Whipworms are an extremely common intestinal parasite of dogs.Whipworms live in the large intestine, and unlike many of the other intestinal parasites, are more common in adult dogs rather than puppies.Another difference is that whipworms only infect dogs in the U.S. It is estimated that 15% of dogs across the country are affected by whipworms.

Whipworms are important to diagnose because they can cause serious illness in dogs that are infected. The parasites feed off the blood of the large intestine, leading to diarrhea with mucus and blood, weight loss, unthriftiness, and eventually anemia. Sometimes the anemia can be severe, and the infected dogs can become significantly ill.

Whipworms are transmitted in the feces of an infected dog as eggs. The eggs can survive in the soil for months or years waiting to be ingested by another dog, and then complete the worms’ life cycle. It usually takes three months for a dog to show signs of infection, or for an infection to be picked up on a fecal test.

Whipworms are treated with a 3-day course of deworming medication that is repeated three weeks later. Interceptor and Sentinel, two types of heartworm preventive, can help to control whipworm infections, but cannot eliminate an infection that is already present.