Dipylidium caninum belongs to which group of parasites?

• A. Cestodes
• B. Trematodes
• C. Nematodes
• D. Acanthocephalids

Answer: (A)

Dipylidium caninum is a tapeworm, so it belongs to the cestodes. Cestodes are flat, segmented worms that live in the intestine and attach with a scolex, followed by a chain of sections called proglottids. They lack a true digestive system and absorb nutrients through their body surface. Dipylidium’s life cycle also involves an intermediate host (fleas or lice), which is typical for many cestodes. By contrast, trematodes are leaf-shaped flukes usually with complex life cycles involving mollusks, nematodes are elongated roundworms with a full digestive tract, and acanthocephalids have a distinctive retractable, spiny proboscis. So the correct grouping is cestodes.