Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 7, 2010
Publication Date: July 21, 2010
Citation: Wasilenko, J.L., Pantin Jackwood, M.J., Sarmento, L., Cagle, C.A. 2010. Determinants of pathogenicity of H5N1 highly pathogenic avian influenza viruses in ducks [abstract]. American Society for Virology 29th Annual Meeting, July 17-21, 2010, Bozeman, Montana. p. 279. Technical Abstract: Ducks have been implicated in the dissemination and evolution of the H5N1 highly pathogenic avian influenza (HPAI) viruses. The pathogenicity of H5N1 HPAI viruses in domestic ducks has increased over time with some viruses producing 100% mortality in very short time. The determinants of pathogenicity of H5N1 HPAI viruses have been well studied in mammals; however, the factors contributing to increased H5N1 HPAI virus pathogenicity in ducks have not been well characterized. In order to determine which avian influenza viral genes are contributing to the increased virulence observed with some H5N1 HPAI viruses we used reverse genetics to generate single-gene reassortant viruses with genes from A/chicken/Indonesia/7/03, a virus that produces mild disease in ducks, and A/duck/Vietnam/201/05 H5N1 virus, a very virulent virus for ducks. Exchange of the A/duck/Vietnam/201/05 hemagglutinin (HA) gene in the A/chicken/Indonesia/7/03 background resulted in increased mortality, decreased mean death times and increased distribution of viral antigen staining in the tissues of the infected ducks. Differences in the HA genes were found in the receptor binding sites, and hemadsorption assays showed that the more virulent recombinant virus bound more readily to the red blood cells than the less virulent backbone virus. This study shows that changes in the HA gene could be the cause of the increased pathogenicity of H5N1 HPAI viruses in ducks.