeasures. PMID:22722205

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

    PubMed Central

    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

    SUMMARY Influenza A virus hemagglutinin (HA) changes conformation and drives membrane fusion of viral and endosomal membrane at low pH. Membrane fusion proceeds through an intermediate called hemifusion1,2. For viral fusion the hemifusion structures are not determined3. Here, influenza virus-like particles (VLP)4 carrying wild-type (WT) HA or HA hemifusion mutant G1S5 and liposome mixtures were studied at low pH by Volta phase plate (VPP) cryo-electron tomography (cET) which improves signal-to-noise ratio close to focus. We determined two distinct hemifusion structures: a hemifusion diaphragm (HD) and a novel structure termed lipidic junction. Liposomes with lipidic junctions were ruptured with membrane edges stabilized by HA. The rupture frequency and HD diameter were not affected by G1S mutation, but decreased when the cholesterol level in the liposomes was close to physiological concentrations. We propose that HA induces merger between the viral and a target membrane by one of two independent pathways: rupture-insertion pathway leading to lipidic junction and hemifusion-stalk pathway leading to fusion pore. The latter is relevant under the conditions of influenza virus infection of cells. Cholesterol concentration functions as a pathway switch due to its negative spontaneous curvature in the target bilayer as determined by continuum analysis. PMID:27231578

  17. 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

  18. Altered influenza virus haemagglutinin (HA)-derived peptide is potent therapy for CIA by inducing Th1 to Th2 shift.

    PubMed

    Sun, Jian; Jia, Yuan; Li, Ru; Guo, Jianping; Sun, Xiaolin; Liu, Yanying; Li, Yingni; Yao, Haihong; Liu, Xia; Zhao, Jing; Li, Zhanguo

    2011-07-01

    There has been an increase in interest in the use of altered peptides as antigen-specific therapeutic agents in autoimmune diseases. Here we investigated the inhibitory effect and possible mechanism of an altered influenza virus haemagglutinin (HA)-derived peptide in collagen-induced arthritis (CIA). CIA was induced in DBA/1 mice by immunisation with type II collagen (CII). Altered HA308-317, wild-type HA308-317 or irrelevant peptide was administered intranasally beginning from arthritis onset. Clinical and histological scores were assessed, and cytokine levels in the serum or supernatants from splenocytes were determined. The percentages of Th1 and Th2 cells in response to different peptides were analysed by FACS both in vivo and in vitro. Our results showed that intranasal administration of altered HA308-317 peptide significantly ameliorated CIA. The therapeutic effect of altered HA308-317 peptide was associated with a substantial decrease in production of interferon (IFN)-γ, interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, anti-CII IgG, IgG1 and IgG2a antibodies, and an markedly increase in production of IL-10 and IL-4 in serum or supernatants from splenocytes treated with altered HA308-317 peptide. The percentage of Th2 (CD4(+)IL-4(+)) cells was upregulated significantly by altered HA308-317 peptide with a decreased percentage of Th1 (T helper 1; CD4(+)INF-γ(+)) cells both in vivo and in vitro. These findings suggest that altered HA308-317 peptide might be a promising candidate for rheumatoid arthritis (RA) treatment.

  19. Mutation tryptophan to leucine at position 222 of haemagglutinin could facilitate H3N2 influenza A virus infection in dogs

    PubMed Central

    Yang, Guohua; Li, Shoujun; Blackmon, Sherry; Ye, Jianqiang; Bradley, Konrad C.; Cooley, Jim; Smith, Dave; Hanson, Larry; Cardona, Carol; Steinhauer, David A.; Webby, Richard; Liao, Ming

    2013-01-01

    An avian-like H3N2 influenza A virus (IAV) has recently caused sporadic canine influenza outbreaks in China and Korea, but the molecular mechanisms involved in the interspecies transmission of H3N2 IAV from avian to canine species are not well understood. Sequence analysis showed that residue 222 in haemagglutinin (HA) is predominantly tryptophan (W) in the closely related avian H3N2 IAV, but was leucine (L) in canine H3N2 IAV. In this study, reassortant viruses rH3N2-222L (canine-like) and rH3N2-222W (avian-like) with HA mutation L222W were generated using reverse genetics to evaluate the significance of the L222W mutation on receptor binding and host tropism of H3N2 IAV. Compared with rH3N2-222W, rH3N2-222L grew more rapidly in MDCK cells and had significantly higher infectivity in primary canine tracheal epithelial cells. Tissue-binding assays demonstrated that rH3N2-222L had a preference for canine tracheal tissues rather avian tracheal tissues, whereas rH3N2-222W favoured slightly avian rather canine tracheal tissues. Glycan microarray analysis suggested both rH3N2-222L and rH3N2-222W bound preferentially to α2,3-linked sialic acids. However, the rH3N2-222W had more than twofold less binding affinity than rH3N2-222L to a set of glycans with Neu5Aca2–3Galb1–4(Fuca-)-like or Neu5Aca2–3Galb1–3(Fuca-)-like structures. These data suggest the W to L mutation at position 222 of the HA could facilitate infection of H3N2 IAV in dogs, possibly by increasing the binding affinities of the HA to specific receptors with Neu5Aca2–3Galb1–4(Fuca-) or Neu5Aca2–3Galb1–3(Fuca-)-like structures that are present in dogs. PMID:23994833

  20. Transient domains induced by influenza haemagglutinin during membrane fusion.

    PubMed

    Blumenthal, R; Pak, C C; Raviv, Y; Krumbiegel, M; Bergelson, L D; Morris, S J; Lowy, R J

    1995-01-01

    During low pH-induced fusion of influenza virus with erythrocytes we have observed differential dispersion of viral lipid and haemagglutinin (HA) into the erythrocyte membrane, and viral RNA into the erythrocyte using fluorescence video microscopy. The movement of both viral lipid and HA from virus to cell was restricted during the initial stages of fusion relative to free diffusion. This indicates the existence of relatively long-lived barriers to diffusion subsequent to fusion pore formation. Fluorescence anisotropy of phospholipid analogues incorporated into the viral membrane decreased when the pH was lowered to levels required for optimum fusion. This indicates that the restricted motion of viral membrane components was not due to rigidification of membrane lipids. The movement of HA from the fusion site was also assessed by photosensitized labelling by means of a fluorescent substrate (NBD-taurine) passing through the band 3 sialoglycoprotein (the erythrocyte anion transporter). We also examined the flow of lipid and aqueous markers during fusion of HA-expressing cells with labelled erythrocytes. During this cell-cell fusion, movement of lipid between fusing membranes begins before the fusion pore is wide enough to allow diffusion of aqueous molecules (M(r) > 500). The data indicate that HA is capable of creating domains in the membrane and controlling continuity of aqueous compartments which are bounded by such domains.

  1. 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

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

    PubMed

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

    2014-06-01

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

  3. Genetic diversity of the haemagglutinin (HA) of human influenza a (H1N1) virus in montenegro: Focus on its origin and evolution.

    PubMed

    Mugosa, Boban; Vujosevic, Danijela; Ciccozzi, Massimo; Valli, Maria Beatrice; Capobianchi, Maria Rosaria; Lo Presti, Alessandra; Cella, Eleonora; Giovanetti, Marta; Lai, Alessia; Angeletti, Silvia; Scarpa, Fabio; Terzić, Dragica; Vratnica, Zoran

    2016-11-01

    In 2009 an influenza A epidemic caused by a swine origin H1N1strain, unusual in human hosts, has been described. The present research is aimed to perform the first phylogenetic investigation on the influenza virus A (H1N1) strains circulating in Montenegro, from December 1, 2009, when the first case of death due to H1N1 was confirmed, and the epidemic began causing a total of four fatalities. The phylogenetic analysis of the strains circulating showed the absence of a pure Montenegrin cluster, suggesting the occurrence of multiple re-introductions in that population from different areas till as far as the early 2010. The time to most recent common ancestor (TMRCA) for the complete dataset has been dated in early 2008, pre-dating the first Montenegrin identification of H1N1 infection. These data suggest that virus was spreading undetected, may be as a consequence of unidentified infections in returning travelers. Anyhow, the estimated TMRCA of Montenegrin strains is fully consistent to that found in different areas. Compatibly with the time coverage of the study period here analyzed, molecular dynamic of Montenegrin strains follows similar trend as in other countries. J. Med. Virol. 88:1905-1913, 2016. © 2016 Wiley Periodicals, Inc. PMID:27088433

  4. Genetic diversity of the haemagglutinin (HA) of human influenza a (H1N1) virus in montenegro: Focus on its origin and evolution.

    PubMed

    Mugosa, Boban; Vujosevic, Danijela; Ciccozzi, Massimo; Valli, Maria Beatrice; Capobianchi, Maria Rosaria; Lo Presti, Alessandra; Cella, Eleonora; Giovanetti, Marta; Lai, Alessia; Angeletti, Silvia; Scarpa, Fabio; Terzić, Dragica; Vratnica, Zoran

    2016-11-01

    In 2009 an influenza A epidemic caused by a swine origin H1N1strain, unusual in human hosts, has been described. The present research is aimed to perform the first phylogenetic investigation on the influenza virus A (H1N1) strains circulating in Montenegro, from December 1, 2009, when the first case of death due to H1N1 was confirmed, and the epidemic began causing a total of four fatalities. The phylogenetic analysis of the strains circulating showed the absence of a pure Montenegrin cluster, suggesting the occurrence of multiple re-introductions in that population from different areas till as far as the early 2010. The time to most recent common ancestor (TMRCA) for the complete dataset has been dated in early 2008, pre-dating the first Montenegrin identification of H1N1 infection. These data suggest that virus was spreading undetected, may be as a consequence of unidentified infections in returning travelers. Anyhow, the estimated TMRCA of Montenegrin strains is fully consistent to that found in different areas. Compatibly with the time coverage of the study period here analyzed, molecular dynamic of Montenegrin strains follows similar trend as in other countries. J. Med. Virol. 88:1905-1913, 2016. © 2016 Wiley Periodicals, Inc.

  5. Immunoelectron microscopic studies on haemagglutinin and haemolysin of measles virus in infected HEp2 cells.

    PubMed

    Armstrong, M A; Fraser, K B; Dermott, E; Shirodaria, P V

    1982-03-01

    The antigenic determinants of the haemagglutinin and haemolysin antigens of measles virus were located at the surface of HEp2 cells infected with measles virus and on measles virions released from these cells, using immunoelectron microscopy. Antisera specific for haemagglutinin or haemolysin antigen and peroxidase-conjugated antiglobulin were used. Treatment of the infected cells with trypsin removed the virus spikes and prevented binding by the anti-haemagglutinin serum, while the reaction with anti-haemolysin serum was unaltered. This suggests that the antigenic determinants for measles haemagglutinin reside on the spike, while the antigenic determinants for haemolysin reside on, or are close to, the virus membrane. PMID:6175729

  6. 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

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

    PubMed Central

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

    2015-01-01

    Summary 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. © 2015 The Authors. Reviews in Medical Virology published by John Wiley & Sons Ltd. PMID:26467906

  8. 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

  9. 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.

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

    PubMed Central

    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

  11. 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

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

    PubMed

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

    2011-04-27

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

  13. [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.

  14. 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

  15. 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...

  16. 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

  17. ELPylated haemagglutinins produced in tobacco plants induce potentially neutralizing antibodies against H5N1 viruses in mice.

    PubMed

    Phan, Hoang T; Pohl, Julia; Floss, Doreen M; Rabenstein, Frank; Veits, Jutta; Le, Binh T; Chu, Ha H; Hause, Gerd; Mettenleiter, Thomas; Conrad, Udo

    2013-06-01

    Reducing the cost of vaccine production is a key priority for veterinary research, and the possibility of heterologously expressing antigen in plants provides a particularly attractive means of achieving this. Here, we report the expression of the avian influenza virus haemagglutinin (AIV HA) in tobacco, both as a monomer and as a trimer in its native and its ELPylated form. We firstly presented evidence to produce stabilized trimers of soluble HA in plants. ELPylation of these trimers does not influence the trimerization. Strong expression enhancement in planta caused by ELPylation was demonstrated for trimerized H5-ELP. ELPylated trimers could be purified by a membrane-based inverse transition cycling procedure with the potential of successful scale-up. The trimeric form of AIV HA was found to enhance the HA-specific immune response compared with the monomeric form. Plant-derived AIV HA trimers elicited potentially neutralizing antibodies interacting with both homologous virus-like particles from plants and heterologous inactivated AIV. ELPylation did not influence the functionality and the antigenicity of the stabilized H5 trimers. These data allow further developments including scale-up of production, purification and virus challenge experiments with the final goal to achieve suitable technologies for efficient avian flu vaccine production.

  18. Studies on type C influenza virus in the chick embryo.

    PubMed

    Jennings, R; Freeman, M J

    1972-03-01

    The effect of varying conditions of inoculation and incubation on the growth of type C influenza virus in the allantoic cavity of the developing chick embryo were investigated. It was found that the highest yields of both virus haemagglutinin and infectious virus were obtained following the inoculation of chick embryos at 8 days with subsequent incubation at 32 degrees C. Using the chick embryo allantoic cavity for titration of infectious virus, growth curves of allantoically propagated virus under varying inoculation and incubation conditions were determined.

  19. 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

  20. Influenza A virus reassortment.

    PubMed

    Steel, John; Lowen, Anice C

    2014-01-01

    Reassortment is the process by which influenza viruses swap gene segments. This genetic exchange is possible due to the segmented nature of the viral genome and occurs when two differing influenza viruses co-infect a cell. The viral diversity generated through reassortment is vast and plays an important role in the evolution of influenza viruses. Herein we review recent insights into the contribution of reassortment to the natural history and epidemiology of influenza A viruses, gained through population scale phylogenic analyses. We describe methods currently used to study reassortment in the laboratory, and we summarize recent progress made using these experimental approaches to further our understanding of influenza virus reassortment and the contexts in which it occurs.

  1. 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

  2. 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

  3. 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.

  4. Pseudotyping of vesicular stomatitis virus with the envelope glycoproteins of highly pathogenic avian influenza viruses.

    PubMed

    Zimmer, Gert; Locher, Samira; Berger Rentsch, Marianne; Halbherr, Stefan J

    2014-08-01

    Pseudotype viruses are useful for studying the envelope proteins of harmful viruses. This work describes the pseudotyping of vesicular stomatitis virus (VSV) with the envelope glycoproteins of highly pathogenic avian influenza viruses. VSV lacking the homotypic glycoprotein (G) gene (VSVΔG) was used to express haemagglutinin (HA), neuraminidase (NA) or the combination of both. Propagation-competent pseudotype viruses were only obtained when HA and NA were expressed from the same vector genome. Pseudotype viruses containing HA from different H5 clades were neutralized specifically by immune sera directed against the corresponding clade. Fast and sensitive reading of test results was achieved by vector-mediated expression of GFP. Pseudotype viruses expressing a mutant VSV matrix protein showed restricted spread in IFN-competent cells. This pseudotype system will facilitate the detection of neutralizing antibodies against virulent influenza viruses, circumventing the need for high-level biosafety containment.

  5. 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

  6. 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 ...

  7. Antigenic characterisation of influenza B virus with a new microneutralisation assay: comparison to haemagglutination and sequence analysis.

    PubMed

    Ansaldi, Filippo; Bacilieri, Sabrina; Amicizia, Daniela; Valle, Laura; Banfi, Federica; Durando, Paolo; Sticchi, Laura; Gasparini, Roberto; Icardi, Giancarlo; Crovari, Pietro

    2004-09-01

    Although the haemagglutination inhibition assay is considered the "gold standard" for antigenic characterisation of influenza viruses, some limitations of this technique are well known. A new microneutralisation assay, as a tool for antigenic characterisation of influenza B viruses, has been standardised and its performance evaluated in comparison with the haemagglutination inhibition test in the light of molecular characterisation of the haemagglutinin. Twelve B viruses belonging to the two lineages and the four sub-lineages discriminated by phylogenetic analysis of HA were tested. The microneutralisation assay clearly distinguishes viruses belonging to different lineages and, in addition, discriminates strains belonging to different sub-lineages that are poorly or not discriminated using the haemagglutination inhibition test. This new microneutralisation assay could provide a useful tool for antigenic characterisation of circulating influenza viruses and contribute, together with the haemagglutination inhibition test and sequence analysis of the haemagglutinin and neuraminidase, in the choice of the strain for use in vaccine composition.

  8. 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

  9. Evaluation of Haemagglutinin Content by RP-HPLC to Generate Pandemic Influenza Vaccine

    PubMed Central

    Kang, Hyunkyung; Roh, Hang Sik; Song, Hyemin; Lee, Kwangmoon; Chung, Seung-Tae; Ban, Sang-ja; Mo, In Pil; An, Beum-Soo; Ahn, Chi-Young

    2016-01-01

    The potency of influenza vaccine is determined based on its hemagglutinin (HA) content. In general, single radial immunodiffusion (SRID) assay has been utilized as the standard method to measure HA content. However, preparation of reagents for SRID such as antigen and antibody takes approximately 2~3 months, which causes delays in the development of influenza vaccine. Therefore, quantification of HA content by other alternative methods is required. In this study, we measured HA contents of H1N1 antigen and H1N1 influenza vaccine by reverse phase-high performance liquid chromatography (RP-HPLC) methods. The presence of HA1 and HA2 was investigated by silver staining and Western blot assay. In addition, accuracy and repeatability of HA measurement by RP-HPLC were evaluated. Comparison of HA concentration by SRID and RP-HPLC revealed a precise correlation between the two methods. Our results suggest that RP-HPLC assay can replace SRID in the event of a pandemic flu outbreak for rapid vaccine development.

  10. Review: influenza virus in pigs.

    PubMed

    Crisci, Elisa; Mussá, Tufária; Fraile, Lorenzo; Montoya, Maria

    2013-10-01

    Influenza virus disease still remains one of the major threats to human health, involving a wide range of animal species and pigs play an important role in influenza ecology. Pigs were labeled as "mixing vessels" since they are susceptible to infection with avian, human and swine influenza viruses and genetic reassortment between these viruses can occur. After the H1N1 influenza pandemic of 2009 with a swine origin virus, the most recent research in "influenzology" is directed at improving knowledge of porcine influenza virus infection. This tendency is probably due to the fact that domestic pigs are closely related to humans and represent an excellent animal model to study various microbial infectious diseases. In spite of the role of the pig in influenza virus ecology, swine immune responses against influenza viruses are not fully understood. Considering these premises, the aim of this review is to focus on the in vitro studies performed with porcine cells and influenza virus and on the immune responses of pigs against human, avian and swine influenza viruses in vivo. The increased acceptance of pigs as suitable and valuable models in the scientific community may stimulate the development of new tools to assess porcine immune responses, paving the way for their consideration as the future "gold standard" large-animal model in immunology.

  11. Responses of volunteers to inactivated influenza virus vaccines.

    PubMed Central

    Jennings, R.; Potter, C. W.; Massey, P. M.; Duerden, B. I.; Martin, J.; Bevan, A. M.

    1981-01-01

    Three different types of bivalent influenza virus vaccine, a whole virus, an aqueous-surface-antigen vaccine and an adsorbed-surface-antigen vaccine were tested at three dosage levels in volunteers primed with respect to only one of the haemagglutinin antigens present in the vaccines. The local and systemic reactions to all three vaccine types were mild in nature and, following first immunization, the aqueous-surface-antigen vaccine was the least reactogenic. The serum haemagglutination-inhibiting antibody response to the A/Victoria/75 component of the vaccines to which the volunteer population was primed, was greatest following immunization with the aqueous-surface-antigen vaccine; the greatest antibody response to the A/New Jersey/76 component of the vaccines was observed following immunization with whole virus vaccine. PMID:7007488

  12. Surveillance of influenza viruses isolated from travellers at Nagoya International Airport.

    PubMed Central

    Sato, K.; Morishita, T.; Nobusawa, E.; Suzuki, Y.; Miyazaki, Y.; Fukui, Y.; Suzuki, S.; Nakajima, K.

    2000-01-01

    In order to conduct a survey of influenza viruses entering Japan via travellers arriving by airplanes, gargle solutions were collected from passengers who reported to the quarantine station of Nagoya International Airport complaining of respiratory symptoms. From 504 samples collected between August 1996 and March 1999, 30 influenza virus strains were isolated. Twenty-eight of the isolates were influenza A (H3N2) viruses and two were influenza B viruses. No H1N1 virus was isolated. Among 28 isolates of H3N2 virus, 3 strains were obtained outside the influenza season. Nucleotide sequences of the haemagglutinin (HA) genes of these isolates along with those from domestic patients were analysed in order to determine the influence of imported influenza viruses by travellers on epidemics in Japan. From the phylogenetic and chronological aspects, the possibility was suggested in one case in 1997/8 and two in the 1998/9 season that imported virus by travellers may have influenced the domestic influenza epidemics. PMID:10982075

  13. 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

  14. 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

  15. 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. ...

  16. 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

  17. The genomic and epidemiological dynamics of human influenza A virus

    PubMed Central

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

    2008-01-01

    The evolutionary interaction between influenza A virus and the human immune system, manifest as ‘antigenic drift’ of the viral haemagglutinin, is one of the best described patterns in molecular evolution. However, little is known about the genome-scale evolutionary dynamics of this pathogen. Similarly, how genomic processes relate to global influenza epidemiology, in which the A/H3N2 and A/H1N1 subtypes co-circulate, is poorly understood. Here through an analysis of 1,302 complete viral genomes sampled from temperate populations in both hemispheres, we show that the genomic evolution of influenza A virus is characterized by a complex interplay between frequent reassortment and periodic selective sweeps. The A/H3N2 and A/H1N1 subtypes exhibit different evolutionary dynamics, with diverse lineages circulating in A/H1N1, indicative of weaker antigenic drift. These results suggest a sink-source model of viral ecology in which new lineages are seeded from a persistent influenza reservoir, which we hypothesize to be located in the tropics, to sink populations in temperate regions. PMID:18418375

  18. 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...

  19. Replication-incompetent influenza A viruses that stably express a foreign gene.

    PubMed

    Ozawa, Makoto; Victor, Sylvia T; Taft, Andrew S; Yamada, Shinya; Li, Chengjun; Hatta, Masato; Das, Subash C; Takashita, Emi; Kakugawa, Satoshi; Maher, Eileen A; Neumann, Gabriele; Kawaoka, Yoshihiro

    2011-12-01

    A biologically contained influenza A virus that stably expresses a foreign gene can be effectively traced, used to generate a novel multivalent vaccine and have its replication easily assessed, all while satisfying safety concerns regarding pathogenicity or reversion. This study generated a PB2-knockout (PB2-KO) influenza virus that harboured the GFP reporter gene in the coding region of its PB2 viral RNA (vRNA). Replication of the PB2-KO virus was restricted to a cell line stably expressing the PB2 protein. The GFP gene-encoding PB2 vRNA was stably incorporated into progeny viruses during replication in PB2-expressing cells. The GFP gene was expressed in virus-infected cells with no evidence of recombination between the recombinant PB2 vRNA and the PB2 protein mRNA. Furthermore, other reporter genes and the haemagglutinin and neuraminidase genes of different virus strains were accommodated by the PB2-KO virus. Finally, the PB2-KO virus was used to establish an improved assay to screen neutralizing antibodies against influenza viruses by using reporter gene expression as an indicator of virus infection rather than by observing cytopathic effect. These results indicate that the PB2-KO virus has the potential to be a valuable tool for basic and applied influenza virus research. PMID:21880840

  20. 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

  1. 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

  2. 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.

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

    PubMed

    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.

  4. 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

  5. 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.

  6. 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

  7. 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 ...

  8. Structure-guided discovery of potent and dual-acting human parainfluenza virus haemagglutinin-neuraminidase inhibitors.

    PubMed

    Guillon, Patrice; Dirr, Larissa; El-Deeb, Ibrahim M; Winger, Moritz; Bailly, Benjamin; Haselhorst, Thomas; Dyason, Jeffrey C; von Itzstein, Mark

    2014-01-01

    Human parainfluenza viruses (hPIVs) cause upper and lower respiratory tract disease in children that results in a significant number of hospitalizations and impacts health systems worldwide. To date, neither antiviral drugs nor vaccines are approved for clinical use against parainfluenza virus, which reinforces the urgent need for new therapeutic discovery strategies. Here we use a multidisciplinary approach to develop potent inhibitors that target a structural feature within the hPIV type 3 haemagglutinin-neuraminidase (hPIV-3 HN). These dual-acting designer inhibitors represent the most potent designer compounds and efficiently block both hPIV cell entry and virion progeny release. We also define the binding mode of these inhibitors in the presence of whole-inactivated hPIV and recombinantly expressed hPIV-3 HN by Saturation Transfer Difference NMR spectroscopy. Collectively, our study provides an antiviral preclinical candidate and a new direction towards the discovery of potential anti-parainfluenza drugs. PMID:25327774

  9. 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...

  10. Avian influenza virus and Newcastle disease virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) and Newcastle disease virus (NDV) severely impact poultry egg production. Decreased egg yield and hatchability, as well as misshapen eggs, are often observed during infection with AIV and NDV, even with low-virulence strains or in vaccinated flocks. Data suggest that in...

  11. Lack of transmission of a human influenza virus with avian receptor specificity between ferrets is not due to decreased virus shedding but rather a lower infectivity in vivo.

    PubMed

    Roberts, Kim L; Shelton, Holly; Scull, Margaret; Pickles, Raymond; Barclay, Wendy S

    2011-08-01

    Influenza virus attaches to host cells by sialic acid (SA). Human influenza viruses show preferential affinity for α2,6-linked SA, whereas avian influenza viruses bind α2,3-linked SA. In this study, mutation of the haemagglutinin receptor-binding site of a human H3N2 influenza A virus to switch binding to α2,3-linked SA did not eliminate infection of ferrets but prevented transmission, even in a co-housed model. The mutant virus was shed from the noses of ferrets directly inoculated with virus in the same amounts and for the same length of time as wild-type virus. Mutant virus infection was localized to the same anatomical regions of the upper respiratory tract of directly inoculated animals. Interestingly, wild-type virus was more readily neutralized than the mutant virus in vitro by ferret nasal washes containing mucus. Moreover after inoculation of equal doses, the mutant virus grew poorly in ex vivo ferret nasal turbinate tissue compared with wild-type virus. The dose of mutant virus required to establish infection in the directly inoculated ferrets was 40-fold higher than for wild-type virus. It was concluded that minimum infectious dose is a predictor of virus transmissibility and it is suggested that, as virus passes from one host to another through stringent environmental conditions, viruses with a preference for α2,3-linked SA are unlikely to inoculate a new mammalian host in sufficient quantities to initiate a productive infection.

  12. Antigenic analysis of highly pathogenic avian influenza virus H5N1 sublineages co-circulating in Egypt.

    PubMed

    Watanabe, Yohei; Ibrahim, Madiha S; Ellakany, Hany F; Kawashita, Norihito; Daidoji, Tomo; Takagi, Tatsuya; Yasunaga, Teruo; Nakaya, Takaaki; Ikuta, Kazuyoshi

    2012-10-01

    Highly pathogenic avian influenza virus H5N1 has spread across Eurasia and Africa, and outbreaks are now endemic in several countries, including Indonesia, Vietnam and Egypt. Continuous circulation of H5N1 virus in Egypt, from a single infected source, has led to significant genetic diversification with phylogenetically separable sublineages, providing an opportunity to study the impact of genetic evolution on viral phenotypic variation. In this study, we analysed the phylogeny of H5 haemagglutinin (HA) genes in influenza viruses isolated in Egypt from 2006 to 2011 and investigated the effect of conserved amino acid mutations in the HA genes in each of the sublineages on their antigenicity. The analysis showed that viruses in at least four sublineages still persisted in poultry in Egypt as of 2011. Using reverse genetics to generate HA-reassortment viruses with specific HA mutations, we found antigenic drift in the HA in two influenza virus sublineages, compared with the other currently co-circulating influenza virus sublineages in Egypt. Moreover, the two sublineages with significant antigenic drift were antigenically distinguishable. Our findings suggested that phylogenetically divergent H5N1 viruses, which were not antigenically cross-reactive, were co-circulating in Egypt, indicating that there was a problem in using a single influenza virus strain as seed virus to produce influenza virus vaccine in Egypt and providing data for designing more efficacious control strategies in H5N1-endemic areas.

