一起食用被污染田螺引起的霍乱疫情流行病学调查与应急处置分析

Epidemiological investigation andemergency treatment of cholera outbreak caused by consuming contaminated river snails

目的通过分析一起因食用被污染田螺引起的霍乱疫情进行流调病学调查和应急处置,为霍乱疫情防控提供科学依据。方法2023年1月1日至6月30日,广州市白云区医疗机构采用现场流行病学方法开展辖区内腹泻病例搜索,对霍乱疫情涉及病例及密切接触者开展流行病学调查,采集可疑食物和可能污染环境样本并开展溯源排查。结果本次疫情病原体为非产毒O1群小川型霍乱弧菌,涉及确诊病例1例,病例表现为腹泻、稀水样便。现场流调推测可疑饮食史为外带田螺,应急监测采样102份(密接人群肛拭子13份,水产品29份,外环境46份,污水3份,江河水样本11份),其中阳性11份(污水3份,田螺3份,田螺售卖档口外环境涂抹5份),结果均为非产毒O1群小川型霍乱弧菌。结论本起疫情为霍乱弧菌O1群引起的散发疫情,经流调溯源确定传染源为被污染田螺,传播途径为田螺未加工熟透,经食用后引起发病。本次处置提示对霍乱的高效监测能及时发现并有效阻断霍乱疫情的传播。

Objectivee To provide the scientific basis for cholera control and prevention by epidemiological investigation and emergency treatment of a cholera outreak caused by consuming contaminated river snails.Methods From January lst to June 30th,2023,field epidemiological methods were used by medical institutions in Baiyun District of Guangzhou to search for diarrhea cases in this district,to conduct epidemiological investigations for cholera cases and close contacts,and to collect samples of suspicious food and potentially contaminated environmental samples for traceability investigation.Results The pathogen of this outbreak was identified as non-toxic Vibrio cholerae O1,serotypes Ogawa,involving 1 confirmed case,with the symptoms of diarrhea and watery stools.On-site epidemiological investigations suggested that the suspected dietary history was the consumption of take-out river snails.Emergency monitoring and sampling included 102 samples(13 rectal swabs from close contacts,29 aquatic products,46 environmental samples,3 sewage samples,and 11 river water samples),of which 11 were positive(3 sewage samples,3 snail samples,and 5 environmental swabs from the snail sales counter)for non-toxic Vibrio cholerae O1,serotypes Ogawa.Conclusions The outbreak is a sporadic outbreak caused by non-toxic Vibrio cholerae O1,serotypes Ogawa.The source of infection is contaminated river snails,and transmission route is the consumption of undercooked river snails,which causes the cholerae.Systematic and efficient cholera surveillance can detect and effectively interrupt the spread of cholera epidemic.