我国长三角地区首例人感染H5N6禽流感病毒的分离、鉴定与进化特征

Isolation,identification and evolutionary characteristics of the first human infection with H5N6 avian influenza virus in the Yangtze river delta region of China

目的对我国长三角地区首例人感染H5N6禽流感进行病毒分离、鉴定和进化分析。方法通过荧光定量RTPCR法进行流感病毒分型检测,阳性标本用SPF鸡胚进行病毒分离,对病毒分离物进行全基因组扩增测序,利用Blastn、ClustalX和Mega 6.1等软件进行序列比对和系统进化分析。结果2019年11月禽流感患者标本中分离到1株H5N6禽流感病毒毒株,该病毒属于clade 2.3.4.4h,其HA蛋白裂解位点含有多个碱性氨基酸,为高致病性禽流感病毒。病毒HA蛋白的Q222和G224位氨基酸未发生突变,保留了禽类受体α2-3半乳糖苷唾液酸结合特性;AA158位点丧失糖基化,但AA124出现1个新的潜在糖基化位点。结论长三角地区首例人感染的H5N6禽流感病毒是1株新基因重配的高致病性禽流感病毒,与近年来家禽中流行的病毒高度同源,提示应该加强对禽流感病毒的监测和跨种传播的研究。

Objective To isolate,identify and analyze the evolutionary characteristics of the first human infection with H5 N6 avian influenza virus in the Yangtze river delta region of China.Methods Specimens were detected by real-time quantitative PCR method,the positive samples were subjected to typing analysis and viral isolation by culture in SPF chicken embryos.Whole genome sequence analysis was conducted,pairwise sequence alignments and phylogenetic analysis were performed by Blasts,ClustalX and Mega 6.1 softwares.Results A H5 N6 avian influenza virus strain was isolated from a patient infected with H5 N6 avian influenza virus in Nov 2019.The isolated virus belonged to clade 2.3.4.4 h,and its HA protein cleavage site contained multiple basic amino acids,indicating it was a highly pathogenic avian influenza virus.The Q222 and G224 amino acids of HA proteins of isolated viruses did not mutate,retaining the binding characteristics of avian receptorα2-3 galactoside sialic acid(SAα2-3 Gal);amino acid 158 site lost glycosylation site,while amino acid 124 site emerged a new potential glycosylation site.Conclusion The virus causing first human infection with H5 N6 avian influenza virus in the Yangtze river delta region is a highly pathogenic avian influenza virus resulting from gene rearrangement,which is highly homologous with virus strains prevalent in poultry in recent years.The surveillance of avian influenza virus and the study of cross species transmission should be strengthened.