四川省甘孜州藏猪戊型肝炎病毒分子流行病学调查

Molecular Epidemiology of Hepatitis E Virus in Tibetan Pigs in Ganzi Prefecture,Sichuan Province

为了解甘孜州藏猪戊型肝炎病毒(HEV)的感染情况,分析其相似性和遗传进化关系。本试验用反转录套式聚合酶链反应(RT-nPCR)方法对采集于2018-2019年甘孜藏族自治州藏猪主要养殖区域4个县10个藏猪养殖场的229份藏猪粪便样本进行核酸检测,并对全部阳性样本进行ORF 2基因部分片段扩增测序,遗传进化分析。结果显示:猪粪便HEV核酸阳性率为16.59%(38/229,95%CI=12.00%~22.10%),猪场HEV阳性率为70%(7/10,95%CI=34.8%~93.3%);38个ORF 2基因片段彼此之间核苷酸序列相似性为76.1%~100.0%,推导的氨基酸序列相似性为79.6%~100.0%,系统进化树分析显示所有阳性毒株均为基因4型,且与人源HEV毒株亲缘关系近。结果表明甘孜州藏猪中存在一定程度的HEV感染,与人源HEV毒株遗传关系近,相关部门采取防控措施以降低HEV感染的公共卫生风险。

This study investigated the epidemiology and genetic evolution of hepatitis E virus(HEV)in Tibetan pigs in Ganzi prefecture.RT-nPCR was used to detect 229 fecal samples from 10 Tibetan pig farms in 4 counties of Ganzi prefecture from 2018 to 2019,and all positive samples were amplified and sequenced by partial ORF 2 gene fragments,and the genetic evolution was analyzed.The results of RT-nPCR showed that 16.59%(38/229,95%CI=12.00%-22.10%)of fecal samples were HEV positive,and 70%(7/10,95%CI=34.8%-93.3%)of 10 Tibetan pig farms had HEV positive pigs.The nucleotide sequence similarity of ORF 2 was 76.1%-100.0%,and the deduced amino acid sequence similarity was 79.6%-100.0%.Phylogenetic tree analysis showed that all the positive strains were genotype 4 and had the closest genetic relationship with human HEV strains.Thus,HEV displaying close genetic relationship counterpart is present in Tibetan pigs in Ganzi prefecture,and comprehensive prevention and control measures are required to reduce public health risk of HEV infection.