Survey of Water-Snail in National Schistosomiasis Surveillance Areas in Sichuan Province,2005-2009

Objective To learn about the current status of schistosomiasis epidemic in Sichuan province,provide scientific evidence for the development or revise of schistosomiasis prevention and control measures and the evaluation of control effort.Methods Water-snail survey was conducted in the areas where Oncomelania was found or might be found by systematic sampling and environmental sampling.Results The area with water-snail declined from 351 853 m2 in 2005 to 142 983 m2 in 2009,the water-snail density declined from 0.7 per 0.11m2 to 0.33% per 0.11m2 and the water-snail infection rate declined from 0.06% to 0%.Since 2007,no infected water-snail had been found.Most water-snails were found in ditches.Conclusion The indicators of the survey showed that the water-snails density and infection rate in all surveillance sites was lower in 2009 than in 2005.It is necessary to strengthen the surveillance and maintain prevention and control effort to prevent the re-emergency of schistosomiasis transmission in Sichuan province.