一株H4亚型禽流感病毒全基因组序列测定及遗传演化分析

摘要

2008年对我国南方活禽市场进行流行病学监测时从鸭体内分离鉴定一株H4亚型禽流感病毒(AIV),命名为A/duck/Guangxi/912/2008(H4N2)(缩写为DK/GX/912/08).为了解该株H4亚型AIV的来源、特征及其分子演化规律,本研究对其全基因序列进行测定,并与GenBank登录的相关病毒进行遗传演化分析.结果表明:DK/GX/912/08 HA基因切割住点附近的氨基酸序列(PEKASR ↓ GLF)符合低致病力AIV的特征,其分子遗传演化关系属于东半球谱系的欧亚分支;NA基因与A/duck/Jiangxi/1286/2005(H5N2)在同一分支内,核苷酸同源性为98.1%;PB2基因与A/duck/Nanchang/4-165/2000(H4N6)处于同一分支;而NS基因与A/duck/Jiangxi/1786/03(H7N7)同源性最高.因此,推测DK/GX/912/08可能是不同来源的基因在鸭体内经过复杂重组演变的一株重组病毒.%H4N2 subtype avian influenza virus (AIV) [A/duck/Guangxi/912/2008 (H4N2)]was isolated from duck in a live-bird market (LBM) in southern China during the routine epidemiologic surveillance in 2008.The sequence analysis of the hemagglutinin (HA) gene showed that the virus was categorized as low pathogenic AIV, with the typical HA cleavage site of PEKASR ↓ GLF.The phylogenic analysis indicated that the HA gene of the isolate was derived from the Eurasian lineage.The NA gene was closely related to that of A/duck/Jiangxi/1286/2005 (H5N2), sharing 98.1％ sequence identity.The PB2 gene fell into the same cluster with A/duck/Nanchang/4-165/2000 (H4N6).The NS segment was at the same cluster with A/duck/Jiangxi/1786/03 (H7N7).These data indicated A/duck/Guangxi/912/2008 could be reasserted from different subtypes of AIV.This study also highlights the importance of continued surveillance of AIV in LBM.