Cordicephalus Wardle, McLeod & Stewart, 1947 Diphyllobothrium is a genus of tapeworms which can cause diphyllobothriasis in humans through consumption of raw or undercooked fish.

[1] Other members of the genus Diphyllobothrium include D. dendriticum (the salmon tapeworm), which has a much larger range (the whole northern hemisphere), D. pacificum, D. cordatum, D. ursi, D. lanceolatum, D. dalliae, and D. yonagoensis, all of which infect humans only infrequently.

[3] The adult worm is composed of three fairly distinct morphological segments: the scolex (head), the neck, and the lower body.

[5] Adult tapeworms may infect humans, canids, felines, bears, pinnipeds, and mustelids, though the accuracy of the records for some of the nonhuman species is disputed.

[6] Because humans do not generally eat undercooked minnows and similar small freshwater fish, these do not represent an important source of infection.

One or several of the tape-like proglottid segments (hence the name tapeworm) regularly detach from the main body of the worm and release immature eggs in freshwater to start the cycle over again.

It can also cause structural changes in the GI tract as it modulates neuroendocrine responses and enhances secretion and gut motility.

[11][12] The worm absorbs around 80% of dietary B12 and prolonged infection can also cause abdominal pain, mechanical obstruction, and symptoms of iron deficiency anemia.