海南省2016-2018年A(H1N1)pdm09亚型流感病毒基因特性分析

2009年A(H1N1)pdm09亚型流感病毒在墨西哥暴发,之后在全世界流行。为了解海南省2016-2018年A(H1N1)pdm09亚型流感病毒流行态势,分析血凝素(HA)与神经氨酸酶(NA)基因遗传进化特征与变异情况,本研究从中国流感监测信息系统获取海南省2016-2018年流感病毒病原学监测数据,选取5家流感监测网络实验室分离鉴定的37株A(H1N1)pdm09亚型流感毒株进行HA与NA基因测序,利用MEGA 10.1.8构建HA与NA基因种系进化树,并分析其氨基酸变异情况。结果显示,2016-2018年共出现3次A(H1N1)pdm09亚型流感病毒活动高峰。2017年10月份以后的分离株(4/8)与2018年大部分分离株(21/22)独立于疫苗株A/Michigan/45/2015聚为一个小支,发生20余处HA与NA氨基酸位点变异。与疫苗株A/California/7/2009(2010-2016)相比,2016-2018年流感病毒分离株在HA基因抗原决定簇上发生7处氨基酸变异并有一个潜在糖基化位点,未发现HA基因受体结合位点变异与NA基因耐药性变异。本研究提示,2016-2018年,A(H1N1)pdm09亚型流感病毒逐步发生规律性进化,氨基酸变异频率有增加趋势,今后应持续加强流感病毒病原学监测,密切追踪A(H1N1)pdm09亚型流感病毒基因变异情况,为科学防控提供理论依据。

Genetic Characteristics of Influenza A(H1N1)pdm09 Virus Strains in Hainan Province,China,During 2016-2018

The influenza A(H1 N1)pdm09 virus outbreak in Mexico in 2009 and prevalents worldwide.To investigate the epidemic situation and genetic characteristics of influenza A(H1 N1)pdm09 virus strains in Hainan Province,China,during 2016–2018,surveillance results for influenza viruses in Hainan Province,China,during 2016–2018 were collected from the China Influenza Surveillance Information System.Thirtyseven influenza A(H1 N1)pdm09 virus strains were selected from five laboratories in the influenza-surveillance network to undertake sequencing of HA and NA genes.A phylogenetic tree was constructed by MEGA 10.1.8,and amino-acid substitutions were analyzed.Results showed that three epidemic peaks during 2016–2018 were documented.Four out of eight strains after October 2017 and 21 out of 22 strains in 2018 were different from the vaccine strain A/Michigan/45/2015 and grouped into one branch,showing>20 HA and NA amino-acid substitutions.Compared with the vaccine strain A/California/7/2009(2010–2016),seven amino-acid substitutions in the HA antigen epitope occurred in 2016–2018 isolates with a glycosylation site.Substitutions in receptor-binding sites in the HA gene and drug-resistant variants in the NA gene were not observed.The present study suggested that influenza A(H1 N1)pdm09 virus strains underwent phylogenetic variations regularly,with an increased frequency of amino-acid mutations during 2016–2018.We should further strengthen the surveillance of influenza viruses and continue tracing virus variations to provide scientific evidence for prevention of infection by influenza viruses.