worm treatment for cats

Common Intestinal Parasites in Cats

Did your cat just vomit up a long white worm? Are you seeing rice-like segments in your cat’s stool? Is your cat losing weight even though it’s eating well? Does your cat have fleas? Any and all of these can indicate that your cat has intestinal parasites. Keep reading to learn about these parasites and what you can do to protect your cat.

This article was written by a FirstVet vet

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What are parasites?

Parasites are organisms that can live on the inside or the outside of your cat, as well as dogs, people, and essentially most animals on the planet. The three main categories of parasites are protozoa, helminths, and ectoparasites.

  • Protozoa are microscopic organisms that consist of only one cell.
  • Helminths are worms that can be flat, round, or thorny-headed.
  • Ecto means outside, as in ‘outside the body’, so examples of ectoparasites are fleas, mites, lice, and ticks.
  • Another group of parasites called trematodes or flukes can also infect cats.

How does my cat get worms?

The tendency for cats to become infected with specific parasites is directly related to the area of the country in which they live, if they are indoors or outdoors, whether they live with other animals, whether or not they are on parasite prevention, and of course, if they’ve seen a vet for testing and/or treatment.

Although intestinal parasites can affect cats of any age, it’s quite common for kittens to have parasites from birth. They can get these from their mother’s placenta and/or milk. Your vet should check your kitten’s stool sample for parasites at their first visit, as well as the subsequent 2-3 visits (every 3-4 weeks) when receiving their initial vaccines.

The stool is looked at under the microscope to check for roundworm eggs (Toxocara cati or less commonly Toxascaris leonina), tapeworm eggs (Dipylidium caninum), or protozoa (Giardia). Your kitten will likely also be ‘dewormed’ (given an oral liquid dewormer) at each of these visits. Parasites have different life cycles and aren’t always ‘shedding’, so they may not always be noted on your cat’s fecal exam even when present. Your kitten should start monthly heartworm/flea/tick prevention as soon as they are old enough (different medications are approved for varying ages, but typically start around 6-8 weeks of age).

If your cat is an outdoor cat, they’re more likely to get intestinal parasites from the soil or other animal’s feces, contaminated water, eating birds and mice, interaction with other animals, and exposure to ectoparasites such as fleas which can carry tapeworms. However, even indoor cats can have parasites. This can occur if your cat was never initially tested or treated for parasites as a kitten and has been building up a large worm burden without your knowledge.

What types of intestinal worms are common in cats?

In cats, the most common intestinal parasites are roundworms and tapeworms of the helminth category. We can also see the protozoa Giardia. If your cat defecates or vomits a long thin white worm, this may be a roundworm (less likely a hookworm, Ancylysoma spp or whipworm, Trichuris trichiura, though it is possible). If you see small white segments that look like rice on their behind, these are tapeworm segments. Giardia often causes diarrhea, but you cannot see it without a microscope, and even then, it can be challenging to find.

In parts of the world where Salmon are common (Southwestern US but also sometimes Northwestern US, Canada, and Siberia), cats may become infected with the “Salmon Poisoning Fluke”, Nanophyetus salmincola. This is a flat parasite that carries a bacteria which causes the cat to develop gastroenteritis. Cats that eat frogs, reptiles, or rodents may become infected with a different type of fluke, Alaria, found in North and South America, Europe, Australia, and Japan.

How do I know if my cat has worms?

When you bring your cat to the vet, it’s helpful if you can bring a stool sample and even the worm(s) with you for identification purposes. Some cats don’t show any signs until they’re stressed in some way, or you may notice diarrhea or vomiting but not see any parasites. If your cat is losing weight but still eating well, parasites could be the cause (among other diseases). Parasites can build up in such large quantities that they can actually obstruct the intestinal tract. Some cats can become extremely dehydrated from vomiting and diarrhea. Do not let this go on without a vet exam and intervention.

Deworming Cats

There are several types of commonly used dewormers in veterinary medicine, depending on the type of parasite. There are oral, injectable, and topical treatments as well as preventions. It’s important to know what type of parasites your cat has before treating. Do not ever assume that just because your cat was ‘dewormed by the vet’ one time a year ago that they cannot possibly have any parasites. Even indoor cats who never go outside and don’t live with other animals can get parasites.

For example, you go to your friend’s house who has a dog that has fleas, you bring home a flea, and that flea immediately hones in on your cat as being a much more desirable host than you. This flea also happens to be carrying tapeworm, and suddenly a few weeks down the line, your cat is pooping out little white segments.

Can I get worms from my cat?

Please always keep in mind that people can get tapeworms and Giardia (though Giardia tends to be species-specific), so always wash your hands after handling your pets or their stool if you suspect that they are infected. Roundworm eggs that are accidentally consumed can migrate to various organs and cause damage (visceral larval migrans). Hookworm larvae can penetrate the skin and cause cutaneous larval migrans. Please remember to be conscious of anyone in the home who has a decreased immune system, including the very young and the elderly. We all know that kids do things like pet the cat and then stick their hands in their mouths!

What should I do if my cat has worms?

Ask your vet about the different options for your cat’s monthly parasite prevention. Because this is a hot topic in the veterinary field, there are constantly new products coming out. It is not advised that you purchase over-the-counter parasite control products unless your vet specifies a certain product. Some of these have been found to cause negative side effects, seizures, and even death. It is also very important that you never use a flea medication that is meant for dogs on your cat - this can also lead to severe side effects such as seizures and death.

Read more:

How to Apply “Spot On” Medication to Your Dog or Cat

Summer Dangers for Cats

Heartworm Disease in Dogs and Cats

Have more questions about common intestinal worms in cats?

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This article was written by a FirstVet vet

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