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Sample records for influenza virus haemagglutinin

  1. The International Reference Preparation of Influenza Virus Haemagglutinin (Type A)

    PubMed Central

    Krag, P.; Bentzon, M. Weis

    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. PMID:5317082

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

    PubMed Central

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

    2016-01-01

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

  3. Enhanced virulence of influenza A viruses with the haemagglutinin of the 1918 pandemic virus.

    PubMed

    Kobasa, Darwyn; Takada, Ayato; Shinya, Kyoko; Hatta, Masato; Halfmann, Peter; Theriault, Steven; Suzuki, Hiroshi; Nishimura, Hidekazu; Mitamura, Keiko; Sugaya, Norio; Usui, Taichi; Murata, Takeomi; Maeda, Yasuko; Watanabe, Shinji; Suresh, M; Suzuki, Takashi; Suzuki, Yasuo; Feldmann, Heinz; Kawaoka, Yoshihiro

    2004-10-07

    The 'Spanish' influenza pandemic of 1918-19 was the most devastating outbreak of infectious disease in recorded history. At least 20 million people died from their illness, which was characterized by an unusually severe and rapid clinical course. The complete sequencing of several genes of the 1918 influenza virus has made it possible to study the functions of the proteins encoded by these genes in viruses generated by reverse genetics, a technique that permits the generation of infectious viruses entirely from cloned complementary DNA. Thus, to identify properties of the 1918 pandemic influenza A strain that might be related to its extraordinary virulence, viruses were produced containing the viral haemagglutinin (HA) and neuraminidase (NA) genes of the 1918 strain. The HA of this strain supports the pathogenicity of a mouse-adapted virus in this animal. Here we demonstrate that the HA of the 1918 virus confers enhanced pathogenicity in mice to recent human viruses that are otherwise non-pathogenic in this host. Moreover, these highly virulent recombinant viruses expressing the 1918 viral HA could infect the entire lung and induce high levels of macrophage-derived chemokines and cytokines, which resulted in infiltration of inflammatory cells and severe haemorrhage, hallmarks of the illness produced during the original pandemic.

  4. Antigenic and sequence analysis of H3 influenza virus haemagglutinins from pigs in Italy.

    PubMed

    Castrucci, M R; Campitelli, L; Ruggieri, A; Barigazzi, G; Sidoli, L; Daniels, R; Oxford, J S; Donatelli, I

    1994-02-01

    To investigate the possible mechanism of maintenance of old human influenza A (H3N2) viruses in pigs, the haemagglutinins (HAs) of seven isolates from swine were studied by analysis of nucleotide and deduced primary amino acid sequences, as well as reactivity of the HA molecule to chicken antisera and monoclonal antibodies. The swine HAs were closely similar to the HA of the A/Victoria/3/75 human variant as regards antigenic and molecular characteristics. These findings are consistent with the hypothesis that the swine HA genes were transmitted from an early human H3 virus to pigs, where they survived with limited mutations over a period of 5 years. The sequence data were also compared with swine H3 sequences to investigate genetic relationships between the H3 genes from swine viruses isolated in different geographical areas. An evolutionary tree, constructed from the nucleotide sequences of viruses isolated from pigs in China and in Italy, illustrated that, depending on the country of their isolation, the HA genes of swine influenza A (H3N2) viruses have different origins, e.g. human and avian, and evolved independently in different lineages. The study provides direct support for the hypothesis that pigs might serve as a 'mixing vessel' for the generation of pandemic strains of human influenza viruses.

  5. Complete nucleotide sequence of the haemagglutinin gene from a human influenza virus of the Hong Kong subtype.

    PubMed Central

    Both, G W; Sleigh, M J

    1980-01-01

    The complete nucleotide sequence has been determined for a cloned double-stranded DNA copy of the haemagglutinin gene from the human influenza strain A/NT/60/68/29C, a laboratory-isolated variant of A/NT/60/68, an early strain of the Hong Kong subtype. The gene is 1765 nucleotides long and contains information sufficient to code for a protein of 566 amino acids, which includes a hydrophobic leader peptide (16 residues), HA1 (328), HA2 (221) and an arginine residue which joins the HA subunits. Comparison of the predicted amino acid sequence for 29C haemagglutinin with protein sequence data available for HA from other influenza strains shows that no potential coding information is lost by processing of the mRNA. A comparison of the amino acid sequences predicted from the gene sequences for 29C and fowl plague virus haemagglutinins, (1) indicates the extent to which changes can occur in the primary sequence of different regions of the protein, while maintaining essential structure and function. Images PMID:6253883

  6. Quantifying selection and diversity in viruses by entropy methods, with application to the haemagglutinin of H3N2 influenza

    PubMed Central

    Pan, Keyao; Deem, Michael W.

    2011-01-01

    Many viruses evolve rapidly. For example, haemagglutinin (HA) of the H3N2 influenza A virus evolves to escape antibody binding. This evolution of the H3N2 virus means that people who have previously been exposed to an influenza strain may be infected by a newly emerged virus. In this paper, we use Shannon entropy and relative entropy to measure the diversity and selection pressure by an antibody in each amino acid site of H3 HA between the 1992–1993 season and the 2009–2010 season. Shannon entropy and relative entropy are two independent state variables that we use to characterize H3N2 evolution. The entropy method estimates future H3N2 evolution and migration using currently available H3 HA sequences. First, we show that the rate of evolution increases with the virus diversity in the current season. The Shannon entropy of the sequence in the current season predicts relative entropy between sequences in the current season and those in the next season. Second, a global migration pattern of H3N2 is assembled by comparing the relative entropy flows of sequences sampled in China, Japan, the USA and Europe. We verify this entropy method by describing two aspects of historical H3N2 evolution. First, we identify 54 amino acid sites in HA that have evolved in the past to evade the immune system. Second, the entropy method shows that epitopes A and B on the top of HA evolve most vigorously to escape antibody binding. Our work provides a novel entropy-based method to predict and quantify future H3N2 evolution and to describe the evolutionary history of H3N2. PMID:21543352

  7. Generation of monoclonal antibodies reactive against subtype specific conserved B-cell epitopes on haemagglutinin protein of influenza virus H5N1.

    PubMed

    Fiebig, Petra; Shehata, Awad A; Liebert, Uwe G

    2015-03-02

    H5-specific monoclonal antibodies may serve as valuable tools for rapid diagnosis of H5N1 avian influenza virus. Therefore, conserved H5-specific sequences of the haemagglutinin (HA) protein were expressed in Pichia pastoris and used for generation of monoclonal antibodies (mAbs). The two mAbs, FD6 and HE4, were strongly reactive against native HA protein and exhibited specificity for subtype H5. By epitope mapping linear epitopes of mAbs were identified that are highly conserved among influenza A virus of subtype H5. Additionally no sequence similarities to homologous regions on HA proteins of other influenza A virus subtypes (i.e. H1, H3, H7, H9) were detected by sequence alignment analysis. Both mAbs did not cross react with native or denatured HA proteins of other influenza A virus subtypes. Furthermore, using ELISA and immunofluorescence test mAb FD6 reacted only to the native H5 protein of recently circulating highly pathogenic H5N1 influenza viruses but not to low pathogenic H5N1 isolates. In conclusion, the use of the two mAbs in non-molecular tests like antigen-capture-ELISA appears promising for detecting influenza A H5N1 virus.

  8. 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.

  9. 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.

  10. Review of the literature on avian influenza A viruses in pigeons and experimental studies on the susceptibility of domestic pigeons to influenza A viruses of the haemagglutinin subtype H7.

    PubMed

    Kaleta, E F; Hönicke, A

    2004-12-01

    The scientific literature of the past century is reviewed on fowl plague (presently termed highly pathogenic avian influenza, HPAI) in pigeons. HPAI viruses cause epidemic disease outbreaks with high rates of losses in many avian species, particularily in chickens and turkeys. Also susceptible to disease are quails, guinea fowl, ducks, geese, ostriches, passerine birds, and birds of prey whereas conflicting reports on the susceptibility of the domestic pigeon exist. Based on literature reports and on own experiments, and applying as criteria for judgements clinically overt forms of disease, virus multiplication plus shedding and seroconversion, it is concluded that domestic pigeons are only partially susceptible to influenza A viruses of the haemagglutinin subtype H7. Infection of pigeons with H7 viruses results only in some of them in signs, virus shedding and seroconversion. Using the same criteria, pigeons appear to be even less susceptible to infection with influenza A viruses of the H5 subtype. Only one of five publications describe in 1/19 pigeons exposed to H5 influenza A virus depression one day before death, and only 2/19 multiplied and excreted virus, and 1/19 developed circulating antibodies. Consequently, pigeons play only a minor role in the epidemiology of H5 influenza viruses. In contrast, following infection with influenza A virus of the subtype H7 clinical signs in pigeons consist of conjunctivitis, tremor, paresis of wings and legs, and wet droppings. H7-infected pigeons multiply and excrete H7 viruses and develop circulating antibodies. Albeit of the status of infection, free-flying domestic pigeons can act as mechanical vectors and vehicles for long-distance transmission of any influenza A virus if plumage or feet were contaminated.

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

    PubMed

    Ogata, Norio

    2012-12-01

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

  12. Cell wall biochemical alterations during Agrobacterium-mediated expression of haemagglutinin-based influenza virus-like vaccine particles in tobacco.

    PubMed

    Le Mauff, François; Loutelier-Bourhis, Corinne; Bardor, Muriel; Berard, Caroline; Doucet, Alain; D'Aoust, Marc-André; Vezina, Louis-Philippe; Driouich, Azeddine; Couture, Manon M-J; Lerouge, Patrice

    2017-03-01

    Influenza virus-like particles (VLPs) have been shown to induce a safe and potent immune response through both humoral and cellular responses. They represent promising novel influenza vaccines. Plant-based biotechnology allows for the large-scale production of VLPs of biopharmaceutical interest using different model organisms, including Nicotiana benthamiana plants. Through this platform, influenza VLPs bud from the plasma membrane and accumulate between the membrane and the plant cell wall. To design and optimize efficient production processes, a better understanding of the plant cell wall composition of infiltrated tobacco leaves is a major interest for the plant biotechnology industry. In this study, we have investigated the alteration of the biochemical composition of the cell walls of N. benthamiana leaves subjected to abiotic and biotic stresses induced by the Agrobacterium-mediated transient transformation and the resulting high expression levels of influenza VLPs. Results show that abiotic stress due to vacuum infiltration without Agrobacterium did not induce any detectable modification of the leaf cell wall when compared to non infiltrated leaves. In contrast, various chemical changes of the leaf cell wall were observed post-Agrobacterium infiltration. Indeed, Agrobacterium infection induced deposition of callose and lignin, modified the pectin methylesterification and increased both arabinosylation of RG-I side chains and the expression of arabinogalactan proteins. Moreover, these modifications were slightly greater in plants expressing haemagglutinin-based VLP than in plants infiltrated with the Agrobacterium strain containing only the p19 suppressor of silencing.

  13. Directionality in the evolution of influenza A haemagglutinin

    PubMed Central

    Kryazhimskiy, Sergey; Bazykin, Georgii A; Plotkin, Joshua; Dushoff, Jonathan

    2008-01-01

    The evolution of haemagglutinin (HA), an important influenza virus antigen, has been the subject of intensive research for more than two decades. Many characteristics of HA's sequence evolution are captured by standard Markov chain substitution models. Such models assign equal fitness to all accessible amino acids at a site. We show, however, that such models strongly underestimate the number of homoplastic amino acid substitutions during the course of HA's evolution, i.e. substitutions that repeatedly give rise to the same amino acid at a site. We develop statistics to detect individual homoplastic events and find that they preferentially occur at positively selected epitopic sites. Our results suggest that the evolution of the influenza A HA, including evolution by positive selection, is strongly affected by the long-term site-specific preferences for individual amino acids. PMID:18647721

  14. 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:27572837

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

    PubMed

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

    2015-09-01

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

  16. 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

  17. The predicted antigenicity of the haemagglutinin of the 1918 Spanish influenza pandemic suggests an avian origin.

    PubMed

    Brownlee, G G; Fodor, E

    2001-12-29

    In 1982 we characterized the antigenic sites of the haemagglutinin of influenza A/PR/8/34, which is an influenza strain of the H1 subtype that was isolated from humans in 1934, by studying mutants which escaped neutralization by antibody. Four antigenic sites, namely Cb, Sa, Sb and Ca, were found to be located near the tip of the trimeric haemagglutinin spike. Based on the sequence of the haemagglutinin of the 1918 Spanish influenza, we can now specify the extent of divergence of antigenic sites of the haemagglutinin during the antigenic drift of the virus between 1918 and 1934. This divergence was much more extensive (40%) than the divergence (20%) in predicted antigenic sites between the 1918 Spanish influenza and an avian H1 subtype consensus sequence. These results support the hypothesis that the human 1918 pandemic originated from an avian virus of the H1 subtype that crossed the species barrier from birds to humans and adapted to humans, presumably by mutation and/or reassortment, shortly before 1918.

  18. Heterogeneity in the haemagglutinin gene and emergence of the highly pathogenic phenotype among recent H5N2 avian influenza viruses from Mexico.

    PubMed

    García, M; Crawford, J M; Latimer, J W; Rivera-Cruz, E; Perdue, M L

    1996-07-01

    Molecular changes in the haemagglutinin (HA)-coding regions and proteolytic cleavage sites from multiple H5N2 subtype viruses isolated during a recent outbreak of avian influenza (AI) in central Mexico have been characterized. Eighteen isolates, collected during a 15 month period (October 1993 to January 1995) from six central states, were sequenced. None of the 18 predicted HA1 amino acid sequences were identical and changes were not restricted to a specific region of the sequence. Phylogenetic analyses of the HA1 sequences demonstrated two virus lineages, designated Puebla and Jalisco, with sequence variation as high as 10.5 percent for amino acid and 6.2 percent for nucleotide sequences. During the latter months of the surveillance period, highly pathogenic (HP) strains of AI emerged causing lethal disease in commercial poultry flocks. In each of the HP strains isolated, the HA protein was cleaved in chicken embryo fibroblast cells in the absence of trypsin, and two alterations not found in earlier non-HP isolates were detected. In the HA protein, HP strains all had a glutamic acid --> lysine substitution at amino acid position 324 and an insertion of arginine and lysine as new residues 325 and 326. The insertion appears to be due to a duplication of the nucleotide sequence AAAGAA at nucleotide positions 965-970 of the HA1-coding region. Computer-assisted secondary structure analyses place the target for the insertion in a predicted RNA stem-loop structure. A mechanism is suggested by which the polymerase duplicates the sequence.

  19. 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.

  20. Chimeric influenza haemagglutinins: Generation and use in pseudotype neutralization assays.

    PubMed

    Ferrara, Francesca; Temperton, Nigel

    2017-01-01

    Recently chimeric influenza haemagglutinins (cHAs) have been generated as potential 'universal' vaccination antigens and as tools to identify HA stalk-directed antibodies via their use as antigens in ELISA, and virus or pseudotype-based neutralization assays. The original methods [1], [2] used for their generation require the amplification of regions of interest (head and stalk) using primers containing SapI sites and subsequent cloning into pDZ plasmid. This requires precise primer design, checking for the absence of SapI sites in the sequence of interest, and multi-segment ligation. As an alternative strategy we have developed and optimized a new protocol for assembling the cHA by exploiting Gibson Assembly. •This method also requires precise primer design, but it is rapid and methodologically simple to perform. We have evaluated that using this method it is possible to construct a cHA encoding DNA in less than a week.•Additional weeks are however necessary to optimize the production of pseudotyped lentiviral particles and to perform neutralization assays using them as surrogate antigens.•In comparison to the original protocols, we have also observed that performing parallel neutralization assays using pseudotypes harbouring the two parental HAs, permits effective delineation between stalk and head antibody responses in the samples tested.

  1. 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

  2. A single-radial-immunodiffusion technique for the assay of influenza haemagglutinin antigen

    PubMed Central

    Schild, G. C.; Wood, J. M.; Newman, R. W.

    1975-01-01

    Single-radial-diffusion techniques are proposed as possible alternatives to tests based on agglutination of erythrocytes for the assay of the haemagglutinin content of influenza vaccines. Two test procedures (microtest and macrotest) and the use of reference reagents to assay vaccines using these tests are described. The two tests are of similar reproducibility and accuracy but the macrotest is technically simpler to perform and results of assays may be obtained more rapidly. ImagesFig. 1aFig. 3a PMID:816480

  3. 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

  4. Swine Influenza/Variant Influenza Viruses

    MedlinePlus

    ... Past Newsletters Information on Swine Influenza/Variant Influenza Virus Language: English Español Recommend on Facebook Tweet ... disease of pigs caused by type A influenza viruses that regularly cause outbreaks of influenza in pigs. ...

  5. [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.

  6. Rapid molecular haemagglutinin subtyping of avian influenza isolates by specific real-time RT-PCR tests.

    PubMed

    Elizalde, Maia; Agüero, Montserrat; Buitrago, Dolores; Yuste, María; Arias, María Luisa; Muñoz, María Jesús; Lelli, Davide; Pérez-Ramírez, Elisa; Moreno-Martin, Ana María; Fernández-Pinero, Jovita

    2014-02-01

    Sixteen haemagglutinin (HA) subtypes of avian influenza viruses (AIV) have been described to date. Rapid subtype identification of any AIV is of major interest because of the possible serious consequences for the poultry industry and even public health. Molecular techniques currently allow immediate accurate subtype characterisation prior to virus isolation. In this study, a set of fourteen specific real-time RT-PCR methods were developed and evaluated for AIV HA subtyping (H1-H4, H6-H8, H10-H16), H5 and H9 being excluded on the basis of the current validity of the European Union (EU) recommended specific assays. Specific primers and probes sets for each HA-subtype were designed to hybridise the largest isolates range within each single subtype, considering the Eurasian lineage as a major target. The robustness and general application of the 14 HA-subtype methods were verified by the analysis of 110 AIV isolates belonging to all 16 HA-subtypes, performed in different laboratories. The developed real-time RT-PCR assays proved to be highly specific and revealed suitable sensitivity, allowing direct HA-subtyping of clinical material. In summary, this study provides for the first time a panel of molecular tests using specific hydrolysis probes for rapid and complete AIV HA-subtype identification.

  7. Avian influenza viruses and human health.

    PubMed

    Alexander, D J

    2006-01-01

    Influenza A viruses cause natural infections of humans, some other mammals and birds. Few of the 16 haemagglutinin and nine neuraminidase subtype combinations have been isolated from mammals, but all subtypes have been isolated from birds. In the 20th century, there were four pandemics of influenza as a result of the emergence of antigenically different strains in humans: 1918 (H1N1), 1957 (H2N2), 1968 (H3N2) and 1977 (H1N1). Influenza A viruses contain eight distinct RNA genes and reassortment of these can occur in mixed infections with different viruses. The 1957 and 1968 pandemic viruses differed from the preceding viruses in humans by the substitution of genes that came from avian viruses, suggesting they arose by genetic reassortment of viruses of human and avian origin. Up to 1995, there had been only three reports of avian influenza viruses infecting humans, in 1959, 1977 and 1981 (all H7N7), but, since 1996, there have been regular reports of natural infections of humans with avian influenza viruses: in England in 1996 (H7N7), Hong Kong 1997 (H5N1), 1999 (H9N2), and 2003 (H5N1), in The Netherlands 2003 (H7N7), Canada 2004 (H7N3), Vietnam 2004 (H5N1) and Thailand 2004 (H5N1). The H5N1 virus is alarming because 51 (64 %) of the 80 people confirmed as infected since 1997 have died.

  8. Development and qualification of the parallel line model for the estimation of human influenza haemagglutinin content using the single radial immunodiffusion assay.

    PubMed

    van Kessel, G; Geels, M J; de Weerd, S; Buijs, L J; de Bruijni, M A M; Glansbeek, H L; van den Bosch, J F; Heldens, J G; van den Heuvel, E R

    2012-01-05

    Infection with human influenza virus leads to serious respiratory disease. Vaccination is the most common and effective prophylactic measure to prevent influenza. Influenza vaccine manufacturing and release is controlled by the correct determination of the potency-defining haemagglutinin (HA) content. This determination is historically done by single radial immunodiffusion (SRID), which utilizes a statistical slope-ratio model to estimate the actual HA content. In this paper we describe the development and qualification of a parallel line model for analysis of HA quantification by SRID in cell culture-derived whole virus final monovalent and trivalent influenza vaccines. We evaluated plate layout, sample randomization, and validity of data and statistical model. The parallel line model was shown to be robust and reproducible. The precision studies for HA content demonstrated 3.8-5.0% repeatability and 3.8%-7.9% intermediate precision. Furthermore, system suitability criteria were developed to guarantee long-term stability of this assay in a regulated production environment. SRID is fraught with methodological and logistical difficulties and the determination of the HA content requires the acceptance of new and modern release assays, but until that moment, the described parallel line model represents a significant and robust update for the current global influenza vaccine release assay.

  9. [Features of interepidemic influenza A and B viruses].

    PubMed

    Litvinova, O M; Grinbaum, E B; Bannikov, A I; Konovalenko, I B; Konovalova, N I; Luzianina, T Ia; Kiselev, O I

    1995-01-01

    The comparison of interepidemic influenza viruses with the pathogens of resultant influenza epidemics has revealed that they belong to the same type (subtype) of influenza virus. A definite correlation has been found between the antigenic specificity of haemagglutinin of epidemic and interepidemic strains. The antigenic structure of the interepidemic viruses and the pathogens of further epidemics of influenza B viruses have been found to be completely identical. The interepidemic A(H1N1) isolates have been shown to be antigenic analogues of the causative agents of influenza A(H1N1) during the previous epidemics. Despite the time and place of their isolation, as well as the etiology of the previous and subsequent epidemics, the interepidemic influenza A(H3N2) viruses have been ascertained to be similar to the reference A/Bangkok/1/79.

  10. 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

  11. Equine influenza virus.

    PubMed

    Landolt, Gabriele A

    2014-12-01

    For decades the horse has been viewed as an isolated or "dead-end" host for influenza A viruses, with equine influenza virus being considered as relatively stable genetically. Although equine influenza viruses are genetically more stable than those of human lineage, they are by no means in evolutionary stasis. Moreover, recent transmission of equine-lineage influenza viruses to dogs also challenges the horse's status as a dead-end host. This article reviews recent developments in the epidemiology and evolution of equine influenza virus. In addition, the clinical presentation of equine influenza infection, diagnostic techniques, and vaccine recommendations are briefly summarized.

  12. Infection of influenza virus neuraminidase-vaccinated mice with homologous influenza virus leads to strong protection against heterologous influenza viruses.

    PubMed

    He, Biao; Chang, Haiyan; Liu, Zhihua; Huang, Chaoyang; Liu, Xueying; Zheng, Dan; Fang, Fang; Sun, Bing; Chen, Ze

    2014-12-01

    Vaccination is the best measure to prevent influenza pandemics. Here, we studied the protective effect against heterologous influenza viruses, including A/reassortant/NYMC X-179A (pH1N1), A/Chicken/Henan/12/2004 (H5N1), A/Chicken/Jiangsu/7/2002 (H9N2) and A/Guizhou/54/89×A/PR/8/34 (A/Guizhou-X) (H3N2), in mice first vaccinated with a DNA vaccine of haemagglutinin (HA) or neuraminidase (NA) of A/PR/8/34 (PR8) and then infected with the homologous virus. We showed that PR8 HA or NA vaccination both protected mice against a lethal dose of the homologous virus; PR8 HA or NA DNA vaccination and then PR8 infection in mice offered poor or excellent protection, respectively, against a second, heterologous influenza virus challenge. In addition, before the second heterologous influenza infection, the highest antibody level against nucleoprotein (NP) and matrix (M1 and M2) proteins was found in the PR8 NA-vaccinated and PR8-infected group. The level of induced cellular immunity against NP and M1 showed a trend consistent with that seen in antibody levels. However, PR8 HA+NA vaccination and then PR8 infection resulted in limited protection against heterologous influenza virus challenge. Results of the present study demonstrated that infection of the homologous influenza virus in mice already immunized with a NA vaccine could provide excellent protection against subsequent infection of a heterologous influenza virus. These findings suggested that NA, a major antigen of influenza virus, could be an important candidate antigen for universal influenza vaccines.

  13. 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...

  14. 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

  15. Avian influenza virus.

    PubMed

    Lee, Chang-Won; Saif, Yehia M

    2009-07-01

    Avian influenza viruses do not typically replicate efficiently in humans, indicating direct transmission of avian influenza virus to humans is unlikely. However, since 1997, several cases of human infections with different subtypes (H5N1, H7N7, and H9N2) of avian influenza viruses have been identified and raised the pandemic potential of avian influenza virus in humans. Although circumstantial evidence of human to human transmission exists, the novel avian-origin influenza viruses isolated from humans lack the ability to transmit efficiently from person-to-person. However, the on-going human infection with avian-origin H5N1 viruses increases the likelihood of the generation of human-adapted avian influenza virus with pandemic potential. Thus, a better understanding of the biological and genetic basis of host restriction of influenza viruses is a critical factor in determining whether the introduction of a novel influenza virus into the human population will result in a pandemic. In this article, we review current knowledge of type A influenza virus in which all avian influenza viruses are categorized.

  16. 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.

  17. Filamentous Influenza Viruses

    PubMed Central

    Badham, Matthew D.; Rossman, Jeremy S.

    2016-01-01

    Influenza A virus is a pathogen of global medical importance causing significant health and socio-economic costs every year. Influenza virus is an unusual pathogen in that it is pleomorphic, capable of forming virions ranging in shape from spherical to filamentous. Despite decades of research on the influenza virus, much remains unknown about the formation of filamentous influenza viruses and their role in the viral replication cycle. Here, we discuss what is known about influenza virus assembly and budding, focusing on the viral and host factors that are involved in the determination of viral morphology. Whilst the biological function of the filamentous morphology remains unknown, recent results suggest a role in facilitating viral spread in vivo. We discuss these results and speculate on the consequences of viral morphology during influenza virus infection of the human respiratory tract. PMID:28042529

  18. Avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) is caused by type A influenza virus, a member of the Orthomyxoviridae family. AI viruses are serologically categorized into 16 hemagglutinin (H1-H16) and 9 neuraminidase (N1-N9) subtypes. All subtypes have been identified in birds. Infections by AI viruses have been reported in ...

  19. Avian glycan-specific IgM monoclonal antibodies for the detection and quantitation of type A and B haemagglutinins in egg-derived influenza vaccines.

    PubMed

    Legastelois, Isabelle; Chevalier, Michel; Bernard, Marie-Clotilde; de Montfort, Aymeric; Fouque, Martine; Pilloud, Alexandra; Serraille, Christelle; Devard, Nicolas; Engel, Olivier; Sodoyer, Régis; Moste, Catherine

    2011-12-01

    Two IgM monoclonal antibodies (MAbs), Y6F5 and Y13F9, were selected during a screening of clones obtained immunising BALB/c mice with purified envelop proteins of the A/Sydney/5/97 (H3N2) IVR108 influenza strain. These MAbs recognised avian glycans on the haemagglutinin (HA) of the virus. This broad recognition allowed these MAbs to be used as enzyme-labelled secondary antibody reagents in a strain specific enzyme-linked immunosorbent assay (ELISA) in combination with a capture MAb that recognised and allowed the quantitation of the strain specific HA protein present in an egg-produced influenza vaccine. Advantage was taken of these MAbs to develop a universal ELISA in which the MAbs were used both as capture antibody and as enzyme-labelled secondary antibody to detect and quantify the HA protein of any egg-derived influenza vaccine. These avian-glycan specific IgM MAbs may prove to be particularly useful for determining the HA concentration in monovalent egg-derived pandemic influenza vaccines, in which the HA concentration may be lower than 5μg/ml. The HA detection limit in the ELISA assays developed in this study was 1.9μg/ml, as opposed to the 5μg/ml quantitation limit generally accepted for the standard single-radial-immunodiffusion (SRID) assay, the approved technique for quantifying HA content in influenza vaccines. These ELISAs can also be used to quantify influenza HA formulated with emulsion-based or mineral salt adjuvants that could interfere with HA measurement by the SRID assay.

  20. Structure of the haemagglutinin-neuraminidase from human parainfluenza virus type III.

    PubMed

    Lawrence, Michael C; Borg, Natalie A; Streltsov, Victor A; Pilling, Patricia A; Epa, V Chandana; Varghese, Joseph N; McKimm-Breschkin, Jennifer L; Colman, Peter M

    2004-01-30

    The three-dimensional structure of the haemagglutinin-neuraminidase (HN) from a human parainfluenza virus is described at ca 2.0 A resolution, both in native form and in complex with three substrate analogues. In support of earlier work on the structure of the homologous protein from the avian pathogen Newcastle disease virus (NDV), we observe a dimer of beta-propellers and find no evidence for spatially separated sites performing the receptor-binding and neuraminidase functions of the protein. As with the NDV HN, the active site of the HN of parainfluenza viruses is structurally flexible, suggesting that it may be able to switch between a receptor-binding state and a catalytic state. However, in contrast to the NDV structures, we observe no ligand-induced structural changes that extend beyond the active site and modify the dimer interface.

  1. Avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) is type A influenza that is adapted to avian host species. Although the virus can be isolated from numerous avian species, the natural host reservoir species are dabbling ducks, shorebirds and gulls. Domestic poultry species (poultry being defined as birds that are rais...

  2. [Fowl plague and avian influenza A viruses of poultry and birds. Diagnosis, control measures and practical experiences].

    PubMed

    Kaleta, E F

    2014-01-01

    The causes of the notifiable fowl plague are high and low pathogenic avian influenza A viruses of the haemagglutinin subtypes H5 and H7 but also other haemagglutinin subtypes If the intravenous pathogenicity index is greater than 1.2. The German fowl plague order (Geflügelpest-Verordnung) differentiates between highly pathogenic influenza A viruses of the subtypes H5 and H7, if multiple basic amino acids at the cleavage site of the haemagglutinin molecules are detected by virus isolation, antigen or genome determination and low pathogenic avian influenza A viruses of the subtypes H5 and H7 if either the intravenous pathogenicity index is lower than 1.2 or no basic amino acids are present at the cleavage site of the haemagglutinin molecule. Aspects of diagnosis, control including culling, therapy and vaccination are reviewed. The currently available means and their limitations of a therapy of fowl plague by oral administration of neuraminidase inhibitors (e. g. oseltamivir) are described. Following granted permission, individually marked valuable zoo and pet birds may be vaccinated using licensed inactivated vaccines. Vector vaccines have not been used in Germany so far. Avian influenza A viruses of other haemagglutinin subtypes (H1-H4, H6, H8-H18) may also cause infections and severe disease. These subtypes are not subject to governmental interventions and disease can be prevented by timely use of inactivated vaccines.

  3. Expression of avian influenza haemagglutinin (H5) and chicken interleukin 2 (chIL-2) under control of the ptcB promoter in Lactococcus lactis.

    PubMed

    Szatraj, Katarzyna; Szczepankowska, Agnieszka K; Sączyńska, Violetta; Florys, Katarzyna; Gromadzka, Beata; Łepek, Krzysztof; Płucienniczak, Grażyna; Szewczyk, Bogusław; Zagórski-Ostoja, Włodzimierz; Bardowski, Jacek

    2014-01-01

    Gram-positive and nonpathogenic lactic acid bacteria (LAB) are considered to be promising candidates for the development of new, safe systems of heterologous protein expression. Recombinant LAB has been shown to induce specific local and systemic immune response against selected pathogens, and could be a good alternative to classical attenuated carriers. The main goal of our study was to express the avian influenza haemagglutinin (H5) and chicken interleukin 2 (chIL-2) in Lactococcus lactis. Results of this study were anticipated to lead to construction of lactococcal strain(s) with potential vaccine properties against the avian influenza A (H5N1) virus. Expression of the cloned H5 gene, its His-tagged variant and chIL-2 gene, under the control of the ptcB gene promoter was attested by RT-PCR on transcriptional level and Western or dot blot analysis on translational level, demonstrating that system can be an attractive solution for production of heterologous proteins. The results of the preliminary animal trial conducted in mice are a promising step toward development of a vaccine against avian bird flu using Lactococcus lactis cells as antigen carriers.

  4. Avian Influenza A Virus Infections in Humans

    MedlinePlus

    ... this? Submit Button Past Newsletters Avian Influenza A Virus Infections in Humans Language: English Español Recommend ... with Avian Influenza A Viruses Avian Influenza A Virus Infections in Humans Although avian influenza A viruses ...

  5. 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.

  6. Influenza virus isolation.

    PubMed

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

    2012-01-01

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

  7. 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.

  8. Selection of antigenically advanced variants of seasonal influenza viruses

    PubMed Central

    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; 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. Further, we 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

  9. [Wild birds--a reservoir for influenza A virus].

    PubMed

    Griot, C; Hoop, R

    2007-11-01

    Influenza A viruses, in particular the H5 and H7 subtypes, have caused epizootic diseases in poultry for a long time. Wild aquatic birds and shorebirds form the natural virus reservoir. All influenza virus subtypes and almost all possible haemagglutinin/neuraminidase combinations have been detected in wild birds, whereas relatively few have been detected in humans and other mammals. In 1997, the emerging and spreading of the highly pathogenic strain H5N1 within Asia was supported by lack of hygiene in commercial poultry units and by the existence of live bird markets. During autumn 2005, migratory birds have been accused for spreading the infection along their flyways to Europe including Switzerland. For early detection of introduction to Europe, many countries have initiated surveillance programs for avian influenza in wild birds. Vaccines against influenza A viruses are existing for birds and are widely used to protect domestic fowl in endemic regions of Asia as well as valuable birds in zoos worldwide. Subtype H5N1 could be the progenitor virus of a new pandemic influenza virus. Therefore, the World Organisation for Animal Health (OIE, Paris) as well as the Food and Agriculture Organisation of the United Nations (FAO, Rome) will need to increase their efforts to assist countries to combat the disease in the field.

  10. Diversity of influenza A virus subtypes isolated from domestic poultry in Hong Kong.

    PubMed

    Shortridge, K F; Butterfield, W K; Webster, R G; Campbell, C H

    1979-01-01

    The second phase of a 2-year influenza virus surveillance programme of domestic avian species in Hong Kong (up to October 1977) yielded influenza A virus, Newcastle disease virus, and Hong Kong paramyxovirus, as well as unidentified haemagglutinating agents. These viruses were isolated from the trachea or cloaca of apparently healthy domestic ducks, geese, and chickens originating from China and Hong Kong. Twenty-five combinations of haemagglutinin and neuraminidase surface antigens were identified from the 136 influenza A viruses isolated. Eight of the combinations do not appear to have been previously reported - Hav3Nav2, Hav4Nav2, Hav4Nav4, Hav4Nav5, Hav4Neq1, Hav6Nav4, Hav6Nav6, and Hav9Nav1. The existence of such a diverse pool of influenza virus genetic information may play a role in the emergence of new human pandemic strains.

  11. 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

  12. Influenza viruses: transmission between species.

    PubMed

    Webster, R G; Hinshaw, V S; Bean, W J; Sriram, G

    1980-02-25

    The only direct evidence for transmission of influenza viruses between species comes from studies on swine influenza viruses. Antigenically and genetically identical Hsw1N1 influenza viruses were isolated from pigs and man on the same farm in Wisconsin, U.S.A. The isolation of H3N2 influenza viruses from a wide range of lower animals and birds suggests that influenza viruses of man can spread to the lower orders. Under some conditions the H3N2 viruses can persist for a number of years in some species. The isolation, from aquatic birds, of a large number of influenza A viruses that possess surface proteins antigenically similar to the viruses isolated from man, pigs and horses provides indirect evidence for inter-species transmission. There is now a considerable body of evidence which suggests that influenza viruses of lower animals and birds may play a role in the origin of some of the pandemic strains of influenza A viruses. There is no direct evidence that the influenza viruses in aquatic birds are transmitted to man, but they may serve as a genetic pool from which some genes may be introduced into humans by recombination. Preliminary evidence suggests that the molecular basis of host range and virulence may be related to the RNA segments coding for one of the polymerase proteins (P3) and for the nucleoprotein (NP).

  13. [Anti-influenza virus agent].

