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Roundworm in Cats: Vet Approved Signs, Causes & Treatment


May 1, 2023


Dr. Paola Cuevas Photo

The information is current and up-to-date in accordance with the latest veterinarian research.

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There are many animal species that can get roundworms, which are parasites that live inside the intestines. Cats fall into this category.

In fact, roundworms are one of the most common intestinal parasites in felines.1 Luckily, they aren’t often deadly or very serious, though they can be in at-risk cats and kittens. Most cats become infested with roundworms at some point in their lives.

Below, we’ll look at all the signs of roundworm infestation, as well as the causes and potential treatments.


What are Roundworms in Cats?

Roundworms are one of the most prevalent types of parasites that cats can get. They don’t always cause any signs of illness or harm to the cat. However, if the feline is already sickly, very young, or very old, they can cause illness and even death. Complications are common in kittens with heavy roundworm infestations. 

Therefore, it’s important to follow any deworming schedule your vet suggests and watch for signs of infestation. Unlike other parasites, roundworms do not attach to the wall of the intestine.

sick cat
Image Credit: one photo, Shutterstock

What Are the Signs of Roundworms in Cats?

Roundworms are not very harmful to adult cats. Therefore, it’s common for cats to be infested without any signs at all. In this case, you may not know your cat has roundworms until they’re diagnosed by the vet (or develop signs later on).

Large numbers of roundworms can cause problems for kittens and older cats. Often, these demographics are the ones that show the signs. Kittens may have a large stomach, decreased appetite, dull coat, abdominal pain, diarrhea, and poor growth.

You may not always notice signs in kittens, either, especially if they are healthy overall and only have a few roundworms. Likewise, you may notice roundworms in your cat’s stool or vomit, even if their infestation isn’t terribly serious.

What Are the Causes of Roundworms in Cats?

Most kittens become infested with roundworms through their mother’s milk. The roundworm larvae are present in the mother’s milk-producing glands and then passed to the kitten. Most kittens become infested in this way, especially if the mother wasn’t dewormed before becoming pregnant.

However, there are other ways cats can become infested, too. Roundworms start out living in a cat’s intestines, where they lay eggs. These eggs pass through the cat’s intestines and into their feces, which are then deposited into the environment.

From there, the eggs may end up inside another cat in several different ways. An uninfected cay may lick or bite contaminated plants, for instance. If the cat picks up the eggs on their coat, they may consume them while grooming. Mice and other rodents may also consume the eggs. When the cat hunts and ingests the infested mouse, they will become infested too. Once the roundworm eggs are in the cat’s digestive tract, the cycle starts all over again.

newborn kitten drinking milk from mother cat's nipple
Image Credit: Rembolle, Shutterstock

How Do I Care for a Cat with Roundworms?

Caring for a cat with intestinal roundworms is often pretty straightforward. While this condition does need treatment by a vet, the treatments are often fast and effective. In most cases, the vet will prescribe dewormers. Then, the dead roundworms will pass through the cat’s stool. Effective treatment will also include some home management with specific attention to organic waste management. Keep in mind that intestinal roundworms of cats can infest humans, so please make sure you follow the vet recommendations of keeping the litter box clean and increasing general hygiene standards such as regularly washing your hands.

Usually, the vet will recommend two or three treatments, as the larvae won’t be affected by the treatment. You must wait for the larvae to grow into adults, treat them again, and hope you do so before the larvae start laying eggs.

Kittens are routinely dewormed during their vaccination visits. It’s a fairly common practice that helps prevent kittens from developing more severe illnesses. Nursing females are often treated at the same time as their kittens to prevent them from continuously giving roundworms back to their babies.

However, something very important to consider is that you should never take it upon yourself to medicate your cat. A veterinarian must consider the possibility of a cat also being infested with heartworm or lungworms before starting an intestinal deworming schedule against roundworms. Some cases require additional treatments to prevent issues. While your cat is undergoing a vet-prescribed treatment, there is little you must do to support them. Often, the cat may feel sick for a day or so while the medicine works. However, many bounce back and never experience any adverse effects from the medication. Just make sure to follow your veterinarian’s prescription and ask any questions you might need clarification on. Also, let your veterinarian know if you notice any negative effects on your cat.


FAQs About Roundworms in Cats

How serious are roundworms in cats?

Roundworms in cats aren’t often very serious. In fact, cats may not even show signs of infestation in most cases. Usually, only young kittens get serious infections, which is why they are regularly dewormed.

Can I catch roundworms from my cat?

People can become infested with roundworms. If you clean your infested cat’s litterbox, you may inadvertently transmit the worms to yourself. Children who stick everything in their mouths are particularly at risk.

Do I need treatment if my cat has roundworms?

You may want to seek out a doctor’s advice on treating you and your family if your cat (or another pet) has roundworm. It is possible to catch roundworms from your cat. Luckily, they don’t usually cause much of a problem for most people.

How do I clean my house after a roundworm diagnosis?

You should vacuum the floor and clean other surfaces with an all-purpose cleaner. Roundworms aren’t particularly resistant to regular cleaning. Therefore, most households don’t need to do anything particularly special. Litterboxes and bedding may require special attention including regular cleaning and disinfection.

Can roundworms live in cat litter?

Roundworm eggs can live in cat litter. Therefore, cats will pass roundworms back and forth to each other through their litterbox. Often, when you deworm one animal in the household, you should deworm all the animals in the household, including the dogs.



Roundworms often aren’t serious in cats. Most won’t show signs of the infestation, as the roundworms don’t cause any negative side effects (most of the time). However, they can cause problems for some at-risk felines, like kittens and seniors. Cats with underlying health conditions may also be more likely to develop a serious infestation.

With that said, most vets do recommend deworming cats with roundworms. While they may not cause serious illnesses usually, there is always a risk of complications when a cat is infested.

Featured Image Credit: Todorean-Gabriel, Shutterstock

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