一起高校诺如病毒感染性腹泻暴发疫情流行病学调查

Epidemiological investigation on a norovirus outbreak in one university

目的了解某高校诺如病毒感染性腹泻暴发疫情流行病学特征,分析疫情病因,为预防和控制疫情提供参考。方法采用现场流行病学调查及实验室检测方法,对病例进行回顾性调查。运用描述性统计分析、病例对照研究方法对暴发疫情数据及相关因素进行分析。结果本次疫情共持续14 d,首发病例发病时间为12月22日13：00,累计发病92例。92例病例中,本科生罹患率为1.57%（62/3 945）,研究生罹患率为0.76%（26/3 424）,教职工罹患率为0.26%（4/1 560）,差异有统计学意义（χ^2=23.20,P〈0.01）。男性罹患率为1.28%（72/5 614）,女性罹患率为1.14%（20/1 755）,性别差异无统计学意义（χ^2=0.22,P〉0.01）。92例病例主要症状为腹泻（73.91%,68/92）、恶心（71.74%,66/92）、腹痛（63.04%,58/92）、呕吐（59.78%,55/92）、发热（42.39%,39/92）。学生食堂M餐厅为疫情暴发高危场所（OR=3.72,95%CI=1.67~8.23）。实验室检测发现3名学生病例粪便样和1名厨工肛拭子样标本检出诺如病毒,其中2名学生病例均有M餐厅就餐史。结论该疫情为一起由M餐厅共同暴露引起的诺如病毒感染性腹泻暴发疫情,食物传播为主要传播途径。

Objective To conduct epidemiological investigation and analysis on a norovirus outbreak in one university. Methods Cases were retrospectively investigated by using field epidemiological investigation. Descriptive and ease-control statisti- cal method was used to analyze the outbreak data and to explore associated risk factors. Results The outbreak lasted 14 days. There were a cumulative total of 92 reported cases of norovirus after the onset of initial case in 22 December 2014. Among them, at- tack rate among undergraduates, graduates and faculty members were 1.57%, 0.76% and 0.26%, respectively. Symptoms and signs of norovirus infection include vomiting, watery diarrhea, and stomach pain. Student canteen was the high-risk place of the outbreak { OR= 3.72, 95%CI= 1.67-8.23）. Norovirus was detected from fecal sample of 3 students and the anal swab of one cook by labora- tory detection. Conclusion The epidemic is a diarrhea outbreak caused by norovirus which transmitted primarily by food.