固定人群10年间戊型肝炎病毒分子进化特征研究

Based on an established active hepatitis surveillance system, hepatitis E virus infected subjects over 10 consecutive years in Dongtai were identified. The nucleic acid sequence of the RDRP district of HEV ORF1 and ORF2 were obtained from the HEV RNA positive samples, and HEV full-length gene amplification were conducted on the representative strains with the methods of segmented amplification. After the homology comparison to the reported standard sequence of various genotypes and subtypes and the construction of phylogenetic tree, HEV genotypes and subtypes epidemic variation characteristics, gene mutation hotspots and positive or negative selection sites in the same area for 10 consecutive years, HEV epidemic strains' molecular evolutionary rate in the same area and the virus' genetic characteristics in different liver injury severity groups were then analyzed. And thus reflect the comprehensiveness of the HEV's genetic information, provide a more reliable theoretical and technical support to the prevention and early warning to hepatitis E.

基于已建立的疑似肝炎主动监测系统，通过收集东台地区连续10 年间戊肝病毒感染人群，对核酸筛查阳性的标本分别获得HEV ORF1 段的RDRP 区和ORF2 段的核酸序列，并对部分代表株采用分段扩增法进行HEV 全长基因的扩增，与已报道的各基因型和亚型的标准序列进行同源性比对，并构建进化树，分析同一地区连续10 年间HEV 基因型及亚型的流行变化特征，基因突变热点及正负选择位点，同一地区HEV 流行株分子进化速率和不同肝损伤严重程度人群中HEV 的基因特征，进而体现HEV遗传信息的全面性，为戊肝的预防和预警提供更为可靠的理论和技术支撑。

本研究基于已建立的疑似肝炎主动监测系统，通过收集东台地区连续10 年间戊肝病毒感染人群，对核酸筛查阳性的标本获得HEV ORF1 段的RDRP 区核酸序列，与已报道的各基因型和亚型的标准序列进行同源性比对，并构建进化树。分析同一地区连续10 年间HEV 基因型及亚型的流行变化特征可见：1）自2011年之后未发现HEV 1型感染；2）基因亚型进化可见以HEV 4a和4d感染为主，后期有可能往4h和4j发展；3）肝损伤轻微的多以1型感染为主，4型及其亚型感染后肝损伤较为严重；4）HEV的病毒载量与其肝脏损伤严重程度的呈一定的正相关。结合本课题实验室检测结果，对参加戊肝疫苗三期临床试验的戊肝病例进行确诊，分析发现戊肝疫苗长期保护性较好，8年保护率为91.7%(79.3%-96.7%)。本研究阐明了在一个相对固定人群中持续多年的HEV流行特征和分子进化规律，为戊肝病毒流行的预防和预警提供基础数据和科学依据。