Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Roundworms in Cats: Causes, Signs & Care (Vet Answer)

Share

peaceful happy calico short hair cat with white stomach sleeping ground surface carpet

If you own a cat, you do need to be aware of them getting worms. Worms are not pleasant to think about, but if they infect your cat, it can lead to a lot of problems. Worms can have serious consequences for our feline friends.

Roundworms are one of the more common intestinal parasites found in cats, so it is important for them to be on a cat owner’s radar. Continue reading to learn more!

divider cats oct 2024

What Are Roundworms in Cats?

Roundworms are a common parasite that takes residence in the intestines of cats. This is the perfect location for roundworms to settle down, where they can consume the food that has been broken down and digested by the cat’s stomach, grow into adults, and continue their lifecycle. Roundworms are large white or light-brown worms that average 3–6 inches long and can sometimes be clearly seen with the naked eye in a cat’s vomit or feces. However, often, we may never see them.

There are numerous species of roundworms, with two species causing illness in cats: Toxocara cati and Toxocara leonina. Rather alarmingly, almost all cats will become infected with roundworms during their lives.

cats roundworms
Image By; Todorean-Gabriel, Shutterstock

divider cats oct 2024

What Are the Signs of Roundworms?

Healthy adult cats may never show signs of roundworm infection. However, a large worm burden in young kittens, elderly cats, or those with underlying health issues may be extremely harmful and sometimes life-threatening. Clinical signs to look out for include the following:

  • Vomiting and diarrhea
  • Weight loss
  • Lethargy and fatigue
  • A pot-bellied appearance
  • A dull, lackluster coat
  • Poor growth
  • Coughing
  • Pneumonia

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

Preventative wellness PGV mention keep cat healthy Preventative wellness PGV mention keep cat healthy mobile

What Are the Causes of Roundworms?

Let’s start with the adult worm swimming freely in the intestine of your cat. Once this adult roundworm reaches maturity, it will pass eggs in the feces of the cat. This egg contains the embryonic worm, and now, in the environment, will spend 2–4 weeks developing into larvae before it is able to infect a new “host” or cat.

These eggs are extremely hardy and can remain infectious in the environment for months or years. This means that even once the feces have dissolved into the soil, the worm eggs remain within the ground, able to infect any cat that happens to encounter, then ingest, it.

However, they can also infect other animals, such as rodents or birds, which act as “transport” hosts. The larvae will not develop into mature adults within these animals, but they are able to remain encysted within their tissues, waiting for the time when an unsuspecting cat will ingest the transport host and become infected.

Once inside the cat’s body, the larvae don’t immediately settle in the intestine but migrate to the liver (where they will go dormant and form cysts) and the lungs. In the lungs, they will continue their development, burrowing into the small airways before traveling up to the throat, where they are coughed up and swallowed back into the intestinal tract. Now we are back where we started: the worms will mature into adults, ready to release eggs and begin the lifecycle all over again.

If the infected cat is a pregnant or nursing mother, they can also migrate to the mammary glands, where they will infect nursing kittens through the milk.

veterinarian examining a bengal cat at the clinic
Image Credit: Pressmaster, Shutterstock

How Do I Care for a Cat With Roundworms?

If you suspect that your cat has worms, then it is important to seek veterinary attention. Thankfully, the treatment for roundworms is relatively simple and cost-effective, and your vet will prescribe the appropriate dewormer designed to kill the adult worms in the intestines.

Because the dewormer does not act upon the migrating larvae in the lungs, two or three doses of the medication are required, typically administered at 2- to 3-week intervals. In kittens and pregnant mothers, it is especially important that they are given worming medication, so talk to your veterinarian about the correct protocol for prevention. Similarly, all adult cats should be on a worming prevention protocol, and this is normally covered at your cat’s annual health check and booster vaccinations.

For prevention, it is important to ensure that any litter trays in the house are cleaned daily and disposal of any feces in the garden or play areas is undertaken.

divider cats oct 2024

Frequently Asked Questions (FAQ)

Can Humans Catch Roundworms from Cats?

Roundworms can have an impact on human health. It is thought that the incidence of Toxocara cati in humans has been underestimated, and children are especially vulnerable to health implications should they be infected by roundworms. The immature stages of the worm—the larvae—can cause cysts in various organs and, rarely, blindness.

Therefore, especially in households where cats cohabit the home with children, it is important that the cats are on appropriate parasite prevention. Children should not have any access to litter trays and, ideally, no access to areas where the cat eliminates outside. This can obviously be difficult in a yard, where large numbers of eggs can accumulate in the soil, so ensure that the children have a strict hand-washing routine after playing. Be mindful of the risks of children playing in uncovered sandpits and parks.

cat sitting on owners lap
Image Credit: Pixel-Shot, Shutterstock

How Are Roundworms Diagnosed in Cats?

