The canine whipworm is an especially intractable parasite if your dog becomes infested and then contaminates your yard with whipworm eggs expelled in the feces. Most dogs do not carry whipworms, and you can easily rid your dog of the egg-laying adult whipworms or prevent infestation in the first place through regular vet checks and the use of the correct wormer. However, it is easy for the dog to be reinfested repeatedly once whipworm eggs are present in the soil where the dog lives. Whipworm eggs deposited in an infested dog's droppings can survive in the soil five years or more, and are particularly difficult to eradicate. The whipworm species that affects dogs and foxes generally doesn't survive in people or other species, but rarely they do, and it's important to avoid the possibility, especially in children. Ridding soil of whipworm eggs is difficult. In some situations, the dessicating effect of soil additives such as lime may be useful, but treatment of large yards in this way generally is costly, impractical and ineffective.
How Infestations Start
Whipworm eggs are deposited in the soil when an infected dog, coyote or fox defecates. If a new host, such as your pet dog, comes in contact with whipworm eggs, he may later swallow them while grooming himself. The swallowed eggs hatch in your dog's intestine. Within three months, the hatched whipworms have taken up residence in the dog's large intestine and are egg-laying adults themselves. Your dog continues the infestation cycle by depositing fresh eggs on the ground in his droppings.
Whipworms can cause serious problems for your dog, but dog whipworms rarely will cause problems for you or your children. Whipworms are adapted to a specific host. Many humans in countries where sanitation is poor are infested by a whipworm species specifically adapted to humans. People with significant whipworm infestations can develop painful, bloody diarrhea. Children who live with untreated whipworm infections can become anemic and suffer from stunted growth. Heavy whipworm infestations in dogs can cause bloody diarrhea, weight loss, dehydration and anemia. Puppies are especially vulnerable to the symptoms of whipworm infection. Whipworms do occasionally infect cats, though such infestations are rare.
Powdered agricultural lime made from limestone or chalk is a common treatment for whipworm soil infestations. You can buy lime in 40- to 50-lb. bags. Sprinkle enough lime over the infested soil's surface to cover it thoroughly in a layer about 1/2 inch deep. For extra measure, work some of the lime into the topsoil with a garden cultivator or rake, and reapply one more coating of lime. The lime works by drying out whipworm eggs. However, the treatment doesn't work unless your soil stays dry for at least two weeks. Rain or sprinkler water that wets the lime application will prevent it from killing whipworm eggs.
Because lime won't work if your soil is wet, you may need to try other techniques. You can replace infested soil with new soil, or place a thick layer of gravel over the site to prevent whipworm eggs from coming into contact with pets and people. If your dog lives outside, you may need to pave over infected soil to avoid repeated whipworm infestations.
Stopping the infestation cycle requires treating your infected pet and practicing good backyard hygiene. Your vet will prescribe a deworming medication such as Panacur or Drontal Plus. Because whipworms have a three-month maturation period, you'll need to repeat the treatment at least once. A monthly dose of the worm killer milbemycin oxime can keep fresh infestations from taking root in your pet. Some heartworm medications will also prevent whipworms. Check with your veterinarian on which of these are available. To prevent soil contamination, pick up dog feces immediately. Whipworm eggs must sit for two to four weeks to form embryos before they become infectious. With diligent treatment for your pet and constant cleanup in your yard, your soil should eventually be whipworm-free.