Hepatitis E virus (HEV) genotype and the prevalence of anti-HEV in 8 species of animals in the suburbs of Beijing

目的 调查北京地区与人密切接触的猪、牛、羊、马、驴、犬、鸡、鸭8种动物血清中戊型肝炎病毒(HEV)抗体流行率及该地区猪HEV基因型和亚型.方法 收集8种动物的血清标本及幼猪粪便标本,用双抗原夹心ELISA法检测血清中抗-HEV;用巢式反转录聚合酶链反应法(RT-nPCR)检测HEV RNA;对部分PCR产物进行克隆和测序,并对测序结果进行基因分型.结果 在8种动物中抗-HEV阳性率分别为猪80.43%(481/598),其中成猪(>6月龄)为87.86%(369/420),幼猪(2～3月龄)为62.92%(112/178);牛15.02%(52/346);马14.29%(40/280);驴0(0/26);羊9.88%(33/334);犬0(0/21);鸭3.03%(7/231);鸡2.53%(8/316).RT-nPCR检测3月龄以下猪粪便标本HEVRNA阳性率为66.67%(74/111).HEV RNA阳性的标本测序后可归为6株(分别命名为bjsw1、bjsw2、bjsw3、bjsw4、bjsw5和bjsw6),6株HEV开放读码框2(ORF2)部分核苷酸序列的相似性为94.5%～99.6%,与1、2、3、4型HEV的相似性分别为75.6%～78.6%、75.6%～76.2%、77.1%～80.7%和83.7%～94.5%.6株HEV与人HEV 4d亚型的同源性最高,为90.0%～94.5%.结论 北京市郊区猪、牛、马、羊、鸭、鸡中均存在HEV感染,其中猪抗-HEV流行率最高,驴、犬抗-HEV的流行率最低;6株猪HEV属于基因4型、4d亚型.Objective To investigate the prevalence of anti-hepatitis E virus (HEV) and genotypes of hepatitis E virus in 8 species of animals including swine, cattle, sheep, horse, donkey, dog, chicken and duck in the suburb of Beijing. Methods Serum samples were collected from the 8 species of animals, and fecal samples of younger swine were collected from 2 stock farms. Anti-HEV was detected by Double Antigen Sandwich Assay. HEV RNA from fecal samples was detected by a reverse transcription nested polymerase chain reaction (RT-nPCR). Parts of the PCR products were cloned and sequenced. The swine HEV sequences were analyzed genetically. Results The positive rates of anti-HEV in serum specimens of swine, cattle, horse, donkey, sheep, dog, duck and chicken were 80.43%(481/598), 15.02%(52/346), 14.29%(40/280) ,0(0/26) ,9.88%(33/334), 0(0/ 21) ,3.03% (7/231) and 2.53%(8/316), respectively. The anti-HEV prevalence of adult swine(≥6 months)and younger swine(≤3 months)were 87.86%(369/420)and 62.92%(112/178)respectively. 74 of 111 (66.67% ) pig faces were positive for HEV RNA. Sequence analysis on these positive samples showed that there were 6 groups of HEV designated as bjsw1, bjsw2, bjsw3, bjsw4, bjsw5 and bjsw6. The 6 strains of HEV shared 94.5%-99.6% sequence identity of partial HEV ORF2 nucleotide with each other. The identities of HEV ORF2 nucleotide sequences between the 6 strains and genotype 1, 2, 3 and 4 were 75.6%-78.6% , 75.6%-76.2%, 77.1%-80.7% and 83.7%-94.5%, respectively. The sequence identity between the 6 strains and human HEV genotype 4d was 90.0%-94.5% . Conclusion HEV infection was seen in swine, cattle, horse, sheep, duck and chicken in the suburbs of Beijing. The anti-HEV positive rate appeared the highest in swine and the lowest in dog and donkey. The six strains of HEV isolated from younger swine belonged to genotype 4d.国家高技术研究发展计划(863计划); 国家自然科学基金PubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)0147-503