Your veterinarian will be able to confirm infection through a test called a “fecal flotation test”. A sample of your cat’s stool will be mixed with a solution that allows the eggs to float to the top of the solution, where they are able to be sampled onto a glass slide and inspected under a microscope. Worm eggs all have different characteristics that allow for appropriate identification. So, whilst they may be clever little creatures, the human curiosity to understand this microscopic world has given us the ability to be able to treat parasites effectively.

divider cats oct 2024

Conclusion

Despite the general shudder that goes down our spines when we think about worms occupying our cat’s bodies, roundworms pose an important health risk that demands our attention spans long enough to consider appropriate preventative measures. If you are a cat owner, then it is important to ensure that your cat is receiving regular dewormer, especially if you have recently acquired a kitten or are responsible for a pregnant or nursing queen. Roundworm infection can be insidious and go completely unseen, so as always, I’ll leave you with a veterinarian’s favorite advice: prevention is better than cure!


Featured Image Credit: Kristi Blokhin, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Chatting About Fake News in the Pet World, AI Again, and New Age Journalism | Chatty Cattys, Episode 23

Navigating the modern digital landscape requires a sharp eye to distinguish fact from fiction. In this episode of Catster’s podcast, Chatty Cattys, Nicole...

The Surprisingly Sweet Reason Behind Cats Chewing Human Hair (and Others)

Cats have a talent for turning the ordinary into something slightly bizarre. One minute, there’s a peaceful evening on the couch, and the...

Could This 19th-Century Technology Save Raw Pet Food? How E-Beams Are Changing the Industry

One of the most important developments in the pet food industry over the last century was the ability to create meals that were...

Why 2026 Is Being Called the “Year of the Cat”

Cats Are Finally Getting the Attention They Deserve Cats are having a major cultural moment, and the numbers help explain why. According to...

More related

CBD for Cats: Pros, Cons, Uses & Safety (2026 Update)

Review Summary Disclaimer: The information presented has been fact checked by one of our in-house veterinarians, However, this is not a recommendation, prescription,...

Siamese Cat vs. Oriental Shorthair Cat: Which One To Choose (With Pictures)

Both the Siamese and Oriental Shorthair have similar physical traits. It can be hard to tell the difference between these two breeds, which...

Are Black Cats in Danger on Halloween? The Real Problem Explained

The Halloween season is a magical time of year. A cool nip is in the air, all things creepy are fun, and curling...

9 Best Calming Collars for Cats in 2026 – Reviews & Top Picks

Cats suffering from anxiety and stress can misbehave, act aggressively, and even develop health problems that can include diarrhea. It’s not always easy...

Keep reading

Why Do Cats Shake or Vibrate Their Tails? Vet-Verified Reasons Explained

When cats shake their tails it’s just one of a series of ways in which your cat communicates with you. It is important to consider context, but his or her tail can swoosh, wag, perk up, or remain motionless. It...

cat tail

Feline Upper Respiratory Infection: Vet Reviewed Causes, Signs & Care

Respiratory infections are unfortunately pretty common in cats, but are they something your cat will get over, or do you need to take them in to see the vet? And what about secondary illnesses? We’ll take a closer look at...

A cat having a check-up at a small animal vet clinic

Can Cats Eat Okra? Vet Reviewed Nutrition Facts & Alternatives

If you love okra and would like to share some with your cat, you should know that cats can only eat okra in small amounts. Just remember that your cat is a carnivore that needs to get most of their...

Can Cats Eat Okra

Why Is My Cat Laying On Me All of a Sudden? 12 Vet-Reviewed Reasons

If you have a standoffish cat or one that simply doesn’t care much for snuggling, it can be special when your cat suddenly attempts to lay on you or cuddle with you. However, it can also be a sign that...

cat-sleeping-on-owners-lap

The History of Commercial Pet Food: Invention & Timeline

Most cats and dogs today eat commercial pet food, but when was pet food invented, and at what point did it become popular? Dry biscuits for dogs were first sold around 1860 in the UK and were the creation of...

10 Halloween Safety Tips for Your Cat: Vet-Approved Advice

While there’s a strong association between cats and Halloween, many cats can feel spooked or stressed out during this holiday. New Halloween decorations, trick-or-treaters visiting your door, and other changes in routine can cause cats to feel uneasy. Therefore, it’s...

black cat surrounded with halloween pumpkins

How to Prevent Diabetes in Cats: 7 Vet-Reviewed Tips

Feline diabetes is a severe illness that can drastically decrease cats’ quality of life. Pets with this condition cannot properly use glucose because they don’t produce enough insulin or because their bodies have become resistant to the hormone. It’s a...

cat vaccination

How to Put a Cat on a Diet: How, Why & 4 Vet-Approved Steps to Follow

As you may or may not know, cat obesity is a problem in the United States, so much so that up to 63% of cats are deemed overweight 1. If you have an overweight cat, helping your cat shed that...

grey domestic hungry cat

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.