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)

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!

PangoVet_Mention-in-Content for PangoVet2 save money

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

Why Do Cats Like Watching Other Animals? Vet-Reviewed Feline Behavior

Cats spend a good portion of their day observing their environment. Other animals are of particular interest for felines, whether it is a...

Are Zebra Plants (Haworthia) Poisonous to Cats? Vet-Reviewed Houseplants Examined

Haworthia plants—also known as “zebra plants”—are stylish, easy-to-care-for houseplants popular with beginners and long-time plant lovers alike. If you have cats, it’s normal...

Can Cats Eat Chia Seeds? Vet-Approved Nutrition Facts & FAQ

Chia seeds are most associated with those tasty chia puddings that you see all over social media. Maybe you haven’t thought about giving...

Why Do Cats Drink Out of the Toilet? 6 Reasons & Vet-Reviewed Solutions

Cats drinking out of toilets can be unpleasant, but it does happen. If you have a cat that loves to drink out of...

More related

42 Luxury Cat Gifts for Cat Lovers & Their Cats

With the holiday season quickly approaching, many of us are searching for the perfect gift for the friends and family members on our...

The 5 Best Freeze-Dried Cat Foods of 2026 – Vet-Verified Reviews & Top Picks

Freeze-dried cat food is the easiest way to feed your pet a natural raw diet that reflects what a cat would eat in...

How to Cat Proof Blinds: 7 Helpful Tips to Try Today

Cats and blinds aren’t a great mix, as any cat parent knows. While cats may enjoy batting at dangling cords or trying to...

Lykoi (Wolf Cat) Health Problems: Our Vet Explains 5 Common Issues

Lykoi cats are also known as wolf cats or werewolf cats. Since the breed’s development, they have become increasingly popular, but you may...

Keep reading

How Do Cats Really Feel When You Work From Home? Cat Feelings Explained (Vet-Reviewed)

The COVID-19 pandemic made working from home more common. Many people have had to learn to make adjustments to new work habits and lifestyles. Consequently, pets have also had to get used to spending more time with their parents. Cats...

woman working on her laptop with her cat on the couch

10 Best Cat Foods for Senior Cats in 2026 – Reviews & Top Picks

It’s a privilege to share your life with a beloved feline companion. The changes that cats undergo as they pass through middle age into advanced seniority require some lifestyle changes. At some stage, you may need to consider adjusting their...

black and white old cat eats from a plate

Why Does My Cat Lick My Hand & Fingers So Much? 7 Vet-Reviewed Reasons

A dog licking your hand is normal, and it’s how they show affection. However, a cat is a different story. Felines aren’t widely known for their licking behavior toward humans, and it’s strange when they begin licking our hands and...

cat-licking-human-fingers

Cat Toothache Pain: Vet-Reviewed Signs & How to Help

Did you know that February is Pet Dental Health Month? It’s true, and though this facet of our pet’s care is often forgotten about, it is very essential. Just as with humans, your cat’s dental health can affect their entire...

vet checking cats teeth

7 Best CBD Cat Treats in 2026 – Reviews & Top Picks

The world of cat treats is constantly evolving, especially if you’re looking for some natural medical benefits from the treats too. Unfortunately there are no cat-specific CBD treats, although CBD has been recently shown to be well tolerated in healthy...

blue-maine-coon-having-treats

Why Does My Cat Wake Me Up Every Morning? 5 Vet-Reviewed Reasons

Some cats wake up their human companions in the wee hours of the night for whatever reason. There are also those that somehow know how to wake up their humans at the same time every morning, no matter what day...

cat sleeping with its owner on the bed

Fish Oil Benefits for Cats: Vet-Approved Tips & Health Effects

While shopping for cat food you may have noticed that many recipes include fish oil in their ingredient list, especially higher-quality recipes. You may have even seen some fish oil supplements on the shelves of your local pet store. Fish...

cat reaching out on fish oil capsules

What to Do When a Cat Bites You: Vet-Reviewed Steps to Take & Risks

It may be hard to believe that your beloved kitty would ever bite you, but cat bites and scratches happen more often than you might think. Approximately 66,000 hospital emergency visits occur every year due to cat bites. If you’ve...

The cat bites the woman's hand