The canine whipworm, Trichuris vulpis, is considered to be one of the “big four” parasites that threaten dogs. The yearly fecal test submitted to the laboratory (or any time your pet has diarrhea or other intestinal symptoms that suggest parasites) screens for roundworms, hookworms, roundworms, and whipworms.
The canine whipworm is a helminth parasite from the roundworm family. Its name comes from the shape of the parasite itself, which is whip-like with a wider section at one end. The whipworm is much smaller than most other worms, reaching a maximum length of about two inches, and is rarely seen because it lives in the cecum, the part of the intestinal tract where the large and small intestine meet.
A dog is infected with whipworms when he comes in contact with contaminated soil and swallows eggs, usually through normal grooming. The egg hatches in the small intestine and the resultant larva burrows into glandular tissue. In about a week, the larva emerges back into the small intestine and is carried to the large intestine with digested food.
Adult whipworms embed their heads into the tissue of the intestine and suck blood. In approximately three months, the adult whipworm is ready to mate. Eggs are laid inside the large intestine and pass out of the body along with stool. Eggs require two to four weeks to mature enough to be infective once outside the host’s body.
A mild whipworm infection usually produces no symptoms, but if large amounts of adult worms embed in the tissue of the large intestine, a patient may have generalized abdominal pain (from the inflammation) and bloody, sticky diarrhea. Blood loss from whipworms is generally small, but the chronic nature of such a symptom can lead to dehydration and secondary conditions, so thorough deworming is a necessity when whipworm infection is suspected or confirmed.
Whipworms are diagnosed with a fecal flotation test, which looks for evidence of eggs. However, female whipworms do not continuously lay eggs, meaning a pet can have a heavy whipworm infection but still yield a negative stool sample. Young whipworms take a long time to mature, so a second deworming is needed to fully remove the infection.
Once soil is contaminated with whipworm eggs, it is virtually impossible to remove the eggs from the soil or kill them. The best course of action is to pick up stool immediately and dispose of it. Prevention is also possible by giving a monthly heartworm/intestinal parasite preventive, such as Sentinel.