[Contrastive analysis of environmental factors between Oncomelania hupensis snail marshland and snail natural death marshland in eastern Dongting Lake schistosomiasis endemic areas].

OBJECTIVE:To study the reasons of natural death of Oncomelania hupensis snails in marshland by comparing the differences of environmental factors between snail marshland and non-snail marshland in East Dongting Lake schistosomiasis endemic areas. METHODS:Two adjoining marshlands were selected, one was a snail marshland and another was a non-snail marshland. The measuring points were set by grid of "20 m x 20 m". The soil moisture, elevation, soil pH and temperature of the points were measured, and the snails of the points were surveyed. RESULTS:The elevation, soil pH and temperature of the snail natural death marshland were all lower than those of the snail marshland (P < 0.01). The soil moisture, elevation, soil pH and temperature of different snail densities in the snail marshland were different (P < 0.05). The soil moisture of the non-snail group was higher than that of other four groups (P < 0.01) and the soil moisture of the group with 0-11 snails per frame was lower than that of other four groups (P < 0.01). The elevation of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame and the group with more than 39 snails per frame (P < 0.05). The soil pH of the group without snails was higher than that of other four groups (P < 0.01) and the soil temperature of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame. The differences of soil moisture and elevation of different death snail densities were not significant, while the differences of soil pH and temperature were significant. The soil pH of the non-snail died group was higher than that of the 2-died, 3-died and more than 3-died groups (P < 0.05). The soil temperature of the non-snail died group was higher than that of other four groups (P < 0.05). CONCLUSION:The elevation, soil pH and soil temperature within the range of the research may be the factors affecting the snail natural death and the soil moisture, elevation, soil pH and soil temperature may be the factors affecting the distribution of snails.