Viral, Protozoan, and Helminthic Diseases of the Cardiovascular and Lymphatic Systems

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…from the snail in a form called cercaria. These can then penetrate the skin of a swimming or wading human. Then, the microbes are carried by the bloodstream to either the liver or urinary bladder. The cercaria matures into adult form, and a male and female produce ova. The ova can cause tissue damage called granulomas. Adult worms are unaffected by the human immune system. Schistosomiasis occurs in Asia, Africa, South America, and the Caribbean.