  13. ATIVS: analytical tool for influenza virus surveillance.

    PubMed

    Liao, Yu-Chieh; Ko, Chin-Yu; Tsai, Ming-Hsin; Lee, Min-Shi; Hsiung, Chao A

    2009-07-01

    The WHO Global Influenza Surveillance Network has routinely performed genetic and antigenic analyses of human influenza viruses to monitor influenza activity. Although these analyses provide supporting data for the selection of vaccine strains, it seems desirable to have user-friendly tools to visualize the antigenic evolution of influenza viruses for the purpose of surveillance. To meet this need, we have developed a web server, ATIVS (Analytical Tool for Influenza Virus Surveillance), for analyzing serological data of all influenza viruses and hemagglutinin sequence data of human influenza A/H3N2 viruses so as to generate antigenic maps for influenza surveillance and vaccine strain selection. Functionalities are described and examples are provided to illustrate its usefulness and performance. The ATIVS web server is available at http://influenza.nhri.org.tw/ATIVS/.

  14. 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

  15. 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.

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

    PubMed

    Krammer, Florian

    2015-05-01

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

  17. 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

  18. 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

  19. Influenza: a virus of our times

    PubMed Central

    McCaughey, Conall

    2010-01-01

    Viruses are successful and omnipresent. Influenza A is a particularly important virus of humans. The article reviews the 2009 emergence of the pandemic influenza A virus, focusing on the potential origin of the virus and the distinctive clinical and epidemiological impact of the 2009 pandemic. PMID:21116418

  20. 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

  1. New vaccines against influenza virus.

    PubMed

    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; Kang, Sang-Moo

    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.

  2. 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 ...

  3. Strain-specific antiviral activity of iminosugars against human influenza A viruses

    PubMed Central

    Hussain, S.; Miller, J. L.; Harvey, D. J.; Gu, Y.; Rosenthal, P. B.; Zitzmann, N.; McCauley, J. W.

    2015-01-01

    Objectives Drugs that target host cell processes can be employed to complement drugs that specifically target viruses, and iminosugar compounds that inhibit host α-glucosidases have been reported to show antiviral activity against multiple viruses. Here the effect and mechanism of two iminosugar α-glucosidase inhibitors, N-butyl-deoxynojirimycin (NB-DNJ) and N-nonyl-deoxynojirimycin (NN-DNJ), on human influenza A viruses was examined. Methods The viruses examined were a recently circulating seasonal influenza A(H3N2) virus strain A/Brisbane/10/2007, an older H3N2 strain A/Udorn/307/72, and A/Lviv/N6/2009, a strain representative of the currently circulating pandemic influenza A(H1N1)pdm09 virus. Results The inhibitors had the strongest effect on Brisbane/10 and NN-DNJ was more potent than NB-DNJ. Both compounds showed antiviral activity in cell culture against three human influenza A viruses in a strain-specific manner. Consistent with its action as an α-glucosidase inhibitor, NN-DNJ treatment resulted in an altered glycan processing of influenza haemagglutinin (HA) and neuraminidase (NA), confirmed by MS. NN-DNJ treatment was found to reduce the cell surface expression of the H3 subtype HA. The level of sialidase activity of NA was reduced in infected cells, but the addition of exogenous sialidase to the cells did not complement the NN-DNJ-mediated inhibition of virus replication. Using reassortant viruses, the drug susceptibility profile was determined to correlate with the origin of the HA. Conclusions NN-DNJ inhibits influenza A virus replication in a strain-specific manner that is dependent on the HA. PMID:25223974

  4. 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

  5. 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

  6. Unusual Influenza A Viruses in Bats

    PubMed Central

    Mehle, Andrew

    2014-01-01

    Influenza A viruses infect a remarkably diverse number of hosts. Two completely new influenza A virus subtypes were recently discovered in bats, dramatically expanding the host range of the virus. These bat viruses are extremely divergent from all other known strains and likely have unique replication cycles. Phylogenetic analysis indicates long-term, isolated evolution in bats. This is supported by a high seroprevalence in sampled bat populations. As bats represent ~20% of all classified mammals, these findings suggests the presence of a massive cryptic reservoir of poorly characterized influenza A viruses. Here, we review the exciting progress made on understanding these newly discovered viruses, and discuss their zoonotic potential. PMID:25256392

  7. Reassortment patterns in Swine influenza viruses.

    PubMed

    Khiabanian, Hossein; Trifonov, Vladimir; Rabadan, Raul

    2009-10-07

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

  8. 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...

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

    PubMed

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

    2016-01-01

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

  10. 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

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

    PubMed

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

    2014-05-01

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

  12. 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

  13. [An overview on swine influenza viruses].

    PubMed

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

    2013-05-01

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

  14. 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

  15. 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

  16. 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

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

    PubMed

    De Vleeschauwer, Annebel; Van Reeth, Kristien

    2010-12-15

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

  18. Optimisation of a micro-neutralisation assay and its application in antigenic characterisation of influenza viruses

    PubMed Central

    Lin, Yipu; Gu, Yan; Wharton, Stephen A; Whittaker, Lynne; Gregory, Victoria; Li, Xiaoyan; Metin, Simon; Cattle, Nicholas; Daniels, Rodney S; Hay, Alan J; McCauley, John W

    2015-01-01

    Objectives The identification of antigenic variants and the selection of influenza viruses for vaccine production are based largely on antigenic characterisation of the haemagglutinin (HA) of circulating viruses using the haemagglutination inhibition (HI) assay. However, in addition to evolution related to escape from host immunity, variants emerging as a result of propagation in different cell substrates can complicate the interpretation of HI results. The objective was to develop further a micro-neutralisation (MN) assay to complement the HI assay in antigenic characterisation of influenza viruses to assess the emergence of new antigenic variants and reinforce the selection of vaccine viruses. Design and setting A 96-well-plate plaque reduction MN assay based on the measurement of infected cell population using a simple imaging technique. Sample Representative influenza A (H1N1) pdm09, A(H3N2) and B viruses isolated between 2004 and 2013 Main outcome measures and results Improvements to the plaque reduction MN assay included selection of the most suitable cell line according to virus type or subtype, and optimisation of experimental design and data quantitation. Comparisons of the results of MN and HI assays showed the importance of complementary data in determining the true antigenic relationships among recent human influenza A(H1N1)pdm09, A(H3N2) and type B viruses. Conclusions Our study demonstrates that the improved MN assay has certain advantages over the HI assay: it is not significantly influenced by the cell-selected amino acid substitutions in the neuraminidase (NA) of A(H3N2) viruses, and it is particularly useful for antigenic characterisation of viruses which either grow to low HA titre and/or undergo an abortive infection resulting in an inability to form plaques in cultured cells. PMID:26073976

  19. Visualizing influenza virus infection in living mice

    PubMed Central

    Pan, Weiqi; Dong, Zhenyuan; Li, Feng; Meng, Weixu; Feng, Liqiang; Niu, Xuefeng; Li, Chufang; Luo, Qinfang; Li, Zhengfeng; Sun, Caijun; Chen, Ling

    2013-01-01

    Preventing and treating influenza virus infection remain a challenge because of incomplete understanding of the host–pathogen interactions, limited therapeutics and lack of a universal vaccine. So far, methods for monitoring the course of infection with influenza virus in real time in living animals are lacking. Here we report the visualization of influenza viral infection in living mice using an engineered replication-competent influenza A virus carrying luciferase reporter gene. After intranasal inoculation, bioluminescence can be detected in the chest and nasopharyngeal passage of living mice. The intensity of bioluminescence in the chest correlates with the dosage of infection and the viral load in the lung. Bioluminescence in the chest of infected mice diminishes on antiviral treatment. This work provides a novel approach that enables real-time study of influenza virus infection and effects of antiviral therapeutics in living animals. PMID:24022374

  20. 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

  1. In vivo reassortment of influenza viruses.

    PubMed

    Urbaniak, Kinga; Markowska-Daniel, Iwona

    2014-01-01

    The genetic material of influenza A virus consists of eight negative-sense RNA segments. Under suitable conditions, the segmented structure of the viral genome allows an exchange of the individual gene segments between different strains, causing formation of new reassorted viruses. For reassortment to occur, co-infection with two or more influenza virus strains is necessary. The reassortment is an important evolutionary mechanism which can result in antigenic shifts that modify host range, pathology, and transmission of the influenza A viruses. In this process, the influenza virus strain with epidemic and/or pandemic potential can be created. Cases of this kind were in 1957 (Asian flu), 1968 (Hong Kong flu) and recently in 2009 (Mexico). Viruses containing genes of avian, swine, and/or human origin are widespread around the world, for example the triple reassortant H1N1 virus causing the 2009 influenza pandemic in 2009 that has become a seasonal virus. The aim of the study is to present the mechanism of reassortment and the results of experimental co-infection with different influenza viruses.

  2. 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

  3. Methamphetamine reduces human influenza A virus replication.

    PubMed

    Chen, Yun-Hsiang; Wu, Kuang-Lun; Chen, Chia-Hsiang

    2012-01-01

    Methamphetamine (meth) is a highly addictive psychostimulant that is among the most widely abused illicit drugs, with an estimated over 35 million users in the world. Several lines of evidence suggest that chronic meth abuse is a major factor for increased risk of infections with human immunodeficiency virus and possibly other pathogens, due to its immunosuppressive property. Influenza A virus infections frequently cause epidemics and pandemics of respiratory diseases among human populations. However, little is known about whether meth has the ability to enhance influenza A virus replication, thus increasing severity of influenza illness in meth abusers. Herein, we investigated the effects of meth on influenza A virus replication in human lung epithelial A549 cells. The cells were exposed to meth and infected with human influenza A/WSN/33 (H1N1) virus. The viral progenies were titrated by plaque assays, and the expression of viral proteins and cellular proteins involved in interferon responses was examined by Western blotting and immunofluorescence staining. We report the first evidence that meth significantly reduces, rather than increases, virus propagation and the susceptibility to influenza infection in the human lung epithelial cell line, consistent with a decrease in viral protein synthesis. These effects were apparently not caused by meth's effects on enhancing virus-induced interferon responses in the host cells, reducing viral biological activities, or reducing cell viability. Our results suggest that meth might not be a great risk factor for influenza A virus infection among meth abusers. Although the underlying mechanism responsible for the action of meth on attenuating virus replication requires further investigation, these findings prompt the study to examine whether other structurally similar compounds could be used as anti-influenza agents.

  4. History of Swine influenza viruses in Asia.

    PubMed

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

    2013-01-01

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

  5. H7N9 Influenza Virus Is More Virulent in Ferrets than 2009 Pandemic H1N1 Influenza Virus.

    PubMed

    Yum, Jung; Ku, Keun Bon; Kim, Hyun Soo; Seo, Sang Heui

    2015-12-01

    The novel H7N9 influenza virus has been infecting humans in China since February 2013 and with a mortality rate of about 40%. This study compared the pathogenicity of the H7N9 and 2009 pandemic H1N1 influenza viruses in a ferret model, which shows similar symptoms to those of humans infected with influenza viruses. The H7N9 influenza virus caused a more severe disease than did the 2009 pandemic H1N1 influenza virus. All of the ferrets infected with the H7N9 influenza virus had died by 6 days after infection, while none of those infected with the 2009 pandemic H1N1 influenza virus died. Ferrets infected with the H7N9 influenza virus had higher viral titers in their lungs than did those infected with the 2009 pandemic H1N1 influenza virus. Histological findings indicated that hemorrhagic pneumonia was caused by infection with the H7N9 influenza virus, but not with the 2009 pandemic H1N1 influenza virus. In addition, the lung tissues of ferrets infected with the H7N9 influenza virus contained higher levels of chemokines than did those of ferrets infected with the 2009 pandemic H1N1 influenza virus. This study suggests that close monitoring is needed to prevent human infection by the lethal H7N9 influenza virus.

  6. 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

  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. 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.

  9. Knowns and unknowns of influenza B viruses.

    PubMed

    Koutsakos, Marios; Nguyen, Thi H O; Barclay, Wendy S; Kedzierska, Katherine

    2016-01-01

    Influenza B viruses (IBVs) circulate annually along with influenza A (IAV) strains during seasonal epidemics. IBV can dominate influenza seasons and cause severe disease, particularly in children and adolescents. Research has revealed interesting aspects of IBV and highlighted the importance of these viruses in clinical settings. Yet, many important questions remain unanswered. In this review, the clinical relevance of IBV is emphasized, unique features in epidemiology, host range and virology are highlighted and gaps in knowledge pinpointed. Multiple aspects of IBV epidemiology, evolution, virology and immunology are discussed. Future research into IBV is needed to understand how we can prevent severe disease in high-risk groups, especially children and elderly.

  10. 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

  11. Preservation of Influenza Virus Infectivity by Lyophilization

    PubMed Central

    Beardmore, W. B.; Clark, T. D.; Jones, K. V.

    1968-01-01

    A method of lyophilizing influenza virus in allantoic fluid with retention of high-titer of egg infectivity is described. Five strains of virus were lyophilized, and all were much more stable than fluid virus preparations, retaining 2 to 3 logs of infectivity after storage at 37 C for 60 to 95 days. Statistical analysis of an accelerated storage test by extrapolation of viral degradation indicates that the lyophilized viruses are stable indefinitely at or below room temperature. PMID:5645420

  12. Rapid genotyping of swine influenza viruses.

    PubMed

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

    2011-04-01

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

  13. Rapid Genotyping of Swine Influenza Viruses

    PubMed Central

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

    2011-01-01

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

  14. 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

  15. 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

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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 ...

  20. 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.

  1. 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

  2. Rapid and sensitive detection of avian influenza virus subtype H7 using NASBA.

    PubMed

    Collins, Richard A; Ko, Lung-Sang; Fung, King-Yip; Chan, Ka-Yun; Xing, Jun; Lau, Lok-Ting; Yu, Albert Cheung Hoi

    2003-01-10

    Nucleic acid sequence-based amplification with electrochemiluminescent detection (NASBA/ECL) is an isothermal technique allowing rapid amplification and detection of specific regions of nucleic acid from a diverse range of sources. It is especially suitable for amplifying RNA. A NASBA/ECL technique has been developed allowing the detection of RNA from avian influenza virus subtype H7 derived from allantoic fluid harvested from inoculated chick embryos and from cell cultures. Degenerate amplification primers and amplicon capture probes were designed enabling the detection of low and highly pathogenic avian influenza of the H7 subtype from the Eurasian and North American lineages and the Australian sub-lineage. The NASBA/ECL technique is specific for subtype H7 and does not cross-react with other influenza subtypes or with viruses containing haemagglutinin-like genes. The assay is 10- to 100-fold more sensitive than a commercially available antigen capture immunoassay system. The NASBA/ECL assay could be used in high throughput poultry screening programmes.

  3. 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% ...

  4. Structural basis for preferential avian receptor binding by the human-infecting H10N8 avian influenza virus.

    PubMed

    Wang, Min; Zhang, Wei; Qi, Jianxun; Wang, Fei; Zhou, Jianfang; Bi, Yuhai; Wu, Ying; Sun, Honglei; Liu, Jinhua; Huang, Chaobin; Li, Xiangdong; Yan, Jinghua; Shu, Yuelong; Shi, Yi; Gao, George F

    2015-01-01

    Since December 2013, at least three cases of human infections with H10N8 avian influenza virus have been reported in China, two of them being fatal. To investigate the epidemic potential of H10N8 viruses, we examined the receptor binding property of the first human isolate, A/Jiangxi-Donghu/346/2013 (JD-H10N8), and determined the structures of its haemagglutinin (HA) in complex with both avian and human receptor analogues. Our results suggest that JD-H10N8 preferentially binds the avian receptor and that residue R137-localized within the receptor-binding site of HA-plays a key role in this preferential binding. Compared with the H7N9 avian influenza viruses, JD-H10N8 did not exhibit the enhanced binding to human receptors observed with the prevalent H7N9 virus isolate Anhui-1, but resembled the receptor binding activity of the early-outbreak H7N9 isolate (Shanghai-1). We conclude that the H10N8 virus is a typical avian influenza virus.

  5. 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

  6. Swine influenza viruses: an Asian perspective.

    PubMed

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

    2013-01-01

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

  7. 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

  8. 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

  9. Nasal commensal Staphylococcus epidermidis counteracts influenza virus.

    PubMed

    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

    2016-06-16

    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.

  10. 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

  11. 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.

  12. 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

  13. The genome of an influenza virus from a pilot whale: relation to influenza viruses of gulls and marine mammals.

    PubMed

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

    2014-06-01

    Influenza virus A/whale/Maine/328B/1984 (H13N2) was isolated from a diseased pilot whale. Since only a partial sequence was available, its complete genome was sequenced and compared to the sequences of subtype H13 influenza viruses from shorebirds and various influenza viruses of marine mammals. The data reveal a rare genotype constellation with all gene segments derived of an influenza virus adapted to gulls, terns and waders. In contrast, the phylogenetic trees indicate that the majority of influenza viruses isolated from marine mammals derived from influenza viruses adapted to geese and ducks. We conclude that A/whale/Maine/328B/1984 is the first record of an infection of a marine mammal from a gull-origin influenza virus. PMID:24704761

  14. 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...

  15. Phenolic Diterpenoid Derivatives as Anti-Influenza A Virus Agents

    PubMed Central

    2015-01-01

    A series of diterpenoid derivatives based on podocarpic acid were synthesized and evaluated as anti-influenza A virus agents. Several of the novel podocarpic acid derivatives exhibited nanomolar activities against an H1N1 influenza A virus (A/Puerto Rico/8/34) that was resistant to two anti-influenza drugs, oseltamivir and amantadine. This class of compounds inhibits the influenza virus by targeting the viral hemagglutinin-mediated membrane fusion. These results indicated that podocarpic acid derivatives may serve as potential drug candidates to fight drug-resistant influenza A virus infections. PMID:25815159

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

    PubMed

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

    2011-01-01

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

  17. 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.

  18. Adaptive mutation in nuclear export protein allows stable transgene expression in a chimaeric influenza A virus vector.

    PubMed

    Kuznetsova, Irina; Shurygina, Anna-Polina; Wolf, Brigitte; Wolschek, Markus; Enzmann, Florian; Sansyzbay, Abylay; Khairullin, Berik; Sandybayev, Nurlan; Stukova, Marina; Kiselev, Oleg; Egorov, Andrej; Bergmann, Michael

    2014-02-01

    The development of influenza virus vectors with long insertions of foreign sequences remains difficult due to the small size and instable nature of the virus. Here, we used the influenza virus inherent property of self-optimization to generate a vector stably expressing long transgenes from the NS1 protein ORF. This was achieved by continuous selection of bright fluorescent plaques of a GFP-expressing vector during multiple passages in mouse B16f1 cells. The newly generated vector acquired stability in IFN-competent cell lines and in vivo in murine lungs. Although improved vector fitness was associated with the appearance of four coding mutations in the polymerase (PB2), haemagglutinin and non-structural (NS) segments, the stability of the transgene expression was dependent primarily on the single mutation Q20R in the nuclear export protein (NEP). Importantly, a longer insert, such as a cassette of 1299 nt encoding two Mycobacterium tuberculosis Esat6 and Ag85A proteins, could substitute for the GFP transgene. Thus, the inherent property of the influenza virus to adapt can also be used to adjust a vector backbone to give stable expression of long transgenes. PMID:24222196

  19. Novel Polyanions Inhibiting Replication of Influenza Viruses

    PubMed Central

    Ciejka, Justyna; Milewska, Aleksandra; Wytrwal, Magdalena; Wojarski, Jacek; Golda, Anna; Ochman, Marek; Nowakowska, Maria

    2016-01-01

    Novel sulfonated derivatives of poly(allylamine hydrochloride) (NSPAHs) and N-sulfonated chitosan (NSCH) have been synthesized, and their activity against influenza A and B viruses has been studied and compared with that of a series of carrageenans, marine polysaccharides of well-documented anti-influenza activity. NSPAHs were found to be nontoxic and very soluble in water, in contrast to gel-forming and thus generally poorly soluble carrageenans. In vitro and ex vivo studies using susceptible cells (Madin-Darby canine kidney epithelial cells and fully differentiated human airway epithelial cultures) demonstrated the antiviral effectiveness of NSPAHs. The activity of NSPAHs was proportional to the molecular mass of the chain and the degree of substitution of amino groups with sulfonate groups. Mechanistic studies showed that the NSPAHs and carrageenans inhibit influenza A and B virus assembly in the cell. PMID:26729490

  20. Circulating avian influenza viruses closely related to the 1918 virus have pandemic potential.

    PubMed

    Watanabe, Tokiko; Zhong, Gongxun; Russell, Colin A; Nakajima, Noriko; Hatta, Masato; Hanson, Anthony; McBride, Ryan; Burke, David F; Takahashi, Kenta; Fukuyama, Satoshi; Tomita, Yuriko; Maher, Eileen A; Watanabe, Shinji; Imai, Masaki; Neumann, Gabriele; Hasegawa, Hideki; Paulson, James C; Smith, Derek J; Kawaoka, Yoshihiro

    2014-06-11

    Wild birds harbor a large gene pool of influenza A viruses that have the potential to cause influenza pandemics. Foreseeing and understanding this potential is important for effective surveillance. Our phylogenetic and geographic analyses revealed the global prevalence of avian influenza virus genes whose proteins differ only a few amino acids from the 1918 pandemic influenza virus, suggesting that 1918-like pandemic viruses may emerge in the future. To assess this risk, we generated and characterized a virus composed of avian influenza viral segments with high homology to the 1918 virus. This virus exhibited pathogenicity in mice and ferrets higher than that in an authentic avian influenza virus. Further, acquisition of seven amino acid substitutions in the viral polymerases and the hemagglutinin surface glycoprotein conferred respiratory droplet transmission to the 1918-like avian virus in ferrets, demonstrating that contemporary avian influenza viruses with 1918 virus-like proteins may have pandemic potential. PMID:24922572

  1. Circulating avian influenza viruses closely related to the 1918 virus have pandemic potential

    PubMed Central

    Watanabe, Tokiko; Zhong, Gongxun; Russell, Colin A.; Nakajima, Noriko; Hatta, Masato; Hanson, Anthony; McBride, Ryan; Burke, David F.; Takahashi, Kenta; Fukuyama, Satoshi; Tomita, Yuriko; Maher, Eileen A.; Watanabe, Shinji; Imai, Masaki; Neumann, Gabriele; Hasegawa, Hideki; Paulson, James C.; Smith, Derek J.; Kawaoka, Yoshihiro

    2014-01-01

    Summary Wild birds harbor a large gene pool of influenza A viruses that have the potential to cause influenza pandemics. Foreseeing and understanding this potential is important for effective surveillance. Our phylogenetic and geographic analyses revealed the global prevalence of avian influenza virus genes whose proteins differ only a few amino acids from the 1918 pandemic influenza virus, suggesting that 1918-like pandemic viruses may emerge in the future. To assess this risk, we generated and characterized a virus composed of avian influenza viral segments with high homology to the 1918 virus. This virus exhibited higher pathogenicity in mice and ferrets than an authentic avian influenza virus. Further, acquisition of seven amino acid substitutions in the viral polymerases and the hemagglutinin surface glycoprotein conferred respiratory droplet transmission to the 1918-like avian virus in ferrets, demonstrating that contemporary avian influenza viruses with 1918 virus-like proteins may have pandemic potential. PMID:24922572

  2. Influenza viruses and the evolution of avian influenza virus H5N1.

    PubMed

    Skeik, Nedaa; Jabr, Fadi I

    2008-05-01

    Although small in size and simple in structure, influenza viruses are sophisticated organisms with highly mutagenic genomes and wide antigenic diversity. They are species-specific organisms. Mutation and reassortment have resulted in newer viruses such as H5N1, with new resistance against anti-viral medications, and this might lead to the emergence of a fully transmissible strain, as occurred in the 1957 and 1968 pandemics. Influenza viruses are no longer just a cause of self-limited upper respiratory tract infections; the H5N1 avian influenza virus can cause severe human infection with a mortality rate exceeding 50%. The case death rate of H5N1 avian influenza infection is 20 times higher than that of the 1918 infection (50% versus 2.5%), which killed 675000 people in the USA and almost 40 million people worldwide. While the clock is still ticking towards what seems to be inevitable pandemic influenza, on April 17, 2007 the U.S. Food and Drug Administration (FDA) approved the first vaccine against the avian influenza virus H5N1 for humans at high risk. However, more research is needed to develop a more effective and affordable vaccine that can be given at lower doses.

  3. 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.

  4. Isolation of a Novel Swine Influenza Virus from Oklahoma in 2011 Which Is Distantly Related to Human Influenza C Viruses

    PubMed Central

    Hause, Ben M.; Ducatez, Mariette; Collin, Emily A.; Ran, Zhiguang; Liu, Runxia; Sheng, Zizhang; Armien, Anibal; Kaplan, Bryan; Chakravarty, Suvobrata; Hoppe, Adam D.; Webby, Richard J.; Simonson, Randy R.; Li, Feng

    2013-01-01

    Of the Orthomyxoviridae family of viruses, only influenza A viruses are thought to exist as multiple subtypes and has non-human maintenance hosts. In April 2011, nasal swabs were collected for virus isolation from pigs exhibiting influenza-like illness. Subsequent electron microscopic, biochemical, and genetic studies identified an orthomyxovirus with seven RNA segments exhibiting approximately 50% overall amino acid identity to human influenza C virus. Based on its genetic organizational similarities to influenza C viruses this virus has been provisionally designated C/Oklahoma/1334/2011 (C/OK). Phylogenetic analysis of the predicted viral proteins found that the divergence between C/OK and human influenza C viruses was similar to that observed between influenza A and B viruses. No cross reactivity was observed between C/OK and human influenza C viruses using hemagglutination inhibition (HI) assays. Additionally, screening of pig and human serum samples found that 9.5% and 1.3%, respectively, of individuals had measurable HI antibody titers to C/OK virus. C/OK virus was able to infect both ferrets and pigs and transmit to naive animals by direct contact. Cell culture studies showed that C/OK virus displayed a broader cellular tropism than a human influenza C virus. The observed difference in cellular tropism was further supported by structural analysis showing that hemagglutinin esterase (HE) proteins between two viruses have conserved enzymatic but divergent receptor-binding sites. These results suggest that C/OK virus represents a new subtype of influenza C viruses that currently circulates in pigs that has not been recognized previously. The presence of multiple subtypes of co-circulating influenza C viruses raises the possibility of reassortment and antigenic shift as mechanisms of influenza C virus evolution. PMID:23408893

  5. Isolation of a novel swine influenza virus from Oklahoma in 2011 which is distantly related to human influenza C viruses.

