Whipworms in Dogs: Symptoms, Treatment and Prevention

Whipworms are tiny parasitic worms that can latch onto a dog’s intestinal wall, causing inflammation, bleeding and diarrhea. While this parasite sometimes goes unnoticed, it can cause health issues if left untreated. Understanding whipworms in dogs, including how they spread, what to look for and how to help prevent infection, can help you take steps to protect your pup and other dogs in your community.

What Are Whipworms in Dogs?

Whipworms are intestinal parasites that live in a dog’s large intestine. The parasites are named for their whip-like shape, with a slender front portion (the “lash” end) and thicker back portion (the “handle” end). Whipworms attach to the intestinal lining and feed on blood, fluid and tissue.

Although only a few centimeters long, whipworms can cause health issues in affected dogs, especially when they are present in large numbers. The parasite can infect dogs of any age, but is more commonly diagnosed in adults because of the prolonged period between infection and a positive test result.

Types

There is only one known species of whipworm that affects dogs in North America, including wild dogs, such as foxes and coyotes. Trichuris vulpis does not infect other animals outside of the canine family, which means the parasite is not a danger to other pets or people living in a household with dogs.¹

How Dogs Get Whipworms

Whipworm eggs are passed in the feces of infected dogs and can survive in the right conditions for months or even years. Dogs become infected with whipworms by ingesting eggs from the environment.

Dogs can ingest eggs when they sniff, lick or eat feces or something that has come into contact with contaminated soil. Because whipworm eggs can remain infective for a long time, dogs who return to a contaminated environment after treatment can become reinfected.

Unlike some parasitic worms, whipworms are not passed from mothers to puppies during pregnancy or nursing. Dogs also cannot become infected by eating small prey, such as rodents or birds.

Not all infected dogs show symptoms, but asymptomatic dogs can still shed whipworm eggs and infect others. It takes a few weeks for eggs passed in the feces to mature to a stage that can infect other pets, so cleaning up feces right away can help prevent environmental contamination.

Common Symptoms of Whipworms

Whipworms can affect dogs in different ways, depending on how many worms a dog has and the dog’s overall health. Some dogs show no signs at all, while others — usually those with heavier infestations — may develop intestinal inflammation that leads to digestive problems. Pets with severe infections can, in rare cases, die from the infection.

When symptoms occur, they may come and go and may overlap with other digestive issues. Symptoms may include:

• Blood or mucous in the stool
• Chronic or intermittent diarrhea
• Dehydration
• Lethargy
• Weight loss

Diagnosing Whipworms in Dogs

Your veterinarian may recommend specific diagnostic tests if they suspect your dog has whipworms or other parasites. They might also detect whipworms on a routine fecal exam, which is recommended as part of a dog’s annual wellness care.

Detecting whipworm eggs in feces is more difficult than detecting other parasites because the worms may lay eggs intermittently. It can also take several months from the time of infection for the worms to begin shedding eggs. Your vet may recommend running multiple tests or repeating fecal tests periodically to increase the chance of detecting an infection.

Tests to detect whipworms may include:

• Antigen testing. Antigen tests detect proteins in the feces that indicate the presence of whipworms. This test is more sensitive because it can detect whipworms that aren’t actively laying eggs.
• Centrifugal flotation. A stool sample is mixed with a special solution and spun at a high speed in a centrifuge, causing parasite eggs to float to the top. The eggs are then examined under a microscope.
• Polymerase chain reaction (PCR) testing. PCR testing detects the presence of whipworm DNA. Similar to antigen testing, it can detect an infection without eggs.

Your veterinarian will choose tests based on your pet’s symptoms, age, lifestyle and test availability. Fecal floatation is widely available, but antigen and PCR testing are offered only by outside reference laboratories.

Treating Whipworms in Dogs

Veterinarians treat whipworms in dogs with specific deworming medications that are effective against whipworms. Since different deworming medications are used for different parasites, screening tests and a proper diagnosis are essential.

Deworming medications for whipworms are usually administered repeatedly over several months. This is because the dewormer kills adult worms in the large intestine but may not affect developing larvae or eggs. Repeated doses are necessary to kill several rounds of adults before they can lay eggs and continue the infection. 

Most of the time, vets treat dogs for whipworms only after detecting the worms on a fecal test. In some cases, veterinarians may prescribe deworming medication to pets who are experiencing chronic gastrointestinal (GI) problems, even if fecal tests are negative. This helps them definitively rule out parasites as a possible cause.

Preventing Whipworms in Dogs

Dogs with whipworms may not show obvious signs, making it easy for them to contaminate the environment — including their own backyard. Because whipworm eggs can survive for months to years, prevention is key to avoiding infection or reinfection. 

You can help protect your dog and others in your community by:

• Bringing a stool sample to your veterinarian at least twice a year for routine parasite screening
• Picking up and disposing of fecal waste immediately
• Seeking veterinary care and avoiding public spaces if your dog has diarrhea

Many monthly heartworm preventives contain ingredients that control roundworms and hookworms, but only a few also control whipworms. If your pet tests positive for whipworms or frequents potentially contaminated environments, your vet may recommend switching to one of these specific monthly parasite prevention products.

Whipworms and Your Dog

Whipworms may be small, but they can cause big problems for your dog’s health. Fortunately, routine parasite prevention, regular fecal exams and quick cleanup of pet waste can help protect your furry pal’s health and well-being. Following guidance from your vet and practicing these simple habits can help you keep your dog free of whipworms and feeling their best every day.

Frequently Asked Questions About Whipworms in Dogs

Still curious about whipworms in dogs? Here are the answers to some common questions that pet owners often ask.

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Author Bio

Angela Beal, D.V.M., has more than 20 years of experience as a veterinarian. Leveraging her background in private practice and academia, she uses her passion for writing to convey information to pet owners to help them keep their pets healthy and happy.