某工厂1起戊型病毒性肝炎暴发调查

A hepatitis E outbreak in a factory

目的调查某省份某工厂1起戊型病毒性肝炎(戊肝)暴发的发生原因。方法通过病例搜索、病例和对照问卷调查、卫生学调查,了解暴露因素和传播过程;采用血清学和基因检测,确定戊肝病毒(HEV)感染和基因型。结果本次暴发中该工厂职工的戊肝罹患率为5.53%(22/398),暴发持续时间为25d。工人的两个居住小区罹患率分别为6.56%、8.28%(χ2=0.28,P=0.60);工厂9个车间罹患率为2.70%-28.00%(χ2=23.19,P=0.003);男、女罹患率分别为7.58%、0.83%(χ2=7.36,P=0.007);各年龄组罹患率为4.00%-8.70%(χ2=0.81,P=0.85)。病例组和对照组饮用桶装水比例分别为33.33%、27.12%(χ2=0.17,P=0.677),食用食堂以外可疑食物比例分别为16.67%、8.47%(χ2=0.21,P=0.644)。疫情发生前2个月内食堂存在多次猪内脏食品未完全做熟现象。工厂职工血清抗HEV-IgG阳性率为13.94%(63/452),其中1份血清HEV-RNA阳性,鉴定为4型HEV。结论本次暴发由4型HEV基因型引起,可能通过食用未熟的猪内脏食品传播。

Objective To determine the causes of a hepatitis E outbreak in a f actory of a province.Methods We conducted case searching,case and control investigation,and hygiene investigation to identif y exposure factors and transmission patterns.We used serological and genetic tests to determine infections with,and genotypes of hepatitis E virus(HEV).Results The outbreak among factory workers lasted 25 days and had an attack rate of 5.53%(22/398).Attack rates were 6.56%and 8.28%(χ2=0.28,P=0.60)in two workers’living areas;2.70%-28.00%(χ2=23.19,P=0.003)in 9 factory workshops;7.58%and 0.83%(χ2=7.36,P=0.007)for males and females,respectively;and 4.00%-8.70%(χ2=0.81,P=0.85)by age group.One third(33.33%)of cases and 27.12%of controls(χ2=0.17,P=0.677)had consumed water f rom a barrel,and 16.67%of cases and 8.47%of controls(χ2=0.21,P=0.644)had eaten suspicious food outside the factory canteen.The pig offal served in the canteen had not been f ully cooked several times within the 2 months prior to the outbreak.13.94%(63/452)of factory workers were positive to anti-HEV-IgG;one worker was positive to HEV-RNA,which was identified as genotype 4 of HEV.Conclusions The outbreak was caused by HEV genotype 4 and was likely transmitted through eating improperly cooked pig offal.