2018–2019年安徽地区H9N2亚型禽流感病毒进化分析

EVOLUTIONARY ANALYSIS OF H9N2 AVIAN INFLUENZA VIRUSES ISOLATED IN ANHUI PROVINCE FROM 2018 TO 2019

为调查H9N2亚型禽流感病毒(AIV)在安徽地区养殖场中的流行变异情况,本研究采用RT-PCR方法对2018-2019年采集自安徽养殖场的2763份样品进行AIV的检测,并采用鸡胚接种分离病毒的方法从核酸阳性样品中进行病毒分离。结果显示:从阳性样品分离获得5株H9N2毒株;5株H9N2分离株的HA裂解位点为PSRSSRGLF,符合低致病性禽流感病毒的序列特征,HA受体结合位点234位氨基酸为亮氨酸(Leu),具有与哺乳动物唾液酸受体结合的特征,HA蛋白在313位具有潜在的糖基化位点,M2蛋白发生S31N突变;5株H9N2分离株的HA、NA基因属于Y280-like分支,PB2、M基因属于G1-like分支,PB1、PA、NP、NS基因属于F/98-like分支。本研究结果为禽流感疫苗研发提供了流行病学参考。

To investigate the epidemiology and variation of H9N2 subtype Avian influenza virus(AIV)in Anhui province,total 2763 samples were collected from chicken farms during 2018 to 2019 and tested for AIV nucleic acids by RT-PCR and positive samples were inoculated into chicken embryonated eggs for virus isolation.Five H9N2 isolates were obtained and sequenced for genomic analysis.The results showed that the HA cleavage site of these five H9N2 isolates was PSRSSRGLF,which matched the characteristics of a low pathogenic AIV.The amino acid at position 234 of the HA receptor binding site was Leu,which had the activity to bind to mammalian sialic acid receptors.All five H9N2 isolates had potential glycosylation site at position 313 of HA protein.S31N mutation was also found in the M2 protein of these H9N2 isolates.Phylogenetic analysis showed that these H9N2 isolates belonged to the branch of Y280-like based on HA and NA genes,to the branch of G1-like,PB2 based on M genes and to the branch of F/98-like based on NP,NS,PA and PB1 genes.This study provided an epidemiological reference for designing AIV vaccine.