Whipworms

Whipworms (Trichuris vulpis, Trichuris campanula) are common in dogs and found throughout the United States. Trichuris serrata may rarely be found in cats. Whipworms get their name from the whip-like shape of the adult worms. The front portion of the worm is very thin (the whip) and the posterior end is thick (whip handle). Whipworms live in the large intestine and cecum (a small ‘dead-end’ portion of intestine lying at the junction of the small intestine and large intestine).

How are whipworms transmitted and how is whipworm infection diagnosed?

A dog or cat becomes infected by ingesting food or water contaminated with whipworm eggs. The eggs are swallowed, hatch, and in a little less than three months, the larvae mature into adults in the cecum and large intestine where they burrow their mouths into the intestinal wall and feed on blood. Adult worms lay eggs that are passed in the feces. The eggs must remain in the soil for about a month to mature and be capable of causing infection.

An infection is diagnosed by finding the eggs in the feces. The eggs must be differentiated from those of the bladder worm (Capillaria plica, Capillaria felis cati) and C. aerophilia, a parasite of the respiratory system, but whose eggs may be found in the feces. The female worms do not produce eggs every day, and the egg numbers are usually small, so repeat fecal exams may be necessary to find the eggs.