Chapter 3. Recent advances in the biology of echinostomes.

This chapter examines the significant literature on the biology of echinostomes. The members of the family Echinostomatidae are medically and veterinary-important parasitic flatworms that invade humans, domestic animals and wildlife and also parasitize in their larval stages numerous invertebrate and cold-blooded vertebrate hosts. All echinostomes possess a complicated lifecycle expressed by: (i) alternation of seven generations known as the adult, egg, miracidium, sporocyst, redia, cercaria and metacercaria, and (ii) inclusion of three host categories known as the definitive host and first and second intermediate hosts. Moreover, echinostomes have served as experimental models in parasitology at all levels of organization. We discuss recent advances in several areas of the biological sciences that feature studies on echinostomes. Initially, we consider aspects of the lifecycle, development and systematics of selected members of the Echinostomatidae. We then highlight host-parasite interactions between echinostomes and their intermediate and definitive hosts with emphasis on the application of novel techniques to these topics.