Title
Pathogenicity and vaccine efficacy of different clades of Asian H5N1 avian influenza A viruses in domestic ducks
Author(s)
Kim, J.-K.; Seiler, P.; Forrest, H.L.; Khalenkov, A.M.; Franks, J.; Kumar, M.; Karesh W.B., Gilbert, M.; Sodnomdarjaa, R.; Douangngeun, B.; Govorkova, E.A.; Webster, R.G.
Published
2008
Publisher
Journal of Virology
Published Version DOI
https://doi.org/10.1128/JVI.01176-08
Abstract
Waterfowl represent the natural reservoir of all subtypes of influenza A viruses, including H5N1. Ducks are especially considered major contributors to the spread of H5N1 influenza A viruses because they exhibit diversity in morbidity and mortality. Therefore, as a preventive strategy against endemic as well as pandemic influenza, it is important to reduce the spread of H5N1 influenza A viruses in duck populations. Here, we describe the pathogenicity of dominant clades (clades 1 and 2) of H5N1 influenza A viruses circulating in birds in Asia. Four representatives of dominant clades of the viruses cause symptomatic infection but lead to different profiles of lethality in domestic ducks. We also demonstrate the efficacy, cross-protectiveness, and immunogenicity of three different inactivated oil emulsion whole-virus H5 influenza vaccines (derived by implementing reverse genetics) to the viruses in domestic ducks. A single dose of the vaccines containing 1 µg of hemagglutinin protein provides complete protection against a lethal A/Duck/Laos/25/06 (H5N1) influenza virus challenge, with no evidence of morbidity, mortality, or shedding of the challenge virus. Moreover, two of the three vaccines achieved complete cross-clade or cross-subclade protection against the heterologous avian influenza virus challenge. Interestingly, the vaccines induce low or undetectable titers of hemagglutination inhibition (HI), cross-HI, and/or virus neutralization antibodies. The mechanism of complete protection in the absence of detectable antibody responses remains an open question. Copyright © 2008, American Society for Microbiology. All Rights Reserved.
Keywords
inactivated virus vaccine; influenza vaccine; neutralizing antibody; placebo; virus hemagglutinin; immunological adjuvant; inactivated vaccine; oil; virus antibody; animal experiment; animal model; antibody response; antibody titer; article; Asia; avian influenza; cladistics; cloaca; controlled study; dose response; drug dose comparison; drug efficacy; duck; emulsion; immunogenicity; influenza vaccination; Influenza virus A H5N1; lethality; morbidity; mortality; nonhuman; pathogenicity; priority journal; serology; trachea; virus hemagglutination; virus shedding; animal; blood; domestic animal; hemagglutination inhibition test; immunology; survival; virology; Anas; Anas platyrhynchos; Anatidae; Aves; Avian influenza virus; Influenza A virus; Orthomyxoviridae; Adjuvants, Immunologic; Animals; Animals, Domestic; Antibodies, Viral; Asia; Cloaca; Ducks; Hemagglutination Inhibition Tests; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza Vaccines; Oils; Survival Analysis; Trachea; Vaccines, Inactivated; Virus Shedding

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PUB10505