Canine Whipworm Infection

Whipworms are intestinal parasites. They are about 1/4-inch long and live in the cecum and colon of the dog, where they cause severe irritation to the lining of those organs. This results in watery, bloody diarrhea, weight loss and general debilitation. Whipworms are one of the most pathogenic (harmful) worms found in dogs, but are quite rare in our area.

Whipworms pass microscopic eggs in the stool. These eggs are very resistant to drying and heat, so they can remain viable in the dog's environment for years. As they mature, they are able to reinfect the dog within 10 to 60 days. When the eggs are swallowed, they return to the lower intestinal tract to complete the life cycle.

Whipworms are diagnosed with a microscopic examination of the stool. However, multiple samples are often required because these parasites pass small numbers of eggs on an irregular basis. Any dog with chronic diarrhea can be reasonably suspected to have whipworms, regardless of several negative stool examinations. Because of this, it is an accepted practice to treat for whipworms based on assumption of infection. Response to treatment is an indication that whipworms were present but could not be detected on fecal examination.

There are several effective drugs available to treat whipworms. Two treatments are needed at a three- to four-week interval, but because reinfection is such a problem, it is advisable to treat again every three to four months. Alternatively, you may put your dog on a heartworm prevention product that defends against whipworms after the initial treatment. Whipworms are not nearly as common now because of widespread use of these types of products.

No. Whipworms are not infectious to people.