The Life Cycle of Crassiphiala bulboglossa (Trematoda: Strigeida). Development of the Metacercaria and Cyst, and Effect on the Fish Hosts

Abstract

The life cycle of Crassiphiala bulboglossa was completed by exptl. infecting the snail, Helisoma anceps, with miracidia hatched from ova obtained from adult C. bulboglossa from the kingfisher, Ceryle alcyon, and subsequently infecting fish, Pimephales p. promelas and Fundulus diaphanus menona with the resulting cercariae. The miracidium and cercaria are described; both are very similar to those of the apparent closest relative, Uvulifer ambloplitis. The progressive development of the metacercaria is described. The larvae locate in the skin and the strigeid characteristics appear at 14 days, reserve excretory system at 19 days, and cyst of parasite origin at 21-22 days. The host cyst appears at 6 days, begins to accumulate pigment cells in its outer layers at ca. 7 days, and becomes a typical black-spot fibrous cyst at ca. 20 days. Large numbers of cercariae killed fish but not until 10-15 days post infection. No evidence of immunity was observed.