infectious diseases
Schistosomiasis
Key Points
Schistosomais the only trematode that invades through the skin; over 230 million people are infected worldwide. When cercariae penetrate the skin, they lose their forked tail and become schistosomula, which travel through the bloodstream to the liver, where they mature; as adults, they migrate to their ultimate home in the intestinal veins or the venous plexus of the genitourinary tract. Ova in the liver trigger a granulomatous reaction that can lead to fibrosis and portal hypertension, resulting in splenomegaly, esophageal varices, and hematemesis. Organisms in the intestine can cause bloody diarrhea, and organisms in the bladder can cause hematuria and chronic cystitis. Treat withpraziquantel. To prevent infection, avoid contact with fresh water in endemic areas. 