湖北省某中学一起诺如病毒感染性腹泻暴发疫情的调查分析

An acute gastroenteritis outbreak caused by norovirus in a middle school in Hubei province, China

目的 分析湖北省某中学一起感染性腹泻暴发疫情的流行病学特征,为制定防控措施提供依据.方法 采用现场流行病学方法,制定病例定义并开展病例搜索和调查,采集患者、厨工及相关环境样本进行实验室检测,运用描述性流行病学方法、病例对照研究方法进行分析.结果 共搜索到85例患者,罹患率为31.6％（85/269）.71.8％（61/85）的病例在2017年2月15日8：00至24：00发病.从17例患者（16名学生和1名老师）和2例隐性感染者（厨工）的肛拭子中检出GⅡ组诺如病毒核酸阳性.病例对照研究结果显示,进食2017年2月14日早餐是发病的危险因素（OR=21.77,95％CI：2.61～181.77）.结论 该次事件为一起由诺如病毒引起的感染性腹泻暴发疫情,隐性感染的厨工可能与疫情发生有关.

Objective To analysis the epidemiological characters of an infectious diarrhea outbreak in a middle school in Hubei province,and to provide evidence for prevention and control measures.Methods Field epidemiological method was used in case definition and patient search.Samples from patients,kitchen workers and related environment were collected for laboratory testing.Descriptive epidemiology and case-control study were used in the analysis.Results Eighty-five cases were identified and the attack rate was 31.6％ （85/269）.The onset time of 71.8％ （61/85） of the cases was 8：00 to 24：00 on February 15,2017.Nucleic acid of norovirus was G Ⅱ positive in the anal swabs of 17 patients （including 16 students and 1 teacher） and in 2 cases of silent infection （kitchen workers）.Case-control study suggested that breakfast on February 14,2017 was a risk factor for onset （odds ratio =21.77,95％CI：2.61-181.77）.Conclusions The outbreak was associated with contamination by norovirus.Silent infection in kitchen workers may be associated with the outbreak.