云南省2016年输入性B5基因亚型EV-A71的鉴定和基因特征分析

Genetic Analysis and Identification of Imported EV-A71 in Yunnan Province,China in 2016

手足口病是一种发病率较高,易发生传播的传染病,居我国丙类报告传染病发病数首位。本研究对云南省2016年手足口病患儿的临床标本随机抽取1%进行病毒分离和核酸检测,分子分型结果显示134株为EV-A71,占比36.91%,包含C4（130株）和B5（4株）两个基因亚型。其中所有C4基因亚型EV-A71序列均属于C4a进化分支,为中国大陆目前流行的优势基因型,而4株B5基因亚型EV-A71是云南省首次报道,属于输入基因型。从进化关系上4株云南输入性B5基因亚型EV-A71与越南流行株同源关系较近,并且其中3株在进化树上簇集,不排除省内局限性传播的可能性。因此,非本土流行的输入基因型EV-A71可能已成为一个影响我国手足口病预防控制的重要挑战。

Hand,foot and mouth disease（HFMD）is a highly contagious disease,and the number of HFMD patients ranks top one among type＂C＂infectious diseases in China.In this study,samples from HFMD patients were collected and the enterovirus nucleic acid detections were performed.About 1% of positive samples were selected randomly for viral isolation.The result of molecular typing showed that 134 strains were EV-A71（36.91%）.All the EV-A71 strains were further classified into C4 genotype（130 strains）and B5 genotype（4 strains）based on phylogenetic analysis.Among them,all 130 C4 strains belonged to C4 aevolutionary branch,which is the predominant subgenotype in China's Mainland.The four strains of B5 genotype EV-A71 belonged to an imported genotype,which is the first report in Yunnan Province of China.Based on the tree topological relationship,the imported B5 genotype EV-A71 strains were more homologous with strains circulated in Vietnam in the same period.The possibility of low-level local spread couldn’t be excluded.It is therefore possible that imported genotype of EV-A71 has become an important challenge on HFMD control and prevention.