What is Whipworm and Why Should I Care?


What are whipworms?
Whipworms are an intestinal parasite that can occur in both dogs and cats; however, they are seldom seen in cats in North America. Whipworms are named for their characteristic whip-shaped body. The body is composed of a thin, filamentous, anterior end (the “lash” of the whip) and a thick posterior end (the “handle” of the whip). Adult worms are about 2-3 inches in length. The adult worms live primarily in the cecum (the equivalent of your appendix) where they insert their long, skinny ends into the lining of the intestine and feed on blood, other tissue fluids and the lining itself.

How common are whipworms?
According to the Companion Animal Parasite Council, canine whipworms occur not only in dogs but also in foxes and coyotes; in samples of dogs in the United States in shelters and at veterinary teaching hospitals, whipworms were found in almost 15% and 10% of dogs respectively. Keep in mind, though, that these results are based on the recovery and identification of eggs requiring specific preparation of the stool sample. Consider that eggs are not always shed and eggs are not shed immediately upon infection or even maturity of the adult worm. You can see that many infections may actually be missed meaning that true infection rates may be higher.

How does my dog get whipworms?
Unlike some other common intestinal parasites in dogs, whipworms cannot be transmitted via other species/hosts or between mother and offspring before birth or during nursing. Infection does not require direct contact with another dog. Whipworm infections only occur when a dog eats infective stage eggs from the environment. However, that means it can happen anytime your dog inadvertently ingests soil that has been contaminated with whipworms eggs, for instance, eating grass, rooting in the dirt, or playing with toys that have been in contact with soil. In addition, wild canines like foxes and coyotes can carry whipworms. Once deposited these whipworm eggs can survive in the environment for years. All of this put together means that the risk of infection to your dog can be significant.

What are the symptoms of whipworms?
Some dogs show no symptoms at all of being infected with the worms but still serve as a source of contamination in the environment and infection for other pets. Clinical cases may be accompanied by the following symptoms:

  • Diarrhea with or without mucus or obvious blood
  • Dehydration as a result of diarrhea
  • Gastrointestinal bleeding (if chronic or severe, this can cause anemia and dogs can become debilitated and seriously ill)

Diagnosing and treating whipworm
As mentioned above, the definitive test is to find whipworm eggs with a test of your dog’s stool sample. This test needs to be performed correctly and on a relatively fresh sample. Sometimes your veterinarian will make a presumptive diagnosis of whipworms, even in the face of a negative stool sample test, based on clinical symptoms and response to appropriate therapy.

Please note that most de-worming medications that are available over the counter are not effective at killing whipworms. Your veterinarian needs to provide you with the right medications to clear a whipworm infection.

Can I get whipworms from my dog?
No, you cannot. People sometimes confuse whipworms with the pinworms children get. They are not the same thing.

How do I prevent whipworms?
Given the fact that whipworm eggs survive for so long in the environment, in areas where whipworms occur, all dogs are at risk of infection and previously infected dogs continue to be at risk for re-infection. Always clean up after your dog to remove feces from the environment before any eggs can become infective. Talk to your veterinarian about maintaining your dog on a monthly treatment all year round to control whipworm infections, and have your dog’s stool sample checked yearly as part of his/her routine wellness examination.

If you have any questions or concerns, you should always visit or call your veterinarian -- they are your best resource to ensure the health and well-being of your pets.

Reviewed by:

Bill Saxon DVM, DACVIM, DACVECC


Ask The Vet - Dr. Anne Pierce, DVM

A sign has recently appeared at a local park that warns visitors that whipworm contamination has been determined to be a problem there. In spite of the fact that the sign is present in only one place, it really could be applicable to any location where lots of dogs congregate, so it is worth knowing something about whipworms in general if you take your dog out in public at all.

We do not diagnose whipworms commonly in this area. The infective eggs are pretty tough and can live in the soil for years, even withstanding freezing weather, but like the little vampires they are, they don’t like direct sunlight and dryness, of which we seem to have an ample supply in these parts. As a result, they tend to be a much more common problem in warm, humid parts of the country like the southeast.

A dog gets whipworms when it ingests the eggs that have been deposited in the soil in the feces of a previously infected dog. The eggs have to go through a one month development period after being deposited in the soil before they are ready to infect another animal, so contact with fresh stool doesn’t run the same risk of infection. Once a mature whipworm egg is ingested, say as a result of licking dirt with eggs mixed in off of feet, it takes about three months for the immature whipworm to develop into a mature worm that burrows aggressively into the lining of the large intestine and sustains itself on the blood of the host. That burrowing can cause quite a bit of irritation which sometimes manifests as intermittent, possibly bloody diarrhea if the number of worms is large enough. The signs are more often minimal to non-existent when only a few worms are present. Weight loss and anemia are technically possible too, but it would require an extraordinarily large infestation to cause those types of problems, and it would be very unusual to see those sorts of cases in this area.

Diagnosing whipworms can be tricky. We look for the microscopic eggs in stool samples, but those shifty worms tend to release eggs intermittently, and in lower numbers that many other types of intestinal parasites, so it is possible to look at a stool sample from an infected animal and not see the eggs. Sometimes multiple samples need to be evaluated.

Treating whipworms can sometimes be tricky too. Most over the counter dewormers contain pyrantel pamoate, which is very effective against common roundworms, but will have absolutely no effect on whipworms. Your veterinarian, however, has effective products for killing whipworms. In order to completely clear the infestation a dog usually needs to be treated several times about 3 weeks apart because the medication kills adult worms but leaves the developing juveniles behind. After the first dose we wait for the leftover youngsters to mature to adults and then zap them with another dose when they become susceptible.

