Roundworms in cats: causes, symptoms and management

What are roundworms in cats?​

Roundworms are the most common type of worms affecting cats in the UK. Globally, it’s estimated that there are 134 million cats with the condition. Although not often life-threatening, roundworms can cause significant illness, particularly in kittens and older cats. Healthy adult cats usually don’t become seriously ill as a result of roundworm, although it’s possible for large infestations to cause an intestinal blockage.

Roundworms live in a cat’s intestine and lay eggs, which are expelled in their poo. It’s estimated that, every single day, adult worms release about 200,000 eggs a day through the poo of their hosts. Roundworms are contagious and can infect other animals, such as dogs, and people, posing a health risk to you and anyone else in your home. Thankfully, they can be prevented in cats with regular worming treatment. 

What do roundworms look like?

Roundworms look like cooked spaghetti and can grow up to 10-15 cm long. In most cases you won't see them in your cat’s poo, unlike tapeworm - another common worm in cats. That’s why regular preventative treatment is the best course of action.

What causes roundworms in cats​

Cats get roundworms by eating their eggs, which are found in the poo of infected animals, or by eating the infected animals themselves, such as rodents and birds. Roundworm can also spread when cats come into contact with an infected surface, for example when cleaning themselves after touching infected soil or sand. Kittens are commonly infected through their mother’s milk and should be routinely treated for worms from when they are just a few weeks old.

What do roundworms do to cats?

After a cat consumes the worm’s eggs, they hatch into larvae in their intestine and can travel to other parts of their body including the muscle, liver and lungs. They grow into adult worms before returning to the intestines where they lay eggs, which are then passed in their poo, ready to infect other animals or people. 

Roundworms consume the cat’s intestinal contents - food that the cat has eaten and is waiting to be absorbed by the intestines to process into energy, growth and vital nutrients for the body. Kittens therefore face the biggest risk from roundworms as they prevent the kitten getting the nutrients they need to grow and thrive. This makes them more vulnerable to other illnesses. As a result, roundworms can sadly be a cause of death in young kittens.

Signs of roundworm in cats

Cats with roundworms don’t always display any symptoms and you can’t usually see worms in their poo unless they have particularly high numbers of worms. It’s particularly important to keep an eye out for any symptoms in kittens due to the life-threatening nature of the condition. If you’re worried that your kitten might be affected, get in touch with your vet right away.

Symptoms of roundworm can include:

• Poor/slow growth 
• Pot bellied appearance
• Weight loss
• Increased appetite
• Weakness
• Dull, dry coat
• Diarrhoea
• Coughing
• Worms in poo or vomit (but this is rare)

Treatment to get rid of roundworms in cats​

Your vet can prescribe treatment to get rid of the roundworms, which usually comes in liquid, tablet or topical (spot-on) form. Your cat will typically need more than one course of treatment, given a few weeks apart, to effectively target worms at each stage of their lifecycle and make sure none are left behind. 

Once they have finished treatment, your vet will test your cat’s poo again to confirm there are no eggs remaining. This should be followed up with routine worming treatment to reduce the risk of future infections.

Treating roundworm in kittens

As roundworm is so common in kittens and presents such a risk to their heath, it’s vital that they're treated for worms regularly. Treatment often starts when they’re just a few weeks old and is given as often as every two weeks for the first few months of their lives.

Worming treatments specifically for kittens are available, as treatment for older cats might not be safe for kittens. Have a chat with your vet as they can advise you on the best product for your kitten. Worming products and schedules in adult cats depend on various factors, such as whether they have outdoor access and whether they hunt, so always discuss this with your vet.

How to prevent roundworms in cats​

Roundworms are very common in the environment, so it’s hard to avoid them. Sticking to a regular worming routine is the best way to prevent roundworm infections. Worming treatments can usually be given at home every few months. Your vet can prescribe the most suitable medication for your cat. 

Pet Health Club members get a discount on all worm, flea and tick treatments plus many more benefits to keep your cat healthy and happy. Find out more about our monthly plans here.  

Other prevention methods include cleaning your cat’s litter boxes daily and disinfecting regularly, as well as disposing of any outdoor poos right away.

Can humans get roundworms from a cat?

Humans can get roundworms from touching infected poo or surfaces such as soil or sand and then putting hands near or in the mouth. It’s not very common here in the UK but there’s still a risk. If someone touches a contaminated item and then touches their mouth, the eggs can enter their body and cause symptoms including sickness and diarrhoea. 

You can prevent the risk by washing your hands after touching anything that’s potentially infected, disposing of poo right away and deworming your cat regularly.

Can I give my cat dewormer without going to the vet?

A good worming routine is all part of being a responsible cat owner – and it’s vital to protect your cat or kitten from the dangers of these unpleasant parasites. You can usually give your cat their routine worming treatment at home, but if you’re having difficulty you can ask your vet for help.

Some worming products will need to be prescribed by a veterinary surgeon. When you are dealing with a suspected or confirmed roundworm infestation you should include your vet as they can help you with the most effective treatment plan.

Academic research on roundworm in cats

Global presence in public outdoor spaces

A 2018 study looked at the prevalence of toxocara — one of the most common forms of roundworm — in public places around the world. It found that 21% of outdoor spaces, including public parks and beaches, were contaminated with toxocara eggs, highlighting just how common it is around the world.

Expert advice on preventing roundworm in your cat

For expert advice on roundworm prevention or treatment for your cat or kitten, contact your local vet.

Find your nearest vet using our Find a Vet page, or speak to a vet online using Online Vets.