Genetic Characterization of the Entire Genome of an H9N2 Avian Influenza Virus A/Chicken/Shanghai/F/98
H9N2亚型禽流感病毒基因组全长序列测定和各基因的遗传分析

Eight full-length genes of an H9N2 subtype avian influenza virus A/Chicken/Shanghai/F/98(H9N2), were amplified by RT-PCR and rapid amplification of cDNA ends (RACE) and sequenced. The results of phylogenetic analysis showed that A/Chicken/Shanghai/F/98 was entirely different from Quail/Hong Kong/G1/97 which was directly related to human infection with avian influenza virus in Hong Kong, whereas its HA, NA, M and NS genes belonged to A/Chicken/Beijing/1/94-like sublineage with the nucleotide homology of 96.7%, 96.4%, 97.5% and 98.0% respectively. The homology of NA gene between A/Chicken/Shanghai/F/98 and A/Duck/Hong Kong/Y280/97 was 97.4% and they both lost 9 nucleotides between nt 205 to 206. However, the PB2, PB1, PA, NP genes did not show any close relationship with those of the three known sublineages and the later three didn't share immediate ancestors with available isolates whose sequences had been reported. Therefore, A/Chicken/Shanghai/F/98 is a product of natural reassortment between H9N2 avian influenza viruses from different sublineages.