Worms in Dogs

Medically Reviewed by Amy Flowers, DVM on November 09, 2022
3 min read

Canine worms can cause a variety of health problems in dogs. Here you’ll find a brief description of the most common types of worms in dogs, with links to in-depth articles on how these worms can infect your dog and what you can do to prevent and treat them.

Roundworms

Usually spread in feces or during pregnancy or nursing, the roundworm causes a serious infection in dogs and puppies. The roundworm eats the food of its host and may cause diarrhea and other symptoms. In puppies, roundworms can be fatal. Prescription and over-the-counter deworming products for dogs are very effective. If people contract roundworms, their symptoms can be even more serious than those in dogs. Read the full article.

Hookworms

Living mainly in the small intestine, hookworms suck the blood of their hosts. Puppies can become infected from their mothers. Adult dogs or puppies can be infected through their skin or when cleaning themselves. They can also be infected by eating another animal that is infected. The infection causes weakness and malnutrition and can lead to death in puppies. Two rounds of deworming medication are usually effective, but a puppy may need other treatment, as well. Humans can also become infected with hookworms from unwashed vegetables or by walking barefoot on sand and soil. Read the full article.

Heartworms

Heartworms are spread to dogs through mosquito bites. Up to 14 inches long, a heartworm lives in the heart and the arteries that carry blood from the heart to the lungs. Heartworms affect how the heart functions and how blood clots and is likely to cause death if untreated. Heartworm preventives are effective. If infected, your dog may cough, have trouble breathing, and experience other symptoms. Treatment may involve two or three injections of arsenic-based drugs, followed by at least three months of rest.  Read the full article.

Whipworms

Whipworms live in the area where the small and large intestines meet. Here, they suck the blood of their hosts. Dogs can pick them up from contaminated soil or by grooming. Whipworms can be quite serious and cause bloody diarrhea when there are large numbers embed in the intestine. Some heartworm preventives are effective against whipworms, and an oral dewormer is effective at eliminating whipworms. Read the full article.

Tapeworms

Dogs get tapeworms from swallowing fleas, which carry them. Tapeworms absorb some of the dog’s nutrients from the intestine where they attach. The tapeworm is made up of small segments, each about the size of a grain of rice. These are passed in feces and can sometimes be seen around the dog’s anus. An injection or tablet can kill tapeworms. Humans can also get tapeworms, but people don't get them from an infected pet. Read the full article.

Ringworm

Despite its name, ringworm is not a worm at all. It is a skin infection caused by a fungus. In dogs, ringworm often presents as a dry, gray, scaly patch, although it may cause no symptoms at all. In people, it forms a round, red lesion with a ring-like appearance. Dogs pick up ringworm when their skin comes into contact with the spores of the fungus. Spores are commonly found in the soil or on cats. The spores can be present on a cat even when it shows no symptoms. People can catch it by touching an infected pet. Treatment for ringworm in dogs may involve medicated dips, shampoos, or ointments. Your dog may also need oral medication for one to two months. You may need to take other measures to clear ringworm from the environment or prevent its spread. Read the full article.