Recognizing the Symptoms of Whipworms Can Be Tricky

Most dogs can cope with a light worm burden without showing any symptoms.

By: AllieKF
Most dogs can cope with a light worm burden without symptoms. By: AllieKF

“Whipworm” is the common name for the nematode worm Trichuris vulpis.

Although whipworms can survive in most climates, what really makes them feel at home is warm, damp environments, and so the dream location for any aspirational whipworm is a tropical or subtropical climate.

Their intended host is the dog, and the life cycle involves worm eggs in the soil coming into contact with dogs. For some reason, the peak age for infection is 12 to 18 months, and kenneled dogs with access to soil runs are the most likely to pick up infection.


Most dogs can cope with a light worm burden without showing any symptoms. A mild infection can cause intermittent, waxing and waning diarrhea that alternates with normal stools.

With a heavy infection, the worms create significant irritation to the lining of the bowel, which responds by becoming inflamed. The dogs then show symptoms including weight loss and blood-tinged diarrhea.


With its short, stumpy body and long, curling tail, it’s easy to see why Trichuris vulpis has acquired the nickname “whipworm.”

When straightened out, it measures around 4 to 7 cm and is creamy-white in color. The female whipworm, in common with many successful parasites, including fleas, has a huge potential to reproduce and can produce 2,000 eggs a day.

A whipworm life cycle involves eggs contaminating the soil, which dogs then come into contact with. The dog swallows the egg, which hatches in the bowel, and the worm then burrows its head deep into the top layers of the lining.

This creates inflammation, and the tunnels can also bleed. In an attempt to protect itself, the bowel may produce mucus as a bandage layer, and sometimes this mucus is seen on the stool.


Diagnosis is made by examining fecal samples to look for the presence of eggs or worms. However, worm eggs are not passed each time the dog has a bowel movement, so to avoid false negative results it is best to submit several samples.

The most common way of doing this is to put a sample from a bowel movement every day for 3 days into the same container (this is known as a “pooled” sample). This way, the chances of striking it lucky and finding eggs is much more likely.

When looked at under the microscope, whipworm eggs have a distinctive lemon shape with a tiny plug at each end.


Some of the medications used against heartworm, such as milbemycin, are effective against whipworms, and these worms are also sensitive to common anti-parasite treatments such as fenbendazole.

However, most drugs are ineffective against the immature, larval forms of whipworm, and if treatment is stopped too early only partial resolution is brought about. To avoid this, stool samples need to be monitored to ensure that treatment is 100% effective.


In a kennel situation, replace soil runs with concrete. Concrete lacks the humidity that whipworm eggs like, and in dry heat and sunlight the eggs dry out and die. Also, remove all feces promptly so they do not act as a source of contamination.


  • “Trichuris and other trichinelloid nematodes of dogs and cats in the United States.” Campbell. Comp Cont Ed Pract Vet, 13: 769–778.


This pet health content was written by a veterinarian.

Dr. Pippa Elliott, BVMS, MRCVS

View posts by Dr. Pippa Elliott, BVMS, MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty puggle called Poggle, 3 cats and a bearded dragon.

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