top of page
  • Jennifer Misfeldt, MABTR

Parasites causing loose stools in dogs

Updated: Sep 5, 2023



Dogs can get parasites (such as roundworms, whipworms, hookworms, and tapeworm) and bacteria that can cause loose stools and in many cases are contagious to other dogs. The infection can result in significant gastrointestinal (GI) upset.


Giardia and Coccidia are the most common intestinal parasites found in dogs. that cause loose stools, bloody or mucus-coated stools, watery diarrhea, weight loss, dehydration, and lethargy.

Dogs can easily transmit giardia and coccidia when interacting with their canine companions at a dog park or drinking from a natural water source. Parasites are contagious with dogs eating infected feces, soil contaminated from feces.


Parasites such as worms are very common in puppies and the result of the pot-bellied appearance. All puppies need to be dewormed multiple times as puppies. Dewormer is based on weight and to be purchased at a vet.

Dogs of all ages can get worms but tapeworms are contagious to other dogs. Not many adults show symptoms when infected. Things to look for is softened stool, blood in the stool, loss of appetite, loss of weight.


*Tapeworms look like white rice) are not contagious from dog to dog as they are from fleas. If you dog has tapeworm they more likely have or had fleas and recommend they also be treated form flea dermatitis with a topical such as Frontline. The dewormer to get rid of tapeworms is Drontol Plus.


A dog can contract in numerous ways, including by:

  • Ingesting infected fecal material

  • Ingesting fecal-contaminated soil or plants

  • Drinking contaminated water

  • Sniffing an infected dog’s hind end

  • Rolling on contaminated soil and grooming their fur afterward

  • Eating infected small animals

Diagnosing and treating:

You need to have a fecal done at your vet clinic. In some cases it is recommended it be sent out for specifically testing for parasites and bacteria.

Treatment is a prescribed medication, nothing over the counter. In some cases it may take two or three rounds to clear the infection with a repeat fecal test after each round of medication.

Your vet may recommend supportive care, such as intravenous (IV) fluids, if an affected dog is dehydrated or has electrolyte imbalances.


While humans can contract these parasites, you are typically infected if you drink contaminated water. Wash your hands thoroughly after handling your dog or their feces.

bottom of page