Observations on Vectors of Schistosomiasis mansoni Kept out of Water in the Laboratory. II

Abstract

Australorbis glabratus and Tropicorbis centimetralis were kept out of water in the laboratory under simulated field conditions by using large wooden boxes filled with soil. The snails were put on wet mud, or in shallow water over mud, and allowed to dry gradually. The snails were out of water after the first day and the soil rapidly attained a very low water content. Under these conditions the snails lived out of water for many months and some lived more than one year. The snails did not respond to disappearance of the water by entering the mud but some were capable of penetrating several cm into very soft, wet mud. Snails buried in relatively dry soil lived about as long as those at the surface. Snails buried in water-saturated mud died rapidly. Accidental burial of snails under field conditions may favor survival under some conditions.