Cercariae of Digenetic Trematodes: Use In Laboratory Investigations

 

Ronald Rosen

Tested Studies in Laboratory Teaching, 2001, Volume 22

Abstract

In the complex life cycle of a digenetic trematode, the cercaria larva is shed from a snail intermediate host and represents a short-lived, aquatic transfer stage to the next host. Due to its temporary free-living existence, the cercarial stage is ideal for a number of investigative projects. Two general experiments will be conducted with the unusually large cercaria of Proterometra macrostoma. Students assess the effect of: (1) different light wavelengths on the vertical swimming burst distance of this type of cercaria and (2) pH and pepsin on the emergence of the P. macrostoma distome (pre-adult) from its cercarial tail. The latter study represents an in vitro simulation of what naturally occurs in the stomach of the centrarchid fish definitive host.

Keywords:  parasites, cercaria, trematode, Digenea, Proterometra, fish parasites

Clemson University (2000)