Whipworms are a common intestinal parasite of dogs. They are the smallest of the worms that frequently infect dogs. The name whipworm comes from the shape.
- What are whipworms?
- How do whipworms spread and how do dogs get them?
- What are the symptoms of a whipworm infection?
- Diagnosis of whipworm infection
- Treatment of dogs with whipworms
- Prevention of whipworm infections
- Can humans get whipworms?
The dog whipworm is Trichuris vulpis. It is a small worm that is usually less than a ¼ inch long. Whipworms are very thin with a much thicker area at the tail, giving them a whip-like shape. The wider tail end is where the reproductive organs are located.
Unlike the other major parasitic worm of dogs (tapeworms, hookworms and roundworms) whipworms are found not found in the small intestine. Whipworms are mainly found in the large intestine close to the junction with the small junction with the small intestine in a pouch known as the cecum (caecum).
Whipworms attach to wall of the intestine by burying their head in the wall. They feed by sucking on blood.
Compared with roundworms, hookworms and tapeworms, the life cycle of whipworms is the simplest.
Adult female whipworms release eggs which pass out of the dog in the stool.
The newly released eggs are not infective. Under the right conditions of temperature and humidity it takes 2 to 4 weeks for the development of a larva within the egg that is infectious.
The eggs are very resistant to drying up and can remain infectious for many years in the soil.
The most common way for a dog to eat an egg is for the egg to get on the dogs paws and then swallow the egg when they are grooming.
After being swallowed the larvae hatch in small intestine and migrate into the wall there. They remain in the wall for about 2 weeks and then travel to the large intestine. After a period of further development they become mature whipworms. It takes about 3 months in the large intestine before the female whipworms start to release eggs – and the cycle repeats.
The symptoms of a whipworm infection generally depend on the level of the infection.
If there are low numbers of worms in a healthy dog there will usually be not symptoms.
Larger number of worms will cause irritation of the intestinal wall. This irritation can cause the intestine to produce large amounts of mucus. Often there will be diarrhea, which can happen occasionally, be frequent or be occurring all the time. The diarrhea will be gooey due to the mucus and is often bloody.
Weight loss and anemia can also occur with large number of worms.
Rarely whipworms can cause death.
Since female whipworms only shed eggs periodically it can be hard to diagnose whipworms by finding eggs in the stool. Even with repeated screening of stool at intervals eggs will not be detected. Therefore, if the symptoms indicate whipworms a vet will frequently start de-worming treatments.
Whipworm treatment requires a de-worming agent that kills whipworms – not all de-wormers kill whipworms. The most usual ingredients are fenbendazole and febantel. There are two commonly used products that are effective against whipworms are Panacur C and Drontal Plus. Both are used by vets. Drontal Plus is prescription only. Panacur C can be purchased without a prescription.
The dose for Panacur C is 1 gram per 10 lbs, so calculate the number of grams needed and then buy the size combinations to get the correct dose. As an example a 60 lb dog would require 6 grams, so one each of the 2 gram and 4 gram sizes would be needed.
Since whipworms are in the large intestine it is harder to get a high enough concentration of the de-wormer. This makes it hard to get rid of every single whipworm. Most vets recommend that after the initial treatment, de-worming it is repeated at 3 weeks and also at 2½ to 3 month to kill as many whipworms as possible.
High doses of ivermectin (much higher than is in Heartworm medication) will kill whipworms. However, some breeds (including most types of Collies, Australian Shepherds, Old English Sheepdogs and crosses to these breeds) cannot tolerate these higher doses of ivermectin and will get very sick and may die. Since there are other effective de-worming agents for whipworm that do not carry this risk, ivermectin is rarely used for de-worming.
Unlike roundworms and hookworms, many of the heartworm medications are not effective against whipworms. (See Table of Heartworm medications and worms against which they are effective). If your dog has previously been diagnosed with a whipworm infection it may be worth making sure your dog is on a Heartworm medication such as Interceptor, Sentinel or Advantage Multi to help eliminate any residual worms.
Occasional de-worming with Panacur C may be helpful in the case of a dog has a low infestation of whipworms and no symptoms.
Since whipworm eggs are so tough and can be infective for many years they are very hard to eradicate from the outside environment. The only way to decontaminate an outside area is to cover the area in concrete of black top or remove the topsoil.
Humans very rarely get infected with the dog whipworm Trichuris vulpis. The treatment for dog whipworms is the same as for Trichuris trichiura, the human whipworm.
A few people have been infected deliberately with eggs of the pig whipworm Trichuris suis, to test whether a low level infection of a parasitic worm stimulates the immune system and reduces the symptoms of inflammatory bowel diseases. The theory is that until recent history most humans would have been infected with parasitic worms and the immune response to these infections protected against diseases such as Crohn’s disease.
Whipworms are a common parasitic worm of dogs. Since the eggs are so tough it is very hard to get rid of egg infested soil and eradicate them from an area.
Dogs with a light infection of whipworms will often have no symptoms. Completely eradicating whipworms from the intestines of a dog is difficult. Multiple treatments of an appropriate de-worming product are required. Unlike for roundworms and hookworms, many heartworm medications are not effective against whipworms.
Image courtesy of Wikipedia – the narrow end is the head and the thicker end has the reproductive organs