Part of the yearly wellness visit for a cat or dog includes sending a stool sample to the lab to test for intestinal parasites. On average, about one third of the samples we submit test positive for one or more parasites. Most dogs are on a monthly heartworm and parasite preventive, but these medications do not protect against giardia or coccidia, two parasites that are commonly spread by contaminated water, or tapeworms, which are spread by fleas. It’s not unusual for dogs and outdoor cats to have intestinal parasites. Indoor cats are less likely to have parasites, but from time to time we do receive a positive report from the laboratory.
How does an indoor cat become infected? There are several possibilities.
- Sharing a water bowl in a household with one or more dogs.
- Standing water on decks or patios. Many indoor cats spend a small amount of time being supervised outdoors, where they have access to potentially contaminated water or exposure to rodents and birds.
- Houseplants. 15% of commercial potting soil contains roundworm eggs. Cats that dig in houseplants can be exposed.
- Bugs! Crickets, cockroaches, flies and other insects can carry roundworms. Cats are natural hunters and frequently capture and eat bugs that get into your house.
- Rodents. Cats that catch and eat rodents in the house can become infected with roundworms.
Since many pets carrying parasites have no symptoms, it’s important to test yearly. Many parasites can be passed throughout the family undetected, including to humans.