The correct answer is D, Schistosoma mansoni.  Infection with Schistosoma mansoni is acquired when cercariae in water penetrate the skin.  Cercaria are released in the water after development in the intermediate mollusk host and humans become infected during swimming, bathing, or other activities that involve water contact.

Click here to open a new window with a schematic diagram showing the life cycle of Schistosoma sp.  Close the new window to return to this page.