Trematodes

Abstract

This chapter focuses on members of the clade Digenea of the phylum Platyhelminthes. At least 70 species of digenean trematodes have been recorded as adult parasites in humans. These species are endoparasitic, occupying a variety of tissue sites. Members of the genus Schistosoma are blood flukes responsible for the important human disease schistosomiasis. The second strategy, evident in the remainder of the human‐infecting species, is foodborne transmission, and parasites that use this strategy can be termed collectively the foodborne digeneans. For these species, the human‐infective stage, a metacercaria, is ingested with food. The impact of these foodborne trematodes on human health is large. The primary epidemiological features governing human infection include the distribution of suitable snail intermediate hosts, human food consumption behaviors, the presence of suitable zoonotic hosts, and the potential for water contamination with human or animal excreta.