一起因厕所卫生不良致诺如病毒感染性腹泻暴发的调查

An outbreak of infectious diarrhea with noroviruses caused by poor toilet hygiene

目的调查和分析安化县一起中学诺如病毒感染性腹泻暴发疫情,探讨其传播途径和方式,为制定防控措施提供科学依据。方法对2014年2月18日-3月2日安化县某中学感染性腹泻暴发疫情腹泻病例进行个案调查和现场流行病学调查、分析,并对采集的标本进行实验室检测。结果调查发现感染性腹泻病例105例,罹患率为3.04%,主要症状为腹泻、腹痛、恶心、呕吐;离厕所近的教室学生罹患率较高,教职工与学生、男女生之间罹患率差异有统计学意义(P<0.05),走读生和寄宿生之间差异无统计学意义(P>0.05);实验室检测发现诺如病毒核酸阳性标本12份,其中Ⅰ型5份,Ⅱ型3份,Ⅰ型和Ⅱ型混合感染4份。结论这是一起由诺如病毒感染所致的感染性腹泻暴发疫情,教室厕所卫生设计不良,致气溶胶产生和传播是此次暴发的主要传播途径。

Objective To investigate and analyze the epidemic situation of an outbreak of infectious diarrhea with noroviruses in a middle school in Anhua County, to explore the routes and ways of transmission, and to offer scientific evidence for formulat- ing prevention and control measures. Methods We conducted case survey and field epidemiological investigation and analysis based on an outbreak of infectious diarrhea with noroviruses in a middle schoo! in Anhua County from February 18 to March 2, 2014. And the samples collected from the field were detected. Results There were 105 cases of infectious diarrhea con- firmed, with the attack rate of 3.04 %. The main clinical manifestations were diarrhea, stomachache, nausea and vomiting. The students whose classrooms were near the toilets had a higher morbidity. There were statistically significant differences in the mor- bidity between teaching staff and students as well as between males and females （P 〈 0.05）, but no statistically significant differ- ence was found between day students and boarding students （P〉0.05）. 12 samples were found to be positive for noruvirus RNA, including 5 samples with noruvirus GI, 3 samples with norovirus GII and 4 samples with norovirus GI and GII co- infection. Conclusions It is an outbreak of infectious diarrhea induced by noroviruses. The generation and transmission of aerosol caused by the poor sanitation design of the classrooms and toilets is the main transmission route of this outbreak.