Abstract:

Objective  To analyze the impact of water transfer project from the Yangtze River to the Huaihe River on the transmission of schistisomiasis in the Chaohu Lake area, and evaluate the transmission risk in the potential endemic area. Methods In 2012, 1 fixed and 3 mobile surveillance sites in the Chaohu Lake area were selected, and the local people, mobile population and livestock were investigated by immunological assays and/or stool examinations. The distribution of Oncomelania snails was surveyed in risk areas and suspicious areas, and the snail spreading pattern was conducted through salvaging floaters in rivers connected with the Yangtze River. Results A total of 314 local residents were detected by indirect hemagglutination assay(IHA), but there were no positives. A total of 302 mobile population were examined by IHA, and the positive rate of antibody was 1.32%（4/302）；30 individuals were examined by stool tests, and the positive rate was 20%(6/30). A total of 60 livestock were examined by stool hatching method, but none tested positive. A total of 53.73 hm² were surveyed in 16 risk areas and suspicious areas, but there were no Oncomelania snails. A total of 49kg floaters were catched, but no Oncomelania snails were found, while 40 other snails were found adhering the floaters. Conclusion Oncomelania snails have not been found in the Chaohu Lake area until now, while schistosomiasis cases had been found in the mobile population, which indicated that long term surveillance scheme on schistosomiasis should be established in the area.

Key words: Chaohu Lake area, Schistosomiasis japonica, Potential endemic area, Transmission risk, Evaluation