Frequently Asked Question (FAQ)

Should I deworm my pet?

According to the Companion Animal Parasite Council and the Center for Disease Control (CDC), all pets should have their stool tested at least once a year and be on a routine deworming program. Test a fecal sample from your pet and set up a deworming program with your veterinarian as soon as possible and especially after obtaining a new puppy or kitten. For more information visit

Roundworms and hookworms are examples of common intestinal parasites in cats and dogs that have the potential to make people sick (zoonosis). Pets infested with these parasites will shed microscopic eggs in their stool, contaminating the environment. A person unknowingly ingesting roundworm eggs can develop visceral larval migrans (VLM). VLM occurs when the parasites end up in the "wrong" host (i.e. people). Instead of living in the intestine (as in a dog or cat), they get "lost" and migrate to other organs, potentially causing serious diseases such as blindness. Hookworm larva, which tend to live in grass and sand areas, can invade and migrate through human skin. Children and people with reduced immune function are most susceptible, but recent studies have shown that 30% of all children test positive for exposure to intestinal parasites of pets. In addition, the microscopic eggs have been shown to survive for six years in the soil.

Year round deworming will help ensure that any parasites picked up by our pets are eliminated on a monthly basis. Thus, keeping our pets clean and not adding to further contamination of the environment which risks the health of our children.

For cats, in particular outdoor cats, monthly deworming is very important. These cats are using playground sandboxes and gardens to eliminate in. It only takes 3 weeks from ingestion of a mouse until the cats begin shedding the microscopic eggs in their stool. Monthly deworming is key to keeping our cats and, therefore, our play areas clean.

For dogs, parasite control is simply an extension of the heartworm season. Some of the medications currently being used June through November to control heartworms are also very effective intestinal dewormers. We are, therefore, recommending year round use of heartworm medication for our canine patients. Please call and inquire which medication will meet your pets' specific needs.

In addition to being zoonotic, these and other intestinal parasites can cause life threatening illnesses for your pet. Hookworms and whips worms can cause massive blood loss through the intestines which can be fatal. Roundworms and tapeworms deprive your pet of nutritional components from their food.

Other intestinal parasites include organisms like protozoa (i.e. giardia and coccidia) and bacteria (i.e. e-coli). These organism can be spread by other pets and by wildlife to our companions. Some of these organisms can also be transferred to people. They usually cause chronic or reoccurring diarrhea. Special tests are needed to confirm this type of infection.

Most intestinal parasites are easily spread between pets by a "fecal-oral" route. This means the eggs are shed in the stool and then picked up by another pet orally. Direct pet contact is not required to pass these parasites along. Even though we all "stoop & scoop" after our pets, it is impossible to pick every microscopic particle up. Microscopic amounts left in the dirt or grass are then a source of spreading. Your pet simply needs to smell or step in this grass then lick his/her lips or paws in order to pick up the organism. In addition, these parasites are extremely hardy, meaning that they survive very well in the soil and cold weather. Microscopic amounts can also be unwittingly carried home by owners on their shoes. In this way, a pet that never leaves the home can also become infected.

Tapeworms are the exception to this type of transmission. They are carried by intermediate hosts which are either fleas or small rodents. When your pet catches mice or gets fleas, he/she is at risk for picking up a tapeworm infection.

Testing and deworming only identifies and kills, respectively, the adult stages of these parasites. Intestinal worms have inactive larval stages that can remain sequestered in the muscle for years. Any type of stress such as having puppies/kittens, another disease, moving etc. can cause the inactive stages to migrate and mature in the intestine. In this way a pet that has been tested negative and stayed indoors for years can suddenly appear to have a new infection.

Testing for intestinal parasites involves sending a sample of a fresh stool sample to a laboratory. Only roundworms and tapeworms can easily be seen with the naked eye. Even with these parasites, pets can have infections when no worms are visible in the stool. Special sample preparation techniques and microscopic examination are needed to accurately identify animals that are infected. All pets should be tested and preventative deworming program discussed with your veterinarian annually.

Finally, although diarrhea is one sign of intestinal parasites, keep in mind two important things:1) that an animal with intestinal parasites does not always have diarrhea and 2) intestinal parasites are only one of many causes of diarrhea in pets. Consult your veterinarian for guidance on these issues.