All About WhipwormsWhipworm (Trichuris Vulpis) is essentially a parasite of the large intestine and cecum, a large pouch that forms the beginning of the large intestine. (The cecum is the equivalent of a human's appendix.) This parasite, called Trichuris vulpis, lives in the caecum of dogs ( a part of the large intestine). It mainly infects dogs over twelve weeks of age. The worm is called a whipworm because it looks like a stock whip. Using its mouth spear much like a sword, it slashes and punctures its way through the intestine, feeding on blood and tissue fluids as it goes. Although it consumes less than the Hookworm, severe infections (>2,000) can cause a significant anemia. The worms range in size from 1.75 to 3 inches. Canine whipworm is widely distributed throughout North America.
The whipworm eggs come out in the dropping of the dog and develop larvae still inside the egg shell. These larvae, unlike the hookworm larvae, don't hatch out on the ground. A dog will pick up the eggs by licking his paws or from the ground. The eggs will hatch out in the small intestine, pass down to the large intestine and start establishing themselves as adults. This takes at least twelve weeks. ingesting eggs containing infective larvae. When the eggs hatch in the intestine, the larvae burrow into the wall of the cecum and small intestine and remain there for 2 to 10 days. They then migrate to the large intestine where the adult worms develop.
The life span of the adult canine whipworm ranges form 5 to 16 months. Each female whipworm may produce 2000 eggs per day. In addition, eggs may survive in the soil for up to five years waiting to infect a passing dog. Once infected, the infective larvae mature to an egg laying adult in approximately 3 months. It is this long prepatent period and the resilience of the eggs in the environment that make whipworm so difficult to control. Unlike other worms, whipworm does not migrate through the dog's tissues as part of its life cycle. Ingested eggs hatch directly in the small intestine.
Generally a dog's response to a whipworm infection is relatively mild, although exceptions do occur. Heavy infections can result in bouts of diarrhea and feces may be streaked with fresh blood. Young dogs or dogs with a chronic infection can suffer severe weight loss, dehydration due to diarrhea, and anemia. Death can occur if the infection is severe enough. Many dogs will carry infections of whipworms without much problem. Some dogs, however, will develop periodic smelly diarrhea which can become a severe problem. Large numbers of whipworms irritate the lining of your dog's intestine causing weight loss and pain.
Whipworms are not dangerous to people, but once dogs become infected, whipworms are difficult to eliminate without medication programs. Large amounts of mucous are produced by the inflamed intestine. Sometimes hemorrhage into the intestine occurs and anemia can result. In very heavy infestions the worms may penetrate through the intestinal wall and the resulting inflammation causes the intestine to adhere to the body wall. Animals with this condition may frequently lick their right flank where the adhesion occurs.
Whipworm is usually diagnosed by identifying its smooth-shelled, bi-polar, plugged eggs using fecal flotation. Diagnosis can be difficult, however, because the female produces relatively few eggs, and she produces them intermittently. Also, in dogs suffering from bloody diarrhea as a result of the infection, finding the eggs can be difficult. Zinc sulfate is a much more reliable method of diagnosing whipworm infection than traditional floatation methods employed by most clinics.
A minimum of four fecal exams over a four-day period should be conducted before a negative diagnosis is made. Because of intermittent egg-shedding, a whipworm infection may not be correctly diagnosed. A follow-up exam may be necessary to rule out the possibility of infection.
Whipworm infections can be difficult to treat due to the high incidence of re-infection from contaminated environments. Eggs, because of their thick shell are very resistant, they can remain in the environment for as long as 5 years , and in areas where whipworm is prevalent, it is almost impossible to prevent re-infection unless measures are taken to treat the dog most frequented areas. Even then, the eggs are resistant to most cleaning methods and re-infection is likely. The long (3 month) prepatent period means that dewormers given at a 2 to 3 week intervals would not control the immature stages, and treatment for this worm must be long term if there is to be any chance of success.
Whipworms eggs are somewhat susceptible to drying, but can remain alive in moist soil for years and are resistant to freezing. Because of this, animals should be restricted from contaminated areas. There is no effecive method for killing whipworm eggs in the soil. The only alternative is to replace the soil with new soil, gravel and pavement. To prevent exposure, any feces in the yard should be picked up on a daily basis. Routine fecal examinations and wormings can help control this parasite.
Treatment and control for whipworm currently includes Milbemycin Oxime found in both SENTINEL and INTERCEPTOR. Both of these products offered by Novartis Animal Health are GUARANTEED to remove the adult worms with each monthly dose. Depending on the situation and environment your dog is in, your veterinarian will be able to prescribe the appropriate medication to treat your dog for these parasites.
It is important to note that all canine dewormers currently available are labeled as being effective only against the adult stage of the worm. Within weeks or even days of deworming, immature larvae that were present in the gut, but unaffected by the medication, will develop into mature adults and begin laying eggs again. Although it is possible to see eggs on a fecal examination, regular monthly doses of INTERCEPTOR or SENTINEL are guaranteed to wipe out the new adults at the time of each dosing. The worms will not be able to establish themselves in a significant way within the pet, and the dog will not show clinical symptoms of whipworm disease.
As in human medicine, veterinary medicine is shifting its focus from the treatment of diseases and symptoms, to the prevention of them before they have a chance to harm your pet. In the same way that vaccines prevent your pet from developing formerly common diseases, it is now an accepted practice to include deworming medication at regular intervals, to keep your pet healthy and free of parasites.
Important points to remember about whipworm.
- Whipworm infects dogs over 12 weeks of age and can be a problem in adult dogs.
- Dogs become infected by contamination from their own or other dog's droppings.
- Whipworm eggs will remain infective for very long periods.
- The bitch does not infect pups with whipworm except from her droppings.
- Control measures for whipworm include:
- Careful attention to hygiene (removal of droppings).
- Avoidance of dirt runs.
- Regular treatment programme.
- Dogs confined in small, outside areas are at highest risk at having whipworms.