Hymenolepis nana differs from all other human tapeworms because of which unique feature of its life cycle?

• A Its larvae migrate through the lung during development
• B It requires two intermediate hosts, a copepod and a freshwater fish
• C Humans acquire infection only by ingesting cysticerci in pork
• D It can complete its entire life cycle in the human intestine without any intermediate host, allowing internal autoinfection ✓

Explanation

Hymenolepis nana, the dwarf tapeworm, is the smallest cestode infecting humans and the only one that can complete its life cycle in a single host. Eggs released from gravid proglottids can hatch directly in the small intestine, and the resulting cysticercoid develops into an adult worm without leaving the host, causing internal autoinfection and heavy worm burdens, especially in children. No intermediate host is obligatory, although beetles can serve as optional vectors.

Reference: Paniker's Textbook of Medical Parasitology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.