新疆猪粪便戊型肝炎病毒RNA的检测及序列分析

Detection and Analysis of Partial Sequences of Swine Hepatitis E Virus in Xinjiang

从戊型肝炎病毒(HepatitisEvirus,HEV)IgG检测阳性的新疆某猪场采集70份猪粪便,利用逆转录套式聚合酶链方法(RT-nPCR),检测HEVRNA,其中13份为阳性,阳性率18.57%。将PCR扩增产物克隆到pMD18-T载体上,构建成重组质粒并测序,结果表明,13株猪源HEV分离株在HEVORF2348bp核苷酸序列的同源性为97.1%～100%,为同一基因型;与HEVⅠ、Ⅱ、Ⅲ、Ⅳ的同源性分别为74.1%～77.6%,71.6%～74.1%,73.3%～78.2%和82.8%～91.4%,与ⅣA亚型的同源性同源性最高达89.4%～91.4%。以该核苷酸片段绘制的基因进化树显示13株猪源HEV与HEVⅣT1株在同一分支上,属基因Ⅳ型;与国内其他猪源HEV分离株该片段核苷酸序列的同源性为82.6%～91.3%,提示中国猪源HEV的基因型比较一致,同属HEVⅣ型。

To investigate Hepatitis E virus,(HEV) infection in swine in Xinjiang and the extent of genetic variation among Chinese swine HEV strains, seventy pig fecal samples from an anti-HEV positive farm in Xinjiang were tested for the presence of HEV RNA by reverse transcription nested polymerase chain reaction (RT-nPCR). Thirteen of 70 (18.57%) pigs were positive for HEV RNA. The nucleotide sequence of 348bp region within open reading frame 2(ORF2) of the 13 swine HEV isolates was determined. The DNAstar software was used for nucleotide sequences analysis. Sequence comparison showed that 13 swine HEV isolates shared 97.1%～100% nucleotide sequence identities and 74.1%～77.6%, 71.6%～74.1%, 73.3%～78.2%, and82.8%～91.4% homogeneity to human HEV genotypes Ⅰ,Ⅱ,Ⅲ and Ⅳ, especially had a 89.4%～91.4% identity to Chinese human HEV subgenotype ⅣA. Phylogenetic analyses further revealed that these swine HEV isolates were closely related to HEV ⅣA isolated from patients with acute hepatitis. Meanwhile these swine HEV isolates had 82.6%～91.3% homogeneity to other Chinese swine HEV and were grouped into genotype Ⅳ. Our findings further support the hypothesis that swine reservoirs for HEV infection.