Samples of chicken,duck,quail,and pigeon were collected from Jiangsu,Anhui,and Hebei in 2009-2011,and sixteen H9N2 subtype isolates of avian influenza virus(AIV) were identified.The eight full-length genes of 16 AIV isolates were amplified by RT-PCR and sequenced.Genome sequence analysis showed that the amino acid motif of cleavage sites in the HA gene was P-S-R/K-S-S-R,which was consistent with the characterization of the LPAIV,and the Leucine(L) at the amino acid position 226 in the HA genes of all isolat...