Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: January 28, 2009
Publication Date: April 5, 2009
Citation: Sarmento, L., Pantin Jackwood, M.J., Wasilenko, J.L. 2009. The role of NS protein in the pathogenicity of HPAI H5N1 viruses in ducks [abstract]. 7th International Symposium on Avian Influenza, April 5-9, 2009, Athens, Georgia. p. 87. Technical Abstract: Until 2002, highly pathogenic avian influenza (HPAI) H5N1 viruses caused no disease or only mild respiratory infections in ducks. Since then, new viruses have emerged that cause systemic disease and high mortality in ducks and other waterfowl. Studies on HPAI virus pathogenicity in ducks have been limited and there is no clear explanation of why the increase in pathogenicity observed with some HPAI H5N1 viruses in ducks. In order to determine which avian influenza (AI) virus genes contribute to increased virulence in ducks, single gene reassortant viruses were generated. It is known that the non-structural (NS) protein has the ability to suppress interferon in mammalian systems and in chickens affecting viral pathogenesis. Exchanging the NS1 genes from A/Ck/HK/220/97 (a virus that produces no disease in ducks) and A/Dk/VN/201/05 (a very virulent virus for ducks) in the rEgret background (a recombinant virus derived from A/Egret/HK/757.2/02), resulted in differences in mean death times (MDTs) compared to infection with the rEgret virus in ducks. However, the exchange of this particular gene was not enough to induce complete change in pathogenicity of the parent virus, indicating the most likely involvement of other viral genes.