一起学校伤寒水型暴发的流行病学调查

Epidemiological Investigation on Outbreak of Waterborne Typhoid in a Middle School

[目的 ]查明某中学 2 44例伤寒暴发原因、传播方式 ,以扑灭疫情。[方法 ]对其中的 88例进行 1∶1病例对照研究 ;对血和粪进行培养。[结果 ]病例全部为学生 ,罹患率 18 5 %。住校生罹患率 ( 3 0 % )高于走读生 ( 10 % , 2 =86 17,P <0 0 1)。病例性别、班级和寝室分布无聚集性。在校经常喝生井水与本次疫情有联系 (OR =13 2 ,95 %CI为 4 5 7～41 0 5 )。学校饮用井水受到人、畜粪便的严重污染 ,大肠菌群、细菌总数严重超标。 40 %的病人血或粪便标本中分离到伤寒杆菌。[结论 ]本疫情为学生喝严重污染的生井水导致的一起伤寒水型暴发流行。加大农村地区改水、改厕工作力度 ,加强学校饮用水、食堂卫生安全监督、监测和健康宣教工作 。

To investigate the cause and transmission of waterborne typhoid outbreak (244 cases) in a middle school. A case-control study was carried out for 88 cases (1∶1) and the blood and feces were cultured for typhoid bacillus. All patients were students. The incidence rate was 18.5%. The rate of students living in school (30%) was higher than that living at home (10%) (P<0.01). The case distributions did not show clustering for sex, classroom and living-room. The main risk factor for typhoid was un-boiled well water drinking in school ( OR=13.2,95% CI =4.57-41.05). The well water pollution was by feces badly and shown seriously higher coli-form group and total bacteria count. The outbreak of waterborne typhoid in a middle school is caused by well water pollution. It is very important to enforce the supervision and surveillance for drinking water, toilet sanitation, food safety and health education for typhoid control and prevention.