It's a little dense, but this page details the life cycle and you can see how intricate it is. Not to say elegant, in its way.


For a portal to an exhaustive discussion of schistosomes, here is http://www.path.cam.ac.uk/~schisto/intro.html.

To extract:

...Infection occurs through contact with fresh water that contains infective cercariae released from an intermediate host snail. The cercaria penetrates intact human skin and transforms into the...larva, that migrates through the bloodstream to the [liver] to complete the parasite's lifecycle...

Penetration of the skin by the cercaria...may result in a form of dermatitis, cercarial dermatitis ["swimmers' itch"], though this is not as important in terms of pathology as egg-induced pathology, (see below)...

Male and female worms differentiate, pair and migrate into the small [veins] draining the intestine (S. mansoni, S. japonicum) or the bladder (S. haematobium). In these sites, and fully exposed to the host immune system, adult worms live for 3 to 8 years, although cases have been reported of individuals still excreting parasite eggs 30 years after leaving a schistosome endemic area...

Eggs pass into the lumen of the intestine or bladder and, if deposited in fresh water, hatch to release ciliated miracidia that infect the snail... However, many eggs also lodge in the definitive host's liver and intestine or bladder, where they cause the pathology associated with schistosomiasis...

Google is a wonderful tool. This (and much more) came out of "schistosome larvae"