2014年广州某大学一起诺如病毒感染性腹泻暴发疫情的调查分析

Investigation and analysis on an outbreak of infectious diarrhea caused by norovirus in an university in Guangzhou in 2014

目的对一起大学诺如病毒感染性腹泻暴发疫情开展流行病学调查,探讨疫情暴露因素和感染来源,提出有效防控措施。方法对病例进行描述性流行病学分析,以临床病例为病例组,选取病例同宿舍楼内未发病的健康学生为对照组,比较两组不同就餐食堂、不同就餐餐次暴露的差异,探查病例危险因素。结果累计报告病例64例,学生罹患率为0.35%(64/18490),145份样品中检出36份诺如病毒核酸阳性,病例阳性检出率为57.89%(22/38),厨工阳性检出率为13.08%(14/107);诺如病毒分型均为GⅡ.4型。可疑暴露食堂、餐次是第三食堂2月26日晚餐(OR=5.00,95%CI:1.02-24.49)和第三、五食堂2月28日晚餐(OR=6.65,95%CI:2.11-20.93;OR=5.73,95%CI:1.19-27.60)。结论引起本次疫情的原因是该校厨工在加工食物/分发餐具时污染了食物/餐具引起的诺如病毒传播。

Objective Take an epidemiological investigation for norovirus infectious diarrhea in a university, to explore the exposure factors and sources of infection, and provide the effective measures to prevent and control the event. Methods Descriptive epidemiological analysis was carried out on the cases-control study. The cases were clinical patients and the controls were health students who lived in the dormitory with the patients. The different dining canteen and different person-times of exposure were compared between case group and the control group, probing cases exposures. Results Sixty-four cases were reported and the attack rate in students was 0.35% (64/18490).Norovirus nucleic acid was positive in 36 of the total 145 samples, in which the positive detection rate of cases and cooks was 57.89% (22/38) and 13.08% (14/107) respectively. Norovirus typing was all GⅡ.4.Suspicious exposed sources were the dinner of February 26in the third dining canteen (OR=5.00,95%CI:1.02-24.49) and dinner of February 28 in the third (OR=6.65,95%CI:2.11-20.93) and fifth (OR=5.73,95%CI:1.19-27.60) dining canteen. Conclusion The main cause of the outbreak was likely to be the spread of the virus of food or utensils which contaminated by kitchen staff in the school processed foods or distribute tableware.