2019年上海市松江区手足口病A组肠道病毒病原特征分析

Analysis of the etiological characteristics of hand,foot and mouth disease in Songjiang district of Shanghai in 2019

目的了解上海市松江区2019年手足口病(hand,foot and mouth disease,HFMD)病原中A组肠道病毒(enterovirus,EV)VP1基因特征。方法使用实时荧光逆转录-聚合酶链式反应(reverse transcription polymerase chain reaction,RT-PCR)检测HFMD疑似病例的标本,EV阳性标本接种人横纹肌肉瘤细胞(rhabdomyosarcoma cells,RD)培养病毒。分离到的A组EV毒株经VP1区基因测序后使用MEGA X软件进行系统进化分析及核苷酸、氨基酸同源性分析。结果2019年共检测207份HFMD标本,其中188份检出EV,柯萨奇病毒(coxsackievirus,CV)-A6、CV-A16、CV-A10、CV-A4阳性分别为47.34%(89/188)、41.49%(78/188)、3.72%(7/188)、2.66%(5/188),其他EV阳性为4.79%(9/188),未检出EV-A71。HFMD夏季流行高峰(5~7月)多检出B1基因亚型的CV-A16,B1a和B1b进化分支共同流行,秋冬季的次高峰(9~12月)检出D3a进化分支的CV-A6较多。CV-A10和CV-A4散在发病,均为C2基因亚型。与原型株相比,CV-A6、CV-A16、CV-A10、CV-A4 VP1基因核苷酸(氨基酸)序列同源性分别为79.22%~81.78%(95.97%~97.19%)、62.70%~65.54%(90.10%~91.30%)、81.76%~82.65%(91.63%~92.03%)、81.09%~81.79%(97.27%~97.67%)。结论HFMD病原体流行的多样性及复杂性增加了HFMD防控难度。EV监测项目的拓展及分子流行病学的研究有助于防控HFMD。

Objective To investigate the characteristics of enterovirus(EV)VP1 gene from cases with hand,foot and mouth disease(HFMD)in Songjiang district of Shanghai in 2019.Methods Samples from suspected HFMD cases were detected using real-time fluorescence reverse transcription polymerase chain reaction(RT-PCR).Human rhabdomyosarcoma(RD)cells were used for EV culture.VP1 genes of the isolated EV A species were sequenced.The sequences of nucleotide and amino acid of EV A species were used in phylogenetic and homology analysis by MEGA X software.Results Totally 207 HFMD specimens were detected in 2019,of which 188 specimens were screened positive for EV.The positive rates of Coxsackievirus(CV)-A6,CV-A16,CV-A10 and CV-A4 were 47.34%(89/188),41.49%(78/188),3.72%(7/188)and 2.66%(5/188),respectively.Other EV species were 4.79%(9/188)positive and EV-A71 was not detected.During the summer epidemic peak of HFMD(May to July),B1 gene subtype of CV-A16 was detected more frequently,of which B1a and B1b evolutionary branches were prevalent together.The CV-A6 virus of D3a branch dominated in secondary peak of autumn and winter(September to December).CV-A10 and CV-A4 were sporadic and both respective strains belonged to subtypes of C2 gene.Compared with the prototype strains,the nucleotide(amino acid)sequence homologies of CV-A6,CV-A16,CV-A10 and CV-A4 VP1 genes were 79.22%-81.78%(95.97%~-97.19%),62.70%-65.54%(90.10%-91.30%),81.76%-82.65%(91.63%-92.03%)and 81.09%-81.79%(97.27%-97.67%),respectively.Conclusions The diversity and complexity of HFMD pathogen epidemic increase the difficulty of HFMD prevention and control.The expansion of EV surveillance programs and the studies on the molecular epidemiology of EV are helpful for the prevention and control of HFMD.