Study on the genetic characteristics of the avian influenza virus strain A/Zhejiang/16/2006]

To study the genetic characteristics of avian influenza virus strain A/Zhejiang/ 16/2006 which was isolated from the case first reported in Zhejiang province.Complete genome of A/Zhejiang/16/2006 including eight segments were sequenced and compared on the genetic homogeneity with sequences of the similar strains provided through domestic and overseas sources.There were 11 amino acids showing differences on HA between A/Zhejiang/16/2006 and the H5N1 isolates of neighboring countries, but these differences had not affected the stability of glycosylation sites. In the NA region, 20 amino acids located in the 49th to 68th position were found absent in the isolates obtained after 1997. Eight segments of H5N1 isolates, circulating in the mainland of China in the recent years, formed a separate branch compared to the strains in neighboring countries and there was also obviously different from the strains isolated in Hong Kong and Guangzhou in 1996 and 1997. However, several Chinese strains were close to the Hong Kong strains isolated in 1997 but diffferent from the current strains in the phylogenetic tree.The influenza virus strain A/Zhejiang/16/2006 formed a separate branch with the strains isolated in the mainland of China in the past years but it presented an obvious difference with the isolates from the neighboring countries.