    PubMed

    Hause, Ben M; Ducatez, Mariette; Collin, Emily A; Ran, Zhiguang; Liu, Runxia; Sheng, Zizhang; Armien, Anibal; Kaplan, Bryan; Chakravarty, Suvobrata; Hoppe, Adam D; Webby, Richard J; Simonson, Randy R; Li, Feng

    2013-02-01

    Of the Orthomyxoviridae family of viruses, only influenza A viruses are thought to exist as multiple subtypes and has non-human maintenance hosts. In April 2011, nasal swabs were collected for virus isolation from pigs exhibiting influenza-like illness. Subsequent electron microscopic, biochemical, and genetic studies identified an orthomyxovirus with seven RNA segments exhibiting approximately 50% overall amino acid identity to human influenza C virus. Based on its genetic organizational similarities to influenza C viruses this virus has been provisionally designated C/Oklahoma/1334/2011 (C/OK). Phylogenetic analysis of the predicted viral proteins found that the divergence between C/OK and human influenza C viruses was similar to that observed between influenza A and B viruses. No cross reactivity was observed between C/OK and human influenza C viruses using hemagglutination inhibition (HI) assays. Additionally, screening of pig and human serum samples found that 9.5% and 1.3%, respectively, of individuals had measurable HI antibody titers to C/OK virus. C/OK virus was able to infect both ferrets and pigs and transmit to naive animals by direct contact. Cell culture studies showed that C/OK virus displayed a broader cellular tropism than a human influenza C virus. The observed difference in cellular tropism was further supported by structural analysis showing that hemagglutinin esterase (HE) proteins between two viruses have conserved enzymatic but divergent receptor-binding sites. These results suggest that C/OK virus represents a new subtype of influenza C viruses that currently circulates in pigs that has not been recognized previously. The presence of multiple subtypes of co-circulating influenza C viruses raises the possibility of reassortment and antigenic shift as mechanisms of influenza C virus evolution.

  6. Using Sequence Data To Infer the Antigenicity of Influenza Virus

    PubMed Central

    Sun, Hailiang; Yang, Jialiang; Zhang, Tong; Long, Li-Ping; Jia, Kun; Yang, Guohua; Webby, Richard J.; Wan, Xiu-Feng

    2013-01-01

    ABSTRACT The efficacy of current influenza vaccines requires a close antigenic match between circulating and vaccine strains. As such, timely identification of emerging influenza virus antigenic variants is central to the success of influenza vaccination programs. Empirical methods to determine influenza virus antigenic properties are time-consuming and mid-throughput and require live viruses. Here, we present a novel, experimentally validated, computational method for determining influenza virus antigenicity on the basis of hemagglutinin (HA) sequence. This method integrates a bootstrapped ridge regression with antigenic mapping to quantify antigenic distances by using influenza HA1 sequences. Our method was applied to H3N2 seasonal influenza viruses and identified the 13 previously recognized H3N2 antigenic clusters and the antigenic drift event of 2009 that led to a change of the H3N2 vaccine strain. PMID:23820391

  7. Serological and virological surveillance of avian influenza A virus H9N2 subtype in humans and poultry in Shanghai, China, between 2008 and 2010.

    PubMed

    Wang, Q; Ju, L; Liu, P; Zhou, J; Lv, X; Li, L; Shen, H; Su, H; Jiang, L; Jiang, Q

    2015-03-01

    We report the serological evidence of low-pathogenic avian influenza (LPAI) H9N2 infection in an occupational poultry-exposed population and a general population. A serological survey of an occupational poultry-exposed population and a general population was conducted using a haemagglutinin-inhibiting (HI) assay in Shanghai, China, from January 2008 to December 2010. Evidence of higher anti-H9 antibodies was found in serum samples collected from poultry workers. During this period, 239 H9N2 avian influenza viruses (AIVs) were isolated from 9297 tracheal and cloacal paired specimens collected from the poultry in live poultry markets. In addition, a total of 733 influenza viruses were isolated from 1569 nasal and throat swabs collected from patients with influenza-like symptoms in a sentinel hospital, which include H3N2, H1N1, pandemic H1N1 and B, but no H9N2 virus was detected. These findings highlight the need for long-term surveillance of avian influenza viruses in occupational poultry-exposed workers.

  8. Serological and Virological Surveillance of Avian Influenza A Virus H9N2 Subtype in Humans and Poultry in Shanghai, China, Between 2008 and 2010

    PubMed Central

    Wang, Q; Ju, L; Liu, P; Zhou, J; Lv, X; Li, L; Shen, H; Su, H; Jiang, L; Jiang, Q

    2015-01-01

    We report the serological evidence of low-pathogenic avian influenza (LPAI) H9N2 infection in an occupational poultry-exposed population and a general population. A serological survey of an occupational poultry-exposed population and a general population was conducted using a haemagglutinin-inhibiting (HI) assay in Shanghai, China, from January 2008 to December 2010. Evidence of higher anti-H9 antibodies was found in serum samples collected from poultry workers. During this period, 239 H9N2 avian influenza viruses (AIVs) were isolated from 9297 tracheal and cloacal paired specimens collected from the poultry in live poultry markets. In addition, a total of 733 influenza viruses were isolated from 1569 nasal and throat swabs collected from patients with influenza-like symptoms in a sentinel hospital, which include H3N2, H1N1, pandemic H1N1 and B, but no H9N2 virus was detected. These findings highlight the need for long-term surveillance of avian influenza viruses in occupational poultry-exposed workers. PMID:24803167

  9. 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

  10. A brief introduction to avian influenza virus.

    PubMed

    Spackman, Erica

    2014-01-01

    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 1870s, and avian influenza has been recognized in domestic poultry through the modern era of poultry production. Approaches to control vary widely, but elimination of the disease in poultry is a common goal. The basics of AIV biology, clinical disease, molecular aspects, and AIV detection are briefly reviewed. PMID:24899420

  11. 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...

  12. The Little Ice Age and the emergence of influenza A.

    PubMed

    Gatherer, Derek

    2010-10-01

    Bayesian phylogenetic analysis of the haemagglutinin and neuraminidase proteins of influenza A virus demonstrates that their respective most recent common ancestors (MRCAs) both existed approximately 1000years ago. Most of the bifurcations within the haemagglutinin and neuraminidase phylogenetic trees occurred within a time window that can be dated with 95% confidence to the years 1411-1932 of the Common Era (AD) for haemagglutinin and 1366-1874 AD for neuraminidase. This subtype diversification episode is temporally congruent with the "Little Ice Age", a period of climatic cooling over the northern hemisphere. Furthermore, Bayesian probability mean ages for the bifurcation points within the haemagglutinin tree indicate two bursts of diversification from 1672 to 1715 AD and from 1825 to 1868 AD. The first of these follows in the wake of the coldest epoch in the Little Ice Age, and the second overlaps a later cooling episode. Since climate change is known to affect migration patterns in the reservoir host of influenza A, the aquatic wildfowl, and allopatric cladogenesis following population disruption is well supported in the evolutionary literature, a mechanism is proposed linking the Little Ice Age to influenza subtype diversification via ecological disruption of the wildfowl annual cycle. The suggestion that past climate change has impacted on influenza evolution implies that current global warming may cause a further burst of influenza subtype diversification with possible serious epidemiological consequences becoming apparent in the 22nd and 23rd centuries.

  13. 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

  14. 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.

  15. Phylogenetic analysis of the haemagglutinin gene of current wild-type canine distemper viruses from South Africa: lineage Africa.

    PubMed

    Woma, Timothy Y; van Vuuren, Moritz; Bosman, Ana-Mari; Quan, Melvyn; Oosthuizen, Marinda

    2010-07-14

    There are no reports of CDV isolations in southern Africa, and although CDV is said to have geographically distinct lineages, molecular information of African strains has not yet been documented. Viruses isolated in cell cultures were subjected to reverse transcription-polymerase chain reaction (RT-PCR), and the complete H gene was sequenced and phylogenetically analysed with other strains from GenBank. Phylogenetic comparisons of the complete H gene of CDV isolates from different parts of the world (available in GenBank) with wild-type South African isolates revealed nine clades. All South African isolates form a separate African clade of their own and thus are clearly separated from the American, European, Asian, Arctic and vaccine virus clades. It is likely that only the 'African lineage' of CDV may be circulating in South Africa currently, and the viruses isolated from dogs vaccinated against CDV are not the result of reversion to virulence of vaccine strains, but infection with wild-type strains.

  16. DIVA vaccination strategies for avian influenza virus.

    PubMed

    Suarez, David L

    2012-12-01

    Vaccination for both low pathogenicity avian influenza and highly pathogenic avian influenza is commonly used by countries that have become endemic for avian influenza virus, but stamping-out policies are still common for countries with recently introduced disease. Stamping-out policies of euthanatizing infected and at-risk flocks has been an effective control tool, but it comes at a high social and economic cost. Efforts to identify alternative ways to respond to outbreaks without widespread stamping out has become a goal for organizations like the World Organisation for Animal Health. A major issue with vaccination for avian influenza is trade considerations because countries that vaccinate are often considered to be endemic for the disease and they typically lose their export markets. Primarily as a tool to promote trade, the concept of DIVA (differentiate infected from vaccinated animals) has been considered for avian influenza, but the goal for trade is to differentiate vaccinated and not-infected from vaccinated and infected animals because trading partners are unwilling to accept infected birds. Several different strategies have been investigated for a DIVA strategy, but each has advantages and disadvantages. A review of current knowledge on the research and implementation of the DIVA strategy will be discussed with possible ways to implement this strategy in the field. The increased desire for a workable DIVA strategy may lead to one of these ideas moving from the experimental to the practical.

  17. Epidemiological Dynamics and Phylogeography of Influenza Virus in Southern China

    PubMed Central

    Cheng, Xiaowen; Tan, Yi; He, Mingliang; Lam, Tommy Tsan-Yuk; Lu, Xing; Viboud, Cécile; He, Jianfan; Zhang, Shunxiang; Lu, Jianhua; Wu, Chunli; Fang, Shishong; Wang, Xin; Xie, Xu; Ma, Hanwu; Nelson, Martha I.; Kung, Hsiang-fu; Holmes, Edward C.; Cheng, Jinquan

    2013-01-01

    Background. Understanding the epidemiological dynamics of influenza virus is central to surveillance and vaccine strain selection. It has been suggested that tropical and subtropical regions represent the global source of influenza epidemics. However, our understanding of the epidemiological dynamics of influenza virus in these regions is limited by a relative lack of long-term data. Methods. We analyzed epidemiological and virological data on influenza recorded over a period of 15 years from the metropolitan city of Shenzhen in subtropical southern China. We used wavelet analysis to determine the periodicity of influenza epidemics and molecular phylogeographic analysis to investigate the role of Shenzhen and southern China in the global evolution of influenza virus. Results. We show that southern China is unlikely to represent an epicenter of global influenza activity, because activity in Shenzhen is characterized by significant annual cycles, multiple viral introductions every year, limited persistence across epidemic seasons, and viruses that generally are not positioned on the trunk of the global influenza virus phylogeny. Conclusions. We propose that novel influenza viruses emerge and evolve in multiple geographic localities and that the global evolution of influenza virus is complex and does not simply originate from a southern Chinese epicenter. PMID:22930808

  18. Human influenza A viruses isolated in South America: genetic relations, adamantane resistance and vaccine strain match.

    PubMed

    Goñi, Natalia; Russi, José; Cristina, Juan

    2009-03-01

    In order to gain insight into the genetic relations among H3N2 Influenza A virus (IAV) circulating in the South American region from 1999 to 2007, to investigate the presence of adamantane-resistant strains in this region, and to establish the genetic relations among that strains and vaccine strains recommended for the Southern hemisphere, 11 haemagglutinin (HA) H3 IAV sequences obtained from Uruguayan patients were aligned with corresponding sequences from 68 H3 IAV strains isolated in South America and 9 H3 IAV vaccine strains. Maximum likelihood phylogenetic tree analysis was performed using the GTR evolutionary model. The results of these studies indicate that multiple clades co-circulate during most influenza seasons in South America. Strikingly, one strain isolated in Uruguay in 2005 and all strains isolated in that country during the 2007 season bear an HA adamantane-resistant polymorphism. No other strain isolated in South America previous to the 2005 season bears that HA characteristic amino acid change. Only vaccine strains recommended for the 2007 season were assigned to the same cluster with all available IAV isolated in South America for that season. Evolution of IAV in this region appears to be shaped by re-introduction of new strains.

  19. 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

  20. 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.

  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. 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

  3. Molecular evolution of H5N1 highly pathogenic avian influenza viruses in Bangladesh between 2007 and 2012.

    PubMed

    Haque, M E; Giasuddin, M; Chowdhury, E H; Islam, M R

    2014-01-01

    In Bangladesh, highly pathogenic avian influenza (HPAI) virus subtype H5N1 was first detected in February 2007. Since then the virus has become entrenched in poultry farms of Bangladesh. There have so far been seven human cases of H5N1 HPAI infection in Bangladesh with one death. The objective of the present study was to investigate the molecular evolution of H5N1 HPAI viruses during 2007 to 2012. Partial or complete nucleotide sequences of all eight gene segments of two chicken isolates, five gene segments of a duck isolate and the haemagglutinin gene segment of 18 isolates from Bangladesh were established in the present study and subjected to molecular analysis. In addition, full-length sequences of different gene segments of other Bangladeshi H5N1 isolates available in GenBank were included in the analysis. The analysis revealed that the first introduction of clade 2.2 virus in Bangladesh in 2007 was followed by the introduction of clade 2.3.2.1 and 2.3.4 viruses in 2011. However, only clade 2.3.2.1 viruses could be isolated in 2012, indicating progressive replacement of clade 2.2 and 2.3.4 viruses. There has been an event of segment re-assortment between H5N1 and H9N2 viruses in Bangladesh, where H5N1 virus acquired the PB1 gene from a H9N2 virus. Point mutations have accumulated in Bangladeshi isolates over the last 5 years with potential modification of receptor binding site and antigenic sites. Extensive and continuous molecular epidemiological studies are necessary to monitor the evolution of circulating avian influenza viruses in Bangladesh.

  4. Characterization of uncultivable bat influenza virus using a replicative synthetic virus.

    PubMed

    Zhou, Bin; Ma, Jingjiao; Liu, Qinfang; Bawa, Bhupinder; Wang, Wei; Shabman, Reed S; Duff, Michael; Lee, Jinhwa; Lang, Yuekun; Cao, Nan; Nagy, Abdou; Lin, Xudong; Stockwell, Timothy B; Richt, Juergen A; Wentworth, David E; Ma, Wenjun

    2014-10-01

    Bats harbor many viruses, which are periodically transmitted to humans resulting in outbreaks of disease (e.g., Ebola, SARS-CoV). Recently, influenza virus-like sequences were identified in bats; however, the viruses could not be cultured. This discovery aroused great interest in understanding the evolutionary history and pandemic potential of bat-influenza. Using synthetic genomics, we were unable to rescue the wild type bat virus, but could rescue a modified bat-influenza virus that had the HA and NA coding regions replaced with those of A/PR/8/1934 (H1N1). This modified bat-influenza virus replicated efficiently in vitro and in mice, resulting in severe disease. Additional studies using a bat-influenza virus that had the HA and NA of A/swine/Texas/4199-2/1998 (H3N2) showed that the PR8 HA and NA contributed to the pathogenicity in mice. Unlike other influenza viruses, engineering truncations hypothesized to reduce interferon antagonism into the NS1 protein didn't attenuate bat-influenza. In contrast, substitution of a putative virulence mutation from the bat-influenza PB2 significantly attenuated the virus in mice and introduction of a putative virulence mutation increased its pathogenicity. Mini-genome replication studies and virus reassortment experiments demonstrated that bat-influenza has very limited genetic and protein compatibility with Type A or Type B influenza viruses, yet it readily reassorts with another divergent bat-influenza virus, suggesting that the bat-influenza lineage may represent a new Genus/Species within the Orthomyxoviridae family. Collectively, our data indicate that the bat-influenza viruses recently identified are authentic viruses that pose little, if any, pandemic threat to humans; however, they provide new insights into the evolution and basic biology of influenza viruses.

  5. 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.

  6. 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

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

    PubMed

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

    2012-11-01

    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.

  8. The anti-influenza virus effect of Phellinus igniarius extract.

    PubMed

    Lee, Sangmoo; Kim, Jin Il; Heo, Jun; Lee, Ilseob; Park, Sehee; Hwang, Min-Woong; Bae, Joon-Yong; Park, Mee Sook; Park, Hyoung Jin; Park, Man-Seong

    2013-10-01

    Herbal medicine has been used in the orient for thousands of years to treat large and small ailments, including microbial infections. Although there are treatments for influenza virus infection, there is no treatment for drug-resistant viruses. It is time that we explored and exploited the multi-component nature of herbal extracts as multi-drug combination therapies. Here, we present data on the anti-influenza virus effect of a medicinal mushroom, Phellinus igniarius. The P. igniarius water extract was effective against influenza A and B viruses, including 2009 pandemic H1N1, human H3N2, avian H9N2, and oseltamivir-resistant H1N1 viruses. Virological assays revealed that the extract may interfere with one or more early events in the influenza virus replication cycle, including viral attachment to the target cell. Therefore, our results provide new insights into the use of P. igniarius as an anti-influenza medicine. PMID:24173646

  9. Incoming Influenza A Virus Evades Early Host Recognition, while Influenza B Virus Induces Interferon Expression Directly upon Entry

    PubMed Central

    Strengell, Mari; Sarin, L. Peter; Poranen, Minna M.; Fagerlund, Riku; Melén, Krister; Julkunen, Ilkka

    2012-01-01

    The activation of the interferon (IFN) system, which is triggered largely by the recognition of viral nucleic acids, is one of the most important host defense reactions against viral infections. Although influenza A and B viruses, which both have segmented negative-strand RNA genomes, share major structural similarities, they have evolutionarily diverged, with total genetic incompatibility. Here we compare antiviral-inducing mechanisms during infections with type A and B influenza viruses in human dendritic cells. We observed that IFN responses are induced significantly faster in cells infected with influenza B virus than in cells infected with type A influenza virus and that the early induction of antiviral gene expression is mediated by the activation of the transcription factor IFN regulatory factor 3 (IRF3). We further demonstrate that influenza A virus infection activates IFN responses only after viral RNA (vRNA) synthesis, whereas influenza B virus induces IFN responses even if its infectivity is destroyed by UV treatment. Thus, initial viral transcription, replication, and viral protein synthesis are dispensable for influenza B virus-induced antiviral responses. Moreover, vRNA molecules from both type A and B viruses are equally potent activators of IFN induction, but incoming influenza B virus structures are recognized directly in the cytosol, while influenza A virus is able to evade early recognition. Collectively, our data provide new evidence of a novel antiviral evasion strategy for influenza A virus without a contribution of the viral NS1 protein, and this opens up new insights into different influenza virus pathogenicities. PMID:22855501

  10. Incoming influenza A virus evades early host recognition, while influenza B virus induces interferon expression directly upon entry.

    PubMed

    Österlund, Pamela; Strengell, Mari; Sarin, L Peter; Poranen, Minna M; Fagerlund, Riku; Melén, Krister; Julkunen, Ilkka

    2012-10-01

    The activation of the interferon (IFN) system, which is triggered largely by the recognition of viral nucleic acids, is one of the most important host defense reactions against viral infections. Although influenza A and B viruses, which both have segmented negative-strand RNA genomes, share major structural similarities, they have evolutionarily diverged, with total genetic incompatibility. Here we compare antiviral-inducing mechanisms during infections with type A and B influenza viruses in human dendritic cells. We observed that IFN responses are induced significantly faster in cells infected with influenza B virus than in cells infected with type A influenza virus and that the early induction of antiviral gene expression is mediated by the activation of the transcription factor IFN regulatory factor 3 (IRF3). We further demonstrate that influenza A virus infection activates IFN responses only after viral RNA (vRNA) synthesis, whereas influenza B virus induces IFN responses even if its infectivity is destroyed by UV treatment. Thus, initial viral transcription, replication, and viral protein synthesis are dispensable for influenza B virus-induced antiviral responses. Moreover, vRNA molecules from both type A and B viruses are equally potent activators of IFN induction, but incoming influenza B virus structures are recognized directly in the cytosol, while influenza A virus is able to evade early recognition. Collectively, our data provide new evidence of a novel antiviral evasion strategy for influenza A virus without a contribution of the viral NS1 protein, and this opens up new insights into different influenza virus pathogenicities.

  11. H7N9 influenza A virus in turkeys in Minnesota.

    PubMed

    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; Brown, Justin D

    2015-02-01

    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.

  12. 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

  13. Inhibition of influenza virus replication by plant-derived isoquercetin.

    PubMed

    Kim, Yunjeong; Narayanan, Sanjeev; Chang, Kyeong-Ok

    2010-11-01

    Influenza virus infects the respiratory system of human and animals causing mild to severe illness which could lead to death. Although vaccines are available, there is still a great need for influenza antiviral drugs to reduce disease progression and virus transmission. Currently two classes (M2 channel blockers and neuraminidase inhibitors) of FDA-approved influenza antiviral drugs are available, but there are great concerns of emergence of viral resistance. Therefore, timely development of new antiviral drugs against influenza viruses is crucial. Plant-derived polyphenols have been studied for antioxidant activity, anti-carcinogenic, and cardio- and neuroprotective actions. Recently, some polyphenols, such as resveratrol and epigallocatechin gallate, showed significant anti-influenza activity in vitro and/or in vivo. Therefore we investigated selected polyphenols for their antiviral activity against influenza A and B viruses. Among the polyphenols we tested, isoquercetin inhibited the replication of both influenza A and B viruses at the lowest effective concentration. In a double treatment of isoquercetin and amantadine, synergistic effects were observed on the reduction of viral replication in vitro. The serial passages of virus in the presence of isoquercetin did not lead to the emergence of resistant virus, and the addition of isoquercetin to amantadine or oseltamivir treatment suppressed the emergence of amantadine- or oseltamivir-resistant virus. In a mouse model of influenza virus infection, isoquercetin administered intraperitoneally to mice inoculated with human influenza A virus significantly decreased the virus titers and pathological changes in the lung. Our results suggest that isoquercetin may have the potential to be developed as a therapeutic agent for the treatment of influenza virus infection and for the suppression of resistance in combination therapy with existing drugs.

  14. 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

  15. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Freshwater clams as bioconcentrators of avian influenza virus in water.

    PubMed

    Huyvaert, Kathryn P; Carlson, Jenny S; Bentler, Kevin T; Cobble, Kacy R; Nolte, Dale L; Franklin, Alan B

    2012-10-01

    We report experimental evidence for bioconcentration of a low-pathogenicity avian influenza virus (H6N8) in the tissue of freshwater clams. Our results support the concept that freshwater clams may provide an effective tool for use in the early detection of influenza A viruses in aquatic environments. PMID:22925022

  18. 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.

  19. 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

  20. 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...

  1. 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...

  2. 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),...

  3. 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

  4. 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

  5. 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

    2015-01-16

    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.

  6. Influenza virus induces apoptosis via BAD-mediated mitochondrial dysregulation.

    PubMed

    Tran, Anh T; Cortens, John P; Du, Qiujiang; Wilkins, John A; Coombs, Kevin M

    2013-01-01

    Influenza virus infection results in host cell death and major tissue damage. Specific components of the apoptotic pathway, a signaling cascade that ultimately leads to cell death, are implicated in promoting influenza virus replication. BAD is a cell death regulator that constitutes a critical control point in the intrinsic apoptosis pathway, which occurs through the dysregulation of mitochondrial outer membrane permeabilization and the subsequent activation of downstream apoptogenic factors. Here we report a novel proviral role for the proapoptotic protein BAD in influenza virus replication. We show that influenza virus-induced cytopathology and cell death are considerably inhibited in BAD knockdown cells and that both virus replication and viral protein production are dramatically reduced, which suggests that virus-induced apoptosis is BAD dependent. Our data showed that influenza viruses induced phosphorylation of BAD at residues S112 and S136 in a temporal manner. Viral infection also induced BAD cleavage, late in the viral life cycle, to a truncated form that is reportedly a more potent inducer of apoptosis. We further demonstrate that knockdown of BAD resulted in reduced cytochrome c release and suppression of the intrinsic apoptotic pathway during influenza virus replication, as seen by an inhibition of caspases-3, caspase-7, and procyclic acidic repetitive protein (PARP) cleavage. Our data indicate that influenza viruses carefully modulate the activation of the apoptotic pathway that is dependent on the regulatory function of BAD and that failure of apoptosis activation resulted in unproductive viral replication.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. Influenza A and B Virus Intertypic Reassortment through Compatible Viral Packaging Signals

    PubMed Central

    Baker, Steven F.; Nogales, Aitor; Finch, Courtney; Tuffy, Kevin M.; Domm, William; Perez, Daniel R.; Topham, David J.

    2014-01-01

    ABSTRACT Influenza A and B viruses cocirculate in humans and together cause disease and seasonal epidemics. These two types of influenza viruses are evolutionarily divergent, and exchange of genetic segments inside coinfected cells occurs frequently within types but never between influenza A and B viruses. Possible mechanisms inhibiting the intertypic reassortment of genetic segments could be due to incompatible protein functions of segment homologs, a lack of processing of heterotypic segments by influenza virus RNA-dependent RNA polymerase, an inhibitory effect of viral proteins on heterotypic virus function, or an inability to specifically incorporate heterotypic segments into budding virions. Here, we demonstrate that the full-length hemagglutinin (HA) of prototype influenza B viruses can complement the function of multiple influenza A viruses. We show that viral noncoding regions were sufficient to drive gene expression for either type A or B influenza virus with its cognate or heterotypic polymerase. The native influenza B virus HA segment could not be incorporated into influenza A virus virions. However, by adding the influenza A virus packaging signals to full-length influenza B virus glycoproteins, we rescued influenza A viruses that possessed HA, NA, or both HA and NA of influenza B virus. Furthermore, we show that, similar to single-cycle infectious influenza A virus, influenza B virus cannot incorporate heterotypic transgenes due to packaging signal incompatibilities. Altogether, these results demonstrate that the lack of influenza A and B virus reassortants can be attributed at least in part to incompatibilities in the virus-specific packaging signals required for effective segment incorporation into nascent virions. IMPORTANCE Reassortment of influenza A or B viruses provides an evolutionary strategy leading to unique genotypes, which can spawn influenza A viruses with pandemic potential. However, the mechanism preventing intertypic reassortment or

  12. 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

  13. Molecular Basis of Live-Attenuated Influenza Virus

    PubMed Central

    He, Wen; Wang, Wei; Han, Huamin; Wang, Lei; Zhang, Ge; Gao, Bin

    2013-01-01

    Human influenza is a seasonal disease associated with significant morbidity and mortality. The most effective means for controlling infection and thereby reducing morbidity and mortality is vaccination with a three inactivated influenza virus strains mixture, or by intranasal administration of a group of three different live attenuated influenza vaccine strains. Comparing to the inactivated vaccine, the attenuated live viruses allow better elicitation of a long-lasting and broader immune (humoral and cellular) response that represents a naturally occurring transient infection. The cold-adapted (ca) influenza A/AA/6/60 (H2N2) (AA ca) virus is the backbone for the live attenuated trivalent seasonal influenza vaccine licensed in the United States. Similarly, the influenza A components of live-attenuated vaccines used in Russia have been prepared as reassortants of the cold-adapted (ca) H2N2 viruses, A/Leningrad/134/17/57-ca (Len/17) and A/Leningrad/134/47/57-ca (Len/47) along with virulent epidemic strains. However, the mechanism of temperature-sensitive attenuation is largely elusive. To understand how modification at genetic level of influenza virus would result in attenuation of human influenza virus A/PR/8/34 (H1N1,A/PR8), we investigated the involvement of key mutations in the PB1 and/or PB2 genes in attenuation of influenza virus in vitro and in vivo. We have demonstrated that a few of residues in PB1 and PB2 are critical for the phenotypes of live attenuated, temperature sensitive influenza viruses by minigenome assay and real-time PCR. The information of these mutation loci could be used for elucidation of mechanism of temperature-sensitive attenuation and as a new strategy for influenza vaccine development. PMID:23555969

  14. 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

  15. 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

  16. Inhibition of influenza virus internalization by (-)-epigallocatechin-3-gallate.

    PubMed

    Kim, Meehyein; Kim, So-Yeon; Lee, Hye Won; Shin, Jin Soo; Kim, Pilho; Jung, Young-Sik; Jeong, Hyeong-Seop; Hyun, Jae-Kyung; Lee, Chong-Kyo

    2013-11-01

    (-)-Epigallocatechin-3-gallate (EGCG), one of the major flavonoid components of green tea, is known to have a broad antiviral activity against several enveloped viruses, including the influenza virus. However, its mode of action and the mechanism that allows it to target influenza virus molecules have not been fully elucidated. Thus, this study investigated the molecular mechanism by which EGCG suppresses influenza virus infections. EGCG was found to block an early step in the influenza viral life cycle, but it did not affect viral adsorption to target cells or viral RNA replication. However, EGCG inhibited hemifusion events between virus particles and the cellular membrane by reducing the viral membrane integrity, thereby resulting in the loss of the cell penetration capacity of the influenza virus. EGCG also marginally suppressed the viral and nonviral neuraminidase (NA) activity in an enzyme-based assay system. In conclusion, it is suggested that the anti-influenza viral efficacy of EGCG is attributable to damage to the physical properties of the viral envelope and partial inhibition of the NA surface glycoprotein. These results may facilitate future investigations of the antiviral activity of EGCG against other enveloped viruses as well as influenza virus. PMID:23954192

  17. 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.

