Detection And Sequence Analysis Of Influenza A Virus Strains From Feral Ducks Wingting In Wetlands In Jiangsu Province

256 cloacal swabs from 256 feral ducks including 13 types wintering in Hongze Lake, Gaoyou Lake and Yangcheng wetlands Reserve in Jiangsu province collected from October 2004 to March 2005 were checked for the presence of influenza A viruses using RT-PCR with primers specific for conserved sequences of the NP gene of viruses origin from avian, human, swine and equine. Results suggest that the prevalence of influenza viruses is up to 52.34%. The prevalence is over 80% in Mallard, Baikal Teal, Smew and Common shelduck. These findings reveal that positive rate of influenza viruses is high in feral ducks in these areas. 23 isolates have been obtained. This is the first report about influenza viruses in feral ducks in Jiangsu province.Nucleiotide sequences anlysis of NP gene (330bp) suggest homology between A/Common Teal/XuYi/04 and H3N2 influenza viruses from swine and human is 95%; homology between spdkYC1905 and H5N1 influenza viruses which infected 18 human in 1997 in Hong Kong is 96%; and the identity between spdkXy2305 and HPAIV H5N1 that caused outbreaks in poutry in Southeast Asia in 2004 is 99%, and spdkXy2505 is closely related to H5N1 influenza viruses derived from human, ducks, swine, chicken, quails in Hong Kong and Guangxi in our country. This suggest that these viruses maybe a great threat to public and poultry health.None of the GenBank sequence data for known avian influenza genomes completely mathed the HA, PB2, NP, M, NS genes of isolate A/mallard/xuyi/G8/H11N?, and analysis of these sequences revealed that this isolate maybe derive from the viruses from Europe and southerneast of China.Analysis of M gene nucleotide sequences from ten isolates suggest that these isolates can be divided in two clades: one clade which is closely related to the LPAIV tkIt02 includes M gene of seven isolates: maGY3305, btHZ1605, spdkYC1905, maXY804, spdkXy2505, btXY1805, gsdHZ705; and the other clade includes btXY1705 , spdkXy2305, maGY3105, those are closely related to HPAIV H5N1, such as midkJx05(H5N1) which isolated from apparently healthy migratory...