    PubMed

    Nakamura, Shigeki; Kohno, Shigeru

    2012-04-01

    The necessity of newly anti-influenza agents is increasing rapidly after the prevalence of pandemic influenza A (H1N1) 2009. In addition to the existing anti-influenza drugs, novel neuraminidase inhibitors such as peramivir (a first intravenous anti-influenza agent) and laninamivir (long acting inhaled anti-influenza agent) can be available. Moreover favipiravir, which shows a novel anti-influenza mechanism acting as RNA polymerase inhibitor, has been developing. These drugs are expected to improve the prognosis of severe cases caused by not only seasonal influenza but pandemic influenza A (H1N1) 2009 virus and H5N1 avian influenza, and also treat oseltamivir-resistant influenza effectively.

  14. 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. PMID:27818728

  15. Replication of two influenza virus strains and a recombinant in HEF and LEP cells.

    PubMed

    Ghendon, Y; Tucková, E; Vonka, V; Klimov, A; Ginzburg, V; Markushin, S

    1979-07-01

    The replication of influenza viruses A/NWS-D, A/WS-MK and their r12 recombinant in human embryo fibroblast (HEF) and human diploid fibroblast (LEP) cell lines was studied. In HEF cells virus NWS-D and recombinant r12 induced synthesis of virus-specific macromolecules and produced infectious virions; virus WS-MK induced synthesis of virus complementary RNA (cRNA), virion RNA (vRNA), protein, RNP and non-infectious virions, but haemagglutinin cleavage was impaired and the virions formed contained uncleaved haemagglutinin. In LEP cells, infectious virions were formed only by virus NWS-D; viruses WS-MK and r12 induced synthesis of virus cRNA, vRNA, proteins and RNP; virus r12 had the haemagglutinin cleaved, whereas in virus WS-MK this process was impaired; neither virus WS-MK nor r12 was capable of forming virions. Analysis of the recombinant r12 genome showed that it had only inherited a single gene from NWS-D, the one coding for neuraminidase, having inherited all others (P1, P2, P3, HA, NP, M, NS) from WS-MK. The data obtained suggested that the inability of virus WS-MK to form infectious virions in HEF cells is due to the character of its neuraminidase, which is incapable of participating in haemagglutinin cleavage. The deficient reproduction of this virus in the other host-cell system (LEP) is apparently associated with some characteristics of another protein (other proteins) of this virus.

  16. Influenza A Virus in Backyard Pigs and Poultry in Rural Cambodia.

    PubMed

    Osbjer, K; Berg, M; Sokerya, S; Chheng, K; San, S; Davun, H; Magnusson, U; Olsen, B; Zohari, S

    2016-08-02

    Surveillance of influenza virus in humans and livestock is critical, given the worldwide public health threats and livestock production losses. Livestock farming involving close proximity between humans, pigs and poultry is often practised by smallholders in low-income countries and is considered an important driver of influenza virus evolution. This study determined the prevalence and genetic characteristics of influenza A virus (IAV) in backyard pigs and poultry in Cambodia. A total of 751 animals were tested by matrix gene-based rRT-PCR, and influenza virus was detected in 1.5% of sampled pigs, 1.4% of chickens and 1.0% of ducks, but not in pigeons. Full-length genome sequencing confirmed triple reassortant H3N2 in all IAV-positive pigs and various low pathogenic avian influenza subtypes in poultry. Phylogenetic analysis of the swine influenza viruses revealed that these had haemagglutinin and neuraminidase genes originating from human H3N2 viruses previously isolated in South-East Asia. Phylogenetic analysis also revealed that several of the avian influenza subtypes detected were closely related to internal viral genes from highly pathogenic H5N1 and H9N2 formerly sequenced in the region. High sequence homology was likewise found with influenza A viruses circulating in pigs, poultry and wild birds in China and Vietnam, suggesting transboundary introduction and cocirculation of the various influenza subtypes. In conclusion, highly pathogenic subtypes of influenza virus seem rare in backyard poultry, but virus reassortment, involving potentially zoonotic and pandemic subtypes, appears to occur frequently in smallholder pigs and poultry. Increased targeted surveillance and monitoring of influenza circulation on smallholdings would further improve understanding of the transmission dynamics and evolution of influenza viruses in humans, pigs and poultry in the Mekong subregion and could contribute to limit the influenza burden.

  17. Genetic analysis of novel avian A(H7N9) influenza viruses isolated from patients in China, February to April 2013.

    PubMed

    Kageyama, T; Fujisaki, S; Takashita, E; Xu, H; Yamada, S; Uchida, Y; Neumann, G; Saito, T; Kawaoka, Y; Tashiro, M

    2013-04-11

    Novel influenza viruses of the H7N9 subtype have infected 33 and killed nine people in China as of 10 April 2013. Their haemagglutinin (HA) and neuraminidase genes probably originated from Eurasian avian influenza viruses; the remaining genes are closely related to avian H9N2 influenza viruses. Several characteristic amino acid changes in HA and the PB2 RNA polymerase subunit probably facilitate binding to human-type receptors and efficient replication in mammals, respectively, highlighting the pandemic potential of the novel viruses.

  18. Selecting Viruses for the Seasonal Influenza Vaccine

    MedlinePlus

    ... Past Newsletters Selecting Viruses for the Seasonal Influenza Vaccine Language: English Español Recommend on Facebook Tweet ... influence which viruses are selected for use in vaccine production? The influenza viruses in the seasonal flu ...

  19. 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. ...

  20. 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

  1. 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...

  2. 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

  3. 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.

  4. Transmission of Eurasian avian H2 influenza virus to shorebirds in North America.

    PubMed

    Makarova, N V; Kaverin, N V; Krauss, S; Senne, D; Webster, R G

    1999-12-01

    Influenza A virus of the H2 subtype caused a serious pandemic in 1957 and may cause similar outbreaks in the future. To assess the evolution and the antigenic relationships of avian influenza H2 viruses, we sequenced the haemagglutinin (HA) genes of H2 isolates from shorebirds, ducks and poultry in North America and derived a phylogenetic tree to establish their interrelationships. This analysis confirmed the divergence of H2 HA into two geographical lineages, American and Eurasian. One group of viruses isolated from shorebirds in North America had HA belonging to the Eurasian lineage, indicating an interregional transmission of the H2 gene. Characterization of HA with a monoclonal antibody panel revealed that the antigenicity of the Delaware strains differed from the other avian strains analysed. The data emphasizes the importance of avian influenza surveillance.

  5. Household Transmission of Influenza Virus.

    PubMed

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

    2016-02-01

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

  6. 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.

  7. 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.

  8. 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...

  9. Serological behaviour of influenza viruses

    PubMed Central

    Fiset, P.; Depoux, R.

    1954-01-01

    By antibody absorption it was found that strains of influenza virus exhibiting P-Q differences were related according to certain patterns. In the course of this investigation it was also revealed that some viruses possessed masked antigens capable of stimulating antibody production but incapable of combining efficiently with antibody. PMID:14364182

  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. Stimulation of cytotoxic T cells by liposomes containing influenza virus or its components.

    PubMed Central

    Hackett, C J; Taylor, P M; Askonas, B A

    1983-01-01

    Since inactivated virus preparations are poor inducers of influenza-specific cytotoxic T cells (Tc), studies were undertaken utilizing artificial vesicles (liposomes) as a means of delivering viral and H-2 antigens in a multivalent form and oriented with respect to a lipid bilayer. Liposomes prepared from extracted mouse cell lipids efficiently incorporated influenza-viral proteins and were not toxic in culture. Using polybrene to promote greater contact of liposomes with cells, liposomes prepared from whole virus could effectively stimulate memory Tc from spleens of intranasally infected mice in vitro. H-2 was not required in the liposomes to obtain stimulation, and its presence did not improve responses, which were always lower than in parallel stimulations using virally infected syngeneic cells. Liposomes prepared from purified influenza virion subunits (haemagglutinin, neuraminidase, matrix protein) were only slightly stimulatory in vitro, and were unable to prime mice for significant Tc memory. PMID:6602089

  12. Emergence of canine distemper virus strains with two amino acid substitutions in the haemagglutinin protein, detected from vaccinated carnivores in North-Eastern China in 2012-2013.

    PubMed

    Zhao, Jianjun; Zhang, Hailing; Bai, Xue; Martella, Vito; Hu, Bo; Sun, Yangang; Zhu, Chunsheng; Zhang, Lei; Liu, Hao; Xu, Shujuan; Shao, Xiqun; Wu, Wei; Yan, Xijun

    2014-04-01

    A total of 16 strains of canine distemper virus (CDV) were detected from vaccinated minks, foxes, and raccoon dogs in four provinces in North-Eastern China between the end of 2011 and 2013. Upon sequence analysis of the haemagglutinin gene and comparison with wild-type CDV from different species in the same geographical areas, two non-synonymous single nucleotide polymorphisms were identified in 10 CDV strains, which led to amino acid changes at positions 542 (isoleucine to asparagine) and 549 (tyrosine to histidine) of the haemagglutinin protein coding sequence. The change at residue 542 generated a potentially novel N-glycosylation site. Masking of antigenic epitopes by sugar moieties might represent a mechanism for evasion of virus neutralising antibodies and reduced protection by vaccination.

  13. 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.

  14. 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.

  15. 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.

  16. Antigenic and genetic analyses of H1N1 influenza A viruses from European pigs.

    PubMed

    Brown, I H; Ludwig, S; Olsen, C W; Hannoun, C; Scholtissek, C; Hinshaw, V S; Harris, P A; McCauley, J W; Strong, I; Alexander, D J

    1997-03-01

    H1N1 influenza A viruses isolated from pigs in Europe since 1981 were examined both antigenically and genetically and compared with H1N1 viruses from other sources. H1N1 viruses from pigs and birds could be divided into three groups: avian, classical swine and 'avian-like' swine viruses. Low or no reactivity of 'avian-like' swine viruses in HI tests with monoclonal antibodies raised against classical swine viruses was associated with amino acid substitutions within antigenic sites of the haemagglutinin (HA). Phylogenetic analysis of the HA gene revealed that classical swine viruses from European pigs are most similar to each other and are closely related to North American swine strains, whilst the 'avian-like' swine viruses cluster with avian viruses. 'Avian-like' viruses introduced into pigs in the UK in 1992 apparently originated directly from strains in pigs in continental Europe at that time. The HA genes of the swine viruses examined had undergone limited variation in antigenic sites and also contained fewer potential glycosylation sites compared to human H1N1 viruses. The HA exhibited antigenic drift which was more marked in 'avian-like' swine viruses than in classical swine strains. Genetic analyses of two recent 'avian-like' swine viruses indicated that all the RNA segments are related most closely to those of avian influenza A viruses.

  17. Avian influenza virus RNA extraction.

    PubMed

    Spackman, Erica; Lee, Scott A

    2014-01-01

    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 experimentally infected birds. Samples can generally be divided into two types; enriched (e.g. virus stocks) and clinical. Clinical type samples, which may be tissues or swab material, are the most difficult to process due to the complex sample composition and possibly low virus titers. In this chapter two well established procedures for the isolation of AI virus RNA from common clinical specimen types and enriched virus stocks for further molecular applications will be presented.

  18. Development of high-yield influenza B virus vaccine viruses.

    PubMed

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

    2016-12-20

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

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

    PubMed Central

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

    2015-01-01

    Bats are likely natural hosts for a range of zoonotic viruses such as Marburg, Ebola, Rabies, as well as for various Corona- and Paramyxoviruses. In 2009/10, researchers discovered RNA of two novel influenza virus subtypes – H17N10 and H18N11 – in Central and South American fruit bats. The identification of bats as possible additional reservoir for influenza A viruses raises questions about the role of this mammalian taxon in influenza A virus ecology and possible public health relevance. As molecular testing can be limited by a short time window in which the virus is present, serological testing provides information about past infections and virus spread in populations after the virus has been cleared. This study aimed at screening available sera from 100 free-ranging, frugivorous bats (Eidolon helvum) sampled in 2009/10 in Ghana, for the presence of antibodies against the complete panel of influenza A haemagglutinin (HA) types ranging from H1 to H18 by means of a protein microarray platform. This technique enables simultaneous serological testing against multiple recombinant HA-types in 5μl of serum. Preliminary results indicate serological evidence against avian influenza subtype H9 in about 30% of the animals screened, with low-level cross-reactivity to phylogenetically closely related subtypes H8 and H12. To our knowledge, this is the first report of serological evidence of influenza A viruses other than H17 and H18 in bats. As avian influenza subtype H9 is associated with human infections, the implications of our findings from a public health context remain to be investigated. PMID:25965069

  20. 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

  1. 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

  2. Evolution and ecology of influenza A viruses.

    PubMed

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

    1992-03-01

    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

  3. Initial incursion of pandemic (H1N1) 2009 influenza A virus into European pigs.

    PubMed

    Welsh, M D; Baird, P M; Guelbenzu-Gonzalo, M P; Hanna, A; Reid, S M; Essen, S; Russell, C; Thomas, S; Barrass, L; McNeilly, F; McKillen, J; Todd, D; Harkin, V; McDowell, S; Choudhury, B; Irvine, R M; Borobia, J; Grant, J; Brown, I H

    2010-05-22

    The initial incursion of pandemic (H1N1) 2009 influenza A virus (pH1N1) into a European pig population is reported. Diagnosis of swine influenza caused by pandemic virus was made during September 2009 following routine submission of samples for differential diagnosis of causative agents of respiratory disease, including influenza A virus. All four pigs (aged six weeks) submitted for investigation from a pig herd of approximately 5000 animals in Northern Ireland, experiencing acute-onset respiratory signs in finishing and growing pigs, were positive by immunofluorescence for influenza A. Follow-up analysis of lung tissue homogenates by real-time RT-PCR confirmed the presence of pH1N1. The virus was subsequently detected on two other premises in Northern Ireland; on one premises, detection followed the pre-export health certification testing of samples from pigs presumed to be subclinically infected as no clinical signs were apparent. None of the premises was linked to another epidemiologically. Sequencing of the haemagglutinin and neuraminidase genes revealed high nucleotide identity (>99.4 per cent) with other pH1N1s isolated from human beings. Genotypic analyses revealed all gene segments to be most closely related to those of contemporary pH1N1 viruses in human beings. It is concluded that all three outbreaks occurred independently, potentially as a result of transmission of the virus from human beings to pigs.

  4. Evidence of an absence: the genetic origins of the 1918 pandemic influenza virus.

    PubMed

    Reid, Ann H; Taubenberger, Jeffery K; Fanning, Thomas G

    2004-11-01

    Annual outbreaks of influenza A infection are an ongoing public health threat and novel influenza strains can periodically emerge to which humans have little immunity, resulting in devastating pandemics. The 1918 pandemic killed at least 40 million people worldwide and pandemics in 1957 and 1968 caused hundreds of thousands of deaths. The influenza A virus is capable of enormous genetic variation, both by continuous, gradual mutation and by reassortment of genome segments between viruses. Both the 1957 and 1968 pandemic strains are thought to have originated as reassortants in which one or both human-adapted viral surface proteins were replaced by proteins from avian influenza strains. Analyses of the genes of the 1918 pandemic virus, however, indicate that this strain might have had a different origin. The haemagglutinin and nucleoprotein genome segments in particular are unlikely to have come directly from an avian source that is similar to those that are currently being sequenced. Determining whether a pandemic influenza virus can emerge by different mechanisms will affect the scope and focus of surveillance and prevention efforts.

  5. The Optimisation of Pseudotyped Viruses for the Characterisation of Immune Responses to Equine Influenza Virus

    PubMed Central

    Scott, Simon D.; Kinsley, Rebecca; Temperton, Nigel; Daly, Janet M.

    2016-01-01

    Pseudotyped viruses (PVs) produced by co-transfecting cells with plasmids expressing lentiviral core proteins and viral envelope proteins are potentially powerful tools for studying various aspects of equine influenza virus (EIV) biology. The aim of this study was to optimise production of equine influenza PVs. Co-transfection of the HAT protease to activate the haemagglutinin (HA) yielded a higher titre PV than TMPRSS2 with the HA from A/equine/Richmond/1/2007 (H3N8), whereas for A/equine/Newmarket/79 (H3N8), both proteases resulted in equivalent titres. TMPRSS4 was ineffective with the HA of either strain. There was also an inverse relationship between the amount of protease-expression plasmids and the PV titre obtained.  Interestingly, the PV titre obtained by co-transfection of a plasmid encoding the cognate N8 NA was not as high as that generated by the addition of exogenous neuraminidase (NA) from Clostridium perfringens to allow the release of nascent PV particles. Finally, initial characterisation of the reliability of PV neutralisation tests (PVNTs) demonstrated good intra-laboratory repeatability. In conclusion, we have demonstrated that equine influenza PV production can be readily optimised to provide a flexible tool for studying EIV. PMID:27983716

  6. The cytoplasmic tail of the influenza C virus glycoprotein HEF negatively affects transport to the cell surface.

    PubMed

    Oeffner, F; Klenk, H D; Herrler, G

    1999-02-01

    The surface glycoprotein, HEF, of influenza C virus (C/Johannesburg/1/66) has been shown to undergo a post-translation conformational change that is evident in a dramatic change of electrophoretic mobility. If the corresponding gene is expressed in the absence of other viral proteins, this folding process does not occur at all or only very inefficiently. A chimaeric protein, HEF-HA(Tail), in which the short cytoplasmic tail (Arg-Thr-Lys) of HEF was replaced by the cytoplasmic tail of the haemagglutinin of an influenza A virus (fowl plague virus) was constructed. In contrast to the wild-type protein, the chimaeric protein was detected on the cell surface. No further improvement of the surface expression was observed when both the transmembrane domain and the cytoplasmic tail were replaced by the corresponding domains of either the influenza A haemagglutinin or gp40, an endogenous protein of MDCK cells. For the HEF-HA(Tail) construct this study shows that a substantial amount of the protein is converted to the 100 kDa mature form that is observed in virus-infected cells. The HEF-HA expressed on the cell surface reacted positively in esterase and haemadsorption assays, indicating that it was present in a biologically active form. The results show that the short cytoplasmic tail of HEF has a negative effect on the folding and surface transport of this protein. How this effect may be prevented during a virus infection is discussed.

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

    PubMed Central

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

    2016-01-01

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

  8. 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

  9. Unusual influenza A viruses in bats.

    PubMed

    Mehle, Andrew

    2014-09-17

    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.

  10. Glyconanoparticles for the plasmonic detection and discrimination between human and avian influenza virus.

    PubMed

    Marín, María J; Rashid, Abdul; Rejzek, Martin; Fairhurst, Shirley A; Wharton, Stephen A; Martin, Stephen R; McCauley, John W; Wileman, Thomas; Field, Robert A; Russell, David A

    2013-11-07

    A plasmonic bioassay for the specific detection of human influenza virus has been developed based on gold nanoparticles functionalised with a designed and synthesised thiolated trivalent α2,6-thio-linked sialic acid derivative. The glyconanoparticles consist of the thiolated trivalent α2,6-thio-linked sialic acid derivative and a thiolated polyethylene glycol (PEG) derivative self-assembled onto the gold surface. Varying ratios of the trivalent α2,6-thio-linked sialic acid ligand and the PEG ligand were used; a ratio of 25:75 was found to be optimum for the detection of human influenza virus X31 (H3N2). In the presence of the influenza virus a solution of the glyconanoparticles aggregate following the binding of the trivalent α2,6-thio-linked sialic acid ligand to the haemagglutinin on the surface of the virus. The aggregation of the glycoparticles with the influenza virus induces a colour change of the solution within 30 min. Non-purified influenza virus in allantoic fluid was successfully detected using the functionalised glyconanoparticles. A comparison between the trivalent and a monovalent α2,6-thio-linked sialic acid functionalised nanoparticles confirmed that more rapid results, with greater sensitivity, were achieved using the trivalent ligand for the detection of the X31 virus. Importantly, the glyconanoparticles were able to discriminate between human (α2,6 binding) and avian (α2,3 binding) RG14 (H5N1) influenza virus highlighting the binding specificity of the trivalent α2,6-thio-linked sialic acid ligand.

  11. 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.

  12. 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.

  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. Antigenic relationship between influenza B viruses*

    PubMed Central

    Chakraverty, Pratima

    1971-01-01

    The object of this study was to determine whether antigenic groupings exist among influenza B viruses. Altogether, 22 influenza type B strains isolated during the years 1940-68 were examined by reciprocal haemagglutination-inhibition, strain-specific complement-fixation, and serum neutralization tests with sera produced in ferrets and guinea-pigs. It was found that the strain-specific complement-fixation test was superior for separating influenza B viruses into groups whereas the haemagglutination-inhibition and serum neutralization tests were better for demonstrating similarities. The results obtained with these three immunological techniques confirmed that antigenic variation exists among influenza B viruses, although it is not as clearcut as among influenza A viruses. The results were subjected to numerical taxonomic analysis. Dendrograms and minimum-spanning trees were constructed, using methods based on cluster analysis of similarity coefficients. Four main groups of influenza B viruses were established, although they were all interlinked. The results of this study do not justify the separation of influenza B viruses into subtypes similar to those of influenza A viruses. PMID:5317011

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

    PubMed

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

    2015-07-01

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

  16. Isolation and mutation trend analysis of influenza A virus subtype H9N2 in Egypt

    PubMed Central

    2012-01-01

    Background Avian influenza virus H9N2 is a panzootic pathogen that affects poultry causing mild to moderate respiratory distress but has been associated with high morbidity and considerable mortality. Interspecies transmission of H9N2 from avian species to mammalian hosts does occur. The virus possesses human virus-like receptor specificity and it can infect humans producing flu-like illness. Methods Recently, mild influenza like symptoms were detected in H5N1 vaccinated flocks. Influenza A subtype H9N2 was isolated from the infected flock. The virus evolution was investigated by sequencing the viral genes to screen the possible virus recombination. The viral amino acid sequences from the isolated H9N2 strains were compared to other related sequences from the flu data base that were used to assess the robustness of the mutation trend. Changes in the species-associated amino acid residues or those that enabled virulence to mammals were allocated. Results Phylogenetic analyses of haemagglutinin and neuraminidase genes showed that the recently isolated Egyptian strain belonged to the H9N2 sub-lineage that prevails in Israel. The six internal segments of the isolated virus were found to be derived from the same sub-lineage with no new evidence of reassortment. The results demonstrated conserved genetic and biological constitution of H9N2 viruses in the Middle East. The recently isolated H9N2 virus from chicken in Egypt possessed amino acids that could enable the virus to replicate in mammals and caused severe disease in domestic chickens. Conclusion The study highlights the importance of continuous monitoring of the mutations evolved in avian influenza viruses and its impact on virulence to avian species in addition to its importance in the emergence of new strains with the capacity to be a pandemic candidate. PMID:22925485

  17. 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

  18. Genetic tuning of the novel avian influenza A(H7N9) virus during interspecies transmission, China, 2013.

    PubMed

    Wang, D; Yang, L; Gao, R; Zhang, X; Tan, Y; Wu, A; Zhu, W; Zhou, J; Zou, S; Li, Xiyan; Sun, Y; Zhang, Y; Liu, Y; Liu, T; Xiong, Y; Xu, J; Chen, L; Weng, Y; Qi, X; Guo, J; Li, Xiaodan; Dong, J; Huang, W; Zhang, Y; Dong, L; Zhao, X; Liu, L; Lu, J; Lan, Y; Wei, H; Xin, L; Chen, Y; Xu, C; Chen, T; Zhu, Y; Jiang, T; Feng, Z; Yang, W; Wang, Y; Zhu, H; Guan, Y; Gao, G F; Li, D; Han, J; Wang, S; Wu, G; Shu, Y

    2014-06-26

    A novel avian influenza A(H7N9) virus causing human infection emerged in February 2013 in China. To elucidate the mechanism of interspecies transmission, we compared the signature amino acids of avian influenza A(H7N9) viruses from human and non-human hosts and analysed the reassortants of 146 influenza A(H7N9) viruses with full genome sequences. We propose a genetic tuning procedure with continuous amino acid substitutions and reassorting that mediates host adaptation and interspecies transmission. When the early influenza A(H7N9) virus, containing ancestor haemagglutinin (HA) and neuraminidase (NA) genes similar to A/Shanghai/05 virus, circulated in waterfowl and transmitted to terrestrial poultry, it acquired an NA stalk deletion at amino acid positions 69 to 73. Then, receptor binding preference was tuned to increase the affinity to human-like receptors through HA G186V and Q226L mutations in terrestrial poultry. Additional mammalian adaptations such as PB2 E627K were selected in humans. The continual reassortation between H7N9 and H9N2 viruses resulted in multiple genotypes for further host adaptation. When we analysed a potential association of mutations and reassortants with clinical outcome, only the PB2 E627K mutation slightly increased the case fatality rate. Genetic tuning may create opportunities for further adaptation of influenza A(H7N9) and its potential to cause a pandemic.

  19. A seven-segmented influenza A virus expressing the influenza C virus glycoprotein HEF.

    PubMed

    Gao, Qinshan; Brydon, Edward W A; Palese, Peter

    2008-07-01

    Influenza viruses are classified into three types: A, B, and C. The genomes of A- and B-type influenza viruses consist of eight RNA segments, whereas influenza C viruses only have seven RNAs. Both A and B influenza viruses contain two major surface glycoproteins: the hemagglutinin (HA) and the neuraminidase (NA). Influenza C viruses have only one major surface glycoprotein, HEF (hemagglutinin-esterase fusion). By using reverse genetics, we generated two seven-segmented chimeric influenza viruses. Each possesses six RNA segments from influenza virus A/Puerto Rico/8/34 (PB2, PB1, PA, NP, M, and NS); the seventh RNA segment encodes either the influenza virus C/Johannesburg/1/66 HEF full-length protein or a chimeric protein HEF-Ecto, which consists of the HEF ectodomain and the HA transmembrane and cytoplasmic regions. To facilitate packaging of the heterologous segment, both the HEF and HEF-Ecto coding regions are flanked by HA packaging sequences. When introduced as an eighth segment with the NA packaging sequences, both viruses are able to stably express a green fluorescent protein (GFP) gene, indicating a potential use for these viruses as vaccine vectors to carry foreign antigens. Finally, we show that incorporation of a GFP RNA segment enhances the growth of seven-segmented viruses, indicating that efficient influenza A viral RNA packaging requires the presence of eight RNA segments. These results support a selective mechanism of viral RNA recruitment to the budding site.

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

    PubMed

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

    2001-12-29

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

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

    PubMed Central

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

    2001-01-01

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

  2. 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

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

    PubMed

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

    2016-06-03

    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.

  4. 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

  5. [History of influenza epidemics and discovery of influenza virus].

    PubMed

    Shimizu, K

    1997-10-01

    Influenza epidemics occur almost annually, sometimes taking on a global scale and turning into pandemics. According to Noble, the first clearly recorded epidemic was one that struck Europe in 1173 to 1174. In Japan the first comprehensive review of epidemic records was made by Fujikawa in the early 20th century, who listed 46 epidemics between 862 and 1868. Of the ten pandemics since the 1700s that have been certified by Beveridge nine have struck Japan as well. The human influenza A virus was discovered in 1933 soon after Shope succeeded in isolating swine influenza A virus in 1931. Since the discovery studies in the influenza have made immense progress and have contributed greatly to not only virology but also immunology and molecular biology.

  6. A brief introduction to avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. Methamphetamine Reduces Human Influenza A Virus Replication

    PubMed Central

    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. PMID:23139774

  8. 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.

  9. Environmental role in influenza virus outbreaks.

    PubMed

    Sooryanarain, Harini; Elankumaran, Subbiah

    2015-01-01

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

  10. 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

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

    PubMed

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

    2015-09-01

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

  12. Genetic strategy to prevent influenza virus infections in animals.

    PubMed

    Chen, Jianzhu; Chen, Steve C-Y; Stern, Patrick; Scott, Benjamin B; Lois, Carlos

    2008-02-15

    The natural reservoirs of influenza viruses are aquatic birds. After adaptation, avian viruses can acquire the ability to infect humans and cause severe disease. Because domestic poultry serves as a key link between the natural reservoir of influenza viruses and epidemics and pandemics in human populations, an effective measure to control influenza would be to eliminate or reduce influenza virus infection in domestic poultry. The development and distribution of influenza-resistant poultry represents a proactive strategy for controlling the origin of influenza epidemics and pandemics in both poultry and human populations. Recent developments in RNA interference and transgenesis in birds should facilitate the development of influenza-resistant poultry.

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

    PubMed

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

    2005-07-01

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

  14. Nucleocytoplasmic shuttling of influenza A virus proteins.

    PubMed

    Li, Jing; Yu, Meng; Zheng, Weinan; Liu, Wenjun

    2015-05-22

    Influenza viruses transcribe and replicate their genomes in the nuclei of infected host cells. The viral ribonucleoprotein (vRNP) complex of influenza virus is the essential genetic unit of the virus. The viral proteins play important roles in multiple processes, including virus structural maintenance, mediating nucleocytoplasmic shuttling of the vRNP complex, virus particle assembly, and budding. Nucleocytoplasmic shuttling of viral proteins occurs throughout the entire virus life cycle. This review mainly focuses on matrix protein (M1), nucleoprotein (NP), nonstructural protein (NS1), and nuclear export protein (NEP), summarizing the mechanisms of their nucleocytoplasmic shuttling and the regulation of virus replication through their phosphorylation to further understand the regulation of nucleocytoplasmic shuttling in host adaptation of the viruses.

  15. 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.

  16. 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

  17. Novel human H7N9 influenza virus in China.

    PubMed

    Wang, Chengmin; Luo, Jing; Wang, Jing; Su, Wen; Gao, Shanshan; Zhang, Min; Xie, Li; Ding, Hua; Liu, Shelan; Liu, Xiaodong; Chen, Yu; Jia, Yaxiong; He, Hongxuan

    2014-06-01

    Outbreaks of H7N9 avian influenza in humans in 5 provinces and 2 municipalities of China have reawakened concern that avian influenza viruses may again cross species barriers to infect the human population and thereby initiate a new influenza pandemic. Evolutionary analysis shows that human H7N9 influenza viruses originated from the H9N2, H7N3 and H11N9 avian viruses, and that it is as a novel reassortment influenza virus. This article reviews current knowledge on 11 subtypes of influenza A virus from human which can cause human infections.

  18. 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

  19. Detection of novel influenza A(H1N1) virus by real-time RT-PCR.

    PubMed

    Whiley, David M; Bialasiewicz, Seweryn; Bletchly, Cheryl; Faux, Cassandra E; Harrower, Bruce; Gould, Allan R; Lambert, Stephen B; Nimmo, Graeme R; Nissen, Michael D; Sloots, Theo P

    2009-07-01

    Accurate and rapid diagnosis of novel influenza A(H1N1) infection is critical for minimising further spread through timely implementation of antiviral treatment and other public health based measures. In this study we developed two TaqMan-based reverse transcription PCR (RT-PCR) methods for the detection of novel influenza A(H1N1) virus targeting the haemagglutinin and neuraminidase genes. The assays were validated using 152 clinical respiratory samples, including 61 Influenza A positive samples, collected in Queenland, Australia during the years 2008 to 2009 and a further 12 seasonal H1N1 and H3N2 influenza A isolates collected from years 2000 to 2002. A wildtype swine H1N1 isolate was also tested. RNA from an influenza A(H1N1) virus isolate (Auckland, 2009) was used as a positive control. Overall, the results showed that the RT-PCR methods were suitable for sensitive and specific detection of novel influenza A(H1N1) RNA in human samples.

  20. Influenza at the animal-human interface: a review of the literature for virological evidence of human infection with swine or avian influenza viruses other than A(H5N1).

    PubMed

    Freidl, G S; Meijer, A; de Bruin, E; de Nardi, M; Munoz, O; Capua, I; Breed, A C; Harris, K; Hill, A; Kosmider, R; Banks, J; von Dobschuetz, S; Stark, K; Wieland, B; Stevens, K; van der Werf, S; Enouf, V; van der Meulen, K; Van Reeth, K; Dauphin, G; Koopmans, M

    2014-05-08

    Factors that trigger human infection with animal influenza virus progressing into a pandemic are poorly understood. Within a project developing an evidence-based risk assessment framework for influenza viruses in animals, we conducted a review of the literature for evidence of human infection with animal influenza viruses by diagnostic methods used. The review covering Medline, Embase, SciSearch and CabAbstracts yielded 6,955 articles, of which we retained 89; for influenza A(H5N1) and A(H7N9), the official case counts of t he World Health Organization were used. An additional 30 studies were included by scanning the reference lists. Here, we present the findings for confirmed infections with virological evidence. We found reports of 1,419 naturally infected human cases, of which 648 were associated with avian influenza virus (AIV) A(H5N1), 375 with other AIV subtypes, and 396 with swine influenza virus (SIV). Human cases naturally infected with AIV spanned haemagglutinin subtypes H5, H6, H7, H9 and H10. SIV cases were associated with endemic SIV of H1 and H3 subtype descending from North American and Eurasian SIV lineages and various reassortants thereof. Direct exposure to birds or swine was the most likely source of infection for the cases with available information on exposure.

  1. 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 ...

  2. Simultaneous detection and differentiation of Newcastle disease and avian influenza viruses using oligonucleotide microarrays.

    PubMed

    Wang, Lih-Chiann; Pan, Chu-Hsiang; Severinghaus, Lucia Liu; Liu, Lu-Yuan; Chen, Chi-Tsong; Pu, Chang-En; Huang, Dean; Lir, Jihn-Tsair; Chin, Shih-Chien; Cheng, Ming-Chu; Lee, Shu-Hwae; Wang, Ching-Ho

    2008-03-18

    Newcastle disease (ND) and avian influenza (AI) are two of the most important zoonotic viral diseases of birds throughout the world. These two viruses often have a great impact upon the poultry industry. Both viruses are associated with transmission from wild to domestic birds, and often display similar signs that need to be differentiated. A rapid surveillance among wild and domestic birds is important for early disease detection and intervention, and is the basis for what measures should be taken. The surveillance, thus, should be able to differentiate the diseases and provide a detailed analysis of the virus strains. Here, we described a fast, simultaneous and inexpensive approach to the detection of Newcastle disease virus (NDV) and avian influenza virus (AIV) using oligonucleotide microarrays. The NDV pathotypes and the AIV haemagglutinin subtypes H5 and H7 were determined at the same time. Different probes on a microarray targeting the same gene were implemented in order to encompass the diversified virus strains or provide multiple confirmations of the genotype. This ensures good sensitivity and specificity among divergent viruses. Twenty-four virus isolates and twenty-four various combinations of the viruses were tested in this study. All viruses were successfully detected and typed. The hybridization results on microarrays were clearly identified with the naked eyes, with no further imaging equipment needed. The results demonstrate that the detection and typing of multiple viruses can be performed simultaneously and easily using oligonucleotide microarrays. The proposed method may provide potential for rapid surveillance and differential diagnosis of these two important zoonoses in both wild and domestic birds.

  3. 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.

  4. 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... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are devices...

  5. 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... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are devices...

  6. 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... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are devices...

  7. 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... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are devices...

  8. Evasion of natural killer cells by influenza virus.

    PubMed

    Guo, Hailong; Kumar, Pawan; Malarkannan, Subramaniam

    2011-02-01

    NK cells are important innate immune effectors during influenza virus infection. However, the influenza virus seems able to use several tactics to counter NK cell recognition for immune evasion. In this review, we will summarize and discuss recent advances regarding the understanding of NK cell evasion mechanisms manipulated by the influenza virus to facilitate its rapid replication inside the respiratory epithelial cells.

  9. [Present data on influenza virus isolated from ducks and chickens, and influenza virus C. Anti-influenza drugs].

    PubMed

    Fernández del Campo, José Antonio Cabezas

    2004-01-01

    Present data on influenza virus isolated from ducks and chickens, and influenza virus C. Anti-influenza drugs. Within the broad field of Glycopathology and Glycotherapeutics, research on influenza virus types A, B and C from humans and several bird species (particularly migratory birds such as ducks, since they are reservoirs for viruses), as well as the search for improved drugs designed for the prevention or treatment of epidemics/pandemics produced by most of those viruses are issues of relevant interest not only from a scientific point of view but also for repercussions on health and the important economical consequences. The research work begun by the author and collaborators at the Department of Biochemistry and Molecular Biology of the University of Salamanca (Spain) in the middle of the 1970's, developed later in close cooperation with the "(Unité d'Ecologie Virale" of the Pasteur Institute of Paris (Prof. Claude Hannoun and collaborators), has been published in about twenty papers that mainly focus on the theoretic-experimental study of: The sialidase (neuraminidase) activity of human influenza viruses types A and B. The acetylesterase activity of type C virus from humans and dogs. The sialidase activity of type A virus from ducks and pigs, in comparison with that of humans. Certain sialidase inhibitors as useful anti-influenza drugs, especially in the case of possible future influenza pandemics of avian origin.

