|This article does not cite any references or sources. (August 2014)|
Dipylidium caninum, also called the flea tapeworm, double-pore tapeworm, or cucumber tapeworm (in reference to the shape of its cucumber-seed-like proglottids), though these also resemble grains of rice or sesame seeds), is a cyclophyllid cestode that infects organisms afflicted with fleas and canine chewing lice, including dogs, cats, and sometimes human pet-owners, especially children. The adult worm is about 18 inches (46 cm) long. Gravid proglottids containing the worm's microscopic eggs are either passed in the definitive host's feces or may leave their host spontaneously and are then ingested by microscopic flea larvae (the intermediate hosts) in the surrounding environment. These larvae eventually pupate and transform into adult fleas still carrying the tape worm, which are then ingested by a dog or cat during grooming activity. From there, the worm enters the animal's digestive tract and anchors itself to the intestinal wall where it will soon begin generating proglottids, completing the life cycle. Examples of fleas that can spread D. caninum include Ctenocephalides canis and Ctenocephalides felis.
As in all members of family Dipylidiidae, proglottids of the adult worm have genital pores on both sides (hence the name double-pore tapeworm). Each side has a set of male and female reproductive organs. The uterus is paired with 16 to 20 radial branches each. The scolex has a retractable rostellum with four rows of hooks, along with the four suckers that all cyclophyllid cestodes have.
In children, infection causes diarrhea and restlessness. As with most tapeworm infections, the drugs of choice are niclosamide or praziquantel. The best way to prevent human infection is to treat infected animals to kill fleas. Tapeworm infection usually does not cause pathology in the dog or cat, and most pets show no adverse reaction to infection other than increased appetite.
The other tapeworm infecting cats is Taenia taeniaeformis, though this form is much less commonly encountered that the one currently under discussion here.