贵州省旱灾期间一起甲型病毒性肝炎爆发的流行病学调查

An Epidemiological Investigation of Hepatitis A Outbreak during the Period of Severe Drought in Guizhou Province

目的调查贵州省黔西县甲型病毒性肝炎(甲肝)爆发疫情,查找危险因素和传播途径,提出针对性预防控制措施。方法 2010年1月1日～4月19日,疑似为甲肝病例的黔西县居民,同时具备以下2个条件者:①出现无其他原因可解释的发热、乏力、纳差、厌油、腹胀、肝区疼痛中的任何2项,或出现黄疸(巩膜、皮肤或尿液黄染);②丙氨酸氨基转移酶≥2倍升高。确诊甲肝病例为疑似甲肝病例、且抗甲肝病毒免疫球蛋白M阳性者。通过查阅医院门诊记录等方式搜索病例。开展病例对照研究,比较两组水源、饮水习惯、饮食、洗手等的差异。结果共搜索到254例甲肝病例,GT乡和CG镇病例数分别占62%和31%,病例集中在5～20岁人群。流行曲线呈现两个高峰,为点源暴露模式。饮用LT河自来水[比值比(Odds Ratio,OR)=2.8,95%可信区间(Confidence Interval,CI):1.2～6.7]和喝生水(OR=8.4,95%CI:3.4～21.2)是发病的危险因素。LT河自来水检测细菌总数>190菌落形成单位/毫升(ml),总大肠菌群>1600最大或然数/100ml。结论此次甲肝爆发系饮用被污染的LT河自来水所致,要加强自来水消毒和卫生监督。

Objective A hepatitis A outbreak in Guizhou province was investigated to identify risk factors and mode of transmission, and to provide control and prevent measures. Methods A suspected case was defined as onset between January 1 and April 19, 2010 with 2-fold increase in alanine aminotransferase and 〉 2 of the followings： fever, malaise, anorexia, nausea, abdominal discomfort and jaundice in a resident of the Qianxi county. A confirmed case was a suspected case with antibody to hepatitis A virus immunoglobulin M positive. Cases were searched in the hospitals, villages and schools. In a case- control study, the exposures to sources of water, drinking habits, food and washing hands were compared. Results 254 hepatitis A cases were identified. 62% and 31% cases occurred respectively in GT and CG towns. Most cases were 5-20 years old. The two peaks of the outbreak showed in the epidemic curve were related to the exposure of the source of origin. 91% of the cases and 77% of controls drank LT river water [ Odds Ratio （OR）=2.8, 95 % Confidence Interval （CI） ： 1.2 6.7 ]. 79 % of the cases and 32 % of controls drank unboiled water （OR=8.4, 95 % CI ： 3.4 21.2）. The total bacterial count was 〉 190 colony- forming units （cfu）/ml and the total coliform was 〉 1600 most probable number （MPN）/100 ml in the LT river water. Conclusion Drinking unboiled contaminated water was responsible for the outbreak. Local government should supply chlorinated water and strengthen supervision of quality of water.