Experimental studies on the life cycle of Cyclocoelum mutabile (Zeder) (Trematoda: Cyclocoelidae).

Abstract

Miracidia of Cyclocoelum mutabile (Zeder), each containing a single redia, were infective to six species of snails: Helisoma trivolvis (Carpenter), Gyralus circumstriatus (Tyron), Promenetus exacuous (Say), Armiger crista (L.), Physa gyrina (Say), and Lymnaea elodes (Say). The miracidia partially penetrated the epithelial tissues of the snail and the rediae migrated into the snail tissues within an hour after attachment. Rediae were first observed in their final position on the dorsal surface of the head foot 1 week after exposure. Cercariae encyst as metacercariae in the tissues of the same snail between 2 and 3 weeks after exposure. Metacercariae were infective to coots, Fulica americana (Gm.), and mature worms were recovered from the air sacs 30 days after exposure.