Worms in Cats: How to Identify, Treat, and Prevent Them (Vet-Approved) (2024)

Worms in cats can cause significant health issues. Understanding the symptoms of worms in cats, types, and treatments for these parasites is crucial for your pet’s health.

“Worms” — this is actually a common misnomer for gastrointestinal (GI) parasites. That’s because all GI worms are parasites but not all GI parasites are worms.

There are truly only 6 GI parasites common in cats, the first 4 of which are, well, worms.

For comprehensive information on worms in dogs, including hookworms, refer to our detailed article on hookworms in dogs.

These worms occur in dogs (Toxocara canis) and cats (Toxocara cati) and are super-obvious spaghetti-looking worms that are highly visible to the naked eye. They are also called ascarids.

Your pet might vomit up a big pile of them or pass a pocketful of them in poop. To top off the yuck factor, they are often moving!

Puppies and kittens routinely get these worms from their mothers. Adult dogs and cats get them from infected feces. And dogs can certainly get them from eating poop.

Rarely, roundworms can infect people. Kids are more at risk because they might be playing in sand or soil with infected fecal matter.

Roundworm infections in people can be very serious. The worm can migrate to the eyes, lungs and other organs. Washing hands and cleaning up all pet excrement safeguards against this rare zoonotic disease.

Tapeworms (Dipylidium caninum) are little flat worms that you can see in poop, but they’re not as disgusting as roundworms, in my opinion.

To use yet another food analogy, they look like rice — or, for the more discerning palate, orzo.

A tapeworm is a long, flat, off-white worm, but they are segmented. Often, you find only pieces of a tapeworm that look like rice grains in feces or taking up real estate around your pet’s anus, dried up on the fur.

Once in a while, you get to see a long, living tapeworm doing its slinky dance and pulsating out in little segments.

Tapeworms are generally contracted when your dog or cat eats a flea while grooming. The tapeworm eggs are inside the flea but can’t come to full maturity until eaten by a mammal.

Hookworms (Ancylostoma caninum) are very small parasites that infect the small intestine of dogs and sometimes cats.

They attach to the lining of the gut and suck blood, causing mild to severe GI signs.

These parasites also migrate through the lung, but coughing is fairly rare. The majority of damage is typically done in the intestines.

Dogs and cats contract hooks from infected feces in soil.

Hookworms live in the soil and can infect humans by entering the skin, causing a parasitic skin disease called cutaneous larva migrans. This is most common in warmer climates, where people walk on infected soil or beaches with bare feet.

Giardia is a type of protozoan parasite that attaches to cells in the small intestines of many species (dogs, cats and humans), which leads to maldigestion, malabsorption and diarrhea.

Pet-to-human transmission of giardia is quite rare. People are usually affected after drinking infected water, not from their pet.

Giardia is not easily seen on a regular fecal exam. If it is suspected, we can run a more specialized stool check with centrifugation. A reliable ELISA test is now available as well. Any of these tests require a small amount of fresh stool.

Coccidia (Isospora) are microscopic intracellular parasites.

We can find immature coccidia (oocyst) microscopically on a fecal exam.

Coccidia can cause young animals and immunocompromised individuals to have diarrhea, sometimes severe. The oocysts can be difficult to eradicate in the environment, particularly in a large kennel, shelter, or boarding facility.

There are safe and effective deworming products that you can buy yourself, such as fenbendazole, a dewormer that used to be available only through a veterinarian.

It’s important, however, to know what parasite you’re treating, how your pet got them, how many times to give the medication, and what to do to prevent re-infection.

Fenbendazole, for example, is effective against tapeworms, roundworms, hookworms and whipworms, but dosing should be carefully formulated for the animal’s weight, and the follow-up care is essential.

On the package of one generic fenbendazole product called safe-guard®, for instance, the company claims its product, if administered for 3 consecutive days, is completely effective for up to 6 months. This is misleading.

Fenbendazole is generally not considered to be effective as a one-time treatment:

If you buy an OTC wormer, please call your vet to get specific instructions to make sure you’re using the proper product.

Under-dosing or not repeating the dose at the proper interval can lead to your pet always living with a low level of parasites.

Empiric deworming means you give your pet a safe deworming medication if you suspect intestinal parasites (worms), even if your vet hasn’t found actual evidence of the worms in a stool sample.

The most common reasons to do this are:

Say a dog or cat has intractable diarrhea, is not responding to diet trials and various medications, and has negative stool samples. In these cases, it’s not only acceptable but recommended to empirically deworm the pet.We suspect worms but can’t find them.

We also suggest deworming puppies, kittens, stray animals, and pets who spend a great amount of time outdoors roaming.

People often ask why I couldn’t find worms in their cats. The simplest answer is that parasites are sneaky pests that don’t show up in all samples. Parasites don’t like:

If you ever find maggots on your cat, see your vet right away. Your vet will most likely find a wound or sore or matted fur that’s been colonized by fly eggs — and maggots have developed.

Your pet will need professional wound care and antibiotics.