Parasites such as worms, fleas and ticks can make your dog uncomfortable and even seriously ill. This page describes the most common parasites that can affect dogs. You should consult your veterinarian for the best way to prevent infestation in your dog and your home. The AKC Pet Healthcare Plan can help with the cost of providing quality healthcare, including preventive medicine, throughout your dog's life.

Internal Parasites

Hookworms are common in puppies, though dogs of any age can be infested. Hookworms are acquired by puppies from their mother by nursing and by adult dogs by swallowing the parasite's eggs or having the hookworm burrow into the skin. Infection can be prevented by keeping your dog's environment clean. Your veterinarian can detect hookworms by examining a stool sample under a microscope.

Roundworms are also common in puppies and can infect other dogs and children. They look like white, firm, rounded strips of spaghetti, one to three inches long. Your veterinarian will look for signs of roundworms in the stool sample. Again, keep your dog's environment clean to prevent infestation.

Tapeworms will cause your dog to lose weight and have occasional diarrhea. You'll know if your dog's got them because you'll see segments of the worms around his anus or on his stool. The segments look like grains of rice.

Whipworms are acquired by licking or sniffing contaminated ground. They live in the dog's intestine and are only detectable in a stool sample.

Heartworms enter a dog's bloodstream from the bite of an infected mosquito. The worms mature in the dog's heart, growing to twelve inches in length and effectively clogging the heart -- a very serious condition. Heartworm infection occurs throughout the United States but is particularly common in warm, mosquito-infested areas. Treatment is expensive and can be dangerous. Fortunately, you can keep your dog free from infestation by administering heartworm preventive pills.

External Parasites

Fleas are a very common problem. You will need to be diligent about flea control; if you're not, your dog can suffer hair loss, allergic reaction, and worms. You also risk infesting your house and family members as well.

If your dog has fleas, you should ask your veterinarian for the most effective way to rid them from the dog and its bedding and environment. Effective flea prevention is also available; ask your vet for the best method for your dog.

Ticks can cause a number of serious illnesses, including Rocky Mountain spotted fever and Lyme disease. Check your dog for ticks daily if he spends any time outside, and whenever you see one, take it off immediately. The best way to do this is to numb the tick with rubbing alcohol or petroleum jelly, then pull it off with tweezers. Once removed, kill the tick by putting it in a container of alcohol. Prevent an infestation by treating your dog with a medication, dip, spray or powder as recommended by your veterinarian.

Mosquitoes are more of a nuisance than a serious threat to dogs. The West Nile virus, an infection carried by mosquitoes, remains fairly low. Regardless of the risk, mosquitoes are a pain. They exist everywhere in the United States, except at elevations above 8,000 feet.

Lice and mites are microscopic organisms that feed on your dog's skin and cause itching, hair loss, and infection. Lice live in a dog's hair and can be killed by dipping with an insecticide effective against ticks or fleas. Various kinds of mites inhabit different areas of the dog, and the problems they cause are generally known as mange. Ear mites live in the dog's ears. Your dog may have mites if he shakes his head and scratches his ears. Scabies, which affects humans as well as dogs, is caused when mites burrow into the dog's skin and cause intense itching and hair loss. Scabies usually affects the ears, elbows, legs, and face. Demodectic mange causes hair loss around the forehead, eyes, muzzle, and forepaws. It's caused by a mite that lives in hair follicles and causes hair loss, thick, red skin, and infected areas. There is also a mite that causes "walking dandruff" on a dog's head, back, and neck. This mite also causes itchy red spots on humans. All mites should be diagnosed from a skin scraping by a veterinarian.