Intestinal Worms in Dogs

Intestinal worms are a reasonably common cause of ill health in dogs.

It's not always easy to see the signs of worm infestation until your canine
companion has quite a few of these little wrigglers in his intestines.

There are four types of intestinal worms that can cause problems in your dog.


These worms cause diarrhea, ill thrift and a characteristic pot bellied appearance, particularly in puppies. In large enough numbers, they can actually cause an intestinal obstruction.

Dogs acquire roundworm either while they are in the uterus, while nursing from their mom, or by swallowing the eggs that are in the ground. Larvae make their way to the lungs where they are coughed up and swallowed, and they then develop into adult worms in the intestine.

If a human picks up a roundworm infection, the effects can be catastrophic. The larvae migrate through the eye, and when they die, the inflammation can cause blindness.


This is another intestinal worm that can make your dog seriously ill. He becomes infected by swallowing eggs from the soil, or the larvae on the ground may actually burrow their way through the skin of his feet. When they eventually make their way to his small intestine, they grow into adults, latch onto the intestinal wall and start drinking blood.

Hookworm can cause blood loss anemia, and this can be fatal particularly to young pups. These worms can also infect people, and the migration of the larvae under the skin causes an itchy red rash.


Your dog can pick up whipworm infection by eating soil contaminated by eggs. Whipworm eggs can persist in the ground for years and it's just about impossible to get rid of them. These worms live in your dog's large intestine and cecum, which is much like our appendix. They cause inflammation leading to diarrhea, often with blood and mucus. They're hard to diagnose from a fecal sample because the females only lay eggs intermittently.This means your dog could have whipworms but no eggs will be found in his stool.


These are the worms that give your dog an itchy bottom, and look like small wriggling grains of rice around his anus and on his feces. Their lifecycle involves the flea, and if your dog has fleas he is likely to have tapeworm too. He'll become infected when he swallows a flea while grooming himself.

Fortunately, tapeworms are not as dangerous as the other species of worms but in large numbers they may cause weight loss and general ill thrift.

What can you do to protect your dog (and yourself) from the dangers of worms? You can make an appointment with your vet to check your dog for worms. This involves a fecal test, so it's not invasive or expensive.

They may recommend that your dog be treated to get rid of any worms he may have in his intestine. There are several effective products that will do this; just make sure you use them according to directions. To keep yourself safe, always wash your hands after handling your dog or after cleaning up your yard.

Intestinal worms don't have to make your dog sick. With a little effort on your part, you can protect him from their effects and keep him in the best of health.