  10. Influenza and Other Respiratory Viruses in Three Central American Countries

    DTIC Science & Technology

    2010-01-01

    herpes simplex virus in college students. Pediatr Infect Dis J 1993; 12(4):280–284. Laguna-Torres et al. 12 ª 2010 Blackwell Publishing Ltd, Influenza and Other Respiratory Viruses ...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...the identification of adenovirus- es, influenza A virus, influenza B virus, PIVs (types 1, 2, and 3), and RSV. The D3 DFA Herpes Simplex Virus

  11. 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

    2015-01-09

    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.

  12. 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.

  13. 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.

  14. 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

  15. [Transmissibility and pathogenicity of influenza viruses].

    PubMed

    Horimoto, Taisuke; Yamada, Shinya; Kawaoka, Yoshihiro

    2010-09-01

    In the spring of 2009, a novel swine-origin H1N1 virus, whose antigenicity is quite different from those of seasonal human H1N1 strains, emerged in Mexico and readily transmitted and spread among humans, resulting in the first influenza pandemic in the 21st century. Molecular analyses of the pandemic H1N1 2009 viruses indicate low-pathogenic features for humans, although worldwide transmission of the virus and a considerable numbers of lethal cases with acute pneumonia have been observed in the first wave of the current pandemic. Here, we review our current molecular knowledge of transmissibility and pathogenicity of influenza viruses and discuss the future aspects of the pandemic virus.

  16. Quantifying the impact of immune escape on transmission dynamics of influenza.

    PubMed

    Park, Andrew W; Daly, Janet M; Lewis, Nicola S; Smith, Derek J; Wood, James L N; Grenfell, Bryan T

    2009-10-30

    Influenza virus evades prevailing natural and vaccine-induced immunity by accumulating antigenic change in the haemagglutinin surface protein. Linking amino acid substitutions in haemagglutinin epitopes to epidemiology has been problematic because of the scarcity of data connecting these scales. We use experiments on equine influenza virus to address this issue, quantifying how key parameters of viral establishment and shedding increase the probability of transmission with genetic distance between previously immunizing virus and challenge virus. Qualitatively similar patterns emerge from analyses based on antigenic distance and from a published human influenza study. Combination of the equine data and epidemiological models allows us to calculate the effective reproductive number of transmission as a function of relevant genetic change in the virus, illuminating the probability of influenza epidemics as a function of immunity.

  17. Antigenicity and transmissibility of a novel clade 2.3.2.1 avian influenza H5N1 virus.

    PubMed

    Xu, Lili; Bao, Linlin; Yuan, Jing; Li, Fengdi; Lv, Qi; Deng, Wei; Xu, Yanfeng; Yao, Yanfeng; Yu, Pin; Chen, Honglin; Yuen, Kwok-Yung; Qin, Chuan

    2013-12-01

    A genetic variant of the H5N1 influenza virus, termed subclade 2.3.2.1, was first identified in Bulgaria in 2010 and has subsequently been found in Vietnam and Laos. Several cases of human infections with this virus have been identified. Thus, it is important to understand the antigenic properties and transmissibility of this variant. Our results showed that, although it is phylogenetically closely related to other previously characterized clade 2.3 viruses, this novel 2.3.2.1 variant exhibited distinct antigenic properties and showed little cross-reactivity to sera raised against other H5N1 viruses. Like other H5N1 viruses, this variant bound preferentially to avian-type receptors, but contained substitutions at positions 190 and 158 of the haemagglutinin (HA) protein that have been postulated to facilitate HA binding to human-type receptors and to enhance viral transmissibility among mammals, respectively. However, this virus did not appear to have acquired the capacity for airborne transmission between ferrets. These findings highlight the challenges in selecting vaccine candidates for H5N1 influenza because these viruses continue to evolve rapidly in the field. It is important to note that some variants have obtained mutations that may gain transmissibility between model animals, and close surveillance of H5N1 viruses in poultry is warranted.

  18. Seasonal and pandemic human influenza viruses attach better to human upper respiratory tract epithelium than avian influenza viruses.

    PubMed

    van Riel, Debby; den Bakker, Michael A; Leijten, Lonneke M E; Chutinimitkul, Salin; Munster, Vincent J; de Wit, Emmie; Rimmelzwaan, Guus F; Fouchier, Ron A M; Osterhaus, Albert D M E; Kuiken, Thijs

    2010-04-01

    Influenza viruses vary markedly in their efficiency of human-to-human transmission. This variation has been speculated to be determined in part by the tropism of influenza virus for the human upper respiratory tract. To study this tropism, we determined the pattern of virus attachment by virus histochemistry of three human and three avian influenza viruses in human nasal septum, conchae, nasopharynx, paranasal sinuses, and larynx. We found that the human influenza viruses-two seasonal influenza viruses and pandemic H1N1 virus-attached abundantly to ciliated epithelial cells and goblet cells throughout the upper respiratory tract. In contrast, the avian influenza viruses, including the highly pathogenic H5N1 virus, attached only rarely to epithelial cells or goblet cells. Both human and avian viruses attached occasionally to cells of the submucosal glands. The pattern of virus attachment was similar among the different sites of the human upper respiratory tract for each virus tested. We conclude that influenza viruses that are transmitted efficiently among humans attach abundantly to human upper respiratory tract, whereas inefficiently transmitted influenza viruses attach rarely. These results suggest that the ability of an influenza virus to attach to human upper respiratory tract is a critical factor for efficient transmission in the human population.

  19. Trichoplusia ni cells (High Five™) are highly efficient for the production of influenza A virus-like particles: a comparison of two insect cell lines as production platforms for influenza vaccines

    PubMed Central

    Krammer, Florian; Schinko, Theresa; Palmberger, Dieter; Tauer, Christopher; Messner, Paul; Grabherr, Reingard

    2015-01-01

    Virus-like particles (VLPs) consisting of the influenza A virus proteins haemagglutinin (HA) and matrix protein (M1) represent a new alternative approach for vaccine design against influenza virus. Influenza VLPs can be fast and easily produced in sufficient amounts in insect cells using the baculovirus expression system. Up to now, influenza VLPs have been produced in the Spodoptera frugiperda cell line Sf9. We compared VLP production in terms of yield and quality in two insect cell lines, namely Sf9 and the Trichoplusia ni cell line BTI-TN5B1-4 (High Five™). Additionally we compared VLP production with three different HAs and two different M1s from influenza H1 and H3 strains including one swine-origin pandemic H1N1 strain. Comparison of the two cell lines showed dramatic differences in baculovirus background as well as in yield and particle density. Taken together, we consider the establishment of the BTI-TN5B1-4 cell line advantageous as production cell line for influenza VLPs. PMID:20300881

  20. H7N9 influenza viruses interact preferentially with α2,3-linked sialic acids and bind weakly to α2,6-linked sialic acids.

    PubMed

    Ramos, Irene; Krammer, Florian; Hai, Rong; Aguilera, Domingo; Bernal-Rubio, Dabeiba; Steel, John; García-Sastre, Adolfo; Fernandez-Sesma, Ana

    2013-11-01

    The recent human outbreak of H7N9 avian influenza A virus has caused worldwide concerns. Receptor binding specificity is critical for viral pathogenicity, and still not thoroughly studied for this emerging virus. Here, we evaluated the receptor specificity of the haemagglutinin (HA) of two human H7N9 isolates (A/Shanghai/1/13 and A/Anhui/1/13) through a solid-phase binding assay and a flow cytometry-based assay. In addition, we compared it with those from several HAs from human and avian influenza viruses. We observed that the HAs from the novel H7 isolates strongly interacted with α2,3-linked sialic acids. Importantly, they also showed low levels of binding to α2,6-linked sialic acids, but significantly higher than other avian H7s.

  1. 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.

  2. 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...

  3. Influenza virus infection in guinea pigs raised as livestock, Ecuador.

    PubMed

    Leyva-Grado, Victor H; Mubareka, Samira; Krammer, Florian; Cárdenas, Washington B; Palese, Peter

    2012-07-01

    To determine whether guinea pigs are infected with influenza virus in nature, we conducted a serologic study in domestic guinea pigs in Ecuador. Detection of antibodies against influenza A and B raises the question about the role of guinea pigs in the ecology and epidemiology of influenza virus in the region.

  4. [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.

  5. 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.

  6. 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

  7. 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.

  8. FUNCTION OF SIALIDASE IN INFLUENZA VIRUSES.

    DTIC Science & Technology

    In order to investigate the function of sialidase during influenza virus multiplication, methods were developed to isolate and purify the enzyme...of sialidases from myxoviruses best characterized the enzyme. This was accomplished by preparing highly specific enzyme antisera. The specific

  9. 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.

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

    MedlinePlus

    ... or prolonged contact with sick or dead infected poultry. Infected birds shed avian influenza virus in their ... known to have occurred. People who work with poultry or who respond to avian influenza outbreaks are ...

  11. Avian influenza virus infections in humans.

    PubMed

    Wong, Samson S Y; Yuen, Kwok-Yung

    2006-01-01

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

  12. Serological evidence for exposure to avian influenza viruses within poultry workers in southern China.

    PubMed

    de Bruin, E; Zhang, X; Ke, C; Sikkema, R; Koopmans, M

    2017-02-20

    The risk of infection with avian influenza viruses for poultry workers is relatively unknown in China, and study results are often biased by the notification of only the severe human cases. Protein microarray was used to detect binding antibodies to 13 different haemagglutinin (HA1-part) antigens of avian influenza A(H5N1), A(H7N7), A(H7N9) and A(H9N2) viruses, in serum samples from poultry workers and healthy blood donors collected in the course of 3 years in Guangdong Province, China. Significantly higher antibody titre levels were detected in poultry workers when compared to blood donors for the most recent H5 and H9 strains tested. These differences were most pronounced in younger age groups for antigens from older strains, but were observed in all age groups for the recent H5 and H9 antigens. For the H7 strains tested, only poultry workers from two retail live poultry markets had significantly higher antibody titres compared to blood donors.

  13. Implications of global and regional patterns of highly pathogenic avian influenza virus H5N1 clades for risk management.

    PubMed

    Pfeiffer, Dirk U; Otte, Martin J; Roland-Holst, David; Inui, Ken; Nguyen, Tung; Zilberman, David

    2011-12-01

    This paper analyses the publicly available data on the distribution and evolution of highly pathogenic avian influenza virus (HPAIV) H5N1 clades, whilst acknowledging the biases resulting from the non-random selection of isolates for gene sequencing. The data indicate molecular heterogeneity in the global distribution of HPAIV H5N1, in particular in different parts of East and Southeast Asia. Analysis of the temporal pattern of haemagglutinin clade data shows a progression from clade 0 (the 'dominant' clade between 1996 and 2002) to clade 1 (2003-2005) and then to clade 2.3.4 (2005 onwards). This process continuously produces variants, depending on the frequency of virus multiplication in the host population, which is influenced by geographical variation in poultry density, poultry production systems and also HPAI risk management measures such as vaccination. Increased multilateral collaboration needs to focus on developing enhanced disease surveillance and control targeted at evolutionary 'hotspots'.

  14. 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.

  15. Nucleic acid-based detection of influenza A virus subtypes H7 and N9 with a special emphasis on the avian H7N9 virus.

    PubMed

    Kalthoff, D; Bogs, J; Harder, T; Grund, C; Pohlmann, A; Beer, M; Hoffmann, B

    2014-03-13

    In 2013, a novel influenza A virus of subtype H7N9 was transmitted from avian sources to humans in China, causing severe illness and substantial mortality. Rapid and sensitive diagnostic approaches are the basis of epidemiological studies and of utmost importance for the detection of infected humans and animals. We developed various quantitative reverse transcriptase PCR (RT-qPCR) assays for (i) the generic detection of the haemagglutinin (HA) gene of H7 viruses or the neuraminidase (NA) gene of N9 viruses, and (ii) the specific detection of HA and NA of the novel avian H7N9/2013 virus. The sensitivity of the newly developed assays was compared with previously published PCRs, and the specificity of all RT-qPCRs was examined using a panel of 42 different H7 and 16 different N9 isolates. Furthermore, we analysed the performance of the RT-qPCR assays with dilution series and diagnostic samples obtained from animal experiments. Our study provides a comprehensive set of RT-qPCR assays for the reliable detection of the novel avian H7N9 virus, with high sensitivity and improved and tailored specificity values compared with published assays. Finally, we also present data about the robustness of a duplex assay for the simultaneous detection of HA and NA of the avian influenza H7N9/2013 virus.

  16. Identification of Virulence Determinants in Influenza Viruses

    PubMed Central

    2015-01-01

    To date there is no rapid method to screen for highly pathogenic avian influenza strains that may be indicators of future pandemics. We report here the first development of an oligonucleotide-based spectroscopic assay to rapidly and sensitively detect a N66S mutation in the gene coding for the PB1-F2 protein associated with increased virulence in highly pathogenic pandemic influenza viruses. 5′-Thiolated ssDNA oligonucleotides were employed as probes to capture RNA isolated from six influenza viruses, three having N66S mutations, two without the N66S mutation, and one deletion mutant not encoding the PB1-F2 protein. Hybridization was detected without amplification or labeling using the intrinsic surfaced-enhanced Raman spectrum of the DNA-RNA complex. Multivariate analysis identified target RNA binding from noncomplementary sequences with 100% sensitivity, 100% selectivity, and 100% correct classification in the test data set. These results establish that optical-based diagnostic methods are able to directly identify diagnostic indicators of virulence linked to highly pathogenic pandemic influenza viruses without amplification or labeling. PMID:24937567

  17. 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.

  18. 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

  19. Transmission of influenza B viruses in the guinea pig.

    PubMed

    Pica, Natalie; Chou, Yi-Ying; Bouvier, Nicole M; Palese, Peter

    2012-04-01

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

  20. 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...

  1. 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... virus serological reagents. (a) Identification. Influenza virus serological reagents are devices...

  2. 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.

  3. 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

  4. Avian influenza A H5N1 virus.

    PubMed

    Loeffelholz, Michael J

    2010-03-01

    Although influenza A viruses of avian origin have long been responsible for influenza pandemics, including the "Spanish flu" pandemic of 1918, human infections caused by avian subtypes of influenza A virus, most notably H5N1, have emerged since the 1990s (H5N1 in 1997; H9N2 in 1999; and H7N7 in 2003). The wide geographic distribution of influenza A H5N1 in avian species, and the number and severity of human infections are unprecedented. Together with the ongoing genetic evolution of this virus, these features make influenza A H5N1 a likely candidate for a future influenza pandemic. This article discusses the epidemiology, pathogenesis, and diagnosis of human infections caused by influenza A H5N1 virus.

  5. Thermal denaturation of influenza virus and its relationship to membrane fusion.

    PubMed Central

    Epand, Richard M; Epand, Raquel F

    2002-01-01

    The X-31 strain of influenza virus was studied by differential scanning calorimetry (DSC), CD and SDS/PAGE analysis as a function of both temperature and pH. A bromelain-treated virus was also studied by these methods. The major transition observed in the intact virus was a result of the denaturation of the haemagglutinin (HA) protein. At pH 7.4, this transition was similar in the intact virus and the isolated HA, but was absent in the bromelain-treated virus. However, at pH 5 the denaturation temperature and enthalpy were both higher for HA in the virus than in the isolated protein, indicating that HA interacts with other molecular components in the intact virus. The transition observed by DSC occurs at a higher temperature than does the thermal transition observed by CD. The temperature of the CD transition coincides with the temperature at which the fusogenicity of the virus increases, and probably corresponds to the formation of an extended coiled-coil conformation. Analysis by SDS/PAGE at neutral pH under non-reducing conditions demonstrates a selective loss of the HA protein trimer, resulting in the formation of aggregates in the range of temperatures of 55 to 70 degrees C. In contrast, at acidic pH, the HA protein is largely in the monomeric form at 25 degrees C, and there is little change with temperature. There is thus a weakening of the quaternary structure of HA at acidic pH prior to heating. At the temperature at which the virus exhibits an increased fusogenicity at neutral pH, there is a loss of secondary structure and a beginning of a destabilization of the trimeric form of HA. This temperature is lower than that required for the major endothermic peak observed in DSC experiments. The results demonstrate that there is no kinetically trapped high-energy form of HA at neutral pH. PMID:11994048

  6. Assessing the development of oseltamivir and zanamivir resistance in A(H5N1) influenza viruses using a ferret model.

    PubMed

    Hurt, Aeron C; Lowther, Sue; Middleton, Deborah; Barr, Ian G

    2010-09-01

    Using an in vivo ferret model, we investigated the development of resistance to oseltamivir and zanamivir for two different influenza A(H5N1) viruses (A/Vietnam/1203/2004, haemagglutinin phylogenetic clade 1, and A/Chicken/Laos/26/2006, haemagglutinin phylogenetic clade 2.3) by treating the animals with doses equivalent either to the recommended human treatment dose or a range of sub-optimal drug doses. No resistance was observed in oseltamivir-treated ferrets, but analysis of nasal washes from zanamivir-treated ferrets infected with influenza A/Vietnam/1203/2004 revealed one viral isolate (from a ferret receiving the highest dose of zanamivir, 1.0mg/kg twice daily) with a zanamivir IC(50) that was 350-fold higher than the other isolates tested. The same virus also demonstrated a 26-fold increase in oseltamivir IC(50). The isolate with reduced susceptibility was taken from a ferret 8 days post-infection that was being treated with the recommended human zanamivir dose. Sequence analysis of the resistant virus revealed a glutamine (Q) to leucine (L) mutation at residue 136 of the neuraminidase. This is the first report of this mutation being associated with neuraminidase inhibitor susceptibility and one of the few reported mutations that confer zanamivir resistance, and as such should be closely monitored in influenza A(H5N1) and other N1 viruses in the future. Further animal studies and human clinical trials are necessary to optimize neuraminidase inhibitor dosing strategies for the treatment of influenza A(H5N1) infections.

  7. 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.

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

    PubMed

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

    2016-04-15

    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.

  9. 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.

  10. 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

  11. Neurologic Complications of Influenza B Virus Infection in Adults, Romania.

    PubMed

    Popescu, Corneliu P; Florescu, Simin A; Lupulescu, Emilia; Zaharia, Mihaela; Tardei, Gratiela; Lazar, Mihaela; Ceausu, Emanoil; Ruta, Simona M

    2017-04-01

    We characterized influenza B virus-related neurologic manifestations in an unusually high number of hospitalized adults at a tertiary care facility in Romania during the 2014-15 influenza epidemic season. Of 32 patients with a confirmed laboratory diagnosis of influenza B virus infection, neurologic complications developed in 7 adults (median age 31 years). These complications were clinically diagnosed as confirmed encephalitis (4 patients), possible encephalitis (2 patients), and cerebellar ataxia (1 patient). Two of the patients died. Virus sequencing identified influenza virus B (Yam)-lineage clade 3, which is representative of the B/Phuket/3073/2013 strain, in 4 patients. None of the patients had been vaccinated against influenza. These results suggest that influenza B virus can cause a severe clinical course and should be considered as an etiologic factor for encephalitis.

  12. 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.

  13. Sialidase, receptor-binding and fusion-promotion activities of Newcastle disease virus haemagglutinin-neuraminidase glycoprotein: a mutational and kinetic study.

    PubMed

    Ferreira, Laura; Muñoz-Barroso, Isabel; Marcos, Fernando; Shnyrov, Valery L; Villar, Enrique

    2004-07-01

    Mutations were generated in residues at the putative catalytic site of the haemagglutinin-neuraminidase (HN) protein of Newcastle disease virus Clone 30 strain (Arg498, Glu258, Tyr262, Tyr317 and Ser418) and their effects on its three associated activities were studied. Expression of the mutant proteins at the surface of HeLa cells was similar to that of the wild-type. Sialidase, receptor-binding and fusion-promotion activities were affected to different degrees for all mutants studied. Mutant Arg498Lys lost most of its sialidase activity, although it retained most of the receptor-binding activity, suggesting that, for the former activity, besides the presence of a basic residue, the proximity to the substrate molecule is also important, as Lys is shorter than Arg. Proximity also seems to be important in substrate recognition, since Tyr262Phe retained most of its sialidase activity while Tyr262Ser lost most of it. Also, Ser418Ala displayed most of the wild-type sialidase activity. However, a kinetic and thermodynamic study of the sialidase activity of the Tyr262Ser and Ser418Ala mutants was performed and revealed that the hydroxyl group of these residues also plays an important role in catalysis, since such activity was much less effective than that of the wild-type and these mutations modified their activation energy for sialidase catalysis. The discrepancy of the modifications in sialidase and receptor-binding activities in the mutants analysed does not account for the topological coincidence of the two sites. These results also suggest that the globular head of HN protein may play a role in fusion-promotion activity.

  14. Phylogenetic analysis of the haemagglutinin gene of canine distemper virus strains detected from breeding foxes, raccoon dogs and minks in China.

    PubMed

    Zhao, Jian-Jun; Yan, Xi-Jun; Chai, Xiu-Li; Martella, Vito; Luo, Guo-Liang; Zhang, Hai-Ling; Gao, Han; Liu, Ying-Xue; Bai, Xue; Zhang, Lei; Chen, Tao; Xu, Lei; Zhao, Chun-Fei; Wang, Feng-Xue; Shao, Xi-Qun; Wu, Wei; Cheng, Shi-Peng

    2010-01-06

    Canine distemper virus (CDV) infects a variety of carnivores, including wild and domestic Canidae. Genetic/antigenic heterogeneity has been observed among the various CDV strains, notably in the haemagglutinin (H) gene, that appears as a good target to gather epidemiological information. Based on sequence analysis of the H gene, wild-type CDV strains cluster into distinct geographic lineages (genotypes), irrespective of the species of isolation. The sequence of the H gene of 28 CDV strains detected from both vaccinated and non-vaccinated breeding foxes, raccoon dogs and minks from different geographical areas of China during the years 2004-2008 was determined. All the CDV strains but two (strains HL and HLJ2) were characterized as Asia-1 genotype and were highly similar to each other (96.2-99.7% at the amino acid [aa] level) and to other Asia-1 strains (96.1-99.5% aa) previously detected in China. The CDV strains HL and HLJ2 were both collected from foxes in Heilongjiang province in 2005. Strain HL resembled CDVs of the Arctic genotype (GR88-like) and displayed high aa identity (98.0%) to the Chinese canine strain Liu. By converse, strain HLJ2 was barely related to CDVs of the Asia-2 genotype (88.7-90.3% aa identity), and could represent a novel CDV genotype, tentatively proposed as Asia-3. These results suggest that at least three different CDV genotypes, distantly related (81.8-91.6% aa identity) to the vaccine strains, Onderstepoort-like (America-1 genotype), are currently circulating in breeding foxes, raccoon dogs and minks in China, and that the genotype Asia-1 is predominant. Whether the diversity between wild-type CDVs and the vaccine strains may affect, to some extent, the efficacy of the vaccines deserves further investigations.

  15. Molecular characterization of partial fusion gene and C-terminus extension length of haemagglutinin-neuraminidase gene of recently isolated Newcastle disease virus isolates in Malaysia

    PubMed Central

    2010-01-01

    Background Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a highly contagious disease of birds and has been one of the major causes of economic losses in the poultry industry. Despite routine vaccination programs, sporadic cases have occasionally occurred in the country and remain a constant threat to commercial poultry. Hence, the present study was aimed to characterize NDV isolates obtained from clinical cases in various locations of Malaysia between 2004 and 2007 based on sequence and phylogenetic analysis of partial F gene and C-terminus extension length of HN gene. Results The coding region of eleven NDV isolates fusion (F) gene and carboxyl terminal region of haemagglutinin-neuraminidase (HN) gene including extensions were amplified by reverse transcriptase PCR and directly sequenced. All the isolates have shown to have non-synonymous to synonymous base substitution rate ranging between 0.081 - 0.264 demonstrating presence of negative selection. Analysis based on F gene showed the characterized isolates possess three different types of protease cleavage site motifs; namely 112RRQKRF117, 112RRRKRF117 and 112GRQGRL117 and appear to show maximum identities with isolates in the region such as cockatoo/14698/90 (Indonesia), Ch/2000 (China), local isolate AF2240 indicating the high similarity of isolates circulating in the South East Asian countries. Meanwhile, one of the isolates resembles commonly used lentogenic vaccine strains. On further characterization of the HN gene, Malaysian isolates had C-terminus extensions of 0, 6 and 11 amino acids. Analysis of the phylogenetic tree revealed that the existence of three genetic groups; namely, genotype II, VII and VIII. Conclusions The study concluded that the occurrence of three types of NDV genotypes and presence of varied carboxyl terminus extension lengths among Malaysian isolates incriminated for sporadic cases. PMID:20691110

  16. 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.

  17. 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.

  18. Characterization of Uncultivable Bat Influenza Virus Using a Replicative Synthetic Virus

    PubMed Central

    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

    2014-01-01

    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. PMID:25275541

  19. 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.

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

    PubMed Central

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

    2014-01-01

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

  1. The origin and virulence of the 1918 "Spanish" influenza virus.

    PubMed

    Taubenberger, Jeffery K

    2006-03-01

    The "Spanish" influenza pandemic of 1918-19 caused acute illness in 25-30 percent of the world's population and resulted in the death of up to an estimated 40 million people. Using fixed and frozen lung tissue of 1918 influenza victims, the complete genomic sequence of the 1918 influenza virus has been deduced. Sequence and phylogenetic analysis of the completed 1918 influenza virus genes shows them to be the most avian-like among the mammalian-adapted viruses. This finding supports the hypotheses that (1) the pandemic virus contains genes derived from avian-like influenza virus strains and that (2) the 1918 virus is the common ancestor of human and classical swine H1N1 influenza viruses. The relationship of the 1918 virus with avian influenza viruses is further supported by recent work in which the 1918 hemagglutinin (HA) protein crystal structure was resolved. Neither the 1918 hemagglutinin (HA) nor the neuraminidase (NA) genes possess mutations known to increase tissue tropicity that account for the virulence of other influenza virus strains like A/WSN/33 or the highly pathogenic avian influenza H5 or H7 viruses. Using reverse genetics approaches, influenza virus constructs containing the 1918 HA and NA on a modern human influenza virus background were lethal in mice. The complete 1918 virus was even more virulent in mice. The genotypic basis of this virulence has not yet been elucidated. The complete sequence of the non-structural (NS) gene segment of the 1918 virus was deduced and also tested for the hypothesis that enhanced virulence in 1918 could have been due to type I interferon inhibition by the NS1 protein. Results from these experiments suggest that in human cells the 1918 NS1 is a very effective interferon antagonist, but the 1918 NS1 gene does not have the amino acid change that correlates with virulence in the H5N1 virus strains identified in 1997 in Hong Kong. Sequence analysis of the 1918 pandemic influenza virus is allowing us to test hypotheses

  2. Characterization of the reconstructed 1918 Spanish influenza pandemic virus.

    PubMed

    Tumpey, Terrence M; Basler, Christopher F; Aguilar, Patricia V; Zeng, Hui; Solórzano, Alicia; Swayne, David E; Cox, Nancy J; Katz, Jacqueline M; Taubenberger, Jeffery K; Palese, Peter; García-Sastre, Adolfo

    2005-10-07

    The pandemic influenza virus of 1918-1919 killed an estimated 20 to 50 million people worldwide. With the recent availability of the complete 1918 influenza virus coding sequence, we used reverse genetics to generate an influenza virus bearing all eight gene segments of the pandemic virus to study the properties associated with its extraordinary virulence. In stark contrast to contemporary human influenza H1N1 viruses, the 1918 pandemic virus had the ability to replicate in the absence of trypsin, caused death in mice and embryonated chicken eggs, and displayed a high-growth phenotype in human bronchial epithelial cells. Moreover, the coordinated expression of the 1918 virus genes most certainly confers the unique high-virulence phenotype observed with this pandemic virus.

  3. 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.

  4. Restoration of virulence of escape mutants of H5 and H9 influenza viruses by their readaptation to mice.

    PubMed

    Rudneva, Irina A; Ilyushina, Natalia A; Timofeeva, Tatiana A; Webster, Robert G; Kaverin, Nikolai V

    2005-10-01

    Antigenic mapping of the haemagglutinin (HA) molecule of H5 and H9 influenza viruses by selecting escape mutants with monoclonal anti-HA antibodies and subjecting the selected viruses to immunological analysis and sequencing has previously been performed. The viruses used as wild-type strains were mouse-adapted variants of the original H5 and H9 isolates. Phenotypic characterization of the escape mutants revealed that the amino acid change in HA that conferred resistance to a monoclonal antibody was sometimes associated with additional effects, including decreased virulence for mice. In the present study, the low-virulence H5 and H9 escape mutants were readapted to mice. Analysis of the readapted variants revealed that the reacquisition of virulence was not necessarily achieved by reacquisition of the wild-type HA gene sequence, but was also associated either with the removal of a glycosylation site (the one acquired previously by the escape mutant) without the exact restoration of the initial wild-type amino acid sequence, or, for an H5 escape mutant that had no newly acquired glycosylation sites, with an additional amino acid change in a remote part of the HA molecule. The data suggest that such 'compensating' mutations, removing the damaging effects of antibody-selected amino acid changes, may be important in the course of influenza virus evolution.

  5. Neurologic Complications of Influenza B Virus Infection in Adults, Romania

    PubMed Central

    Florescu, Simin A.; Lupulescu, Emilia; Zaharia, Mihaela; Tardei, Gratiela; Lazar, Mihaela; Ceausu, Emanoil; Ruta, Simona M.

    2017-01-01

    We characterized influenza B virus–related neurologic manifestations in an unusually high number of hospitalized adults at a tertiary care facility in Romania during the 2014–15 influenza epidemic season. Of 32 patients with a confirmed laboratory diagnosis of influenza B virus infection, neurologic complications developed in 7 adults (median age 31 years). These complications were clinically diagnosed as confirmed encephalitis (4 patients), possible encephalitis (2 patients), and cerebellar ataxia (1 patient). Two of the patients died. Virus sequencing identified influenza virus B (Yam)-lineage clade 3, which is representative of the B/Phuket/3073/2013 strain, in 4 patients. None of the patients had been vaccinated against influenza. These results suggest that influenza B virus can cause a severe clinical course and should be considered as an etiologic factor for encephalitis. PMID:28322689

  6. Pathogenicity of modified bat influenza virus with different M genes and its reassortment potential with swine influenza A virus.

    PubMed

    Yang, Jianmei; Lee, Jinhwa; Ma, Jingjiao; Lang, Yuekun; Nietfeld, Jerome; Li, Yuhao; Duff, Michael; Li, Yonghai; Yang, Yuju; Liu, Haixia; Zhou, Bin; Wentworth, David E; Richt, Juergen A; Li, Zejun; Ma, Wenjun

    2017-01-18

    In our previous studies the reassortant virus containing only the PR8 H1N1 matrix (M) gene in the background of the modified bat influenza Bat09:mH1mN1 virus could be generated. However, whether M genes from other origins can be rescued in the background of the Bat09:mH1mN1 virus and whether the resulting novel reassortant virus is virulent remain unknown. Herein, two reassortant viruses were generated in the background of the Bat09:mH1mN1 virus containing either a North American or a Eurasian swine influenza virus M gene. These two reassortant viruses and the reassortant virus with PR8 M as well as the control Bat09:mH1mN1 virus replicated efficiently in cultured cells, while the reassortant virus with PR8 M grew to a higher titer than the other three viruses in tested cells. Mouse studies showed that reassortant viruses with either North American or Eurasian swine influenza virus M genes did not enhance virulence, whereas the reassortant virus with PR8 M gene displayed higher pathogenicity when compared to the Bat09:mH1mN1 virus. This is most likely due to the fact that the PR8 H1N1 virus is a mouse-adapted virus. Furthermore, reassortment potential between the Bat09:mH1mN1 virus and an H3N2 swine influenza virus (A/swine/Texas/4199-2/1998) was investigated using co-infection of MDCK cells, but no reassortant viruses were detected. Taken together, our results indicate that the modified bat influenza virus is most likely incapable of reassortment with influenza A viruses with in vitro co-infection experiments, although reassortant viruses with different M genes can be generated by reverse genetics.

  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. 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.

  9. 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),...

  10. 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...

  11. 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...

  12. Avian Influenza A (H7N9) Virus

    MedlinePlus

    ... Humans Diagnostics for Detecting H7N9 Using rRT-PCR Infection Control Within Healthcare Settings for Patients with Novel Influenza ... percent of people confirmed with Asian H7N9 virus infection died. Epidemiology Most human infections with avian influenza viruses, including ...

  13. 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...

  14. Low-Pathogenic Avian Influenza Viruses in Wild House Mice

    PubMed Central

    Shriner, Susan A.; VanDalen, Kaci K.; Mooers, Nicole L.; Ellis, Jeremy W.; Sullivan, Heather J.; Root, J. Jeffrey; Pelzel, Angela M.; Franklin, Alan B.

    2012-01-01

    Background Avian influenza viruses are known to productively infect a number of mammal species, several of which are commonly found on or near poultry and gamebird farms. While control of rodent species is often used to limit avian influenza virus transmission within and among outbreak sites, few studies have investigated the potential role of these species in outbreak dynamics. Methodology/Principal Findings We trapped and sampled synanthropic mammals on a gamebird farm in Idaho, USA that had recently experienced a low pathogenic avian influenza outbreak. Six of six house mice (Mus musculus) caught on the outbreak farm were presumptively positive for antibodies to type A influenza. Consequently, we experimentally infected groups of naïve wild-caught house mice with five different low pathogenic avian influenza viruses that included three viruses derived from wild birds and two viruses derived from chickens. Virus replication was efficient in house mice inoculated with viruses derived from wild birds and more moderate for chicken-derived viruses. Mean titers (EID50 equivalents/mL) across all lung samples from seven days of sampling (three mice/day) ranged from 103.89 (H3N6) to 105.06 (H4N6) for the wild bird viruses and 102.08 (H6N2) to 102.85 (H4N8) for the chicken-derived viruses. Interestingly, multiple regression models indicated differential replication between sexes, with significantly (p<0.05) higher concentrations of avian influenza RNA found in females compared with males. Conclusions/Significance Avian influenza viruses replicated efficiently in wild-caught house mice without adaptation, indicating mice may be a risk pathway for movement of avian influenza viruses on poultry and gamebird farms. Differential virus replication between males and females warrants further investigation to determine the generality of this result in avian influenza disease dynamics. PMID:22720076

  15. 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

  16. Influenza A and B Virus Attachment to Respiratory Tract in Marine Mammals

    PubMed Central

    van Riel, Debby; van de Bildt, Marco W.G; Osterhaus, Albert; Kuiken, Thijs

    2012-01-01

    Patterns of virus attachment to the respiratory tract of 4 marine mammal species were determined for avian and human influenza viruses. Attachment of avian influenza A viruses (H4N5) and (H7N7) and human influenza B viruses to trachea and bronchi of harbor seals is consistent with reported influenza outbreaks in this species. PMID:22516350

  17. Immune history and influenza virus susceptibility.

    PubMed

    Cobey, Sarah; Hensley, Scott E

    2017-01-12

    Antibody responses to influenza viruses are critical for protection, but the ways in which repeated viral exposures shape antibody evolution and effectiveness over time remain controversial. Early observations demonstrated that viral exposure history has a profound effect on the specificity and magnitude of antibody responses to a new viral strain, a phenomenon called 'original antigenic sin.' Although 'sin' might suppress some aspects of the immune response, so far there is little indication that hosts with pre-existing immunity are more susceptible to viral infections compared to naïve hosts. However, the tendency of the immune response to focus on previously recognized conserved epitopes when encountering new viral strains can create an opportunity cost when mutations arise in these conserved epitopes. Hosts with different exposure histories may continue to experience distinct patterns of infection over time, which may influence influenza viruses' continued antigenic evolution. Understanding the dynamics of B cell competition that underlie the development of antibody responses might help explain the low effectiveness of current influenza vaccines and lead to better vaccination strategies.

