The Location of the Schistosome Vectors, Australorbis glabratus and Tropicorbis centimetralis, on and in the Soil on Dry Natural Habitats

Abstract

The snails are known to survive the dry season in n.-e.- Brazil on habitats that are dry for 5 to 7 months each year. To learn where the snails are located during this period, 15 meter-square quadrants were searched for snails by systematically removing the debris and successive soil levels up to 6 cm taken. Fifty-nine percent of the living snails were at the surface and 34% were in the top cm of soil. Only 1% were more than 2 cm deep. Thus, the living snails were at or close to the surface and there was no evidence of deep soil penetration. As the dry season progressed the number of living snails was gradually reduced. Snails buried in the soil did not appear to survive longer than those at the surface.