Cysticercosis in humans results from ingestion of eggs of which tapeworm?

• A. Taenia solium
• B. Taenia saginata
• C. Echinococcus granulosus
• D. Diphyllobothrium latum

Answer: (A)

Cysticercosis happens when a person ingests the eggs of Taenia solium. Those eggs release larvae (oncospheres) that penetrate the intestinal wall and travel through the bloodstream to tissues such as muscle, eye, or brain, where they develop into cysticerci. This tissue form is what causes disease, especially neurocysticercosis when the brain is involved. In contrast, taeniasis—the intestinal tapeworm infection—occurs when people eat undercooked pork containing cysticerci, leading to an adult worm living in the gut rather than tissue cysts. The other organisms listed do not cause cysticercosis: Taenia saginata is the beef tapeworm and typically produces taeniasis; Echinococcus granulosus causes hydatid disease; Diphyllobothrium latum causes a fish tapeworm infection.