Worms in cats: types, symptoms, treatment and risk to people

Worms in cats are intestinal parasites, and the three that matter most are roundworms, hookworms and tapeworms. They are common, they are usually straightforward for a vet to treat, and many cats that have them look perfectly well. Which worm it is matters, because each is caught differently and needs a different medicine.

Most owners find out by seeing something: a long pale worm in vomit, or small rice-like pieces under the tail. Others never see anything, and the worms are found on a stool test.

Roundworms, hookworms and tapeworms: how to tell them apart

Feline roundworm

Roundworms are the most common intestinal worm in cats. Kittens can get them through their mother's milk. Adult cats pick them up by swallowing eggs from contaminated soil or litter, or by eating mice, birds or insects that carry the larvae.

The adult worms live loose in the intestine and often curl like a spring when passed.

Hookworms in cats

Hookworms are much smaller, well under an inch long, and owners rarely see them. They attach to the lining of the intestine and feed on blood. Cats catch them by swallowing larvae from contaminated ground, through the skin of the paws or belly, or by eating infected prey.

Because they feed on blood, a heavy hookworm infection can cause anemia. That is most dangerous in kittens and in cats that are already frail.

Tapeworms

Tapeworms are long, flat and made of segments. The worm stays attached inside the gut, and what you see are the segments it sheds, which look like grains of rice when fresh and like sesame seeds once dry. Cats get the common type by swallowing an infected flea, and another type by eating rodents. There is more detail in the article on tapeworms in cats.

Symptoms of worms in cats

Many adult cats show no signs at all. When signs appear, they can include:

• Worms or segments in vomit, in stool or around the tail.
• Vomiting or diarrhea, sometimes with mucus or blood.
• A pot belly, mainly in kittens.
• A dull, rough coat.
• Weight loss or poor growth despite a normal appetite.
• Licking or irritation under the tail.
• Pale gums, weakness and dark, tarry stool with hookworms.
• A cough, occasionally, as young roundworms pass through the lungs.

Roundworm symptoms are mostly the pot belly, poor coat, vomiting and loose stool. All of these signs have other causes as well. They can point to worms, but only a vet exam and stool test can sort out what is going on.

I found a worm in my cat's vomit

A long, pale, spaghetti-like worm in cat vomit is most often a roundworm. Pick it up with a tissue or glove, seal it in a bag or take a clear photo, and call your vet. Seeing the worm helps them choose the right dewormer.

One worm is not an emergency in an otherwise bright adult cat, but it does mean there are likely more inside. Wash your hands afterward and clean the area. If your cat keeps vomiting, see why an old cat is vomiting, because worms are only one of many causes.

How vets diagnose worms

The main test is a stool sample examined for worm eggs under a microscope. Some clinics also run a test that detects proteins from the worms themselves. Bring a fresh sample if you can, plus any worm or segment you found.

A negative result does not always mean no worms. Eggs are shed on and off, young worms do not lay eggs yet, and tapeworm eggs are often missed. Your vet may ask for samples from more than one day or may treat based on what you saw.

Cat worms treatment

Treatment is a deworming medicine chosen for the type of worm. Dewormers come as tablets, liquids, injections and spot-on products applied to the skin. No single product covers every worm, which is why identifying the worm comes first.

• Roundworms and hookworms. Treated with medicines that kill or paralyze the adult worms in the gut so they pass out in the stool. You may see dead worms in the litter box afterward.
• Tapeworms. Need a different medicine, most often praziquantel. The worm is usually digested, so you may see nothing.
• Repeat treatment. Most dewormers do not kill eggs or every immature stage, so a second treatment is commonly needed. Your vet sets the timing.
• Flea control. Needed for every pet in the house if tapeworms are involved.

The product and the amount depend on your cat's weight, age, kidney and liver health and other medicines, and only your vet can set them. Some dewormers are sold without a prescription, but many cover only one type of worm. Only give one if your vet has confirmed the exact product and amount for your cat, and never use a dog product on a cat. Some dog parasite treatments contain ingredients that are toxic to cats.

Garlic, pumpkin seeds, diatomaceous earth and similar home remedies do not reliably clear worms, and garlic is toxic to cats.

Can humans get worms from cats?

Yes, but it is uncommon and usually not through direct contact with the cat. The risk is highest for young children, who put soil and fingers in their mouths.

• Roundworm. People are infected by swallowing eggs from contaminated soil, sand or litter. The eggs need time in the environment before they can infect anyone, which is why prompt scooping helps. In people the larvae can travel to organs or the eye and cause illness.
• Hookworm. Larvae in contaminated soil or sand can burrow into bare skin and cause an itchy, winding rash.
• Tapeworm. A person would have to swallow an infected flea. It is rare and is seen mostly in small children.

If you are worried about a person in your household, speak to a doctor. Tell them you have a cat with worms.

How to clean the house

• Scoop the litter box at least daily and bag the waste.
• Wash your hands after handling litter, soil or anything your cat has vomited.
• Empty and scrub the litter box with hot water and detergent regularly. Roundworm eggs resist most household disinfectants, so physically removing them matters more than what you spray.
• Wash your cat's bedding on a hot cycle and vacuum carpets and furniture.
• Treat fleas on every pet and in the home.
• Cover children's sandboxes and wear gloves when gardening.

Outlook and prevention

Healthy adult cats usually recover well once the right dewormer is given. Getting worms again is common, because the sources, fleas, prey and contaminated ground, are still there.

Your vet can suggest a routine deworming and flea control schedule based on whether your cat goes out, hunts or lives with other animals. Many regular parasite preventives also cover roundworms and hookworms.

Worms in older cats

Indoor seniors are not exempt. Fleas come in on dogs, visitors and clothing, and plenty of old cats still catch the odd mouse or insect. An older cat should stay on whatever parasite plan its vet advises.

The bigger point is this: in an old cat, weight loss, a pot belly, vomiting or diarrhea is far more often something other than worms. Kidney disease, hyperthyroidism, diabetes, bowel disease and cancer are all more likely. A swollen belly in a thin old cat can also be fluid or a mass.

So a negative stool test should not end the search, and neither should a course of dewormer that changed nothing. Ask your vet about blood and urine tests. The articles on why an old cat is losing weight, why an old cat is so skinny and why an old cat has diarrhea walk through the other causes. Dewormers also need more care in a cat with kidney or liver disease, which is another reason to let the vet choose.

Call the vet today if

• Your cat's gums are pale or white, or it is weak or collapsing.
• There is black, tarry stool or more than a streak of blood.
• Your cat vomits repeatedly or cannot keep water down.
• It has not eaten for a day.
• Its belly is swollen, tight or painful.
• It is breathing fast or with effort.
• A kitten or a frail older cat has worms along with diarrhea or lethargy.
• Your cat seems unwell after a deworming treatment.

If your own clinic is closed, call an emergency veterinary clinic.

This article is general educational information, not veterinary advice. Seeing a worm or a segment can point to a type of parasite but does not confirm it, and the same signs have other causes, especially in older cats. Your veterinarian should choose the dewormer and the amount for your cat. For questions about a person's health, speak to a doctor.