Giardia in Dogs: Symptoms, Causes, Treatment

Digestive problems are very common in dogs and if your dog has diarrhea, it can happen from many things including eating something they shouldn't to a sudden change in diet. Sometimes an intestinal parasite is behind the problem. Giardia in dogs is one such infection, and it can cause everything from mild, occasional digestive upset to more persistent diarrhea.

While some dogs with Giardia show no obvious signs at all, others can become uncomfortable and lose weight if the infection continues. It is important to knowing what Giardia is, how dogs catch it, and what to watch so you can recognize a potential problem and get dog the right care.

What Is Giardia?

Giardia is a tiny parasite (microscopic) that is in the intestinal tract of dogs and other animals. The infection caused by Giardia is called giardiasis. This parasite interferes with normal digestion and can affect the way a dog’s intestines absorb nutrients and water.

Giardia exists in two forms. The active form is located in a dog’s intestines, while the cyst form survives outside the body and allows the parasite to spread from one host to another. Giardia cysts can survive in cool, damp conditions, which makes contaminated water, soil, and surfaces potential sources of infection.

Dogs can become infected with Giardia at any age, although puppies and dogs that have a weakened immune system may have a harder time dealing with the infection.

How Dogs Can Get Giardia

Dogs usually get Giardia by swallowing Giardia cysts from a contaminated environment. A dog may drink from a puddle, stream, or other contaminated water source, lick contaminated soil, or come into contact with another dog’s infected feces.

Dogs can also pick up Giardia cysts from contaminated surfaces, including kennels, daycare areas, dog parks, bedding, food and water bowls, and other shared spaces. Because dogs naturally investigate the world with their mouths, it doesn't take much for them to accidentally ingest the parasite.

Giardia can also spread from dog to dog through fecal contamination. A dog doesn't necessarily have to directly eat feces to become infected. Simply stepping in the contaminated poop and later licking their paws can cause Giardia cysts to enter the digestive tract.

What Are the Symptoms of Giardia in Dogs?

Some dogs with Giardia don't develop any symptoms at all. These dogs can still shed Giardia cysts in their feces and potentially contaminate their surroundings.

When symptoms do occur, diarrhea is one of the more common symptoms of Giardia in dogs. The diarrhea may be soft, watery, or have an unusual odor. Some dogs may also have mucus in their stool.

Other possible signs include changes in appetite, gas, vomiting, weight loss, dehydration, or a generally uncomfortable stomach. Some dogs develop diarrhea that comes and goes rather than having constant digestive problems.

Because these symptoms can occur with many other gastrointestinal conditions, you can't determine that a dog has Giardia based on symptoms alone.

Does Giardia Cause A Dog To Lose Weight?

Weight loss can occur with Giardia, especially when the infection lasts for a while or causes digestive issues. The parasite can interfere with normal nutrient absorption, while ongoing diarrhea can cause a dog to lose fluids and nutrients.

A dog with Giardia may also have a reduced appetite, which can make weight loss more noticeable. Puppies and smaller dogs can be especially vulnerable to the effects of prolonged diarrhea and dehydration.

Any unexplained weight loss deserves attention from your veterinarian, especially when it occurs alongside persistent diarrhea or other digestive symptoms.

How Is Giardia Diagnosed in Dogs?

A veterinarian can test your dog's stool for Giardia. Because dogs may not shed Giardia cysts consistently, and one stool sample doesn't always provide a complete picture. Your veterinarian may recommend additional testing or testing more than one sample if Giardia remains a concern.

There are many types of fecal tests that can help identify Giardia, including tests that detect Giardia antigens or the parasite itself. Your veterinarian will determine which testing approach makes the most sense based on your dog's symptoms and medical history.

If your dog has recurring diarrhea, don't assume Giardia is the cause. Other parasites, infections, dietary issues, inflammatory conditions, and other gastrointestinal problems can produce similar symptoms.

How Is Giardia Treated?

Veterinarians usually treat Giardia with prescription medications designed to eliminate or control the parasite. The exact medication and treatment plan can vary depending on the individual dog and veterinary recommendations.

Treatment isn't always as simple as merely giving your dog medication and moving on. Because Giardia cysts can remain in the environment, dogs can potentially become reinfected after treatment.  Your vet might also recommend bathing your dog, cleaning contaminated areas, washing bedding, and keeping food and water bowls clean during treatment.

It's also important to give any prescribed medication exactly as directed and complete the recommended treatment, even if your dog starts feeling better before the medication is finished.

Can Giardia Come Back After Treatment?

Yes, dogs can become infected with Giardia again. A dog that tests positive after treatment may have a persistent infection, but reinfection from the environment can also occur.

Cleaning your dog's living environment plays an important role in reducing this risk. Make sure to pick up your dog’s feces immediately, wash your bedding regularly, clean your dog’s food and water bowls, and keep your dog away from areas that may be heavily contaminated with feces.

It can also be helpful to bathe your dog on a regular basis to help remove Giardia cysts from the fur, particularly around the hind end and paws. Your veterinarian can give you specific cleaning recommendations based on your dog's situation.

Can Dogs Get Giardia From Drinking Water?

Contaminated water is one of the ways dogs can pick up Giardia. This can include untreated water from streams, ponds, puddles, and other outdoor sources.

That doesn't mean dogs need to avoid every outdoor water source, but pet parents should use caution around stagnant or potentially contaminated water. Providing fresh, clean drinking water during walks, hikes, and trips can reduce the temptation for your dog to drink from questionable sources.

Can Humans Get Giardia From Dogs?

Giardia can infect people, but the risk of a person catching Giardia from an infected dog appears to be relatively low. Giardia strains can differ between animals and people, and not every type that infects dogs commonly infects humans.

Still, good hygiene matters. Anyone caring for a dog with Giardia should wash their hands thoroughly after handling feces, cleaning contaminated areas, or helping the dog with hygiene. Children should also be supervised around an infected dog and encouraged to wash their hands after interacting with pets.

Can You Prevent Giardia?

You can't completely eliminate your dog's exposure to Giardia, but you can reduce the chances of infection. Preventing your dog from drinking untreated water is a good place to start. It's also important to pick up your dog’s poop promptly, especially in your own yard and in shared areas.

Keeping your dog's bedding, bowls, toys, and living areas clean can also help reduce environmental contamination. In households with multiple dogs, extra attention to hygiene becomes particularly important when one dog has been diagnosed with Giardia.

If your dog seems to pick up Giardia at the dog park, it might be a good idea to stop going there. Or at least until your dog gets better.

Regular veterinary care and fecal parasite testing can also help identify intestinal parasites before they become a bigger problem.

When Should You Call the Vet?

Diarrhea that lasts more than a day or two keeps coming back or occurs with other symptoms deserves a conversation with your veterinarian. Puppies, senior dogs, and dogs with underlying health problems may need attention sooner because diarrhea can lead to dehydration more quickly.

Contact your veterinarian if your dog has severe or persistent diarrhea, repeated vomiting, significant lethargy, refuses food or water, appears dehydrated, or is losing weight. Bloody stool or a dog that appears seriously ill also warrants prompt veterinary attention.

Final Thoughts

Giardia is usually manageable with the appropriate veterinary care, but identifying the cause of ongoing digestive problems is equally important. With treatment, good hygiene, and a little extra attention to your dog's surroundings, most dogs can get back to feeling like themselves.