青岛市2014年手足口病病原谱及柯萨奇病毒A10、A6型VP1区基因特征

摘要

目的 阐明青岛地区2014年手足口病(hand,foot and mouth disease,HFMD)病原谱及柯萨奇病毒A10、A6型青岛毒株的基因特征.方法 用荧光RT-PCR法检测2014年青岛地区HFMD患者咽拭子标本总肠道病毒(EV)、肠道病毒71(enterovirus,EV-A71)型、柯萨奇病毒A16(coxsackievirus,A16,CV-A16)型、柯萨奇病毒A10(coxsackievirus,A 10,CV-A10)型和柯萨奇病毒A6(coxsackievirus,A6,CV-A6)型,半巢式反转录PCR扩增其他型肠道病毒VP1区部分基因序列,结合序列分析鉴定血清型.扩增CV-A10和CV-A6 VP1基因全长序列并测序列测定,以Mega 5.0软件进行遗传进化分析.结果 2014年共检测HFMD标本1 727例,鉴定出肠道病毒11种,主要病原为EV-A71(38.0％,410/1 078)、CV-A16(28.8％,311/1 078)、CV-A10(14.1％,152/1 078)和CV-A6(3.2％,34/1 078).CV-A10占HFMD病原构成在不同年龄段患儿间存在显著性差异,随年龄增高下降(x2=15.19,P=0.001),在住院病例病原构成中所占比例显著高于门诊病例(x2=49.1,P＜0.001),且60.0％CV-A10感染的住院病例出现神经系统受损症状.VP1基因遗传进化分析显示,青岛地区2014年CV-A10毒株均属于C基因型,其中71.7％位于C5分支;CV-A6毒株均属于D基因型,其中83.3％位于D5分支.结论 EV-A71、CV-A16、CV-A10和CV-A6是2014年青岛地区HFMD的主要病原.CV-A10在低龄儿童HFMD病原构成中占比例较高,易引起神经系统损害.C基因型的C5分支毒株是CV-A10主要流行毒株,D基因型的D5分支毒株是2014年青岛CV-A6主要流行毒株.%Objective To investigate the etiology spectrum of hand foot and mouth disease (HFMD) and to analyze the molecular characteristics of Coxsackievirus A10 and A6 in Qingdao in 2014.Methods Throat swabs of HFMD cases were tested for total enteroviruses (EVs),EV-A71,CV-A16,CV-A10 and CV-A6 by multiplex real time RT-PCR.Other EV serotypes were identified through the sequences of partial VP1 gene.The full-length of VP1 gene of CV-A10 and CV-A6 were amplified and sequenced.The sequences were phylogenetically analyzed using MEGA 5.0 software package.Results A total of 1727 HFMD patients were detected in 2014 and 1 lserotypes of enteroviruses were identified.EV-A71 (38.0％,410/1078),CV-A16(28.8％,311/1078),CV-A10 (14.1％,152/1078) and CV-A6 (3.2％,34/1078)were the most dominant pathogen in 2014 in Qingdao.Proportions of CV-A 10 in enterovirus infected children varied dramatically in different ages(x2 =15.19,P=0.001),showing a downtrend with age.Proportion of CV-A10 in inpatients was much higher than that in outpatients(x2=49.1,P ＜0.001),while 60％ of those inpatients showed nervous system damage symptoms,with pathological reflex or disappearance of physiological reflex.Phylogenetic analysis of complete VP1 sequences showed that all CV-A10 strains identified in this study belonged to genotype C,71.7％ of which located in branch C5;all CV-A6 strains belonged to genotype D while 83.3％ of which located in branch D5.Conclusions EV-A71,CV-A16,CV-A10 and CV-A6 were the prevalent pathogens of HFMD in Qingdao in 2014.CV-A10 was more frequently detected in lower age group with HFMD,which can cause damage to nervous system.Strains of branch C5 in genotype C were the dominant strains of CV-A10 circulated in Qingdao in 2014 while strains of branch D5 in genotype D were the major strains of CV-A6.