2013-2021年在沈阳地区持续传播的柯萨奇病毒A组6型的分子进化研究

Molecular Evolutionary Study of Coxsackie Virus Group A Type 6 with the Sustained Transmission in Shenyang,China from 2013 to 2021

手足口病(Hand foot and mouth disease,HFMD)是一种儿童常见的传染性疾病。持续的研究表明,柯萨奇病毒A组6型(Coxsackievirus A6,CVA6)已经成为其主要病原。本研究为分析辽宁省沈阳地区CVA6的VP1区病原学特点及其分子进化特征,收集了2013-2021年沈阳地区手足口病患者标本,应用荧光定量PCR方法进行CVA6等肠道病毒核酸的检测,对CVA6核酸阳性标本应用RT-PCR方法针对VP1区全长进行扩增、核苷酸序列测定,使用MEGA软件进行遗传进化和氨基酸突变位点分析。结果表明2013-2021年间沈阳地区CVA6占肠道病毒阳性构成比的36.08%(1269/3517),2015年和2018年成为绝对优势流行株,分别为68.38%(240/351)和58.30%(316/542)。进化分析表明,2013-2021年间沈阳地区的CVA6均属于D3a基因型,其中2013-2014年CVA6位于D3a.1和D3a.2分支上,而2015-2021年毒株均位于D3a.2分支上。与参考株相比,沈阳地区CVA6的VP1蛋白上存在24个氨基酸突变位点。因此,CVA6为近年来沈阳地区手足口病的主要病原体之一,基于VP1区进化分析,可看出2013-2021年间沈阳地区CVA6均属于D3a基因型,且已由D3a.1分支进化到D3a.2分支,并持续流行至今。加强CVA6的持续性监测与病原特征分析,对HFMD的科学防控具有重要意义。

Hand foot and mouth disease(HFMD)is a common infectious disease in children.Continuing studies have shown that Coxsackievirus group A type 6(CVA6)has become its major pathogen.This study was conducted to analyze the pathogenic characteristics of VP1 region of CVA6 and its molecular evolutionary features in Shenyang,Liaoning Province,China.Samples from patients with HFMD in Shenyang,China from 2013 to 2021 were collected.Fluorescent quantitative PCR was adopted to detect enterovirus nucleic acids such as CVA6.Conventional RT-PCR was used to amplify and sequence the full length of the VP1 region in CVA6nucleic acid positive samples.MEGA software was used to analyze genetic evolution and amino acid mutation sites.The results showed that CVA6 accounted for 36.08%(1,269/3,517)of the positive proportion of enteroviruses in Shenyang,China during 2013-2021.In 2015 and2018,CVA6 became an absolute dominant epidemic strain,accounting for 68.38%(240/351)and 58.30%(316/542),respectively.Evolutionary analysis showed that CVA6 in Shenyang region,China during 2013-2021 belonged to the D3a genotype,with CVA6located on the D3a.1 and D3a.2 branches from 2013-2014,while the virus strains were located on the D3a.2branch from 2015-2021.Compared with the reference strain,there are 24 amino acid mutation sites on the VP1protein of CVA6 in Shenyang area,China.CVA6 is one of the main pathogens of HFMD in Shenyang,China in recent years.Based on the evolution analysis of VP1 region,it can be seen that CVA6 in Shenyang region,China belonged to the D3a genotype between 2013 and 2021,which has evolved from the D3a.1 branch to the D3a.2 branch,and has been circulating until now.Therefore,it is important to strengthen the continuous monitoring and pathogenic characterization of CVA6 for the scientific prevention and control of HFMD.