The isolation of viable schistosome eggs by a digestion technique

A method is described of isolating viable eggs of Schistosoma mansoni from the liver and gut of infected hamsters by digesting away the unwanted tissue with trypsin and pepsin. The final washing by centrifugation is regulated so that most of the dead eggs are removed in the supernatant. Using this method, at least 100,000 eggs can be obtained from five hamsters. About one-third of the eggs are mature and show active flame cell movement; they hatch readily in fresh water and the miracidia have been successfully used to infect snails. Eggs prepared in this way are suitable for use in the circumoval precipitin test.