Abstract:

Objective To evaluate the effect of the intervention measures for schistosomiasis control adapted to the ecological environment changes in Jiang Han plain caused by the establishment of the Three Gorges Dam. Methods Four villages in Qianjiang City were selected to implement paddy-upland rotation, crawfish-paddy alternation, water control and soil improvement, and adjusting agricultural structure to rebuild the waterlogging low yielding land and to change the snail habitat environment respectively. The snail habitat area, mean density of living snails and prevalence of schistosomi-asis in human and cattle were compared with those of the control villages. Miracidia hatching methods were used to examine the prevalence in human and cattle. Results In the four experimental villages, the snail-ridden area decreased by 100%, 51.35%, 62.16% and 87.88% respectively; mean density of living snails decreased by 100%, 69.41%, 52.30% and 75.77%, with a t value of 9.37, 4.91, 2.31 and 9.16, I′<0.01. Human prevalence of schistosomiasis in 2005 in village with crawfish-paddy alteration decreased significantly than control （x²=39.84，I′<0.01）; decreased by 73.10% in village with water control and soil improvement in 1990 than in 1987 （x²=236.10，P<0.01）. Conclusion Implementation of the four intervention measures reaches a remarkable benefit in reforming snail habitat and protecting environment, which can be recommended to the inner embankment type endemic regions.

Key words: Three Gorges Dam, Underground water level, Schistosomiasis, Environmental change, Snail control