  18. 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

  19. Influenza vaccines: from whole virus preparations to recombinant protein technology.

    PubMed

    Huber, Victor C

    2014-01-01

    Vaccination against influenza represents our most effective form of prevention. Historical approaches toward vaccine creation and production have yielded highly effective vaccines that are safe and immunogenic. Despite their effectiveness, these historical approaches do not allow for the incorporation of changes into the vaccine in a timely manner. In 2013, a recombinant protein-based vaccine that induces immunity toward the influenza virus hemagglutinin was approved for use in the USA. This vaccine represents the first approved vaccine formulation that does not require an influenza virus intermediate for production. This review presents a brief history of influenza vaccines, with insight into the potential future application of vaccines generated using recombinant technology.

  20. A Closer Look at the NS1 of Influenza Virus

    PubMed Central

    Dundon, William G.; Capua, Ilaria

    2009-01-01

    The Non-Structural 1 (NS1) protein is a multifactorial protein of type A influenza viruses that plays an important role in the virulence of the virus. A large amount of what we know about this protein has been obtained from studies using human influenza isolates and, consequently, the human NS1 protein. The current global interest in avian influenza, however, has highlighted a number of sequence and functional differences between the human and avian NS1. This review discusses these differences in addition to describing potential uses of NS1 in the management and control of avian influenza outbreaks. PMID:21994582

  1. 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.

  2. 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

  3. Influenza virus sequence feature variant type analysis: evidence of a role for NS1 in influenza virus host range restriction.

    PubMed

    Noronha, Jyothi M; Liu, Mengya; Squires, R Burke; Pickett, Brett E; Hale, Benjamin G; Air, Gillian M; Galloway, Summer E; Takimoto, Toru; Schmolke, Mirco; Hunt, Victoria; Klem, Edward; García-Sastre, Adolfo; McGee, Monnie; Scheuermann, Richard H

    2012-05-01

    Genetic drift of influenza virus genomic sequences occurs through the combined effects of sequence alterations introduced by a low-fidelity polymerase and the varying selective pressures experienced as the virus migrates through different host environments. While traditional phylogenetic analysis is useful in tracking the evolutionary heritage of these viruses, the specific genetic determinants that dictate important phenotypic characteristics are often difficult to discern within the complex genetic background arising through evolution. Here we describe a novel influenza virus sequence feature variant type (Flu-SFVT) approach, made available through the public Influenza Research Database resource (www.fludb.org), in which variant types (VTs) identified in defined influenza virus protein sequence features (SFs) are used for genotype-phenotype association studies. Since SFs have been defined for all influenza virus proteins based on known structural, functional, and immune epitope recognition properties, the Flu-SFVT approach allows the rapid identification of the molecular genetic determinants of important influenza virus characteristics and their connection to underlying biological functions. We demonstrate the use of the SFVT approach to obtain statistical evidence for effects of NS1 protein sequence variations in dictating influenza virus host range restriction.

  4. In vitro evaluation of the antiviral activity of methylglyoxal against influenza B virus infection.

    PubMed

    Charyasriwong, Siriwan; Haruyama, Takahiro; Kobayashi, Nobuyuki

    2016-01-01

    Influenza A and B virus infections are serious public health concerns globally. However, the concerns regarding influenza B infection have been underestimated. The currently used anti-influenza drugs have not provided equal efficacy for both influenza A and B viruses. Susceptibility to neuraminidase (NA) inhibitors has been observed to be lower for influenza B viruses than for influenza A viruses. Moreover, the emergence of resistance to anti-influenza drugs underscores the need to develop new drugs. Recently, we reported that methylglyoxal (MGO) suppressed influenza A virus replication in a strain-independent manner. Therefore, we hypothesize that MGO exhibits anti-influenza activity against B strains. This study aimed to evaluate the anti-influenza viral activity of MGO against influenza B strains by using Madin-Darby canine kidney (MDCK) cells. Several types of influenza B viruses were used to determine the activity of MGO. The susceptibilities of influenza A and B viruses to NA inhibitors were compared. MGO inhibited influenza B virus replication, with 50% inhibitory concentrations ranging from 23-140 μM, which indicated greater sensitivity of influenza B viruses than influenza A viruses. Our results show that MGO has potent inhibitory activity against influenza B viruses, including NA inhibitor-resistant strains. PMID:27558282

  5. 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

  6. 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.

  7. Comparative mutational analyses of influenza A viruses

    PubMed Central

    Cheung, Peter Pak-Hang; Rogozin, Igor B.; Choy, Ka-Tim; Ng, Hoi Yee

    2015-01-01

    The error-prone RNA-dependent RNA polymerase (RdRP) and external selective pressures are the driving forces for RNA viral diversity. When confounded by selective pressures, it is difficult to assess if influenza A viruses (IAV) that have a wide host range possess comparable or distinct spontaneous mutational frequency in their RdRPs. We used in-depth bioinformatics analyses to assess the spontaneous mutational frequencies of two RdRPs derived from human seasonal (A/Wuhan/359/95; Wuhan) and H5N1 (A/Vietnam/1203/04; VN1203) viruses using the mini-genome system with a common firefly luciferase reporter serving as the template. High-fidelity reverse transcriptase was applied to generate high-quality mutational spectra which allowed us to assess and compare the mutational frequencies and mutable motifs along a target sequence of the two RdRPs of two different subtypes. We observed correlated mutational spectra (τ correlation P < 0.0001), comparable mutational frequencies (H3N2:5.8 ± 0.9; H5N1:6.0 ± 0.5), and discovered a highly mutable motif “(A)AAG” for both Wuhan and VN1203 RdRPs. Results were then confirmed with two recombinant A/Puerto Rico/8/34 (PR8) viruses that possess RdRP derived from Wuhan or VN1203 (RG-PR8×WuhanPB2, PB1, PA, NP and RG-PR8×VN1203PB2, PB1, PA, NP). Applying novel bioinformatics analysis on influenza mutational spectra, we provide a platform for a comprehensive analysis of the spontaneous mutation spectra for an RNA virus. PMID:25404565

  8. 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.

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

    PubMed Central

    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

  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. Imaging of influenza virus sialidase activity in living cells.

    PubMed

    Kurebayashi, Yuuki; Takahashi, Tadanobu; Otsubo, Tadamune; Ikeda, Kiyoshi; Takahashi, Shunsaku; Takano, Maiko; Agarikuchi, Takashi; Sato, Tsubasa; Matsuda, Yukino; Minami, Akira; Kanazawa, Hiroaki; Uchida, Yuko; Saito, Takehiko; Kawaoka, Yoshihiro; Yamada, Toshihiro; Kawamori, Fumihiko; Thomson, Robin; von Itzstein, Mark; Suzuki, Takashi

    2014-01-01

    Influenza virus is rich in variation and mutations. It would be very convenient for virus detection and isolation to histochemically detect viral infection regardless of variation and mutations. Here, we established a histochemical imaging assay for influenza virus sialidase activity in living cells by using a new fluorescent sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac). The BTP3-Neu5Ac assay histochemically visualized influenza virus-infected cells regardless of viral hosts and subtypes. Influenza virus neuraminidase-expressed cells, viral focus formation, and virus-infected locations in mice lung tissues were easily, rapidly, and sensitively detected by the BTP3-Neu5Ac assay. Histochemical visualization with the BTP3-Neu5Ac assay is extremely useful for detection of influenza viruses without the need for fixation or a specific antibody. This novel assay should greatly improve the efficiency of detection, titration, and isolation of influenza viruses and might contribute to research on viral sialidase.

  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. Evolution of Influenza B Virus in Kuala Lumpur, Malaysia, between 1995 and 2008.

    PubMed

    Sam, I-Ching; Su, Yvonne C F; Chan, Yoke Fun; Nor'E, Siti Sarah; Hassan, Ardalinah; Jafar, Faizatul Lela; Joseph, Udayan; Halpin, Rebecca A; Ghedin, Elodie; Hooi, Poh Sim; Fourment, Mathieu; Hassan, Hamimah; AbuBakar, Sazaly; Wentworth, David E; Smith, Gavin J D

    2015-09-01

    Influenza B virus causes significant disease but remains understudied in tropical regions. We sequenced 72 influenza B viruses collected in Kuala Lumpur, Malaysia, from 1995 to 2008. The predominant circulating lineage (Victoria or Yamagata) changed every 1 to 3 years, and these shifts were associated with increased incidence of influenza B. We also found poor lineage matches with recommended influenza virus vaccine strains. While most influenza B virus lineages in Malaysia were short-lived, one circulated for 3 to 4 years.

  14. Pandemic potential of H7N9 influenza viruses

    PubMed Central

    Watanabe, Tokiko; Watanabe, Shinji; Maher, Eileen A.; Neumann, Gabriele; Kawaoka, Yoshihiro

    2014-01-01

    Avian influenza viruses rarely infect humans, but the recently emerged avian H7N9 influenza viruses have caused sporadic infections in humans in China, resulting in 440 confirmed cases with 122 fatalities as of May 16, 2014. In addition, epidemiologic surveys suggest that there have been asymptomatic or mild human infections with H7N9 viruses. These viruses replicate efficiently in mammals, show limited transmissibility in ferrets and guinea pigs, and possess mammalian-adapting amino acid changes that likely contribute to their ability to infect mammals. Here, we summarize the characteristic features of the novel H7N9 viruses and assess their pandemic potential. PMID:25264312

  15. Rapidly Expanding Range of Highly Pathogenic Avian Influenza Viruses.

    PubMed

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

    2015-07-01

    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.

  16. SnapShot: Evolution of human influenza A viruses.

    PubMed

    Wendel, Isabel; Matrosovich, Mikhail; Klenk, Hans Dieter

    2015-03-11

    The major natural hosts of influenza A viruses are wild aquatic birds. Occasionally, viruses are transmitted to mammalian and other avian species, including humans. Due to the high mutation rate and reassortment of the viral genome, the viruses may undergo adaptation to humans and then give rise to a pandemic.

  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. 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...

  19. Emergence of amantadine-resistant influenza A viruses: epidemiological study.

    PubMed

    Suzuki, Hiroshi; Saito, Reiko; Masuda, Hiroki; Oshitani, Hitoshi; Sato, Mizuho; Sato, Isamu

    2003-09-01

    At present, three licensed antiviral influenza agents are available in Japan: amantadine, zanamivir, and oseltamivir. These antiviral agents can be used for controlling and preventing influenza, but they are not a substitute for vaccination. Amantadine is an antiviral drug with activity against influenza A viruses, but not influenza B viruses. Persons who have influenza A infection and who are treated with amantadine can shed sensitive viruses early in the course of treatment and later shed drug-resistant viruses, especially after 5-7 days of therapy. Such persons can benefit from therapy even when resistant viruses emerge. In screening for amantadine susceptibility, enzyme-linked immunoassays, plaque reduction assays, and TCID50/0.2 ml titration are employed. The molecular changes associated with resistance have been identified as single-nucleotide changes, leading to corresponding amino acid substitutions in one of four critical sites, amino acids 26, 27, 30, and 31, in the transmembrane region of the M2 protein. The polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis method is quite useful. Resistant viruses have been circulated in outbreak situations at nursing homes where amantadine was used not only for treating influenza virus infection but also for Parkinson's disease. Measures should be taken to reduce contact, as much as possible, between persons taking and those not taking antiviral drugs for treatment or chemoprophylaxis.

  20. [Studies on sialidase and esterase in influenza viruses].

    PubMed

    Cabezas, J A

    1991-01-01

    The main contributions of the author and collaborators about sialidase (EC 3.2.1.18) of influenza virus types A and B and O-acetylesterase (EC 3.1.1.53) of type C are summarized. After a short introduction on the topic, the negative results obtained by the author on inhibitors are commented. Then, the peculiarities of the three procedures assayed, based on the NADH determination as a measurement for the sialidase activity, are discussed. The spectrofluorimetric measurement of NADH concentration is a more sensitive and convenient procedure than that by spectrophotometry, although it is less sensitive than that based on bioluminiscence. Sialidase activity is generally higher in influenza virus type A than in type B; however, some differences have been found between the three sub-types A analysed. Furthermore, thermal stability and stability against changes in the pH values are higher for influenza virus from ducks, followed by those from humans and, finally, by those from pigs. O-acetylesterase of influenza virus type C shows a broad specificity; it acts on O-acetyl-containing compounds which may not be sialic acids. It seems that this enzyme might contribute to facilitate the action of sialidase of influenza virus types A and B. The peculiarities of influenza virus type C suggest to include this type as a new genus in the future classification of viruses.

  1. 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

  2. Influenza virus and endothelial cells: a species specific relationship

    PubMed Central

    Short, Kirsty R.; Veldhuis Kroeze, Edwin J. B.; Reperant, Leslie A.; Richard, Mathilde; Kuiken, Thijs

    2014-01-01

    Influenza A virus (IAV) infection is an important cause of respiratory disease in humans. The original reservoirs of IAV are wild waterfowl and shorebirds, where virus infection causes limited, if any, disease. Both in humans and in wild waterbirds, epithelial cells are the main target of infection. However, influenza virus can spread from wild bird species to terrestrial poultry. Here, the virus can evolve into highly pathogenic avian influenza (HPAI). Part of this evolution involves increased viral tropism for endothelial cells. HPAI virus infections not only cause severe disease in chickens and other terrestrial poultry species but can also spread to humans and back to wild bird populations. Here, we review the role of the endothelium in the pathogenesis of influenza virus infection in wild birds, terrestrial poultry and humans with a particular focus on HPAI viruses. We demonstrate that whilst the endothelium is an important target of virus infection in terrestrial poultry and some wild bird species, in humans the endothelium is more important in controlling the local inflammatory milieu. Thus, the endothelium plays an important, but species-specific, role in the pathogenesis of influenza virus infection. PMID:25520707

  3. Active surveillance for avian influenza virus, Egypt, 2010-2012.

    PubMed

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

    2014-04-01

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

  4. Modes of Transmission of Influenza B Virus in Households

    PubMed Central

    Cowling, Benjamin J.; Ip, Dennis K. M.; Fang, Vicky J.; Suntarattiwong, Piyarat; Olsen, Sonja J.; Levy, Jens; Uyeki, Timothy M.; Leung, Gabriel M.; Peiris, J. S. Malik; Chotpitayasunondh, Tawee; Nishiura, Hiroshi; Simmerman, J. Mark

    2014-01-01

    Introduction While influenza A and B viruses can be transmitted via respiratory droplets, the importance of small droplet nuclei “aerosols” in transmission is controversial. Methods and Findings In Hong Kong and Bangkok, in 2008–11, subjects were recruited from outpatient clinics if they had recent onset of acute respiratory illness and none of their household contacts were ill. Following a positive rapid influenza diagnostic test result, subjects were randomly allocated to one of three household-based interventions: hand hygiene, hand hygiene plus face masks, and a control group. Index cases plus their household contacts were followed for 7–10 days to identify secondary infections by reverse transcription polymerase chain reaction (RT-PCR) testing of respiratory specimens. Index cases with RT-PCR-confirmed influenza B were included in the present analyses. We used a mathematical model to make inferences on the modes of transmission, facilitated by apparent differences in clinical presentation of secondary infections resulting from aerosol transmission. We estimated that approximately 37% and 26% of influenza B virus transmission was via the aerosol mode in households in Hong Kong and Bangkok, respectively. In the fitted model, influenza B virus infections were associated with a 56%–72% risk of fever plus cough if infected via aerosol route, and a 23%–31% risk of fever plus cough if infected via the other two modes of transmission. Conclusions Aerosol transmission may be an important mode of spread of influenza B virus. The point estimates of aerosol transmission were slightly lower for influenza B virus compared to previously published estimates for influenza A virus in both Hong Kong and Bangkok. Caution should be taken in interpreting these findings because of the multiple assumptions inherent in the model, including that there is limited biological evidence to date supporting a difference in the clinical features of influenza B virus infection by

  5. 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

  6. Influenza A virus--induced acute otitis media.

    PubMed

    Buchman, C A; Doyle, W J; Skoner, D P; Post, J C; Alper, C M; Seroky, J T; Anderson, K; Preston, R A; Hayden, F G; Fireman, P

    1995-11-01

    To better understand the significance of viral upper respiratory tract infections in the pathogenesis of acute otitis media (OM), 27 adults underwent intranasal inoculation with influenza A virus. Monitoring consisted of antibody titer determination, tympanometry, and otoscopy. Microbiologic analysis consisted of cultures and polymerase chain reaction (PCR)-based detection for influenza A virus, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. All subjects became infected with the challenge virus. By day 4, 16 (59%) developed middle ear pressures of -100 mm H2O or below and 4 (25%) of them developed OM. One subject (4%) developed purulent OM requiring myringotomy for pain relief. Middle ear effusion cultures were negative. PCR analysis of that subject's middle ear effusion and nasal washes were positive for influenza A virus and S. pneumoniae. These findings support a causal role for viral upper respiratory tract infections in the pathogenesis of OM, possibly mediated by middle ear underpressures and viral and bacterial middle ear infection.

  7. 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

  8. Inhibition of influenza A virus replication by rifampicin and selenocystamine

    SciTech Connect

    Hamzehei, M.; Ledinko, N.

    1980-01-01

    The effects of selenocystamine, an inhibitor of influenza virus RNA-dependent RNA polymerase in vitro activity, in the antibiotic rifampicin were studied on influenza A/PR/8/34 (HON1) infection in embryonated eggs. Both drugs completely inhibited hemagglutinating and infective virus yields when added at relatively early times postinfection. Maximal inhibition was produced by apparently noncytotoxic concentrations of 50 microgram of selenocystamine, or of 400 microgram of rifampicin, per egg.

  9. Sequential Seasonal H1N1 Influenza Virus Infections Protect Ferrets against Novel 2009 H1N1 Influenza Virus

    PubMed Central

    Carter, Donald M.; Bloom, Chalise E.; Nascimento, Eduardo J. M.; Marques, Ernesto T. A.; Craigo, Jodi K.; Cherry, Joshua L.; Lipman, David J.

    2013-01-01

    Individuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses. PMID:23115287

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

    PubMed

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

    2011-04-01

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

  11. Detection of Nonhemagglutinating Influenza A(H3) Viruses by Enzyme-Linked Immunosorbent Assay in Quantitative Influenza Virus Culture

    PubMed Central

    Els, C.; Sprong, L.; van Beek, R.; van der Vries, E.; Osterhaus, A. D. M. E.; Rimmelzwaan, G. F.

    2014-01-01

    To assess the efficacy of novel antiviral drugs against influenza virus in clinical trials, it is necessary to quantify infectious virus titers in respiratory tract samples from patients. Typically, this is achieved by inoculating virus-susceptible cells with serial dilutions of clinical specimens and detecting the production of progeny virus by hemagglutination, since influenza viruses generally have the capacity to bind and agglutinate erythrocytes of various species through their hemagglutinin (HA). This readout method is no longer adequate, since an increasing number of currently circulating influenza A virus H3 subtype (A[H3]) viruses display a reduced capacity to agglutinate erythrocytes. Here, we report the magnitude of this problem by analyzing the frequency of HA-deficient A(H3) viruses detected in The Netherlands from 1999 to 2012. Furthermore, we report the development and validation of an alternative method for monitoring the production of progeny influenza virus in quantitative virus cultures, which is independent of the capacity to agglutinate erythrocytes. This method is based on the detection of viral nucleoprotein (NP) in virus culture plates by enzyme-linked immunosorbent assay (ELISA), and it produced results similar to those of the hemagglutination assay using strains with good HA activity, including A/Brisbane/059/07 (H1N1), A/Victoria/210/09 (H3N2), other seasonal A(H1N1), A(H1N1)pdm09, and the majority of A(H3) virus strains isolated in 2009. In contrast, many A(H3) viruses that have circulated since 2010 failed to display HA activity, and infectious virus titers were determined only by detecting NP. The virus culture ELISA described here will enable efficacy testing of new antiviral compounds in clinical trials during seasons in which nonhemagglutinating influenza A viruses circulate. PMID:24622097

  12. Detection of nonhemagglutinating influenza a(h3) viruses by enzyme-linked immunosorbent assay in quantitative influenza virus culture.

    PubMed

    van Baalen, C A; Els, C; Sprong, L; van Beek, R; van der Vries, E; Osterhaus, A D M E; Rimmelzwaan, G F

    2014-05-01

    To assess the efficacy of novel antiviral drugs against influenza virus in clinical trials, it is necessary to quantify infectious virus titers in respiratory tract samples from patients. Typically, this is achieved by inoculating virus-susceptible cells with serial dilutions of clinical specimens and detecting the production of progeny virus by hemagglutination, since influenza viruses generally have the capacity to bind and agglutinate erythrocytes of various species through their hemagglutinin (HA). This readout method is no longer adequate, since an increasing number of currently circulating influenza A virus H3 subtype (A[H3]) viruses display a reduced capacity to agglutinate erythrocytes. Here, we report the magnitude of this problem by analyzing the frequency of HA-deficient A(H3) viruses detected in The Netherlands from 1999 to 2012. Furthermore, we report the development and validation of an alternative method for monitoring the production of progeny influenza virus in quantitative virus cultures, which is independent of the capacity to agglutinate erythrocytes. This method is based on the detection of viral nucleoprotein (NP) in virus culture plates by enzyme-linked immunosorbent assay (ELISA), and it produced results similar to those of the hemagglutination assay using strains with good HA activity, including A/Brisbane/059/07 (H1N1), A/Victoria/210/09 (H3N2), other seasonal A(H1N1), A(H1N1)pdm09, and the majority of A(H3) virus strains isolated in 2009. In contrast, many A(H3) viruses that have circulated since 2010 failed to display HA activity, and infectious virus titers were determined only by detecting NP. The virus culture ELISA described here will enable efficacy testing of new antiviral compounds in clinical trials during seasons in which nonhemagglutinating influenza A viruses circulate.

  13. 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

  14. Global transmission of influenza viruses from humans to swine

    PubMed Central

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

    2012-01-01

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

  15. An Ultrasensitive Mechanism Regulates Influenza Virus-Induced Inflammation

    PubMed Central

    Shoemaker, Jason E.; Fukuyama, Satoshi; Eisfeld, Amie J.; Zhao, Dongming; Kawakami, Eiryo; Sakabe, Saori; Maemura, Tadashi; Gorai, Takeo; Katsura, Hiroaki; Muramoto, Yukiko; Watanabe, Shinji; Watanabe, Tokiko; Fuji, Ken; Matsuoka, Yukiko; Kitano, Hiroaki; Kawaoka, Yoshihiro

    2015-01-01

    Influenza viruses present major challenges to public health, evident by the 2009 influenza pandemic. Highly pathogenic influenza virus infections generally coincide with early, high levels of inflammatory cytokines that some studies have suggested may be regulated in a strain-dependent manner. However, a comprehensive characterization of the complex dynamics of the inflammatory response induced by virulent influenza strains is lacking. Here, we applied gene co-expression and nonlinear regression analysis to time-course, microarray data developed from influenza-infected mouse lung to create mathematical models of the host inflammatory response. We found that the dynamics of inflammation-associated gene expression are regulated by an ultrasensitive-like mechanism in which low levels of virus induce minimal gene expression but expression is strongly induced once a threshold virus titer is exceeded. Cytokine assays confirmed that the production of several key inflammatory cytokines, such as interleukin 6 and monocyte chemotactic protein 1, exhibit ultrasensitive behavior. A systematic exploration of the pathways regulating the inflammatory-associated gene response suggests that the molecular origins of this ultrasensitive response mechanism lie within the branch of the Toll-like receptor pathway that regulates STAT1 phosphorylation. This study provides the first evidence of an ultrasensitive mechanism regulating influenza virus-induced inflammation in whole lungs and provides insight into how different virus strains can induce distinct temporal inflammation response profiles. The approach developed here should facilitate the construction of gene regulatory models of other infectious diseases. PMID:26046528

  16. 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

  17. Prevention of acute otitis media by prophylaxis and treatment of influenza virus infections.

    PubMed

    Glezen, W P

    2000-12-01

    Human experimental challenge studies with influenza virus infection and controlled intervention trials have demonstrated beyond doubt the role of influenza virus infection in the pathogenesis of acute otitis media. Influenza virus infections not only disrupt eustachian tube function, but also impair recovery from infection and facilitate attachment of bacterial pathogens to respiratory epithelial cells. Immunization of young children with either inactivated or live, attenuated influenza vaccine will significantly reduce the incidence of acute otitis media. Early treatment of influenza with antiviral medication will reduce eustachian tube dysfunction that results from influenza virus infection. Influenza produces high morbidity in children that could be averted by universal immunization with attenuated nasal spray vaccine.

  18. Inhibition of Influenza Virus Ribonucleic Acid Polymerase by Ribavirin Triphosphate

    PubMed Central

    Eriksson, Bertil; Helgstrand, Erik; Johansson, Nils Gunnar; Larsson, Alf; Misiorny, Alfons; Noren, Jan Olof; Philipson, Lennart; Stenberg, Kjell; Stening, Goran; Stridh, Stig; Öberg, Bo

    1977-01-01

    Ribavirin 5′-triphosphate (RTP), derived from the broad-spectrum antiviral compound ribavirin (Virazole), can selectively inhibit influenza virus ribonucleic acid polymerase in a cell-free assay. Ribavirin and its 5′-monophosphate have no effect on the polymerase. The inhibition is competitive with respect to adenosine 5′-triphosphate and guanosine 5′-triphosphate. RTP also inhibits ApG- and GpC-stimulated influenza virus ribonucleic acid polymerase. Since ribavirin is phosphorylated in the cell, the inhibition of influenza multiplication in the cell may also be caused by RTP. PMID:879760

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

    PubMed

    Barba, Marta; Daly, Janet M

    2016-08-31

    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.

