云南某农村猪戊型肝炎病毒分子流行病学调查

Molecular epidemiology of swine HEV in a village of Yunnan

目的了解云南农村散养猪群HEV感染情况,为HEV防控提供理论依据。方法利用逆转录巢式聚合酶链反应(RT-nested PCR)技术,对所采集云南猪群78份粪便样品进行HEV ORF2基因部分片段扩增,经琼脂糖凝胶电泳后对目的条带进行回收纯化及克隆测序。序列利用DNAStar和MEGA4.0软件进行同源性比较和系统进化树构建。结果 RT-nested PCR方法扩增出了350bp目的基因序列,该序列与GenBank中HEV各型的同源性在77.4%～97.4%之间,与基因4型同源性最高(97.4%),与3型同源性最低(77.4%)。系统进化树显示测定的序列与基因4型聚为一支,表明该序列属于基因4型。本次实验共检测了78份猪粪便样品,其中8份为阳性,阳性率为10.26%。结论云南农村人群存在感染HEV的风险,应该加以防控以免HEV暴发流行。

To investigate the prevalence of swine HEV in rural areas of Yunnan province,78 swine stool samples were collected from a village of Yunnan for HEV ORF2 detection by Reverse Transcription-nested PCR（RT-nested PCR）.The PCR products were detected by electrophoresis on agarose gel and purified,and then cloned into pMD18-T vector and sequenced.The homology and phylogenetic tree were analyzed by DNAStar and MEGA 4.0,respectively.Results indicated that the expected 350 bp fragments were obtained,which shared 77.4%~97.4% homologies with different HEV genotypes,97.4% with genotype 4 and 77.4% with genotype 3.Phylogenetic analysis suggested that the HEV isolates in this study were clustered together with genotype 4 reference isolates,which means these isolates belonged to genotype 4.In the present study,8 samples were positive to swine HEV,and the positive rate was 10.26%（8/78）,which indicated a high risk of HEV infection to humans through the zoonotic transmission.