Giardia in Dogs: The Trouble with Puddles

Young dogs and puppies have a higher risk of infection of giardia than adults.
By Shea Cox DVM, CVPP, CHPV, March 2012, Updated June 2021
giardia in dogs

Diarrhea. Boy, do I see lots of this, and when I say “lots,” I mean lots. In fact, on some shifts, it feels like that’s all I see. One of the common causes of diarrhea in dogs worldwide is giardia, a ubiquitous single-celled protozoan parasite. Giardiasis is transmitted by a fecal-oral route, meaning that the parasite is swallowed in food and water (think: puddles, lakes and streams) contaminated with feces. Note: Your pet does not have to eat feces to get the parasite!

Infection can be present without symptoms, but when signs are present, the most common one we see is large volumes of watery poop, oftentimes with blood and mucus. Weight loss, decreased appetite and vomiting can occur as well.

How is the giardia in dogs diagnosis made?

Diagnosis is often made by evaluating fecal material under a microscope. However, this little parasite can be difficult to find. So, in addition, we use a nifty “snap test,” adding some stool to a solution that gives us a positive or negative result for giardia (like a pregnancy test for poop). This test is very sensitive to the presence of giardia in dogs.

Symptoms of Giardia

Symptoms of giardia in both people and dogs can include diarrhea, gas, abdominal discomfort, nausea, and vomiting. But remember, it is possible have an infections and show no symptoms of giardia. Signs of illness in dogs may include:

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  • Severe Diarrhea (often with blood and mucus)
  • Vomiting
  • Gas
  • Weight loss
  • Dehydration
  • Dry or poor coat appearance
  • Decreased appetite

How does one treat the Giardiasis parasite?

Generally, easily and inexpensively, provided your dog doesn’t get so ill that he or she needs IV fluids or hospitalization. The little puppy pictured is named Rascal, and he was hospitalized due to an infection with giardia. His diarrhea came on fast and furious, and because teeny puppies don’t have much “wiggle room” when it comes to bodily reserve, it caused a critical drop in his blood sugar. He required more intensive hospitalization, and made a full recovery.

Giardiasis is generally treated with an inexpensive antibiotic called Metronidazole (Flagyl) that is readily available. In small puppies, such as Rascal (see below), or dogs sensitive to this antibiotic, a dewormer known as Panacur can be used instead for five to ten days.

giardia in dogs - puppies at risk

How do I prevent giardia?

This best way to help prevent infection is to keep your dog from drinking from puddles, lakes, streams or other sources of stagnant water. I know, this can be difficult.

Dog park puddles carry a higher risk than, say, fresh rainwater pooled in a birdbath or fountain. Remember, giardia is transmitted by a fecal-oral route, and what better place to have concentrated levels of feces than a dog park, especially when some pet parents are not diligent about removing their doggy’s waste. Think of it this way: If a dog infected with giardia defecates on the grass, and the rain creates a puddle of water in grass, your dog is essentially drinking a giardia martini.

It may also be advisable to treat other animals in the same household while treating the infected, symptomatic pet. There is a vaccine available for giardia in dogs, but most veterinarians don’t recommend it unless your dog is at really high risk or is one of those pets who gets giardiasis frequently.

Can I get Giardia from my Dog?

Don’t forget: People can get giardia too. Younger children are at a higher risk as hands often find their way to mouths during outside playtime (grass can be contaminated with giardia cysts as well). And those adorable doggy kisses we love so much? Let’s just say that it is easier to accidentally ingest one of those little cysts than you might think.

There are also environmental control measures that can be taken to prevent reinfection. People should be vigilant in clearing fecal material from the environment. If your pet has been diagnosed with giardia, it is often recommended that you wash as many areas of your environment as possible, followed by disinfection with a solution of bleach diluted in water (another measure that is easier said than done).

As with anything medical, there is no one clinical sign that equals a definitive disease, and diarrhea happens to be of the most common clinical signs of any disease process. Because of this, if your pet has diarrhea that persists beyond 24 hours, or is very sudden and severe, a veterinary exam is in order.

And, on that note, I’ll leave you with this closing mantra: No drinka da puddle, no snout in da bay. Pick up poop in da yard, quickly throw it away!

Photo of Rascal: Shea Cox; Feature photo: Sushant Sodanwar / Unsplash

Dr. Shea Cox is the founder of BluePearl Pet Hospice and is a global leader in animal hospice and palliative care. With a focus on technology, innovation and education, her efforts are changing the end-of-life landscape in veterinary medicine.

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