How Do Indoor Cats Get Roundworm?

Roundworms are, as the name suggests, round-bodied worms, 3 inches to 6 inches in length, that frequently infest cats and dogs. Veterinarian Eric Barchas says there's a good chance of infection if a cat hunts outside and eats prey that contains roundworm eggs, but even a cat that's completely housebound can become infected if conditions are right. Roundworm infestation is common, and can usually be successfully treated.

  1. Roundworms

    • Merrimack Veterinary Hospital says cats can be infected by the feline roundworm, Toxocara cati, and the less common Toxascaris leonina, technically known as ascarid worms. In addition to living in cats, the eggs can infect intermediate hosts such as insects or birds, and a hunting cat can become infected by eating them.

    Infecting Indoor Cats

    • There are several ways an indoor cat can become infected with roundworm. If a mother cat has roundworm, the eggs can be passed to kittens through the milk. House flies or cockroaches serving as intermediate hosts can bring the eggs inside; if a cat eats the insect, it eats the eggs too. If one of several cats is allowed out and becomes infected, the next generation of eggs will be passed out in its stool, where other cats or insects could pick them up by contact. Roundworms can potentially be transmitted to humans.

    Detecting Infestation

    • If a cat is infested with roundworm, the most common symptom is diarrhea; in kittens, it can be so severe as to dehydrate and kill them. Most cases are not that severe, and vets say a majority of kittens carry roundworms at some point. To diagnose roundworms, a small amount of cat stool is mixed with a special solution; if there are roundworm eggs in the stool, the vet will be able to identify them under the microscope. Sometimes a cat will also vomit up intact worms.

    Prevention

    • Keeping cats indoors does reduce the chances of their eating roundworm eggs, but doesn't guarantee it. One important step is to clean stool from the cat's litter boxes every day, or as regularly as possible. Always wash your hands after touching the litter box material. Have your house sprayed for insects regularly, and dispose of any rats, which can also be hosts.

    Deworming

    • Roundworm can usually be treated effectively and cost-effectively with the deworming drugs available on the marketplace. Merrimack recommends deworming adult females before breeding them to cut down on transmission to kittens; kittens should be dewormed regularly, even if they aren't showing symptoms.