Diphyllobothriidea is an order of

Cestoda Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of ...

(tapeworms). Members of this order are gut

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

of vertebrates. They infect mammals as their definitive hosts and use either copepods (a group of small crustaceans found in the sea and nearly every freshwater habitat, e.g. ''

Spirometra ''Spirometra'' is a genus of pseudophyllid cestodes that reproduce in canines and felines, but can also cause pathology in humans if infected. As an adult, this tapeworm lives in the small intestine of its definitive host and produces eggs th ...

'') or both copepods and fish as in the broadfish tapeworm as intermediate hosts.

References

Cestoda Platyhelminthes orders {{Cestoda-stub