  18. 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.

  19. Pathogenesis of Influenza D Virus in Cattle

    PubMed Central

    Olivier, Alicia K.; Genova, Suzanne; Epperson, William B.; Smith, David R.; Schneider, Liesel; Barton, Kathleen; McCuan, Katlin; Webby, Richard J.

    2016-01-01

    ABSTRACT Cattle have been proposed as the natural reservoir of a novel member of the virus family Orthomyxoviridae, which has been tentatively classified as influenza D virus (IDV). Although isolated from sick animals, it is unclear whether IDV causes any clinical disease in cattle. To address this aspect of Koch's postulates, three dairy calves (treatment animals) held in individual pens were inoculated intranasally with IDV strain D/bovine/Mississippi/C00046N/2014. At 1 day postinoculation, a seronegative calf (contact animal) was added to each of the treatment animal pens. The cattle in both treatment and contact groups seroconverted, and virus was detected in their respiratory tracts. Histologically, there was a significant increase in neutrophil tracking in tracheal epithelia of the treatment calves compared to control animals. While infected and contact animals demonstrated various symptoms of respiratory tract infection, they were mild, and the calves in the treatment group did not differ from the controls in terms of heart rate, respiratory rate, or rectal temperature. To mimic zoonotic transmission, two ferrets were exposed to a plastic toy fomite soaked with infected nasal discharge from the treatment calves. These ferrets did not shed the virus or seroconvert. In summary, this study demonstrates that IDV causes a mild respiratory disease upon experimental infection of cattle and can be transmitted effectively among cattle by in-pen contact, but not from cattle to ferrets through fomite exposure. These findings support the hypothesis that cattle are a natural reservoir for the virus. IMPORTANCE A novel influenza virus, tentatively classified as influenza D virus (IDV), was identified in swine, cattle, sheep, and goats. Among these hosts, cattle have been proposed as the natural reservoir. In this study, we show that cattle experimentally infected with IDV can shed virus and transmit it to other cattle through direct contact, but not to ferrets through

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. Neutralizing activities against seasonal influenza viruses in human intravenous immunoglobulin

    PubMed Central

    Onodera, Hiroyuki; Urayama, Takeru; Hirota, Kazue; Maeda, Kazuhiro; Kubota-Koketsu, Ritsuko; Takahashi, Kazuo; Hagiwara, Katsuro; Okuno, Yoshinobu; Ikuta, Kazuyoshi; Yunoki, Mikihiro

    2017-01-01

    Influenza viruses A/H1N1, A/H3N2, and B are known seasonal viruses that undergo annual mutation. Intravenous immunoglobulin (IVIG) contains anti-seasonal influenza virus globulins. Although the virus-neutralizing (VN) titer is an indicator of protective antibodies, changes in this titer over extended time periods have yet to be examined. In this study, variations in hemagglutination inhibition (HI) and VN titers against seasonal influenza viruses in IVIG lots over extended time periods were examined. In addition, the importance of monitoring the reactivity of IVIG against seasonal influenza viruses with varying antigenicity was evaluated. A/H1N1, A/H3N2, and B influenza virus strains and IVIG lots manufactured from 1999 to 2014 were examined. The HI titer was measured by standard methods. The VN titer was measured using a micro-focus method. IVIG exhibited significant HI and VN titers against all investigated strains. Our results suggest that the donor population maintains both specific and cross-reactive antibodies against seasonal influenza viruses, except in cases of pandemic viruses, despite major antigen changes. The titers against seasonal influenza vaccine strains, including past strains, were stable over short time periods but increased slowly over time. PMID:28331286

  2. 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.

  3. Origin and evolution of influenza virus hemagglutinin genes.

    PubMed

    Suzuki, Yoshiyuki; Nei, Masatoshi

    2002-04-01

    Influenza A, B, and C viruses are the etiological agents of influenza. Hemagglutinin (HA) is the major envelope glycoprotein of influenza A and B viruses, and hemagglutinin-esterase (HE) in influenza C viruses is a protein homologous to HA. Because influenza A virus pandemics in humans appear to occur when new subtypes of HA genes are introduced from aquatic birds that are known to be the natural reservoir of the viruses, an understanding of the origin and evolution of HA genes is of particular importance. We therefore conducted a phylogenetic analysis of HA and HE genes and showed that the influenza A and B virus HA genes diverged much earlier than the divergence between different subtypes of influenza A virus HA genes. The rate of amino acid substitution for A virus HAs from duck, a natural reservoir, was estimated to be 3.19 x 10(-4) per site per year, which was slower than that for human and swine A virus HAs but similar to that for influenza B and C virus HAs (HEs). Using this substitution rate from the duck, we estimated that the divergences between different subtypes of A virus HA genes occurred from several thousand to several hundred years ago. In particular, the earliest divergence time was estimated to be about 2,000 years ago. Also, the A virus HA gene diverged from the B virus HA gene about 4,000 years ago and from the C virus HE gene about 8,000 years ago. These time estimates are much earlier than the previous ones.

  4. Pandemic threat posed by avian influenza A viruses.

    PubMed

    Horimoto, T; Kawaoka, Y

    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.

  5. 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

  6. 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

  7. 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.

  8. Development of Framework for Assessing Influenza Virus Pandemic Risk.

    PubMed

    Trock, Susan C; Burke, Stephen A; Cox, Nancy J

    2015-08-01

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

  9. 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

  10. Influenza A virus infections in swine: pathogenesis and diagnosis.

    PubMed

    Janke, B H

    2014-03-01

    Influenza has been recognized as a respiratory disease in swine since its first appearance concurrent with the 1918 "Spanish flu" human pandemic. All influenza viruses of significance in swine are type A, subtype H1N1, H1N2, or H3N2 viruses. Influenza viruses infect epithelial cells lining the surface of the respiratory tract, inducing prominent necrotizing bronchitis and bronchiolitis and variable interstitial pneumonia. Cell death is due to direct virus infection and to insult directed by leukocytes and cytokines of the innate immune system. The most virulent viruses consistently express the following characteristics of infection: (1) higher or more prolonged virus replication, (2) excessive cytokine induction, and (3) replication in the lower respiratory tract. Nearly all the viral proteins contribute to virulence. Pigs are susceptible to infection with both human and avian viruses, which often results in gene reassortment between these viruses and endemic swine viruses. The receptors on the epithelial cells lining the respiratory tract are major determinants of infection by influenza viruses from other hosts. The polymerases, especially PB2, also influence cross-species infection. Methods of diagnosis and characterization of influenza viruses that infect swine have improved over the years, driven both by the availability of new technologies and by the necessity of keeping up with changes in the virus. Testing of oral fluids from pigs for virus and antibody is a recent development that allows efficient sampling of large numbers of animals.

  11. Influenza A virus infection complicated by fatal myocarditis.

    PubMed

    Nolte, K B; Alakija, P; Oty, G; Shaw, M W; Subbarao, K; Guarner, J; Shieh, W J; Dawson, J E; Morken, T; Cox, N J; Zaki, S R

    2000-12-01

    Influenza virus typically causes a febrile respiratory illness, but it can present with a variety of other clinical manifestations. We report a fatal case of myocarditis associated with influenza A infection. A previously healthy 11-year-old girl had malaise and fever for approximately 1 week before a sudden, witnessed fatal collapse at home. Autopsy revealed a pericardial effusion, a mixed lymphocytic and neutrophilic myocarditis, a mild lymphocytic interstitial pneumonia, focal bronchial/bronchiolar mucosal necrosis, and histologic changes consistent with asthma. Infection with influenza A (H3N2) was confirmed by virus isolation from a postmortem nasopharyngeal swab. Attempts to isolate virus from heart and lung tissue were unsuccessful. Immunohistochemical tests directed against influenza A antigens and in situ hybridization for influenza A genetic material demonstrated positive staining in bronchial epithelial cells, whereas heart sections were negative. Sudden death is a rare complication of influenza and may be caused by myocarditis. Forensic pathologists should be aware that postmortem nasopharyngeal swabs for viral culture and immunohistochemical or in situ hybridization procedures on lung tissue might be necessary to achieve a diagnosis. Because neither culturable virus nor influenza viral antigen could be identified in heart tissue, the pathogenesis of influenza myocarditis in this case is unlikely to be the result of direct infection of myocardium by the virus. The risk factors for developing myocarditis during an influenza infection are unknown.

  12. 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.

  13. 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.

  14. Protecting poultry workers from exposure to avian influenza viruses.

    PubMed

    MacMahon, Kathleen L; Delaney, Lisa J; Kullman, Greg; Gibbins, John D; Decker, John; Kiefer, Max J

    2008-01-01

    Emerging zoonotic diseases are of increasing regional and global importance. Preventing occupational exposure to zoonotic diseases protects workers as well as their families, communities, and the public health. Workers can be protected from zoonotic diseases most effectively by preventing and controlling diseases in animals, reducing workplace exposures, and educating workers. Certain avian influenza viruses are potential zoonotic disease agents that may be transmitted from infected birds to humans. Poultry workers are at risk of becoming infected with these viruses if they are exposed to infected birds or virus-contaminated materials or environments. Critical components of worker protection include educating employers and training poultry workers about occupational exposure to avian influenza viruses. Other recommendations for protecting poultry workers include the use of good hygiene and work practices, personal protective clothing and equipment, vaccination for seasonal influenza viruses, antiviral medication, and medical surveillance. Current recommendations for protecting poultry workers from exposure to avian influenza viruses are summarized in this article.

  15. Influenza virus antigenicity and broadly neutralizing epitopes.

    PubMed

    Air, Gillian M

    2015-04-01

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

  16. Emerging, novel, and known influenza virus infections in humans.

    PubMed

    Tang, Julian W; Shetty, Nandini; Lam, Tommy T Y; Hon, K L Ellis

    2010-09-01

    Influenza viruses continue to cause yearly epidemics and occasional pandemics in humans. In recent years, the threat of a possible influenza pandemic arising from the avian influenza A(H5N1) virus has prompted the development of comprehensive pandemic preparedness programs in many countries. The recent emergence of the pandemic influenza A(H1N1) 2009 virus from the Americas in early 2009, although surprising in its geographic and zoonotic origins, has tested these preparedness programs and revealed areas in which further work is necessary. Nevertheless, the plethora of epidemiologic, diagnostic, mathematical and phylogenetic modeling, and investigative methodologies developed since the severe acute respiratory syndrome outbreak of 2003 and the subsequent sporadic human cases of avian influenza have been applied effectively and rapidly to the emergence of this novel pandemic virus. This article summarizes some of the findings from such investigations, including recommendations for the management of patients infected with this newly emerged pathogen.

  17. 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

  18. Influenza virus resistance to human neutralizing antibodies.

    PubMed

    Crowe, James E

    2012-01-01

    The human antibody repertoire has an exceptionally large capacity to recognize new or changing antigens through combinatorial and junctional diversity established at the time of V(D)J recombination and through somatic hypermutation. Influenza viruses exhibit a relentless capacity to escape the human antibody response by altering the amino acids of their surface proteins in hypervariable domains that exhibit a high level of structural plasticity. Both parties in this high-stakes game of shape shifting drive structural evolution of their functional proteins (the B cell receptor/antibody on one side and the viral hemagglutinin and neuraminidase proteins on the other) using error-prone polymerase systems. It is likely that most of the genetic mutations that occur in these systems are deleterious, resulting in the failure of the B cell or virus with mutations to propagate in the immune repertoire or viral quasispecies. A subset of mutations is tolerated in functional surface proteins that enter the B cell or virus progeny pool. In both cases, selection occurs in the population of mutated and unmutated species. In cases where the functional avidity of the B cell receptor is increased significantly, that clone may be selected for preferential expansion. In contrast, an influenza virus that "escapes" the inhibitory effect of secreted antibodies may represent a high proportion of the progeny virus in that host. The recent paper by O'Donnell et al. [C. D. O'Donnell et al., mBio 3(3):e00120-12, 2012] identifies a mechanism for antibody resistance that does not require escape from binding but rather achieves a greater efficiency in replication.

  19. 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.

  20. 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.

  1. 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

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

    PubMed

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

    2016-03-01

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

  3. Development of Eurasian H7N7/PR8 high growth reassortant virus for clinical evaluation as an inactivated pandemic influenza vaccine.

    PubMed

    Jadhao, Samadhan J; Achenbach, Jenna; Swayne, David E; Donis, Ruben; Cox, Nancy; Matsuoka, Yumiko

    2008-03-25

    Avian-to-human transmission of the high pathogenicity (HP) H7N7 subtype avian influenza viruses in the Netherlands during 2003 caused zoonotic infections in 89 people, including a case of acute fatal respiratory distress syndrome. Public health emergency preparedness against H7N7 avian influenza viruses with pandemic potential includes the development of vaccine candidate viruses. In order to develop a high growth reassortant vaccine candidate virus, low pathogenicity (LP) A/mallard/Netherlands/12/2000 (H7N3) and A/mallard/Netherlands/2/2000 (H10N7) strains were selected as donors of the H7 haemagglutinin and N7 neuraminidase genes, respectively. The donor viruses exhibited high amino acid sequence homology with the surface glycoproteins of A/Netherlands/219/03 H7N7 virus (NL219), an isolate recovered from the fatal human case. Adhering to the seasonal influenza vaccine licensure regulations, we generated a H7N7/PR8 reassortant containing desired surface glycoprotein genes from the mallard viruses and internal genes of A/Puerto Rico/8/34 human vaccine strain (H1N1). Antigenic analysis revealed that the vaccine candidate virus confers broad antigenic cross-reactivity against contemporary Eurasian and the North American H7 subtype human isolates. Mice immunized with formalin inactivated (FI) H7N7/PR8 whole virus vaccine with or without aluminum hydroxide adjuvant conferred clinical protection from mortality and reduced pulmonary replication of the NL219 challenge virus. The FI H7N7/PR8 whole virus vaccine also afforded cross-protection in mice at the pulmonary level against antigenically distinct North American LP A/Canada/444/04 (H7N3) human isolate. The vaccine candidate virus satisfied the agricultural safety requirements for chickens, proved safe in mice, and has entered in phase-I human clinical trial in the United States.

  4. Hemagglutinin-esterase-fusion (HEF) protein of influenza C virus.

    PubMed

    Wang, Mingyang; Veit, Michael

    2016-01-01

    Influenza C virus, a member of the Orthomyxoviridae family, causes flu-like disease but typically only with mild symptoms. Humans are the main reservoir of the virus, but it also infects pigs and dogs. Very recently, influenza C-like viruses were isolated from pigs and cattle that differ from classical influenza C virus and might constitute a new influenza virus genus. Influenza C virus is unique since it contains only one spike protein, the hemagglutinin-esterase-fusion glycoprotein HEF that possesses receptor binding, receptor destroying and membrane fusion activities, thus combining the functions of Hemagglutinin (HA) and Neuraminidase (NA) of influenza A and B viruses. Here we briefly review the epidemiology and pathology of the virus and the morphology of virus particles and their genome. The main focus is on the structure of the HEF protein as well as on its co- and post-translational modification, such as N-glycosylation, disulfide bond formation, S-acylation and proteolytic cleavage into HEF1 and HEF2 subunits. Finally, we describe the functions of HEF: receptor binding, esterase activity and membrane fusion.

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

    PubMed

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

    2017-02-09

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

  6. Avian influenza: mixed infections and missing viruses.

    PubMed

    Lindsay, LeAnn L; Kelly, Terra R; Plancarte, Magdalena; Schobel, Seth; Lin, Xudong; Dugan, Vivien G; Wentworth, David E; Boyce, Walter M

    2013-08-05

    A high prevalence and diversity of avian influenza (AI) viruses were detected in a population of wild mallards sampled during summer 2011 in California, providing an opportunity to compare results obtained before and after virus culture. We tested cloacal swab samples prior to culture by matrix real-time PCR, and by amplifying and sequencing a 640bp portion of the hemagglutinin (HA) gene. Each sample was also inoculated into embryonated chicken eggs, and full genome sequences were determined for cultured viruses. While low matrix Ct values were a good predictor of virus isolation from eggs, samples with high or undetectable Ct values also yielded isolates. Furthermore, a single passage in eggs altered the occurrence and detection of viral strains, and mixed infections (different HA subtypes) were detected less frequently after culture. There is no gold standard or perfect reference comparison for surveillance of unknown viruses, and true negatives are difficult to distinguish from false negatives. This study showed that sequencing samples prior to culture increases the detection of mixed infections and enhances the identification of viral strains and sequences that may have changed or even disappeared during culture.

  7. Influenza Viruses: Breaking All the Rules

    PubMed Central

    Taubenberger, Jeffery K.; Morens, David M.

    2013-01-01

    ABSTRACT Influenza A viruses (IAV) are significant pathogens able to repeatedly switch hosts to infect multiple avian and mammalian species, including humans. The unpredictability of IAV evolution and interspecies movement creates continual public health challenges, such as the emergence of the 2009 pandemic H1N1 virus from swine, as well as pandemic threats from the ongoing H5N1 and the recent H7N9 epizootics. In the last decade there has been increased concern about the “dual use” nature of microbiology, and a set of guidelines covering “dual use research of concern” includes seven categories of potentially problematic scientific experiments. In this Perspective, we consider how in nature IAV continually undergo “dual use experiments” as a matter of evolution and selection, and we conclude that studying these properties of IAV is critical for mitigating and preventing future epidemics and pandemics. PMID:23860766

  8. 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.

  9. 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

  10. 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

    2014-05-02

    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.

  11. Diversity of influenza viruses in swine and the emergence of a novel human pandemic influenza A (H1N1).

    PubMed

    Brockwell-Staats, Christy; Webster, Robert G; Webby, Richard J

    2009-09-01

    The novel H1N1 influenza virus that emerged in humans in Mexico in early 2009 and transmitted efficiently in the human population with global spread has been declared a pandemic strain. Here we review influenza infections in swine since 1918 and the introduction of different avian and human influenza virus genes into swine influenza viruses of North America and Eurasia. These introductions often result in viruses of increased fitness for pigs that occasionally transmit to humans. The novel virus affecting humans is derived from a North American swine influenza virus that has acquired two gene segments [Neuraminidase (NA) and Matrix (M)] from the European swine lineages. This reassortant appears to have increased fitness in humans. The potential for increased virulence in humans and of further reassortment between the novel H1N1 influenza virus and oseltamivir resistant seasonal H1N1 or with highly pathogenic H5N1 influenza stresses the need for urgent pandemic planning.

  12. 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

  13. Experimental vaccines against potentially pandemic and highly pathogenic avian influenza viruses

    PubMed Central

    Mooney, Alaina J; Tompkins, S Mark

    2013-01-01

    Influenza A viruses continue to emerge and re-emerge, causing outbreaks, epidemics and occasionally pandemics. While the influenza vaccines licensed for public use are generally effective against seasonal influenza, issues arise with production, immunogenicity, and efficacy in the case of vaccines against pandemic and emerging influenza viruses, and highly pathogenic avian influenza virus in particular. Thus, there is need of improved influenza vaccines and vaccination strategies. This review discusses advances in alternative influenza vaccines, touching briefly on licensed vaccines and vaccine antigens; then reviewing recombinant subunit vaccines, virus-like particle vaccines and DNA vaccines, with the main focus on virus-vectored vaccine approaches. PMID:23440999

  14. A placebo-controlled dose response study of the reactogenicity and immunogenicity of a live cold-recombinant influenza B virus vaccine in healthy volunteers.

    PubMed

    Ganzinger, U; Bachmayer, H; Liehl, E; Martindale, J J; Hamilton, F; Kuwert, E K

    1988-06-01

    A live cold-recombinant influenza B virus vaccine (RB77) was given intranasally in a placebo-controlled, double blind study to volunteers in dosages of 10(7.9) EID50/ml, 10(7.25) EID50/ml, 10(5.7) EID50/ml. The tolerability, safety, and immunogenicity of the vaccine were investigated. No revertant virus was found in nasal swabs taken after immunisation. Local reactions were mild and showed a significant increase over the placebo only in the highest dose group. Systemic reactions were not different from the placebo. A significant increase in haemagglutinin inhibition titre was found in the highest dose group against the immunising strain (RB77) and the two wild strains B/TEC and B/Sing.

  15. 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...

  16. Influenza A virus pathogenesis and vaccination in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. 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.

  18. 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.

  19. The quest of influenza A viruses for new hosts.

    PubMed

    Liu, M; Guan, Y; Peiris, M; He, S; Webby, R J; Perez, D; Webster, R G

    2003-01-01

    There is increasing evidence that stable lineages of influenza viruses are being established in chickens. H9N2 viruses are established in chickens in Eurasia, and there are increasing reports of H3N2, H6N1, and H6N2 influenza viruses in chickens both in Asia and North America. Surveillance in a live poultry market in Nanchang, South Central China, reveals that influenza viruses were isolated form 1% of fecal samples taken from healthy poultry over the course of 16 months. The highest isolation rates were from chickens (1.3%) and ducks (1.2%), followed by quail (0.8%), then pigeon (0.5%). H3N6, H9N2, H2N9, and H4N6 viruses were isolated from multiple samples, while single isolates of H1N1, H3N2, and H3N3 viruses were made. Representatives of each virus subtype were experimentally inoculated into both quail and chickens. All the viruses replicated in the trachea of quail, but efficient replication in chickens was confined to 25% of the tested isolates. In quail, these viruses were shed primarily by the aerosol route, raising the possibility that quail may be the "route modulator" that changes the route of transmission of influenza viruses from fecal-oral to aerosol transmission. Thus, quail may play an important role in the natural history of influenza viruses. The pros and cons of the use of inactivated and recombinant fowl pox-influenza vaccines to control the spread of avian influenza are also evaluated.

  20. 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

  1. 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.

  2. Transfection-mediated recombination of influenza A virus.

    PubMed Central

    Bergmann, M; García-Sastre, A; Palese, P

    1992-01-01

    Several mechanisms, including a high mutation rate and reassortment of genes, have been found to be responsible for the variability of influenza A viruses. RNA recombination would be another mechanism leading to genetic variation; however, recombination has only rarely been reported to occur in influenza viruses. During ribonucleoprotein transfection experiments designed to generate viable influenza viruses from in vitro-synthesized RNA, we discovered several viruses which must have originated from recombination events. The ribonucleoprotein transfection system may enhance the formation of viruses which result from jumping of the viral polymerase between RNAs or from ligation of different viral RNAs. Five different recombinant viruses are described. Two of these, REC1 and REC2, contain a neuraminidase (NA) gene whose defective polyadenylation signal has been repaired via intergenic recombination; 124 and 95 nucleotides have been added, respectively. Another virus, REC5, must have originated by multiple recombination events since it contains a mosaic gene with sequences derived from the NA gene of influenza A/WSN/33 virus and the matrix, polymerase protein PB1, and NA genes of influenza A/PR/8/34 virus. Images PMID:1279208

  3. Ecology of avian influenza viruses in a changing world

    PubMed Central

    Vandegrift, Kurt J.; Sokolow, Susanne H.; Daszak, Peter; Kilpatrick, A. Marm

    2010-01-01

    Influenza A virus infections result in ~500,000 human deaths per year and many more sub-lethal infections. Wild birds are recognized as the ancestral host of influenza A viruses, and avian viruses have contributed genetic material to most human viruses, including subtypes H5N1 and H1N1. Thus, influenza virus transmission in wild and domestic animals and humans is intimately connected. Here we review how anthropogenic change, including human population growth, land use, climate change, globalization of trade, agricultural intensification, and changes in vaccine technology may alter the evolution and transmission of influenza viruses. Evidence suggests that viral transmission in domestic poultry, spillover to other domestic animals, wild birds and humans, and the potential for subsequent pandemic spread, are all increasing. We highlight four areas in need of research: drivers of viral subtype dynamics; ecological and evolutionary determinants of transmissibility and virulence in birds and humans; the impact of changing land use and climate on hosts, viruses, and transmission; and the impact of influenza viruses on wild bird hosts, including their ability to migrate while shedding virus. PMID:20536820

  4. 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

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

    PubMed

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

    2012-01-11

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

  6. Evolution of equine influenza virus in vaccinated horses.

    PubMed

    Murcia, Pablo R; Baillie, Gregory J; Stack, J Conrad; Jervis, Carley; Elton, Debra; Mumford, Jennifer A; Daly, Janet; Kellam, Paul; Grenfell, Bryan T; Holmes, Edward C; Wood, James L N

    2013-04-01

    Influenza A viruses are characterized by their ability to evade host immunity, even in vaccinated individuals. To determine how prior immunity shapes viral diversity in vivo, we studied the intra- and interhost evolution of equine influenza virus in vaccinated horses. Although the level and structure of genetic diversity were similar to those in naïve horses, intrahost bottlenecks may be more stringent in vaccinated animals, and mutations shared among horses often fall close to putative antigenic sites.

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

    PubMed Central

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

    2001-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. Genetic Characterization of Circulating 2015 A(H1N1)pdm09 Influenza Viruses from Eastern India

    PubMed Central

    Mukherjee, Anupam; Nayak, Mukti Kant; Dutta, Shanta; Panda, Samiran; Satpathi, Biswa Ranjan; Chawla-Sarkar, Mamta

    2016-01-01

    In 2015, the swine derived A(H1N1)pdm09 pandemic strain outbreak became widespread throughout the different states of India. The reported cases and deaths in 2015 surpassed the previous years with more than 39000 laboratory confirmed cases and a death toll of more than 2500 people. There are relatively limited complete genetic sequences available for this virus from Asian countries. In this study, we describe the full genome analysis of influenza 2015 A(H1N1)pdm09 viruses isolated from West Bengal between January through December 2015. The phylogenetic analysis of the haemagglutinin sequence revealed clustering with globally circulating strains of genogroup 6B. This was further confirmed by the constructed concatenated tree using all eight complete gene segments of Kolkata A(H1N1)pdm09 isolates with the other strains from different timeline and lineages. A study from Massachusetts Institute of Technology (MIT) in 2015 reported novel mutations T200A and D225N in haemagglutinin gene of a 2014 Indian strain (A/India/6427/2014). However, in all the pandemic strains of 2014–2015 reported from India, so far including A(H1N1)pdm09 strains from Kolkata, D225N mutation was not observed, though the T200A mutation was found to be conserved. Neuraminidase gene of the analyzed strains did not show any oseltamivir resistant mutation H275Y suggesting continuation of Tamiflu® as drug of choice. The amino acid sequences of the all gene segments from 2015 A(H1N1)pdm09 isolates identified several new mutations compared to the 2009 A(H1N1)pdm09 strains, which may have contributed towards enhanced virulence, compared to 2009 A(H1N1)pdm09 strains. PMID:27997573

  10. VIRAPOPS2 supports the influenza virus reassortments

    PubMed Central

    2014-01-01

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

  11. 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.

  12. An Ultrasensitive Mechanism Regulates Influenza Virus-Induced Inflammation.

    PubMed

    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

    2015-06-01

    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.

  13. 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

  14. Phylogenetic analysis of the non-structural (NS) gene of influenza A viruses isolated from mallards in Northern Europe in 2005

    PubMed Central

    Zohari, Siamak; Gyarmati, Péter; Ejdersund, Anneli; Berglöf, Ulla; Thorén, Peter; Ehrenberg, Maria; Czifra, György; Belák, Sándor; Waldenström, Jonas; Olsen, Björn; Berg, Mikael

    2008-01-01

    Background Although the important role of the non-structural 1 (NS) gene of influenza A in virulence of the virus is well established, our knowledge about the extent of variation in the NS gene pool of influenza A viruses in their natural reservoirs in Europe is incomplete. In this study we determined the subtypes and prevalence of influenza A viruses present in mallards in Northern Europe and further analysed the NS gene of these isolates in order to obtain a more detailed knowledge about the genetic variation of NS gene of influenza A virus in their natural hosts. Results A total number of 45 influenza A viruses of different subtypes were studied. Eleven haemagglutinin- and nine neuraminidase subtypes in twelve combinations were found among the isolated viruses. Each NS gene reported here consisted of 890 nucleotides; there were no deletions or insertions. Phylogenetic analysis clearly shows that two distinct gene pools, corresponding to both NS allele A and B, were present at the same time in the same geographic location in the mallard populations in Northern Europe. A comparison of nucleotide sequences of isolated viruses revealed a substantial number of silent mutations, which results in high degree of homology in amino acid sequences. The degree of variation within the alleles is very low. In our study allele A viruses displays a maximum of 5% amino acid divergence while allele B viruses display only 2% amino acid divergence. All the viruses isolated from mallards in Northern Europe possessed the typical avian ESEV amino acid sequence at the C-terminal end of the NS1 protein. Conclusion Our finding indicates the existence of a large reservoir of different influenza A viruses in mallards population in Northern Europe. Although our phylogenetic analysis clearly shows that two distinct gene pools, corresponding to both NS allele A and B, were present in the mallards populations in Northern Europe, allele B viruses appear to be less common in natural host species

  15. Interaction of influenza virus proteins with nucleosomes

    SciTech Connect

    Garcia-Robles, Inmaculada; Akarsu, Hatice; Mueller, Christoph W.; Ruigrok, Rob W.H.; Baudin, Florence . E-mail: baudin@embl-grenoble.fr

    2005-02-05

    During influenza virus infection, transcription and replication of the viral RNA take place in the cell nucleus. Directly after entry in the nucleus the viral ribonucleoproteins (RNPs, the viral subunits containing vRNA, nucleoprotein and the viral polymerase) are tightly associated with the nuclear matrix. Here, we have analysed the binding of RNPs, M1 and NS2/NEP proteins to purified nucleosomes, reconstituted histone octamers and purified single histones. RNPs and M1 both bind to the chromatin components but at two different sites, RNP to the histone tails and M1 to the globular domain of the histone octamer. NS2/NEP did not bind to nucleosomes at all. The possible consequences of these findings for nuclear release of newly made RNPs and for other processes during the infection cycle are discussed.

  16. Avian influenza virus risk assessment in falconry

    PubMed Central

    2011-01-01

    Background There is a continuing threat of human infections with avian influenza viruses (AIV). In this regard falconers might be a potential risk group because they have close contact to their hunting birds (raptors such as falcons and hawks) as well as their avian prey such as gulls and ducks. Both (hunting birds and prey birds) seem to be highly susceptible to some AIV strains, especially H5N1. We therefore conducted a field study to investigate AIV infections in falconers, their falconry birds as well as prey birds. Findings During 2 hunting seasons (2006/2007 and 2007/2008) falconers took tracheal and cloacal swabs from 1080 prey birds that were captured by their falconry birds (n = 54) in Germany. AIV-RNA of subtypes H6, H9, or H13 was detected in swabs of 4.1% of gulls (n = 74) and 3.8% of ducks (n = 53) using RT-PCR. The remaining 953 sampled prey birds and all falconry birds were negative. Blood samples of the falconry birds tested negative for AIV specific antibodies. Serum samples from all 43 falconers reacted positive in influenza A virus-specific ELISA, but remained negative using microneutralisation test against subtypes H5 and H7 and haemagglutination inhibition test against subtypes H6, H9 and H13. Conclusion Although we were able to detect AIV-RNA in samples from prey birds, the corresponding falconry birds and falconers did not become infected. Currently falconers do not seem to carry a high risk for getting infected with AIV through handling their falconry birds and their prey. PMID:21513552

  17. Zanamivir-resistant influenza viruses with a novel neuraminidase mutation.

    PubMed

    Hurt, Aeron C; Holien, Jessica K; Parker, Michael; Kelso, Anne; Barr, Ian G

    2009-10-01

    The neuraminidase inhibitors zanamivir and oseltamivir are marketed for the treatment and prophylaxis of influenza and have been stockpiled by many countries for use in a pandemic. Although recent surveillance has identified a striking increase in the frequency of oseltamivir-resistant seasonal influenza A (H1N1) viruses in Europe, the United States, Oceania, and South Africa, to date there have been no reports of significant zanamivir resistance among influenza A (H1N1) viruses or any other human influenza viruses. We investigated the frequency of oseltamivir and zanamivir resistance in circulating seasonal influenza A (H1N1) viruses in Australasia and Southeast Asia. Analysis of 391 influenza A (H1N1) viruses isolated between 2006 and early 2008 from Australasia and Southeast Asia revealed nine viruses (2.3%) that demonstrated markedly reduced zanamivir susceptibility and contained a previously undescribed Gln136Lys (Q136K) neuraminidase mutation. The mutation had no effect on oseltamivir susceptibility but caused approximately a 300-fold and a 70-fold reduction in zanamivir and peramivir susceptibility, respectively. The role of the Q136K mutation in conferring zanamivir resistance was confirmed using reverse genetics. Interestingly, the mutation was not detected in the primary clinical specimens from which these mutant isolates were grown, suggesting that the resistant viruses either occurred in very low proportions in the primary clinical specimens or arose during MDCK cell culture passage. Compared to susceptible influenza A (H1N1) viruses, the Q136K mutant strains displayed greater viral fitness than the wild-type virus in MDCK cells but equivalent infectivity and transmissibility in a ferret model.

  18. Protection against Influenza Virus Infection of Mice Fed Bifidobacterium breve YIT4064

    PubMed Central

    Yasui, Hisako; Kiyoshima, Junko; Hori, Tetuji; Shida, Kan

    1999-01-01

    Mice fed Bifidobacterium breve YIT4064 and immunized orally with influenza virus were more strongly protected against influenza virus infection of the lower respiratory tract than ones immunized with influenza virus only. The number of mice with enhanced anti-influenza virus immunoglobulin G (IgG) in serum upon oral administration of B. breve YIT4064 and oral immunization with influenza virus was significantly greater than that upon oral immunization with influenza virus only. These findings demonstrated that the oral administration of B. breve YIT4064 increased anti-influenza virus IgG antibodies in serum and protected against influenza virus infection. The oral administration of B. breve YIT4064 may enhance antigen-specific IgG against various pathogenic antigens taken orally and induce protection against various virus infections. PMID:10066652

  19. 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

  20. 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

    2016-08-22

    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.

  1. Canalization of the evolutionary trajectory of the human influenza virus

    PubMed Central

    2012-01-01

    Background Since its emergence in 1968, influenza A (H3N2) has evolved extensively in genotype and antigenic phenotype. However, despite strong pressure to evolve away from human immunity and to diversify in antigenic phenotype, H3N2 influenza shows paradoxically limited genetic and antigenic diversity present at any one time. Here, we propose a simple model of antigenic evolution in the influenza virus that accounts for this apparent discrepancy. Results In this model, antigenic phenotype is represented by a N-dimensional vector, and virus mutations perturb phenotype within this continuous Euclidean space. We implement this model in a large-scale individual-based simulation, and in doing so, we find a remarkable correspondence between model behavior and observed influenza dynamics. This model displays rapid evolution but low standing diversity and simultaneously accounts for the epidemiological, genetic, antigenic, and geographical patterns displayed by the virus. We find that evolution away from existing human immunity results in rapid population turnover in the influenza virus and that this population turnover occurs primarily along a single antigenic axis. Conclusions Selective dynamics induce a canalized evolutionary trajectory, in which the evolutionary fate of the influenza population is surprisingly repeatable. In the model, the influenza population shows a 1- to 2-year timescale of repeatability, suggesting a window in which evolutionary dynamics could be, in theory, predictable. PMID:22546494

  2. Secondary bacterial infections in influenza virus infection pathogenesis.

    PubMed

    Smith, Amber M; McCullers, Jonathan A

    2014-01-01

    Influenza is often complicated by bacterial pathogens that colonize the nasopharynx and invade the middle ear and/or lung epithelium. Incidence and pathogenicity of influenza-bacterial coinfections are multifactorial processes that involve various pathogenic virulence factors and host responses with distinct site- and strain-specific differences. Animal models and kinetic models have improved our understanding of how influenza viruses interact with their bacterial co-pathogens and the accompanying immune responses. Data from these models indicate that considerable alterations in epithelial surfaces and aberrant immune responses lead to severe inflammation, a key driver of bacterial acquisition and infection severity following influenza. However, further experimental and analytical studies are essential to determining the full mechanistic spectrum of different viral and bacterial strains and species and to finding new ways to prevent and treat influenza-associated bacterial coinfections. Here, we review recent advances regarding transmission and disease potential of influenza-associated bacterial infections and discuss the current gaps in knowledge.

  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. Evolution and Divergence of H3N8 Equine Influenza Viruses Circulating in the United Kingdom from 2013 to 2015.

