Schistosomiasis is an infectious disease caused by parasitic trematodes of the genus <i>Schistosoma</i> that colonize human blood vessels and release eggs that can cause granulomatous reactions leading to acute (swimmer's itch or acute schistosomiasis syndrome) or chronic disease. Depending on where the eggs lodge, manifestations of chronic schistosomiasis can include diarrhea, abdominal pain, loss of appetite, anemia (intestines), hepatosplenism, periportal fibrosis with portal hypertension (liver), urogenital inflammation and scarring, hematuria and dysuria (genitourinary system). Other patients may be asymptomatic.

Thrombosis of the portal vein and/or its tributaries, which include the splenic vein and the sup-erior and inferior mesenteric veins.