By Carol McCarthy
If you have a cat, the odds are she will get intestinal worms at some point in her life. In fact, the Cornell University College of Veterinary Medicine reports that 45 percent of cats have an intestinal parasite at any given time. “It’s more unusual to have a cat not exposed to them,” says Dr. Cathy Lund of City Kitty, a feline-specific veterinary practice in Providence, RI. “They’re everywhere.”
Fortunately, your veterinarian can treat worms in cats effectively and safely, with no need for panic on your part, said Dr. Bruce Kornreich, associate director of the Feline Health Center at the Cornell University College of Veterinary Medicine in Ithaca, NY. So put those nightmare visions of worms feeding on your kitty out of your head and read on to learn how to protect your pet.
How Do Cats Get Worms?
Infestation depends on the type of worm, but most often, cats get worms by coming into contact with eggs or infected particles in feces. “They step in the feces and then ingest them when grooming themselves,” Lund said.
In some cases, outdoor cats will hunt rodents that have worm larvae living in their tissues. The cat then eats the rodent, ingesting the infected tissue, and the worm larvae grow into worms in the cat’s intestines, Kornreich said. Cats also can become infected by eating fleas that carry worm eggs or by being bitten by worm larvae penetrating the skin. Kittens can also get some types of roundworms when nursing from an infected mother, he added.
Roundworms are the most common intestinal worm in cats, representing 25 to 75 percent of infestations among the 80 million cats living in the United States, Kornreich said. Cats most commonly get roundworms by eating infected rodents or by ingesting feces containing roundworm eggs.
Roundworms grow to be between three and five inches long and eat the food your cat ingests, stealing her nutrients. The worms then produce eggs, which the cat eliminates in her feces (and can then infect other cats). The eggs can take weeks to become infective, so a cat owner who is fastidious with litter box hygiene can keep them at bay, Kornreich said.
What Other Types of Worms Can Cats Get?
Cats can get infected by tapeworms, hookworms and whipworms. They get tapeworms by ingesting fleas infected with tapeworm eggs or by eating infected rodents. “The entire worm matures in the large intestine of the cat,” Lund said. “[Then] pieces of the worm break off and are pooped out.”
The egg-filled tapeworm pieces that are shed in feces look like grains of rice or sesame seeds, are about a quarter inch long and, in some cases, are passed intermittently, so the owner might not see them, Kornreich said. Additionally, if your cat has tapeworms, they might also have fleas, he said.
Hookworms are small, half-inch long threads that can be hard to spot in cat feces. They feed on your cat’s blood, attaching to the lining of the intestines, Kornreich said. Adult cats get infected by hookworm larvae penetrating through their skin or by ingesting them. The larvae first migrate to the lungs and then the intestines where they grow into adult worms, infecting 10 to 60 percent of the cat population, he said.
Cats can also get whipworms, but this is rare in North America, Kornreich said. These worms reside in the large intestine, but don’t usually cause serious disease.
A cat that has intestinal worms may suffer from diarrhea, loss of appetite or vomiting, with the severity of symptoms dependent on the type of worm and how heavy the infestation is. Tapeworms and whipworms typically cause mild symptoms, both experts say, adding that severe infestations with roundworms and hookworms can make your cat seriously ill and may even cause anemia depending on how badly your cat is infested.
How are Kittens Affected by Worms?
According to Lund, because kittens are so small, they can become very ill as a result of a roundworm infestation, and are more vulnerable to becoming anemic from blood loss than adult cats.
“Because [kittens] are growing, they can’t afford to lose nutrition or the electrolytes to diarrhea. Their immune system is also not as developed, so they are at higher risk of other intestinal infections that may occur secondarily,” Kornreich said.
Pet parents might notice intense diarrhea, blood in the stool, vomiting and weight loss— both from not eating or from the parasite competing for food in the intestine — in kittens that have intestinal worms, Lund said.
How are Worms in Cats Diagnosed and Treated?
Your vet can usually diagnose worms with a physical exam, examination of a stool sample under a microscope, or by sending a stool sample to a laboratory for complete testing. Your vet also might order blood tests to get a complete picture of your cat’s health.
If your vet determines that your cat has worms, they will usually treat her even if she doesn’t have symptoms, Kornreich said. A variety of safe and very effective medications are available, with specific medications intended for specific infestations, and some medications work on several types of worms.
Medications are typically given by mouth at intervals that depend upon the type of worm, degree of infestation and results of follow-up fecal examinations. For example, a kitten might be treated for roundworms once a day for three days, with repeated dosing three weeks later and then perhaps three months later.
Regimens are designed to attack the worms at different points in their lifecycles, Lund said. Many of these drugs are safe to use even in very young kittens, she said, adding that the Companion Animal Parasite Council recommends prophylactic deworming of puppies and kittens starting at two weeks of age.
Your vet will repeat the fecal exam to ensure that the worms have been eradicated. However, re-infestation is not uncommon, especially in multiple-cat households or in cats that go outside, Kornreich said. Both experts caution against trying home remedies, which are not proven effective.
How Can I Prevent My Cat from Getting Worms?
“The biggest thing is to be proactive, getting a fecal exam and physical exam and being fastidious with the litter box. Clean and change it frequently,” Kornreich said.
You can also protect your cat by adhering strictly to a year-round regimen of flea prevention, whether through oral doses, topical applications or collars. This will help prevent and get rid of fleas, which can cause worms to begin with. Finally, keep your cat indoors where it cannot hunt and eat infected rodents.
In very rare cases, some worms can sicken people. Roundworm larvae, for example, can migrate to the skin or eye of humans, Kornreich said. When treating your cat or kitten for worms, “use common sense. Clean up feces quickly, wash your hands and wear gloves when cleaning the litter box,” he added. Wear gloves when gardening, too, as outdoor cats might use your garden as a litter box.
For an interactive map on parasite infestations in your state, as well as the latest treatments and news about pet parasites, visit the Companion Animal Parasite Council’s website.
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