    PubMed

    Rash, Adam; Morton, Rachel; Woodward, Alana; Maes, Olivia; McCauley, John; Bryant, Neil; Elton, Debra

    2017-02-08

    Equine influenza viruses (EIV) are a major cause of acute respiratory disease in horses worldwide and occasionally also affect vaccinated animals. Like other influenza A viruses, they undergo antigenic drift, highlighting the importance of both surveillance and virus characterisation in order for vaccine strains to be kept up to date. The aim of the work reported here was to monitor the genetic and antigenic changes occurring in EIV circulating in the UK from 2013 to 2015 and to identify any evidence of vaccine breakdown in the field. Virus isolation, reverse transcription polymerase chain reaction (RT-PCR) and sequencing were performed on EIV-positive nasopharyngeal swab samples submitted to the Diagnostic Laboratory Services at the Animal Health Trust (AHT). Phylogenetic analyses were completed for the haemagglutinin-1 (HA1) and neuraminidase (NA) genes using PhyML and amino acid sequences compared against the current World Organisation for Animal Health (OIE)-recommended Florida clade 2 vaccine strain. Substitutions between the new isolates and the vaccine strain were mapped onto the three-dimensional structure protein structures using PyMol. Antigenic analyses were carried out by haemagglutination inhibition assay using a panel of post-infection ferret antisera. Sixty-nine outbreaks of equine influenza in the UK were reported by the AHT between January 2013 and December 2015. Forty-seven viruses were successfully isolated in eggs from 41 of the outbreaks. Only three cases of vaccine breakdown were identified and in each case the vaccine used contained a virus antigen not currently recommended for equine influenza vaccines. Nucleotide sequencing of the HA and NA genes revealed that all of the viruses belonged to the Florida clade 2 sub-lineage of H3N8 EIV. Phylogenetic and sequence analyses showed that the two sub-populations, previously identified within clade 2, continued to circulate and had accrued further amino acid substitutions. Antigenic characterisation

  6. Evolution and Divergence of H3N8 Equine Influenza Viruses Circulating in the United Kingdom from 2013 to 2015

    PubMed Central

    Rash, Adam; Morton, Rachel; Woodward, Alana; Maes, Olivia; McCauley, John; Bryant, Neil; Elton, Debra

    2017-01-01

    Equine influenza viruses (EIV) are a major cause of acute respiratory disease in horses worldwide and occasionally also affect vaccinated animals. Like other influenza A viruses, they undergo antigenic drift, highlighting the importance of both surveillance and virus characterisation in order for vaccine strains to be kept up to date. The aim of the work reported here was to monitor the genetic and antigenic changes occurring in EIV circulating in the UK from 2013 to 2015 and to identify any evidence of vaccine breakdown in the field. Virus isolation, reverse transcription polymerase chain reaction (RT-PCR) and sequencing were performed on EIV-positive nasopharyngeal swab samples submitted to the Diagnostic Laboratory Services at the Animal Health Trust (AHT). Phylogenetic analyses were completed for the haemagglutinin-1 (HA1) and neuraminidase (NA) genes using PhyML and amino acid sequences compared against the current World Organisation for Animal Health (OIE)-recommended Florida clade 2 vaccine strain. Substitutions between the new isolates and the vaccine strain were mapped onto the three-dimensional structure protein structures using PyMol. Antigenic analyses were carried out by haemagglutination inhibition assay using a panel of post-infection ferret antisera. Sixty-nine outbreaks of equine influenza in the UK were reported by the AHT between January 2013 and December 2015. Forty-seven viruses were successfully isolated in eggs from 41 of the outbreaks. Only three cases of vaccine breakdown were identified and in each case the vaccine used contained a virus antigen not currently recommended for equine influenza vaccines. Nucleotide sequencing of the HA and NA genes revealed that all of the viruses belonged to the Florida clade 2 sub-lineage of H3N8 EIV. Phylogenetic and sequence analyses showed that the two sub-populations, previously identified within clade 2, continued to circulate and had accrued further amino acid substitutions. Antigenic characterisation

  7. Human Infections with Novel Reassortant Influenza A(H3N2)v Viruses, United States, 2011

    PubMed Central

    Lindstrom, Stephen; Garten, Rebecca; Balish, Amanda; Shu, Bo; Emery, Shannon; Berman, LaShondra; Barnes, Nathelia; Sleeman, Katrina; Gubareva, Larisa; Villanueva, Julie

    2012-01-01

    During July–December 2011, a variant virus, influenza A(H3N2)v, caused 12 human cases of influenza. The virus contained genes originating from swine, avian, and human viruses, including the M gene from influenza A(H1N1)pdm09 virus. Influenza A(H3N2)v viruses were antigenically distinct from seasonal influenza viruses and similar to proposed vaccine virus A/Minnesota/11/2010. PMID:22516540

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

    PubMed

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

    2016-01-15

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

  9. 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

  10. THE INFECTION OF FERRETS WITH SWINE INFLUENZA VIRUS

    PubMed Central

    Shope, Richard E.

    1934-01-01

    The experiments described confirm the earlier observation of Smith, Andrewes, and Laidlaw that the swine influenza virus is pathogenic for ferrets when administered intranasally. A disease that is clinically more severe and pathologically more extensive than that described by the above workers is obtained if inoculation with the virus is performed under ether anesthesia. Animals infected in this way show at autopsy an edematous type of pneumonia of lobar distribution which may terminate fatally. The virus maintains its pathogenicity for ferrets when stored in 50 per cent glycerol at refrigerator temperature for as long as 75 days. After serial passage through 16 ferrets the virus is still capable of inducing swine influenza when mixed with H. influenzae suis and administered intranasally to swine. Ferret passage causes no apparent attenuation of the virus for swine. Serum from pigs recovered from swine influenza is capable of neutralizing the ferret-passaged virus for either swine or ferrets. Likewise serum from recovered ferrets neutralizes the swine influenza virus for either ferrets or swine. PMID:19870285

  11. Circulation of influenza B lineages in northern Viet Nam, 2007–2014

    PubMed Central

    Le, Thi Thanh; Pham, Thu Hang; Pham, Thi Hien; Nguyen, Le Khanh Hang; Hoang, Vu Mai Phuong; Tran, Thu Huong; Nguyen, Vu Son; Ngo, Huong Giang

    2015-01-01

    Introduction Influenza B viruses circulate throughout Viet Nam, and their activities vary by region. There have been two antigenically distinct lineages of influenza B viruses co-circulating in the past 20 years; however, only one lineage is selected as a component of contemporary trivalent seasonal influenza vaccines. To improve the understanding of circulating influenza B lineages and influenza vaccine mismatches, we report the virus lineages circulating in northern Viet Nam over an eight-year period (2007–2014). Methods Lineages of 331 influenza B viruses were characterized by haemagglutination inhibition assay against standard reference ferret (Yamagata) and sheep (Victoria) antisera. Sequence analysis of the haemagglutinin gene was performed in 64 selected influenza B isolates. Results The proportion of influenza B lineages changed by year. The Yamagata lineage predominated in 2007, 2008 and 2012; the Victoria lineage predominated in 2009–2014 except 2012. The two lineages showed continuous evolution over time. The Northern Hemisphere’s influenza vaccine components were mismatched with the predominant circulating viruses in 2007, 2009 and 2014. Discussion The seasonality of influenza B activity is more variable in tropical and subtropical regions than in temperate zones. Our data showed a common co-circulation of both influenza B lineages in northern Viet Nam, and it was difficult to predict which one was the predominant lineage. Quadrivalent influenza vaccines containing both lineages may improve the effectiveness of influenza vaccine programmes in the future. PMID:26798557

  12. Construction of yellow fever-influenza A chimeric virus particles.

    PubMed

    Oliveira, B C E P D; Liberto, M I M; Barth, O M; Cabral, M C

    2002-12-01

    In order to obtain a better understanding of the functional mechanisms involved in the fusogenesis of enveloped viruses, the influenza A (X31) and the yellow fever (17DD) virus particles were used to construct a chimeric structure based on their distinct pH requirements for fusion, and the distinct malleability of their nucleocapsids. The malleable nucleocapsid of the influenza A virus particle is characterized by a pleomorphic configuration when observed by electron microscopy. A heat inactivated preparation of X31 virus was used as a lectin to interact with the sialic acid domains present in the 17DD virus envelope. The E spikes of 17DD virus were induced to promote fusion of both envelopes, creating a double genome enveloped structure, the chimeric yellow fever-influenza A virus particle. These chimeric viral particles, originally denominated 'partículas virais quiméricas' (PVQ), were characterized by their infectious capacity for different biological systems. Cell inoculation with PVQ resulted in viral products that showed similar characteristics to those obtained after 17DD virus infections. Our findings open new opportunities towards the understanding of both virus particles and aspects of cellular physiologic quality control. The yellow fever-influenza A chimeric particles, by means of their hybrid composition, should be a valuable tool in the study of cell biology and the function of viral components.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  14. 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

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

    PubMed

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

    2007-01-01

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

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

    PubMed

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

    2015-03-01

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

  17. IL-6 ameliorates acute lung injury in influenza virus infection

    PubMed Central

    Yang, Mei-Lin; Wang, Chung-Teng; Yang, Shiu-Ju; Leu, Chia-Hsing; Chen, Shun-Hua; Wu, Chao-Liang; Shiau, Ai-Li

    2017-01-01

    Interleukin 6 (IL-6) is involved in innate and adaptive immune responses to defend against pathogens. It also participates in the process of influenza infection by affecting viral clearance and immune cell responses. However, whether IL-6 impacts lung repair in influenza pathogenesis remains unclear. Here, we studied the role of IL-6 in acute influenza infection in mice. IL-6-deficient mice infected with influenza virus exhibited higher lethality, lost more body weight and had higher fibroblast accumulation and lower extracellular matrix (ECM) turnover in the lung than their wild-type counterparts. Deficiency in IL-6 enhanced proliferation, migration and survival of lung fibroblasts, as well as increased virus-induced apoptosis of lung epithelial cells. IL-6-deficient lung fibroblasts produced elevated levels of TGF-β, which may contribute to their survival. Furthermore, macrophage recruitment to the lung and phagocytic activities of macrophages during influenza infection were reduced in IL-6-deficient mice. Collectively, our results indicate that IL-6 is crucial for lung repair after influenza-induced lung injury through reducing fibroblast accumulation, promoting epithelial cell survival, increasing macrophage recruitment to the lung and enhancing phagocytosis of viruses by macrophages. This study suggests that IL-6 may be exploited for lung repair during influenza infection. PMID:28262742

  18. Evaluation of recombinant influenza virus-simian immunodeficiency virus vaccines in macaques.

    PubMed

    Sexton, Amy; De Rose, Robert; Reece, Jeanette C; Alcantara, Sheilajen; Loh, Liyen; Moffat, Jessica M; Laurie, Karen; Hurt, Aeron; Doherty, Peter C; Turner, Stephen J; Kent, Stephen J; Stambas, John

    2009-08-01

    There is an urgent need for human immunodeficiency virus (HIV) vaccines that induce robust mucosal immunity. Influenza A viruses (both H1N1 and H3N2) were engineered to express simian immunodeficiency virus (SIV) CD8 T-cell epitopes and evaluated following administration to the respiratory tracts of 11 pigtail macaques. Influenza virus was readily detected from respiratory tract secretions, although the infections were asymptomatic. Animals seroconverted to influenza virus and generated CD8 and CD4 T-cell responses to influenza virus proteins. SIV-specific CD8 T-cell responses bearing the mucosal homing marker beta7 integrin were induced by vaccination of naïve animals. Further, SIV-specific CD8 T-cell responses could be boosted by recombinant influenza virus-SIV vaccination of animals with already-established SIV infection. Sequential vaccination with influenza virus-SIV recombinants of different subtypes (H1N1 followed by H3N2 or vice versa) produced only a limited boost in immunity, probably reflecting T-cell immunity to conserved internal proteins of influenza A virus. SIV challenge of macaques vaccinated with an influenza virus expressing a single SIV CD8 T cell resulted in a large anamnestic recall CD8 T-cell response, but immune escape rapidly ensued and there was no impact on chronic SIV viremia. Although our results suggest that influenza virus-HIV vaccines hold promise for the induction of mucosal immunity to HIV, broader antigen cover will be needed to limit cytotoxic T-lymphocyte escape.

  19. 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

  20. Intra- and interhost evolutionary dynamics of equine influenza virus.

    PubMed

    Murcia, Pablo R; Baillie, Gregory J; Daly, Janet; Elton, Debra; Jervis, Carley; Mumford, Jennifer A; Newton, Richard; Parrish, Colin R; Hoelzer, Karin; Dougan, Gordon; Parkhill, Julian; Lennard, Nicola; Ormond, Doug; Moule, Sharon; Whitwham, Andrew; McCauley, John W; McKinley, Trevelyan J; Holmes, Edward C; Grenfell, Bryan T; Wood, James L N

    2010-07-01

    Determining the evolutionary basis of cross-species transmission and immune evasion is key to understanding the mechanisms that control the emergence of either new viruses or novel antigenic variants with pandemic potential. The hemagglutinin glycoprotein of influenza A viruses is a critical host range determinant and a major target of neutralizing antibodies. Equine influenza virus (EIV) is a significant pathogen of the horse that causes periodical outbreaks of disease even in populations with high vaccination coverage. EIV has also jumped the species barrier and emerged as a novel respiratory pathogen in dogs, canine influenza virus. We studied the dynamics of equine influenza virus evolution in horses at the intrahost level and how this evolutionary process is affected by interhost transmission in a natural setting. To this end, we performed clonal sequencing of the hemagglutinin 1 gene derived from individual animals at different times postinfection. Our results show that despite the population consensus sequence remaining invariant, genetically distinct subpopulations persist during the course of infection and are also transmitted, with some variants likely to change antigenicity. We also detected a natural case of mixed infection in an animal infected during an outbreak of equine influenza, raising the possibility of reassortment between different strains of virus. In sum, our data suggest that transmission bottlenecks may not be as narrow as originally perceived and that the genetic diversity required to adapt to new host species may be partially present in the donor host and potentially transmitted to the recipient host.

  1. Swine Influenza Viruses: a North American Perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Rapidly expanding range of highly pathogenic avian influenza viruses

    USGS Publications Warehouse

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

    2015-01-01

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

  3. 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...

  4. 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)

  5. Influenza D Virus in Cattle, France, 2011–2014

    PubMed Central

    Pelletier, Claire; Meyer, Gilles

    2015-01-01

    A new influenza virus, genus D, isolated in US pigs and cattle, has also been circulating in cattle in France. It was first identified there in 2011, and an increase was detected in 2014. The virus genome in France is 94%–99% identical to its US counterpart, which suggests intercontinental spillover. PMID:25628038

  6. THE INFECTION OF MICE WITH SWINE INFLUENZA VIRUS

    PubMed Central

    Shope, Richard E.

    1935-01-01

    The experiments confirm the earlier observation of Andrewes, Laidlaw and Smith that the swine influenza virus is pathogenic for white mice when administered intranasally. Two field strains of the swine influenza virus were found to differ in their initial pathogenicity for mice. One strain was apparently fully pathogenic even in its 1st mouse passage while the other required 2 or 3 mouse passages to acquire full virulence for this species. Both strains, however, were initially infectious for mice, without the necessity of intervening ferret passages. There is no evidence that bacteria play any significant rôle in the mouse disease though essential in that of swine, and fatal pneumonias can be produced in mice by pure virus infections. Mice surviving the virus disease are immune to reinfection for at least a month. In mice the disease is not contagious though it is notably so in swine. The virus, while regularly producing fatal pneumonias when administered intranasally to mice, appears to be completely innocuous when given subcutaneously or intraperitoneally. Prolonged serial passage of the virus in mice does not influence its infectivity or virulence for swine or ferrets. It is a stable virus so far as its infectivity is concerned, and can be transferred at will from any one of its three known susceptible hosts to any other. In discussing these facts the stability of the swine influenza virus has been contrasted with the apparent instability of freshly isolated strains of the human influenza virus. Though the mouse is an un-natural host for the virus it is, nevertheless, useful for the study of those aspects of swine influenza which have to do with the virus only. PMID:19870434

  7. 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.

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

    PubMed

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

    2016-02-01

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

  9. Influenza A(H1N1)pdm09 Virus Infection in Giant Pandas, China

    PubMed Central

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

    2014-01-01

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

  10. 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.

  11. Single radial immunodiffusion potency test for standardization of indigenous equine influenza vaccine.

    PubMed

    Gupta, A K; Yadav, M P; Uppal, P K

    1993-12-01

    Single radial immunodiffusion (SRD) assays were used for measuring the haemagglutinin antigen contents of equine influenza vaccine prepared from an Indian virus isolate. A/Equine-2/Ludhiana/1/87 (H3N8). Five different preparations of the vaccine were standardized by SRD to prepare 913 doses, each containing 20 micrograms HA/ml-1 dose-1. This test also showed influenza virus subtype specificity as no cross reaction was observed between subtype 1 (H7N7) and subtype 2 (H3N8) viruses.

  12. 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...

  13. 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...

  14. Plaque inhibition assay for drug susceptibility testing of influenza viruses.

    PubMed Central

    Hayden, F G; Cote, K M; Douglas, R G

    1980-01-01

    The relative antiviral activities of four drugs against contemporary strains of influenza A and B viruses were determined in Madin-Darby canine kidney cell monolayers with a plaque inhibition assay. This assay proved to be a reliable, rapid method of determining 50% inhibitory concentrations that correlated well with clinically achievable drug levels and the results of clinical trials. Contemporary strains of influenza A viruses (subtypes H1N1, H3N2, HSW1N1) required amantadine hydrochloride and rimantadine hydrochloride 50% inhibitory concentrations in the range of 0.2 to 0.4 microgram/ml, whereas 50% inhibitory concentrations ranged from approximately 50 to 100 micrograms/ml against influenza B viruses. Ribavirin was approximately 10-fold less active than amantadine hydrochloride against influenza A viruses, and the ribavirin 50% inhibitory concentrations against both influenza A and B viruses ranged from 2.6 to 6.8 micrograms/ml. Inosiplex had no antiviral activity in this test system. PMID:7396473

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

    PubMed

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

    2015-08-01

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

  16. Effective primary isolation of wild-type canine distemper virus in MDCK, MV1 Lu and Vero cells without nucleotide sequence changes within the entire haemagglutinin protein gene and in subgenomic sections of the fusion and phospho protein genes.

    PubMed

    Lednicky, John A; Meehan, Thomas P; Kinsel, Michael J; Dubach, Jean; Hungerford, Laura L; Sarich, Nicolene A; Witecki, Kelley E; Braid, Michael D; Pedrak, Casandra; Houde, Christiane M

    2004-06-15

    Canine distemper virus (CDV) is an important pathogen of many carnivores. We are developing a field-based model of morbillivirus virulence and pathogenesis through a study of distemper in naturally infected free-ranging raccoons. The isolation of CDV from raccoon tissues is essential for this work. CDV has often been isolated from animals only after co-cultivation of infected tissues with peripheral blood mononuclear cells derived from specific pathogen-free dogs or similar methods. We explored the utility and consequences of a simpler and cheaper alternative: CDV isolation in Vero, MDCK, and MV1 Lu cells. Virus growth was detected first in MDCK cells, whereas viral cytopathic effects were most obvious in Vero cells. CDV growth in MV1 Lu cells was relatively protracted and occurred without the formation of cytopathic effects. In primary CDV isolates, the entire nucleotide sequence of the receptor binding haemagglutinin (H) gene, and subgenomic fusion (F) and phospho (P) protein gene sequences corresponding to nt 5399-5733 and 2132-2563 of CDV reference strain Onderstepoort, respectively, were identical to those in matched infected tissues. Virus isolation confirmed the presence of CDV in instances where RT-PCR failed to detect CDV in infected tissues. Different viral phenotypes and genotypes were detected. The conservation of H gene sequences in primary CDV isolates suggests that MDCK, MV1 Lu, and Vero cells express proper receptors for wild-type CDV.

  17. 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.

  18. Transmission of avian H9N2 influenza viruses in a murine model.

    PubMed

    Wu, Rui; Sui, Zhiwei; Liu, Zewen; Liang, Wangwang; Yang, Keli; Xiong, Zhongliang; Xu, Diping

    2010-05-19

    Avian H9N2 influenza viruses have circulated widely in domestic poultry around the world, resulting in occasional transmission of virus from infected poultry to humans. However, it is unknown whether H9N2 influenza virus has acquired the ability to be transmitted from human to human. Here, we report that mouse-adapted H9N2 influenza viruses can replicate efficiently and are lethal for several strains of mice. To evaluate the transmissibility of mouse-adapted H9N2 influenza viruses, we carried out transmission studies in mice using both contact and respiratory droplet routes. Our results indicate that mouse-adapted H9N2 influenza viruses can replicate efficiently and be transmitted between mice. This suggests that once H9N2 influenza viruses adapt to new host, they should present potential public health risks, therefore, urgent attention should be paid to H9N2 influenza viruses.

  19. 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

  20. 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.

  1. Virulence and genetic compatibility of polymerase reassortant viruses derived from the pandemic (H1N1) 2009 influenza virus and circulating influenza A viruses.

    PubMed

    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

    2011-07-01

    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.

  2. [Polymorphism of current human influenza A and B virus population].

    PubMed

    Grinbaum, E B; Litvinova, O M; Bannikov, A I; Konovalenko, I B; Chernookaia, N Iu; Iukhnova, L G; Kiselev, O I

    1994-01-01

    During the past years, the etiological situation has been significantly complicated. It is characterized by simultaneous circulation of A(H1N1), A(H3N2) and influenza B viruses and by the isolation of reassortant strains and viruses, which are atypical in relation to the process of their natural variability. The antigenic properties of epidemic strains and unusual isolates were investigated. The marked heterogeneity of the A(H3N2) influenza viruses was demonstrated. It was determined by the circulation of several antigenic variants during the epidemic. Two separate antigenic lineage of the influenza B viruses--b/Victoria/2/87 and B/Yamagata/16/88--cocirculated in our country in 1991. Since 1986, all the influenza A(H1N1) viruses have been considered to be varieties of the reference strain A/Taiwan/1/86. A direct correlation was found between some atypical viruses and the vaccine strains previously used.

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

    PubMed

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

    2014-01-01

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

  4. Analysis by single-gene reassortment demonstrates that the 1918 influenza virus is functionally compatible with a low-pathogenicity avian influenza virus in mice.

    PubMed

    Qi, Li; Davis, A Sally; Jagger, Brett W; Schwartzman, Louis M; Dunham, Eleca J; Kash, John C; Taubenberger, Jeffery K

    2012-09-01

    The 1918-1919 "Spanish" influenza pandemic is estimated to have caused 50 million deaths worldwide. Understanding the origin, virulence, and pathogenic properties of past pandemic influenza viruses, including the 1918 virus, is crucial for current public health preparedness and future pandemic planning. The origin of the 1918 pandemic virus has not been resolved, but its coding sequences are very like those of avian influenza virus. The proteins encoded by the 1918 virus differ from typical low-pathogenicity avian influenza viruses at only a small number of amino acids in each open reading frame. In this study, a series of chimeric 1918 influenza viruses were created in which each of the eight 1918 pandemic virus gene segments was replaced individually with the corresponding gene segment of a prototypical low-pathogenicity avian influenza (LPAI) H1N1 virus in order to investigate functional compatibility of the 1918 virus genome with gene segments from an LPAI virus and to identify gene segments and mutations important for mammalian adaptation. This set of eight "7:1" chimeric viruses was compared to the parental 1918 and LPAI H1N1 viruses in intranasally infected mice. Seven of the 1918 LPAI 7:1 chimeric viruses replicated and caused disease equivalent to the fully reconstructed 1918 virus. Only the chimeric 1918 virus containing the avian influenza PB2 gene segment was attenuated in mice. This attenuation could be corrected by the single E627K amino acid change, further confirming the importance of this change in mammalian adaptation and mouse pathogenicity. While the mechanisms of influenza virus host switch, and particularly mammalian host adaptation are still only partly understood, these data suggest that the 1918 virus, whatever its origin, is very similar to avian influenza virus.

  5. Influenza a virus entry: implications in virulence and future therapeutics.

    PubMed

    Rumschlag-Booms, Emily; Rong, Lijun

    2013-01-01

    Influenza A viruses have broad host tropism, being able to infect a range of hosts from wild fowl to swine to humans. This broad tropism makes highly pathogenic influenza A strains, such as H5N1, potentially dangerous to humans if they gain the ability to jump from an animal reservoir to humans. How influenza A viruses are able to jump the species barrier is incompletely understood due to the complex genetic nature of the viral surface glycoprotein, hemagglutinin, which mediates entry, combined with the virus's ability to use various receptor linkages. Current therapeutics against influenza A include those that target the uncoating process after entry as well as those that prevent viral budding. While there are therapeutics in development that target entry, currently there are none clinically available. We review here the genetics of influenza A viruses that contribute to entry tropism, how these genetic alterations may contribute to receptor usage and species tropism, as well as how novel therapeutics can be developed that target the major surface glycoprotein, hemagglutinin.

  6. 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.

  7. Active surveillance of avian influenza viruses in Egyptian poultry, 2015.

    PubMed

    Kayed, A S; Kandeil, A; El Shesheny, R; Ali, M A; Kayali, G

    2016-10-02

    Surveillance for avian influenza viruses in Egyptian poultry has been conducted since 2009. Up to 2011, all the detected viruses were H5N1, and the overall prevalence was 5%. In 2011, H9N2 viruses were observed to be co-circulating and co-infecting the same hosts as H5N1 viruses. Since then, the detection rate has increased to around 10%. In the 2014-2015 winter season, H5N1 was circulating heavily in poultry flocks and caused an unprecedented number of human infections. In contrast, surveillance in the last quarter of 2015 indicated a near absence of H5N1 in Egyptian poultry. Surveillance for avian influenza viruses must continue in Egypt to monitor further developments in H5N1 circulation in poultry.

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

    PubMed

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

    2006-12-01

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

  9. The Activity of Influenza and Influenza-like Viruses in Individuals Aged over 14 in the 2015/2016 Influenza Season in Poland.

    PubMed

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

    2017-02-15

    Infections in every epidemic season induced by respiratory viruses, especially by the influenza virus, are the cause of many illnesses and complications which often end in death. The aim of this study was to determine the activity of influenza and influenza-like viruses in individuals aged over of 14 in Poland during the 2015/2016 epidemic season. A total of 5070 specimens taken from patients were analyzed. The presence of the influenza virus was confirmed in 40.2% of cases, among which the subtype A/H1N1/pdm09 (62.6% positive samples) predominated. The analysis of confirmed influenza and influenza-like viruses in individuals divided into four age-groups demonstrate that the highest morbidity was reported for the age ranges: 45-64 (13.1%) and 26-44 (12.6%) years. An increase in the number of influenza type B cases (23.7% positive samples), which was the main cause of morbidity in the age group 15-25 years, was noticeable. Given the epidemiological and virological data, the 2015/2016 season in Poland was characterized by increased activity of the influenza virus compared to the previous season. In the 2015/2016 season, there were more than 3.8 million cases and suspected cases of influenza and influenza-like illness, more than 15,000 hospitalizations, and up to 140 deaths.

  10. Multiplex Assay for Simultaneously Typing and Subtyping Influenza Viruses by Use of an Electronic Microarray ▿

    PubMed Central

    Huang, Ying; Tang, Huong; Duffy, Stuart; Hong, Yuwen; Norman, Sylvia; Ghosh, Madhu; He, Jie; Bose, Michael; Henrickson, Kelly J.; Fan, Jiang; Kraft, Andrea J.; Weisburg, William G.; Mather, Elizabeth L.

    2009-01-01

    We report on the use of an electronic microarray to simultaneously type influenza A and B viruses and to distinguish influenza A virus subtypes H1N1 and H3N2 from the potentially pandemic avian virus subtype H5N1. The assay targets seven genes: the H1, H3, H5, N1, and N2 genes of influenza A virus; the matrix protein M1 gene of influenza A virus; and the nonstructural protein (NS) gene of influenza B virus. By combining a two-step reverse transcription-multiplex PCR with typing and subtyping on the electronic microarray, the assay achieved an analytical sensitivity of 102 to 103 copies of transcripts per reaction for each of the genes. The assay correctly typed and subtyped 15 different influenza virus isolates, including two influenza B virus, five A/H1N1, six A/H3N2, and two A/H5N1 isolates. In addition, the assay correctly identified 8 out of 10 diluted, archived avian influenza virus specimens with complete typing and subtyping information and 2 specimens with partial subtyping information. In a study of 146 human clinical specimens that had previously been shown to be positive for influenza virus or another respiratory virus, the assay showed a clinical sensitivity of 96% and a clinical specificity of 100%. The assay is a rapid, accurate, user-friendly method for simultaneously typing and subtyping influenza viruses. PMID:19073867

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

    PubMed Central

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

    2011-01-01

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

  12. Limiting influenza virus, HIV and dengue virus infection by targeting viral proteostasis

    PubMed Central

    Heaton, Nicholas S.; Moshkina, Natasha; Fenouil, Romain; Gardner, Thomas J.; Aguirre, Sebastian; Shah, Priya S.; Zhao, Nan; Manganaro, Lara; Hultquist, Judd; Noel, Justine; Sachs, David; Hamilton, Jennifer; Leon, Paul E.; Chawdury, Amit; Tripathy, Shashank; Melegari, Camilla; Campisi, Laura; Hai, Rong; Metreveli, Giorgi; Gamarnik, Andrea V.; García-Sastre, Adolfo; Greenbaum, Benjamin; Simon, Viviana; Fernandez-Sesma, Ana; Krogan, Nevan; Mulder, Lubbertus C.F.; van Bakel, Harm; Tortorella, Domenico; Taunton, Jack; Palese, Peter; Marazzi, Ivan

    2016-01-01

    Viruses are obligate parasites as they require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy to suppress viral replication and a potential pan antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling, genetic, and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses, and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication we have identified targetable host factors for broad-spectrum antiviral therapies. PMID:26789921

  13. A vaccine prepared from a non-pathogenic H5N1 influenza virus strain from the influenza virus library conferred protective immunity to chickens against the challenge with antigenically drifted highly pathogenic avian influenza virus.

    PubMed

    Samad, Rozanah Asmah Abdul; Nomura, Naoki; Tsuda, Yoshimi; Manzoor, Rashid; Kajihara, Masahiro; Tomabechi, Daisuke; Sasaki, Takashi; Kokumai, Norihide; Ohgitani, Toshiaki; Okamatsu, Masatoshi; Takada, Ayato; Sakoda, Yoshihiro; Kida, Hiroshi

    2011-02-01

    Inactivated influenza virus vaccine prepared from a non-pathogenic influenza virus strain A/duck/Hokkaido/Vac-1/2004 (H5N1) from the virus library conferred protective immunity to chickens against the challenge of antigenically drifted highly pathogenic avian influenza virus (HPAIV), A/whooper swan/Hokkaido/1/2008 (H5N1). The efficacy of the vaccine was comparable to that prepared from genetically modified HPAIV strain deltaRRRRK rg-A/ whooper swan/Mongolia/3/2005 (H5N1), which is more antigenically related to the challenge virus strain, in chickens.

  14. Interspecies transmission and reassortment of influenza A viruses in pigs and turkeys in the United States.

    PubMed

    Wright, S M; Kawaoka, Y; Sharp, G B; Senne, D A; Webster, R G

    1992-08-15

    Genetic reassortment between influenza A viruses in humans and in animals and birds has been implicated in the appearance of new pandemics of human influenza. To determine whether such reassortment has occurred in the United States, the authors compared the genetic origins of gene segments of 73 swine influenza virus isolates (1976-1990), representing 11 states, and 11 turkey virus isolates (1980-1989), representing eight states. The host origin of gene segments encoding the internal proteins of H1N1 swine and turkey influenza viruses was identified by developing a dot-blot assay. All gene segments of swine influenza viruses were characteristic of influenza virus genes from that species, indicating that pigs may not be frequent participants in interspecies genetic exchange and reassortment of influenza viruses in the United States. In contrast, 73% of the turkey influenza virus isolates contained genes of swine origin. One turkey isolate was a reassortant having three genes characteristic of avian influenza virus and three of swine origin. These findings document a high degree of genetic exchange and reassortment of influenza A viruses in domestic turkeys in the United States. The molecular biologic techniques used by the authors should aid future epidemiologic studies of influenza pandemics.

  15. Neuraminidase as an enzymatic marker for detecting airborne Influenza virus and other viruses.

    PubMed

    Turgeon, Nathalie; Toulouse, Marie-Josée; Ho, Jim; Li, Dongqing; Duchaine, Caroline

    2017-02-01

    Little information is available regarding the effectiveness of air samplers to collect viruses and regarding the effects of sampling processes on viral integrity. The neuraminidase enzyme is present on the surface of viruses that are of agricultural and medical importance. It has been demonstrated that viruses carrying this enzyme can be detected using commercial substrates without having to process the sample by methods such as RNA extraction. This project aims at evaluating the effects of 3 aerosol-sampling devices on the neuraminidase enzyme activity of airborne viruses. The purified neuraminidase enzymes from Clostridium perfringens, a strain of Influenza A (H1N1) virus, the FluMist influenza vaccine, and the Newcastle disease virus were used as models. The neuraminidase models were aerosolized in aerosol chambers and sampled with 3 different air samplers (SKC BioSampler, 3-piece cassettes with polycarbonate filters, and Coriolis μ) to assess the effect on neuraminidase enzyme activity. Our results demonstrated that Influenza virus and Newcastle disease virus neuraminidase enzymes are resistant to aerosolization and sampling with all air samplers tested. Moreover, we demonstrated that the enzymatic neuraminidase assay is as sensitive as RT-qPCR for detecting low concentrations of Influenza virus and Newcastle disease virus. Therefore, given the sensitivity of the assay and its compatibility with air sampling methods, viruses carrying the neuraminidase enzyme can be rapidly detected from air samples using neuraminidase activity assay without having to preprocess the samples.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. 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

  19. 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

  20. 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

  1. 21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Reagents for detection of specific novel influenza... Reagents § 866.3332 Reagents for detection of specific novel influenza A viruses. (a) Identification. Reagents for detection of specific novel influenza A viruses are devices that are intended for use in...

  2. 21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Reagents for detection of specific novel influenza... Reagents § 866.3332 Reagents for detection of specific novel influenza A viruses. (a) Identification. Reagents for detection of specific novel influenza A viruses are devices that are intended for use in...

  3. 21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Reagents for detection of specific novel influenza... Reagents § 866.3332 Reagents for detection of specific novel influenza A viruses. (a) Identification. Reagents for detection of specific novel influenza A viruses are devices that are intended for use in...

  4. 21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Reagents for detection of specific novel influenza... Reagents § 866.3332 Reagents for detection of specific novel influenza A viruses. (a) Identification. Reagents for detection of specific novel influenza A viruses are devices that are intended for use in...

  5. Pathogenesis of avian influenza A (H5N1) viruses in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background. Genetic reassortment of avian influenza H5N1 viruses with currently circulating human influenza A strains is one possibility that could lead to efficient human-to-human transmissibility. Domestic pigs which are susceptible to infection with both human and avian influenza A viruses are o...

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

    PubMed

    Dimmock, Nigel J; Easton, Andrew J

    2015-07-08

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. [Detection of influenza virus (RT-PCR assay and others)].

    PubMed

    Matsuzaki, Yoko

    2003-11-01

    Viral isolation is the conventional method for influenza virus diagnosis but it is less useful for immediate patient management. RT-PCR is the sensitive and rapid assay for the detection of respiratory viruses. Single step and multiplex RT-PCR is able to detect several viruses simultaneously in a single reaction. Real time PCR(TaqMan method) is able to detect the amplicon directly by release of a fluorescent reporter of the probe during the amplification reactions. This procedure can save time since it eliminates post-PCR processing steps. These RT-PCR methods should be useful for the accurate and rapid diagnosis of influenza virus infection, especially severe cases such as pneumonia and encephalopathy.

  9. 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

  10. 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.

