一起敬老院戊肝暴发疫情的流行病学调查

Outbreak of hepatitis E among aged people in a nursing home

目的了解一起敬老院戊型肝炎(HE)暴发疫情的可能传染源,明确该起疫情的病原特点。方法对疫点和相关人员进行现场访谈和病例对照研究,并采集116人份血标本进行抗-HEV IgM和抗-HEV-IgG检测,通过RT-PCR对病毒感染者和可疑传染源进行HEV RNA检测和序列分析。结果本次疫情共发病19例,亚临床感染11人。病例对照研究显示是否使用公共餐具P=0.062,自带餐具者无感染;人源、水源、猪源HEV毒株均为HEV-Ⅳd亚型,水源和人源毒株同源性100%,人源毒株与猪源同源性93.7%～95.5%。该敬老院自养生猪和自种菜地并施粪肥;食堂操作不规范,可能导致携带HEV的猪粪或污水污染餐具,是引起本起疫情的原因。结论该起暴发疫情与当地生猪HEV病毒携带率高,疫点食堂卫生管理欠规范有关。

To elucidate cause of the Hepatitis E（HE） outbreak in a nursing home and determine the genotype of the hepatitis E virus.Face to face questionnaires and case control study were used in this investigation.Of 116 sera from all the members of the nursing home were collected and tested for anti-HEV IgM and anti-HEV IgG.The HEV RNA was detected in HEV IgM positive sera and 30 fece and bile samples from swine and 6 water sample from nearby river were detected by RT-PCR and then sequenced.Totally there were 19 HE cases and 11 people were subclinical infected by HEV.Using public table-wares in the refectory might be the risk factor of infection（P=0.062,exact）.Nobody was infected in 10 persons who used private dish.HEV isolated from patients,water and swine were all categorized to genotype 4d.HEV isolated from patients and water shared 100% sequence homology and the homology was 93.7%-95.5% between HEV from human and swine.Swine were raised and vegetables was planted in this nursing home.Swine feces were often fertilized on garden.Also food service sanitation was poor.Contamination of public tablewares in the refectory by HEV infected feces or water might result in this outbreak.The high HEV infection rate in local swine and the poor sanitation in refectory was the cause of this outbreak.