血吸虫病传播阻断地区钉螺复现状况调查分析

目的了解广东、广西、福建、上海和浙江5省(市、自治区)血吸虫病传播阻断标准(以下简称"达标")地区的钉螺复现状况,以掌握最新螺情动态变化,为针对性制订防治对策提供科学依据。方法2006～2007年对5省市近3年内钉螺复现地区开展调查并汇集历史螺情相关资料。采用系统抽样法结合环境抽样法查螺并对钉螺复现原因进行分析。结果近3年内,广东无复现螺点。调查广西、福建、上海和浙江18个复现螺点及浙江1个新发现螺点。螺点主要分布于山丘地带的复杂孳生环境,复现时间为3～35年,有螺面积均小于原历史钉螺分布面积,无感染性钉螺和当地感染的病人及病牛。各螺点复现前大多选用五氯酚钠喷洒灭螺。结论山丘地带复杂环境和单纯性灭螺方法、查螺质量问题以及"达标"后预防性灭螺措施实施欠佳是复现螺情逐年回升的重要因素。

Analysis of re-emergence of Oncomelania hupensis in area where schistosomiasis transmission-interrupted in China

Objective To understand the re-emergence of Oncomelania hupensis in five provinces(autonomous regions or municipalities),i.e.Guangdong,Guangxi,Fujian,Shanghai,Zhejiang,where schistosomiasis transmission had been interrupted,and reveal the dynamic patterns of the snails in order to provide the basic information for schistosomiasis control.Methods From 2006 to 2007,we investigated the status of O.hupensis distribution in some foci where the snails re-emerged in the latest 3 years and collected the corresponding historical data.The systematic and environmental sampling survey was undertaken in the investigation of the snail distribution,and the re-emergence of O.hupensis was analyzed.Results In the past 3 years,no re-emergences were happened in the foci in Guangdong,however,18 foci were found re-emerged in Guangxi,Fujian,Shanghai and Zhejiang.A new focus was found in Zhengjiang province.The majority of these foci located in mountainous regions with complex environment.The re-emergence intervals were from 3 to 35 years.The acreage of snail distribution in all re-emerge foci was lower than corresponding historical status.No infected O.hupensis,patients or sick cattle were detected in the foci.Elimination of the snail had been performed using sodium pentachlorophenate in most of the foci according to historical data.Conclusion The re-emergence of O.hupensis in the specific areas where schistosomiasis has been interrupted were attributed to several factors,such as the complexity of snail habit environment,the low quality of annual snail survey and unitary method of elimination,and low efficiency of preventive snail elimination after reaching criteria of the transmission interruption.