Intestinal worms in cats is not uncommon in Norway, and it is often roundworms and tapeworms that are involved. Cats are more prone to intestinal worms than dogs, because these hunters tend to eat prey they claw at. Read on to learn more about the different types intestinal worms in cats and how to get rid of it!

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Different types of intestinal worms in cats

Coil worm

This is the most common intestinal worm in cats. The adult worms have a long white-yellow color, similar to cooked spaghetti, and measure approximately 5-12 cm in length. The adult worms live in the cat's intestine, but during the larval stage they wander around the body's organs and can form small cysts. 

Like puppies, kittens can be infected with these worms via their mother's milk, and within three weeks there can already be adult intestinal worms in the intestines of the kittens. It is therefore important to give kittens and mother cats regular worming treatments. In rare cases, roundworms can also infect humans, but cats have their own variant of roundworm, known as Toxocara cati. 


Tapeworms are not uncommon either intestinal worms in cats, and you can sometimes see small "rice grains" near the anus or the cat's tail. However, these pose no danger to humans. The tapeworm takes up residence in the cat's intestine and infects via faeces or through prey. The worm's body is long and flat, and composed of several "joints" that contain eggs. 


Lungworms are more widespread in Western Norway, and adult lungworms are approximately 1 cm long. The larvae are so small that they can only be seen under a microscope. The adult worms live in the cat's lung tissue and can cause respiratory symptoms such as wheezing and coughing. Sometimes signs of infection can also be observed on x-rays of the cat's lungs.

It is important to note that not all dewormers are effective against lungworms, so if infection is suspected, it is recommended to carry out an analysis of the cat's faeces to get an accurate diagnosis.

Close-up of roundworm (Toxocara cati) from a cat. Intestinal worms in cats
Roundworm/roundworm (Toxocara cati) - Source: Wikipedia

How are intestinal worms transmitted?

Cats become infected by ingesting the eggs that lie on the ground after an infected animal has defecated, or by eating so-called intermediate hosts such as mice, other rodents, certain insects or earthworms. Fresh faeces do not contain infection, as it takes at least three weeks from the time a dog lays eggs in the faeces until the eggs become infectious. Inside each egg is a small larva that must develop, and the time this takes depends on temperature and humidity, and can vary from three weeks to several months.

If cats eat infected eggs, these hatch in the cat's gut. The larvae migrate from the intestine through the body to the liver, then to the lungs before being coughed up, swallowed again, and adult roundworms can lay new eggs in the intestine.

Symptoms of intestinal worms in cats 

Infection with roundworms can be asymptomatic, but if the cat has large amounts of worms, the condition can lead to poor growth in kittens, poor fur quality, a generally impaired general condition and gastrointestinal symptoms such as vomiting, diarrhea or weight loss. Wandering larvae can cause respiratory symptoms in kittens and more serious illness. Eggs from intestinal worms can be detected in the faeces by microscopic examination in a laboratory. Occasionally, roundworms can also be seen in vomit or faeces. 

Other general symptoms that can appear with intestinal worms in cats 

  • weight Reduction
  • Bleeding prolapse (third eyelid becomes visible in the corner of the eye or partially covers the eye, in one or both eyes)
  • Vomiting
  • Reap
  • Dull fur, fur loss
  • Licking/itching and red skin in the anal area
  • Distended stomach

How to treat intestinal worms in cats?

We recommend that outdoor cats are treated against intestinal worms 3-4 times a year, especially if cats like to hunt. It is also a good idea to treat cats that are only outside once in a while or that go out on a leash. For indoor cats, worming once a year, or as needed, is often sufficient. 

For kittens, deworming is recommended at 2, 4, 6, 8 and 12 weeks of age, then at 6 months and 12 months of age. If you have a mother cat who is still nursing, it is wise to treat both mother and kittens at the same time when the kittens are 2, 4 and 6 weeks old. Remember to inform your vet that the mother has kittens, so that you get a prescription for the correct worming treatment.

There are different types of dewormer, and the medicine is available both as drops applied to the neck, oral paste and tablets.

Can you get a cat dewormer without a prescription? 

Deworming for cats and dogs requires a prescription in Norway, to avoid excessive medication use and incorrect medication. To prevent the development of resistance, it is important that the animal receives the correct medicine, which is adapted to the individual situation. A veterinarian will be able to make a correct diagnosis and prescribe the most suitable medicine for your particular cat. At the same time, the vet can provide you with useful information about how the cat should be wormed, as well as possibly arranged treatment. In our veterinary clinic in Larvik, you can get a prescription for deworming for both cats and dogs.

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Elisabeth is a veterinarian and authorized ophthalmologist with specialization in eye surgery, as well as further training in internal medicine, general surgery, oral surgery and ultrasound from the European School for Advanced Veterinary Studies in Toulouse.