Which Schistosoma species is present in the Americas?

• A. Schistosoma haematobium
• B. Schistosoma mansoni
• C. Schistosoma japonicum
• D. Schistosoma mekongi

Answer: (B)

In the Americas, humans are infected by Schistosoma mansoni. This species is transmitted by Biomphalaria snails and lives in the mesenteric veins of the large intestine, with eggs causing intestinal disease. Its geographic distribution includes the Caribbean and parts of South America, notably Brazil, making it the one typically found there.

The other species have different regional patterns: Schistosoma haematobium mainly causes urinary schistosomiasis in Africa and the Middle East; Schistosoma japonicum is found in East Asia and the Philippines; Schistosoma mekongi is from the Mekong region. Historically, Schistosoma mansoni was introduced to the Americas and established endemic cycles with native snail hosts.