中国大陆EV71病毒分离株的分子流行病学研究

目的了解1987-2010年中国大陆肠道病毒71型（EV71）分离株的分子流行病学特点及其种系进化、基因分型和遗传变异性。方法从GenBank/NCBI上获得中国大陆来源的具有完整VP1或近似完整VP1基因的核苷酸序列信息的413株EV71毒株进行分析,采用MEGA5.0软件,构建系统进化树,计算相同或不同基因型及基因亚型毒株的核苷酸与氨基酸的相似性。结果 1987-2010年,中国大陆20个省、市或地区均分离到具有完整VP1序列的毒株,且2008年以来数量陡增;中国大陆流行的主要是C型,只有2008年安徽和2009年湖北发现了A型;各基因型在43、58、142、164、167、184、240、249、292等氨基酸位点发生了特异性变异;从健康人体内分离的HQ129932毒株与其他序列比较,氨基酸无特异性变异。结论 C型株可能具有更强的传染力;氨基酸位点变异对于EV71病毒进化有重要意义;VP1基因与疾病的严重程度无明显关联;应加强C4a亚型疫苗候选疫苗株对其他基因型毒株的交叉保护作用研究。

Molecular epidemiology and evolution of enterovirus 71 strains isolated from mainland China

Objective To understand the molecular epidemiology and evolution of EV71 isolated from 1987 to 2010 in mainland China. Methods The 413 nucleotide sequences of EV71 originated from China with complete sequence or partial sequence of VP1 were obtained from GenBank/NCBI and used for the phylogenetic trees construction using MEGA 5.0 software. The similarity of nucleotide and amino acid were estimated between groups and within groups. Results Since 1987, The strains with complete VP1 sequence had been isolated from 20 provinces, cities or regions in mainland China and showed a rapid growth trend after 2008; C-type was popular in the past more than twenty years, and A-type was only found in 2008 of Anhui and in 2009 of Hubei. Each genotype had specific variation between number 43, 58, 142, 164, 167, 184, 240, 249, and 292 amino acid residues. Compared to other C4-type strain, samples from healthy children had no specific variation in the amino acid. Conclusions C-type strain may be more infectious and the variation of the amino acids may play an important role in the evolution of EV71. It was no significant association between VP1 gene and the severity of the disease. It must strengthen the study of the cross-protection effect among C4a subtype vaccine candidate and other genotypes strain.