RESUMO
Objective To evaluate the comprehensive benefit about the installation obstructed snails in large irrigation canals for preventing snails spreading in lake-swamp areas of schistosomiasis.Methods The installation obstructed snails was set up in upper reaches of main canal Shilong, Tianmen City Data of snails and schistosomiasis prevalance were collected and analysed. The comprehesive benefit was analysed with the cost-benefit methods of economic hygienics. Results After the installation obstructed snails was set up the snails areas and human infection rate decreased markedly. New patients with acute and advanced schistosomiasis were not found in the irrigation areas. The ratio of comprehesive cost-benefit was 1∶9.84,the ratio of net benefit was 8.84∶1. Conclusion Setting up the installation obstracted snails to cut off the way of snails spreading was the effective measure of control schistosomiasis in lake-swamp areas.