Primarily, tapeworms come from fleas.

Since fleas are the intermediate host of Dipylidium caninum, the most common species of tapeworm, pet owners should be on the lookout for flea infestations.

Dipylidium caninum, as an adult tapeworm, attaches to the walls of the small intestine. As the tapeworm matures, the egg-engorged segments — proglottids — break off. Thus begins a new life cycle.

As the proglottids are passed by the pet and rupture, egg packets are released into all areas of the pet’s environment. Flea larvae, which also are present, eat the individual tapeworm eggs. These eggs hatch and larvae grow within the flea. When fleas mature into adults, they jump onto their pet hosts for a blood meal. During normal grooming, the host pet ingests all or parts of fleas, and the tapeworm larvae present are released and mature in the pet’s small intestine.