Common Intestinal Parasitic Worms in Cats

By Tess Thompson

Of the numerous intestinal parasites, roundworms and tapeworms are the most frequent feline parasites that infect cats. The commonalities between these two intestinal parasites end here. Roundworms are round and slimy creatures, whereas tapeworms are flat and segmented.

Both the worms shed eggs that are passed out in the feces of the cat. But roundworms and tapeworms look different. Roundworm eggs excreted in feces are microscopic, whereas tapeworm eggs are released as packets from the end segments that detach from the worm. These segments can be seen in the cat’s feces or clinging to the hair near the anus of the cat.


The two common species of roundworms found in cats are:

  • Toxocara cati
  • Toxascaris leonina

Eggs from both the species are generally eaten by a cat when they are still in their non-infectious stage. They may also be ingested by an intermediate host, like a mouse or a rat.

Toxocara cati differs from the other roundworm in one feature. It has the capacity to remain dormant in female cats. A queen may harbor larvae from previous infections that remain encysted in various tissues in the body. At the time of pregnancy, these larvae migrate to the mammary glands. Larvae transmit through the milk. That the litter of an infected mother will be infected as well is a foregone conclusion.


Like roundworms, there are two species of tapeworms that usually infest cats.

  • Dipylidium caninum
  • Taenia taeniaformis

Both infest cats in different ways. Excreted tapeworm segments containing eggs of Dipylidium caninum are consumed by fleas. A flea-infested cat ingests the infected fleas while grooming and gets infected in the process. It can be presumed that a flea-infested cat, a common occurrence, will almost definitely have a tapeworm infestation in some time.

On the contrary, eggs of Taenia taeniaformis species are eaten up by intermediate hosts. Cats get infected only after eating small rodents like mice and rats that have eaten tapeworm segments. Taenia taeniaformis is less common, and only outdoor cats and those involved in hunting get infected with it.

Symptoms of worms in dogs and cats are very similar. Diarrhea and vomiting is a common symptom. Like dog tapeworms, tapeworms in cats also cause irritation at the anal site where they are commonly seen. Cats that excessively lick the anal area or drag their posteriors can be suspected to have tapeworm infection.

However, it is the physical sighting of worms in dogs and cats that is conclusive evidence of their infestation. Sometimes a microscopic examination is required. Commonly known as fecal flotation, a solution is added to the feces that cause the eggs to float on the surface. Such tests help in establishing prevalence of parasites other than tapeworms and roundworms.


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