江苏某小学一起诺如病毒引起的胃肠炎暴发疫情分析

An outbreak of Norovirus gastroenteritis in a primary school of Jiangsu Province

目的调查和分析江苏省某小学一起胃肠炎暴发的病原和传播危险因素,为采取针对性预防控制措施提供依据。方法制定病例定义,运用描述性和分析性流行病学方法对暴发疫情流行特征和危险因素进行分析,采集病例、桶装水及环境有关标本,进行可疑病原体PCR核酸检测,并对部分阳性标本进行测序分析。结果该起事件共报告病例78例,罹患率为2.44%。病例对照研究结果显示,接触病例、暴露过患者的呕吐物是发病的可能危险因素（χ^2值分别为18.20,27.18,P值均〈0.05）;洗手时用洗手液或肥皂（χ^2=6.17,P=0.013）为保护因素。11例病例的肛拭子标本5份检测出诺如病毒GII.4型阳性。结论该起事件为由诺如病毒GⅡ.4型感染所致的急性胃肠炎暴发。密切接触和暴露于患者的呕吐物可能是此次暴发的主要危险因素。

Objective To investigate an outbreak of gastroenteritis in a school and to identify pathogen as well as risk factors of infection for intervention strategies. Methods Epidemiological characteristics and risk factors of the outbreak were decrypted and analyzed. Case specimens,bottled water and environmental samples were collected for PCR（ polymerase chain reaction）test on suspected pathogen,and genotypes were determined by sequence analysis. Results There were 78 patients in the school and the attack rate was 2. 44%. The case-control study showed that direct contact with infected（ χ^2= 18,P 〈0. 05）,exposed to vomit（ χ^2= 27. 18,P 〈0. 05） were risk factors,while washing hands with soap（ χ^2= 6. 17,P = 0. 013） was protective factors. Among the 11 rectal swabs,5 were positive for Norwalk GII viral. Conclusion The incident of an acute gastroenteritis is caused by Norwalk GII. 4 virus infection. Closed contact and exposure of patients vomit are the major risk factors of the outbreak.