安庆市某初级中学一起诺如病毒感染性腹泻暴发疫情调查

Investigation on an outbreak of norovirus infectious diarrhea in a junior middle school in Anqing City

目的分析安庆市一起学校诺如病毒感染性腹泻暴发疫情,探讨疫情传播途径和危险因素,为防控学校传染病疫情提供参考。方法采用流行病学调查表对病例开展流行病学调查和学校卫生学调查,并开展病例对照调查了解患者就餐情况,采集病例和采用荧光定量RT-PCR技术进行诺如病毒核酸检测。结果安庆市某初级中学发生的诺如病毒感染性腹泻暴发疫情波及全校3个年级18个班级,累计发病56例,罹患率为2.93%;男生3.94%,女生2.21%,男女罹患率差异有统计学意义(χ~2=4.443,P<0.05);发病班级呈聚集性,学校公共场所中的厕所和楼梯,可能增加学生暴露风险;5例患者肛拭子标本诺如病毒GII核酸阳性。结论该起疫情由诺如病毒GⅡ型感染,传播途径人传人,不排除存在气溶胶传播。

Objective To analyze anthe outbreak of norovirus infectious diarrhea in a school in Anqing City, and to explore the transmission routes and risk factors of the outbreak, so as to provide reference for the prevention and control of school infectious diseases.Methods Epidemiological investigation and school hygiene investigation were conducted with epidemiological questionnaires, and case-control investigation was carried out to understand the eating situation of patients.Cases were collected and norovirus nucleic acid was detected by fluorescence quantitative RT-PCR.Results The outbreak of norovirus infectious diarrhea in a junior high school in Anqing City affected 18 classes of 3 grades, with a cumulative incidence of 56 cases.The morbidity rate was 2.93%.Male students accounted for 3.94%, female students accounted for 2.21%3.94% for boys and 2.21% for girls.There was a statistically significant difference in the morbidity rate between males and females(χ~2=4.443,P<0.05).Classes with outbreaks were clustered.The incidence rate of norovirus infectious diarrhea was clustered in classes, and in public places of schools.Toilets and stairs in school public places may increase students’ exposure risk.Anal swab specimens from 5 patients were positive for Norovirus GII nucleic acid.The toilets and stairs in 5 patients were positive for norovirus GII nucleic acid.Conclusion The epidemic was caused by Norovirus GII infection and transmitted from person to person.Aerosol transmission was not excluded.