  11. Initial genetic characterization of the 1918 "Spanish" influenza virus.

    PubMed

    Taubenberger, J K; Reid, A H; Krafft, A E; Bijwaard, K E; Fanning, T G

    1997-03-21

    The "Spanish" influenza pandemic killed at least 20 million people in 1918-1919, making it the worst infectious pandemic in history. Understanding the origins of the 1918 virus and the basis for its exceptional virulence may aid in the prediction of future influenza pandemics. RNA from a victim of the 1918 pandemic was isolated from a formalin-fixed, paraffin-embedded, lung tissue sample. Nine fragments of viral RNA were sequenced from the coding regions of hemagglutinin, neuraminidase, nucleoprotein, matrix protein 1, and matrix protein 2. The sequences are consistent with a novel H1N1 influenza A virus that belongs to the subgroup of strains that infect humans and swine, not the avian subgroup.

  12. Surveillance of wild birds for avian influenza virus.

    PubMed

    Hoye, Bethany J; Munster, Vincent J; Nishiura, Hiroshi; Klaassen, Marcel; Fouchier, Ron A M

    2010-12-01

    Recent demand for increased understanding of avian influenza virus in its natural hosts, together with the development of high-throughput diagnostics, has heralded a new era in wildlife disease surveillance. However, survey design, sampling, and interpretation in the context of host populations still present major challenges. We critically reviewed current surveillance to distill a series of considerations pertinent to avian influenza virus surveillance in wild birds, including consideration of what, when, where, and how many to sample in the context of survey objectives. Recognizing that wildlife disease surveillance is logistically and financially constrained, we discuss pragmatic alternatives for achieving probability-based sampling schemes that capture this host-pathogen system. We recommend hypothesis-driven surveillance through standardized, local surveys that are, in turn, strategically compiled over broad geographic areas. Rethinking the use of existing surveillance infrastructure can thereby greatly enhance our global understanding of avian influenza and other zoonotic diseases.

  13. Molecular studies of influenza B virus in the reverse genetics era.

    PubMed

    Jackson, David; Elderfield, Ruth A; Barclay, Wendy S

    2011-01-01

    Recovery of an infectious virus of defined genetic structure entirely from cDNA and the deduction of information about the virus resulting from phenotypic characterization of the mutant is the process of reverse genetics. This approach has been possible for a number of negative-strand RNA viruses since the recovery of rabies virus in 1994. However, the recovery of recombinant orthomyxoviruses posed a greater challenge due to the segmented nature of the genome. It was not until 1999 that such a system was reported for influenza A viruses, but since that time our knowledge of influenza A virus biology has grown dramatically. Annual influenza epidemics are caused not only by influenza A viruses but also by influenza B viruses. In 2002, two groups reported the successful recovery of influenza B virus entirely from cDNA. This has allowed greater depth of study into the biology of these viruses. This review will highlight the advances made in various areas of influenza B virus biology as a result of the development of reverse genetics techniques for these viruses, including (i) the importance of the non-coding regions of the influenza B virus genome; (ii) the generation of novel vaccine strains; (iii) studies into the mechanisms of drug resistance; (iv) the function(s) of viral proteins, both those analogous to influenza A virus proteins and those unique to influenza B viruses. The information generated by the application of influenza B virus reverse genetics systems will continue to contribute to our improved surveillance and control of human influenza.

  14. 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.

  15. Adapting global influenza management strategies to address emerging viruses.

    PubMed

    Noah, Diana L; Noah, James W

    2013-07-15

    Death by respiratory complications from influenza infections continues to be a major global health concern. Antiviral drugs are widely available for therapy and prophylaxis, but viral mutations have resulted in resistance that threatens to reduce the long-term utility of approved antivirals. Vaccination is the best method for controlling influenza, but vaccine strategies are blunted by virus antigenic drift and shift. Genetic shift in particular has led to four pandemics in the last century, which have prompted the development of efficient global surveillance and vaccination programs. Although the influenza pandemic of 2009 emphasized the need for the rapid standardization of global surveillance methods and the preparation and dissemination of global assay standards for improved reporting and diagnostic tools, outbreaks of novel influenza strains continue to occur, and current efforts must be enhanced by aggressive public education programs to promote increased vaccination rates in the global population. Recently, a novel H7N9 avian influenza virus with potential to become a pandemic strain emerged in China and was transmitted from animals to humans with a demonstrated >20% mortality rate. Sporadic outbreaks of highly lethal avian virus strains have already increased public awareness and altered annual vaccine production strategies to prevent the natural adaption of this virus to human-to-human transmission. Additional strategies for combating influenza include advancement of new antivirals for unexploited viral or host cellular targets; novel adjuvants and alternate vaccine delivery systems; and development of universal protein, DNA, or multivalent vaccines designed to increase immune responsiveness and enhance public health response times.

  16. Canada geese and the epidemiology of avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. 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.

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

    PubMed Central

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

    2014-01-01

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

  19. 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...

  20. 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...

  1. Generation of influenza A viruses as live but replication-incompetent virus vaccines.

    PubMed

    Si, Longlong; Xu, Huan; Zhou, Xueying; Zhang, Ziwei; Tian, Zhenyu; Wang, Yan; Wu, Yiming; Zhang, Bo; Niu, Zhenlan; Zhang, Chuanling; Fu, Ge; Xiao, Sulong; Xia, Qing; Zhang, Lihe; Zhou, Demin

    2016-12-02

    The conversion of life-threatening viruses into live but avirulent vaccines represents a revolution in vaccinology. In a proof-of-principle study, we expanded the genetic code of the genome of influenza A virus via a transgenic cell line containing orthogonal translation machinery. This generated premature termination codon (PTC)-harboring viruses that exerted full infectivity but were replication-incompetent in conventional cells. Genome-wide optimization of the sites for incorporation of multiple PTCs resulted in highly reproductive and genetically stable progeny viruses in transgenic cells. In mouse, ferret, and guinea pig models, vaccination with PTC viruses elicited robust humoral, mucosal, and T cell-mediated immunity against antigenically distinct influenza viruses and even neutralized existing infecting strains. The methods presented here may become a general approach for generating live virus vaccines that can be adapted to almost any virus.

  2. Inhibition of influenza A virus infection by ginsenosides

    PubMed Central

    Leon, Alberto J.; Kelvin, David J.

    2017-01-01

    Influenza viruses cause mild to severe respiratory infections in humans. Due to efficient means of transmission, the viruses infect human population on a large scale. Apart from vaccines, antiviral drugs are used to control infection; neuraminidase inhibitors are thought to be the first choice of treatment, particularly for severe cases. Rapidly evolving and emerging influenza viruses with increased frequency of viral resistance to these drugs stress the need to explore novel antiviral compounds. In this study, we investigated antiviral activity of ginseng extract and ginsenosides, the ginseng-derived triterpene and saponin compounds, against 2009 pandemic H1N1 virus in vitro and in vivo. Our data showed that treatment of mice with ginsenosides protected the animals from lethal 2009 pandemic H1N1 infection and lowered viral titers in animal lungs. Mechanistic studies revealed that ginsenosides interact with viral hemagglutinin protein and prevent the attachment of virus with α 2–3’ sialic acid receptors present on host cell surfaces. The interference in the viral attachment process subsequently minimizes viral entry into the cells and decreases the severity of the viral infection. We also describe that sugar moieties present in ginsenosides are indispensible for their attachment with viral HA protein. On the basis of our observations, we can say that ginsenosides are promising candidates for the development of antiviral drugs for influenza viruses. PMID:28187149

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

    PubMed

    Pearce, Melissa B; Belser, Jessica A; Gustin, Kortney M; Pappas, Claudia; Houser, Katherine V; Sun, Xiangjie; Maines, Taronna R; Pantin-Jackwood, Mary J; Katz, Jacqueline M; Tumpey, Terrence M

    2012-07-01

    The influenza virus H1N1 pandemic of 1918 was one of the worst medical catastrophes in human history. Recent studies have demonstrated that the hemagglutinin (HA) protein of the 1918 virus and 2009 H1N1 pandemic virus [A(H1N1)pdm09], the latter now a component of the seasonal trivalent inactivated influenza vaccine (TIV), share cross-reactive antigenic determinants. In this study, we demonstrate that immunization with the 2010-2011 seasonal TIV induces neutralizing antibodies that cross-react with the reconstructed 1918 pandemic virus in ferrets. TIV-immunized ferrets subsequently challenged with the 1918 virus displayed significant reductions in fever, weight loss, and virus shedding compared to these parameters in nonimmune control ferrets. Seasonal TIV was also effective in protecting against the lung infection and severe lung pathology associated with 1918 virus infection. Our data demonstrate that prior immunization with contemporary TIV provides cross-protection against the 1918 virus in ferrets. These findings suggest that exposure to A(H1N1)pdm09 through immunization may provide protection against the reconstructed 1918 virus which, as a select agent, is considered to pose both biosafety and biosecurity threats.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  6. 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

    2014-05-06

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Influenza Virus-Host Interactomes as a Basis for Antiviral Drug Development

    PubMed Central

    Watanabe, Tokiko; Kawaoka, Yoshihiro

    2016-01-01

    Currently, antiviral drugs that target specific viral protein functions are available for the treatment of influenza; however, concern regarding the emergence of drug-resistant viruses is warranted, as is the urgent need for new antiviral targets, including non-viral targets, such as host cellular factors. Viruses rely on host cellular functions to replicate, and therefore a thorough understanding of the roles of virus-host interactions during influenza virus replication is essential to develop novel anti-influenza drugs that target the host factors involved in virus replication. Here, we review recent studies that used several approaches to identify host factors involved in influenza virus replication. These studies have permitted the construction of an interactome map of virus-host interactions in the influenza virus life cycle, clarifying the entire life cycle of this virus and accelerating the development of new antiviral drugs with a low propensity for the development of resistance. PMID:26364134

  9. [Rapid diagnosis of influenza infection by PCR method--detection of influenza virus HA gene in throat swab].

    PubMed

    Morishita, T; Kobayashi, S; Miyake, T; Ishihara, Y; Isomura, S; Nakajima, S; Nakajima, K

    1992-07-01

    We studied the detection of the HA gene of human influenza viruses in throat swabs obtained from the outbreaks of influenza in school children utilizing the polymerase chain reaction (PCR) method. Sensitivity and specificity of the PCR method was compared to conventional virus isolation using MDCK cells. Three pairs of primers for PCR in detecting the HA genes of AH1, AH3, and B influenza viruses showed both subtype and type specificity. The dilution experiments showed that influenza viruses, as few as 1.1-3.5 plaque-forming units per 50 microliters, were sufficient for the detection of HA genes by PCR method and the detection rate by PCR method was 2-3 fold higher than that by conventional method. Our results showed that the PCR method was a fast, sensitive and reliable method for the diagnosis of influenza infections.

  10. 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.

  11. Linking influenza virus tissue tropism to population-level reproductive fitness.

    PubMed

    Reperant, Leslie A; Kuiken, Thijs; Grenfell, Bryan T; Osterhaus, Albert D M E; Dobson, Andrew P

    2012-01-01

    Influenza virus tissue tropism defines the host cells and tissues that support viral replication and contributes to determining which regions of the respiratory tract are infected in humans. The location of influenza virus infection along the respiratory tract is a key determinant of virus pathogenicity and transmissibility, which are at the basis of influenza burdens in the human population. As the pathogenicity and transmissibility of influenza virus ultimately determine its reproductive fitness at the population level, strong selective pressures will shape influenza virus tissue tropisms that maximize fitness. At present, the relationships between influenza virus tissue tropism within hosts and reproductive fitness at the population level are poorly understood. The selective pressures and constraints that shape tissue tropism and thereby influence the location of influenza virus infection along the respiratory tract are not well characterized. We use mathematical models that link within-host infection dynamics in a spatially-structured human respiratory tract to between-host transmission dynamics, with the aim of characterizing the possible selective pressures on influenza virus tissue tropism. The results indicate that spatial heterogeneities in virus clearance, virus pathogenicity or both, resulting from the unique structure of the respiratory tract, may drive optimal receptor binding affinity--that maximizes influenza virus reproductive fitness at the population level--towards sialic acids with α2,6 linkage to galactose. The expanding cell pool deeper down the respiratory tract, in association with lower clearance rates, may result in optimal infectivity rates--that likewise maximize influenza virus reproductive fitness at the population level--to exhibit a decreasing trend towards deeper regions of the respiratory tract. Lastly, pre-existing immunity may drive influenza virus tissue tropism towards upper regions of the respiratory tract. The proposed

  12. 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.

  13. [Favipiravir, a new concept of antiviral drug against influenza viruses].

    PubMed

    Reina, J; Reina, N

    2017-04-01

    Favipiravir (T-705) is a new antiviral drug with strong inhibitory activity on RNA-dependent RNA polymerase of most RNA virus genome. All the influenza viruses have been shown fully sensitive to this new antiviral, including genetic strains to neuraminidase inhibitors (oseltamivir) resistance. Its mechanism of action lies in blocking viral replication and induction of lethal mutagenesis which determines the loss of infective activity of influenza viruses. Its activity is particularly intense in the respiratory tract, decreasing the viral load to non-infectious levels. Clinical trials in humans have not yet completed but have very favourable results. It seems that the best therapy would be the combination of favipiravir with oseltamivir; both antivirals are synergistic and avoid the emergence of resistance.

  14. 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

  15. 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

    2016-04-12

    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.

  16. 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.

  17. Immune responses of chickens inoculated with a recombinant fowlpox vaccine coexpressing HA of H9N2 avain influenza virus and chicken IL-18.

    PubMed

    Chen, Hong-Ying; Shang, Yan-Hong; Yao, Hui-Xia; Cui, Bao-An; Zhang, Hong-Ying; Wang, Zi-Xin; Wang, Ya-Dan; Chao, An-Jun; Duan, Ting-Yun

    2011-07-01

    Control of the circulation of H9N2 avian influenza virus (AIV) is a major concern for both animal and public health, and H9N2 AIV poses a major threat to the chicken industry worldwide. Here, we developed a recombinant fowlpox virus (rFPV-HA) expressing the haemagglutinin (HA) gene of the A/CH/JY/1/05 (H9N2) influenza virus and a recombinant fowlpox virus (rFPV-HA/IL18) expressing the HA gene and chicken interleukin-18 (IL-18) gene. Recombinant plasmid pSY-HA/IL18 was constructed by cloning chicken IL-18 expression cassette into recombinant plasmid pSY-HA containing the HA gene. Two rFPVs were generated by transfecting two recombinant plasmids into the chicken embryo fibroblast cells pre-infected with S-FPV-017, and assessed for their immunological efficacy on one-day-old White Leghorn specific-pathogen-free chickens challenged with the A/CH/JY/1/05 (H9N2) strain. There was a significant difference in HI antibody levels (P<0.05) elicited by either rFPV-HA or rFPV-HA/IL18. The level of splenocyte proliferation response in the rFPV-HA/IL18-vaccinated group was significantly higher (P<0.05) than that in the rFPV-HA group. After challenge with 10(6.5)ELD(50) H9N2 AIV 43days after immunization, rFPVs vaccinated groups could prevent virus shedding and replication in multiple organs in response to H9N2 AIV infection, and rFPV-HA/IL18 vaccinated group had better inhibition of viruses than rFPV-HA vaccinated group. Our results show that the protective efficacy of the rFPV-HA vaccine could be enhanced significantly by simultaneous expression of IL-18.

  18. 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.

  19. RNA replicons - a new approach for influenza virus immunoprophylaxis.

    PubMed

    Zimmer, Gert

    2010-02-01

    RNA replicons are derived from either positive- or negative-strand RNA viruses. They represent disabled virus vectors that are not only avirulent, but also unable to revert to virulence. Due to autonomous RNA replication, RNA replicons are able to drive high level, cytosolic expression of recombinant antigens stimulating both the humoral and the cellular branch of the immune system. This review provides an update on the available literature covering influenza virus vaccines based on RNA replicons. The pros and cons of these vaccine strategies will be discussed and future perspectives disclosed.

  20. Macaque Proteome Response to Highly Pathogenic Avian Influenza and 1918 Reassortant Influenza Virus Infections▿ †

    PubMed Central

    Brown, Joseph N.; Palermo, Robert E.; Baskin, Carole R.; Gritsenko, Marina; Sabourin, Patrick J.; Long, James P.; Sabourin, Carol L.; Bielefeldt-Ohmann, Helle; García-Sastre, Adolfo; Albrecht, Randy; Tumpey, Terrence M.; Jacobs, Jon M.; Smith, Richard D.; Katze, Michael G.

    2010-01-01

    The host proteome response and molecular mechanisms that drive disease in vivo during infection by a human isolate of the highly pathogenic avian influenza virus (HPAI) and 1918 pandemic influenza virus remain poorly understood. This study presents a comprehensive characterization of the proteome response in cynomolgus macaque (Macaca fascicularis) lung tissue over 7 days of infection with HPAI (the most virulent), a reassortant virus containing 1918 hemagglutinin and neuraminidase surface proteins (intermediate virulence), or a human seasonal strain (least virulent). A high-sensitivity two-dimensional liquid chromatography-tandem mass spectroscopy strategy and functional network analysis were implemented to gain insight into response pathways activated in macaques during influenza virus infection. A macaque protein database was assembled and used in the identification of 35,239 unique peptide sequences corresponding to approximately 4,259 proteins. Quantitative analysis identified an increase in expression of 400 proteins during viral infection. The abundance levels of a subset of these 400 proteins produced strong correlations with disease progression observed in the macaques, distinguishing a “core” response to viral infection from a “high” response specific to severe disease. Proteome expression profiles revealed distinct temporal response kinetics between viral strains, with HPAI inducing the most rapid response. While proteins involved in the immune response, metabolism, and transport were increased rapidly in the lung by HPAI, the other viruses produced a delayed response, characterized by an increase in proteins involved in oxidative phosphorylation, RNA processing, and translation. Proteomic results were integrated with previous genomic and pathological analysis to characterize the dynamic nature of the influenza virus infection process. PMID:20844032

  1. Sparse evidence for equine or avian influenza virus infections among Mongolian adults with animal exposures.

    PubMed

    Khurelbaatar, Nyamdavaa; Krueger, Whitney S; Heil, Gary L; Darmaa, Badarchiin; Ulziimaa, Daramragchaa; Tserennorov, Damdindorj; Baterdene, Ariungerel; Anderson, Benjamin D; Gray, Gregory C

    2013-11-01

    In recent years, Mongolia has experienced recurrent epizootics of equine influenza virus (EIV) among its 2·1 million horses and multiple incursions of highly pathogenic avian influenza (HPAI) virus via migrating birds. No human EIV or HPAI infections have been reported. In 2009, 439 adults in Mongolia were enrolled in a population-based study of zoonotic influenza transmission. Enrollment sera were examined for serological evidence of infection with nine avian, three human, and one equine influenza virus strains. Seroreactivity was sparse among participants suggesting little human risk of zoonotic influenza infection.

  2. 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.

  3. 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 ...

  4. Guidelines for identifying homologous recombination events in influenza A virus.

    PubMed

    Boni, Maciej F; de Jong, Menno D; van Doorn, H Rogier; Holmes, Edward C

    2010-05-03

    The rapid evolution of influenza viruses occurs both clonally and non-clonally through a variety of genetic mechanisms and selection pressures. The non-clonal evolution of influenza viruses comprises relatively frequent reassortment among gene segments and a more rarely reported process of non-homologous RNA recombination. Homologous RNA recombination within segments has been proposed as a third such mechanism, but to date the evidence for the existence of this process among influenza viruses has been both weak and controversial. As homologous recombination has not yet been demonstrated in the laboratory, supporting evidence, if it exists, may come primarily from patterns of phylogenetic incongruence observed in gene sequence data. Here, we review the necessary criteria related to laboratory procedures and sample handling, bioinformatic analysis, and the known ecology and evolution of influenza viruses that need to be met in order to confirm that a homologous recombination event occurred in the history of a set of sequences. To determine if these criteria have an effect on recombination analysis, we gathered 8307 publicly available full-length sequences of influenza A segments and divided them into those that were sequenced via the National Institutes of Health Influenza Genome Sequencing Project (IGSP) and those that were not. As sample handling and sequencing are executed to a very high standard in the IGSP, these sequences should be less likely to be exposed to contamination by other samples or by laboratory strains, and thus should not exhibit laboratory-generated signals of homologous recombination. Our analysis shows that the IGSP data set contains only two phylogenetically-supported single recombinant sequences and no recombinant clades. In marked contrast, the non-IGSP data show a very large amount of potential recombination. We conclude that the presence of false positive signals in the non-IGSP data is more likely than false negatives in the IGSP data

  5. Sialylneolacto-N-tetraose c (LSTc)-bearing liposomal decoys capture influenza A virus.

    PubMed

    Hendricks, Gabriel L; Weirich, Kim L; Viswanathan, Karthik; Li, Jing; Shriver, Zachary H; Ashour, Joseph; Ploegh, Hidde L; Kurt-Jones, Evelyn A; Fygenson, Deborah K; Finberg, Robert W; Comolli, James C; Wang, Jennifer P

    2013-03-22

    Influenza is a severe disease in humans and animals with few effective therapies available. All strains of influenza virus are prone to developing drug resistance due to the high mutation rate in the viral genome. A therapeutic agent that targets a highly conserved region of the virus could bypass resistance and also be effective against multiple strains of influenza. Influenza uses many individually weak ligand binding interactions for a high avidity multivalent attachment to sialic acid-bearing cells. Polymerized sialic acid analogs can form multivalent interactions with influenza but are not ideal therapeutics due to solubility and toxicity issues. We used liposomes as a novel means for delivery of the glycan sialylneolacto-N-tetraose c (LSTc). LSTc-bearing decoy liposomes form multivalent, polymer-like interactions with influenza virus. Decoy liposomes competitively bind influenza virus in hemagglutination inhibition assays and inhibit infection of target cells in a dose-dependent manner. Inhibition is specific for influenza virus, as inhibition of Sendai virus and respiratory syncytial virus is not observed. In contrast, monovalent LSTc does not bind influenza virus or inhibit infectivity. LSTc decoy liposomes prevent the spread of influenza virus during multiple rounds of replication in vitro and extend survival of mice challenged with a lethal dose of virus. LSTc decoy liposomes co-localize with fluorescently tagged influenza virus, whereas control liposomes do not. Considering the conservation of the hemagglutinin binding pocket and the ability of decoy liposomes to form high avidity interactions with influenza hemagglutinin, our decoy liposomes have potential as a new therapeutic agent against emerging influenza strains.

  6. Sialylneolacto-N-tetraose c (LSTc)-bearing Liposomal Decoys Capture Influenza A Virus*

    PubMed Central

    Hendricks, Gabriel L.; Weirich, Kim L.; Viswanathan, Karthik; Li, Jing; Shriver, Zachary H.; Ashour, Joseph; Ploegh, Hidde L.; Kurt-Jones, Evelyn A.; Fygenson, Deborah K.; Finberg, Robert W.; Comolli, James C.; Wang, Jennifer P.

    2013-01-01

    Influenza is a severe disease in humans and animals with few effective therapies available. All strains of influenza virus are prone to developing drug resistance due to the high mutation rate in the viral genome. A therapeutic agent that targets a highly conserved region of the virus could bypass resistance and also be effective against multiple strains of influenza. Influenza uses many individually weak ligand binding interactions for a high avidity multivalent attachment to sialic acid-bearing cells. Polymerized sialic acid analogs can form multivalent interactions with influenza but are not ideal therapeutics due to solubility and toxicity issues. We used liposomes as a novel means for delivery of the glycan sialylneolacto-N-tetraose c (LSTc). LSTc-bearing decoy liposomes form multivalent, polymer-like interactions with influenza virus. Decoy liposomes competitively bind influenza virus in hemagglutination inhibition assays and inhibit infection of target cells in a dose-dependent manner. Inhibition is specific for influenza virus, as inhibition of Sendai virus and respiratory syncytial virus is not observed. In contrast, monovalent LSTc does not bind influenza virus or inhibit infectivity. LSTc decoy liposomes prevent the spread of influenza virus during multiple rounds of replication in vitro and extend survival of mice challenged with a lethal dose of virus. LSTc decoy liposomes co-localize with fluorescently tagged influenza virus, whereas control liposomes do not. Considering the conservation of the hemagglutinin binding pocket and the ability of decoy liposomes to form high avidity interactions with influenza hemagglutinin, our decoy liposomes have potential as a new therapeutic agent against emerging influenza strains. PMID:23362274

  7. Bat-derived influenza-like viruses H17N10 and H18N11.

    PubMed

    Wu, Ying; Wu, Yan; Tefsen, Boris; Shi, Yi; Gao, George F

    2014-04-01

    Shorebirds and waterfowls are believed to be the reservoir hosts for influenza viruses, whereas swine putatively act as mixing vessels. The recent identification of two influenza-like virus genomes (designated H17N10 and H18N11) from bats has challenged this notion. A crucial question concerns the role bats might play in influenza virus ecology. Structural and functional studies of the two major surface envelope proteins, hemagglutinin (HA) and neuraminidase (NA), demonstrate that neither has canonical HA or NA functions found in influenza viruses. However, putative functional modules and domains in other encoded proteins are conserved, and the N-terminal domain of the H17N10 polymerase subunit PA has a classical structure and function. Therefore, potential genomic reassortments of such influenza-like viruses with canonical influenza viruses cannot be excluded at this point and should be assessed.

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

    PubMed

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

    2005-12-01

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

  9. Phylogenetic evidence against evolutionary stasis and natural abiotic reservoirs of influenza A virus.

    PubMed

    Worobey, Michael

    2008-04-01

    Zhang et al. (G. Zhang, D. Shoham, D. Gilichinsky, S. Davydov, J. D. Castello, and S. O. Rogers, J. Virol. 80:12229-12235, 2006) have claimed to have recovered influenza A virus RNA from Siberian lake ice, postulating that ice might represent an important abiotic reservoir for the persistence and reemergence of this medically important pathogen. A rigorous phylogenetic analysis of these influenza A virus hemagglutinin gene sequences, however, indicates that they originated from a laboratory reference strain derived from the earliest human influenza A virus isolate, WS/33. Contrary to Zhang et al.'s assertions that the Siberian "ice viruses" are most closely related either to avian influenza virus or to human influenza virus strains from Asia from the 1960s (Zhang et al., J. Virol. 81:2538 [erratum], 2007), they are clearly contaminants from the WS/33 positive control used in their laboratory. There is thus no credible evidence that environmental ice acts as a biologically relevant reservoir for influenza viruses. Several additional cases with findings that seem at odds with the biology of influenza virus, including modern-looking avian influenza virus RNA sequences from an archival goose specimen collected in 1917 (T. G. Fanning, R. D. Slemons, A. H. Reid, T. A. Janczewski, J. Dean, and J. K. Taubenberger, J. Virol. 76:7860-7862, 2002), can also be explained by laboratory contamination or other experimental errors. Many putative examples of evolutionary stasis in influenza A virus appear to be due to laboratory artifacts.

  10. 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...

  11. Novel avian influenza A(H7N9) virus in tree sparrow, Shanghai, China, 2013.

    PubMed

    Zhao, Baihui; Zhang, Xi; Zhu, Wenfei; Teng, Zheng; Yu, Xuelian; Gao, Ye; Wu, Di; Pei, Enle; Yuan, Zhengan; Yang, Lei; Wang, Dayan; Shu, Yuelong; Wu, Fan

    2014-05-01

    In spring 2013, influenza A(H7N9) virus was isolated from an apparently healthy tree sparrow in Chongming Dongping National Forest Park, Shanghai City, China. The entire gene constellation of the virus is similar to that of isolates from humans, highlighting the need to monitor influenza A(H7N9) viruses in different species.

  12. 21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... A viruses. 866.3332 Section 866.3332 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Reagents § 866.3332 Reagents for detection of specific novel influenza A viruses. (a) Identification. Reagents for detection of specific novel influenza A viruses are devices that are intended for use in...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  14. Surveillance and analysis of avian influenza viruses, Australia.

    PubMed

    Hansbro, Philip M; 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

    2010-12-01

    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.

  15. 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

  16. 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

  17. Distinct Patterns of IFITM-Mediated Restriction of Filoviruses, SARS Coronavirus, and Influenza A Virus

    DTIC Science & Technology

    2011-01-06

    Distinct Patterns of IFITM-Mediated Restriction of Filoviruses, SARS Coronavirus, and Influenza A Virus I-Chueh Huang1*, Charles C. Bailey1, Jessica...identified viral restriction factors that inhibit infection mediated by the influenza A virus (IAV) hemagglutinin (HA) protein. Here we show that IFITM...Becker MM, et al. (2011) Distinct Patterns of IFITM-Mediated Restriction of Filoviruses, SARS Coronavirus, and Influenza A Virus. PLoS Pathog 7(1

  18. 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.

  19. 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.

  20. 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

  1. Characterization of the 1918 "Spanish" influenza virus matrix gene segment.

    PubMed

    Reid, Ann H; Fanning, Thomas G; Janczewski, Thomas A; McCall, Sherman; Taubenberger, Jeffery K

    2002-11-01

    The coding region of influenza A virus RNA segment 7 from the 1918 pandemic virus, consisting of the open reading frames of the two matrix genes M1 and M2, has been sequenced. While this segment is highly conserved among influenza virus strains, the 1918 sequence does not match any previously sequenced influenza virus strains. The 1918 sequence matches the consensus over the M1 RNA-binding domains and nuclear localization signal and the highly conserved transmembrane domain of M2. Amino acid changes that correlate with high yield and pathogenicity in animal models were not found in the 1918 strain. Phylogenetic analyses suggest that both genes were mammalian adapted and that the 1918 sequence is very similar to the common ancestor of all subsequent human and classical swine matrix segments. The 1918 sequence matches other mammalian strains at 4 amino acids in the extracellular domain of M2 that differ consistently between avian and mammalian strains, suggesting that the matrix segment may have been circulating in human strains for at least several years before 1918.

  2. Variability in H9N2 haemagglutinin receptor-binding preference and the pH of fusion.

    PubMed

    Peacock, Thomas P; Benton, Donald J; Sadeyen, Jean-Remy; Chang, Pengxiang; Sealy, Joshua E; Bryant, Juliet E; Martin, Stephen R; Shelton, Holly; McCauley, John W; Barclay, Wendy S; Iqbal, Munir

    2017-03-22

    H9N2 avian influenza viruses are primarily a disease of poultry; however, they occasionally infect humans and are considered a potential pandemic threat. Little work has been performed to assess the intrinsic biochemical properties related to zoonotic potential of H9N2 viruses. The objective of this study, therefore, was to investigate H9N2 haemagglutinins (HAs) using two well-known correlates for human adaption: receptor-binding avidity and pH of fusion. Receptor binding was characterized using bio-layer interferometry to measure virus binding to human and avian-like receptor analogues and the pH of fusion was assayed by syncytium formation in virus-infected cells at different pHs. We characterized contemporary H9N2 viruses of the zoonotic G1 lineage, as well as representative viruses of the zoonotic BJ94 lineage. We found that most contemporary H9N2 viruses show a preference for sulphated avian-like receptor analogues. However, the 'Eastern' G1 H9N2 viruses displayed a consistent preference in binding to a human-like receptor analogue. We demonstrate that the presence of leucine at position 226 of the HA receptor-binding site correlated poorly with the ability to bind a human-like sialic acid receptor. H9N2 HAs also display variability in their pH of fusion, ranging between pH 5.4 and 5.85 which is similar to that of the first wave of human H1N1pdm09 viruses but lower than the pH of fusion seen in zoonotic H5N1 and H7N9 viruses. Our results suggest possible molecular mechanisms that may underlie the relatively high prevalence of human zoonotic infection by particular H9N2 virus lineages.

  3. [From diagnosis to the detection of avian influenza virus].

    PubMed

    Wunderli, W

    2007-11-01

    Until now the avian influenza A (H5N1) virus is only adapted to birds. But even so infections in man are observed sporadically. Why is this possible and how big is the risk that the virus becomes fully adapted to man so that he can be transmitted easily from man to man. Two major mechanisms for the adaptation to a new host have been described: Adaptation by the accumulation of mutations in important places of the genome and adaptation through the exchange of genome segments between two different types of viruses. But there are indications that the adaptation is not linked to only one event. It is probably a multifactor event where its requirements are not all known or understood. Until now avian influenza is not adapted to man. Infection is primarily observed after close contact with infected birds or their contaminated secretions. It seems that the virus needs to reach the lower respiratory tract in order to be able to infect. The disease starts with the clinical symptoms of influenza but progresses rapidly involving primarily the lower respiratory tract causing sometimes live threatening complications. Because of the similarity of symptoms with normal flu laboratory testing is necessary to clarify the situation. Ideally a rapid test would give in a short time a result. Unfortunately this type of test shows insufficient sensitivity and for this reason is not recommended to screen suspect cases for avian influenza. For this reason the detection of the avian virus by RT-PCR in throat swabs is the method of choice in order to be able to confirm or exclude a suspect case.

  4. 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

  5. Vaccination of influenza a virus decreases transmission rates in pigs.

    PubMed

    Romagosa, Anna; Allerson, Matt; Gramer, Marie; Joo, Han Soo; Deen, John; Detmer, Susan; Torremorell, Montserrat

    2011-12-20

    Limited information is available on the transmission and spread of influenza virus in pig populations with differing immune statuses. In this study we assessed differences in transmission patterns and quantified the spread of a triple reassortant H1N1 influenza virus in naïve and vaccinated pig populations by estimating the reproduction ratio (R) of infection (i.e. the number of secondary infections caused by an infectious individual) using a deterministic Susceptible-Infectious-Recovered (SIR) model, fitted on experimental data. One hundred and ten pigs were distributed in ten isolated rooms as follows: (i) non-vaccinated (NV), (ii) vaccinated with a heterologous vaccine (HE), and (iii) vaccinated with a homologous inactivated vaccine (HO). The study was run with multiple replicates and for each replicate, an infected non-vaccinated pig was placed with 10 contact pigs for two weeks and transmission of influenza evaluated daily by analyzing individual nasal swabs by RT-PCR. A statistically significant difference between R estimates was observed between vaccinated and non-vaccinated pigs (p < 0.05). A statistically significant reduction in transmission was observed in the vaccinated groups where R (95%CI) was 1 (0.39-2.09) and 0 for the HE and the HO groups respectively, compared to an Ro value of 10.66 (6.57-16.46) in NV pigs (p < 0.05). Transmission in the HE group was delayed and variable when compared to the NV group and transmission could not be detected in the HO group. Results from this study indicate that influenza vaccines can be used to decrease susceptibility to influenza infection and decrease influenza transmission.

  6. Genetic diversity and phylogenetic analysis of highly pathogenic avian influenza (HPAI) H5N1 viruses circulating in Bangladesh from 2007-2011.

    PubMed

    Mondal, S P; Balasuriya, U B R; Yamage, M

    2013-12-01

    Highly pathogenic avian influenza (HPAI) H5N1 virus has been endemic in Bangladesh since its first isolation in February 2007. Phylogenetic analysis of the haemagglutinin (HA) gene of HPAI H5N1 viruses demonstrated that 25 Bangladeshi isolates including two human isolates from 2007-2011 along with some isolates from neighbouring Asian countries (India, Bhutan, Myanmar, Nepal, China and Vietnam) segregate into two distinct clades (2.2 and 2.3). There was clear evidence of introduction of clade 2.3.2 and 2.3.4 viruses in 2011 in addition to clade 2.2 viruses that had been in circulation in Bangladesh since 2007. The data clearly demonstrated the movement of H5N1 strains between Asian countries included in this study due to migration of wild birds and/or illegal movement of poultry across borders. Interestingly, the two human isolates were closely related to the clade 2.2 Bangladeshi chicken isolates indicating that they have originated from chickens. Furthermore, comparative amino acid sequence analysis revealed several substitutions (including 189R>K and 282I>V) in HA protein of some clade 2.2 Bangladeshi viruses including the human isolates, suggesting there was antigenic drift in clade 2.2.3 viruses that were circulating between 2008 and 2011. Overall, the data imply genetic diversity among circulating viruses and multiple introductions of H5N1 viruses with an increased risk of human infections in Bangladesh, and establishment of H5N1 virus in wild and domestic bird populations, which demands active surveillance.

