Which organism is commonly associated with flea-borne tapeworm infections in dogs?

• A. Dipylidium caninum
• B. Taenia pisiformis
• C. Echinococcus granulosus
• D. Diphyllobothrium latum

Answer: (A)

Flea-borne tapeworm infections in dogs occur when a dog swallows an infected flea, which serves as the intermediate host. The organism commonly responsible is Dipylidium caninum. In its life cycle, the cysticercoid stage develops inside the flea. When the dog grooms or chews and ingests the flea, the parasite matures into an adult tapeworm in the small intestine. The dog then sheds tapeworm segments (proglottids) in the feces or around the perianal region. These segments resemble tiny grains of rice or cucumber seeds and can be seen on fur or in the environment, contributing to transmission as fleas pick up the eggs and continue the cycle. Control of fleas is essential to break this cycle and prevent reinfection, and treatment typically involves antiparasitic medication effective against tapeworms.

Taenia pisiformis infects dogs through ingestion of an intermediate host like rabbits, not fleas. Echinococcus granulosus involves dogs as definitive hosts and hydatid disease in intermediate hosts, not flea-borne transmission. Diphyllobothrium latum is a fish tapeworm requiring fish as an intermediate host, not fleas.