Experimental Infection of the Snail Australorbis glabratus with the Trematode Schistosoma mansoni and the Production of Cercariae

Abstract

Exposure to 1 miracidium per snail leads to infection of 8% of snails; exposure to 5-7 mira-cidia yields infection in 50-60% of the snails. Half of a given population of miracidia died in about 8 hours. Snails infected by exposure to 5-7 miracidia liberate on the avg. 700 cercariae per snail per day when stimulated under the conditions descr. After 2 days of rest from stimulation, this avg. is 1200. Illumination of snails in addition to warming increases the avg. emergence by 30-90 %. The cercaria-producing half-life of snails infected by exposure to 5-7 miracidia and stimulated to liberate cercariae 4 or 5 times a week is 4 weeks. Half of populations of cercariae in suspensions of 150 per ml. spring water, incubated at 30[degree]C, are dead between 8 and 16 hours after emergence from the snails. In Tyrode solutions containing 0.1 % glucose, half such cercariae populations are dead in 20 hours.