2019年EV-A71疫苗接种地区手足口病肠道病毒分子流行病学分析

Molecular epidemiological analysis of enteroviruses associated with hand,foot and mouth disease in areas vaccinated with EV-A71 in 2019

目的分析2019年EV-A71疫苗在湖北省潜江市和谷城县两地区接种后,手足口病(hand,foot and mouth disease,HFMD)相关肠道病毒病原谱结构及分子流行病学特征。方法采集谷城县2019年6—12月和潜江市2019年5—12月HFMD患儿肛拭子标本,通过多通道real-time RT-PCR技术对肠道病毒阳性样本进行初步分型筛选后,采用常规RT-PCR方法对肠道病毒VP1区部分基因扩增测序,通过DNAStar 7.0、MEGA 6.0等软件进行分子进化特征分析。结果共收集谷城县2019年6—12月和潜江市2019年5—12月HFMD样本520份,检出肠道病毒阳性样本490份,阳性率94.23%。其中谷城县检出肠道病毒阳性样本242份,共检出6种肠道病毒,各病原及构成比分别为CV-A684.30%、CV-A162.48%、CV-A107.44%、CV-A53.31%、CV-A40.83%、CV-A80.41%、其他未定型的肠道病毒(other enterovirus,other EV)1.24%;潜江市检出肠道病毒阳性样本248份,共检出4种肠道病毒,各病原及构成比分别为CV-A654.80%、CV-A1640.4%、CV-A54.40%、CV-A80.40%。对几种主要流行的病原基于VP1分子进化树分析结果表明,谷城县和潜江市两地区的CV-A6均属于D3亚型,谷城县CV-A10属于C亚型,潜江市CV-A16属于B1b亚型,谷城县CV-A16属于B1a亚型。结论2019年下半年,谷城县和潜江市两地区在EV-A71疫苗的干预下,HFMD病原谱为多种基因型的肠道病毒共同流行,其中CV-A6为优势病原体,未发现由EV-A71病原引起的HFMD,表明EV-A71疫苗的接种在接种地区形成了良好的保护效果。

Objective To analyze the pathogenic spectrum and molecular epidemiological characteristics of enteroviruses associated with hand,foot and mouth disease(HFMD)after vaccination with EV-A71 vaccine in Qianjiang City and Gucheng County,Hubei Province,China in 2019.Methods The anal swabs of children with HFMD in Gucheng County from June to December 2019 and in Qianjiang City from May to December 2019 were collected.After the positive samples of enteroviruses were typed and screened by multi-channel real-time RT-PCR,partial genes in the VP1 region were amplified and sequenced by conventional RT-PCR.The molecular evolution characteristics were analyzed by using DNAStar 7.0 and MEGA 6.0 software.Results A total of 520 samples were collected from children with HFMD,of which 490 were positive for enterovirus,indicating a positive rate of 94.23%.A total of 242 enterovirus positive samples were detected in Gucheng County,including six serotypes,in which the constituent ratios of CV-A6,CV-A16,CV-A10,CV-A5,CV-A4,CV-A8 and other enterovirus were 84.30%,2.48%,7.44%,3.31%,0.83%,0.41% and 1.24% respectively.However,a total of 248 enterovirus positive samples were detected in Qianjiang City,including four serotypes,in which the constituent ratios of CV-A6,CV-A16,CV-A5 and CV-A8 were 54.80%,40.4%,4.40% and 0.40% respectively.The molecular phylogenetic tree analysis based on partial VP1 showed that both the CV-A6 in Qianjiang City and Gucheng County were os subtype D3,while the CV-A10 in Gucheng County was of subtype C,the CV-A16 in Qianjiang City was of subtype B1 b,and the CV-A16 in Gucheng County was of subtype B1 a.Conclusion In the second half of 2019,under the intervention of EV-A71 vaccine,the pathogenic spectrums of HFMD in Gucheng County and Qianjiang City were characterized with co-circulation of enteroviruses of multiple genotypes.CV-A6 was the dominant pathogen,and no HFMD caused by EV-A71 was found,suggesting good protective effect of EV-A71 vaccination.