广西鸭源H3N8亚型禽流感病毒的分离鉴定及遗传进化分析

Isolation,Identification and Genetic Evolution Analysis of Avian Influenza Virus H3N8 from Ducks in Guangxi

[目的]了解广西水禽中分离到的H3N8亚型禽流感病毒的分子遗传进化特征。[方法]将从活禽市场采集的水禽棉拭子样品经处理后接种SPF鸡胚,应用血凝试验和血凝抑制试验对收取尿囊液进行血清学鉴定,然后对分离到的禽流感病毒进行全基因序列测定和遗传进化分析。[结果]血清学及HA和NA基因测序结果显示,该分离毒株为H3N8亚型禽流感病毒,命名为A/duck/Guangxi/446D28/2021(H3N8)。全基因遗传进化分析显示,其HA蛋白无连续碱性氨基酸插入,符合典型低致病性禽流感病毒的特征;NA蛋白出现耐药性氨基酸位点突变;该毒株8个基因片段在GenBank中比对分析结果显示,其同源性最高的毒株基本主要来自越南和位于我国候鸟迁徙路线上的宁夏及江西等省(区)。[结论]该分离株可能是不同亚型禽流感病毒通过相互基因交换所形成的基因重组体。

[Objective]To understand the molecular genetic evolution characteristics of H3N8 subtype avian influenza virus isolated from waterfowl in Guangxi.[Method]The cotton swab samples collected from live poultry market were treated and inoculated into SPF chicken embryos.The collected allantoic fluid was serologically identified by hemagglutination test and hemagglutination inhibition test,and then the whole gene sequence and genetic evolution analysis of the isolated avian influenza virus were carried out.[Result]Serological HA and NA gene sequencing results showed that the isolated strain was H3N8 subtype avian influenza virus,named A/duck/Guangxi/446D28/2021(H3N8).Genetic evolution analysis of the whole gene showed that there was no continuous basic amino acid insertion in HA protein,which accorded with the characteristics of typical low pathogenic avian influenza virus.NA protein appeared drug-resistant amino acid site mutation;The results of comparative analysis of eight gene fragments of this strain in GenBank showed that the strains with the highest homology mainly came from Vietnam,Ningxia and Jiangxi provinces,which are located on the migratory route of migratory birds in China.[Conclusion]The isolated strain may be a gene recombinant formed by gene exchange among different subtypes of avian influenza viruses.