COMPARISON OF THE MIGRATIONS OF FASCIOLA-HEPATICA SPOROCYSTS IN LYMNAEA-TRUNCATULA AND OTHER RELATED SNAIL FAMILIES

The migration and definitive localization of sporocysts in the snail b ody were studied in four species (Aplexa hypnorum, Lymnaea glabra, L. truncatula, Physa acuta), each of which was exposed to a single miraci dium and killed during a period ranging from the 1st to the 5th day po stexposure. When penetration occurred through the mantle, tunnels were found mainly in the mantle or kidney in Lymnaea adults and also exten ded to the foot in many physidid adults and in newborns of the four sp ecies. The sporocysts preferentially localized in the zone surrounding the kidney and heart beginning on the 4th day in Lymnaea spp. and dis appeared in Aplexa and Physa snails on the 3rd day. When penetration o ccurred through the foot or the tentacles, tunnels were found in the f oot and extended inconstantly to the mantle according to the snail spe cies involved. Sporocysts were encountered in the foot as well as the mantle or the zone surrounding the kidney and heart. The significance of these results is discussed in relation to the snail host and the en try site used by the Fasciola hepatica miracidium.