2017年安徽省宿州市人感染H7N9禽流感病毒基因组特征分析

Genomic analysis of avian influenza A（H7N9） virus in Suzhou, Anhui, 2017

目的分析2017年安徽省宿州市人感染H7N9禽流感病毒的基因组分子进化特征。方法收集宿州市4例H7N9病例的咽拭子样本，分离培养后进行扩增和测序，构建血凝素HA基因进化树并进行重要氨基酸位点的变异分析。结果4株毒株的HA与A／Henan／15337／2017（H7N9）的相似度最高（99％）；神经氨酸酶NA与A/changsha，44／2017（H7N9）的相似度最高（99％-100％）；其他内部基因与2013-2017年浙江省、湖南省、江西省和广东省等地区分离到的H9N2相似度较高（94％-100％）。分子进化树显示均为长三角分支。HA蛋白受体结合位点未发生G186V、Q226L突变；NA蛋白上未发现耐神经氨酸酶的位点突变；PB2蛋白发生E627V突变；M1蛋白出现N30D、T215A突变；NS1蛋白出现P42S突变、盘状同源区域模块缺失；M2蛋白出现S31N突变。结论4株人感染H7N9禽流感病毒均处于长三角分支，M2蛋白s31N突变提示对M2离子通道抑制剂出现耐药，应及时关注其遗传变异演变方向，为H7N9禽流感的有效防治提供科学依据。

Objective To illustrate molecular evolution and biological characteristics of avian influenza A （HTN9） virus isolated in Suzhou, Anhui in 2017. Methods The 4 strains of influenza A （HTNg） were isolated from throat swab samples and the viral genomes were sequenced. Phylogentic tree wasconstructed and mutations at important amino acid sites were analyzed. Results The HA genes of the four strains had the highest similarity （99%） with A/Henan/15337/2017 （H7N9） and NA genes had a similarity of 99%-100% with A/Changsha/44/2017 （H7N9）. The internal genes showed high similarity （94%-100%） to avian influenza A （H9N2） virus strains from Zhejiang, Hunan, Jiangxi and Guangdong provinces between 2013 to 2017. Phylogenetic analysis indicated that HA genes of the four strains belonged to the Yangtze River Delta branch. Neither G186V and Q226L mutations in HA receptor site nor the mutations related to resistance of neuraminidase inhibitant in NA protein was found. The mutations, including E627V mutation in PB2 protein, N30D and T215A mutations in M1 protein, P42S and PDZ motif deletion in NS1 protein, and $31N mutation in M2 protein were found. Conclusions The 4 strains of human avian influenza A （H7N9） virus were all in the Yangtze River Delta branch. Resistance to M2 ion channel inhibitant occurred. Therefore, more attention should be paid on the genetic evolution of the virus for the effective prevention and treatment of H7N9 avian influenza in Suzhou, Anhui province.