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Intestinal Parasites in Dogs

Reviewed by Jane Robertson DVM, DACVIM on Tuesday, April 15, 2014
Posted April 15, 2014 in Dog Diseases & Conditions A-Z

Parasites are a common and important cause of disease in dogs. Although most people know about external parasites like fleas and ticks, many do not realize that intestinal parasites can also cause significant health problems. 

What are intestinal parasites?
Intestinal parasites are parasites that live inside the host animal’s gastrointestinal tract. Examples include worms, like roundworms, whipworms, hookworms, tapeworms and protozoa, such as, giardia and coccidia.

How do dogs get intestinal parasites?
Dogs can contract intestinal parasites via different routes. Parasites are usually transmitted when an animal inadvertently ingests parasite eggs or spores in contaminated soil, water, feces or food. In the case of tapeworms, they can also be transmitted when a dog eats an infected flea. Puppies, on the other hand, usually get intestinal parasites from their mother. Transmission can occur in utero or from nursing.

Why should you care?
Intestinal parasites can cause malnutrition, weight loss, vomiting, diarrhea, and anemia. Besides making our pets sick, many of these parasites can affect people. According to kidshealth.org, “20% of dogs pass toxocara eggs in their stool.” Toxocara can cause damage to the eyes and untreated can lead to vision loss, especially in children.

Dog OutsideWhat are the symptoms of intestinal parasites?
While external parasites, like fleas and ticks, are easy to spot, intestinal parasites are rarely seen because they live inside your pet’s intestinal tract and pass microscopic eggs or spores in your pet’s stool that are too small to be seen by the naked eye. Tapeworms are one exception--they shed segments that resemble sesame seeds or grains of rice and are typically seen in your pet’s stool or around their rectum. Roundworms are another exception since they may occasionally be seen in your pet’s vomit or stool. Nevertheless, intestinal parasites are difficult to spot and you should not rely on seeing them before taking your dog to the veterinarian.

Besides being hard to detect, many dogs infected with intestinal parasites are asymptomatic. Even symptomatic dogs may go undetected because their symptoms can be nonspecific. The most common signs and symptoms of intestinal parasites are:

  • Scooting
  • Vomiting
  • Diarrhea
  • A distended abdomen
  • Weight loss
  • Occasionally coughing

Since dogs infected with intestinal parasites can exhibit no symptoms or subtle symptoms that can be easily overlooked; the best way to ensure that your dog is parasite-free is to take him to the veterinarian at least once a year for check-ups. Your

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Ruth has more than 15 years of experience in the veterinary industry as a companion animal veterinarian in private practice. Along with being a writer and media personality, she is also a founding member of IDEXX’s Pet Health Network team.