青海湖一株野鸟源H5N1亚型禽流感病毒核酸检测及其基因组序列特性分析

Nucleic Acid Detection and Genomic Sequence Analysis of One H5N1 Avian Influenza Virus From Wide Birds Around Qinghai Lake

2022年8月,青海省刚察县野鸭出现异常死亡。采集死亡野鸭的组织提取核酸,经禽流感病毒(AIV)M基因引物初步鉴定定样品中含有AIV,随后H5/H7/H9分型引物鉴定。进一步二代测序后获得了AIV的8片段基因序列。序列比对分析表明,除了NS基因,其余基因与以往报道或H5亚型AIV标准毒株的内部基因同源性较高,HA基因裂解位点具有高致病性(HPAI)AIV的特征,故将感染野鸭的毒株命名为A/Wigeon/Qinghai/2022(H5N1)。从HA基因的遗传进化分析中发现,A/Wigeon/Qinghai/2022(H5N1)与最近几年在野鸟中流行的H5N1和H5N8同在2.3.4.4b分支,而与2005—2015年在青海湖地区流行的毒株遗传距离较远,表明青海湖野鸟源H5亚型AIV遗传多样性丰富,需要持续对该地区野鸟中携带的AIV进行监测。

In August 2022,there was an unusual mortality event among wild ducks in Qinghai Province,Chi-na.The nucleic acid was extracted from the collected tissues of the dead wild ducks,and the M gene of avian influ-enza virus(AIV)was first detected by universal RT-PCR and then the H5/H7/H9 specific genes were detected by using subtyping primers.The wild duck tissues were found to contain the nucleic acid of H5 subtype AIV.The complete genome of detected AIV was further sequenced by next generation sequence,and the 8 segments of the AIV were obtained.Analysis using Basic Local Alignment Search Tool revealed that,except for the NS gene,the other segments showed the highest homology with those of the H5N1 subtype.The HA gene cleavage site exhibited the characters of highly pathogenic avian influenza(HPAI)virus.The strain detected from the wild ducks was named A/Wigeon/Qinghai/2022(H5N1).Genetic evolution analysis of the HA gene indicated that A/Wigeon/Qinghai/2022(H5N1)belonged to the 2.3.4.4b subclade including H5N1 and H5N8,which has been circulating in wild birds in recent years,while showing a distant genetic relationship with the strains that were prevalent in Qinghai Province from 2005 to 2015.This study indicates that the genetic diversity of H5 subtype AIV derived from wild birds in Qinghai Lake is abundant,emphasizing the need for continuous monitoring of AIV carried by wild birds in the area.