渭南市2016年手足口病病原学及EV 71型基因特征分析

Etiologic characteristics of hand,foot,and mouth disease and genetic features of EV 71 in Weinan,2016

目的了解2016年渭南市手足口病病原学特征和肠道病毒71型(EV 71)基因特征。方法收集渭南市2016年疑似手足口病病例咽拭子样本,采用实时荧光定量PCR法进行核酸分型检测,同时对2株EV 71型病毒株VP1片段进行核苷酸序列测定以及同源性及系统进化分析。结果共检测手足口病病例咽拭子样本1 019份,检出肠道病毒阳性689份,总阳性率为67.62%;各型别病毒阳性率由高到低依次为其他肠道病毒26.89%、EV 71型24.63%和Cox A16型16.09%,差异有统计学意义(P<0.01)。病毒核酸检出阳性主要集中在5―10月,占总阳性数的91.04%(549/603)。病毒核酸检出阳性病例男女性别比为1.26∶1;年龄集中在5岁以下儿童,占93.90%(647/689);散居儿童占67.94%,托幼儿童占32.06%。重症病例以EV 71阳性率最高(72.22%),普通病例以其他肠道病毒阳性率最高(29.04%),差异有统计学意义(P<0.01)。2株EV 71毒株VP1区序列与C4a基因亚型核苷酸和氨基酸同源性最高,分别为96.6%~96.7%和99.3%;系统进化树分析显示,2株EV 71毒株与福建流行株(KU595899.1)同源性最高。结论 2016年渭南市手足口病主要病原体为其他肠道病毒,EV 71是引起渭南市手足口病重症病例的优势病毒型别,渭南市EV 71型毒株属于C4a基因亚型。

Objective To analyze etiologic characteristics of hand, foot, and mouth disease （HFMD） and genetic features of EV 71 in Weinan City in 2016. Methods Specimens of suspected HFMD cases in Weinan in 2016 were collected for determination of enterovirus types by using real-time quantitative PCR （RT-qPCR）. Meanwhile, nucleotide sequence, homology and phylogenetic analysis of VP1 encoding gene were performed in two strains of EV 71. Results A total of 1 019 throat swabs specimens of HFMD were detected and 689 specimens were found to be positive for EV, with a total positive rate of 67.62%. The positive rates of viruses ranging from high to low were 26.89% for the other human enteroviruses （HEV） , 24.63% for EV 71, and 16.09% for Cox A16 （P 〈 0.0l ）. The nucleic acid positive cases of EV were mainly occurred from May to October, accounting for 91.04% （549/603）of the total positive ca- ses. The male to female sex ratio of the nucleic acid positive cases was 1.26： 1. The nucleic acid positive cases were mainly the children aged under five years （93.90% , 647/689 ） , then scattered children （67.94%） and the children in kindergarten （32.06%）. The positive rate of EV 71 was highest in severe cases （72.22%） and that of other HEV was highest in common cases （29.04% ; P 〈 0. 01 ）. The se- quence of VP1 region of two strains of EV 71 had high homology with C4a gene subtype （96.6% -96. 7% ） and amino acids （99.3%）. Phylogenetic tree analysis showed that the two strains of EV 71 had vezy high homology with the epidemic strain of Fujian （ KU595899. 1 ）. Conclusion The other HEV was major virus causing HFMD in Weinan in 2016. EV 71 was the predominant virus subtype causing severe cases of HFMD in Weinan City and belonged to CAa genotype.