江西省某农村一起因水源污染导致的伤寒暴发疫情调查分析

Survey on a typhoid outbreak caused by contaminated water in rural area in Jiangxi province

2010年9月28日,江西省于都县黄坑村发生25例疑似伤寒病例。为查明病因和传播途径,开展了本次调查,结果黄坑村共搜索到40例病例(疑似病例25例,确诊病例15例),39例(98%)在沉坑组居住,沉坑组罹患率(34%)明显高于其他村民组(0.34%)(RR=983,95%CI:136～7096)。沉坑组居民中使用沉坑山水源村民的罹患率(42%)显著高于使用其他水源村民的罹患率(4%)(RR=11,95%CI:2.1～160)。对使用沉坑山水源村民的队列研究显示,饮用生水者发病风险高于饮开水或桶装水者(RR=2.5,95%CI:1.1～7.9)。饮用生水者中,饮水剂量与发病风险呈现剂量反应关系(线性趋势χ2=5.7,P=0.016)。环境卫生调查发现,沉坑山水源为山渗水,无任何安全保护措施,6份水源水样标本检测总大肠菌群和粪大肠菌群均超标。15例病例Tubex检测伤寒IgM均阳性。本次伤寒暴发的危险因素是饮用受污染山渗水的生水。

On 28 September 2010,26 suspected typhoid cases were reported in a village in Jiangxi province.The survey was conducted to identify its cause and mode of transmission and provide evidence to control the outbreak.The case definition was made.The cases were searched by household interview after checking medical records in local health care facility.The survey on drinking water was conducted to understand the category of drinking water,villagers＇ drinking volume,relative risk of different drinking water and dose response relation of drinking unboiled water.The serological detection of IgM antibody to Salmonella typhi was conducted with Tubex assay.Totally 40 cases were found in the village,including 25 suspected cases and 15 confirmed cases;39 cases（98%） were in group Chenkeng of the village.The attack rate in group Chenkeng（34%） was significantly higher than that in other groups（0.34%）（RR=983,95%CI：136-7096）.In group Chenkeng,the attack rate in the villagers who drank water from Mountain Chenkeng（42%） was significantly higher than that in those who drank water from other source（4%,）（RR=11,95%CI：2.1-160）.The retrospective cohort study showed that among the villagers who drank water from Mountain Chenkeng,those who drank unboiled water had higher disease risk（RR=2.5,95%CI：1.1-7.9）.Among the villagers who drank unboiled water,the dose response relation with the disease was observed（χ2 test for trends： 5.7,P=0.016）.Environmental survey indicated that the water from Mountain Chenkeng was contaminated.The total coliforms and fecal coliforms in 6 water samples taken at the source water exceeded the limit for drinking water.The IgM antibody to Salmonella typhi was detected in 15 confirmed cases with Tubex assay.The cause of the typhoid outbreak was identified as drinking unboiled,contaminated water from Mountain Chenkeng.It is suggested that the government should take measures to protect the water source in rural area to prevent the incidence of waterborne diseases.