Cats can acquire a variety of intestinal parasites, including some that are commonly referred to as “worms.” Infestations of intestinal worms can cause a variety of symptoms. Sometimes cats demonstrate few to no outward signs of infection, and the infestation can go undetected despite being a potentially serious health problem. Some feline parasitic worms are hazards for human health as well.
Common Types of Worms in Cats
Outdoor cats and those who are routinely exposed to soil where other animals defecate are prone to worms. Kittens and cats who do not receive regular preventative health care are most at risk for developing complications associated with internal parasites.
- Roundworms are the most common internal parasites in cats. Resembling spaghetti, adult worms are three to four inches long. There are several ways cats can become infected. Nursing kittens can get roundworms from an infected mother’s milk, while adult cats can acquire them by ingesting eggs from the feces of an infected cat.
- Hookworms are much smaller than roundworms—less than an inch long—and reside primarily in the small intestine. Because they feed on an animal’s blood, hookworms can cause life-threatening anemia, especially in kittens. Hookworm eggs are passed in the stool and hatch into larvae, and a cat can become infected either through ingestion or skin contact.
- Tapeworms are long, flat, segmented parasites that range from 4 to 28 inches in length. An infestation can cause vomiting or weight loss. Cats acquire tapeworms by ingesting an intermediate host, like an infected flea or rodent. When cats are infected, tapeworm segments—actual pieces of the worm that resemble grains of rice—can often be seen on the fur around a cat’s hind end.
- Lungworms reside in the lungs of a cat. Most cats will not show any signs of having lungworms, but some can develop a cough. Snails and slugs are popular intermediate hosts of this type of parasite, but cats are usually infected after eating a bird or rodent who has ingested an intermediate host.
- Though means of transmission can vary, one of the main ways that cats get worms is through the ingestion of the feces of infected felines. Mother cats can also pass on worms to their kittens.
- Keep your cat indoors to avoid exposure to infected cats, rodents, fleas and feces.
- Make sure your home, yard and pets are flea-free.
- Practice good hygiene and wear gloves when changing cat litter or handling feces. It’s also important to frequently dispose of stool.
- Ask your veterinarian to recommend an appropriate internal parasite treatment or prevention program for your cat.
Symptoms of Worms in Cats
Symptoms differ depending on the type of parasite and the location of the infection, but some common clinical signs include:
- Worms visible in stool or segments of worm seen near anus
- Bloody stool
- Bloating or round, potbellied appearance to abdomen
- Weight loss
- Trouble breathing
If you think your cat may have worms, it’s important to bring her to a veterinarian, who can confirm the presence of worms. Avoid self-diagnosis, since worms are not always visible or identifiable.
Treatment for Worms
Please don’t attempt to treat your pet yourself—your cat should be treated for the specific type of worms he has.
- Not all dewormers eradicate all types of worms. Your veterinarian will determine the type of worm(s) infestation(s) your cat has, and prescribe the best course of treatment. Your veterinarian will also be able to tell you if the dewormer should be repeated, and when.
- Not all dog medications are safe for cats.
- Some over-the-counter deworming medications can be harmful if used inappropriately.
Transmission of Worms from Cats to Humans
A large number of roundworm eggs can accumulate where cats defecate. People, especially children, who ingest such eggs can develop serious health problems, such as blindness, encephalitis, and other organ damage. Treatment of blindness caused by roundworm may involve surgical removal.
Hookworm larvae can penetrate human skin and cause lesions. People can acquire tapeworms through the ingestion of an infected flea, although this is rare.
Although the name suggests otherwise, ringworm isn’t caused by a worm at all—but a fungus that can infect the skin, hair, and nails. Not uncommon in cats, this highly contagious disease can lead to patchy, circular areas of hair loss with central red rings. Also known as dermatophytosis, ringworm often spreads to other pets in the household—and to humans, too.
Classic symptoms of ringworm in cats include:
- Skin lesions that typically appear on the head, ears and forelimbs.
- Ringworm can cause flaky bald patches that sometimes look red in the center.
- In mild cases, there may be localized areas of redness or simply dandruff, while more severe infections can spread over a cat’s entire body.
- It’s also possible for a pet to carry ringworm spores and not show any symptoms whatsoever.
A cat can get ringworm directly through contact with an infected animal—or indirectly through contact with bedding, dishes, and other materials that have been contaminated with the skin cells or hairs of infected animals. Ringworm spores are notoriously hardy and can survive in the environment for more than a year!
- Any cat can develop ringworm, but kittens less than a year old and geriatric cats are most prone to infection.
- Long-haired cats and those who are immunocompromised are also more susceptible.
- Ringworm can quickly spread in shelters or other crowded environments.
- Warm and humid conditions tend to promote ringworm infections.
Because infection can potentially spread over a cat’s body, it is important that you see your vet for an accurate diagnosis if you suspect your pet has ringworm. And because the infection can easily spread to you and other animals in the household, it’s a smart idea to immediately quarantine your cat until a veterinarian can confirm a diagnosis. You should also thoroughly wash your hands after you touch your cat.
- Since some cats show few or no symptoms, a diagnosis of ringworm is rarely made just by looking at the skin.
- A veterinarian may use an ultraviolet light to diagnose ringworm, or may examine a fungal culture taken from a cat’s hair or skin cells.
- Skin biopsy and microscopic exam are sometimes also performed.
Treatment of ringworm depends on the severity of the infection.
- A veterinarian may prescribe a shampoo or ointment that contains a special medication to kill the fungus.
- In some cases, oral medications are necessary.
- To ensure that you’ve eradicated this resistant and hardy fungus, treatment may have to be given for several months or more and fungal cultures rechecked periodically.
- It’s also important to treat the cat’s environment to prevent infection from recurring.
If your veterinarian has diagnosed your cat with ringworm, he or she will explain what you must do to prevent the fungus from spreading to your other pets—and to the human members of the household. But keep in mind that if you have other pets, it’s likely that most of them have been exposed as well. Your veterinarian may recommend that you do the following:
- Bathe all pets in the household with a medicated rinse or shampoo.
- Wash the infected animals’ bedding and toys with a disinfectant that kills ringworm spores.
- Discard items that are impossible to thoroughly disinfect (carpeted cat trees, etc.)
- Frequently vacuum to rid the house of infected hairs and skin cells. (Yes, the fungus can survive on hair and skin that your cat sheds!)
- Thoroughly wash your hands after you bathe or touch your cat.
If a cat with ringworm is not properly treated, the lesions can spread over large areas of the animal’s body, causing hair loss and skin infections.