  7. Molecular Epidemiology and Spatio-Temporal Dynamics of the H3N8 Equine Influenza Virus in South America

    PubMed Central

    Olguin Perglione, Cecilia; Golemba, Marcelo D.; Torres, Carolina; Barrandeguy, Maria

    2016-01-01

    Equine influenza virus (EIV) is considered the most important respiratory pathogen of horses as outbreaks of the disease lead to substantial economic losses. The H3N8 EIV has caused respiratory disease in horses across the world, including South American countries. Nucleotide and deduced amino acid sequences for the complete haemagglutinin gene of the H3N8 EIV detected in South America since 1963 were analyzed. Phylogenetic and Bayesian coalescent analyses were carried out to study the origin, the time of the most recent common ancestors (tMRCA), the demographic and the phylogeographic patterns of the H3N8 EIV. The phylogenetic analysis demonstrated that the H3N8 EIV detected in South America grouped in 5 well-supported monophyletic clades, each associated with strains of different origins. The tMRCA estimated for each group suggested that the virus was circulating in North America at least one year before its effective circulation in the South American population. Phylogenetic and coalescent analyses revealed a polyphyletic behavior of the viruses causing the outbreaks in South America between 1963 and 2012, possibly due to the introduction of at least 4 different EIVs through the international movement of horses. In addition, phylodynamic analysis suggested South America as the starting point of the spread of the H3N8 EIV in 1963 and showed migration links from the United States to South America in the subsequent EIV irruptions. Further, an increase in the relative genetic diversity was observed between 2006 and 2007 and a subsequent decline since 2009, probably due to the co-circulation of different lineages and as a result of the incorporation of the Florida clade 2 strain in vaccines, respectively. The observed data highlight the importance of epidemiological surveillance and the implementation of appropriate quarantine procedures to prevent outbreaks of the disease. PMID:27754468

  8. 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.

  9. 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.

  10. A replication-incompetent influenza virus bearing the HN glycoprotein of human parainfluenza virus as a bivalent vaccine.

    PubMed

    Kobayashi, Hirofumi; Iwatsuki-Horimoto, Kiyoko; Kiso, Maki; Uraki, Ryuta; Ichiko, Yurie; Takimoto, Toru; Kawaoka, Yoshihiro

    2013-12-16

    Influenza virus and human parainfluenza virus (HPIV) are major etiologic agents of acute respiratory illness in young children. Inactivated and live attenuated influenza vaccines are approved in several countries, yet no vaccine is licensed for HPIV. We previously showed that a replication-incompetent PB2-knockout (PB2-KO) virus that possesses a reporter gene in the coding region of the PB2 segment can serve as a platform for a bivalent vaccine. To develop a bivalent vaccine against influenza and parainfluenza virus, here, we generated a PB2-KO virus possessing the hemagglutinin-neuraminidase (HN) glycoprotein of HPIV type 3 (HPIV3), a major surface antigen of HPIV, in its PB2 segment. We confirmed that this virus replicated only in PB2-expressing cells and expressed HN. We then examined the efficacy of this virus as a bivalent vaccine in a hamster model. High levels of virus-specific IgG antibodies in sera and IgA, IgG, and IgM antibodies in bronchoalveolar lavage fluids against both influenza virus and HPIV3 were detected from hamsters immunized with this virus. The neutralizing capability of these serum antibodies was also confirmed. Moreover, the immunized hamsters were completely protected from virus challenge with influenza virus or HPIV3. These results indicate that PB2-KO virus expressing the HN of HPIV3 has the potential to be a novel bivalent vaccine against influenza and human parainfluenza viruses.

  11. Influenza virus assays based on virus‐inducible reporter cell lines

    PubMed Central

    Li, Yunsheng; Larrimer, Audrey; Curtiss, Teresa; Kim, Jaekyung; Jones, Abby; Baird‐Tomlinson, Heather; Pekosz, Andrew; Olivo, Paul D.

    2009-01-01

    Background  Virus‐inducible reporter genes have been used as the basis of virus detection and quantitation assays for a number of viruses. A strategy for influenza A virus‐induction of a reporter gene was recently described. In this report, we describe the extension of this strategy to influenza B virus, the generation of stable cell lines with influenza A and B virus‐inducible reporter genes, and the use of these cells in various clinically relevant viral assays. Each of the cell lines described herein constitutively express an RNA transcript that contains a reporter gene coding region flanked by viral 5′‐ and 3′‐untranslated regions (UTR) and therefore mimics an influenza virus genomic segment. Upon infection of the cells with influenza virus the virus‐inducible reporter gene segment (VIRGS) is replicated and transcribed by the viral polymerase complex resulting in reporter gene expression. Findings  Reporter gene induction occurs after infection with a number of laboratory strains and clinical isolates of influenza virus including several H5N1 strains. The induction is dose‐dependent and highly specific for influenza A or influenza B viruses. Conclusions  These cell lines provide the basis of simple, rapid, and objective assays that involve virus quantitation such as determination of viral titer, assessment of antiviral susceptibility, and determination of antibody neutralization titer. These cell lines could be very useful for influenza virus researchers and vaccine manufacturers. PMID:21462401

  12. Recent progress in designing inhibitors that target the drug-resistant M2 proton channels from the influenza A viruses.

    PubMed

    Wang, Jun; Li, Fang; Ma, Chunlong

    2015-07-01

    Influenza viruses are the causative agents for seasonal influenza, which results in thousands of deaths and millions of hospitalizations each year. Moreover, sporadic transmission of avian or swan influenza viruses to humans often leads to an influenza pandemic, as there is no preimmunity in the human body to fight against such novel strains. The metastable genome of the influenza viruses, coupled with the reassortment of different strains from a wide range of host origins, leads to the continuous evolution of the influenza virus diversity. Such characteristics of influenza viruses present a grand challenge in devising therapeutic strategies to combat influenza virus infection. This review summarizes recent progress in designing small molecule inhibitors that target the drug-resistant influenza A virus M2 proton channels and highlights the contribution of mechanistic studies of proton conductance to drug discovery. The lessons learned throughout the course of M2 drug discovery might provide insights for designing inhibitors that target other therapeutically important ion channels.

  13. Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

    PubMed Central

    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

  14. 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

    2016-07-20

    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.

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

    PubMed Central

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

    2017-01-01

    The Influenza Research Database (IRD) is a U.S. National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Bioinformatics Resource Center dedicated to providing bioinformatics support for influenza virus research. IRD facilitates the research and development of vaccines, diagnostics and therapeutics against influenza virus by providing a comprehensive collection of influenza-related data integrated from various sources, a growing suite of analysis and visualization tools for data mining and hypothesis generation, personal workbench spaces for data storage and sharing, and active user community support. Here, we describe the recent improvements in IRD including the use of cloud and high performance computing resources, analysis and visualization of user-provided sequence data with associated metadata, predictions of novel variant proteins, annotations of phenotype-associated sequence markers and their predicted phenotypic effects, hemagglutinin (HA) clade classifications, an automated tool for HA subtype numbering conversion, linkouts to disease event data and the addition of host factor and antiviral drug components. All data and tools are freely available without restriction from the IRD website at https://www.fludb.org. PMID:27679478

  16. A live-attenuated influenza vaccine for H3N2 canine influenza virus.

    PubMed

    Rodriguez, Laura; Nogales, Aitor; Reilly, Emma C; Topham, David J; Murcia, Pablo R; Parrish, Colin R; Martinez Sobrido, Luis

    2017-04-01

    Canine influenza is a contagious respiratory disease in dogs caused by two subtypes (H3N2 and H3N8) of canine influenza virus (CIV). Currently, only inactivated influenza vaccines (IIVs) are available for the prevention of CIVs. Historically, live-attenuated influenza vaccines (LAIVs) have been shown to produce better immunogenicity and protection efficacy than IIVs. Here, we have engineered a CIV H3N2 LAIV by using the internal genes of a previously described CIV H3N8 LAIV as a master donor virus (MDV) and the surface HA and NA genes of a circulating CIV H3N2 strain. Our findings show that CIV H3N2 LAIV replicates efficiently at low temperature but its replication is impaired at higher temperatures. The CIV H3N2 LAIV was attenuated in vivo but induced better protection efficacy in mice against challenge with wild-type CIV H3N2 than a commercial CIV H3N2 IIV. This is the first description of a LAIV for the prevention of CIV H3N2 in dogs.

  17. 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

  18. Characterization of H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation in eastern China during a 5 year period (1998-2002).

    PubMed

    Zhang, Pinghu; Tang, Yinghua; Liu, Xiaowen; Peng, Daxin; Liu, Wenbo; Liu, Hongqi; Lu, Shan; Liu, Xiufan

    2008-12-01

    In the current study, we characterized H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation during a 5 year period (1998-2002). Phylogenetic analysis of the 8 genes of 11 representative viruses showed that they all shared high similarity to that of the first isolate, A/Chicken/Shanghai/F/1998 (Ck/SH/F/98), and clustered to the same lineages. Furthermore, all 11 viruses had a 9 nt deletion between positions 206 and 214 of the neuraminidase gene. These genetic characteristics strongly suggest that these viruses are descendants of the first isolate. In addition, our study also showed that the H9N2 viruses circulating in the operation during this 5 year period were evolving, as shown by antigenic variations between viruses manifested by reactivity with polyclonal antisera and monoclonal antibodies, by haemagglutination with erythrocytes from different animals, by amino acid differences in haemagglutinin and neuraminidase proteins, and by variation in their ability to replicate in the respiratory and intestinal tract and to be transmitted by aerosol. Phylogenetic analysis revealed that the internal genes from some H5N1 viruses of duck origin clustered together with those from H9N2 virus and that the RNP genes of these H5N1 viruses isolated after 2001 are more closely related to the genes of the Ck/SH/F/98-like H9N2 viruses, indicating more recent reassortment events between these two subtypes of viruses. Continuous surveillance of influenza virus in poultry and waterfowl is critical for monitoring the genesis and emergence of potentially pandemic strains in this region.

  19. 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.

  20. Surveillance of avian influenza viruses in Papua New Guinean poultry, June 2011 to April 2012.

    PubMed

    Jonduo, Marinjho; Wong, Sook-San; Kapo, Nime; Ominipi, Paskalis; Abdad, Mohammad; Siba, Peter; McKenzie, Pamela; Webby, Richard; Horwood, Paul

    2013-01-01

    We investigated the circulation of avian influenza viruses in poultry populations throughout Papua New Guinea to assess the risk to the poultry industry and human health. Oropharyngeal swabs, cloacal swabs and serum were collected from 537 poultry from 14 provinces of Papua New Guinea over an 11-month period (June 2011 through April 2012). Virological and serological investigations were undertaken to determine the prevalence of avian influenza viruses. Neither influenza A viruses nor antibodies were detected in any of the samples. This study demonstrated that avian influenza viruses were not circulating at detectable levels in poultry populations in Papua New Guinea during the sampling period. However, avian influenza remains a significant risk to Papua New Guinea due to the close proximity of countries having previously reported highly pathogenic avian influenza viruses and the low biosecurity precautions associated with the rearing of most poultry populations in the country.

  1. ZMPSTE24 defends against influenza and other pathogenic viruses.

    PubMed

    Fu, Bishi; Wang, Lingyan; Li, Shitao; Dorf, Martin E

    2017-02-28

    Zinc metallopeptidase STE24 (ZMPSTE24) is a transmembrane metalloprotease whose catalytic activity is critical for processing lamin A on the inner nuclear membrane and clearing clogged translocons on the endoplasmic reticulum. We now report ZMPSTE24 is a virus-specific effector that restricts enveloped RNA and DNA viruses, including influenza A, Zika, Ebola, Sindbis, vesicular stomatitis, cowpox, and vaccinia, but not murine leukemia or adenovirus. ZMPSTE24-mediated antiviral action is independent of protease activity. Coimmunoprecipitation studies indicate ZMPSTE24 can complex with proteins of the interferon-induced transmembrane protein (IFITM) family. IFITM proteins impede viral entry, and ZMPSTE24 expression is necessary for IFITM antiviral activity. In vivo studies demonstrate ZMPSTE24-deficient mice display higher viral burdens, enhanced cytokine production, and increased mortality after influenza infection. Collectively, these findings identify ZMPSTE24 as an intrinsic broad-spectrum antiviral protein and provide insights into antiviral defense mechanisms.

  2. One health, multiple challenges: The inter-species transmission of influenza A virus

    PubMed Central

    Short, Kirsty R.; Richard, Mathilde; Verhagen, Josanne H.; van Riel, Debby; Schrauwen, Eefje J. A.; van den Brand, Judith M. A.; Mänz, Benjamin; Bodewes, Rogier

    2015-01-01

    Influenza A viruses are amongst the most challenging viruses that threaten both human and animal health. Influenza A viruses are unique in many ways. Firstly, they are unique in the diversity of host species that they infect. This includes waterfowl (the original reservoir), terrestrial and aquatic poultry, swine, humans, horses, dog, cats, whales, seals and several other mammalian species. Secondly, they are unique in their capacity to evolve and adapt, following crossing the species barrier, in order to replicate and spread to other individuals within the new species. Finally, they are unique in the frequency of inter-species transmission events that occur. Indeed, the consequences of novel influenza virus strain in an immunologically naïve population can be devastating. The problems that influenza A viruses present for human and animal health are numerous. For example, influenza A viruses in humans represent a major economic and disease burden, whilst the poultry industry has suffered colossal damage due to repeated outbreaks of highly pathogenic avian influenza viruses. This review aims to provide a comprehensive overview of influenza A viruses by shedding light on interspecies virus transmission and summarising the current knowledge regarding how influenza viruses can adapt to a new host. PMID:26309905

  3. Avian influenza virus isolates from wild birds replicate and cause disease in a mouse model of infection.

    PubMed

    Driskell, Elizabeth A; Jones, Cheryl A; Stallknecht, David E; Howerth, Elizabeth W; Tompkins, S Mark

    2010-04-10

    The direct transmission of highly pathogenic avian influenza (HPAI) viruses to humans in Eurasia and subsequent disease has sparked research efforts leading to better understanding of HPAI virus transmission and pathogenicity in mammals. There has been minimal focus on examining the capacity of circulating low pathogenic wild bird avian influenza viruses to infect mammals. We have utilized a mouse model for influenza virus infection to examine 28 North American wild bird avian influenza virus isolates that include the hemagglutinin subtypes H2, H3, H4, H6, H7, and H11. We demonstrate that many wild bird avian influenza viruses of several different hemagglutinin types replicate in this mouse model without adaptation and induce histopathologic lesions similar to other influenza virus infections but cause minimal morbidity. These findings demonstrate the potential of wild avian influenza viruses to directly infect mice without prior adaptation and support their potential role in emergence of pandemic influenza.

  4. Pandemic H1N1 influenza virus infection in a Canadian cat

    PubMed Central

    Knight, Cameron G.; Davies, Jennifer L.; Joseph, Tomy; Ondrich, Sarah; Rosa, Brielle V.

    2016-01-01

    A cat was presented for necropsy after being found dead at home. Histologic findings suggested viral pneumonia. Polymerase chain reaction and viral typing revealed influenza A(H1N1)pdm09. This is the first report of influenza in a Canadian cat and highlights the importance of considering influenza virus in the differential diagnosis for feline respiratory distress. PMID:27152036

  5. Influenza A virus infection in zebrafish recapitulates mammalian infection and sensitivity to anti-influenza drug treatment.

    PubMed

    Gabor, Kristin A; Goody, Michelle F; Mowel, Walter K; Breitbach, Meghan E; Gratacap, Remi L; Witten, P Eckhard; Kim, Carol H

    2014-11-01

    Seasonal influenza virus infections cause annual epidemics and sporadic pandemics. These present a global health concern, resulting in substantial morbidity, mortality and economic burdens. Prevention and treatment of influenza illness is difficult due to the high mutation rate of the virus, the emergence of new virus strains and increasing antiviral resistance. Animal models of influenza infection are crucial to our gaining a better understanding of the pathogenesis of and host response to influenza infection, and for screening antiviral compounds. However, the current animal models used for influenza research are not amenable to visualization of host-pathogen interactions or high-throughput drug screening. The zebrafish is widely recognized as a valuable model system for infectious disease research and therapeutic drug testing. Here, we describe a zebrafish model for human influenza A virus (IAV) infection and show that zebrafish embryos are susceptible to challenge with both influenza A strains APR8 and X-31 (Aichi). Influenza-infected zebrafish show an increase in viral burden and mortality over time. The expression of innate antiviral genes, the gross pathology and the histopathology in infected zebrafish recapitulate clinical symptoms of influenza infections in humans. This is the first time that zebrafish embryos have been infected with a fluorescent IAV in order to visualize infection in a live vertebrate host, revealing a pattern of vascular endothelial infection. Treatment of infected zebrafish with a known anti-influenza compound, Zanamivir, reduced mortality and the expression of a fluorescent viral gene product, demonstrating the validity of this model to screen for potential antiviral drugs. The zebrafish model system has provided invaluable insights into host-pathogen interactions for a range of infectious diseases. Here, we demonstrate a novel use of this species for IAV research. This model has great potential to advance our understanding of

  6. 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.

  7. Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells.

    PubMed Central

    Redfield, D C; Richman, D D; Oxman, M N; Kronenberg, L H

    1981-01-01

    Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays. PMID:6265375

  8. Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells

    SciTech Connect

    Redfield, D.C.; Richman, D.D.; Oxman, M.N.; Kronenberg, L.H.

    1981-06-01

    Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays.

  9. 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

    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.

  10. Drug Repurposing Identifies Inhibitors of Oseltamivir-Resistant Influenza Viruses.

    PubMed

    Bao, Ju; Marathe, Bindumadhav; Govorkova, Elena A; Zheng, Jie J

    2016-03-01

    The neuraminidase (NA) inhibitor, oseltamivir, is a widely used anti-influenza drug. However, oseltamivir-resistant H1N1 influenza viruses carrying the H275Y NA mutation spontaneously emerged as a result of natural genetic drift and drug treatment. Because H275Y and other potential mutations may generate a future pandemic influenza strain that is oseltamivir-resistant, alternative therapy options are needed. Herein, we show that a structure-based computational method can be used to identify existing drugs that inhibit resistant viruses, thereby providing a first line of pharmaceutical defense against this possible scenario. We identified two drugs, nalidixic acid and dorzolamide, that potently inhibit the NA activity of oseltamivir-resistant H1N1 viruses with the H275Y NA mutation at very low concentrations, but have no effect on wild-type H1N1 NA even at a much higher concentration, suggesting that the oseltamivir-resistance mutation itself caused susceptibility to these drugs.

  11. 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 ...

  12. Innate immune control and regulation of influenza virus infections

    PubMed Central

    McGill, Jodi; Heusel, Jonathan W.; Legge, Kevin L.

    2009-01-01

    Adaptive immune responses are critical for the control and clearance of influenza A virus (IAV) infection. However, in recent years, it has become increasingly apparent that innate immune cells, including natural killer cells, alveolar macrophages (aMφ), and dendritic cells (DC) are essential following IAV infection in the direct control of viral replication or in the induction and regulation of virus-specific adaptive immune responses. This review will discuss the role of these innate immune cells following IAV infection, with a particular focus on DC and their ability to induce and regulate the adaptive IAV-specific immune response. PMID:19643736

  13. Human and Avian Influenza Viruses Target Different Cells in the Lower Respiratory Tract of Humans and Other Mammals

    PubMed Central

    van Riel, Debby; Munster, Vincent J.; de Wit, Emmie; Rimmelzwaan, Guus F.; Fouchier, Ron A.M.; Osterhaus, Albert D.M.E.; Kuiken, Thijs

    2007-01-01

    Viral attachment to the host cell is critical for tissue and species specificity of virus infections. Recently, pattern of viral attachment (PVA) in human respiratory tract was determined for highly pathogenic avian influenza virus of subtype H5N1. However, PVA of human influenza viruses and other avian influenza viruses in either humans or experimental animals is unknown. Therefore, we compared PVA of two human influenza viruses (H1N1 and H3N2) and two low pathogenic avian influenza viruses (H5N9 and H6N1) with that of H5N1 virus in respiratory tract tissues of humans, mice, ferrets, cynomolgus macaques, cats, and pigs by virus histochemistry. We found that human influenza viruses attached more strongly to human trachea and bronchi than H5N1 virus and attached to different cell types than H5N1 virus. These differences correspond to primary diagnoses of tracheobronchitis for human influenza viruses and diffuse alveolar damage for H5N1 virus. The PVA of low pathogenic avian influenza viruses in human respiratory tract resembled that of H5N1 virus, demonstrating that other properties determine its pathogenicity for humans. The PVA in human respiratory tract most closely mirrored that in ferrets and pigs for human influenza viruses and that in ferrets, pigs, and cats for avian influenza viruses. PMID:17717141

  14. Newcastle disease virus detection and differentiation from avian influenza.

    PubMed

    Miller, Patti J; Torchetti, Mia Kim

    2014-01-01

    Newcastle disease (ND) is a contagious and often fatal disease that affects over 250 bird species worldwide, and is caused by infection with virulent strains of avian paramyxovirus-1 (APMV-1) of the family Paramyxoviridae, genus Avulavirus. Infections of poultry with virulent strains of APMV-1 (Newcastle disease virus) are reportable to the World Organization for Animal Health (OIE). Vaccination of poultry species is a key measure in the control of ND. Other APMV-1 viruses of low virulence, which are not used as vaccines, are also often isolated from wild bird species. The APMV-1 virus, like avian influenza virus (AIV), is a hemagglutinating virus (HA) and able to agglutinate chicken red blood cells (RBC). Because the clinical presentation of ND can be difficult to distinguish from disease caused by AIV, techniques for differential diagnosis are essential, as well as the ability to detect mixed infections. When an HA positive virus is detected from virus isolation, additional assays can be performed to determine which virus is present. Both antigenic and molecular methods are necessary as some virulent ND viruses from cormorants in the USA after 2002 have lost their ability to hemagglutinate chicken RBC and molecular methods are needed for identification.

  15. Preparation of quadri-subtype influenza virus-like particles using bovine immunodeficiency virus gag protein

    SciTech Connect

    Tretyakova, Irina; Hidajat, Rachmat; Hamilton, Garrett; Horn, Noah; Nickols, Brian; Prather, Raphael O.; Tumpey, Terrence M.; Pushko, Peter

    2016-01-15

    Influenza VLPs comprised of hemagglutinin (HA), neuraminidase (NA), and matrix (M1) proteins have been previously used for immunological and virological studies. Here we demonstrated that influenza VLPs can be made in Sf9 cells by using the bovine immunodeficiency virus gag (Bgag) protein in place of M1. We showed that Bgag can be used to prepare VLPs for several influenza subtypes including H1N1 and H10N8. Furthermore, by using Bgag, we prepared quadri-subtype VLPs, which co-expressed within the VLP the four HA subtypes derived from avian-origin H5N1, H7N9, H9N2 and H10N8 viruses. VLPs showed hemagglutination and neuraminidase activities and reacted with specific antisera. The content and co-localization of each HA subtype within the quadri-subtype VLP were evaluated. Electron microscopy showed that Bgag-based VLPs resembled influenza virions with the diameter of 150–200 nm. This is the first report of quadri-subtype design for influenza VLP and the use of Bgag for influenza VLP preparation. - Highlights: • BIV gag protein was configured as influenza VLP core component. • Recombinant influenza VLPs were prepared in Sf9 cells using baculovirus expression system. • Single- and quadri-subtype VLPs were prepared by using BIV gag as a VLP core. • Co-localization of H5, H7, H9, and H10 HA was confirmed within quadri-subtype VLP. • Content of HA subtypes within quadri-subtype VLP was determined. • Potential advantages of quadri-subtype VLPs as influenza vaccine are discussed.

  16. 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.

  17. 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.

  18. Influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza annual report, 2014.

    PubMed

    Sullivan, Sheena G; Chow, Michelle K; Barr, Ian G; Kelso, Anne

    2015-12-31

    The WHO Collaborating Centre for Reference and Research on Influenza in Melbourne is part of the World Health Organization's (WHO) Global Influenza Surveillance and Response System. In 2014 the Centre received a total of 5,374 influenza samples from laboratories primarily in the Asia-Pacific region. Viruses were characterised by their antigenic, genetic and antiviral drug resistance properties. Of the viruses successfully analysed 52% were A(H1N1)pdm09 viruses. The majority of these were antigenically and genetically similar to the WHO recommended reference strain for the 2014 Southern Hemisphere influenza vaccine. Results for A(H3N2) and B/Yamagata viruses suggested that circulating viruses of this subtype and lineage, respectively, had undergone antigenic and/or genetic changes, consistent with the decision by WHO to change recommended strains for the 2015 Southern Hemisphere vaccine. A small number of A(H1N1)pdm09 and B/Victoria viruses had highly reduced inhibition to the neuraminidase inhibitors oseltamivir and zanamivir. The Centre also undertook primary isolation of vaccine candidate viruses directly into eggs. A total of 38 viruses were successfully isolated in eggs, of which 1 (B/Phuket/3073/2013) was included in the 2015 Southern Hemisphere influenza vaccine.

  19. A novel strategy for exploring the reassortment origins of newly emerging influenza virus.

    PubMed

    Tian, Deqiao; Wang, Yumin; Zheng, Tao

    2011-01-01

    In early 2009, new swine-origin influenza A (H1N1) virus emerged in Mexico and the United States. The emerging influenza virus had made global influenza pandemic for nearly one year. To every emerging pathogen, exploring the origin sources is vital for viral control and clearance. Influenza virus is different from other virus in that it has 8 segments, making the segment reassortment a main drive in virus evolution. In exploring reassortment evolution origins of a newly emerging influenza virus, integrated comparing of the origin sources of all the segments is necessary. If some segments have high homologous with one parental strain, lower homologous with another parental strain, while other segments are reverse, can we proposed that this emerging influenza virus may re-assort from the two parental strains. Here we try to explore the multilevel reassortment evolution origins of 2009 H1N1 influenza virus using this method. By further validating the fidelity of this strategy, this method might be useful in judging the reassortment origins of newly emerging influenza virus.

  20. Surveillance of feral cats for influenza A virus in North Central Florida

    PubMed Central

    Gordy, James T.; Jones, Cheryl A.; Rue, Joanne; Crawford, Patti Cynda; Levy, Julie K.; Stallknecht, David E.; Tripp, Ralph A.; Tompkins, Stephen M.

    2011-01-01

    Please cite this paper as: Gordy JT et al. (2012) Surveillance of feral cats for influenza A virus in North Central Florida. Influenza and Other Respiratory Viruses 6(5), 341–347. Background  Transmission of highly pathogenic avian influenza and the recent pandemic H1N1 viruses to domestic cats and other felids creates concern because of the morbidity and mortality associated with human infections as well as disease in the infected animals. Experimental infections have demonstrated transmission of influenza viruses in cats. Objectives  An epidemiologic survey of feral cats was conducted to determine their exposure to influenza A virus. Methods  Feral cat sera and oropharyngeal and rectal swabs were collected from November 2008 through July 2010 in Alachua County, FL and were tested for evidence of influenza A virus infection by virus isolation, PCR, and serological assay. Results and conclusions  No virus was isolated from any of 927 cats examined using MDCK cell or embryonated chicken egg culture methods, nor was viral RNA detected by RT‐PCR in 200 samples tested. However, 0.43% of cats tested antibody positive for influenza A by commercial ELISA. These results suggest feral cats in this region are at minimal risk for influenza A virus infection. PMID:22212818

  1. Attenuation of equine influenza viruses through truncations of the NS1 protein.

    PubMed

    Quinlivan, Michelle; Zamarin, Dmitriy; García-Sastre, Adolfo; Cullinane, Ann; Chambers, Thomas; Palese, Peter

    2005-07-01

    Equine influenza is a common disease of the horse, causing significant morbidity worldwide. Here we describe the establishment of a plasmid-based reverse genetics system for equine influenza virus. Utilizing this system, we generated three mutant viruses encoding carboxy-terminally truncated NS1 proteins. We have previously shown that a recombinant human influenza virus lacking the NS1 gene (delNS1) could only replicate in interferon (IFN)-incompetent systems, suggesting that the NS1 protein is responsible for IFN antagonist activity. Contrary to previous findings with human influenza virus, we found that in the case of equine influenza virus, the length of the NS1 protein did not correlate with the level of attenuation of that virus. With equine influenza virus, the mutant virus with the shortest NS1 protein turned out to be the least attenuated. We speculate that the basis for attenuation of the equine NS1 mutant viruses generated is related to their level of NS1 protein expression. Our findings show that the recombinant mutant viruses are impaired in their ability to inhibit IFN production in vitro and they do not replicate as efficiently as the parental recombinant strain in embryonated hen eggs, in MDCK cells, or in vivo in a mouse model. Therefore, these attenuated mutant NS1 viruses may have potential as candidates for a live equine influenza vaccine.

  2. 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.

  3. Recurrent plastic bronchitis in a child with 2009 influenza A (H1N1) and influenza B virus infection.

    PubMed

    Kim, Sun; Cho, Hwa Jin; Han, Dong Kyun; Choi, Yoo Duk; Yang, Eun Seok; Cho, Young Kuk; Ma, Jae Sook

    2012-09-01

    Plastic bronchitis is an uncommon disorder characterized by the formation of bronchial casts. It is associated with congenital heart disease or pulmonary disease. In children with underlying conditions such as allergy or asthma, influenza can cause severe plastic bronchitis resulting in respiratory failure. A review of the literature showed nine cases of plastic bronchitis with H1N1 including this case. We report a case of a child with recurrent plastic bronchitis with eosinophilic cast associated with influenza B infection, who had recovered from plastic bronchitis associated with an influenza A (H1N1) virus infection 5 months previously. To the best of our knowledge, this is the first case of recurrent plastic bronchitis related to influenza viral infection. If patients with influenza virus infection manifest acute respiratory distress with total lung atelectasis, clinicians should consider plastic bronchitis and early bronchoscopy should be intervened. In addition, management for underlying disease may prevent from recurrence of plastic bronchitis.

  4. Cold adaptation generates mutations associated with the growth of influenza B vaccine viruses.

    PubMed

    Kim, Hyunsuh; Velkov, Tony; Camuglia, Sarina; Rockman, Steven P; Tannock, Gregory A

    2015-10-26

    Seasonal inactivated influenza vaccines are usually trivalent or quadrivalent and are prepared from accredited seed viruses. Yields of influenza A seed viruses can be enhanced by gene reassortment with high-yielding donor strains, but similar approaches for influenza B seed viruses have been largely unsuccessful. For vaccine manufacture influenza B seed viruses are usually adapted for high-growth by serial passage. Influenza B antigen yields so obtained are often unpredictable and selection of influenza B seed viruses by this method can be a rate-limiting step in seasonal influenza vaccine manufacture. We recently have shown that selection of stable cold-adapted mutants from seasonal epidemic influenza B viruses is associated with improved growth. In this study, specific mutations were identified that were responsible for growth enhancement as a consequence of adaptation to growth at lower temperatures. Molecular analysis revealed that the following mutations in the HA, NP and NA genes are required for enhanced viral growth: G156/N160 in the HA, E253, G375 in the NP and T146 in the NA genes. These results demonstrate that the growth of seasonal influenza B viruses can be optimized or improved significantly by specific gene modifications.

  5. Oseltamivir inhibits influenza virus replication and transmission following ocular-only aerosol inoculation of ferrets.

    PubMed

    Belser, Jessica A; Maines, Taronna R; Creager, Hannah M; Katz, Jacqueline M; Tumpey, Terrence M

    2015-10-01

    Ocular exposure to influenza virus represents an alternate route of virus entry capable of establishing a respiratory infection in mammals, but the effectiveness of currently available antiviral treatments to limit virus replication within ocular tissue or inhibit virus spread from ocular sites to the respiratory tract is poorly understood. Using an inoculation method that delivers an aerosol inoculum exclusively to the ocular surface, we demonstrate that oral oseltamivir administration following ocular-only aerosol inoculation with multiple avian and human influenza viruses protected ferrets from a fatal and systemic infection, reduced clinical signs and symptoms of illness, and decreased virus transmissibility to susceptible contacts when a respiratory infection was initiated. The presence of oseltamivir further inhibited influenza virus replication in primary human corneal epithelial cells. These findings provide critical experimental evidence supporting the use of neuraminidase inhibitors during outbreaks of influenza virus resulting in ocular disease or following ocular exposure.

  6. Emergence and development of H7N9 influenza viruses in China.

    PubMed

    Zhu, Huachen; Lam, Tommy Tsan-Yuk; Smith, David Keith; Guan, Yi

    2016-02-01

    The occurrence of human infections with avian H7N9 viruses since 2013 demonstrates the continuing pandemic threat posed by the current influenza ecosystem in China. Influenza surveillance and phylogenetic analyses showed that these viruses were generated by multiple interspecies transmissions and reassortments among the viruses resident in domestic ducks and the H9N2 viruses enzootic in chickens. A large population of domestic ducks hosting diverse influenza viruses provided the precondition for these events to occur, while acquiring internal genes from enzootic H9N2 influenza viruses in chickens promoted the spread of these viruses. Human infections effectively act as sentinels, reflecting the intensity of the activity of these viruses in poultry.

  7. Introduction of Site-Specific Mutations Into the Genome of Influenza Virus

    NASA Astrophysics Data System (ADS)

    Enami, Masayoshi; Luytjes, Willem; Krystal, Mark; Palese, Peter

    1990-05-01

    We succeeded in rescuing infectious influenza virus by transfecting cells with RNAs derived from specific recombinant DNAs. RNA corresponding to the neuraminidase (NA) gene of influenza A/WSN/33 (WSN) virus was transcribed in vitro from plasmid DNA and, following the addition of purified influenza virus RNA polymerase complex, was transfected into MDBK cells. Superinfection with helper virus lacking the WSN NA gene resulted in the release of virus containing the WSN NA gene. We then introduced five point mutations into the WSN NA gene by cassette mutagenesis of the plasmid DNA. Sequence analysis of the rescued virus revealed that the genome contained all five mutations present in the mutated plasmid. The ability to create viruses with site-specific mutations will allow the engineering of influenza viruses with defined biological properties.

  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. 78 FR 9355 - Influenza Viruses Containing the Hemagglutinin From the Goose/Guangdong/1/96 Lineage

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-08

    ... HUMAN SERVICES 42 CFR Part 73 Influenza Viruses Containing the Hemagglutinin From the Goose/ Guangdong/1... from the public regarding whether highly pathogenic avian influenza (HPAI) H5N1 viruses that contain a... concerning highly pathogenic avian influenza (HPAI) H5N1 viruses that contain a hemagglutinin (HA) from...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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.

  12. Genetic and Epidemiological Analysis of Influenza Virus Epidemics in Taiwan during 2003 to 2006▿ †

    PubMed Central

    Jian, Jhih-Wei; Chen, Guang-Wu; Lai, Cheng-Tsung; Hsu, Li-Ching; Chen, Pei-Jer; Kuo, Steve Hsu-Sung; Wu, Ho-Sheng; Shih, Shin-Ru

    2008-01-01

    The genetic characterization of Taiwanese influenza A and B viruses on the basis of analyses of pairwise amino acid variations, genetic clustering, and phylogenetics was performed. A total of 548, 2,123, and 1,336 sequences of the HA1 genes of influenza A virus subtypes H1 and H3 and influenza B virus, respectively, collected during 2003 to 2006 from an island-wide surveillance network were determined. Influenza A virus H3 showed activity during all periods, although it was dominant only in the winters of 2002-2003 and 2003-2004. Instead, influenza B virus and influenza A virus H1 were dominant in the winters of 2004-2005 and 2005-2006, respectively. Additionally, two influenza A virus H3 peaks were found in the summers of 2004 and 2005. From clustering analysis, similar characteristics of high sequence diversity and short life spans for the influenza A virus H1 and H3 clusters were observed, despite their distinct seasonal patterns. In contrast, clusters with longer life spans and fewer but larger clusters were found among the influenza B viruses. We also noticed that more amino acid changes at antigenic sites, especially at sites B and D in the H3 viruses, were found in 2003 and 2004 than in the following 2 years. The only epidemic of the H1 viruses, which occurred in the winter of 2005-2006, was caused by two genetically distinct lineages, and neither of them showed apparent antigenic changes compared with the antigens of the vaccine strain. For the influenza B viruses, the multiple dominant lineages of Yamagata-like strains with large genetic variations observed reflected the evolutionary pressure caused by the Yamagata-like vaccine strain. On the other hand, only one dominant lineage of Victoria-like strains circulated from 2004 to 2006. PMID:18256223

  13. 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.

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

    PubMed Central

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

    2015-01-01

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

  15. 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...

