2017年淮南市外环境H7N9病毒HA和NA基因特征分析  

Characteristics of HA and NA genes of H7N9 avian influenza virus in the environment in 2017 from Huainan city of China

作　　者：刘江[1] 何军[2] 曾凡荣[1] 余寿杰[1] 何玢[1] 杨光[1] 李杰[1] LIU Jiang;HE Jun;ZENG Fan-rong;YU Shou-jie;HE Bin;YANG Guang;LI Jie(Center for Disease Control and Prevention of bluainan City, Huainan, Anhui 232033, Chin)

机构地区：[1]淮南市疾病预防控制中心,安徽淮南232033 [2]安徽省疾病预防控制中心,安徽合肥230601

出　　处：《中国病毒病杂志》2018年第1期50-57,共8页Chinese Journal of Viral Diseases

摘　　要：目的分析淮南市2017年外环境标本中H7N9禽流感病毒血凝素基因(hemagglutinin,HA)及神经氨酸酶基因(neuraminidase,NA)的基因特征。方法采集活禽市场禽类咽拭子、肛拭子、粪便、笼具、台面或砧板、脱毛机、禽类饮水、污水等标本,进行禽流感病毒Real-time PCR分型检测,选取H7N9核酸阳性标本(CT值≤28),对其HA和NA基因进行特异性扩增,并对扩增产物进行基因序列测定。采用Bioedit5.0.9、DNASTAR7.1软件对测序结果拼接,并选取国内外H7N9参考序列使用Mega 6.06软件构建HA和NA基因遗传进化树。结果淮南市外环境3株H7N9禽流感毒株HA基因其核苷酸同源性为98.7%~100.0%,氨基酸序列同源性为99.3%~100.0%,基因进化分析显示,该3株H7N9禽流感毒株与安徽、江苏、浙江分离毒株亲缘性较近,处于长三角分支内,与2017年安徽株A/Anhui/13449/2017/H7N9(EPI258029)核苷酸同源性为98.7%~99.9%,氨基酸同源性为99.3%~100.0%,HA发生G186V、Q226L突变;NA基因核苷酸同源性为98.3%~100.0%,氨基酸同源性为99.5%~100.0%;基因进化分析显示,淮南株HN-3、HN-4与2017年安徽分离株A/Anhui/13449/2017/H7N9(EPI 258029)亲缘性最近,核苷酸同源性为98.7%~99.7%,氨基酸同源性为99.5%~100.0%,NA蛋白R294K耐药位点无变异,NA茎区69~73位缺失了"QISNT"序列。结论淮南市活禽市场外环境H7N9病毒HA基因和NA基因与人感染H7N9安徽株(EPI 258029)A/Anhui/13449/2017/H7N9高度同源,处于同一进化分支,有共同的进化来源;HA受体结合位点氨基酸发生G186V、Q226L变异,NA茎区69~73位缺失"QISNT"序列均加强了病毒感染人类的能力。Objective To analyze the characteristics of hemagglutinin（HA）gene and neuraminidase（NA）gene of H7 N9 avian influenza virus isolated from the environment in 2017 in Huainan city of China. Methods Samples of throat swab,anal swab,feces,cage,table top or cutting board,hair removal machine,poultry drinking water and sewage were collected from live poultry markets in Huainan city of China in 2017.H7 N9 avian influenza virus was detected by real-time PCR for genotyping.For specimens with PCR CT values below28,HA and NA gene specific primers were used to amplify the two genes and the PCR products were sequenced.Bioedit5.0.9 and DNASTAR7.1 software was used to splice the sequences and Mega 6.06 was used to analyze the phylogenetic relationship between HA and NA genes. Results The HA genes of 3 strains of H7 N9 avian influenza virus isolated from Huainan city share 98.7%-100.0% nucleotide homology and 99.3%-100.0% amino acid homology.Genetic evolution analysis showed that reported isolates from Anhui,Jiangsu and Zhejiang were closed to 3 strains isolated in this study,and all locate in the Yangtze River Delta clade.HA epitope displayed G186 Vto Q226 Lat the receptor binding site.NA genes showed 98.3%-100.0%nucleotide and 99.5%-100.0% amino acid homology.Comparing to the reported 2017 Anhui isolate（EPI258029）,the nucleotide homology of HN3 and HN4 was 98.7%-99.7% and amino acid homology was99.5%-100.0% while no changes were found at the NA R294 Kresistance site,the ＂QISNT＂at sites 69-73 were missing in the stem region. Conclusions The HA gene and NA gene of H7 N9 influenza virus isolated from live poultry markets in Huainan city of China are highly homologous with reported human H7 N9 Anhui strain（EPI 258029）,and are in the same evolutionary branch and share a common evolutionary source.HA showed G186 V,Q226 Lat receptor binding site.Deletion of＂QISNT＂ in the stem region at sites 69-73 may enhance the ability of the virus to infect humans.

关 键 词：H7N9 禽流感 Real-time PCR 外环境 血凝素基因(HA) 神经氨酸酶基因(NA) 毒株亲缘性 核苷酸同源性 氨基酸同源性 

分 类 号：R183.3[医药卫生—流行病学]