Tapeworm Infection in Cats

What are tapeworms?

Tapeworms are intestinal parasites of the cat and dog. They are classified as cestodes. They belong to a different family than hookworms and roundworms, which are the other common intestinal parasites of dogs and cats. Several types of tapeworms are known to infect cats. Dipylidium caninum is by far the most common species observed in cats.

The tapeworm uses its hook-like mouthparts for anchoring to the wall of the small intestine. Eventually, adult tapeworms may reach several inches in length. As the adult matures, individual segments called proglottids break off from the main body of the tapeworm and pass into the cat's feces.

Are certain cats more likely to get Dipylidium caninum tapeworms?

"Fleas are the intermediate host for Dipylidium caninum."

Fleas are the intermediate host for Dipylidium caninum. In other words, the tapeworm is unable to complete its life cycle without the presence of fleas in the environment. Regardless of whether the owner may have seen fleas, the cat must have ingested a flea in order to have tapeworms. Consequently, tapeworms are more common in environments that are heavily infested with fleas. Lice are also reported as intermediate hosts for this tapeworm but they are relatively uncommon parasites of cats.

How do cats get Dipylidium caninum tapeworms?

First, tapeworm eggs must be ingested by flea larvae, an immature stage of the flea. Contact between flea larvae and tapeworm eggs are facilitated by contaminated bedding or carpet. Adult fleas do not participate in this part of the tapeworm lifecycle. The infected flea larvae will mature into adult fleas.

Next, the cat chews or licks its skin in response to a fleabite, and inadvertently swallows the flea. As the flea is digested within the cat's intestine, the tapeworm is released and it hatches and anchors itself to the intestinal lining.

What are the clinical signs of tapeworm infection?

Tapeworms are not particularly harmful to the cat and few clinical signs are attributed to their presence.

"...owner's aversion to the presence of the crawling proglottids or tapeworm segments."

Usually, the cat is brought to the veterinarian because of the owner's aversion to the presence of the crawling proglottids or tapeworm segments. Rarely, tapeworms may cause debilitation or weight loss if they are present in large numbers. 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 in length.

How are tapeworms diagnosed?

Most commonly, owners recognize that the cat has tapeworms and bring this to the attention of the veterinarian. When terminal segments of the tapeworm break off and pass into the cat's stool, they can be seen crawling on the surface of the feces. These proglottid segments look like grains of cooked white rice or cucumber seeds. Less commonly, segments are seen moving around the cat's anus. Each of these proglottid capsules contains up to twenty tapeworm eggs.

When these proglottids are released into the environment, they dehydrate and harden, becoming smaller and taking on a golden hue. Eventually, they break open and release their contents. You should note that tapeworms are not readily diagnosed with routine fecal examinations. Because of this, you should notify your veterinarian when tapeworm segments are found in your cat's stool.

What is the treatment for tapeworms?

A variety of products are available to treat tapeworms in cats but they are not all equally effective. For the best advice on the type of de-worming preparation most suitable for your cat, you should seek the help of your veterinarian. The most effective worming products are only available by prescription from a licensed veterinarian.

The deworming medication called an anthelmintic may be given as a tablet or an injection. After treatment, the tapeworm dies and is usually digested within the intestine, so worm segments don't usually pass into the stool. Side effects, such as vomiting and diarrhea, are rarely reported with the newer tapeworm medications.

"Flea control is the cornerstone of preventing Dipylidium caninum infection."

Flea control is the cornerstone of preventing Dipylidium caninum infection. Flea control products are becoming more effective and convenient to use. Depending on the type of product you use and the presence of other pets in your home, you may also need to treat your house and yard for fleas. With some of the newer products, environmental control of fleas may not be needed. Circumstances vary, however, so be sure to talk to your veterinarian.

If the cat lives in a flea-infested environment, tapeworm infection can become re-established within a few weeks. This is very rarely due to treatment failure; in most cases, reappearance of tapeworm segments represents re-infection of the cat. Additional recommendations include:

1.  Promptly have your cat treated when tapeworms are detected.

2.  Remove and dispose of all pet feces properly, especially in public parks, yards, or playgrounds.

3.  Teach and practicestrict hygiene practices for children after playing outdoors.

What is the prognosis?

New tapeworm medications and flea preventives are safe and effective. The prognosis for successful treatment is excellent. In most cases, prevention is successfully accomplished by using a monthly flea preventive.

Are Dipylidium caninum tapeworms from my cat dangerous to my family or me?

Humans can become infected with tapeworms, although infection is rare because it is requires ingestion of a flea. Most reported cases have involved children living in less-than-ideal conditions. The risk for human infection with Dipylidium caninum is quite remote but does exist.

What are the other tapeworms that can infect my cat?

The other common tapeworms that can infect a cat are members of a group called Taenia. The intermediate hosts of these tapeworms are mice, birds, or rabbits.

"...cats acquire Taenia infestations by eating infected mice, birds, or rabbits."

In a similar manner to Dipylidium transmission, cats acquire Taenia infestations by eating infected mice, birds, or rabbits. Tapeworm medications are highly effective at eliminating these parasites. However, if your cat continues to eats prey, re-infection can occur with passage of tapeworm segments in 6-8 weeks. 

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 readily seen. Trappers and hunters in the north central United States and south central Canada may be at increased risk for infection with this worm when strict hygiene is not practiced. Foxes, coyotes, and the wild rodents upon which they prey are important in the life cycle of this parasite. Dogs and cats may also become infected if they eat rodents carrying the parasite. When eggs of Echinococcus are passed in the feces of the dog and cat, humans are at risk for infection. Free-roaming cats and dogs may need to be periodically treated with tapeworm medication. Rodent control and good hygiene are important in preventing the spread of this disease to humans. As with the more common tapeworm, 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 seen associated with cats are due to tapeworms. Children who contract pinworms do not get them from cats or dogs.