Abstract:Objective To determine the impact of the project of building dike for storing water against schistosomiasis transmission,and provide the practical basis of snail and schistosomiasis elimination for the huge project “Poyang Lake Control Project” which probably be built in future.Methods To collect the data of water level during the period from April to September since 1995,and analyze the relationship between the water level changes and snail breeding at the inside of the dike;to survey the historical endemic situation of schistosomiasis including snail population in the storing water area after building dike;to investigate the snail density in marshland and the infection rate of human being and livestock at the inside of the dike to confirm the present endemic situation of schistosomiasis in Saicheng Lake region.Results Snails were found in the marshland with 14~18m elevation around Saicheng Lake region.After building dike,the wave's scope of water level at the inside of dike decrease significantly:the lowest water level was 2m± higher than that at out of dike and the highest water level was 0.5~1.5m lower than that at the outside of dike.under the condition of the water level mentioned above,the period of snail was eliminated was calculated to be 5 years.the infection rate of human being and livestock reduced remarkably following the decrease of snail area and snail density year by year,and no snail and no cases of schistosomiasis has be found in this survey.Conclusion Schistosomiasis transmission can be interrupted by snail elimination after building dike for storing water.