贵州省某市X镇一起细菌性痢疾暴发的调查

目的 对2011年5月7日,贵州省毕节市X镇报告的一起菌痢暴发疫情展开调查,明确危险因素.方法 对所有的病例进行个案调查,用描述性流行病学方法分析病例分布情况,采用病例对照研究研究的方法,探讨本次暴发的危险因素.结果 从4月28日～17日共发生病例317例,总罹患率为0.63％.3个高发村寨中,使用镇自来水村寨的罹患率为3.3％,明显高于未使用镇自来水的村寨罹患率0.6％(RR=5.6,95％CI:2.9～11)；80％ (110/137)的病例和46％(64/137)的对照使用镇自来水洗碗、刷牙(OR=4.6,95％ CI:2.7～8.0); 66％ (90/137)的病例和16％ (11/137)的对照生饮镇自来水(OR=9.8,95％ CI:5.3～18),且每天饮用镇自来水量越多,发病危险性越大(x趋势2=11,P=0.00).镇自来水水源上游有村民排污、农田污水等污染源存在,水厂未经任何消毒就直接将水供给村民使用；实验室检测镇自来水细菌总数＞3 100 cfu/ml,大肠杆菌＞1 600 MPN/ml.结论 生饮或使用未经消毒的镇自来水是引起本次菌痢暴发的可能原因.建议加强对农村集中供水的消毒和监管,保证农村的用水安全卫生.

Investigation on A Water-born Outbreak of Shigella in X town in Bijie City of Guizhou

OBJECTIVE We investigated this outbreak to identify the mode of transmission and develop control measures.METHODS All cases were surveyed by using the uniform individual questionnaire.The distribution of the cases was analyzed by characteristic epidemiology,and a retrospective case-control study was carried out to investigate risk factors.RESULTS 317 patients were identified.The total attack rate WAS 3.3%.In three high-risk village,the attack rate of these villages with tapwater was 3.3%,while the rate of those haven’t tap-water was 0.6%(RR = 5.6,95%CI:2.9-11).80%(110 /137) patients and 46%(64 /137) controls habitually used the tap-water for washing bowls and brushing their teeth(OR = 4.6,95%CI:2.7-8.0).66%(90 /137) patients and 1 116%(11 /137) controls used to drinking tap-water without boiling(OR = 9.8,95% CI:5.3-18).The more volume they drunk,the higher attack rate they got(χ 趋势 2 = 11,P = 0.00).We found there were domestic and agricultural sewage discharging into the upper reach of the tap-water source.and the Water Works supplied the water to users without any sterilization.The counts of total bacterial were ﹥3 100 cfu /ml,and e.coli bacterium in the tap-water were ﹥1 600 MPN/ml.CONCLUSION Drinking without boiling or using the tap-water without any disinfection or boiling was likely to be the cause of this Shigella outbreak.We recommend disinfection of water source,strengthen the supervising of small central water supplies for rural areas.