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

    PubMed Central

    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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. Dissecting the Role of COPI Complexes in Influenza Virus Infection

    PubMed Central

    Sun, Eileen; He, Jiang

    2013-01-01

    As an obligate pathogen, influenza virus requires host cell factors and compartments to mediate productive infection and to produce infectious progeny virus. Recently, several small interfering RNA (siRNA) knockdown screens revealed influenza virus host dependency proteins, all of which identified at least two subunits of the coat protein I (COPI) complex. COPI proteins oligomerize to form coated vesicles that transport contents between the Golgi apparatus and the endoplasmic reticulum, and they have also been reported to mediate endosomal trafficking. However, it remains unclear which steps in the influenza virus infection cycle rely on the COPI complex. Upon systematic dissection of the influenza virus infection cycle, from entry to progeny virion production, we found that prolonged exposure to COPI complex disruption through siRNA depletion resulted in significant defects in virus internalization and trafficking to late endosomes. Acute inhibition of COPI complex recruitment to the Golgi apparatus with pharmacological compounds failed to recapitulate the same entry defects as observed with the COPI-depleted cells but did result in specific decreases in viral membrane protein expression and assembly, leading to defects in progeny virion production. Taken together, our findings suggest that COPI complexes likely function indirectly in influenza virus entry but play direct roles in viral membrane protein expression and assembly. PMID:23255804

  8. Genome plasticity of triple-reassortant H1N1 influenza A virus during infection of vaccinated pigs

    PubMed Central

    Diaz, Andres; Enomoto, Shinichiro; Romagosa, Anna; Sreevatsan, Srinand; Nelson, Martha; Culhane, Marie

    2015-01-01

    To gain insight into the evolution of influenza A viruses (IAVs) during infection of vaccinated pigs, we experimentally infected a 3-week-old naive pig with a triple-reassortant H1N1 IAV and placed the seeder pig in direct contact with a group of age-matched vaccinated pigs (n = 10). We indexed the genetic diversity and evolution of the virus at an intra-host level by deep sequencing the entire genome directly from nasal swabs collected at two separate samplings during infection. We obtained 13 IAV metagenomes from 13 samples, which included the virus inoculum and two samples from each of the six pigs that tested positive for IAV during the study. The infection produced a population of heterogeneous alleles (sequence variants) that was dynamic over time. Overall, 794 polymorphisms were identified amongst all samples, which yielded 327 alleles, 214 of which were unique sequences. A total of 43 distinct haemagglutinin proteins were translated, two of which were observed in multiple pigs, whereas the neuraminidase (NA) was conserved and only one dominant NA was found throughout the study. The genetic diversity of IAVs changed dynamically within and between pigs. However, most of the substitutions observed in the internal gene segments were synonymous. Our results demonstrated remarkable IAV diversity, and the complex, rapid and dynamic evolution of IAV during infection of vaccinated pigs that can only be appreciated with repeated sampling of individual animals and deep sequence analysis. PMID:26251306

  9. Genome plasticity of triple-reassortant H1N1 influenza A virus during infection of vaccinated pigs.

    PubMed

    Diaz, Andres; Enomoto, Shinichiro; Romagosa, Anna; Sreevatsan, Srinand; Nelson, Martha; Culhane, Marie; Torremorell, Montserrat

    2015-10-01

    To gain insight into the evolution of influenza A viruses (IAVs) during infection of vaccinated pigs, we experimentally infected a 3-week-old naive pig with a triple-reassortant H1N1 IAV and placed the seeder pig in direct contact with a group of age-matched vaccinated pigs (n = 10). We indexed the genetic diversity and evolution of the virus at an intra-host level by deep sequencing the entire genome directly from nasal swabs collected at two separate samplings during infection. We obtained 13 IAV metagenomes from 13 samples, which included the virus inoculum and two samples from each of the six pigs that tested positive for IAV during the study. The infection produced a population of heterogeneous alleles (sequence variants) that was dynamic over time. Overall, 794 polymorphisms were identified amongst all samples, which yielded 327 alleles, 214 of which were unique sequences. A total of 43 distinct haemagglutinin proteins were translated, two of which were observed in multiple pigs, whereas the neuraminidase (NA) was conserved and only one dominant NA was found throughout the study. The genetic diversity of IAVs changed dynamically within and between pigs. However, most of the substitutions observed in the internal gene segments were synonymous. Our results demonstrated remarkable IAV diversity, and the complex, rapid and dynamic evolution of IAV during infection of vaccinated pigs that can only be appreciated with repeated sampling of individual animals and deep sequence analysis. PMID:26251306

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. [Internal epidemic influenza virus proteins: isolation and investigation].

    PubMed

    Ivanova, V T; Rakutina, R O; Kordiukova, L V; Manykin, A A; Fedorova, N V; Ksenofontov, A L; Slepushkin, A N

    2006-01-01

    The internal influenza virus proteins M1 and RNP free from surface protein impurities were isolated from subviral particles (virions free from HA and NA ectomenes). The spikeless particles had no propensity to aggregate in the solution at pH 5.0 as compared with native viruses. The subviral particles of B/Hong Kong/330/01 influenza virus, which belonged to B/Victoria/2/87-lineage, were obtained by proteolytic treatment with the enzyme bromelain under the same conditions as in cases of influenza B viruses of B/Jamagata/16/88 lineage. A chromatographic analysis of the tryptic hydrolyzates obtained for matrix (M1) proteins of A(H1N1) and A(H3N2) influenza viruses revealed differences that were greatest between the protein M1 molecules isolated from influenza viruses of different subtypes of hemagglutinine. These findings suggest there are variations in the structure of this conservative internal viral protein M1 during evolution.

  16. 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

    2014-02-26

    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.

  17. 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 Central

    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

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

    PubMed Central

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

    2015-01-01

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

  20. 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

  1. 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.

  2. 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...

  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. 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

  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. Highly pathogenic avian influenza.

    PubMed

    Swayne, D E; Suarez, D L

    2000-08-01

    Highly pathogenic (HP) avian influenza (AI) (HPAI) is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus, family Orthomyxoviridae. However, most AI virus strains are mildly pathogenic (MP) and produce either subclinical infections or respiratory and/or reproductive diseases in a variety of domestic and wild bird species. Highly pathogenic avian influenza is a List A disease of the Office International des Epizooties, while MPAI is neither a List A nor List B disease. Eighteen outbreaks of HPAI have been documented since the identification of AI virus as the cause of fowl plague in 1955. Mildly pathogenic avian influenza viruses are maintained in wild aquatic bird reservoirs, occasionally crossing over to domestic poultry and causing outbreaks of mild disease. Highly pathogenic avian influenza viruses do not have a recognised wild bird reservoir, but can occasionally be isolated from wild birds during outbreaks in domestic poultry. Highly pathogenic avian influenza viruses have been documented to arise from MPAI viruses through mutations in the haemagglutinin surface protein. Prevention of exposure to the virus and eradication are the accepted methods for dealing with HPAI. Control programmes, which imply allowing a low incidence of infection, are not an acceptable method for managing HPAI, but have been used during some outbreaks of MPAI. The components of a strategy to deal with MPAI or HPAI include surveillance and diagnosis, biosecurity, education, quarantine and depopulation. Vaccination has been used in some control and eradication programmes for AI.

  8. Influenza-Like Illnesses in Senegal: Not Only Focus on Influenza Viruses

    PubMed Central

    Dia, Ndongo; Diene Sarr, Fatoumata; Thiam, Diamilatou; Faye Sarr, Tening; Espié, Emmanuelle; OmarBa, Ibrahim; Coly, Malang; Niang, Mbayame; Richard, Vincent

    2014-01-01

    Influenza surveillance in African countries was initially restricted to the identification of circulating strains. In Senegal, the network has recently been enhanced (i) to include epidemiological data from Dakar and other regions and (ii) to extend virological surveillance to other respiratory viruses. Epidemiological data from the sentinel sites is transmitted daily by mobile phone. The data include those for other febrile syndromes similar to influenza-like illnesses (ILI), corresponding to integrated approach. Also, clinical samples are randomly selected and analyzed for influenza and other respiratory viruses. There were 101,640 declared visits to the 11 sentinel sites between week 11-2012 and week 35-2013; 22% of the visits were for fever syndromes and 23% of the cases of fever syndrome were ILI. Influenza viruses were the second most frequent cause of ILI (20%), after adenoviruses (21%) and before rhinoviruses (18%) and enteroviruses (15%). Co-circulation and co-infection were frequent and were responsible for ILI peaks. The first months of implementation of the enhanced surveillance system confirmed that viruses other the influenza make large contributions to influenza-like illnesses. It is therefore important to consider these etiologies in the development of strategies to reduce respiratory infections. More informative tools and research studies are required to assess the burden of respiratory infections in developing countries. PMID:24675982

  9. 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

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

    PubMed

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

    2015-10-01

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

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

    PubMed

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

    2015-10-01

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

  12. 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

  13. Novel reassortant highly pathogenic avian influenza (H5N5) viruses in domestic ducks, China.

    PubMed

    Gu, Min; Liu, Wenbo; Cao, Yongzhong; Peng, Daxin; Wang, Xiaobo; Wan, Hongquan; Zhao, Guo; Xu, Quangang; Zhang, Wei; Song, Qingqing; Li, Yanfang; Liu, Xiufan

    2011-06-01

    In China, domestic ducks and wild birds often share the same water, in which influenza viruses replicate preferentially. Isolation of 2 novel reassortant highly pathogenic avian influenza (H5N5) viruses from apparently healthy domestic ducks highlights the role of these ducks as reassortment vessels. Such new subtypes of influenza viruses may pose a pandemic threat.

  14. 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.

  15. Attenuated influenza virus construct with enhanced hemagglutinin protein expression.

    PubMed

    Maamary, Jad; Pica, Natalie; Belicha-Villanueva, Alan; Chou, Yi-ying; Krammer, Florian; Gao, Qinshan; García-Sastre, Adolfo; Palese, Peter

    2012-05-01

    Influenza A viruses encoding an altered viral NS1 protein have emerged as promising live attenuated vaccine platforms. A carboxy-terminal truncation in the NS1 protein compromises its interferon antagonism activity, making these viruses attenuated in the host yet still able to induce protection from challenge with wild-type viruses. However, specific viral protein expression by NS1-truncated viruses is known to be decreased in infected cells. In this report, we show that recombinant H5N1 and H1N1 influenza viruses encoding a truncated NS1 protein expressed lower levels of hemagglutinin (HA) protein in infected cells than did wild-type viruses. This reduction in HA protein expression correlated with a reduction in HA mRNA levels in infected cells. NS1 truncation affected the expression of HA protein but not that of the nucleoprotein (NP). This segment specificity was mapped to the terminal sequences of their specific viral RNAs. Since the HA protein is the major immunogenic component in influenza virus vaccines, we sought to restore its expression levels in NS1-truncated viruses in order to improve their vaccine efficacy. For this purpose, we generated an NS1-truncated recombinant influenza A/Puerto Rico/8/34 (rPR8) virus carrying the G3A C8U "superpromoter" mutations in the HA genomic RNA segment. This strategy retained the attenuation properties of the recombinant virus but enhanced the expression level of HA protein in infected cells. Finally, mice immunized with rPR8 viruses encoding a truncated NS1 protein and carrying the G3A C8U mutations in the HA segment demonstrated enhanced protection from wild-type virus challenge over that for mice vaccinated with an rPR8 virus encoding the truncated NS1 protein alone.

  16. 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...

  17. 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...

  18. 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

  19. Emerging antiviral strategies to interfere with influenza virus entry.

    PubMed

    Vanderlinden, Evelien; Naesens, Lieve

    2014-03-01

    Influenza A and B viruses are highly contagious respiratory pathogens with a considerable medical and socioeconomical burden and known pandemic potential. Current influenza vaccines require annual updating and provide only partial protection in some risk groups. Due to the global spread of viruses with resistance to the M2 proton channel inhibitor amantadine or the neuraminidase inhibitor oseltamivir, novel antiviral agents with an original mode of action are urgently needed. We here focus on emerging options to interfere with the influenza virus entry process, which consists of the following steps: attachment of the viral hemagglutinin to the sialylated host cell receptors, endocytosis, M2-mediated uncoating, low pH-induced membrane fusion, and, finally, import of the viral ribonucleoprotein into the nucleus. We review the current functional and structural insights in the viral and cellular components of this entry process, and the diverse antiviral strategies that are being explored. This encompasses small molecule inhibitors as well as macromolecules such as therapeutic antibodies. There is optimism that at least some of these innovative concepts to block influenza virus entry will proceed from the proof of concept to a more advanced stage. Special attention is therefore given to the challenging issues of influenza virus (sub)type-dependent activity or potential drug resistance. PMID:23801557

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. Bacterial sinusitis and otitis media following influenza virus infection in ferrets.

    PubMed

    Peltola, Ville T; Boyd, Kelli L; McAuley, Julie L; Rehg, Jerold E; McCullers, Jonathan A

    2006-05-01

    Streptococcus pneumoniae is the leading cause of otitis media, sinusitis, and pneumonia. Many of these infections result from antecedent influenza virus infections. In this study we sought to determine whether the frequency and character of secondary pneumococcal infections differed depending on the strain of influenza virus that preceded bacterial challenge. In young ferrets infected with influenza virus and then challenged with pneumococcus, influenza viruses of any subtype increased bacterial colonization of the nasopharynx. Nine out of 10 ferrets infected with H3N2 subtype influenza A viruses developed either sinusitis or otitis media, while only 1 out of 11 ferrets infected with either an H1N1 influenza A virus or an influenza B virus did so. These data may partially explain why bacterial complication rates are higher during seasons when H3N2 viruses predominate. This animal model will be useful for further study of the mechanisms that underlie viral-bacterial synergism.

  7. 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

  8. Animal models for influenza viruses: implications for universal vaccine development.

    PubMed

    Margine, Irina; Krammer, Florian

    2014-10-21

    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.

  9. Inhibition of glycoprotein oligosaccharide processing in vitro and in influenza-virus-infected cells by alpha-D-mannopyranosylmethyl-p-nitrophenyltriazene.

    PubMed Central

    McDowell, W; Tlusty, A; Rott, R; BeMiller, J N; Bohn, J A; Meyers, R W; Schwarz, R T

    1988-01-01

    The effects of alpha-D-mannopyranosylmethyl-p-nitrophenyltriazene (MMNT) on mannosidases involved in asparagine-linked oligosaccharide processing were investigated. MMNT was found to inhibit the activity of rat liver Golgi alpha-mannosidase I in a concentration-dependent manner (50% inhibition with 0.18 mM-MMNT), whereas rat liver endoplasmic-reticulum alpha-mannosidase appeared to be resistant (less than 5% inhibition at 1 mM-MMNT). Jack-bean alpha-mannosidase was also sensitive to inhibition by MMNT (50% inhibition with 0.32 mM-MMNT). Treatment of influenza-virus-infected chick-embryo cells with 1 mM-MMNT led to a decrease in the formation of complex-type asparagine-linked oligosaccharides and an accumulation of high-mannose-type oligosaccharides with the composition Man8(GlcNAc)2 and Man7(GlcNAc)2 on the viral glycoproteins. The biological activities of influenza-virus haemagglutinin and neuraminidase synthesized in the presence of 1 mM-MMNT remained unchanged, but the virus was less infectious than the control. PMID:3214435

  10. Influenza virus induces bacterial and nonbacterial otitis media.

    PubMed

    Short, Kirsty R; Diavatopoulos, Dimitri A; Thornton, Ruth; Pedersen, John; Strugnell, Richard A; Wise, Andrew K; Reading, Patrick C; Wijburg, Odilia L

    2011-12-15

    Otitis media (OM) is one of the most common childhood diseases. OM can arise when a viral infection enables bacteria to disseminate from the nasopharynx to the middle ear. Here, we provide the first infant murine model for disease. Mice coinfected with Streptococcus pneumoniae and influenza virus had high bacterial load in the middle ear, middle ear inflammation, and hearing loss. In contrast, mice colonized with S. pneumoniae alone had significantly less bacteria in the ear, minimal hearing loss, and no inflammation. Of interest, infection with influenza virus alone also caused some middle ear inflammation and hearing loss. Overall, this study provides a clinically relevant and easily accessible animal model to study the pathogenesis and prevention of OM. Moreover, we provide, to our knowledge, the first evidence that influenza virus alone causes middle ear inflammation in infant mice. This inflammation may then play an important role in the development of bacterial OM.

  11. 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.

  12. 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

  13. Localization of influenza virus sialoreceptors in equine respiratory tract.

    PubMed

    Scocco, Paola; Pedini, Vera

    2008-08-01

    This study was performed to identify the equine respiratory tract areas which express the specific receptor for equine influenza virus; findings may be useful to provide new ways to treat the infectious disease. The present work aims to visualize in situ the presence of sialoderivatives in the horse respiratory tract in order to localize sialoderivatives acting as influenza virus receptors. To this purpose, nasal mucosae, trachea, bronchus and lung parenchyma were removed from 8 mature horses of both sexes. We performed sialic acid characterization by means of mild and strong periodate oxidation and saponification, combined with lectin histochemistry and sialidase digestion, in addition to the direct evidentiation of sialic acid residues. No differences were shown between sexes. Sialic acid residues are present in the nasal mucous cell secretion, where they are linked to galactose by means of alpha2-3 linkage and are mainly C9 acetylated, and in the nasal and tracheal epithelial lining, where they are represented by periodate labile residues (alpha2-3)- and/or (alpha2-6)- linked to galactose. Specific receptors for equine influenza viruses are present at the nasal and tracheal epithelial lining cell coat levels, and in some trachea epithelial cells, but the horse possesses a preventive defence, which consists of the secretion of a mucous layer at nasal level, which could specifically inactivate the hemagglutinins of equine influenza virus; in addition, it expresses other sialoreceptors which can mask the influenza specific ones.

  14. Human Monoclonal Antibodies Broadly Neutralizing against Influenza B Virus

    PubMed Central

    Yasugi, Mayo; Kubota-Koketsu, Ritsuko; Yamashita, Akifumi; Kawashita, Norihito; Du, Anariwa; Sasaki, Tadahiro; Nishimura, Mitsuhiro; Misaki, Ryo; Kuhara, Motoki; Boonsathorn, Naphatsawan; Fujiyama, Kazuhito; Okuno, Yoshinobu; Nakaya, Takaaki; Ikuta, Kazuyoshi

    2013-01-01

    Influenza virus has the ability to evade host immune surveillance through rapid viral genetic drift and reassortment; therefore, it remains a continuous public health threat. The development of vaccines producing broadly reactive antibodies, as well as therapeutic strategies using human neutralizing monoclonal antibodies (HuMAbs) with global reactivity, has been gathering great interest recently. Here, three hybridoma clones producing HuMAbs against influenza B virus, designated 5A7, 3A2 and 10C4, were prepared using peripheral lymphocytes from vaccinated volunteers, and were investigated for broad cross-reactive neutralizing activity. Of these HuMAbs, 3A2 and 10C4, which recognize the readily mutable 190-helix region near the receptor binding site in the hemagglutinin (HA) protein, react only with the Yamagata lineage of influenza B virus. By contrast, HuMAb 5A7 broadly neutralizes influenza B strains that were isolated from 1985 to 2006, belonging to both Yamagata and Victoria lineages. Epitope mapping revealed that 5A7 recognizes 316G, 318C and 321W near the C terminal of HA1, a highly conserved region in influenza B virus. Indeed, no mutations in the amino acid residues of the epitope region were induced, even after the virus was passaged ten times in the presence of HuMAb 5A7. Moreover, 5A7 showed significant therapeutic efficacy in mice, even when it was administered 72 hours post-infection. These results indicate that 5A7 is a promising candidate for developing therapeutics, and provide insight for the development of a universal vaccine against influenza B virus. PMID:23408886

  15. Reassortment ability of the 2009 pandemic H1N1 influenza virus with circulating human and avian influenza viruses: public health risk implications.

    PubMed

    Stincarelli, Maria; Arvia, Rosaria; De Marco, Maria Alessandra; Clausi, Valeria; Corcioli, Fabiana; Cotti, Claudia; Delogu, Mauro; Donatelli, Isabella; Azzi, Alberta; Giannecchini, Simone

    2013-08-01

    Exploring the reassortment ability of the 2009 pandemic H1N1 (A/H1N1pdm09) influenza virus with other circulating human or avian influenza viruses is the main concern related to the generation of more virulent or new variants having implications for public health. After different coinfection experiments in human A549 cells, by using the A/H1N1pdm09 virus plus one of human seasonal influenza viruses of H1N1 and H3N2 subtype or one of H11, H10, H9, H7 and H1 avian influenza viruses, several reassortant viruses were obtained. Among these, the HA of H1N1 was the main segment of human seasonal influenza virus reassorted in the A/H1N1pdm09 virus backbone. Conversely, HA and each of the three polymerase segments, alone or in combination, of the avian influenza viruses mainly reassorted in the A/H1N1pdm09 virus backbone. Of note, A/H1N1pdm09 viruses that reassorted with HA of H1N1 seasonal human or H11N6 avian viruses or carried different combination of avian origin polymerase segments, exerted a higher replication effectiveness than that of the parental viruses. These results confirm that reassortment of the A/H1N1pdm09 with circulating low pathogenic avian influenza viruses should not be misjudged in the prediction of the next pandemic.

  16. Infection with A2 Hong Kong influenza virus in domestic cats.

    PubMed

    Paniker, C K; Nair, C M

    1970-01-01

    The antigenic relationship of A2 Hong Kong influenza virus with equine influenza virus, and its ability to infect horses and baboons, have led to studies on the susceptibility of domestic animals to the virus.In this study it was found that cats could be infected with A2 Hong Kong influenza virus by intranasal inoculation or by contact with an infected cat or with a human influenza patient. There was no clinical illness, but infected animals shed the virus from the throat for 1 week and developed haemagglutination-inhibiting antibodies. A survey of normal cat sera showed that 6 out of 28 sera inhibited haemagglutination by A2 Hong Kong influenza virus.The results suggest that domestic cats may act as vectors in the transmission of influenza virus. Experimental infection in cats may be used as a laboratory model for influenza.

  17. Infection with A2 Hong Kong influenza virus in domestic cats*

    PubMed Central

    Paniker, C. K. J.; Nair, C. M. G.

    1970-01-01

    The antigenic relationship of A2 Hong Kong influenza virus with equine influenza virus, and its ability to infect horses and baboons, have led to studies on the susceptibility of domestic animals to the virus. In this study it was found that cats could be infected with A2 Hong Kong influenza virus by intranasal inoculation or by contact with an infected cat or with a human influenza patient. There was no clinical illness, but infected animals shed the virus from the throat for 1 week and developed haemagglutination-inhibiting antibodies. A survey of normal cat sera showed that 6 out of 28 sera inhibited haemagglutination by A2 Hong Kong influenza virus. The results suggest that domestic cats may act as vectors in the transmission of influenza virus. Experimental infection in cats may be used as a laboratory model for influenza. PMID:5314017

  18. Adaptation of a Duck Influenza A Virus in Quail

    PubMed Central

    Yamada, Shinya; Shinya, Kyoko; Takada, Ayato; Ito, Toshihiro; Suzuki, Takashi; Suzuki, Yasuo; Le, Quynh Mai; Ebina, Masahito; Kasai, Noriyuki; Kida, Hiroshi; Horimoto, Taisuke; Rivailler, Pierre; Chen, Li Mei; Donis, Ruben O.

    2012-01-01

    Quail are thought to serve as intermediate hosts of influenza A viruses between aquatic birds and terrestrial birds, such as chickens, due to their high susceptibility to aquatic-bird viruses, which then adapt to replicate efficiently in their new hosts. However, does replication of aquatic-bird influenza viruses in quail similarly result in their efficient replication in humans? Using sialic acid-galactose linkage-specific lectins, we found both avian (sialic acid-α2-3-galactose [Siaα2-3Gal] linkages on sialyloligosaccharides)- and human (Siaα2-6Gal)-type receptors on the tracheal cells of quail, consistent with previous reports. We also passaged a duck H3N2 virus in quail 19 times. Sequence analysis revealed that eight mutations accumulated in hemagglutinin (HA) during these passages. Interestingly, many of the altered HA amino acids found in the adapted virus are present in human seasonal viruses, but not in duck viruses. We also found that stepwise stalk deletion of neuraminidase occurred during passages, resulting in reduced neuraminidase function. Despite some hemagglutinin mutations near the receptor binding pocket, appreciable changes in receptor specificity were not detected. However, reverse-genetics-generated viruses that possessed the hemagglutinin and neuraminidase of the quail-passaged virus replicated significantly better than the virus possessing the parent HA and neuraminidase in normal human bronchial epithelial cells, whereas no significant difference in replication between the two viruses was observed in duck cells. Further, the quail-passaged but not the original duck virus replicated in human bronchial epithelial cells. These data indicate that quail can serve as intermediate hosts for aquatic-bird influenza viruses to be transmitted to humans. PMID:22090115

  19. Ecological Factors Driving Avian Influenza Virus Dynamics in Spanish Wetland Ecosystems

    PubMed Central

    Pérez-Ramírez, Elisa; Acevedo, Pelayo; Allepuz, Alberto; Gerrikagoitia, Xeider; Alba, Anna; Busquets, Núria; Díaz-Sánchez, Sandra; Álvarez, Vega; Abad, Francesc Xavier; Barral, Marta; Majó, Natàlia; Höfle, Ursula

    2012-01-01

    Studies exploring the ecological interactions between avian influenza viruses (AIV), natural hosts and the environment are scarce. Most work has focused on viral survival and transmission under laboratory conditions and through mathematical modelling. However, more integrated studies performed under field conditions are required to validate these results. In this study, we combined information on bird community, environmental factors and viral epidemiology to assess the contribution of biotic and abiotic factors in the occurrence of low pathogenic AIV in Spanish wetlands. For that purpose, seven locations in five different wetlands were studied during two years (2007–2009), including seven sampling visits by location. In each survey, fresh faeces (n = 4578) of wild birds and water samples were collected for viral detection. Also, the vegetation structure, water physical properties of wetlands, climatic conditions and wild bird community composition were determined. An overall AIV prevalence of 1.7%±0.4 was detected in faecal samples with important fluctuations among seasons and locations. Twenty-six AIV were isolated from the 78 RRT-PCR positive samples and eight different haemagglutinines and five neuraminidases were identified, being the combination H3N8 the most frequent. Variation partitioning procedures identified the combination of space and time variables as the most important pure factor – independently to other factors – explaining the variation in AIV prevalence (36.8%), followed by meteorological factor (21.5%) and wild bird community composition/vegetation structure (21.1%). These results contribute to the understanding of AIV ecological drivers in Spanish ecosystems and provide useful guidelines for AIV risk assessment identifying potential hotspots of AIV activity. PMID:23152749

  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.

  1. 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

  2. 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

  3. [An influenza outbreak of type A and type B influenza viruses].

    PubMed

    Profeta, M L; Pontello, M; Zanchetta, N

    1983-03-31

    Results of investigations carried out during an outbreak of influenza occurred in January 1981 in a School of Milan are reported and discussed. A total of 9 type A (H1N1) influenza virus strains, antigenically intermediate between A/USSR/90/77 and A/Brazil/11/78 variants, and 2 type B influenza virus strains, antigenically intermediate between B/Hong Kong/8/73 and B/Singapore/222/79 variants, have been isolated. In one case both epidemic strains have been simultaneously detected. From the results of type-specific complement-fixing antibody titration it appears that an influenza virus infection occurred in 64% of the 300 subjects serologically examined. In 43% of the cases type A strain was involved, in 12% type B strain and in 9% both serotypes. Judging from the data of school absenteeism it seems that infections by type A virus were more severe than those by type B virus. Finally, because a group of pupils attending the school had been vaccinated in December 1978, it has been demonstrated that the rate of type A presumptive infections was correlated to the hemagglutination-inhibiting antibody titers attained after vaccination.

  4. 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

  5. Novel reassortant influenza A(H5N8) viruses in domestic ducks, eastern China.

    PubMed

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

    2014-08-01

    Domestic ducks are natural reservoirs of avian influenza viruses and serve as reassortant hosts for new virus subtypes. We isolated 2 novel influenza A(H5N8) viruses from domestic ducks in eastern China, sequenced their genomes, and tested their pathogenicity in chickens and mice. Circulation of these viruses may pose health risks for humans.

  6. 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

    2015-12-30

    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.

