Diffusion and distribution of imported Oncomelania snails in non-endemic areas of schistosomiasis / 中国血吸虫病防治杂志

ABSTRACT

Objecitve To observe the diffusion and distribution of imported Oncomdania snails in non-endemic areas of schistosomiasis.so as to provide scientific basis for developing the scheme of snail surveillance.Methods Oncomelania snails from the msrshland of Dongting Lake were imported in a waste land in March,2008,Qingxin County,which belonged to non-endemic areas of schistosomiasis.and their diffusion and distribution condition were observed from May to December in the same year.Resuits A total of 1 600 Oncomelania snails were imported.The occurrence rate of frame with snails in sunny days and cloudy rainy days were22.88%and 29.24%,respectively,and there was a statistically significant difference between them(χ~2=4.113,P=0.043).Those in waste Land and the sides/bottoms of the ditches were 9.38%and 35.99%,respectively,and the difference between them also showed a statistical significance(χ~2=67.246,P<0.001).The average density of living snails in sunny days and cloudy rainy days were 0.79 and 1.11 No./0.1 m~2,respectively,and those in waste land and the sides/bottoms of the ditches were0.11 and 1.34 No./0.1 m~2.The furthest diffusion distance of snailswas 4.5 m.Conclusions The detective opportunity of imported snails is relatively high in cloudy rainy days,which mainly distribute at the sides/bottoms of ditches and diffuse along the ditches.