Which intestinal parasite infection can cause vitamin B12 deficiency?

Which intestinal parasite infection can cause vitamin B12 deficiency?

• A. Diphyllobothrium latum
• B. Taenia saginata
• C. Hymenolepis diminuta
• D. Echinococcus granulosus

Answer: (A)

Vitamin B12 absorption happens in the terminal ileum and depends on intrinsic factor. Diphyllobothrium latum, the fish tapeworm, lives in the small intestine and efficiently takes up vitamin B12 from the host lumen. Over time this reduces the B12 available for absorption, leading to megaloblastic anemia and sometimes neuropathy. The other parasites listed do not typically cause B12 deficiency: Taenia saginata (beef tapeworm) usually causes little to no B12 loss; Hymenolepis diminuta infections are rare in humans and not associated with B12 depletion; Echinococcus granulosus forms hydatid cysts rather than affecting B12 absorption. So the fish tapeworm is the parasite linked to B12 deficiency.

Vitamin B12 absorption happens in the terminal ileum and depends on intrinsic factor. Diphyllobothrium latum, the fish tapeworm, lives in the small intestine and efficiently takes up vitamin B12 from the host lumen. Over time this reduces the B12 available for absorption, leading to megaloblastic anemia and sometimes neuropathy. The other parasites listed do not typically cause B12 deficiency: Taenia saginata (beef tapeworm) usually causes little to no B12 loss; Hymenolepis diminuta infections are rare in humans and not associated with B12 depletion; Echinococcus granulosus forms hydatid cysts rather than affecting B12 absorption. So the fish tapeworm is the parasite linked to B12 deficiency.