One of the lesser-known parasites that pose a danger to dogs is the whipworm. Whipworms, like most parasites, are resilient. In egg form, their hard shells allow them to survive outdoors in the soil for years in the time. In many ways, whipworms are like hookworms, but instead of ending in a hook shape, one end of this worm tapers to a narrow, whip-like point.

Unlike hookworms, whipworms can't enter the body through the skin. The only way for your dog to contract them is by eating the eggs. Whipworms exist throughout North America, and transmission is easy if your dog has any contact with other dogs. The long-lived eggs can show up in the soil, dog toys, discarded bones and water dishes. Once eaten, whipworms then grow to maturity inside your dog's digestive system.

When they reach maturity, the adult worms fasten themselves to the large intestine and the cecum, a transitional pouch between the large and small intestine. Here, these nasty little parasites slash and puncture the intestinal walls in order to feed. The female starts to lay her eggs, which the dog excretes through the feces.

Symptoms for whipworm resemble those for other worms, such as hookworm. Many dogs can carry a certain number of whipworms without showing distress, but past a certain point, your dog may begin to exhibit signs such as a dull coat, anemia, rapid weight loss, and a loose and bloody stool. He may also begin vomiting up a yellow-green substance. In very severe cases, the worms may begin to puncture the intestinal wall, to the degree that the intestine begins to stick to the body wall. In this case, you might see your dog licking and worrying his right flank.

When you take your dog to the vet, it may take some time to diagnose him with whipworm. Whipworms lay eggs only intermittently, and even when they’re actively releasing eggs, any diarrhea in your dog can make the eggs hard to find. Typically, vets will perform four stool samples over four days before ruling out whipworm.

If your vet finds whipworm eggs, she'll administer a potent dewormer. But all whipworm dewormers on the market are only effective against worms in their adult form. As a result, you'll probably need to re-treat your dog.

There are no simple and effective ways of removing whipworm eggs from the soil around your house. However, a contaminated environment can infect your dog over and over again. The best way to combat reinfestation is to make sure your dog's quarters are sunny and dry, since whipworm eggs require moisture. Try to place him in an area of fresh new gravel, pavement or soil.