Abstract: Objective To observe the impact on the transmission of schistosomiasis in areas where the local inhabitants migrated from outside embankment to new settlements. Methods Two villages (Chenqiao and Qingjie) where the inhabitants had moved out and another 2 villages (Jiangzhou and Xiaohuang) disused for both inhabitants and cultivated land were selected for the investigation. Data on prevalence in human and domestic animals, and Oncomelania snail habitats, were collected. Results After moving from outside embankment to new settlements, the density of infested snails in Chenqiao and Qingjie decreased by 79.1% and 45.2% in 2005 compared with that in 2002, and the infection rate of snails decreased by 75.5% and 84.9%, respectively(P＜0.01). In Jiangzhou and Xiaohuang, the density of infested snails decreased by 100% and 74. 9% in 2005 compared with that in 2002, and the infection rate of snails decreased by 100% and 40.0%, respectively (P＞0.05). In villages that only disused for inhabitants, the density and egg-positive rate of feces collected from the wild were higher than the other 2 villages. However, in villages disused for both inhabitants and cultivated land, the density and egg-positive rate of wild feces decreased gradually and no egg-positive feces was found in 2005. The prevalence of schistosomiasis in humans in villages disused only for inhabitants changed slightly from 2002 to 2005, but decreased gradually in villages disused for both inhabitants and cultivated land. Higher prevalence in cattle was found in villages disused only for inhabitants. Number of cattle reduced yearly and no cattle left in villages disused for both inhabitants and cultivated land in 2005. Conclusion No significant change on the factors of schistosomiasis transmission has been found in villages disused only for inhabitants, but the transmission has been effectively controlled in villages disused for both inhabitants and cultivated land.

Key words: Migration to new settlement, Schistosomiasis, Transmission