  7. 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

  8. 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

  9. Influenza Virus and Chromatin: Role of the CHD1 Chromatin Remodeler in the Virus Life Cycle

    PubMed Central

    Marcos-Villar, Laura; Pazo, Alejandra

    2016-01-01

    ABSTRACT Influenza A virus requires ongoing cellular transcription to carry out the cap-snatching process. Chromatin remodelers modify chromatin structure to produce an active or inactive conformation, which enables or prevents the recruitment of transcriptional complexes to specific genes; viral transcription thus depends on chromatin dynamics. Influenza virus polymerase associates with chromatin components of the infected cell, such as RNA polymerase II (RNAP II) or the CHD6 chromatin remodeler. Here we show that another CHD family member, CHD1 protein, also interacts with the influenza virus polymerase complex. CHD1 recognizes the H3K4me3 (histone 3 with a trimethyl group in lysine 4) histone modification, a hallmark of active chromatin. Downregulation of CHD1 causes a reduction in viral polymerase activity, viral RNA transcription, and the production of infectious particles. Despite the dependence of influenza virus on cellular transcription, RNAP II is degraded when viral transcription is complete, and recombinant viruses unable to degrade RNAP II show decreased pathogenicity in the murine model. We describe the CHD1–RNAP II association, as well as the parallel degradation of both proteins during infection with viruses showing full or reduced induction of degradation. The H3K4me3 histone mark also decreased during influenza virus infection, whereas a histone mark of inactive chromatin, H3K27me3, remained unchanged. Our results indicate that CHD1 is a positive regulator of influenza virus multiplication and suggest a role for chromatin remodeling in the control of the influenza virus life cycle. IMPORTANCE Although influenza virus is not integrated into the genome of the infected cell, it needs continuous cellular transcription to synthesize viral mRNA. This mechanism implies functional association with host genome expression and thus depends on chromatin dynamics. Influenza virus polymerase associates with transcription-related factors, such as RNA

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. Avian influenza virus isolation, propagation, and titration in embryonated chicken eggs.

    PubMed

    Spackman, Erica; Killian, Mary Lea

    2014-01-01

    Avian influenza virus and some mammalian influenza A viruses are usually isolated, propagated, and titrated in embryonated chicken eggs (ECE). Most any sample type can be accommodated for culture with appropriate processing. Isolation may also be accomplished in cell culture particularly if mammalian lineage isolates are suspected, for example, swine influenza in turkey specimens. Culture is highly sensitive, but is not specific for influenza A, which may be an advantage because a sample may be screened for several agents at once. Once an agent is isolated in culture, the presence of influenza viruses is confirmed with any of several assays. The methods for propagating virus isolates in ECE are described.

  17. 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

  18. 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

  19. 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

  20. Exploring naphthyl-carbohydrazides as inhibitors of influenza A viruses.

    PubMed

    Barman, Sanmitra; You, Lei; Chen, Ran; Codrea, Vlad; Kago, Grace; Edupuganti, Ramakrishna; Robertus, Jon; Krug, Robert M; Anslyn, Eric V

    2014-01-01

    A library of hydrazide derivatives was synthesized to target non-structural protein 1 of influenza A virus (NS1) as a means to develop anti-influenza drug leads. The lead compound 3-hydroxy-N-[(Z)-1-(5,6,7,8-tetrahydronaphthalen-2-yl)ethylideneamino]naphthalene-2-carboxamide, which we denoted as "HENC", was identified by its ability to increase the melting temperature of the effector domain (ED) of the NS1 protein, as assayed using differential scanning fluorimetry. A library of HENC analogs was tested for inhibitory effect against influenza A virus replication in MDCK cells. A systematic diversification of HENC revealed the identity of the R group attached to the imine carbon atom significantly influenced the antiviral activity. A phenyl or cyclohexyl at this position yielded the most potent antiviral activity. The phenyl containing compound had antiviral activity similar to that of the active form of oseltamivir (Tamiflu), and had no detectable effect on cell viability.

  1. 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

  2. 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

  3. 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.

  4. N₂ gas plasma inactivates influenza virus mediated by oxidative stress.

    PubMed

    Sakudo, Akikazu; Misawa, Tatsuya; Shimizu, Naohiro; Imanishi, Yuichiro

    2014-01-01

    Here we show that N₂ gas plasma, produced by applying a short high-voltage pulse using a static induction (SI) thyristor power supply inactivates influenza virus. N₂ gas plasma treatment of influenza A and B viruses induced the degradation of viral proteins, including nucleoprotein, hemagglutinin, and neuraminidase. The injury of viral RNA genome and the inactivation of hemagglutination were also observed after N₂ gas plasma treatment. These changes were possibly due to changes in the viral envelope, because modification of the lipid content was also suggested by Fourier-transformed infrared spectroscopy. At least three major mechanisms of action (heat, UV-A, and oxidative stress (i.e. hydrogen peroxide-like molecules)) were found in this system. Among them, oxidative stress appeared to be the main factor in the inactivation of influenza virus. In addition, there was an increase in the nitrotyrosine content of viral proteins, suggesting that oxidative stress produced by N₂ gas plasma generation oxidized proteins. As a result, oxidation may be the most important factor in the inactivation, degradation, and modification of influenza virus by N₂ gas plasma. PMID:24389143

  5. Decay of Influenza a Viruses of Human and Avian Origin

    PubMed Central

    Mitchell, Chas. A.; Guerin, L. F.; Robillard, John

    1968-01-01

    The decay rate of six strains of Influenza virus Type A of human origin and eight strains of avian origin were examined in aerosol form under fixed conditions of temperature and humidity. Strains of avian origin were demonstrated to have greater resistance to decay of viability. PMID:4234786

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. 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...

  14. 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...

  15. 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.

  16. 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...

  17. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. Detection of evolutionarily distinct avian influenza a viruses in antarctica.

    PubMed

    Hurt, Aeron C; 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. IMPORTANCE Avian influenza viruses (AIVs) are typically maintained and spread by migratory birds, resulting in the existence of distinctly different viruses around the world. However, AIVs have not previously been detected in Antarctica. In this study, we

  5. Detection of evolutionarily distinct avian influenza a viruses in antarctica.

    PubMed

    Hurt, Aeron C; 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. IMPORTANCE Avian influenza viruses (AIVs) are typically maintained and spread by migratory birds, resulting in the existence of distinctly different viruses around the world. However, AIVs have not previously been detected in Antarctica. In this study, we

  6. Single Fluorescence Channel-based Multiplex Detection of Avian Influenza Virus by Quantitative PCR with Intercalating Dye.

    PubMed

    Ahberg, Christian D; Manz, Andreas; Neuzil, Pavel

    2015-01-01

    Since its invention in 1985 the polymerase chain reaction (PCR) has become a well-established method for amplification and detection of segments of double-stranded DNA. Incorporation of fluorogenic probe or DNA intercalating dyes (such as SYBR Green) into the PCR mixture allowed real-time reaction monitoring and extraction of quantitative information (qPCR). Probes with different excitation spectra enable multiplex qPCR of several DNA segments using multi-channel optical detection systems. Here we show multiplex qPCR using an economical EvaGreen-based system with single optical channel detection. Previously reported non quantitative multiplex real-time PCR techniques based on intercalating dyes were conducted once the PCR is completed by performing melting curve analysis (MCA). The technique presented in this paper is both qualitative and quantitative as it provides information about the presence of multiple DNA strands as well as the number of starting copies in the tested sample. Besides important internal control, multiplex qPCR also allows detecting concentrations of more than one DNA strand within the same sample. Detection of the avian influenza virus H7N9 by PCR is a well established method. Multiplex qPCR greatly enhances its specificity as it is capable of distinguishing both haemagglutinin (HA) and neuraminidase (NA) genes as well as their ratio.

  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. 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.

  9. Genetic and antigenic characteristics of H4 subtype avian influenza viruses in Korea and their pathogenicity in quails, domestic ducks and mice.

    PubMed

    Kang, Hyun-Mi; Choi, Jun-Gu; Kim, Kwang-Il; Park, Ha-Young; Park, Choi-Kyu; Lee, Youn-Jeong

    2013-01-01

    In Korea, a nationwide surveillance programme was implemented in 2003 to identify highly pathogenic avian influenza viruses (AIVs). AIVs belonging to one of the most common haemagglutinin subtypes, H4, were isolated from two domestic ducks and 52 wild birds between 2004 and 2010. These H4 AIVs could be further classified into three neuraminidase subtypes: H4N6 (94.4%), H4N2 (3.7%) and H4N3 (1.9%). Phylogenetic analysis revealed that the H4 AIVs had a variety of genetic constellations, with at least nine different genotypes represented. The pathogenicity of these H4 viruses was assessed in quails, domestic ducks and mice. None of the H4 AIVs induced clinical signs in quails or domestic ducks. Viral shedding in quails was relatively high, and virus was recovered up to 5-7 days post-inoculation (p.i.) in oropharyngeal swabs, but the viruses replicated poorly in domestic ducks. Quails may act as an intermediate host in which AIVs are amplified and transmitted to other species. In mice, all of the AIVs were recovered efficiently at relatively high titres from the lungs up to 7 days p.i., demonstrating the potential for AIVs to infect mice directly without prior adaptation. None of the AIVs induced clinical signs nor was any lethal to infected mice. However, there was significant loss of body weight in mice infected with viruses of duck origin. It is suggested that the active surveillance of influenza viruses needs to be enhanced in domestic poultry as well as in wild birds, and that it should include assessment of pathogenicity in animal models.

  10. Evasion of Influenza A Viruses from Innate and Adaptive Immune Responses

    PubMed Central

    van de Sandt, Carolien E.; Kreijtz, Joost H. C. M.; Rimmelzwaan, Guus F.

    2012-01-01

    The influenza A virus is one of the leading causes of respiratory tract infections in humans. Upon infection with an influenza A virus, both innate and adaptive immune responses are induced. Here we discuss various strategies used by influenza A viruses to evade innate immune responses and recognition by components of the humoral and cellular immune response, which consequently may result in reduced clearing of the virus and virus-infected cells. Finally, we discuss how the current knowledge about immune evasion can be used to improve influenza A vaccination strategies. PMID:23170167

  11. Human influenza viruses and CD8(+) T cell responses.

    PubMed

    Grant, Emma J; Quiñones-Parra, Sergio M; Clemens, E Bridie; Kedzierska, Katherine

    2016-02-01

    Influenza A viruses (IAVs) cause significant morbidity and mortality worldwide, despite new strain-specific vaccines being available annually. As IAV-specific CD8(+) T cells promote viral control in the absence of neutralizing antibodies, and can mediate cross-reactive immunity toward distinct IAVs to drive rapid recovery from both mild and severe influenza disease, there is great interest in developing a universal T cell vaccine. However, despite detailed studies in mouse models of influenza virus infection, there is still a paucity of data on human epitope-specific CD8(+) T cell responses to IAVs. This review focuses on our current understanding of human CD8(+) T cell immunity against distinct IAVs and discusses the possibility of achieving a CD8(+) T cell mediated-vaccine that protects against multiple, distinct IAV strains across diverse human populations. We also review the importance of CD8(+) T cell immunity in individuals highly susceptible to severe influenza infection, including those hospitalised with influenza, the elderly and Indigenous populations.

  12. Influenza and other respiratory viruses detected by influenza-like illness surveillance in Leyte Island, the Philippines, 2010-2013.

    PubMed

    Otomaru, Hirono; Kamigaki, Taro; Tamaki, Raita; Opinion, Jamie; Santo, Arlene; Daya, Edgard; Okamoto, Michiko; Saito, Mariko; Tallo, Veronica; Lupisan, Soccoro; Suzuki, Akira; Oshitani, Hitoshi

    2015-01-01

    This study aimed to determine the role of influenza-like illness (ILI) surveillance conducted on Leyte Island, the Philippines, including involvement of other respiratory viruses, from 2010 to 2013. ILI surveillance was conducted from January 2010 to March 2013 with 3 sentinel sites located in Tacloban city, Palo and Tanauan of Leyte Island. ILI was defined as fever ≥38°C or feverish feeling and either cough or running nose in a patient of any age. Influenza virus and other 5 respiratory viruses were searched. A total of 5,550 ILI cases visited the 3 sites and specimens were collected from 2,031 (36.6%) cases. Among the cases sampled, 1,637 (75.6%) were children aged <5 years. 874 (43.0%) cases were positive for at least one of the respiratory viruses tested. Influenza virus and respiratory syncytial virus (RSV) were predominantly detected (both were 25.7%) followed by human rhinovirus (HRV) (17.5%). The age distributions were significantly different between those who were positive for influenza, HRV, and RSV. ILI cases were reported throughout the year and influenza virus was co-detected with those viruses on approximately half of the weeks of study period (RSV in 60.5% and HRV 47.4%). In terms of clinical manifestations, only the rates of headache and sore throat were significantly higher in influenza positive cases than cases positive to other viruses. In conclusion, syndromic ILI surveillance in this area is difficult to detect the start of influenza epidemic without laboratory confirmation which requires huge resources. Age was an important factor that affected positive rates of influenza and other respiratory viruses. Involvement of older age children may be useful to detect influenza more effectively. PMID:25893441

  13. Influenza and Other Respiratory Viruses Detected by Influenza-Like Illness Surveillance in Leyte Island, the Philippines, 2010–2013

    PubMed Central

    Otomaru, Hirono; Kamigaki, Taro; Tamaki, Raita; Opinion, Jamie; Santo, Arlene; Daya, Edgard; Okamoto, Michiko; Saito, Mariko; Tallo, Veronica; Lupisan, Soccoro; Suzuki, Akira; Oshitani, Hitoshi

    2015-01-01

    This study aimed to determine the role of influenza-like illness (ILI) surveillance conducted on Leyte Island, the Philippines, including involvement of other respiratory viruses, from 2010 to 2013. ILI surveillance was conducted from January 2010 to March 2013 with 3 sentinel sites located in Tacloban city, Palo and Tanauan of Leyte Island. ILI was defined as fever ≥38°C or feverish feeling and either cough or running nose in a patient of any age. Influenza virus and other 5 respiratory viruses were searched. A total of 5,550 ILI cases visited the 3 sites and specimens were collected from 2,031 (36.6%) cases. Among the cases sampled, 1,637 (75.6%) were children aged <5 years. 874 (43.0%) cases were positive for at least one of the respiratory viruses tested. Influenza virus and respiratory syncytial virus (RSV) were predominantly detected (both were 25.7%) followed by human rhinovirus (HRV) (17.5%). The age distributions were significantly different between those who were positive for influenza, HRV, and RSV. ILI cases were reported throughout the year and influenza virus was co-detected with those viruses on approximately half of the weeks of study period (RSV in 60.5% and HRV 47.4%). In terms of clinical manifestations, only the rates of headache and sore throat were significantly higher in influenza positive cases than cases positive to other viruses. In conclusion, syndromic ILI surveillance in this area is difficult to detect the start of influenza epidemic without laboratory confirmation which requires huge resources. Age was an important factor that affected positive rates of influenza and other respiratory viruses. Involvement of older age children may be useful to detect influenza more effectively. PMID:25893441

  14. 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

  15. Influenza virus surveillance, vaccine strain selection, and manufacture.

    PubMed

    Stöhr, Klaus; Bucher, Doris; Colgate, Tony; Wood, John

    2012-01-01

    As outlined in other chapters, the influenza virus, existing laboratory diagnostic abilities, and disease epidemiology have several peculiarities that impact on the timing and processes for the annual production of influenza vaccines. The chapter provides an overview on the key biological and other factors that influence vaccine production. They are the reason for an "annual circle race" beginning with global influenza surveillance during the influenza season in a given year to the eventual supply of vaccines 12 months later in time before the next seasonal outbreak and so on. As influenza vaccines are needed for the Northern and Southern Hemisphere outbreaks in fall and spring, respectively, global surveillance and vaccine production has become a year round business. Its highlights are the WHO recommendations on vaccine strains in February and September and the eventual delivery of vaccine doses in time before the coming influenza season. In between continues vaccine strain and epidemiological surveillance, preparation of new high growth reassortments, vaccine seed strain preparation and development of standardizing reagents, vaccine bulk production, fill-finishing and vaccine release, and in some regions, clinical trials for regulatory approval.

  16. A Viable Recombinant Rhabdovirus Lacking Its Glycoprotein Gene and Expressing Influenza Virus Hemagglutinin and Neuraminidase Is a Potent Influenza Vaccine

    PubMed Central

    Ryder, Alex B.; Buonocore, Linda; Vogel, Leatrice; Nachbagauer, Raffael; Krammer, Florian

    2014-01-01

    ABSTRACT The emergence of novel influenza viruses that cause devastating human disease is an ongoing threat and serves as an impetus for the continued development of novel approaches to influenza vaccines. Influenza vaccine development has traditionally focused on producing humoral and/or cell-mediated immunity, often against the viral surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Here, we describe a new vaccine candidate that utilizes a replication-defective vesicular stomatitis virus (VSV) vector backbone that lacks the native G surface glycoprotein gene (VSVΔG). The expression of the H5 HA of an H5N1 highly pathogenic avian influenza virus (HPAIV), A/Vietnam/1203/04 (VN1203), and the NA of the mouse-adapted H1N1 influenza virus A/Puerto Rico/8/34 (PR8) in the VSVΔG vector restored the ability of the recombinant virus to replicate in cell culture, without the requirement for the addition of trypsin. We show here that this recombinant virus vaccine candidate was nonpathogenic in mice when given by either the intramuscular or intranasal route of immunization and that the in vivo replication of VSVΔG-H5N1 is profoundly attenuated. This recombinant virus also provided protection against lethal H5N1 infection after a single dose. This novel approach to vaccination against HPAIVs may be widely applicable to other emerging strains of influenza virus. IMPORTANCE Preparation for a potentially catastrophic influenza pandemic requires novel influenza vaccines that are safe, can be produced and administered quickly, and are effective, both soon after administration and for a long duration. We have created a new influenza vaccine that utilizes an attenuated vesicular stomatitis virus (VSV) vector, to deliver and express influenza virus proteins against which vaccinated animals develop potent antibody responses. The influenza virus hemagglutinin and neuraminidase proteins, expressed on the surface of VSV particles, allowed this vaccine to grow in cell

  17. 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

  18. 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

  19. 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

  20. Targeting Cell Division Cycle 25 Homolog B To Regulate Influenza Virus Replication

    PubMed Central

    Perwitasari, Olivia; Torrecilhas, Ana Claudia; Yan, Xiuzhen; Johnson, Scott; White, Caleb; Tompkins, S. Mark

    2013-01-01

    Influenza virus is a worldwide global health concern causing seasonal morbidity mortality and economic burden. Chemotherapeutics is available; however, rapid emergence of drug-resistant influenza virus strains has reduced its efficacy. Thus, there is a need to discover novel antiviral agents. In this study, RNA interference (RNAi) was used to screen host genes required for influenza virus replication. One pro-influenza virus host gene identified was dual-specificity phosphatase cell division cycle 25 B (CDC25B). RNAi screening of CDC25B resulted in reduced influenza A virus replication, and a CDC25B small-molecule inhibitor (NSC95397) inhibited influenza A virus replication in a dose-dependent fashion. Viral RNA synthesis was reduced by NSC95397 in favor of increased beta interferon (IFN-β) expression, and NSC95397 was found to interfere with nuclear localization and chromatin association of NS1, an influenza virus protein. As NS1 has been shown to be chromatin associated and to suppress host transcription, it is likely that CDC25B supports NS1 nuclear function to hijack host transcription machinery in favor of viral RNA synthesis, a process that is blocked by NSC95397. Importantly, NSC95397 treatment protects mice against lethal influenza virus challenge. The findings establish CDC25B as a pro-influenza A virus host factor that may be targeted as a novel influenza A therapeutic strategy. PMID:24109234

  1. Targeting cell division cycle 25 homolog B to regulate influenza virus replication.

    PubMed

    Perwitasari, Olivia; Torrecilhas, Ana Claudia; Yan, Xiuzhen; Johnson, Scott; White, Caleb; Tompkins, S Mark; Tripp, Ralph A

    2013-12-01

    Influenza virus is a worldwide global health concern causing seasonal morbidity mortality and economic burden. Chemotherapeutics is available; however, rapid emergence of drug-resistant influenza virus strains has reduced its efficacy. Thus, there is a need to discover novel antiviral agents. In this study, RNA interference (RNAi) was used to screen host genes required for influenza virus replication. One pro-influenza virus host gene identified was dual-specificity phosphatase cell division cycle 25 B (CDC25B). RNAi screening of CDC25B resulted in reduced influenza A virus replication, and a CDC25B small-molecule inhibitor (NSC95397) inhibited influenza A virus replication in a dose-dependent fashion. Viral RNA synthesis was reduced by NSC95397 in favor of increased beta interferon (IFN-β) expression, and NSC95397 was found to interfere with nuclear localization and chromatin association of NS1, an influenza virus protein. As NS1 has been shown to be chromatin associated and to suppress host transcription, it is likely that CDC25B supports NS1 nuclear function to hijack host transcription machinery in favor of viral RNA synthesis, a process that is blocked by NSC95397. Importantly, NSC95397 treatment protects mice against lethal influenza virus challenge. The findings establish CDC25B as a pro-influenza A virus host factor that may be targeted as a novel influenza A therapeutic strategy.

  2. 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

  3. 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

  4. 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

  5. Molecular cloning of complementary DNA to Newcastle disease virus, and nucleotide sequence analysis of the junction between the genes encoding the haemagglutinin-neuraminidase and the large protein.

    PubMed

    Chambers, P; Millar, N S; Bingham, R W; Emmerson, P T

    1986-03-01

    Complementary DNA clones to 90% of the Newcastle disease virus (NDV) genome have been produced and mapped. These clones cover the entire HN, F and M genes, most if not all of the L gene and parts of the NP and P genes. The map of overlapping clones gives the gene order 3'-NP-P-M-F-HN-L-5' for NDV, identical to the gene order of Sendai virus, on the assumption that the NP gene of NDV is at the 3' end of the genome as previously suggested by inactivation of NDV transcription by u.v. light. The nucleotide sequence of 453 bases covering the junction between the HN and L genes has been determined. There is nucleotide sequence homology to the consensus polyadenylation and mRNA start sites of Sendai virus and vesicular stomatitis virus. The deduced amino acid sequence of the C terminus of the HN protein of NDV shows homology to the C-terminal amino acid sequences of the HN proteins of simian virus 5 and Sendai virus. An explanation for the presence of HN0, the precursor to HN in some strains of NDV, is suggested by the presence of a long non-coding region at the 3' terminus of the mRNA encoding the HN protein of NDV that could, by mutation, allow synthesis of a larger polypeptide.

  6. Polymeric inhibitor of influenza virus attachment protects mice from experimental influenza infection.

    PubMed

    Gambaryan, A S; Tuzikov, A B; Chinarev, A A; Juneja, L R; Bovin, N V; Matrosovich, M N

    2002-07-01

    Synthetic sialic acid-containing macromolecules inhibit influenza virus attachment to target cells and suppress the virus-mediated hemagglutination and neutralize virus infectivity in cell culture. To test the protective effects of attachment inhibitors in vivo, mice were infected with mouse-adapted influenza virus A/Aichi/2/68 (H3N2) and treated with synthetic polyacrylamide-based sialylglycopolymer PAA-YDS bearing moieties of (Neu5Acalpha2-6Galbeta1-4GlcNAcbeta1-2Manalpha1)2-3,6Manbeta1-4GlcNAcbeta1-4GlcNAc. Single intranasal inoculations with PAA-YDS 30 min before or 10 min after infection increased the survival of mice (P<0.01). Multiple treatments with aerosolized PAA-YDS on days 2-5 post infection also increased survival (P<0.01), alleviated disease symptoms, and decreased lesions in the mouse lungs. These data suggest that synthetic polyvalent inhibitors of virus attachment can be used for prevention and treatment of influenza.

  7. 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 ...

  8. 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 ...

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Overexpression of the influenza virus polymerase can titrate out inhibition by the murine Mx1 protein.

    PubMed

    Huang, T; Pavlovic, J; Staeheli, P; Krystal, M

    1992-07-01

    The murine Mx1 protein is an interferon-inducible protein which confers selective resistance to influenza virus infection both in vitro and in vivo. The precise mechanism by which the murine Mx1 specifically inhibits replication of influenza virus is not known. Previously, sensitive replication systems for influenza virus ribonucleoprotein, in which a synthetic influenza virus-like ribonucleoprotein is replicated and transcribed by influenza virus proteins provided in trans, have been developed. With these systems, the antiviral activity of the murine Mx1 protein was examined. It was found that continued expression of influenza polymerase polypeptides via vaccinia virus vectors can titrate out the inhibitory action of the murine Mx1 protein. This titration of inhibitory activity also occurs when the viral PB2 protein alone is overexpressed, suggesting that an antiviral target for the murine Mx1 polypeptide is the viral PB2 protein.

  14. 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

  15. 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...

  16. 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

  17. Avian influenza and Newcastle disease viruses from northern pintail in Japan: isolation, characterization and inter-annual comparisons during 2006-2008.

    PubMed

    Jahangir, Alam; Ruenphet, Sakchai; Ueda, Shuhei; Ueno, Yuichi; Shoham, Dany; Shindo, Junji; Okamura, Masashi; Nakamura, Masayuki; Takehara, Kazuaki

    2009-07-01

    Since wild ducks constitute a vital element in the epizootiology of avian influenza viruses (AIVs) as well as avian paramyxoviruses (APMVs) and play a key role in the ecology and inter-species transmission of these viruses, it is crucial to elucidate the diversity and prevalence of these viruses within these bird populations. This report shows the presence, antigenic diversity, and inter-annual prevalence variations of AIVs in apparently healthy northern pintail (Anas acta) wintering in Japan. We also provide evidence that this host carries APMV-1: Newcastle disease virus (NDV) and other haemagglutinating viruses. Composite samples (n=2381) of fresh fecal materials were collected from northern pintail during November 2007-March 2008 at different locations of Tohoku district, main Island, Japan. We isolated 47 haemagglutinating viruses, out of which 25 were identified as AIVs, representing 9 combinations of 5 different haemagglutinin (HA) and 6 neuraminidase (NA) subtypes. Both H5 and H7 subtypes were identified and found to be low pathogenic. A further 11 viruses were grouped into APMV-1 (NDV). The rest of the viruses (n=11) remained to be identified. Some of the HA subtypes and NA subtypes detected during the first season reoccurred in the second season, as well as some of their combinations; yet, several new subtypes and combinations appeared during the second season. These findings indicate that different subtypes of AIVs, NDV and other haemagglutinating viruses circulate subclinically in the pintail populations sampled. Pintails should be regarded, potentially, as important spreaders of AIVs and NDVs, particularly due to their extensively ramified flyways, which include various inter-continental routes.

  18. Surveillance and Analysis of Avian Influenza Viruses, Australia

    PubMed Central

    Warner, Simone; Tracey, John P.; Arzey, K. Edla; Selleck, Paul; O’Riley, Kim; Beckett, Emma L.; Bunn, Chris; Kirkland, Peter D.; Vijaykrishna, Dhanasekaran; Olsen, Bjorn; Hurt, Aeron C.

    2010-01-01

    We investigated carriage of avian influenza viruses by wild birds in Australia, 2005–2008, to assess the risks to poultry industries and human health. We collected 21,858 (7,357 cloacal, 14,501 fecal) samples and detected 300 viruses, representing a detection rate of ≈1.4%. Rates were highest in autumn (March–May) and differed substantially between bird types, areas, and years. We typed 107 avian influenza viruses and identified 19 H5, 8 H7, and 16 H9 (40% of typed viruses). All were of low pathogenicity. These viruses formed clearly different phylogenetic clades to lineages from Eurasia or North America, suggesting the potential existence of Australian lineages. H7 viruses were similar to highly pathogenic H7 strains that caused outbreaks in poultry in Australia. Several periods of increased detection rates (numbers or subtypes of viruses) were identified. This study demonstrates the need for ongoing surveillance to detect emerging pathogenic strains and facilitate prevention of outbreaks. PMID:21122219

  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.

  20. 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

  1. Serological evidence of avian influenza virus and canine influenza virus infections among stray cats in live poultry markets, China.

    PubMed

    Zhou, Han; He, Shu-yi; Sun, Lingshuang; He, Huamei; Ji, Fangxiao; Sun, Yao; Jia, Kun; Ning, Zhangyong; Wang, Heng; Yuan, Liguo; Zhou, Pei; Zhang, Guihong; Li, Shoujun

    2015-02-25

    From January 2010 to January 2012, we collected sera samples from 700 stray cats living in close proximity to poultry farms or poultry markets in 4 provinces in China. A number of cats had evidence of avian and canine influenza virus infection: avian H9N2 [24 by HI ≥1:20 and 16 by microneutralization (MN) assay ≥1:80]; avian H5N1 (9 by HI ≥1:20 and 3 by MN assay ≥1:80) and canine H3N2 (32 by HI ≥1:20 and 18 by MN ≥1:80). Bivariate analyses revealed that cats sampled near live poultry markets and cats with influenza-like-illness were at increased risk of having elevated antibody titers by HI against avian H9N2, avian H5N1, or canine H3N2 viruses. Hence, cats may play a very important role in the ecology of novel influenza viruses and periodic epidemiological surveillance for novel influenza infections among stray cats could serve as an early warning system for human threats.

