肠道病毒71型流行病学特征与VP1区基因型研究

Epidemiological characteristics of enterovirus 71 and genotyping of VP1 region

目的：研究2012年5月－2013年4月肠道病毒71型（EV71）流行病学特征及 V P1区基因型特征，为该地区手足口病的防治提供科学参考。方法用实时荧光 PCR（FQ-PCR）方法对手足口病患儿咽拭子标本进行检测，对 EV71阳性样本通过 RT-PCR 方法扩增 V P1区全长基因，将扩增产物进行序列测定，利用生物信息学软件对序列进行分析，构建遗传进化树。结果196例 EV71感染患儿男124例，女72例，男女比例为1．72∶1，年龄以3岁以下为主，占93．9％；3～6月份为高发月份；6株来源于不同疾病程度的样本测序成功，6株 EV71 V P1基因间的核苷酸相似性为96．0％～99．7％，氨基酸相似性为94．6％～100．0％，来源不同疾病程度的 EV71 V P1基因未发现特异性核苷酸变异；在系统进化树上，均与 C4a 亚型代表株处于同一分支，核苷酸相似性为96．0％～98．6％，氨基酸相似性为98．0％～99．6％。结论手足口病患儿感染 EV71 以3岁以下的婴幼儿为主，在3～6月份多发，男性感染高于女性；EV71流行株属肠道病毒71型 C 基因型的 C4亚型，V P1基因与疾病的严重程度无明显关联。

OBJECTIVE To study the epidemiological characteristics of enterovirus 71 （EV71） and the genotyping of V P1 region from May 2012 to Apr 2013 so as to provide scientific basis for prevention and treatment of hand , foot ,and mouth disease in this area .METHODS The throat swab specimens that were obtained from children with hand ,foot ,and mouth disease were detected by using real-time fluorescence quantitative PCR （FQ-PCR） ,then the V P1 gene of EV71 tested positive in the specimens was amplified by reverse-transcription polymerase-chain-reac-tion （RT-PCR） ,the PCR products were sequenced ,and the bioinformatics software was used to analyze the se-quences and construct the phylogenetic tree .RESULTS Totally 196 children were infected with EV71 ,including 124 males and 72 females ,with the male to female ratio of 1 .72 ：1 ;the children aged less than 3 years old accoun-ted for 93 .9% .The incidence of EV71 infection was high during the period of Mar to Jun .Six strains that were i-solated from the specimens obtained from the children with different severities of diseases were sequenced success -fully .The nucleotide sequences of the EV71 V P1 gene among the six strains shared 96 .0% to 99 .7% in homology and 94 .6% to 100 .0% in the deduced amino acid sequences .There was no specific mutation in the nucleotide se-quences of V P1 genes in the strains isolated from the children with different severities of diseases .They clustered with reference strains of subgenotype C4a in the phylogenetic tree .The nucleotide sequences of the EV71 V P1 gene shared 96 .0% to 98 .6% in homology and 98 .0% to 99 .6% in the deduced amino acid sequences .CONCLUSION The infants aged less than 3 years old are the major population with EV71 infection ,which is the most prevalent in the period from Mar to Jun ,and the incidence of the infection is higher in the male than in the female .The EV71 epidemic strain belongs to the subtype C4 of EV71 genotype C ,and the V P1 gene is not significantly associated with the severity of the disease .