三峡建坝后长江江苏段水位变化对血吸虫病流行影响的研究 Ⅰ.江苏段江滩滩情和病情资料及建坝前后江水水位资料的收集与分析

为研究三峡建坝后长江中下游水位变化对江苏江滩钉螺分布与血吸虫病传播的影响，通过对长江江苏段６５５块沿江历史有螺滩近年滩情、螺情和病情资料及建坝前后水位变化预测资料的收集与分析，推算出江苏省受建坝后水位变化影响的江滩为６０７４．６０９８万ｍ２，占江滩总面积的３５．８０％；２～４月份水位升高，有２５７４．０２３１万ｍ２滩块提前受淹，其中包括１１０．３８８５万ｍ２有螺滩；１０～１１月份水位降低，使得３５００．５８６９万ｍ２滩块提前退水，其中包括５４８．７４０８万ｍ２有螺滩和９１．７７９２万ｍ２阳性钉螺滩。

IMPACT OF VARIATION IN WATER LEVEL OF THE YANGTZE RIVERAFTER THE CONSTRUCTION OF THE THREE GORGE DAM ONTHE TRANSMISSION OF SCHISTOSOMIASIS IN JIANGSU,CHINA* .COLLECTION AND ANALYSIS OF DATA ON LANDS, SNAILS AND CASES FROMTHE MARSHLANDS ALONG THE YAN

In order to probe the impact of the variation in water levels of the Yangtze River after the Construction of the Three Gorge Dam on the distribution of snails and transmission of schistosomiasis on marshlands in Jiangsu, the current data on lands, snails and cases in 655 areas of marshlands along the Yangtze River in Jiangsu Province were collected and analysed. Variations in local water levels before and after buiding the Three Gorge Dam were predicted based on hydrographical data provided by the Yangtze River Irrigation Committee. It has been found that in Jiangsu Province about 60 746 098 m2 of marshland will be altered in hydrographical situation due to the variation in water level of the Yangtze River after the Dam building. In these altered marshlands about 25 740 231 m2 of areas, including 1 103 885 m2 of areas with snails will be submerged ahead because of water level rising during February-April, and about 35 005 869 m2 of areas, including 5 487 408 m2 of areas with snails and 917792 m2 of areas with infected snails will come out ahead because of water level dropping during October-November.