Feline Whipworm Infection

What are whipworms?

Whipworms are intestinal parasites, about 1/4-inch long, that live in the cecum and colon of the cat. There they cause severe irritation to the lining of those organs, resulting in watery, bloody diarrhea, weight loss, and general debilitation. Whipworms are among the most pathogenic (harmful) worms found in cats, though feline infection is quite rare in our area — considerably rarer than in dogs.

How did my cat get whipworms?

The cycle starts and ends in contaminated soil:

1. An infected animal passes microscopic eggs in its stool.
2. The eggs mature in soil and become infective within 10 to 60 days.
3. A cat swallows the eggs — most often while grooming soil or litter dust off its coat and paws.
4. The larvae settle into the lower intestinal tract, mature, and begin producing eggs of their own.

The eggs are highly resistant to drying and heat and can remain viable in the environment for years. Outdoor cats, and cats with access to gardens or uncovered sandboxes where wildlife pass through, face the most exposure; strictly indoor cats rarely encounter whipworms at all.

How is whipworm infection diagnosed?

Whipworms are diagnosed by microscopic examination of the stool, but they are easy to miss: females pass small numbers of eggs on an irregular schedule, so a single negative sample proves little, and multiple samples are often required.

Because of this, a cat with chronic or recurring diarrhea can reasonably be suspected of having whipworms even after several negative stool examinations. It is accepted practice to treat on the assumption of infection — a good response to treatment is itself evidence that whipworms were present but escaping detection.

How are whipworms treated?

Several effective drugs are available. Two treatments are needed at a three- to four-week interval and, because environmental reinfection is such a problem, retreating every three to four months is advisable for cats that keep going outside. Alternatively, after the initial treatment, a monthly parasite prevention product that covers whipworms handles the problem quietly in the background — widespread use of these products is a big part of why whipworms have become uncommon.

Scooping the litter box daily and keeping it clean also limits the chance of eggs maturing anywhere your cat grooms.

Can I get whipworms from my cat?

No. Feline whipworms are not infectious to people. If you have multiple cats — or a dog — sharing the same outdoor space, though, it's sensible to have stool checks run on the housemates as well.

See Canine Whipworm Infection