Which tapeworm causes hydatid disease with cysts in the liver and is transmitted via dog feces?

Which tapeworm causes hydatid disease with cysts in the liver and is transmitted via dog feces?

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

Answer: (C)

Hydatid disease is caused by Echinococcus granulosus, a tapeworm whose life cycle involves dogs as the definitive host and livestock as intermediate hosts. Humans become accidental hosts by ingesting tapeworm eggs shed in dog feces; inside the human, the larvae migrate to the liver (the most common site) and form fluid-filled hydatid cysts that can grow and may rupture, potentially triggering an allergic reaction or spreading. This presentation—liver cysts from a dog-associated tapeworm—is characteristic of Echinococcus granulosus. In contrast, Taenia solium and Taenia saginata cause intestinal tapeworm infections from undercooked pork or beef, and Taenia solium can lead to cysticercosis in tissues but not hydatid liver cysts. Diphyllobothrium latum is the fish tapeworm acquired from raw fish and does not produce hydatid cysts.

Hydatid disease is caused by Echinococcus granulosus, a tapeworm whose life cycle involves dogs as the definitive host and livestock as intermediate hosts. Humans become accidental hosts by ingesting tapeworm eggs shed in dog feces; inside the human, the larvae migrate to the liver (the most common site) and form fluid-filled hydatid cysts that can grow and may rupture, potentially triggering an allergic reaction or spreading. This presentation—liver cysts from a dog-associated tapeworm—is characteristic of Echinococcus granulosus. In contrast, Taenia solium and Taenia saginata cause intestinal tapeworm infections from undercooked pork or beef, and Taenia solium can lead to cysticercosis in tissues but not hydatid liver cysts. Diphyllobothrium latum is the fish tapeworm acquired from raw fish and does not produce hydatid cysts.