霍乱流行区江河霍乱弧菌污染的监测和消除研究

目的：全面掌握霍乱流行区江河段霍乱弧菌污染的状况并评价消除污染的措施及其效果。方法：于198年5月4日－7月1日对流行区A、B、C河流按每隔300－500米设立取水点，每2－3天采样1次；1998年7月－2001年12月对13个曾反复阳性点按月进行霍乱弧菌监测。采取对下水道污水消毒，拆除沿江两岸厕所和人群查源等措施以消除污染。结果：1998年4月28日－6月1日在流行区29个取水点检出霍乱弧菌。毒力测定人源株以中等毒力为主（68．8％），而水源株以弱毒为主（66．7％）。1998年7月至2001年12月采水796份，均未检出霍乱弧菌，24份水样L型菌，非可培养状态也为阴性。结论：该流行区江河段遭受一时性霍乱弧菌污染，1998年6月2日以后已彻底消除，未发生水型传播疫情，1998年8月－2001年12月，该区域也未再有霍乱病例发生，表明消除措施效果显著，也证明当地霍乱疫情系输入性。

Study on monitoring and elimination of V. cholerae O1 contamination in aquatic systems in cholera endemic areas

Objectives To understand fully the status of V. cholerae O1 contamination in aquatic systems of endemic areas and to assess the eliminating strategies and their effectiveness. Methods In the period May 4 to July 1, 1998, rivers A,B,C in epidemic areas were monitored for V. cholerae O1 contamination by collecting water samples on a basis of every 2-3 days from the sampling sites established every a distance of 300_500 meters.From June 1998 through December 2001, a monthly surveillance was conducted in 13 settings where pathogens were persistent. Measures were taken to curb the contamination situation, including disinfecting sewage, demolishing toilets along riversides, and screening patients. Results V.cholerae O1 strains were found in 29 sampling sites during April 28_June 1,1998. The cholera toxin assay showed that a majority of human isolates (68.8%) were moderately toxigenic strains ,while those from water sources(66.7%) were mainly mildly toxigenic.Among 796 water samples obtained from July 1998 to December 2001,no V. cholerae O1 and L_type V.cholerae were observed,and nor were nonculturable organisms.Conclusions The waters in the epidemic areas were ever seriously contaminated with V. cholerae O1. The situation has been practically eradicated and no water_borne infections have occurred since June 2, 1998. The evidence of no case reports during the period August 1998 to December 2001 demonstrated the elimination strategies were highly effective. Also, it was confirmed that cholera epidemic was caused by imported infections.