  16. Preparation of Quadri-Subtype Influenza Virus-Like Particles Using Bovine Immunodeficiency Virus Gag Protein

    PubMed Central

    Tretyakova, Irina; Hidajat, Rachmat; Hamilton, Garrett; Horn, Noah; Nickols, Brian; Prather, Raphael O.; Tumpey, Terrence M.; Pushko, Peter

    2015-01-01

    Influenza VLPs comprised of hemagglutinin (HA), neuraminidase (NA), and matrix (M1) proteins have been previously used for immunological and virological studies. Here we demonstrated that influenza VLPs can be made in Sf9 cells by using the bovine immunodeficiency virus gag (Bgag) protein in place of M1. We showed that Bgag can be used to prepare VLPs for several influenza subtypes including H1N1 and H10N8. Furthermore, by using Bgag, we prepared quadri-subtype VLPs, which co-expressed within the VLP the four HA subtypes derived from avian-origin H5N1, H7N9, H9N2 and H10N8 viruses. VLPs showed hemagglutination and neuraminidase activities and reacted with specific antisera. The content and co-localization of each HA subtype within the quadri-subtype VLP were evaluated. Electron microscopy showed that Bgag-based VLPs resembled influenza virions with the diameter of 150-200 nm. This is the first report of quadri-subtype design for influenza VLP and the use of Bgag for influenza VLP preparation. PMID:26529299

  17. Antigenic characterization of H5N1 highly pathogenic avian influenza viruses isolated from poultry in India, 2006-2015.

    PubMed

    Bhat, Sudipta; Nagarajan, Shanmugasundaram; Kumar, Manoj; Murugkar, Harshad V; Kalaiyarasu, Semmannan; Venkatesh, Govindarajulu; Tosh, Chakradhar

    2017-02-01

    Highly pathogenic avian influenza (HPAI) is a major health concern worldwide. In this study, we focused on antigenic analysis of HPAI H5N1 viruses isolated from poultry in India between 2006 and 2015 comprising 25 isolates from four phylogenetic clades 2.2 (1 isolate), 2.2.2.1 (1 isolate), 2.3.2.1a (17 isolates) and 2.3.2.1c (6 isolates). Seven H5N1 isolates from all four clades were selected for production of chicken antiserum, and antigenic analysis was carried out by hemagglutination inhibition (HI) assay. HI data indicated antigenic divergence (6-21 fold reduction in cross-reactivity) between the two recently emerged clades 2.3.2.1a and 2.3.2.1c. These two clades are highly divergent (21-128 fold reduction in HI titre) from the earlier clades 2.2 /2.2.2.1 isolated in India. However, a maximum of 2-fold and 4-fold reduction in cross-reactivity was observed within the isolates of homologous clades 2.3.2.1c and 2.3.2.1a, respectively. The molecular basis of inter-clade antigenic divergence was examined in the haemagglutinin (HA) antigenic sites of the H5N1 virus. Amino acid changes at 8 HA antigenic sites were observed between clades 2.3.2.1a and 2.3.2.1c, whereas 20-23 substitutions were observed between clades 2.3.2.1a/2.3.2.1c and 2.2/2.2.2.1. Therefore, a systematic analysis of antigenic drift of the contemporary field isolates is a pre-requisite for determining the suitable strain(s) for vaccine candidature.

  18. 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

  19. 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.

  20. Highly pathogenic avian influenza viruses and generation of novel reassortants,United States, 2014–2015

    USGS Publications Warehouse

    Dong-Hun Lee,; Justin Bahl,; Mia Kim Torchetti,; Mary Lea Killian,; Ip, Hon S.; David E Swayne,

    2016-01-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses.

  1. 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

  2. Adaptation of pandemic H2N2 influenza A viruses in humans.

    PubMed

    Joseph, Udayan; Linster, Martin; Suzuki, Yuka; Krauss, Scott; Halpin, Rebecca A; Vijaykrishna, Dhanasekaran; Fabrizio, Thomas P; Bestebroer, Theo M; Maurer-Stroh, Sebastian; Webby, Richard J; Wentworth, David E; Fouchier, Ron A M; Bahl, Justin; Smith, Gavin J D

    2015-02-01

    The 1957 A/H2N2 influenza virus caused an estimated 2 million fatalities during the pandemic. Since viruses of the H2 subtype continue to infect avian species and pigs, the threat of reintroduction into humans remains. To determine factors involved in the zoonotic origin of the 1957 pandemic, we performed analyses on genetic sequences of 175 newly sequenced human and avian H2N2 virus isolates and all publicly available influenza virus genomes.

  3. Recombinant Hemagglutinin and Virus-Like Particle Vaccines for H7N9 Influenza Virus

    PubMed Central

    Li, Xiaohui; Pushko, Peter; Tretyakova, Irina

    2015-01-01

    Cases of H7N9 human infection were caused by a novel, avian-origin H7N9 influenza A virus that emerged in eastern China in 2013. Clusters of human disease were identified in many cities in China, with mortality rates approaching 30%. Pandemic concerns were raised, as historically, influenza pandemics were caused by introduction of novel influenza A viruses into immunologically naïve human population. Currently, there are no approved human vaccines for H7N9 viruses. Recombinant protein vaccine approaches have advantages in safety and manufacturing. In this review, we focused on evaluation of the expression of recombinant hemagglutinin (rHA) proteins as candidate vaccines for H7N9 influenza, with the emphasis on the role of oligomeric and particulate structures in immunogenicity and protection. Challenges in preparation of broadly protective influenza vaccines are discussed, and examples of broadly protective vaccines are presented including rHA stem epitope vaccines, as well as recently introduced experimental multi-HA VLP vaccines. PMID:26523241

  4. Universal Detection and Identification of Avian Influenza Virus by Use of Resequencing Microarrays

    DTIC Science & Technology

    2009-04-01

    Society for Microbiology. All Rights Reserved. Universal Detection and Identification of Avian Influenza Virus by Use of Resequencing Microarrays...been, and continue to emerge as, threats to human health. The recent outbreaks of highly pathogenic avian influenza virus in bird populations and the...appearance of some human infections have increased the concern of a possible new influenza pandemic, which highlights the need for broad-spectrum

  5. 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.

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

    DOE PAGES

    Smith, Amber M.; Adler, Frederick R.; Ribeiro, Ruy M.; ...

    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

  7. [Influenza A/H1N1 virus--old and new].

    PubMed

    Bodas, Moran; Davidovich, Nadav; Balicer, Ran D

    2009-08-01

    Swine influenza is a disease known since 1918. Four decades Later, scientists were already isolating the disease-causing agent and learning more about its ability to infect humans. Generally, swine influenza viruses, similarly to avian influenza viruses, do not easily infect humans; however, the viruses' ability to undergo substantial genetic re-assortment enhances the emergence of novel influenza viruses, better capable of infecting and transmitting between humans. Pigs also form good "mixing vessels" for human and avian origin influenza viruses, enabling the emergence of highly virulent influenza strains. Human infection with swine influenza has been recorded in the past, both as sporadic infections and as outbreaks. The best known human swine influenza outbreak took place in Fort Dix (USA) in 1976, concluding in the immunization of almost 45 million U.S. citizens, in a highly controversial immunization program. The current H1N1 (S-OIV) Influenza outbreak was declared by the WHO as an influenza pandemic, setting to rest the lately popular question "when will the next pandemic occur?" and laying the foundations for the evaluation of preparedness plans. There is great importance in data collection and subsequent updating of current procedures and doctrines.

  8. 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

  9. Human Infection with Avian Influenza A(H7N9) Virus - China

    MedlinePlus

    ... reduction Human infection with avian influenza A(H7N9) virus – China Disease outbreak news 18 January 2017 On ... confirmed human infection with avian influenza A(H7N9) virus and on 12 January 2017, the Health Bureau, ...

  10. 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.

  11. Absence of Pandemic H1N1 Influenza A Virus in Fresh Pork

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pigs experimentally infected with pandemic 2009 H1N1 influenza A virus developed respiratory disease; however, there was no evidence for systemic disease to suggest that pork from pigs infected with H1N1 influenza would contain infectious virus. These findings support the WHO recommendation that po...

  12. 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...

  13. [A compact microarray for sub-typing of influenza A virus].

    PubMed

    Riabinin, V A; Kostina, E V; Siniakov, A N

    2013-01-01

    A universal oligonucleotide hybridazation microchip 6 x 5 spot (4 x 4 mm) for influenza A virus subtyping was suggested, functioning on a principle one spot--one subtype. This microchip with additional printing quality control is a prototype of a biosensor for detection of influenza A virus and typing of 15 subtypes of hemagglutinin and 9 subtypes of neuraminidase.

  14. Immune mechanisms associated with enhanced influenza A virus disease versus cross-protection in vaccinated pigs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine associated enhanced respiratory disease (VAERD) has been described in pigs vaccinated with whole-inactivated influenza virus (WIV) following infection with heterologous influenza A virus (IAV). WIV vaccination elicits production of cross-reactive, non-neutralizing antibody to the challenge I...

  15. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Different virucidal activities of hyperbranched quaternary ammonium coatings on poliovirus and influenza virus.

    PubMed

    Tuladhar, Era; de Koning, Martijn C; Fundeanu, Irina; Beumer, Rijkelt; Duizer, Erwin

    2012-04-01

    Virucidal activity of immobilized quaternary ammonium compounds (IQACs) coated onto glass and plastic surfaces was tested against enveloped influenza A (H1N1) virus and nonenveloped poliovirus Sabin1. The IQACs tested were virucidal against the influenza virus within 2 min, but no virucidal effect against poliovirus was found in 6 h.

  18. Third Wave of Influenza A(H7N9) Virus from Poultry, Guangdong Province, China, 2014-2015.

    PubMed

    Xie, Shumin; Jia, Weixin; Lin, Yicun; Xing, Kaixiang; Ren, Xingxing; Qi, Wenbao; Liao, Ming

    2015-09-01

    Fourteen influenza A(H7N9) viruses were isolated from poultry or the environment in live poultry markets in Guangdong Province, China during 2014-2015. Phylogenetic analysis showed that all viruses were descended from viruses of the second wave of influenza A(H7N9) virus infections during 2013. These viruses can be divided into 2 branches.

  19. Third Wave of Influenza A(H7N9) Virus from Poultry, Guangdong Province, China, 2014–2015

    PubMed Central

    Xie, Shumin; Jia, Weixin; Lin, Yicun; Xing, Kaixiang; Ren, Xingxing; Qi, Wenbao

    2015-01-01

    Fourteen influenza A(H7N9) viruses were isolated from poultry or the environment in live poultry markets in Guangdong Province, China during 2014−2015. Phylogenetic analysis showed that all viruses were descended from viruses of the second wave of influenza A(H7N9) virus infections during 2013. These viruses can be divided into 2 branches. PMID:26291620

  20. Impacts of allergic airway inflammation on lung pathology in a mouse model of influenza A virus infection

    PubMed Central

    Kawaguchi, Akira; Ohara, Yuki; Takahashi, Kenta; Sato, Yuko; Ainai, Akira; Nagata, Noriyo; Tashiro, Masato; Hasegawa, Hideki

    2017-01-01

    Influenza A virus is the respiratory pathogen responsible for influenza. Infection by the 2009 pandemic influenza A (H1N1) virus caused severe lower airway inflammation and pneumonia. Asthma is a chronic inflammatory disorder of the airways that affects the entire brachial tree, and was one of the commonest underlying medical conditions among patients hospitalized with the 2009 pandemic influenza virus infection. Although respiratory virus infections are the major causes of asthma exacerbation, the mechanism by which influenza exacerbates asthma is poorly understood. Animal models of disease comorbidity are crucial to understanding host-pathogen interactions and elucidating complex pathologies. Existing murine models of influenza virus infection in asthmatics show that asthmatic mice are highly resistant to influenza virus infection, which contradicts clinical observations in humans. Here, we developed a murine model of influenza virus/asthma comorbidity using NC/Nga mice, which are highly sensitive to allergic reactions such as atopic dermatitis and allergic airway inflammation. This model was then used to examine the impact of allergic airway inflammation on lung pathology in the 2009 pandemic influenza virus infected mice. The results showed that induction of acute allergic airway inflammation in pre-existing influenza virus infection had additive effects on exacerbation of lung pathology, which mirrors findings in human epidemiological studies. In contrast, pre-existing allergic airway inflammation protected from subsequent influenza virus infection, which was compatible with those of previous murine models of influenza virus infection in asthmatic mice. These variable outcomes of this murine model indicate that the temporal relation between allergic airway inflammation and influenza virus infection might play a critical role in asthma and influenza comorbidity. Thus, this murine model will further our understanding of how influenza virus infection affects an

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

    PubMed

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

    2016-10-20

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

  2. Study of influenza A virus in wild boars living in a major duck wintering site.

    PubMed

    Vittecoq, Marion; Grandhomme, Viviane; Simon, Gaëlle; Herve, Séverine; Blanchon, Thomas; Renaud, François; Thomas, Frédéric; Gauthier-Clerc, Michel; van der Werf, Sylvie

    2012-03-01

    Wild birds, which are reservoirs of influenza viruses, are believed to be the original source of new influenza viruses-including highly pathogenic ones-that can be transmitted to domestic animals as well as humans and represent a potential epizootic and/or pandemic threat. Despite increasing knowledge on influenza A virus dynamics in wild birds, the viral circulation in wild boars remains largely unknown. This is of particular interest since pigs can be infected with both human and avian viruses; upon co-infection, they can act as a mixing vessel through reassortment, a mechanism that resulted in the emergence of the pandemic H1N1 virus in 2009. The Camargue (Southern France) appears as an ideal study area to investigate inter-species transmission of influenza A viruses from wild birds and possibly humans to wild boars. Indeed, the important local wild boar population shares wetland use with humans and the largest concentration of wintering ducks in France, that are both susceptible to infection by influenza A viruses. Additionally, wild boars occasionally prey on ducks. We conducted a virological and serological survey on wild boars in the Camargue (Southern France) between September 2009 and November 2010. No influenza A virus was detected in the collected nasal swabs (n=315) and no influenza specific antibodies were observed in the serological samples (n=20). As the study was mainly focused on viral excretion, which is limited in time, we cannot exclude that low or occasional influenza A virus circulation took place during the study period. Although, wild boars did not seem to be a key element in the dynamics of influenza A virus circulation in the Camargue, wild boar influenza A virus infections should be more widely studied to determine if the pattern observed here represents the normal situation or an exceptional one.

  3. 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.

  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. Lethal dissemination of H5N1 influenza virus is associated with dysregulation of inflammation and lipoxin signaling in a mouse model of infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Periodic outbreaks of highly pathogenic avian H5N1 influenza viruses, and the current H1N1 pandemic, highlight the need for a more detailed understanding of influenza virus pathogenesis. The continued emergence of new influenza viruses highlights the need to better understand influenza virus-host in...

  6. Previous infection with a mesogenic strain of Newcastle disease virus affects infection with highly pathogenic avian influenza viruses in chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most important viruses affecting poultry worldwide, but little is known on the interactions between these two viruses when infecting birds. In a previous study we found that infection of chickens with a mesogenic strain of...

  7. Attenuation of a human H9N2 influenza virus in mammalian host by reassortment with an avian influenza virus.

    PubMed

    Saito, T; Lim, W; Tashiro, M

    2004-07-01

    In order to develop a surrogate virus strain for production of an inactivated influenza vaccine against a human H9N2 virus, A/Hong Kong/1073/99 (HK1073: H9N2) was co-infected in embryonated chicken eggs with an apathogenic avian influenza virus, A/Duck/Czechoslovakia/56 (Dk/Cz: H4N6), for gene segment reassortment. Multiple-gene reassortants obtained were examined for replication in mammalian hosts in vitro and in vivo by infecting MDCK cells and by intranasal administration to hamsters, respectively. A 2-6 gene reassortant with both surface glycoproteins of HK1073 origin and the rest of Dk/Cz origin, HK/CZ-13, was shown to replicate poorly in the mammalian hosts both in vivo and in vitro comparing with HK1073, although this reassortant replicated as efficiently as each parental strain in embryonated eggs. No sequence difference was observed in the HA1 region between HK1073 and HK/CZ-13, indicating that the reassortant would be equivalent in its immunogenicity to the parental HK1073 strain when it is used as an inactivated vaccine. A virus strain with attenuation in mammalian hosts is preferable for production of an H9 vaccine, since it should reduce the risk of manufacturing-related infections of employees during the vaccine production. HK/CZ-13 can therefore be a surrogate strain for production of an inactivated vaccine as well as diagnostic antigens in case of a possible future pandemic caused by an HK1073-like H9 influenza virus.

  8. 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.

  9. [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.

  10. Defining the antibody cross-reactome directed against the influenza virus surface glycoproteins.

    PubMed

    Nachbagauer, Raffael; Choi, Angela; Hirsh, Ariana; Margine, Irina; Iida, Sayaka; Barrera, Aldo; Ferres, Marcela; Albrecht, Randy A; García-Sastre, Adolfo; Bouvier, Nicole M; Ito, Kimihito; Medina, Rafael A; Palese, Peter; Krammer, Florian

    2017-04-01

    Infection with influenza virus induces antibodies to the viral surface glycoproteins hemagglutinin and neuraminidase, and these responses can be broadly protective. To assess the breadth and magnitude of antibody responses, we sequentially infected mice, guinea pigs and ferrets with divergent H1N1 or H3N2 subtypes of influenza virus. We measured antibody responses by ELISA of an extensive panel of recombinant glycoproteins representing the viral diversity in nature. Guinea pigs developed high titers of broadly cross-reactive antibodies; mice and ferrets exhibited narrower humoral responses. Then, we compared antibody responses after infection of humans with influenza virus H1N1 or H3N2 and found markedly broad responses and cogent evidence for 'original antigenic sin'. This work will inform the design of universal vaccines against influenza virus and can guide pandemic-preparedness efforts directed against emerging influenza viruses.

  11. 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.

  12. Influenza virus hemagglutinin expression is polarized in cells infected with recombinant SV40 viruses carrying cloned hemagglutinin DNA.

    PubMed

    Roth, M G; Compans, R W; Giusti, L; Davis, A R; Nayak, D P; Gething, M J; Sambrook, J

    1983-06-01

    Primary cell cultures of African Green monkey kidney (AGMK) contain polarized epithelial cells in which influenza virus matures predominantly at the apical surfaces above tight junctions. Influenza virus glycoproteins were found to be localized at the same membrane domain from which the virus budded. When polarized primary AGMK cells were infected with recombinant SV40 viruses containing DNA coding for either an influenza virus H1 or H2 subtype hemagglutinin (HA), the HA proteins were preferentially expressed at the apical surface in a manner identical to that observed in influenza virus-infected cells. Thus, cellular mechanisms for sorting membrane glycoproteins recognize some structural feature of the HA glycoprotein itself, and other viral proteins are not necessary for this process.

  13. 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

  14. 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...

  15. Avian influenza A viruses in birds of the order Psittaciformes: reports on virus isolations, transmission experiments and vaccinations and initial studies on innocuity and efficacy of oseltamivir in ovo.

    PubMed

    Kaleta, E F; Blanco Peña, K M; Yilmaz, A; Redmann, T; Hofheinz, S

    2007-07-01

    Birds of the order Psittaciformes are - besides chickens, turkeys and other birds - also susceptible to infection with avian influenza A viruses (AIV) and succumb following severe disease within one week. Published data prove that various parakeets, amazons, cockatoos, African grey parrots and budgerigars (genera Barnardius, Psittacula, Cacatua, Eolophus, Amazona, Myiopsitta, Psittacus and Melopsittacus) were found dead following natural infections. Natural infections of highly pathogenic avian influenza viruses (HPAIV) of the haemagglutinin subtypes H5 and H7 cause severe disease and high rates of mortality. Experimental transmission studies with AlVs of the subtypes H5 and H7 confirm these data. Viruses of the subtypes H3N8, H4N6, H4N8, H11N6 and H11N8 may cause also clinical signs and occasionally losses in naturally infected psittacine birds. Clinical signs and losses were also noted following experimental infection of budgerigars with a H4N6 virus. In the EU and in other countries, vaccination of exposed exotic and rare birds and poultry is a possible and an acceptable measure to provide protection. Currently, the EU Commission accepts inactivated adjuvanted vaccines whereas in some other countries recently developed vector vaccines are applied. However, birds remain susceptible during the time interval between application of any vaccine and the development of immunity. This critical period can be bridged with antiviral drugs. Our in ovo studies demonstrate that the neuraminidase inhibitor oseltamivir is non-toxic for chicken embryos at concentrations of 0.1, 1.0 and 10.0 mg/kg body weight. These dosages prevented entirely the replication of a HPAIV of the subtype H7N1 when this drug is given shortly prior to, simultaneously or soon after inoculation of chicken embryos with this AIV. Thus, we speculate that exposed valuable birds such as psittacines at risk can be successfully treated.

  16. Simultaneous detection of influenza viruses A and B using real-time quantitative PCR.

    PubMed

    van Elden, L J; Nijhuis, M; Schipper, P; Schuurman, R; van Loon, A M

    2001-01-01

    Since influenza viruses can cause severe illness, timely diagnosis is important for an adequate intervention. The available rapid detection methods either lack sensitivity or require complex laboratory manipulation. This study describes a rapid, sensitive detection method that can be easily applied to routine diagnosis. This method simultaneously detects influenza viruses A and B in specimens of patients with respiratory infections using a TaqMan-based real-time PCR assay. Primers and probes were selected from highly conserved regions of the matrix protein gene of influenza virus A and the hemagglutinin gene segment of influenza virus B. The applicability of this multiplex PCR was evaluated with 27 influenza virus A and 9 influenza virus B reference strains and isolates. In addition, the specificity of the assay was assessed using eight reference strains of other respiratory viruses (parainfluenza viruses 1 to 3, respiratory syncytial virus Long strain, rhinoviruses 1A and 14, and coronaviruses OC43 and 229E) and 30 combined nose and throat swabs from asymptomatic subjects. Electron microscopy-counted stocks of influenza viruses A and B were used to develop a quantitative PCR format. Thirteen copies of viral RNA were detected for influenza virus A, and 11 copies were detected for influenza virus B, equaling 0.02 and 0.006 50% tissue culture infective doses, respectively. The diagnostic efficacy of the multiplex TaqMan-based PCR was determined by testing 98 clinical samples. This real-time PCR technique was found to be more sensitive than the combination of conventional viral culturing and shell vial culturing.

  17. Inactivation of Avian Influenza Virus in Nonpelleted Chicken Feed.

    PubMed

    Toro, H; van Santen, V L; Breedlove, C

    2016-12-01

    Corn stored outside could become contaminated with avian influenza virus (AIV) from wild bird droppings. AIV-contaminated ingredients could pass into the poultry flocks in nonpelleted chicken feed. The efficacy of two disinfectants at inactivating AIV in chicken feed was evaluated. Both Termin-8 (a blend of formaldehyde, propionic acid, terpenes, and surfactant) and Finio (a blend of approved phytochemicals and carboxylic acids) effectively inactivated AIV in chicken feed. Because stability of infectious AIV in chicken feed is limited, we evaluated addition of protein (skim milk powder) to the virus suspension. Protein prolonged the stability of AIV in untreated feed to 24 hr at 24 C. However, both feed disinfectants were able to inactivate the virus in feed even when protected by skim milk powder.

  18. 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

  19. 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

  20. 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.

  1. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection.

    PubMed

    Heaton, Nicholas S; Moshkina, Natasha; Fenouil, Romain; Gardner, Thomas J; Aguirre, Sebastian; Shah, Priya S; Zhao, Nan; Manganaro, Lara; Hultquist, Judd F; Noel, Justine; Sachs, David; Sachs, David H; Hamilton, Jennifer; Leon, Paul E; Chawdury, Amit; Tripathi, Shashank; Melegari, Camilla; Campisi, Laura; Hai, Rong; Metreveli, Giorgi; Gamarnik, Andrea V; García-Sastre, Adolfo; Greenbaum, Benjamin; Simon, Viviana; Fernandez-Sesma, Ana; Krogan, Nevan J; Mulder, Lubbertus C F; van Bakel, Harm; Tortorella, Domenico; Taunton, Jack; Palese, Peter; Marazzi, Ivan

    2016-01-19

    Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.

  2. Influenza: the virus and prophylaxis with inactivated influenza vaccine in “at risk” groups, including COPD patients

    PubMed Central

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

    2007-01-01

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

  3. Intranasal Vaccination with an Engineered Influenza Virus Expressing the Receptor Binding Subdomain of Botulinum Neurotoxin Provides Protective Immunity Against Botulism and Influenza

    PubMed Central

    Li, Junwei; Diaz-Arévalo, Diana; Chen, Yanping; Zeng, Mingtao

    2015-01-01

    Influenza virus is a negative segmented RNA virus without DNA intermediate. This makes it safer as a vaccine delivery vector than most DNA viruses that have potential to integrate their genetic elements into host genomes. In this study, we developed a universal influenza viral vector, expressing the receptor binding subdomain of botulinum neurotoxin A (BoNT/A). We tested the growth characters of the engineered influenza virus in chicken eggs and Madin–Darby canine kidney epithelial cells (MDCK), and showed that it can be produced to a titer of 5 × 106 plaque forming unites/ml in chicken eggs and MDCK cells. Subsequently, mice intranasally vaccinated with the engineered influenza virus conferred protection against challenge with lethal doses of active BoNT/A toxin and influenza virus. Our results demonstrated the feasibility to develop a dual purpose nasal vaccine against both botulism and influenza. PMID:25954272

  4. A novel molecular test for influenza B virus detection and lineage differentiation

    PubMed Central

    Wong, Chloe KS; Tsang, Gary CH; Chan, Kwok-Hung; Li, Olive TW; Peiris, Malik; Poon, Leo LM

    2014-01-01

    Contemporary influenza B viruses are classified into two groups known as Yamagata and Victoria lineages. The co-circulation of two viral lineages in recent years urges for a robust and simple diagnostic test for detecting influenza B viruses and for lineage differentiation. In this study, a SYBR green-based asymmetric PCR assay has been developed for influenza B virus detection. Apart from identifying influenza B virus, the assay contains sequence-specific probes for lineage differentiation. This allows identifying influenza B virus and detecting influenza B viral lineage in a single reaction. The test has been evaluated by a panel of respiratory specimens. Of 108 Influenza B virus-positive specimens, 105 (97%) were positive in this assay. None of the negative control respiratory specimens were positive in the test (N=60). Viral lineages of all samples that are positive in the assay (N=105) can also be classified correctly. These results suggest that this assay has a potential for routine influenza B virus surveillance. PMID:24760697

  5. Adaptation of an H7N7 equine influenza A virus in mice.

    PubMed

    Shinya, Kyoko; Watanabe, Shinji; Ito, Toshihiro; Kasai, Noriyuki; Kawaoka, Yoshihiro

    2007-02-01

    Wild waterfowl are a reservoir for influenza A viruses, which can be transmitted from these birds to other animal species. Occasionally, influenza A viruses are transmitted to other animal species from animals other than wild waterfowl, e.g. an equine influenza virus has been transmitted to dogs and caused outbreaks. To understand the molecular mechanism by which influenza A viruses adapt to a new animal species, the molecular changes involved in the adaptation of an H7N7 equine influenza A virus were studied in mice. Mutations in the mouse-adapted virus mapped to one amino acid change in the PA protein, one in PB2 and two in PB1. Of these mutations, the Glu-to-Lys substitution at position 627 of PB2 (PB2-E627K) increased virulence appreciably. To understand the mechanism of this increased virulence, a recombinant virus expressing a reporter green fluorescent protein was constructed, thus enabling the effect of this mutation on viral protein expression to be tested in the context of virus replication in situ. It was found that the PB2-E627K substitution in this equine virus contributed to increased viral protein expression and virus replication in mouse cells and enhanced brain invasiveness in mice. These results demonstrate that the importance of the PB2-E627K substitution for mouse adaptation, which was identified previously in human H5N1 isolates, extends to equine influenza A virus.

  6. Influenza A Virus Polymerase Is a Site for Adaptive Changes during Experimental Evolution in Bat Cells

    PubMed Central

    Poole, Daniel S.; Yú, Shuǐqìng; Caì, Yíngyún; Dinis, Jorge M.; Müller, Marcel A.; Jordan, Ingo; Friedrich, Thomas C.; Kuhn, Jens H.

    2014-01-01

    ABSTRACT The recent identification of highly divergent influenza A viruses in bats revealed a new, geographically dispersed viral reservoir. To investigate the molecular mechanisms of host-restricted viral tropism and the potential for transmission of viruses between humans and bats, we exposed a panel of cell lines from bats of diverse species to a prototypical human-origin influenza A virus. All of the tested bat cell lines were susceptible to influenza A virus infection. Experimental evolution of human and avian-like viruses in bat cells resulted in efficient replication and created highly cytopathic variants. Deep sequencing of adapted human influenza A virus revealed a mutation in the PA polymerase subunit not previously described, M285K. Recombinant virus with the PA M285K mutation completely phenocopied the adapted virus. Adaptation of an avian virus-like virus resulted in the canonical PB2 E627K mutation that is required for efficient replication in other mammals. None of the adaptive mutations occurred in the gene for viral hemagglutinin, a gene that frequently acquires changes to recognize host-specific variations in sialic acid receptors. We showed that human influenza A virus uses canonical sialic acid receptors to infect bat cells, even though bat influenza A viruses do not appear to use these receptors for virus entry. Our results demonstrate that bats are unique hosts that select for both a novel mutation and a well-known adaptive mutation in the viral polymerase to support replication. IMPORTANCE Bats constitute well-known reservoirs for viruses that may be transferred into human populations, sometimes with fatal consequences. Influenza A viruses have recently been identified in bats, dramatically expanding the known host range of this virus. Here we investigated the replication of human influenza A virus in bat cell lines and the barriers that the virus faces in this new host. Human influenza A and B viruses infected cells from geographically and

  7. Long-Term Shedding of Influenza Virus, Parainfluenza Virus, Respiratory Syncytial Virus and Nosocomial Epidemiology in Patients with Hematological Disorders.

    PubMed

    Lehners, Nicola; Tabatabai, Julia; Prifert, Christiane; Wedde, Marianne; Puthenparambil, Joe; Weissbrich, Benedikt; Biere, Barbara; Schweiger, Brunhilde; Egerer, Gerlinde; Schnitzler, Paul

    2016-01-01

    Respiratory viruses are a cause of upper respiratory tract infections (URTI), but can be associated with severe lower respiratory tract infections (LRTI) in immunocompromised patients. The objective of this study was to investigate the genetic variability of influenza virus, parainfluenza virus and respiratory syncytial virus (RSV) and the duration of viral shedding in hematological patients. Nasopharyngeal swabs from hematological patients were screened for influenza, parainfluenza and RSV on admission as well as on development of respiratory symptoms. Consecutive swabs were collected until viral clearance. Out of 672 tested patients, a total of 111 patients (17%) were infected with one of the investigated viral agents: 40 with influenza, 13 with parainfluenza and 64 with RSV; six patients had influenza/RSV or parainfluenza/RSV co-infections. The majority of infected patients (n = 75/111) underwent stem cell transplantation (42 autologous, 48 allogeneic, 15 autologous and allogeneic). LRTI was observed in 48 patients, of whom 15 patients developed severe LRTI, and 13 patients with respiratory tract infection died. Phylogenetic analysis revealed a variety of influenza A(H1N1)pdm09, A(H3N2), influenza B, parainfluenza 3 and RSV A, B viruses. RSV A was detected in 54 patients, RSV B in ten patients. The newly emerging RSV A genotype ON1 predominated in the study cohort and was found in 48 (75%) of 64 RSV-infected patients. Furthermore, two distinct clusters were detected for RSV A genotype ON1, identical RSV G gene sequences in these patients are consistent with nosocomial transmission. Long-term viral shedding for more than 30 days was significantly associated with prior allogeneic transplantation (p = 0.01) and was most pronounced in patients with RSV infection (n = 16) with a median duration of viral shedding for 80 days (range 35-334 days). Long-term shedding of respiratory viruses might be a catalyzer of nosocomial transmission and must be considered for

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

    PubMed

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

    2011-10-01

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

  9. When animal viruses attack: SARS and avian influenza.

    PubMed

    Lee, Paul J; Krilov, Leonard R

    2005-01-01

    SARS and avian influenza have many common features. They both arose in Asia and originated from animal viruses. They both have the potential to become pandemics because human beings lack antibodies to the animal-derived antigens present on the viral surface and rapid dissemination can occur from the relative ease and availability of high speed and far-reaching transportation methods. Pediatricians, in particular, should remain alert about the possibility of pandemic illnesses in their patients. Annual rates of influenza in children may be 1.5 to 3 times those in the adult population, and infection rates during a community epidemic may exceed 40% in preschool-aged children and 30% in school-aged children. Infected children also play a central role in disseminating influenza, as they are the major point of entry for the virus into the household, from which adults spread disease into the community. Of course, children younger than 24 months also are at high risk for complications from influenza. A 1999 Centers for Disease Control and Prevention projection of an influenza pandemic in the US paints a grim picture: 89,000 to 207,000 deaths, 314,000 to 734,000 hospitalizations, 18 million to 42 million outpatient visits, and 20 million to 47 million additional illnesses, at a cost to society of at least dollars 71.3 billion to dollars 166.5 billion. High-risk patients (15% of the population) would account for approximately 84% of all deaths. Although SARS has been kind to the pediatric population so far, there are no guarantees that future outbreaks would be as sparing. To aid readers in remaining up-to-date with SARS and avian influenza, some useful websites are listed in the Sidebar. Two masters of suspense, Alfred Hitchcock and Stephen King, may have been closer to the truth than they ever would have believed. Both birds and a super flu could bring about the end of civilization as we know it. But all is not lost--to paraphrase Thomas Jefferson, the price of health is

  10. 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.

  11. Uncomplicated Cystitis in an Adult Male Following Influenza B Virus Infection

    PubMed Central

    Allen, Robert J.; Koutsakos, Marios; Hurt, Aeron C.; Kedzierska, Katherine

    2017-01-01

    Patient: Male, 31 Final Diagnosis: Uncomplicated cystitis Symptoms: Cough • dysuria • fever • hematuria Medication: — Clinical Procedure: — Specialty: Infectious Diseases Objective: Unusual clinical course Background: Influenza B viruses cause seasonal epidemics of respiratory illness, circulating concurrently with influenza A viruses. However, virological and clinical knowledge of influenza B viruses is less well advanced than for influenza A, and in particular, complications associated with influenza B infection are not as commonly reported. Complications of influenza B infection predominantly include neurological and musculoskeletal pathologies, while a review of the literature shows that bacterial infections associated with influenza B viruses often involve Gram-positive organisms, with a smaller subset featuring Gram-negative species. Case Report: In this case report we highlight an uncomplicated infection of the urinary tract by Escherichia coli immediately following influenza B infection, in an otherwise healthy adult white male with no prior history of urinary tract infection or structural abnormalities of the renal tract. Conclusions: Bacterial infections complicating influenza B infection may include organisms not commonly associated with the respiratory system, such as Escherichia coli. In addition, bacterial complications of influenza B infection may affect non-respiratory systems, including the genitourinary tract. PMID:28223680

  12. High permissivity of human HepG2 hepatoma cells for influenza viruses.

    PubMed

    Ollier, Laurence; Caramella, Anne; Giordanengo, Valérie; Lefebvre, Jean-Claude

    2004-12-01

    Human HepG2 hepatoma cells are highly permissive for influenza virus type A and type B, even without the addition of trypsin, and they exhibit a marked cytopathic effect. This property greatly facilitates the primary isolation of influenza viruses. Virus replication was significantly reduced by the plasmin(ogen)-specific inhibitor tranexamic acid, and this suggests a potential role played by the plasminogen/tissue plasminogen activator complex at the surface of HepG2 cells. This might represent a new approach for study of the interrelations of this complex with influenza viruses.

  13. High Permissivity of Human HepG2 Hepatoma Cells for Influenza Viruses

    PubMed Central

    Ollier, Laurence; Caramella, Anne; Giordanengo, Valérie; Lefebvre, Jean-Claude

    2004-01-01

    Human HepG2 hepatoma cells are highly permissive for influenza virus type A and type B, even without the addition of trypsin, and they exhibit a marked cytopathic effect. This property greatly facilitates the primary isolation of influenza viruses