我国部分地区禽戊型肝炎病毒分子流行病学分析

Molecular Epidemiological Analysis on Avian Hepatitis E Virus in Some Regions of China

为了解我国鸡群中禽戊型肝炎病毒(avain hepatitis E virus,aHEV)的分子变异情况,对2018年从山东、河南、河北、辽宁、吉林、黑龙江、陕西、山西、江苏等地疑似aHEV感染鸡群中采集的679份肝脏、脾脏病料样品进行RT-PCR检测,从中选取PCR阳性产物,对其ORF1基因进行序列测定与遗传进化分析。结果显示:从病料中检出阳性样品37份,阳性检出率为5.45%;选取的15个试验毒株之间的ORF1基因同源性为90.1%~100%,与目前报道的4种基因型同源性均小于90%,其中与基因1型的澳大利亚株和韩国株同源性为85.5%~89.0%,与基因2型的美国原型株和美国无毒株同源性为85.5%~88.2%,与基因3型的欧洲株和中国株同源性为86.3%~89.7%,与基因4型的匈牙利株和中国台湾株同源性为86.4%~88.5%。ORF1基因进化树分析发现,所分离的aHEV均属于戊型肝炎B种,不在目前所划分的基因型分支上,形成独立的基因分支,不属于已报道的4个基因型。结果表明,目前在我国流行的aHEV是一种新基因型病毒,这为我国aHEV分子流行病学分析提供了补充和依据。

In order to investigate the variation status of avian hepatitis E virus(aHEV)in chicken in China,679 lesion samples of livers and spleens collected from the chicken suspected of being infected with aHEV in Shandong,Henan,Hebei,Liaoning,Jilin,Heilongjiang,Shaanxi,Shanxi,and Jiangsu provinces in 2018 were tested by RTPCR,from which,positive samples were selected,and their ORF1 genes were sequenced and analyzed for genetic evolution.The results showed that 37 positive samples were detected out with the positive rate of 5.45%;the homology of ORF1 genes among 15 selected strains ranged from 90.1%to 100%,and the homology with the four genotypes previously reported was lower than 90%,specifically,that with genotype 1(Australian and the Korean strains)was from 85.5%to 89.0%,that with the genotype 2(American prototype and avirulent strains)was from 85.5%to 88.2%;that with the genotype 3(European and Chinese strains)was from 86.3%to 89.7%;and that with the genotype 4(Hungarian and China Taiwan strains)was from 86.4%to 88.5%.It was found that,by phylogenetic tree analysis of ORF1 genes,all the isolated aHEV strains belonged to genotype B of hepatitis E,which was not located in current genotype branch,but a new independent branch outside of the four reported genotypes.In conclusion,the aHEV strain prevalent in China was a new genotype virus,which provided a supplement and basis for molecular epidemiological analysis on aHEV.