[Effect evaluation of water conservancy project with ditches managed against Oncomelania hupensis in Yunnan Province].

OBJECTIVE:To evaluate the effect of hydraulic schistosomiasis control project with ditches managed on Oncomelania hupensis snail control. METHODS:From 2009 to 2011, the snail investigations and schistosomiasis surveillance were carried out in Dali City and Yongsheng County, two sites of national schistosomiasis surveillance. The history data of schistosomiasis control were collected and analyzed. RESULTS:At the harden sections of the water conservancy project with ditches managed in Shajing Village of Dali City, only one snail was found in 2010 with the density of living snails of 0.004 snails/0.1 m2, while the densities of living snails were respectively 0.080, 0.002 snails/0.1 m2 and 0.007 snails/0.1 m2 in unhardened sections of the project from 2009 to 2011. No snails were found in the harden sections of the water conservancy project with ditches managed in Gaojiacun Village of Yongsheng County, while the densities of living snails were respectively 0.040, 0.030 snails/0.1 m2 and 0.040 snails/0.1 m2 in unhardened sections of the project from 2009 to 2011. After the ditches were hardened, no infected snails were found from 2009 to 2011, and the appearance rate of frames with snails and density of living snails were both decreased, while they were both higher in unhardened ditches. CONCLUSIONS:The hydraulic schistosomiasis control project has obvious effect on control snails, but the maintain work should be strengthened after the project is completed.