Reinfection from a contaminated environment can be significant problem. Picking up stool daily helps remove recently shed eggs before they can reinfect a dog, but for the eggs already in the environment there is nothing to do besides wait them out. Pouring bleach all over the ground just ruins your yard, puts poison into the environment, and causes infective whipworm eggs to giggle amongst themselves at the ineffectiveness of your efforts.

People get whipworms too, especially hot and humid parts of the world. The whipworms that affect people, however, are a different species than the type that gets into dogs, so there is no significant risk that dog whipworms will cross the species line and affect people too, although the same cannot necessarily be said of other types of intestinal parasites, so just to be safe it would be best not to eat dog poop or dirt that could be contaminated.


Causes of Whipworms in Cats

Whipworm in cats is caused by the ingestion of water, food or flesh (mice, birds, etc.) contaminated with adult whipworms, whipworm larva, or eggs.

To understand how a cat may become infected with whipworms, an individual must understand the lifecycle and nature of these parasitic worms. Whipworms latch on to the mucosa layer of the cecum or colon of the cat, feeding and laying eggs. These thick-shelled, weather resistant eggs, are passed through the feces, enter the soil and become active to infest within one to two weeks. If your cat drinks water from an outside source or even licks her paws after being outside, she could pick up one of the 2,000 whipworm eggs a female can lay in a day. A feline can also infect herself with whipworms upon consumption of prey animals such as rodents, birds, and other appealing prey.


What is Whipworm and Why Should I Care? - pets

What are whipworms?

Whipworms are intestinal parasites that are about 1/4 inch (6 mm) long. They live in the cecum and colon (large intestine) of dogs where they cause severe irritation to the lining of those organs. Whipworm infection results in watery, bloody diarrhea, weight loss, and general debilitation. They are one of the most pathogenic worms found in dogs.

How do dogs get whipworms?

Whipworms pass microscopic eggs in the stool. The eggs are very resistant to drying and heat, so they can remain viable (alive) in the environment for up to 5 years. Once laid, they embryonate (mature to an infective stage) in the environment and are able to re-infect the dog in 10-60 days. The embryonated eggs are swallowed and hatch and mature to adults in the lower intestinal tract, completing their life cycle (see illustration).

How are whipworms diagnosed?

Whipworms are diagnosed by finding eggs with a microscopic examination of the stool. However, multiple stool samples are often required because these parasites pass small numbers of eggs on an irregular basis, so some samples may be falsely negative. In addition, it takes approximately 11-12 weeks after hatching for a female adult to begin to lay eggs. Any dog with chronic large bowel diarrhea should be suspected to have whipworms, even if the stool sample was negative. Thus, it is an accepted practice to treat chronic diarrhea by administering a whipworm dewormer. Response to treatment is an indication that whipworms were present but could not be detected on fecal examination.


How are whipworms treated?

There are several drugs that are very effective against whipworms. At least two treatments are needed, spaced at a three to four week interval. The most frustrating aspect of whipworm infections is the high rate of re-infection because the eggs are extremely hardy in the environment. Therefore, if a dog is diagnosed with a whipworm infection, it is advisable to treat again every three to four months. The other option, which is much simpler, is to use a heartworm preventative that contains a whipworm medication. Whipworms are not nearly as common today because of widespread use of these modern heartworm prevention products.

Can I get whipworms from my dog?

No. Whipworms are not infectious to people. They are exclusive parasites of the dog.

This client information sheet is based on material written by: Ernest Ward, DVM © Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license.


Whipworms in Pets: Protecting Your Pet Against Intestinal Parasites

Some intestinal parasites are easier to get rid of than others, and perhaps none is quite as formidable as the dreaded whipworm. A relatively common parasite of the dog (as well as coyotes and foxes), the whipworm, or Trichuris vulpis, can be hard to get rid of.

What’s a whipworm

The dreaded whipworm is a small worm, averaging under a centimeter in length. They feature a long, skinny whip-like tail (hence their name). Because they live in the cecum, (where the small and large intestines join.), most times pet owners never see the worms in the stool. They whipworm attaches to the tissue of the intestine in this location and feed on the blood within the intestinal wall. They lay eggs here as well, which then pass into the stool, contaminating the soil surrounding the feces. In 2 to 4 weeks, these eggs in the environment are capable of infecting a new host.

How pets get infected

Because the whipworm eggs are hiding in the dirt and surrounding environment, a dog will often become infected while grooming itself. Once a pet is infected, the whipworm egg gets to work hatching and heading to the cecum to make its new home. This process takes about a week. A few whipworms are no big deal, however a large infestation can result in diarrhea, blood loss, or periodic weakness characterized by electrolyte imbalance.

So why are whipworms such a pain in the rear? (Pun intended). Firstly, female whipworms do not lay eggs constantly, so unless fecal samples are examined multiple times, infestation may be missed. Also, young whipworms take 2-3 months to mature and be susceptible to traditional deworming. This means that multiple dewormings must take place to entirely eradicate an infection. Finally, whipworm eggs are quite hearty. Once they contaminate the soil in an area, it is virtually impossible to get rid of them. The environment may be contaminated for years, making repeat infestation highly likely.

What to do

So what can we do? Thankfully, we do have dewormers that are quite effective. If whipworm infestation is diagnosed (or suspected), pets are prescribed a deworming medication such as fenbendazole or febantel. Doses are often repeated in a few months. Because of the high likelihood of repeated exposure, pets that have whipworms also often benefit from remaining on a monthly parasite preventative that provides whipworm protection. There are several heartworm prevention products that also provide this benefit. Whipworms are tricky little worms, but with a little knowledge it is possible to control them in our pets.


Watch the video: Trichuris Trichiura, or Whipworm


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