一起甲型病毒性肝炎暴发疫情的病原学诊断与基因分析

目的 查明引起2004年宁波局部地区甲型病毒性肝炎（甲肝）暴发疫情的病原并分析其基因特征。 方法 用酶联免疫吸附试验检测血清中的甲肝病毒IgM抗体（HAV IgM）和戊型肝炎病毒IgM抗体（HEV IgM），利用逆转录-聚合酶链反应（RT PCR）检测粪便样品中的HAV核酸（RNA）并扩增VP1基因，测序结果利用DNA star软件进行比对分析。 结果　172份血清样品中HAV IgM均为阳性，HEV IgM均为阴性。172份粪便样品中共检测到HAV RNA阳性样品74份，占43.0%。选择5份样品进行HAV VP1基因扩增并测序，测序结果经过比对后发现4株宁波株(NB2004-10、NB2004-11、 NB2004-51和 NB2004-71)的VP1基因是完全一致的；NB2004-75与以上4株的核苷酸的同源性为99.9％，氨基酸的同源性为99.7％；宁波株与HAV各基因型标准株比较， 与IA亚型毒株AH2的核苷酸和氨基酸的同源性最高， 分别为98.9％和99.7%～100.0％；与中国其他地区流行株比较，核苷酸和氨基酸的同源性波动于89.4%～96.7%和97.0％~100.0％。结论　引起这次肝炎暴发疫情的病原是甲肝病毒，其基因型为IA亚型，与日本株AH2、AH3亲缘关系最近，与中国其他地区流行株处于不同的进化簇上。

Etiological diagnosis and genotyping analysis of an outbreak of hepatitis A

Objective The study was conducted to identify the pathogens causing a local outbreak of hepatitis A in Ningbo in 2004 and analyze its gene characteristics.Methods HAV IgM and HEV IgM of serum samples were detected by using ELISA test;HAV RNA in stool samples was detected by RT-PCR;VP1 gene of HAV was cloned by RT-PCR and sequenced;the sequence results were analysed by DNAstar.Results All 172 serum samples were positive for HAV IgM and negative for HEV IgM,and HAV RNA was detected from 74 stool samples,accou...