<unk>  is a significant parasite of humans. Of the trematodes,<unk> s are atypical in that the adult stages have two sexes (dioecious) and are located in blood vessels of the definitive host. Most other trematodes are hermaphroditic and are found in the intestinal tract, or organs such as the liver. The lifecycle of<unk> s includes two hosts: a definitive host (i.e. man) where the parasite undergoes sexual reproduction, and a single intermediate snail host where there are a number of asexual reproductive stages.
Schistoma<unk>  is one of the major agents of<unk> asis and is named after Sir Patrick<unk> who first identified it.
Schistosoma mansoni
Trichuris trichiura
Trypanosoma cruzi
Ascaris lumbricoides
Entamoeba histolytica
Trichinella spiralis
Ancylostoma duodenale
Onchocerca volvulus