Schistosome (Schistosoma mansoni) fluke worms mating, illustration. During mating, the male worm wraps his body around the female, enclosing her in a gynaecophoric canal that runs down his body. S. mansoni is a parasitic trematode worm that causes schistosomiasis, the second most prevalent tropical disease in the world after malaria. The worm larvae enter the body through via infested water. They then mature in the intestines before laying eggs around the body. A female schistosome can produce up to 300 eggs per day. Symptoms of schistosomiasis include fever, chills, and blood in the urine and stools.