广东省柯萨奇病毒A8型流行及其VP1基因特征分析

Epidemic and VP1 genetic characteristics of coxsackievirus A8 in Guangdong province,2010-2020

目的了解广东省柯萨奇病毒A8型(CVA8)的流行特点及其基因特征。方法收集2010—2020年广东省手足口病非EV71/CVA16/CVA6其他肠道病毒(其他EV)阳性样本,分型鉴定,选取CVA8阳性样本进行病毒分离,对获得的CVA8毒株进行VP1全长序列扩增与测序,运用生物信息学软件进行遗传进化分析。结果2010—2020年手足口病2650份其他EV样本中,CVA8占2.6%(69/2650),每年的构成比在0.5%~12.0%,其中2020年最高;广东省共有13个地市检出CVA8,其中2020年7—11月汕头市检出最多(28例);对CVA8阳性样本进行病毒分离,阳性分离率为73.9%(51/69);遗传进化分析显示,CVA8可分为A、B、C、D和E等5个基因型,本研究44株CVA8毒株VP1核苷酸同源性为77.8%~100.0%,氨基酸序列同源性为92.9%~100.0%,包括D基因型(5株)和E基因型(39株);2020年7—11月汕头市28株CVA8流行株的核苷酸同源性为99.3%~100.0%,高度同源。结论CVA8在广东省以散发流行为主,2020年7—11月在汕头市引起了手足口病的局部持续循环流行;广东省存在CVA8病毒D和E基因型的流行,其中E基因型是目前的流行株。

Objective To study the epidemic and genetic characteristics of coxsackievirus A8(CVA8)in Guangdong province.Methods From all specimens sampled in hand,foot,and mouth disease(HFMD)cases reported during 2010-2020 in Guangdong province,we collected those of other enterovirus(EV)-non-EV71/CVA16/CVA6.After amplified VP1 gene based-genotype identification,CVA8 strains were isolated from the specimens using rhabdomyosarcoma(RDa)cells.The entire VP1 region of the isolated CVA8 strains were amplified and sequenced and then phylogenetically analyzed using DNASTAR6.0 and MEGA6.06 software packages.Results Of totally 2650 other EV specimens collected during the period,2.6%(69)were positive for CVA8 and the annual ratio of CVA8 positive specimens ranged from 0.5%to 12.0%,with the highest ratio in 2020.The CVA8 positive specimens were detected in 13 cities of the province and the highest clustering of positive specimens(28)was detected in Shantou city during July-November 2020.CVA8 strains were isolated from 73.9%(51)of the positive specimens.The phylogenetic analysis results indicated that CVA8 could be divided into five genotypes:A,B,C,D and E.The 44 CVA8 strains isolated in this study shared 77.8%-100.0%homologies in nucleotide and 92.9%-100.0%in amino acid,including genotype D(5 strains)and genotype E(39 strains),and the nucleotide homology of 28 CVA8 strains isolated in Shantou city during July-November 2020 was 99.3%-100.0%.Conclusion CVA8 was prevalent sporadically in Guangdong province during 2010-2020 generally but highly prevalence among local HFMD cases in Shantou city during July-November 2020.CVA8 strains of genotype D and E were prevalent and strains of genotype E are currently prevalent in Guangdong province.