Dermatitis - parasitology, Lung - microbiology, Skin - microbiology, Dermatitis - immunology, Humans, Schistosoma, Schistosomiasis - complications, Cercaria - immunology, Schistosomiasis - diagnosis, Animals, Swimming, Schistosomiasis - immunology, Skin - pathology, Central Nervous System - microbiology, Dermatitis - diagnosis, Disease Models, Animal