Review Question - QID 101172

Echinococcus granulosus is the most common cause of hydatid cysts in the liver.

Echinococcus granulosus is a tapeworm (Cestode) transmitted by dogs (definitive host) and sheep (intermediate host). Eggs are ingested (most commonly from dog feces), hatch in the intestine, and the larvae disseminate throughout the body. The larvae then form hydatid cysts in organs, including bone, muscle, lungs, and especially the liver. Notably, rupture of these cysts during surgery can result in anaphylaxis upon the patient's exposure to the antigen. Treatment is surgery along with -bendazoles.

Incorrect Answers:
Answer 1: Diphyllobothrium latum is the fish tapeworm that can grow to 45m in length. It does not cause hydatid cysts but it does cause b12 deficiency.
Answer 3: Taenia solium is the pork tapeworm that can encyst in the brain, causing neurocysticercosis ("swiss cheese" lesions).
Answer 4: Schistosoma infection can result in the deposition of eggs in the venous walls of the liver, causing portal hypertension. However, schistosoma is not associated with the formation of hydatid cysts.
Answer 5: Clonorchis sinensis is transmitted in undercooked fish and causes inflammation of the biliary tract.