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

    PubMed

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

    2015-01-01

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

  3. 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

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

    PubMed

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

    2015-01-01

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

  5. 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.

  6. Influenza virus neuraminidase contributes to the dextran sulfate-dependent suppressive replication of some influenza A virus strains.

    PubMed

    Yamada, Hiroshi; Moriishi, Eiko; Haredy, Ahmad M; Takenaka, Nobuyuki; Mori, Yasuko; Yamanishi, Koichi; Okamoto, Shigefumi

    2012-12-01

    Dextran sulfate (DS), a negatively charged, sulfated polysaccharide, suppresses the replication of an influenza A virus strain, and this suppression is associated with inhibition of the hemagglutinin (HA)-dependent fusion activity. However, it remains unknown whether the replication of all or just some influenza A virus strains is suppressed by DS, or whether HA is the only target for the replication suppression. In the present study, we found that DS inhibited the replication of some, but not all influenza A virus strains. The suppression in the DS-sensitive strains was dose-dependent and neutralized by diethylaminoethyl-dextran (DD), which has a positive charge. The suppression by DS was observed not only at the initial stage of viral infection, which includes viral attachment and entry, but also at the late stage, which includes virus assembly and release from infected cells. Electron microscopy revealed that the DS induced viral aggregation at the cell surface. The neuraminidase (NA) activity of the strains whose viral replication was inhibited at the late stage was also more suppressed by DS than that of the strains whose replication was not inhibited, and this inhibition of NA activity was also neutralized by adding positively charged DD. Furthermore, we found that replacing the NA gene of a strain in which viral replication was inhibited by DS at the late stage with the NA gene from a strain in which viral replication was not inhibited, eliminated the DS-dependent suppression. These results suggest that the influenza virus NA contributes to the DS-suppressible virus release from infected cells at the late stage, and the suppression may involve the inhibition of NA activity by DS's negative charge.

  7. Ligand recognition by influenza virus. The binding of bivalent sialosides.

    PubMed

    Glick, G D; Toogood, P L; Wiley, D C; Skehel, J J; Knowles, J R

    1991-12-15

    Infection by influenza virus is initiated by a cellular adhesion event that is mediated by the viral protein, hemagglutinin, which is exposed on the surface of the virion. Hemagglutinin recognizes and binds to cell surface sialic acid residues. Although each individual ligand binding interaction is weak, the high affinity of influenza virus for cells that bear sialic acid residues is thought to result from a multivalent attachment process involving many similar recognition events. To evaluate such binding we have synthesized three series of compounds, each containing two sialic acid residues separated by spacers of different length, and have tested them as ligands for influenza hemagglutinin. No increased binding to the bromelain-released hemagglutinin ectodomain was seen for any of the bivalent compounds as determined by 1H NMR titration. In contrast, however, a spacer length between sialic acid residues of approximately 55 A sharply increases the binding of these bidentate species to whole virus as determined by hemagglutination inhibition assays. The most effective compound containing glycines in the linking chain displayed 100-fold increased affinity for whole virus over the paradigm monovalent ligand, Neu5Ac alpha 2Me.

  8. Nationwide Distribution of Bovine Influenza D Virus Infection in Japan

    PubMed Central

    Horimoto, Taisuke; Hiono, Takahiro; Mekata, Hirohisa; Odagiri, Tomoha; Lei, Zhihao; Kobayashi, Tomoya; Norimine, Junzo; Inoshima, Yasuo; Hikono, Hirokazu; Murakami, Kenji; Sato, Reiichiro; Murakami, Hironobu; Sakaguchi, Masahiro; Ishii, Kazunori; Ando, Takaaki; Otomaru, Kounosuke; Ozawa, Makoto; Sakoda, Yoshihiro; Murakami, Shin

    2016-01-01

    Cattle are major reservoirs of the provisionally named influenza D virus, which is potentially involved in the bovine respiratory disease complex. Here, we conducted a serological survey for the influenza D virus in Japan, using archived bovine serum samples collected during 2010–2016 from several herds of apparently healthy cattle in various regions of the country. We found sero-positive cattle across all years and in all the prefectural regions tested, with a total positivity rate of 30.5%, although the positivity rates varied among regions (13.5–50.0%). There was no significant difference in positivity rates for Holstein and Japanese Black cattle. Positivity rates tended to increase with cattle age. The herds were clearly divided into two groups: those with a high positive rate and those with a low (or no) positive rate, indicating that horizontal transmission of the virus occurs readily within a herd. These data demonstrate that bovine influenza D viruses have been in circulation for at least 5 years countrywide, emphasizing its ubiquitous distribution in the cattle population of Japan. PMID:27682422

  9. 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

  10. 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

  11. Efficient influenza B virus propagation due to deficient interferon-induced antiviral activity in MDCK cells.

    PubMed

    Frensing, Timo; Seitz, Claudius; Heynisch, Bjoern; Patzina, Corinna; Kochs, Georg; Reichl, Udo

    2011-09-22

    Influenza B virus infections are mainly restricted to humans, which is partially caused by the inability of influenza B virus NS1 protein to counteract the innate immune response of other species. However, for cell culture-based influenza vaccine production non-human cells, such as Madin-Darby canine kidney (MDCK) cells, are commonly used. Therefore, the impact of cellular pathogen defence mechanisms on influenza B virus propagation in MDCK cells was analysed in this study. Activation of the cellular antiviral defence by interferon stimulation slowed down influenza B virus replication at early time points but after 48h the same virus titres were reached in stimulated and control cells. Furthermore, suppression of the antiviral host defence by transient expression of a viral antagonist, the rabies virus phosphoprotein, could not increase influenza B virus replication. Finally, canine Myxovirus resistance (Mx) proteins showed no antiviral activity in an influenza B virus-specific minireplicon assay in contrast to the murine Mx1 protein. Taken together, these results indicate that an insufficient antiviral defence in MDCK cells promotes efficient influenza B virus replication favouring the use of MDCK cells in influenza vaccine production.

  12. A highly sensitive europium nanoparticle-based immunoassay for detection of influenza A/B virus antigen in clinical specimens.

    PubMed

    Zhang, Panhe; Vemula, Sai Vikram; Zhao, Jiangqin; Du, Bingchen; Mohan, Haleyurgirisetty; Liu, Jikun; El Mubarak, Haja Sittana; Landry, Marie L; Hewlett, Indira

    2014-12-01

    We report the development of a novel europium nanoparticle-based immunoassay (ENIA) for rapid detection of influenza A and influenza B viruses. The ENIA demonstrated sensitivities of 90.7% (147/162) for influenza A viruses and 81.80% (9/11) for influenza B viruses compared to those for an in-house reverse transcription (RT)-PCR assay in testing of influenza-positive clinical samples.

  13. 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

  14. CT findings in viral lower respiratory tract infections caused by parainfluenza virus, influenza virus and respiratory syncytial virus.

    PubMed

    Kim, Min-Chul; Kim, Mi Young; Lee, Hyun Joo; Lee, Sang-Oh; Choi, Sang-Ho; Kim, Yang Soo; Woo, Jun Hee; Kim, Sung-Han

    2016-06-01

    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

  15. [Influenza].

    PubMed

    Drescher, H J

    1983-01-01

    Influenza is the last great uncontrolled plague of mankind. Pandemics and epidemics occur at regular time intervals. The influenza viruses are divided into the types A, B and C and show unique variability of their surface antigens (hemagglutinin and neuraminidase). Influenza viruses of type A show the largest degree of antigenic variation which, in turn, resulted in the definition of a number of subtypes, each comprising many strains. By comparison, influenza viruses of types B and C exhibit much less variation of their surface antigens. As a consequence, no subtypes but many different strains have been recognized. The degree of antigenic variation correlates with the epidemiologic significance of the virus types, type A being the most and type C the least important. Two different kinds of antigenic variation have been recognized: In the case of minor variation of one or both surface antigens, the term "antigenic drift" is employed. Antigenic drift occurs with all three types of virus, it is caused by point mutations which increase the chance of survival of mutants in the diseased host. In addition, influenza A viruses show sudden and complete changes of their surface antigens in regular time intervals, resulting in the appearance of new subtypes. This event is called "antigenic shift". The mechanisms responsible for antigenic shift are poorly understood, only. In addition to the recycling of preceding subtypes, reassortment resulting from double infection of cells with strains of human and animal origin are considered possible explanations. By use of modern DNA recombinant technology, the base sequences of a series of virus genes and, as a consequence, the amino acid sequence of the corresponding antigens have been determined. By means of monoclonal antibodies, the antigenic structure of many influenza antigens has been further elucidated. It can be expected that further research on the molecular basis of antigenic variation could finally result in an

  16. [Improved method of determining the infectivity of the influenza virus].

    PubMed

    Zhirnov, O P; Ovcharenko, A V; Bukrinskaia, A G

    1981-01-01

    The infectious activity of influenza A virus preparations with different ratios of unsplit (HA) and split (HA1 + HA2) hemagglutinin was studied. For this purpose the virus was cultivated in chick embryos (the virus with split hemagglutinin), chick fibroblast culture (unsplit hemagglutinin) and in chick fibroblast culture to the medium of which chick embryo allantoic fluid was added (partially split hemagglutinin). Proteins were analysed by polyacrylamide gel electrophoresis followed by the scanning of the gels. An improved plaque method in cell cultures under the agar overlay was used to assay the infectious activity of the virus preparations. This method gave more accurate determinations of the infectious titre of the preparations tested. The routine titration method gave higher infectious titres of the preparations particularly for the virus with unsplit hemagglutinin. Employing the new method, a ratio of infectious and physical particles in preparations with different HA/HA1 + HA2 contents was determined and the productive activity of cells of the chorioallantoic membrane in chick embryos and chick fibroblast cell cultures infected with influenza virus was evaluated.

  17. Epidemiologic implications of changes in the influenza virus genome.

    PubMed

    Kendal, A P

    1987-06-19

    Among the molecular maneuvers that enable the influenza virus to survive are antigenic variation and functional alterations. Two kinds of minor antigenic variations, producing new strains within type A virus subtypes, have been discovered: antigenic drift, in which the amino acid sequences of the antigens are changed; and antigenic camouflage, in which the antigens are glycosylated. Both kinds of variation are caused by mutations in the viral genome. These mutations produce slightly changed antigens, which many existing antibodies cannot recognize. Major antigenic variations (so-called antigenic shift) are produced by gene reassortment. Two subtypes, coinfecting a host, can reassort their eight ribonucleoprotein gene segments into as many as 256 different combinations. Such recombinations can produce new viruses with the potential for transmission in humans, but whose surface antigens are completely unmatched by antibodies in the population, permitting a pandemic to occur. Functional changes, caused by mutations, alter the interactions between the virus and the host, including virus binding to host receptor sites and fusion of viral and host membranes. All these mechanisms allow the influenza virus to survive in humans, probably perpetually.

  18. 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.

  19. Avian influenza virus infection risk in humans with chronic diseases.

    PubMed

    Zhong, Yaogang; Qin, Yannan; Yu, Hanjie; Yu, Jingmin; Wu, Haoxiang; Chen, Lin; Zhang, Peixin; Wang, Xiurong; Jia, Zhansheng; Guo, Yonghong; Zhang, Hua; Shan, Junjie; Wang, Yuxia; Xie, Hailong; Li, Xiaojie; Li, Zheng

    2015-01-01

    Saliva proteins may protect older people from influenza, however, it is often noted that hospitalizations and deaths after an influenza infection mainly occur in the elderly population living with chronic diseases, such as diabetes and cancer. Our objective was to investigate the expression level of the terminal α2-3- and α2-6-linked sialic acids in human saliva from type 2 diabetes mellitus (T2DM), liver disease and gastric cancer (GC) patients and assess the binding activity of these linked sialic acids against influenza A viruses (IAV). We observed that the expression level of the terminal α2-3-linked sialic acids of elderly individuals with T2DM and liver disease were down-regulated significantly, and the terminal α2-6 linked sialic acids were up-regulated slightly or had no significant alteration. However, in the saliva of patients with GC, neither sialic acid was significantly altered. These findings may reveal that elderly individuals with chronic diseases, such as diabetes and liver disease, might be more susceptible to the avian influenza virus due to the decreased expression of terminal α2-3-linked sialic acids in their saliva.

  20. 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

  1. 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

  2. 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

  3. ANTIGENIC AND GENETIC CHARACTERIZATION OF INFLUENZA B VIRUSES IN 2012 FROM SLUMS, DHAKA, BANGLADESH.

    PubMed

    Islam, Mohammad Ariful; Sultana, Nazneen; Ahmed, Firoz; Rahman, M Majibur; Rahman, Sabita Rezwana

    2015-07-01

    Nasal and throat swab samples were collected from 400 subjects with influenza-like illness during June to September, 2012 from two heavily crowded slums, Rayerbazar and Hazaribagh, situated southeast of Dhaka, Bangladesh. Forty-one samples were positive for influenza B virus using quantitative RT-PCR, but no influenza A virus was detected. Antigenic characterization revealed that the influenza B viruses were of Yamagata and Victoria lineages, which was confirmed from genetic analysis of hemagglutinin (HA) and neuraminidase (NA) genes. Co-circulation of influenza B viruses of both Yamagata and Victoria lineages in the slums of Dhaka indicates that introduction of a tetravalent vaccine formulation that includes both of these influenza B virus lineages would be more effective in this population.

  4. Insertion of a GFP reporter gene in influenza virus.

    PubMed

    Perez, Jasmine T; García-Sastre, Adolfo; Manicassamy, Balaji

    2013-01-01

    The incorporation of a fluorescent reporter gene into a replication-competent influenza A virus (IAV) has made it possible to trace IAV infection in vivo. This protocol describes the process of inserting a green fluorescent protein (GFP) reporter into the IAV genome using the established reverse genetics system. The strategy begins with the reorganization of segment eight of the IAV genome, during which the open reading frames of nonstructural protein 1 (NS1) and the nuclear export protein (NEP) are separated to allow for GFP fusion to the NS1 protein. The NS1, GFP, and NEP open reading frames (ORF) are then cloned into the IAV rescue system backbone. Upon construction of the GFP-encoding segment eight rescue plasmid, recombinant NS1-GFP influenza virus can be rescued via co-transfection with the remaining seven rescue plasmids. The generated NS1-GFP IAV can subsequently be used to visualize infected cells, both in vitro and in vivo.

  5. Comparison of traditional intranasal and aerosol inhalation inoculation of mice with influenza A viruses.

    PubMed

    Belser, Jessica A; Gustin, Kortney M; Katz, Jacqueline M; Maines, Taronna R; Tumpey, Terrence M

    2015-07-01

    Intranasal instillation of virus in a liquid suspension (IN) is the most frequently employed method to inoculate small mammalian models with influenza virus, but does not reflect a natural route of exposure. In contrast, inoculation via aerosol inhalation (AR) more closely resembles human exposure to influenza virus. Studies in mice have yielded conflicting results regarding virulence induced by virus inoculated by these routes, and have not controlled for potential strain-specific differences, or examined contemporary influenza viruses and avian viruses with pandemic potential. We used a whole-body AR inoculation method to compare infectivity and disease progression of a highly pathogenic H5N1, a low pathogenic H7N9, and a 2009 H1N1 virus with traditional IN inoculation in the mouse model. Generally comparable levels of morbidity and mortality were observed with all viruses examined using either inoculation route, indicating that both IN and AR delivery are appropriate for murine studies investigating influenza virus pathogenicity.

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

    PubMed

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

    2013-01-01

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

  7. Influenza B virus-specific CD8+ T-lymphocytes strongly cross-react with viruses of the opposing influenza B lineage.

    PubMed

    van de Sandt, Carolien E; Dou, YingYing; Vogelzang-van Trierum, Stella E; Westgeest, Kim B; Pronk, Mark R; Osterhaus, Albert D M E; Fouchier, Ron A M; Rimmelzwaan, Guus F; Hillaire, Marine L B

    2015-08-01

    Influenza B viruses fall in two antigenically distinct lineages (B/Victoria/2/1987 and B/Yamagata/16/1988 lineage) that co-circulate with influenza A viruses of the H3N2 and H1N1 subtypes during seasonal epidemics. Infections with influenza B viruses contribute considerably to morbidity and mortality in the human population. Influenza B virus neutralizing antibodies, elicited by natural infections or vaccination, poorly cross-react with viruses of the opposing influenza B lineage. Therefore, there is an increased interest in identifying other correlates of protection which could aid the development of broadly protective vaccines. blast analysis revealed high sequence identity of all viral proteins. With two online epitope prediction algorithms, putative conserved epitopes relevant for study subjects used in the present study were predicted. The cross-reactivity of influenza B virus-specific polyclonal CD8+ cytotoxic T-lymphocyte (CTL) populations obtained from HLA-typed healthy study subjects, with intra-lineage drift variants and viruses of the opposing lineage, was determined by assessing their in vitro IFN-γ response and lytic activity. Here, we show for the first time, to the best of our knowledge, that CTLs directed to viruses of the B/Victoria/2/1987 lineage cross-react with viruses of the B/Yamagata/16/1988 lineage and vice versa.

  8. 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 ...

  9. [Contribution to the antigenic study of influenza viruses in animals. I.--Neuraminidase of the equine influenza viruses (author's transl)].

    PubMed

    Fontaine, M; Aymard-Henry, M

    1975-01-01

    From the Revised Nomenclature of WHO, the fowl influenza virus A/Duck/Ukraine/63 (Hav7 Neq2) has the same neuraminidase as the equine virus A/equi 2/Miami/63 (Heq2 Neq2); the A/Chicken Germany "N"/49 virus has the same neuraminidase as the equine virus A/equi 1/Prague/56. A comparative study of the antigenic specificities confirms that the Neq2 neuraminidases are closely connected, whatever their animal origin, and that the fowl strain Hav7 Neq2 can be used for the titration of anti Neq2 antibodies in the serums of animals immunized with the equine virus Heq2 Neq2. The Neqi neuraminidases of various animal origins are connected, but the neuraminidase of the fowl strain Hav2 Neqi is slightly inhibited by the anti Neq1 antibodies of animals immunized with the Heq1 Neq1 virus: to titrate the anti Neq1 antibodies of equine origin, the H72 Neq1 recombinant should therefore be used. The antigenic characterization of the different equine influenza strains isolated since 1967 by the study of their neuraminidase has been completed: The various neuraminidases, like the hemagglutinins of the various strains belonging to the sub-type A equi2 are closely connected; a minor antigenic variation, concerning the two surface antigens, seems to exist between the strain A equi 1/Prague/56 and the strain of the same subtype isolated in 1973.

  10. 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

  11. H5N1 influenza viruses: facts, not fear.

    PubMed

    Palese, Peter; Wang, Taia T

    2012-02-14

    The ongoing controversy over publication of two studies involving the transmission in ferrets of H5N1 (H5) subtype influenza viruses and the recommendations of the National Science Advisory Board for Biosecurity to redact key details in the manuscripts call for an examination of relevant scientific facts. In addition, there are calls in the media to destroy the viruses, curtail future research in this area, and protect the public from such "frightening" research efforts. Fear needs to be put to rest with solid science and not speculation.

  12. 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

  13. 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

  14. Calorimetric detection of influenza virus induced membrane fusion.

    PubMed

    Nebel, S; Bartoldus, I; Stegmann, T

    1995-05-01

    Membrane fusion induced by the hemagglutinin glycoprotein of influenza virus has been extensively characterized, but the mechanism whereby the protein achieves the merger of the viral and target membrane lipids remains enigmatic. Various lipid intermediate structures have been proposed, and the energies required for their formation predicted. Here, we have analyzed the enthalpies of fusion of influenza with liposomes by titration calorimetry. If a small sample of virus in a weak neutral pH buffer was added to an excess of liposomes at low pH, a two-component reaction was seen, composed of an exothermic reaction and a slower endothermic reaction. The exothermic reaction was the result of acid-base reactions between the neutral pH virus sample and low pH buffer and low-pH-induced changes in the virus. The endothermic reaction was not observed in the absence of liposomes and much reduced if acid-inactivated virus, which had lost its fusion but not its binding activity, was added to liposomes. The endothermic reaction was more temperature dependent than the exothermic reaction; its pH dependence corresponded with that of fusion and its enthalpy was higher if fusion was more extensive. These data indicate that most of the endothermic reaction was due to membrane fusion. The experimentally determined enthalpy of fusion, 0.6-0.7 kcal per mol of viral phospholipids, is much higher than expected on the basis of current theories about the formation of lipid intermediates during membrane fusion.

  15. A quantitative comet infection assay for influenza virus.

    PubMed

    Lindsay, Stephen M; Timm, Andrea; Yin, John

    2012-02-01

    The virus comet assay is a cell-based virulence assay used to evaluate an antiviral drug or antibody against a target virus. The comet assay differs from the plaque assay in allowing spontaneous flows in 6-well plates to spread virus. When implemented quantitatively the comet assay has been shown to have an order-of-magnitude greater sensitivity to antivirals than the plaque assay. In this study, a quantitative comet assay for influenza virus is demonstrated, and is shown to have a 13-fold increase in sensitivity to ribavirin. AX4 cells (MDCK cells with increased surface concentration of α2-6 sialic acid, the influenza virus receptor) have reduced the comet size variability relative to MDCK cells, making them a better host cell for use in this assay. Because of enhanced antiviral sensitivity in flow-based assays, less drug is required, which could lead to lower reagent costs, reduced cytotoxicity, and fewer false-negative drug screen results. The comet assay also serves as a readout of flow conditions in the well. Observations from comets formed at varying humidity levels indicate a role for evaporation in the mechanism of spontaneous fluid flow in wells.

  16. The epidemiology and spread of drug resistant human influenza viruses.

    PubMed

    Hurt, Aeron C

    2014-10-01

    Significant changes in the circulation of antiviral-resistant influenza viruses have occurred over the last decade. The emergence and continued circulation of adamantane-resistant A(H3N2) and A(H1N1)pdm09 viruses mean that the adamantanes are no longer recommended for use. Resistance to the newer class of drugs, the neuraminidase inhibitors, is typically associated with poorer viral replication and transmission. But 'permissive' mutations, that compensated for impairment of viral function in A(H1N1) viruses during 2007/2008, enabled them to acquire the H275Y NA resistance mutation without fitness loss, resulting in their rapid global spread. Permissive mutations now appear to be present in A(H1N1)pdm09 viruses thereby increasing the risk that oseltamivir-resistant A(H1N1)pdm09 viruses may also spread globally, a concerning scenario given that oseltamivir is the most widely used influenza antiviral.

  17. Impact of influenza A(H1N1)pdm09 virus on circulation dynamics of seasonal influenza strains in Kenya.

    PubMed

    Majanja, Janet; Njoroge, Rose N; Achilla, Rachel; Wurapa, Eyako K; Wadegu, Meshack; Mukunzi, Silvanos; Mwangi, Josephat; Njiri, James; Gachara, George; Bulimo, Wallace

    2013-05-01

    We describe virus variations from patients with influenza-like illness before and after the appearance of influenza A(H1N1)pdm09 in Kenya during January 2008-July 2011. A total of 11,592 nasopharyngeal swabs were collected from consenting patients. Seasonal influenza B, A/H1N1, A/H3N2, A/H5N1, and influenza A(H1N1)pdm09 viruses were detected by real-time reverse transcription-polymerase chain reaction. Of patients enrolled, 2073 (17.9%) had influenza. A total of 1,524 (73.4%) of 2,073 samples were positive for influenza A virus and 549 (26.6%) were positive for influenza B virus. Influenza B virus predominated in 2008 and seasonal A(H1N1) virus predominated in the first half of 2009. Influenza A(H1N1)pdm09 virus predominated in the second half of 2009. Influenza A/H3N2 virus predominated in 2010, and co-circulation of influenza A(H1N1)pdm09 virus and influenza B virus predominated the first half of 2011. The reduction and displacement of seasonal A(H1N1) virus was the most obvious effect of the arrival of influenza A(H1N1)pdm09 virus. The decision of the World Health Organization to replace seasonal A(H1N1) virus with the pandemic virus strain for the southern hemisphere vaccine was appropriate for Kenya.

  18. 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

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

    PubMed

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

    2013-06-01

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

  20. Rapid production of a H₉ N₂ influenza vaccine from MDCK cells for protecting chicken against influenza virus infection.

    PubMed

    Ren, Zhenghua; Lu, Zhongzheng; Wang, Lei; Huo, Zeren; Cui, Jianhua; Zheng, Tingting; Dai, Qing; Chen, Cuiling; Qin, Mengying; Chen, Meihua; Yang, Rirong

    2015-04-01

    H9N2 subtype avian influenza viruses are widespread in domestic poultry, and vaccination remains the most effective way to protect the chicken population from avian influenza pandemics. Currently, egg-based H9N2 influenza vaccine production has several disadvantages and mammalian MDCK cells are being investigated as candidates for influenza vaccine production. However, little research has been conducted on low pathogenic avian influenza viruses (LPAIV) such as H9N2 replicating in mammalian cells using microcarrier beads in a bioreactor. In this study, we present a systematic analysis of a safe H9N2 influenza vaccine derived from MDCK cells for protecting chickens against influenza virus infection. In 2008, we isolated two novel H9N2 influenza viruses from chickens raised in southern China, and these H9N2 viruses were adapted to MDCK cells. The H9N2 virus was produced in MDCK cells in a scalable bioreactor, purified, inactivated, and investigated for use as a vaccine. The MDCK-derived H9N2 vaccine was able to induce high titers of neutralizing antibodies in chickens of different ages. Histopathological examination, direct immunofluorescence, HI assay, CD4(+)/CD8(+) ratio test, and cytokine evaluation indicated that the MDCK-derived H9N2 vaccine evoked a rapid and effective immune response to protect chickens from influenza infection. High titers of H9N2-specific antibodies were maintained in chickens for 5 months, and the MDCK-derived H9N2 vaccine had no effects on chicken growth. The use of MDCK cells in bioreactors for LPAIV vaccine production is an attractive option to prevent outbreaks of LPAIV in poultry.

  1. 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

  2. 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

  3. Protection and virus shedding of falcons vaccinated against highly pathogenic avian influenza A virus (H5N1).

    PubMed

    Lierz, Michael; Hafez, Hafez M; Klopfleisch, Robert; Lüschow, Dörte; Prusas, Christine; Teifke, Jens P; Rudolf, Miriam; Grund, Christian; Kalthoff, Donata; Mettenleiter, Thomas; Beer, Martin; Hardert, Timm

    2007-11-01

    Because fatal infections with highly pathogenic avian influenza A (HPAI) virus subtype H5N1 have been reported in birds of prey, we sought to determine detailed information about the birds' susceptibility and protection after vaccination. Ten falcons vaccinated with an inactivated influenza virus (H5N2) vaccine seroconverted. We then challenged 5 vaccinated and 5 nonvaccinated falcons with HPAI (H5N1). All vaccinated birds survived; all unvaccinated birds died within 5 days. For the nonvaccinated birds, histopathologic examination showed tissue degeneration and necrosis, immunohistochemical techniques showed influenza virus antigen in affected tissues, and these birds shed high levels of infectious virus from the oropharynx and cloaca. Vaccinated birds showed no influenza virus antigen in tissues and shed virus at lower titers from the oropharynx only. Vaccination could protect these valuable birds and, through reduced virus shedding, reduce risk for transmission to other avian species and humans.

