Echinostomes: systematics and life cycles

This chapter provides a review of the most significant literature in the last decade on the systematics and biology of echinostomes and echinostome-like digeneans. This review is primarily concerned with members of the genus Echinostoma, although members of other genera (Echinoparyphium, Echinochasmus, Himasthla, Hypoderaeum, Petasiger, Euparyphium, Stephanoprora, Isthmiophora, and Acanthoparyphium) and echinostome-related genera (Parorchis, Philophthalmus and Ribeiroia) are also considered. The literature on molecular systematics and morphometrics of these trematodes is reviewed. Specific mention is made of the life cycle patterns of echinostome and echinostome-like digeneans along with an overview of recent advances on different topics in the biology of these trematodes; the review covers various aspects of the different stages of these organisms, i.e., free-living stages (miracidia and cercariae), and parasitic stages in the invertebrate hosts (sporocysts, rediae, and metacercariae) and vertebrate hosts (adults).