2016-2017年宁夏手足口病的病原构成及流行的EV-A71和CV-A16基因特征分析

摘要

目的 了解引起2016-2017年宁夏自治区(宁夏)手足口病(hand,foot and mouth disease,HFMD)的病原构成,分析主要病原体肠道病毒A组71型(Enterovirus A71,EV-A71)和柯萨奇病毒A组16型(coxsackievirus A 16,CV-A16)的基因特征.方法 分析2016-2017年宁夏HFMD 的核酸检测结果,确定HFMD的病原构成;对2016-2017年宁夏上送至国家HFMD网络监测实验室的肠道病毒毒株利用RT-PCR方法扩增VP1编码区并进行基因序列测定,BLAST分析确定毒株的血清型别,同时选取EV-A71和CV-A16分离株分别构建系统进化树.结果 核酸检测结果 显示,2016和2017年宁夏HFMD中阳性检出率最高的病原体分别为其他肠道病毒(enterovirus,EV)(397,43.72％)和EV-A71(918,56.18％),且不同月份检测出的优势病原体有差异.2017和2016年相比HFMD的病原构成由其他EV和CV-A16为主转变成EV-A71和其他EV为主.2016-2017年宁夏上送至国家HFMD网络监测实验室的EV-A71均属于C4基因亚型的C4a进化分支,CV-A16均属于B1基因亚型的B1b进化分支.结论 宁夏HFMD的病原构成中,2017年EV-A71、CV-A16和其他EV的构成与2016年相比发生了动态变化,持续开展宁夏HFMD的病原构成中EV-A71的动态变化,对指导EV-A71疫苗的使用策略、集中优势医疗资源加强救治重症病例,降低重症HFMD的病死率具有重要意义.%Objective To understand the pathogenic composition of hand,foot and mouth disease (HFMD) in Ningxia Hui Autonomous Region (Ningxia) from 2016 to 2017,and analyze the genetic characteristics of the main pathogens enterovirus (EV)-A71 and coxsackievirus (CV)-A16.Methods Analysis of the result of nucleic acid testing of HFMD in Ningxia from 2016 to 2017 to determine the pathogenic composition of HFMD.The complete VP1 coding region was amplified by RT-PCR and the gene sequence was determined for the enterovirus strains sent to the National HFMD Network Monitoring Laboratory in Ningxia from 2016 to 2017.BLAST analysis confirmed the serotype of the strain,and the phylogenetic tree was constructed respectively by selecting EV-A71 and CV-A16 isolates.Results The leading pathogens of HFMD in Ningxia of 2016 and 2017 were other EV (397,43.72％) and EV-A71 (918,56.18％) respectively,and the dominant pathogens in different months may differ.The pathogenic composition causing HFMD in the past two years has changed from CV-A16 and other EV to EV-A71 and other EV.The isolated EV-A71 strains were C4a evolutionary branch and the isolated CV-A16 strains were B1b evolutionary branch.Conclusions Compared to 2016,in 2017 EV-A71,CV-A16 and other EV changed dynamically.Dynamic monitoring of EV-A71 in Ningxia is of great significance to guide the strategy of using EV-A71 vaccine,concentrating medical resources to strengthen the treatment and reduce the mortality rate of severe HFMD cases.