The adult whipworm is 2 to 3 inches (50 to 76 mm) long. It is threadlike for
the most part, but is thicker at one end, which gives it the appearance of a
The adult worm lives in the last part of the small intestines and the first
part of the large intestines, where it fastens to the wall of the gut. The
female lays fewer eggs than other worms, and there are long
periods during which eggs are not shed. Accordingly, finding eggs in the feces
is difficult, even with repeated stool examinations.
Whipworms can cause acute, chronic, or intermittent diarrhea in dogs. Typically, the stool is
mucoid and bloody. The diarrhea is often accompanied by urgency and straining
(see Colitis). Dogs with a heavy infestation may lose
weight, fail to thrive, and develop anemia.
Treatment: A number of preparations are effective against whipworms. They
include Panacur, Drontal Plus, Telmintic, and Vercom Paste. However, it is
difficult to attain high drug concentrations in the colon, where the whipworms
reside, and this makes them difficult to eradicate. To maximize success, follow
up the initial deworming with a second deworming three weeks later and
a third deworming in three months.
Prevention: Eggs remain infective in the environment for up to five years.
In areas such as public parks and backyards, where the ground has been heavily
contaminated with whipworm eggs, frequent reinfection is a common problem. It
is important to observe pooper-scooper ordinances and remove stools in the yard
every day. Dirt runs should be relocated and paved with concrete or new gravel.
Use household bleach in a 1:32 dilution to disinfect concrete and gravel runs.
It may be necessary to totally change the gravel in gravel runs.
The drug Interceptor, given to prevent heartworms, also controls and prevents whipworms.
Threadworms are round worms just 2 mm long that live in the small intestines
and infect both dogs and humans. The parasite is found in humid, subtropical
regions such as the southeastern United States and Gulf Coast areas.
The life cycle of the threadworm is complex. Eggs and larvae are passed in
the feces. Larvae become infective and are either ingested or gain entrance by
directly penetrating the skin.
Threadworms are mainly a problem in puppies. Infected pups suffer from a
profuse watery or bloody diarrhea that can be fatal. Pneumonia may occur as the larvae migrate through the
Treatment: The diagnosis is made by finding eggs or larvae on microscopic
examination of stool, both fresh and after incubation. A five-day course of
Panacur is the treatment of choice. Retreatment in 30 days is recommended. Ivermectin has also been used effectively, although it
is not labeled for this purpose.
Public health considerations: Dogs can readily infect humans, and vice
versa. Threadworm infection in humans is a debilitating disease accompanied by
chronic diarrhea. Accordingly, infected pups must be isolated until treated and
cured. Extreme care must be taken to avoid human contact with the feces of dogs
infected with threadworms.