ABSTRACT
A H5N2 subtype avian influenza virus isolated from goose belongs to highly pathogenic avian influenza virus, and the intravenous pathogenicity indexes (IVPI) =2.99. But ducks are not sensitive to this isolated influenza virus. The virus can infect mouse but only replicates in lung and has no pathogenicity. HA and NA gene of this isolated strain share 99.4% and 99.8% nucleotide sequence identity to the HA gene of A/chicken/Hubei/ 489/2004 (H5N1) and the NA gene of A/chicken/Jilin/53/01 (H9N2), and share 99.3% and 99.6% amino acid sequence identity to the HA protein of A/chicken/Hubei/489/2004 (H5N1), A/swan/Guangxi/307/2004 (H5N1), A/wild duck/ Guangdong/314/2004(H5N1), A/chicken/Henan/210/2004(H5N1) and the NA protein of A/chicken/ Jilin/53/01 (H9N2). There are several continuous basic amino acids (-RRRKKR-) at the cleavage site of HA protein. Phylogenetic trees analysis of HA and NA gene suggests that the isolated influenza virus probably originated from the reassortment of H5N1 and H9N2 subtype influenza virus.