【摘要】 本研究于2013年从广东某发病鸡场分离到一株H9N2亚型AIV,命名为A/chicken/Guangdong/LG1/2013。对病毒进行全基因组克隆测序和进化分析,其HA基因裂解基序为333PSRSSR↓GLF341,呈典型低致病性AIV分子特征。其HA基因发生Q226L突变和A316S突变,NA基因出现第63～65位氨基酸缺失。该病毒株HA、NA和NS基因属于类BJ/1/94分支,PB2属于类SD/H/09分支,PB1、PA、NP基因属于类SH/F/98分支,M基因属于类HK/G1/97分支,该基因型在广东地区未见报道,其内部基因与H7N9亚型人流感病毒SH/02/2013株核苷酸同源性在95.6%～98.6%之间。本研究表明我国H9N2亚型AIV呈现遗传演化的多样性及基因重组的复杂性,对该亚型病毒的监测和研究具有重要的兽医和公共卫生意义。更多还原

【Abstract】 To investigate the genetic and evolutionary characteristics of H9N2 avian influenza virus(AIV) in poultry flocks in Guangdong province,an H9N2 AIV was isolated and designated A/chicken/Guangdong/LG1/2013(CK/GD/LG1/13).The phylogenetic and molecular characteristics of the isolate were analyzed.The HA cleavage sequence of the isolate possessed the 333 PSRSSR↓GLF 341 motif,suggesting that this isolate was of a low pathogenicity in avian species.However,this isolate had an A 316 S mutation at the HA cleavage site and a 3-amino-acid deletion at position 63 to 65 on the NA stalk,which indicated an enhanced virulence in chickens and mice.Furthermore,CK/GD/LG1/13 also had the Q 226 L mutation at HA receptor-binding site which could increase the binding of the virus to human-type receptors,SAα-2,6.The HA,NA and NS genes of the isolate belong to BJ/1/94-like lineage.The PB2 belongs to H-like and the M gene belongs to G1-like lineage,while the PB1,PA and NP genes belong to F98-like lineage.The genotype of the isolate in poultry flocks in Guangdong province has never been reported before.It is noteworthy that six internal genes of the isolate share 95.6%-98.6% nucleotide identities with that of SH/1/2013(H7N9).The findings of mammalian-adapting mutations and probable efficient replication in mammalians in this novel AIV are caused for concern.This study demonstrated that H9N2 virus in south China had undergone extensive evolution and reassortment to generate a novel genotype,suggesting that continuous surveillance of H9N2 viruses possesses significant veterinary and public health benefit.更多还原