Which parasite is classically treated with praziquantel and lays eggs in mesenteric vessels?

Which parasite is classically treated with praziquantel and lays eggs in mesenteric vessels?

• A. Enterobius vermicularis
• B. Taenia solium
• C. Schistosoma mansoni
• D. Ascaris lumbricoides

Answer: (C)

Praziquantel is the drug of choice for trematodes and cestodes, and Schistosoma mansoni is a blood fluke that lives in the mesenteric veins of the large intestine. It lays eggs right in those veins, and many of the eggs migrate to the intestinal lumen to be shed in stool, while others get trapped in tissues like the liver, causing granulomatous inflammation and potential portal hypertension over time. The eggs of S. mansoni have a distinctive large lateral spine, helping distinguish it from other schistosome species. This combination of praziquantel responsiveness and eggs deposited in mesenteric vessels is characteristic of S. mansoni. In contrast, Enterobius vermicularis lays eggs around the anus, Taenia solium eggs or proglottids are shed in feces, and Ascaris lumbricoides eggs are also shed in feces but do not involve mesenteric venous egg deposition.

Praziquantel is the drug of choice for trematodes and cestodes, and Schistosoma mansoni is a blood fluke that lives in the mesenteric veins of the large intestine. It lays eggs right in those veins, and many of the eggs migrate to the intestinal lumen to be shed in stool, while others get trapped in tissues like the liver, causing granulomatous inflammation and potential portal hypertension over time. The eggs of S. mansoni have a distinctive large lateral spine, helping distinguish it from other schistosome species. This combination of praziquantel responsiveness and eggs deposited in mesenteric vessels is characteristic of S. mansoni. In contrast, Enterobius vermicularis lays eggs around the anus, Taenia solium eggs or proglottids are shed in feces, and Ascaris lumbricoides eggs are also shed in feces but do not involve mesenteric venous egg deposition.