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
- mucous or blood in stool
- anemia (pale gums, weakness) can be seen with chronic, heavy infections
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.
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.