2010—2014年山东H9N2亚型禽流感病毒分离鉴定及HA和NA基因序列分析

Virus Isolation and Genetic Analysis of HAand NA Genes of H9N2 AIVs Isolated from Shandong Province from 2010 to 2014

旨在了解山东地区H9N2亚型禽流感病毒(AIV)的流行和遗传变异情况,为该地区H9N2亚型禽流感的防制提供依据。通过鸡胚接种的方法从山东省分离到1 296株H9N2AIV,并选取40株对其进行HA和NA基因的扩增、测序及遗传进化分析。结果显示,2013年H9N2AIV的分离率最高,达42.30%;40株病毒的HA和NA的核苷酸序列同源性及推导的氨基酸相似性均在90%以上;HA裂解位点序列为PSRSSR↓GLF,NA颈部缺失3个氨基酸;HA和NA均存在糖基化位点的缺失和新的糖基化位点出现;大部分毒株发生了易于感染人型受体的突变;演化分析表明40株病毒的HA和NA基因均属于Y280-like亚分支。结果提示,H9N2AIV在山东省各地区普遍流行且在2013年达到高峰,所有毒株均符合低致病性禽流感病毒的分子特征,并且具有结合哺乳动物唾液腺受体的能力,因此应密切关注H9N2病原出现的新变化,制定相应的防控措施。

In order to explore the epidemiological and genetic character of the H9N2 viruses,a long-term surveillance have been conducted in Shandong province.One thousand two hundred and ninety six strains of H9N2 virus were isolated from clinical samples,which were collected in chicken farms and LBMs,and the HAand NAgenes of 40 strains selected were amplified and sequenced.The HAand NAgenes of these viruses shared more than 90%identity at the nucleotide level and amino acid level;most viruses carried the amino acid sequence PSRSSR↓GLF at the HA cleavage site and a 3-amino-acid deletion in the NA stalk;new potential N-glycosylation sites were found in the HA and NA in some viruses;the Q226L（H3numbering）mutation was detected inall viruses at the receptor-binding pocket of HA;phylogenetic analysis showed that the HA and NA belong to the Y280-like sublineage.The H9N2 influenza virus was widely circulating in poultry farms of Shandong province,and reached peak in 2013;all of isolates preferentially bound to the human-like receptor,but still have the characteristic of low-pathogenic AIV.So,keeping monitoring and controlling H9N2 virus is necessary.