Whipworms in Dogs and Cats

Signs, Diagnosis and Treatment of Whipworms

Whipworm (Trichuris trichiura) of a dog in the institute for parasitology of the Ludwig-Maximilians-University Munich
Whipworm (Trichuris trichiura) of a dog in the institute for parasitology of the Ludwig-Maximilians-University Munich. Agency-Animal-Picture / Getty Images

About Whipworms

Whipworms are intestinal parasites that are relatively common in dogs but only occasionally seen in cats. The medical term for a whipworm infestation is "trichuriasis" — after the variety of Trichuris species that affect various host species.

Whipworms are small worms, reaching a maximum size of 2-3 inches. They have a thin, whip-like front end and a thicker back end. They attach themselves to the walls of the large intestine, feeding on blood.

Most infections are mild, especially in cats, but heavier whipworm infections can cause chronic health problems in dogs.

The Whipworm Life Cycle

Whipworms have a simple life cycle. Whipworm eggs are passed in the feces, and under ideal conditions, they become infective after about 2-4 weeks in the environment. The eggs are then ingested (e.g. during self-grooming, or eating things off the ground), and hatch in the small intestine.

Eventually, the larvae move to the large intestine, taking about 11 weeks to become mature and capable of producing more eggs which then pass to the environment. The eggs can survive for years in the environment. Whipworms are more common in older dogs than puppies.

Signs and Symptoms of Whipworms

In dogs with light infections, there are usually no symptoms. As infections get heavier, inflammation of the large intestine can result, and any of the following symptoms may appear:

  • Weight loss
  • Diarrhea
  • Mucus or blood in the stool
  • Anemia (pale gums, weakness) can be seen with chronic, heavy infections

Rarely, whipworm infections cause a syndrome similar to Addison's disease, with periodic episodes of weakness and electrolyte imbalance, though the mechanism of this effect is poorly understood.

Cats usually have light infections and lack symptoms.

Diagnosis of Whipworms

The eggs of whipworms can be detected under the microscope in a check of a stool sample (the test process is called fecal flotation). However, unlike roundworms and hookworms, female whipworms only produce eggs intermittently, so the eggs can be very difficult to catch on fecal tests. Repeated tests may be necessary, and if a whipworm infection is suspected it is common to treat for whipworms even if eggs aren't found.

Treating Whipworms

There are a number of medications that can be used to treat whipworms, and your vet can help you pick the one right for your dog (they are resistant to some common dewormers). Repeated treatments are usually recommended for best results (e.g., after 3 weeks and 3 months).

Because the eggs survive for so long, the potential for re-infections from eggs in the environment is significant. Your vet may recommend a monthly parasite preventative effective for whipworms to prevent whipworm infections on an ongoing basis.

Keeping pet wastes picked up promptly can help prevent infections with whipworms.

People and Dog Whipworms

There have been rare and controversial reports of people being infected with dog whipworms.

However, animal whipworms are not considered a significant human health risk (humans do have their very own species of whipworm, though).

Please note: This article has been provided for informational purposes only. If your pet is showing any signs of illness, please consult a veterinarian as quickly as possible.