Which parasite is known to cause Cobalamin (B12) deficiency?

Diphyllobothrium latum, commonly known as the fish tapeworm, is known to cause cobalamin (vitamin B12) deficiency. This organism can inhabit the intestines of humans who consume undercooked or raw fish containing its larvae. Once ingested, Diphyllobothrium latum can grow quite large in the host's intestine and has a unique ability to absorb significant amounts of vitamin B12, which can lead to a deficiency in the host.

Vitamin B12 is crucial for the synthesis of DNA, the formation of red blood cells, and the functioning of the nervous system. When the fish tapeworm absorbs this vitamin in substantial quantities, it competes with the host's intake, resulting in a reduced availability of vitamin B12 in the body. This can eventually lead to megaloblastic anemia and neurological issues, symptoms often associated with Vitamin B12 deficiency.

In contrast, the other parasites mentioned do not cause B12 deficiency in the same manner. Ascaris lumbricoides and Fasciola hepatica do not have the same mechanism of B12 absorption as Diphyllobothrium latum. Furthermore, Giardia lamblia primarily causes gastrointestinal symptoms and malabsorption but is not