What are tapeworms?
Tapeworms are flat, segmented, intestinal parasites of the cat and dog. They belong to a different class (Cestoda) than other intestinal parasites, such as hookworms and roundworms. Several types of tapeworms infect pets, but the most common species in cats is Dipylidium caninum.
The tapeworm uses its hook-like mouthparts to anchor itself to the wall of the small intestine. Eventually, adult tapeworms reach lengths of up to 11 inches (30 cm).
As the adult tapeworm matures, individual segments (proglottids) break off from the main body of the tapeworm and pass in the cat’s feces. The segments look like grains of rice or cucumber seeds and are about ½-inch (12 mm) long and about ⅛-inch (3 mm) wide.
Occasionally, proglottids can be seen moving on the hairs around the anus, or more commonly, on the surface of freshly passed feces. As a proglottid dries, it becomes a golden color and eventually breaks open, releasing the fertilized eggs into the environment. A proglottid may contain as many as 20 tapeworm eggs.
How do cats get tapeworms?
First, the cat inadvertently ingests a flea carrying tapeworm larvae. As the cat digests the flea, the tapeworm egg is released into the intestines, hatches, and then anchors itself to the intestinal lining. The tapeworm matures and produces eggs (in segments) that are excreted with the cat’s feces. Fleas ingest the eggs and then jump onto the cat, where the cat ingests them, and the life cycle begins again.
Cats cannot become infected by eating tapeworm eggs. Tapeworms must first pass through the flea (the intermediate host) before they can infect the cat.
What are the clinical signs of tapeworm infection?
Usually, an infected cat’s owner will notice the presence of proglottids crawling on its feces. A cat will occasionally scoot or drag its anus across the ground or carpet due to the anal irritation caused by the proglottids; however, this behavior is much more common in dogs than cats.
Occasionally, a tapeworm will release its attachment in the intestines and migrate to the stomach. When this happens, the cat may vomit an adult tapeworm several inches long. Rarely, tapeworms may cause debilitation or weight loss if they are present in large numbers.
How are tapeworms diagnosed?
Most commonly, an owner recognizes that their cat has tapeworms when they observe proglottids on feces or in vomit and brings this to the attention of the veterinarian. When segments of the tapeworm break off and pass into the cat’s stool, they can be seen crawling on the surface of the feces. Less commonly, segments are seen moving around the cat's anus. Tapeworms are not readily diagnosed with routine fecal examinations.
How are tapeworms treated?
A deworming medication (parasiticide) may be given as a tablet, topical treatment, or injection. It causes the parasite to be digested in the intestines, so you normally will not see tapeworms passed in the stool. These drugs are very safe and should not cause any side effects. A variety of products are available to treat tapeworms in cats, but they are not all equally effective. The most effective deworming products are only available by prescription from a licensed veterinarian.
"Flea control is critical for managing and preventing tapeworm infection."
Flea control is critical for managing and preventing tapeworm infection. Flea control products are convenient to use. Depending on the type of product and the presence of other pets in your home, you may also need to treat your house and yard for fleas. If your cat lives in a flea-infested environment, reinfection with tapeworms may occur in as little as two weeks. Tapeworm medication is very effective, so recurrent tapeworm infections are almost always due to reinfection from fleas. Your veterinarian can recommend safe and effective flea control for your pet.
What is the prognosis?
The prognosis for successful treatment is excellent.
Can I get tapeworms from my cat?
Humans can become infected with Dipylidium caninum tapeworms, but infection is rare, because it requires ingestion of a flea. A few cases of tapeworm infection have been reported in children. Vigorous flea control will help eliminate any risk of children becoming infected.
Taenia is another common type of tapeworm that can infect cats. These tapeworms use mice, birds, and rabbits as intermediate hosts. Cats acquire Taenia infestations by eating an infected host. Tapeworm medications are highly effective at eliminating these parasites. However, if your cat continues to hunt and eat prey, they can be reinfected and pass tapeworm segments in six to eight weeks. In cats that hunt frequently, regular deworming is recommended.
Another, less common group of tapeworms called Echinococcus is of increasing concern as a threat to human health. These tapeworms cause serious, potentially fatal disease when humans become infected.
Infection with this parasite is harder to diagnose than Dipylidium because the segments are small and not easy to see. Trappers and hunters in the north-central United States and south-central Canada may be at increased risk of infection with this worm when strict hygiene is not practiced. Foxes, coyotes, and wild rodents are important in this parasite’s life cycle.
Cats may also become infected with Echinococcus if they eat rodents carrying the parasite, although cats are less commonly infected than dogs. When Echinococcus eggs are passed in the cat’s feces, humans are at risk of infection by inadvertent ingestion of the eggs. In humans, the disease is called hydatidosis, hydatid disease, or hydatid cyst disease, and it causes cysts to form in the liver.
Free-roaming cats may need to be periodically treated with deworming medication. Rodent control and good hygiene are important in preventing the spread of this disease to humans. As with the more common tapeworm, Dipylidium, human infection with Echinococcus is rare, yet possible.
My child has pinworms. Did they come from my cat?
Tapeworms and pinworms look very similar. However, contrary to popular belief, pinworms do not infect cats or dogs. Any worm segments associated with cats are due to tapeworms. Children who contract pinworms do not get them from cats or dogs.
