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- Your cat may have worms if they are vomiting, losing weight, or you see worms in their stool.
- Cats may get roundworms, tapeworms, hookworms, or heartworms.
- You can treat a worm infestation with anti-parasitic medications.
- Visit Insider's Health Reference library for more advice.
Worms are a common issue for cats. In fact, as many as 45% of cats have worms at any given time.
"Worms are common, especially in kittens, newly adopted cats, and cats who spend time outdoors," says Amanda McNabb, DVM, a veterinarian in private practice.
Your cat may show symptoms of worms, such as vomiting – but not all cats exhibit signs of a worm infestation.
Worms are not always dangerous, but severe worm infections can damage your cat's intestines, cause weight loss, or even lead to death in kittens. That's why it's important to get regular checks from your vet and take steps to prevent and treat worm infections.
Here's what you need to know about how cats get worms and what to do if your cat is infected.
Signs that your cat has worms
"Healthy adults may not have symptoms from worms, which is why your vet tends to recommend periodic fecal testing," McNabb says. But in some cases, your cat may show symptoms of a worm infection including:
- Vomiting
- Diarrhea or soft stool
- Loss of appetite
- Blood in stool
- Weight loss
You may also be able to see worms in your cat's stool or vomit. Each type of worm has a different size and shape, Nichols says.
Types of worms in cats
Some of the most common worms that infect cats are roundworms, tapeworms, hookworms, and heartworms. Here's how to identify them:
Roundworms look like cooked spaghetti. They infect the intestines and are the most common worms found in cats. Roundworms may not cause any symptoms, but major infections can cause vomiting, weight loss, or a pot-bellied appearance.
Tapeworm segments look like dried grains of rice or flat white sunflower seeds, and are often moving or crawling around the rectum.
Tapeworms tend to be more common in older cats and cats that hunt. Your cat may not show any symptoms of tapeworms, but in some cases, there may be vomiting and weight loss.
Hookworms look like shorter spaghetti noodles, measuring about two inches long. Hookworms have a ribbon of brownish-red down the body and a hooked shape.
They are a small form of roundworm that can damage the lining of your cat's intestine. Hookworms feed on blood from the cat's small intestine and can cause anemia and weight loss.
Heartworms don't show up in your cat's stool or vomit which is why it's important to see your vet once a year to screen for heartworms, says Jess Nichols, DVM, Chief Veterinarian at the Pet Resource Center of Kansas City.
"The most common behavioral change is less energy or more grooming around its rear end," Nichols says. You may also notice that your cat has a lower appetite. But not all cats with heartworms exhibit behavioral changes
Heartworms are rarer in cats but can cause serious harm to your cat's heart and lungs. In untreated cases, heartworms can lead to trouble breathing, weight loss, or in some cases, sudden death.
How your cat can get worms
There are several ways that your cat can get worms, including:
- If your cat goes outside, one of the following: worms, worm eggs, or fleas carrying worm eggs can get caught on your cat's coat. The cat can then ingest the eggs while grooming themselves or grooming other cats, says Travis Arndt, DVM, Medical Director at the Animal Medical Center of Mid-America.
- Shared litter boxes or outdoor areas where cats poop may also contain worm eggs, McNabb says.
- Kittens often get infected through breast milk when their mothers have a dormant case of worms, says Nichols.
- "Some worms are also found in muscle tissue of infected animals, so cats who hunt or are fed raw meat products can ingest worms through their diet," McNabb says.
Treatment of worms
If your cat does get infected with worms, there are several treatment options.
"Fortunately, there are safe, effective anti-parasitic medications available," McNabb says. Some of the most common medications include pyrantel, pamoate, fenbendazole, and, for tapeworms, praziquantel.
"It is best to have a fecal test to identify the worm to select the most appropriate medication," McNabb says.
Anti-worm medications can work in as little as one to two days, but you may still see worms in your cat's stool for days afterward. You should always follow your veterinarian's directions and give your cat the full course of medication.
Prevention of worms
There are important lifestyle changes you can make to help prevent worm infections in your cat.
"The best way to prevent your cat from being infected with intestinal parasites is by limiting their exposure to outside, where stray cats and wildlife may contaminate the environment," Arndt says.
It's also important to only feed your cat cooked foods, as raw foods are more likely to be infected with worm eggs that could infect your pet, McNabb says.
These changes may not work for all cats, so you can also use worm-prevention medications. Feline heartworm preventives like Heartguard and prescription flea preventives like Frontline can help stop worms, McNabb says.
Insider's takeaway
Worms are a common problem, but if you don't take steps to prevent and treat them, they can have serious harmful effects on your cat. There are several key signs that your cat has a worm infection, including diarrhea, loss of appetite, and worms in their stool.
Keeping cats inside and only feeding them cooked food can help prevent worms, along with flea and heartworm medications. "Speak to your cat's veterinarian about their recommendations that will work best for your cat to keep them healthy and parasite free," Arndt says.