Tapeworms in Cats

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 Life cycle of the cat tapeworm | Life cycle of the dog tapeworm | Life cycle of the broad tapeworm | Can people get tapeworms from cats? | Do tapeworms harm cats? | How to be sure a cat has tapeworms? | Treating cats for tapeworms | Preventing cats from becoming infected

There are three tapeworms commonly found in the intestines of cats in Alberta. The life habit of each cat will determine the kind of tapeworm it acquires.

Taenia taeniaeformis is the most common tapeworm found. Cats become infected with this parasite by eating mice or other small rodents. The dog tapeworm, Dipylidium caninum, is the second most common tapeworm found. Cats become infected with it by eating fleas or lice that carry the larvael stages of this tapeworm. The least common tapeworm is the broad tapeworm, Diphyllobothrium latum. Cats acquire this parasite by eating raw fish. An understanding of the life histories of tapeworms helps to control these parasites.

The life history of a tapeworm consists of three stages: the adult, egg and larvae. The significance of each stage is described below for the three common tapeworms of cats.

Life Cycle of the Cat Tapeworm

An adult T. taeniaeformis is approximately 60 cm long and lives in the small intestine of the cat. The posterior segments of the tapeworm produce eggs that accumulate until the segment becomes packed full. These gravid segments detach from the end of the tapeworm and pass in the feces.
The detached segments are capable of movement and may crawl out of the anus onto the perianal skin. The eggs contaminate the food of rats, mice and rabbits. The egg must develop further in one of these animals to complete the life cycle of the tapeworm.
The egg hatches in the intestine of the rodent, and the enclosed larvae migrates to the liver and develops into a fluid filled larvae called a cysticercus. When infected rodents are eaten by cats, the tapeworm larvae is released and develops into an adult tapeworm in the intestine of the cat. It may live there for up to two years if no treatment is given.

Life Cycle of the Dog Tapeworm

The life cycle of the dog tapeworm consists of three stages similar to those of the cat tapeworm. However, the eggs of the dog tapeworm are passed in the feces and eaten by the larvae of fleas or biting lice.
The parasitic larvae is released from the egg and develops into a solid-body form (cysticercoid) in the flea or louse. Cats become accidentally infected by eating infected fleas or lice. The dog tapeworm requires two to three weeks to develop into a segment-shedding tapeworm in the cat. The fully grown tapeworm may reach 30 cm in length.

Life Cycle of the Broad Tapeworm

In contrast to the "cat" and "dog" tapeworms, the broad tapeworm releases eggs directly from the segments into the intestine of cats, which are then passed in the feces. Many segments release their eggs until the end segments become empty. These empty segments detach in long chains instead of individually, as do the segments of the dog and cat tapeworms. Eggs of the broad tapeworm must then develop in water for several weeks before becoming infective.
Diphyllobothrium requires at least two intermediate hosts: the first is a copepod (small crustaceans related to crabs, shrimp, etc.) and the second, a fish. The larvae released from the egg develops into a solid, worm-like larvae in the copepod. When the infected copepod is eaten by a fish, the larvael tapeworm is released, and it migrates to the muscle of the fish (e.g. Pike) and develops further. The larvae matures into an adult tapeworm when the cat eats the infected fish. These parasites may be 3 to 10 m long.

Can People get Tapeworms from Cats?

The tapeworms described here may be acquired by accidentally swallowing an infected flea (dog tapeworm) or eating a piece of uncooked infected fish (broad tapeworm).

Do Tapeworms Harm Cats?

With few exceptions, these well-adapted parasites cause little harm or inconvenience to their cat host. However, the sight of their segments crawling about the fur or on recently passed feces of a pet is not appealing.

Clinical signs may not always occur, but when present, they may include unthriftiness, depression, irritability, an unpredictable appetite, poor coat condition, colic and mild diarrhea. A heavy infestation may causse anemia or weight loss.

How to be Sure a Cat has Tapeworms?

Correct diagnosis of the common feline tapeworm parasites is essential. The segmens from each tapeworm have characteristic shapes that help identify the adult parasite present in the cat. The eggs are generally not reliable for specific identification.

A general diagnosis is made by microscopic examination of cat feces for tapeworm eggs. Examining segments found in the feces or on the cat around the anal area, or on the hair in the anal area, will aid identification. See a veterinarian for a diagnosis.

Treating Cats for Tapeworms

There are several drugs used to treat tapeworm infections including praziquantel, bunamidine, niclosamiden and mebendazole.

There are some precautions that must be observed when you administer drugs to animals. Contact a veterinarian for the appropriate drug and the method of treatment.

Preventing Cats From Becoming Infected

Cat owners can reduce the chances of their pet becoming infected by the following:
  • cooking or freezing fish before feeding it to cats
  • preventing cats from hunting small rodents
  • keeping cats free of fleas and lice.
If you find tapeworm segments, take them to a veterinarian for identification. The veterinarian will provide you with the proper drug and advice needed to rid your cat of tapeworms.

Prepared by:
Dr. Murray Kennedy - Food Safety Division

Source: Agdex 655-5. Revised April 2001.
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For more information about the content of this document, contact Daniel Fitzgerald.
This document is maintained by Jennifer Rutter.
This information published to the web on April 1, 2001.