Fleas on your pet are more than an itchy annoyance. Fleas are also a vector for many conditions, including infestation with tapeworms.
The tapeworm that infects cats and dogs, Dipylidium caninum, is a member of a large group of parasitic flatworms called cestodes. There are over a thousand different species of cestodes. D. caninum, the species that infects cats and dogs, attaches to the intestinal wall using a retractable rostellum, which is a muscular structure armed with hooks. The worm also has teeth that it uses to grab onto the intestinal wall. The tapeworm is segmented. A fully mature adult tapeworm consists of the head segment, a neck segment, and multiple tail segments. By the time the tail segments drop off, they are mostly just an egg sac.
The sac is passed out through the host’s digestive tract. The segments look like small grains of rice and are able to move. Segments that have dried up look like sesame seeds. When the sac breaks, the eggs inside are released.
The good news is that you or your other pets cannot get tapes from the segments being passed by your infected pet. The egg must develop further before it can infect a mammal.
Here is where the flea becomes a factor.
In pets with flea infestations, the larval fleas hatching in the area consume organic debris, flea dirt (digested blood shed by adult fleas–it looks like pepper) and any tapeworm eggs. The tapeworm egg proceeds to develop inside the flea and by the time the flea is an adult, the tapeworm can infect mammals. When a cat or a dog swallows the infected flea, something that is very easy to do during regular grooming, the cat or dog becomes the new host. The flea body is digested, the tapeworm is released and it finds a spot to attach and continues the lifecycle.
While the segments that hold the eggs are small, an adult tapeworm can be six inches long or more.
Most pets infected with tapeworms show no signs of illness. Tapeworms require very little nutrition to thrive, and healthy dogs and cats don’t suffer from tapeworm infection. Most owners only know their pet has the parasite when segments appear in the stool or in the fur.
It is possible, although highly unlikely, for humans to become infected with D. caninum, via the same method as cats and dogs, swallowing an infected flea.
Tapeworm infection can be treated with oral, injectable or topical drugs. The adult worms are killed and digested and do not pass out with the stool.
Although tapeworm infections are not generally serious, they should still be treated. Owners should also consider tapeworm infections as evidence of current or prior flea infestation and take appropriate steps to remove and prevent fleas.