There are several types of intestinal parasites that cause problems in dogs and cats. These include roundworms, tapeworms, hookworms, whipworms, and giardia. Parasite eggs and giardia cannot be seen with the human eye.


If a growing puppy or kitty is infected with a large number of roundworms, the worms can stunt their growth, cause serious digestive upset, and result in excessive gas formation. These little ones often have a characteristic ‘pot-bellied’ appearance. Roundworms can be transmitted by ingestion of eggs that are shed in the feces of infected dogs and cats.


Hookworms are one of the most significant intestinal parasites of the dog. The hookworm is approximately ½ to 1″ (1-2 cm) long and attaches to the lining of the small intestines, where it feeds on blood. As a result of this blood-sucking, hookworms can cause severe anemia. The infective larvae enter the pet either by mouth or through the skin, particularly the feet. Eczema and secondary bacterial infection can result due to irritation as they burrow through the skin.


Whipworms are small worms, usually only ¼” (6 mm) long. They live in the large intestine, where they cause irritation and inflammation. Symptoms of whipworm infection include chronic watery diarrhea, bloody diarrhea, and weight loss. Whipworms can be transmitted by ingestion of eggs that are shed in the feces of infected dogs and cats or from the soil. Whipworms can live in the soil for years.


Pets get tapeworms most commonly by ingesting a flea, a bird, or certain species of rodent. Your pet cannot get tapeworms directly from another dog or a cat. However, there is a species of tape worm named Echinococcus that is important because it is zoonotic, meaning humans can be infected. The adult tapeworm is tiny, only about ¼” (5-6 mm) long. This worm develops inside cysts in various organs of sheep, and humans. In humans, these cysts can involve the lungs or brain.


Giardia is a single-celled microscopic parasite that attaches itself to the small intestines of dogs, cats, and humans. It must be ingested by your pet to get the parasite. Examples are eating grass, chewing on a stick, eating contaminated feces, or drinking from contaminated water. Giardia is zoonotic, meaning humans can be infected.

What can you do?

  • Practice good hygiene
  • Make sure your pet is on flea prevention
  • Make sure your pet is on heartworm prevention. Most of these have intestinal parasite de-wormer in them.
  • Clean up feces
  • Have your veterinarian check a fecal every 6 months to ensure an infection hasn’t started.
    • Pets don’t always show symptoms of infections right away. Your vet can check for eggs prior to them growing into an adult.
  • Once worms are detected, treatment should start right away.
    • There isn’t just one de-wormer that kills all intestinal parasites.