The Post-Embryonic Developmental Stages of Cestodes

Abstract

This chapter discusses the post-embryonic developmental stages of cestodes. Life cycles and larval growth in the orders tetraphyllidea, pseudophyllidea, and cyclophyllidea is discussed. The chapter discusses the histology, histochemistry and fine structure of lecanicephalidea, pseudophyllidea, and cyclophyllidea. It also deals with host-parasite relationships in invertebrate hosts, vertebrate intermediate hosts, and final hosts with consideration of immunity. Finally, the chapter deals respectively with metabolism and growth in vitro, followed by conclusions drawn. In vitro studies on growth and development reaffirm the contention that different species of cestodes may have very different requirements in axenic environments and also that these requirements may change at different stages of growth of one and the same species. Some of the areas requiring much additional study are (a) life histories of lesser known cestode groups, with careful description of pre-adult stages so that this information could form the “backbone” of a more rational systematic grouping, (b) studies on the biochemical behavior of apparently related species, and comparison of the behavior of any one species in different in vitro environments, (c) additional data on environmental tolerances of a species at different stages of development, and (d) frequencies of mutations in laboratory strains, and experimental work on the induction of mutations by means other than X-irradiation.