  4. Avian influenza h6 viruses productively infect and cause illness in mice and ferrets.

    PubMed

    Gillim-Ross, Laura; Santos, Celia; Chen, Zhongying; Aspelund, Amy; Yang, Chin-Fen; Ye, Dan; Jin, Hong; Kemble, George; Subbarao, Kanta

    2008-11-01

    Influenza pandemic preparedness has focused on influenza virus H5 and H7 subtypes. However, it is not possible to predict with certainty which subtype of avian influenza virus will cause the next pandemic, and it is prudent to include other avian influenza virus subtypes in pandemic preparedness efforts. An H6 influenza virus was identified as a potential progenitor of the H5N1 viruses that emerged in Hong Kong in 1997. This virus continues to circulate in the bird population in Asia, and other H6 viruses are prevalent in birds in North America and Asia. The high rate of reassortment observed in influenza viruses and the prevalence of H6 viruses in birds suggest that this subtype may pose a pandemic risk. Very little is known about the replicative capacity, immunogenicity, and correlates of protective immunity for low-pathogenicity H6 influenza viruses in mammals. We evaluated the antigenic and genetic relatedness of 14 H6 influenza viruses and their abilities to replicate and induce a cross-reactive immune response in two animal models: mice and ferrets. The different H6 viruses replicated to different levels in the respiratory tracts of mice and ferrets, causing varied degrees of morbidity and mortality in these two models. H6 virus infection induced similar patterns of neutralizing antibody responses in mice and ferrets; however, species-specific differences in the cross-reactivity of the antibody responses were observed. Overall, cross-reactivity of neutralizing antibodies in H6 virus-infected mice did not correlate well with protection against heterologous wild-type H6 viruses. However, we have identified an H6 virus that induces protective immunity against viruses in the North American and Eurasian lineages.

  5. First reported incursion of highly pathogenic notifiable avian influenza A H5N1 viruses from clade 2.3.2 into European poultry.

    PubMed

    Reid, S M; Shell, W M; Barboi, G; Onita, I; Turcitu, M; Cioranu, R; Marinova-Petkova, A; Goujgoulova, G; Webby, R J; Webster, R G; Russell, C; Slomka, M J; Hanna, A; Banks, J; Alton, B; Barrass, L; Irvine, R M; Brown, I H

    2011-02-01

    This study reports the first incursion into European poultry of H5N1 highly pathogenic notifiable avian influenza A (HPNAI) viruses from clade 2.3.2 that affected domestic poultry and wild birds in Romania and Bulgaria, respectively. Previous occurrences in Europe of HPNAI H5N1 in these avian populations have involved exclusively viruses from clade 2.2. This represents the most westerly spread of clade 2.3.2 viruses, which have shown an apparently expanding range of geographical dispersal since mid-2009 following confirmation of infections in wild waterfowl species in Mongolia and Eastern Russia. During March 2010, AI infection was suspected at post-mortem examination of two hens from two backyard flocks in Tulcea Country, Romania. HPNAI of H5N1 subtype was confirmed by reverse transcription polymerase chain reaction (RT-PCR). A second outbreak was confirmed 2 weeks later by RT-PCR, affecting all hens from another flock located 55 km east of the first cluster. On the same day, an H5N1 HPNAI virus was detected from a pooled tissue sample collected from a dead Common Buzzard found on the Black Sea coast in Bulgaria. Detailed genetic characterization of the haemagglutinin gene revealed the cleavage site of the isolates to be consistent with viruses of high pathogenicity belonging to clade 2.3.2 of the contemporary Eurasian H5N1 lineage. Viruses from a clade other than 2.2 have apparently spread to wild birds, with potential maintenance and spread through such populations. Whilst the scale of threat posed by the apparent westward spread of the clade 2.3.2 viruses remains uncertain, ongoing vigilance for clinical signs of disease as part of existing passive surveillance frameworks for AI, and the prompt reporting of suspect cases in poultry is advised.

  6. Molecular Epidemiology and Phylogenetic Analyses of Influenza B Virus in Thailand during 2010 to 2014

    PubMed Central

    Tewawong, Nipaporn; Suwannakarn, Kamol; Prachayangprecha, Slinporn; Korkong, Sumeth; Vichiwattana, Preeyaporn; Vongpunsawad, Sompong; Poovorawan, Yong

    2015-01-01

    Influenza B virus remains a major contributor to the seasonal influenza outbreak and its prevalence has increased worldwide. We investigated the epidemiology and analyzed the full genome sequences of influenza B virus strains in Thailand between 2010 and 2014. Samples from the upper respiratory tract were collected from patients diagnosed with influenza like-illness. All samples were screened for influenza A/B viruses by one-step multiplex real-time RT-PCR. The whole genome of 53 influenza B isolates were amplified, sequenced, and analyzed. From 14,418 respiratory samples collected during 2010 to 2014, a total of 3,050 tested positive for influenza virus. Approximately 3.27% (471/14,418) were influenza B virus samples. Fifty three isolates of influenza B virus were randomly chosen for detailed whole genome analysis. Phylogenetic analysis of the HA gene showed clusters in Victoria clades 1A, 1B, 3, 5 and Yamagata clades 2 and 3. Both B/Victoria and B/Yamagata lineages were found to co-circulate during this time. The NA sequences of all isolates belonged to lineage II and consisted of viruses from both HA Victoria and Yamagata lineages, reflecting possible reassortment of the HA and NA genes. No significant changes were seen in the NA protein. The phylogenetic trees generated through the analysis of the PB1 and PB2 genes closely resembled that of the HA gene, while trees generated from the analysis of the PA, NP, and M genes showed similar topology. The NS gene exhibited the pattern of genetic reassortment distinct from those of the PA, NP or M genes. Thus, antigenic drift and genetic reassortment among the influenza B virus strains were observed in the isolates examined. Our findings indicate that the co-circulation of two distinct lineages of influenza B viruses and the limitation of cross-protection of the current vaccine formulation provide support for quadrivalent influenza vaccine in this region. PMID:25602617

  7. Effectiveness of common healthcare disinfectants against H1N1 influenza virus on reusable elastomeric respirators.

    PubMed

    Subhash, Shobha S; Cavaiuolo, Maria; Radonovich, Lewis J; Eagan, Aaron; Lee, Martin L; Campbell, Sheldon; Martinello, Richard A

    2014-07-01

    This study evaluated the efficacy of 3 common hospital disinfectants to inactivate influenza virus on elastomeric respirators. Quaternary ammonium/isopropyl alcohol and bleach detergent wipes eliminated live virus, whereas 70% isopropyl alcohol alone was ineffective.

  8. Role for proteases and HLA-G in the pathogenicity of influenza A viruses.

    PubMed

    Foucault, Marie-Laure; Moules, Vincent; Rosa-Calatrava, Manuel; Riteau, Béatrice

    2011-07-01

    Influenza is one of the most common infectious diseases in humans occurring as seasonal epidemic and sporadic pandemic outbreaks. The ongoing infections of humans with avian H5N1 influenza A viruses (IAV) and the past 2009 pandemic caused by the quadruple human/avian/swine reassortant (H1N1) virus highlights the permanent threat caused by these viruses. This review aims to describe the interaction between the virus and the host, with a particular focus on the role of proteases and HLA-G in the pathogenicity of influenza viruses.

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

    PubMed

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

    2010-11-01

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

  11. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.

    PubMed

    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

    2016-02-19

    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.

  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. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.

    PubMed

    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

  14. 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...

  15. 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

  16. 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

  17. 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

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

    PubMed

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

    2013-01-01

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

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

    PubMed

    Karmacharya, Dibesh; Manandhar, Sulochana; 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.

  20. 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

  1. 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

  2. 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

  3. Adaptation of Pandemic H2N2 Influenza A Viruses in Humans

    PubMed Central

    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.

    2014-01-01

    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

  4. 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.

  5. 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

  6. 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

  7. 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

  8. The surface receptor is a major determinant of the cell tropism of influenza C virus.

    PubMed

    Herrler, G; Klenk, H D

    1987-07-01

    N-Acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) has been shown to be a high-affinity receptor determinant for attachment of influenza C virus to erythrocytes (G. N. Rogers, G. Herrler, J. C. Paulson, and H-D. Klenk, 1986, J. Biol. Chem. 261, 5947-5951). In this report the nature of the cell surface receptor for influenza C virus on tissue culture cells was analyzed. Pretreatment with either neuraminidase or neuraminate 9-O-acetylesterase was found to render LLC-MK2 cells resistant to infection by influenza C virus as evidenced by the failure to detect virus release into the medium by hemagglutination titration. Susceptibility to infection was fully restored after incubation of neuraminidase-treated cells with bovine brain gangliosides known to contain Neu5,9Ac2. These results indicate that (i) Neu5,9Ac2 is the primary receptor determinant required for influenza C virus to attach to tissue culture cells and to initiate infection and (ii) gangliosides containing this type of sialic acid are potential receptors for influenza C virus. Several cell lines which are resistant to infection by this virus were able to release influenza C virus into the medium provided they were incubated with bovine brain gangliosides prior to virus infection. This result indicates that lack of appropriate receptors on the cell surface is a major reason for the restricted cell tropism of influenza C virus.

  9. [Study of biological characteristics of the IVpi-189 virus derived from persistent influenza A virus-infected cell line].

    PubMed

    Liu, Jing; Zhang, Lei-Ying; Na, Li-Xin; Yan, Jian-Zhong; Liu, Bei-Xing

    2011-07-01

    To investigate biological characteristics of the IVpi-189 progeny virus derived from the culture of influenza A virus as a live-attenuated vaccine candidate. Persistent infection of a cultured cell line with influenza A virus (MDCK-IVpi) was established by incubating continuously influenza virus-infected cells at a lower temperature. The infectious progeny virus derived from MDCK-IVpi cells at the 189rd subculture was designated as the IVpi-189 strain of influenza virus. The cytopathic effect induced by IVpi-189 virus was observed under different temperature conditions. The production of infectious progeny virus was examined at 38 and 32 degrees C by plaque titration of cell-associated and released virus. IVpi-189 virus showed cytopathic effect as strong as that of IVwt in infected cell line of MDCK at 32 degrees C. However, when culture temperature was raised to 38 degrees C, the cytopathic effect induced by IVpi-189 virus was delayed and less pronounced. Virus growth in IVpi-189 virus-infected cells at 38 degrees C was significantly reduced as compared with that of IVwt virus, although both viruses yielded nearly equivalent high titers of cell-associated and released virus at 32 degrees C. The reasons of the decreased proliferative ability of IVpi-189 virus at high culture temperature were unrelated with virus inactivation or the release of progeny virus, but associated with the decreased replication of infectious progeny virus in the infected cells. IVpi-189 virus derived from MDCK cells infected persistently with influenza A virus showed biological characteristics as a potential live-attenuated vaccine candidate.

  10. Characterization of the Subunit Structure of the Ribonucleic Acid Genome of Influenza Virus

    PubMed Central

    Lewandowski, L. J.; Content, J.; Leppla, S. H.

    1971-01-01

    Ribonucleic acid extracted from influenza virus was labeled at the 3′ termini with 3H and analyzed by polyacrylamide gel electrophoresis. Influenza virus was found to contain a minimum of seven and possibly as many as 10 polynucleotide chains, most of which appear to terminate at the 3′ end in uridine. PMID:4332140

  11. 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.

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. Kinetics of Coinfection with Influenza A Virus and Streptococcus pneumoniae

    DOE PAGES

    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

  19. 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

  20. 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...

  1. 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...

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

    PubMed

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

    2013-04-12

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

  3. Sublingual administration of bacteria-expressed influenza virus hemagglutinin 1 (HA1) induces protection against infection with 2009 pandemic H1N1 influenza virus.

    PubMed

    Shim, Byoung-Shik; Choi, Jung-Ah; Song, Ho-Hyun; Park, Sung-Moo; Cheon, In Su; Jang, Ji-Eun; Woo, Sun Je; Cho, Chung Hwan; Song, Min-Suk; Kim, Hyemi; Song, Kyung Joo; Lee, Jae Myun; Kim, Suhng Wook; Song, Dae Sub; Choi, Young Ki; Kim, Jae-Ouk; Nguyen, Huan Huu; Kim, Dong Wook; Bahk, Young Yil; Yun, Cheol-Heui; Song, Man Ki

    2013-02-01

    Influenza viruses are respiratory pathogens that continue to pose a significantly high risk of morbidity and mortality of humans worldwide. Vaccination is one of the most effective strategies for minimizing damages by influenza outbreaks. In addition, rapid development and production of efficient vaccine with convenient administration is required in case of influenza pandemic. In this study, we generated recombinant influenza virus hemagglutinin protein 1 (sHA1) of 2009 pandemic influenza virus as a vaccine candidate using a well-established bacterial expression system and administered it into mice via sublingual (s.l.) route. We found that s.l. immunization with the recombinant sHA1 plus cholera toxin (CT) induced mucosal antibodies as well as systemic antibodies including neutralizing Abs and provided complete protection against infection with pandemic influenza virus A/CA/04/09 (H1N1) in mice. Indeed, the protection efficacy was comparable with that induced by intramuscular (i.m.) immunization route utilized as general administration route of influenza vaccine. These results suggest that s.l. vaccination with the recombinant non-glycosylated HA1 protein offers an alternative strategy to control influenza outbreaks including pandemics. PMID:23456722

  4. 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.

  5. 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

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

    PubMed

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

    2002-02-01

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

  7. Strategies to alleviate original antigenic sin responses to influenza viruses

    PubMed Central

    Kim, Jin Hyang; Davis, William G.; Sambhara, Suryaprakash; Jacob, Joshy

    2012-01-01

    Original antigenic sin is a phenomenon wherein sequential exposure to closely related influenza virus variants reduces antibody (Ab) response to novel antigenic determinants in the second strain and, consequently, impairs the development of immune memory. This could pose a risk to the development of immune memory in persons previously infected with or vaccinated against influenza. Here, we explored strategies to overcome original antigenic sin responses in mice sequentially exposed to two closely related hemagglutinin 1 neuraminidase 1 (H1N1) influenza strains A/PR/8/34 and A/FM/1/47. We found that dendritic cell–activating adjuvants [Bordetella pertussis toxin (PT) or CpG ODN or a squalene-based oil-in-water nanoemulsion (NE)], upon administration during the second viral exposure, completely protected mice from a lethal challenge and enhanced neutralizing-Ab titers against the second virus. Interestingly, PT and NE adjuvants when administered during the first immunization even prevented original antigenic sin in subsequent immunization without any adjuvants. As an alternative to using adjuvants, we also found that repeated immunization with the second viral strain relieved the effects of original antigenic sin. Taken together, our studies provide at least three ways of overcoming original antigenic sin. PMID:22869731

  8. 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

  9. 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

  10. Construction high-yield candidate influenza vaccine viruses in Vero cells by reassortment.

    PubMed

    Yu, Wei; Yang, Fan; Yang, Jinghui; Ma, Lei; Cun, Yina; Song, Shaohui; Liao, Guoyang

    2016-11-01

    Usage of influenza vaccine is the best choice measure for preventing and conclusion of influenza virus infection. Although it has been used of chicken embryo to produce influenza vaccine, following with WHO recommended vaccine strain, there were uncontrollable factors and its deficiencies, specially, during an influenza pandemic in the world. The Vero cells are used for vaccine production of a few strains including influenza virus, because of its homology with human, recommended by WHO. However, as known most of the influenza viruses strains could not culture by Vero cells. It was used two high-yield influenza viruses adapted in Vero cells as donor viruses, such as A/Yunnan/1/2005Va (H3N2) and B/Yunnan/2/2005Va (B), to construct high-yield wild influenza virus in Vero cells under antibody selection pressure. After reassortment and passages, it obtained the new Vaccine strains with A/Tianjin/15/2009Va (H1N1), A/Fujian/196/2009Va (H3N2) and B/Chongqing/1384/2010Va (B), which was not only completely keeping their original antigenic (HA and NA), but also grown well in Vero cells with high-yield. All results of gene analysis and HA, HI shown that this reassortment method could be used to find new direction to product the influenza vaccine. J. Med. Virol. 88:1914-1921, 2016. © 2016 Wiley Periodicals, Inc. PMID:27101353

  11. [Comparison of four rapid diagnostic kits using immunochromatography to detect influenza B viruses].

    PubMed

    Hara, Michimaru; Takao, Shinichi; Fukuda, Shinji; Shimazu, Yukie; Kuwayama, Masaru; Miyazaki, Kazuo

    2005-10-01

    We compared the usefulness of 4 rapid influenza diagnostic 1-device kits using immunochromatography, which facilitate type differentiation, i.e. ESPLINE Influenza A&B-N (Fujirebio Corp., Japan: ESPLINE), POCTEM INFLUENZA A/B (Sysmex Corp., Japan: POCTEM), Quick Vue Rapid SP influ (Quidel Corp., U.S.A.: Quick Vue), and Capilia Flu A + B (TAUNS Corp., Japan: Capilia), in 278 children in whom influenza infection was suspected in 2004 and 2005. Nasopharyngeal aspirates were diluted for virus isolation and residual samples were centrifuged. Using the supernatant, we conducted rapid diagnosis testing. Influenza virus AH3 was isolated from 40 children, and influenza B virus from 163. Of the 40 children, the sensitivity and specificity of ESPLINE, POCTEM, Quick Vue, and Capilia were 100%/100%, 95%/100%, 98%/96%, and 98%/96%. In the 163 children, the sensitivity and specificity were 89%/100%, 87%/100%, 88%/97%, and 86%/98%. ESPLINE showed the highest sensitivity and specificity to influenza viruses AH3 and B. All kits were less sensitive to influenza B virus than to influenza A virus, however. The specificity of Quick Vue and Capilia was low; so these kits must be improved.

  12. A rapid method for immunotitration of influenza viruses using flow cytometry.

    PubMed

    Lonsdale, R; Pau, M G; Oerlemans, M; Ophorst, C; Vooys, A; Havenga, M; Goudsmit, J; UytdeHaag, F; Marzio, G

    2003-06-01

    Reliable assays for accurate titration of influenza virus in infectious samples are pivotal to both influenza research and vaccine development. A titration assay adopted commonly for this purpose is the plaque assay on Madin-Darby canine kidney (MDCK) cells, despite it being time and labour consuming. A novel assay is described for titration of influenza viruses based on the detection of intracellular viral nucleoprotein (NP) by fluorescence-activated cell sorting (FACS). By using a panel of viruses of different type, subtype and origin, it is demonstrated that there is a mathematical correlation between titres measured by immunotitration and by classical plaque assay on MDCK cells. Moreover, the availability of NP antibodies specific for type A or type B influenza virus ensures the specificity of the assay. Based on speed, accuracy and specificity, it is concluded that the FACS-based immunotitration of influenza virus represents a valid and efficient alternative to the classical plaque assay.

  13. No Virological Evidence for an Influenza A - like Virus in European Bats

    PubMed Central

    Fereidouni, S.; Kwasnitschka, L.; Buschmann, A. Balkema; Müller, T.; Freuling, C.; Schatz, J.; Pikula, J.; Bandouchova, H.; Hoffmann, R.; Ohlendorf, B.; Kerth, G.; Tong, S.; Donis, R.; Beer, M.; Harder, T.

    2016-01-01

    Summary New members of the influenza A virus genus have been detected recently in bats from South America. By molecular investigations, using a generic real-time RT-PCR (RT-qPCR) that detects all previously known influenza A virus subtypes (H1–H16) and a newly developed RT-qPCR specific for the South American bat influenza-like virus of subtype H17 a total of 1571 samples obtained from 1369 individual bats of 26 species from Central Europe were examined. No evidence for the occurrence of such influenza viruses was found. Further attempts towards a more comprehensive evaluation of the role of bats in the ecology and epidemiology of influenza viruses should be based on more intense monitoring efforts. However, given the protected status of bats, not only in Europe, such activities need to be embedded into existing pathogen-monitoring programs PMID:24837569

  14. 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.

  15. Detection of influenza viruses in throat swab by using polymerase chain reaction.

    PubMed

    Yamada, A; Imanishi, J; Nakajima, E; Nakajima, K; Nakajima, S

    1991-01-01

    An assay protocol based on exploiting the polymerase chain reaction (PCR) for the direct detection of influenza virus in throat swab is described. By use of the mixture of H1 and H3 primers, it was possible to determine the subtype of the influenza A viruses simultaneously. No visible band was detected after PCR of influenza B or A (H2N2) viruses with a pair of H1 or H3 primers. The dilution experiment showed that the influenza viruses, as few as 1.3-6 plaque-forming units, were sufficient for detecting the HA gene by PCR. All throat swab samples from which influenza viruses had been isolated by conventional method were also positively detected by PCR method.

  16. Recombinant measles virus incorporating heterologous viral membrane proteins for use as vaccines.

    PubMed

    Swett-Tapia, Cindy; Bogaert, Lies; de Jong, Pascal; van Hoek, Vladimir; Schouten, Theo; Damen, Irma; Spek, Dirk; Wanningen, Patrick; Radošević, Katarina; Widjojoatmodjo, Myra N; Zahn, Roland; Custers, Jerome; Roy, Soumitra

    2016-09-01

    Recombinant measles virus (rMV) vectors expressing heterologous viral membrane protein antigens are potentially useful as vaccines. Genes encoding the mumps virus haemagglutinin-neuraminidase (MuV-HN), the influenza virus haemagglutinin (Flu-HA) or the respiratory syncytial virus fusion (RSV-F) proteins were inserted into the genome of a live attenuated vaccine strain of measles virus. Additionally, in this case rMV with the MuV-HN or the influenza HA inserts, chimeric constructs were created that harboured the measles virus native haemagglutinin or fusion protein cytoplasmic domains. In all three cases, sucrose-gradient purified preparations of rMV were found to have incorporated the heterologous viral membrane protein on the viral membrane. The possible utility of rMV expressing RSV-F (rMV.RSV-F) as a vaccine was tested in a cotton rat challenge model. Vaccination with rMV.RSV-F efficiently induced neutralizing antibodies against RSV and protected animals from infection with RSV in the lungs. PMID:27311834

  17. Inhibitory effects of quercetin 3-rhamnoside on influenza A virus replication.

    PubMed

    Choi, Hwa Jung; Song, Jae Hyoung; Park, Kwi Sung; Kwon, Dur Han

    2009-06-28

    Influenza viruses cause significant morbidity and mortality in humans through epidemics or pandemics. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Flavonoids widely exist in the plant kingdom, and their antiviral activities against various viruses have been recently reported. In this study, the anti-influenza A/WS/33 virus of quercetin 3-rhamnoside (Q3R) from Houttuynia cordata was evaluated using a cytopathic effect (CPE) reduction method, the assay results demonstrated that Q3R possessed strong anti-influenza A/WS/33 virus reducing the formation of a visible CPE. Q3R also did inhibit virus replication in the initial stage of virus infection by indirect interaction with virus particles. However, oseltamivir has relative weaker efficacy compared to Q3R. Therefore, these findings provide important information for the utilization of Q3R for influenza treatment.

  18. Human microRNA-24 modulates highly pathogenic avian-origin H5N1 influenza A virus infection in A549 cells by targeting secretory pathway furin.

    PubMed

    Loveday, Emma-Kate; Diederich, Sandra; Pasick, John; Jean, François

    2015-01-01

    A common critical cellular event that many human enveloped viruses share is the requirement for proteolytic cleavage of the viral glycoprotein by furin in the host secretory pathway. For example, the furin-dependent proteolytic activation of highly pathogenic (HP) influenza A (infA) H5 and H7 haemagglutinin precursor (HA0) subtypes is critical for yielding fusion-competent infectious virions. In this study, we hypothesized that viral hijacking of the furin pathway by HP infA viruses to permit cleavage of HA0 could represent a novel molecular mechanism controlling the dynamic production of fusion-competent infectious virus particles during the viral life cycle. We explored the biological role of a newly identified furin-directed human microRNA, miR-24, in this process as a potential post-transcriptional regulator of the furin-mediated activation of HA0 and production of fusion-competent virions in the host secretory pathway. We report that miR-24 and furin are differentially expressed in human A549 cells infected with HP avian-origin infA H5N1. Using miR-24 mimics, we demonstrated a robust decrease in both furin mRNA levels and intracellular furin activity in A549 cells. Importantly, pretreatment of A549 cells with miR-24 mimicked these results: a robust decrease of H5N1 infectious virions and a complete block of H5N1 virus spread that was not observed in A549 cells infected with low-pathogenicity swine-origin infA H1N1 virus. Our results suggest that viral-specific downregulation of furin-directed microRNAs such as miR-24 during the life cycle of HP infA viruses may represent a novel regulatory mechanism that governs furin-mediated proteolytic activation of HA0 glycoproteins and production of infectious virions.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. 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.

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

    PubMed Central

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

    2012-01-01

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

  2. 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

  3. Replication-competent influenza A viruses expressing a red fluorescent protein.

    PubMed

    Nogales, Aitor; Baker, Steven F; Martínez-Sobrido, Luis

    2015-02-01

    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.

  4. Ubiquitin in Influenza Virus Entry and Innate Immunity

    PubMed Central

    Rudnicka, Alina; Yamauchi, Yohei

    2016-01-01

    Viruses are obligatory cellular parasites. Their mission is to enter a host cell, to transfer the viral genome, and to replicate progeny whilst diverting cellular immunity. The role of ubiquitin is to regulate fundamental cellular processes such as endocytosis, protein degradation, and immune signaling. Many viruses including influenza A virus (IAV) usurp ubiquitination and ubiquitin-like modifications to establish infection. In this focused review, we discuss how ubiquitin and unanchored ubiquitin regulate IAV host cell entry, and how histone deacetylase 6 (HDAC6), a cytoplasmic deacetylase with ubiquitin-binding activity, mediates IAV capsid uncoating. We also discuss the roles of ubiquitin in innate immunity and its implications in the IAV life cycle. PMID:27783058

  5. Influenza D virus infection in Mississippi beef cattle.

    PubMed

    Ferguson, Lucas; Eckard, Laura; Epperson, William B; Long, Li-Ping; Smith, David; Huston, Carla; Genova, Suzanne; Webby, Richard; Wan, Xiu-Feng

    2015-12-01

    A new member of the Orthomyxoviridae family, influenza D virus (IDV), was first reported in swine in the Midwest region of the United States. This study aims to extend our knowledge on the IDV epidemiology and to determine the impact of bovine production systems on virus spread. A total of 15 isolates were recovered from surveillance of bovine herds in Mississippi, and two genetic clades of viruses co-circulated in the same herd. Serologic assessment from neonatal beef cattle showed 94% seropositive, and presumed maternal antibody levels were substantially lower in animals over six months of age. Active IDV transmission was shown to occur at locations where young, weaned, and comingled calves were maintained. Serological characterization of archived sera suggested that IDV has been circulating in the Mississippi cattle populations since at least 2004. Continuous surveillance is needed to monitor the evolution and epidemiology of IDV in the bovine population.

  6. Influenza D virus infection in Mississippi beef cattle.

    PubMed

    Ferguson, Lucas; Eckard, Laura; Epperson, William B; Long, Li-Ping; Smith, David; Huston, Carla; Genova, Suzanne; Webby, Richard; Wan, Xiu-Feng

    2015-12-01

    A new member of the Orthomyxoviridae family, influenza D virus (IDV), was first reported in swine in the Midwest region of the United States. This study aims to extend our knowledge on the IDV epidemiology and to determine the impact of bovine production systems on virus spread. A total of 15 isolates were recovered from surveillance of bovine herds in Mississippi, and two genetic clades of viruses co-circulated in the same herd. Serologic assessment from neonatal beef cattle showed 94% seropositive, and presumed maternal antibody levels were substantially lower in animals over six months of age. Active IDV transmission was shown to occur at locations where young, weaned, and comingled calves were maintained. Serological characterization of archived sera suggested that IDV has been circulating in the Mississippi cattle populations since at least 2004. Continuous surveillance is needed to monitor the evolution and epidemiology of IDV in the bovine population. PMID:26386554

  7. 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

  8. 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 viru