Dipylidium caninum uses which type of host during its lifecycle?

• A. Flea larvae
• B. Mice
• C. Humans
• D. Dogs themselves

Answer: (A)

Dipylidium caninum is a tapeworm that must pass through an intermediate host to complete its development. The cysticercoid stage develops inside a flea, specifically within the flea larvae that inhabit the environment and feed on organic debris. When a dog or cat ingests an infected flea during grooming, the cysticercoid is released in the intestine and develops into the adult tapeworm there. Humans can become accidental hosts if they swallow an infected flea, but the lifecycle relies on the flea as the essential intermediate host, not mice or the dog itself as an intermediate. Controlling fleas therefore directly helps prevent Dipylidium infections.