Six crucial things you should know about Giardia

Dr. Edison Barrientos Dundas-Euclid Animal HospitalSummary: Giardia can end up being an important issue if you do not understand what you are dealing with, that’s why Dr. Barrientos has taken the time to answer the six most important questions about this parasite.


Giardia is an extremely common digestive tract parasite. It’s important to know that it is not a virus, bacteria or a worm, it’s a unicellular protozoan parasite. It resides in the intestines of cats and dogs, it can also affect human beings and trigger intestinal upset, vomiting and diarrhea and in the case of dogs, poor growth. The name of the infection caused by this parasite is called Giardiasis.

Giardiasis may be a relevant factor for illnesses, particularly diarrhea, in both animals and humans. However, numerous pets contaminated with Giardia do not get diarrhea, throw up, or show any other signs of the disease.


Some pets can get rather sick. They may show different levels of dehydration, diarrhea and vomiting. Younger dogs in their growth phase may not reach their full growth potential and end up becoming unthrifty. Sometimes you have some pet dogs who have the ability to control Giardia on their own and they don’t look like they are sick. Even so, they may be transferring the Giardia infection to other dogs they encounter in public spaces, so it is essential to test for it by doing a fecal sample and if it comes out positive, start treating it.

Giardia is a unicellular protozoan parasiteWHAT DOES GIARDIA POOP LOOK LIKE IN DOGS?

Generally, dogs with Giardia have softish bowel movements. They range from moderately soft, like melted ice cream all the way to severe diarrhea. That’s one of the most common signs. Even so, you will sometimes have dogs that are infected that have normal stool, this is why testing for Giardia is so important.


As mentioned before, Giardia can be easily identified through a stool or fecal sample. Treatment involves medication, the first choice is usually Fenbendazole, if that does not do the job, then we use something called Metronidazole. The parasite can be quite resilient and may require numerous bouts of treatment to effectively remove it. In addition to medication, things like probiotics and a good digestible diet are likewise effective in controlling it. Some dogs may require follow-up testing and treatments based on their condition and the intensity of the infection. All contaminated animals must be re-tested 2 to 4 weeks after finishing the treatment.


Check your dogs annually for giardiaThankfully, the chances of humans being contaminated with Giardia from pets is reasonably low. There are seven different variants of this intestinal parasite, they are assigned letters A through G. Canines are most commonly affected by types C and D, felines with F, and humans mostly infected with A and B. Nevertheless, it is still possible! So to reduce the danger we advise thorough hand washing after handling your pet’s poop and also by keeping your dog’s toys, food and water bowl as clean as a whistle!


Good personal hygiene & environmental disinfection will help prevent unintentional spread to people and pets if your dog has giardiasis. People with immunodeficiency, AIDS or cancer, or who are going through chemotherapy, must be very careful, especially when dealing with feces or after administering medications to their pets.

To avoid getting this parasite, the first thing we recommend is to take your pet to the veterinarian to test and make sure they are not infected. Once that’s taken care of, good hygiene and simple precautions can actually help a lot. When you are out on long walks bring your own water along (and a dish) so your dog doesn’t have to share it with other pets. Always clean your hands as soon as possible after managing your pet’s stool. Always keep their water and food dishes clean, and this also includes toys & accessories. It is also important to do stool tests on your dog at least once a year.

Dr. Edison Barrientos

This article provides a summary view of some aspects you need to know about pets and how to care for your new kitty. We recommend you take the time to talk in detail with one of our licensed veterinarians. They will provide the best suggestions and strategies for your pet. For an appointment please contact us at 416-362-9696 or click the button below.

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  • Anna Burke, “The Facts You Need to Know About Giardia in Dogs”. American Kennel Club  [source]
  • Ernest Ward, DVM, “Giardia in Dogs”. VCA Hospitals [source]
  • Cascade Heights Veterinary Center. “Have Questions about Giardia?” [source]
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