扬州市戊型肝炎病毒基因特征分析

Genetic identification and characterization for strains of human and swine hepatitis E virus in Yangzhou City

目的分析扬州市戊型肝炎病毒（hepatitis E virus,HEV）的基因特征。方法采用反转录-聚合酶链反应（reverse transcription-nested polymerase chain reaction,RT-nPCR）法筛选人抗戊型肝炎（hepatitis E,HE）病毒抗体免疫球蛋白m（immunoglobulin m,IgM）阳性血清和猪肝组织样品,套式RT-PCR扩增HEV RNA ORF2片段基因并测序,DNA Star MegAlign比对核苷酸构建距离矩阵和系统发生树。结果筛查并扩增6株基因4型HEV病毒,核苷酸同源性89.9%~99.3%,与基因4型参考株的同源性为85.8%~94.6%,与其他基因型的同源性为79.1%~89.2%,遗传进化显示扬州市6株病毒分在3个基因亚型分支上,与基因2型和3型的遗传距离大于基因1型。结论扬州地区人源和猪源HEV同源性高,HE的传染源是猪的可能性大。

Objective To investigate the genetic characteristics of hepatitis E virus in Yangzhou City. Methods The pig liver and the serum samples of patients with positive anti-HEV IgM were collected and detected for HEV RNA by using real-time PCR. The HEV RNA ORF2 PCR products were obtained by nested RT-PCR and sequenced for polygenetic analysis. The nucleotide identity between sequences was calculated and sequence alignments were made to generate distance matrix and phylogenetic trees using DNAStar MegAlign. Results Six HEV strains were isolated,genotype IV RNA was noted,and their HEV ORF2 sequences were amplified. Within these six isolates,the nucleotide identity of HEV ORF2genes ranged from 89. 9 %-99. 3%. The nucleotide identity between these 6 isolates and the genotype-IV and other genotype reference strains from GenBank were 85. 8%-94. 6% and 79. 1%-89. 2% respectively. Polygenetic analysis revealed that these six isolates scattered in three sublineage. The sequence distance from the 6 isolates to genotype Ⅱ and Ⅲ was longer than that from the 6 isolates to genotype Ⅰ. Conclusions The HEV isolates from human and swine in Yangzhou share a high homology of nucleotide. Swine can be taken as a principal reservoir of hepatitis E virus that infects humans.