2018年昆明市手足口病病原谱及柯萨奇病毒A组6型病毒基因特征分析

Etiology of hand, foot and mouth disease and the genetic characteristics of CV-A6 in Kunming city of China during 2018

目的了解2018年云南省昆明市手足口病病原谱,并对柯萨奇病毒A组6型(coxsackievirus A6, CV-A6)完整VP1区基因特征进行分析。方法收集2018年云南省昆明市手足口病实验室监测系统采集的儿童病例粪便标本757份,对标本中肠道病毒(enterovirus, EV)VP1区基因进行逆转录-聚合酶链式反应和测序。用MEGA 5.2软件构建CV-A6系统进化树,进行基因特征和分子流行病学分析。结果 2018年云南省昆明市手足口病病例中的EV核酸检测阳性率为11.62%(88/757),其中CV-A4、CV-A6、CV-A10、CV-A16和EV-A71的阳性率依次为0.66%(5/757)、4.89%(37/757)、2.51%(19/757)、0.92%(7/757)和2.38%(18/757),CV-A9和E11的阳性率均为0.13%(1/757)。CV-A6基因进化分析表明,37株CV-A6均为D3亚型,与国内报道的结果一致。结论 2018年昆明市发生了以CV-A6为主的手足口病暴发,同时存在CV-A10、CV-A16和EV-A71的共同流行。CV-A6毒株在昆明市存在4个传播链,多种病毒的共同流行和多种传播链的存在给昆明市手足口病的防控带来了严峻的考验。

Objective To analyze the epidemiological features of enteroviruses and the genetic characteristics of coxsackievirus A6(CV-A6) isolated from hand, foot and mouth disease(HFMD) in Kunming city in 2018. Methods The enterovirus(EV) VP1 gene was amplified and sequenced according to published references.The entire VP1 gene sequence of CV-A6 was downloaded from the GenBank.Phylogenetic trees were constructed and the genetic characteristics were analyzed by MEGA 5.2 software. Results The EV RNA detection rate of HFMD patients in Kunming city in 2018 was 11.62%(88/757).The positive rate of CV-A4 was 0.66%(5/757), CV-A6 4.89%(37/757), CV-A10 2.51%(19/757), CV-A16 0.92%(7/757), EV-A71 2.38%(18/757).CV-A9 and E11 coinfection was 0.13%(1/757).The phylogenetic analysis showed that all 37 strains of CV-A6 belonged to sub-genotype D3, similar to previous reports in China. Conclusions There was a large HFMD outbreak caused by CV-A6, co-circulated with CV-A10, EV-A71 and CV-A16 in Kunming city in 2018.The genetic characteristics analysis of CV-A6 shows that this outbreak is caused by four transmission chains.