Giardia in Dogs: Causes, Symptoms, Treatment, and More

Giardia in Dogs: Causes, Symptoms, Treatment, and More

Last Updated on February, 2023

If your dog has been having an upset tummy, it may be a sign of Giardia.

And it can make your pooch miserable. So, it is wise to be alert to the crucial facts about Giardia.

Luckily, in this article, you will learn ALL the things to know about Giardia in dogs.

Keep reading to discover the causes, symptoms, diagnosis, treatments, and prevention of Giardia.

Let’s get started!

What is Giardia?

giardia virus in a dog

Giardia is a single-celled parasite that exists in animals’ intestines. This organism causes many digestive issues and can be a severe gastrointestinal disease.

Giardia organism is NOT a worm, virus, or bacteria. And it is the most common intestinal parasite found in dogs.

It is a dangerous parasite that has many subspecies. These categories target different species of animals.

Giardia intestinalis (also called Giardia duodenalis and Giardia lamblia) is the species that infects mammals.

And these gastrointestinal parasites have a two-stage life cycle. It includes the mature form and the trophozoite. Moreover, the trophozoite multiplies and transforms into Giardia cysts.

They are infectious cysts and can SURVIVE for several months in the environment. Infected animals’ feces will contain cysts.

As a result, the cysts can come into contact with the animals in the surroundings.

Giardiasis is the intestinal infection humans, and animals get from the parasite Giardia.

Besides, did you know that 15% of dogs already have Giardiasis?

Of course, this organism is COMMON in almost every country, including the U.S.

Related articles:

How do Dogs Get Giardia?

Dogs are more likely to get Giardia if they ingest the cyst stage of the parasite.

They love to put stuff into their mouths, right?

So, that means there are TONS OF WAYS to ingest the dangerous parasite in their surroundings.

Your pooch can get Giardia by drinking water, eating food, or sniffing something that carries Giardia cysts. 

a dog biting a stick

Also, your dog can get Giardia infection if they eat poop from the ground or a dirty litter box.

Moreover, contaminated soil and plants are also possible causes of the disease. These cysts can survive for several weeks in soil.

Furthermore, a large number of cysts are widely present in places like kennels, dog parks, animal shelters, and pet stores.

Once your pooch ingests the cyst, it transforms into a trophozoite, absorbing nutrients from the infected animals. Then, the cyst attaches to the intestine wall while causing damage.

After Giardia is in your dog’s intestines, the parasite can transmit to other animals. However, the spreading from cats to dogs and dogs to cats is rare.


Giardia is extremely contagious from dogs to dogs. So, if your pooch has Giardia, there’s a HIGHER likelihood of transmission to other dogs.

So, if you have many pets at home, you should be more careful on this matter.

One infected dog may put other pets at risk too!

Related article: How to Stop Dog From Eating Poop Naturally?

What Does Giardia in Dogs Do?

a dog lying on the floor

Giardia in dogs is not always worrisome. But sometimes, it can be a HORRIBLE experience.

If your dog has the parasite in the intestines, the dog will be unable to absorb nutrients, water, and electrolytes.

As a result, your pooch will experience diarrhea and melt off. In some cases, diarrhea may be intermittent or continuous. 

Moreover, failure to diagnose and treat Giardiasis may cause severe weight loss and even death in serious conditions.

In particular, Giardiasis is DANGEROUS for puppies, senior dogs, and dogs with compromised immune systems.

What are the Symptoms of Giardia in Dogs?

a human touching a dog's tummy

Some dogs infected with Giardia may not show any symptoms. On the other hand, some dogs may display intermittent signs and appear as healthy dogs most of the time.

So, there is a possibility of healthy dogs carrying Giardia.

However, young dogs are more likely to display clinical signs.

In most cases, Giardiasis triggers tummy issues.

Sometimes, the infection can be life-threatening if your pooch’s immune system is immature or immunocompromised.

So, dog owners should BE AWARE of the symptoms and other signs of Giardiasis.

Diarrhea is the most common symptom of Giardiasis. The infection affects the intestinal walls. As a result, your pup may experience watery diarrhea or fatty stool.

Severe diarrhea may lead to dehydration. In some cases, watery diarrhea can be fatal for weak adult dogs and puppies if left untreated.

The disease may also cause vomiting in many pups. Thus, weight loss will occur. In addition, weight loss will result in poor coat appearance.

Moreover, infected dogs will suffer from decreased appetite and decreased energy.

How to Diagnose Giardia?

If you notice your pup has diarrhea, seek medical advice from your vet as soon as possible. 

You should NEVER IGNORE diarrhea in your pooch.

The veterinarian will diagnose Giardiasis by analyzing a sample of your dog’s poop.

The vet will analyze the fecal sample to check for the presence of Giardia-specific antigens.

a dog pooping on the ground

The vet will examine your dog’s medical history when diagnosing the infection. Also, the veterinarian will conduct a physical exam to check for pain, gas, and possible Giardia susceptibility.

Some of the tests used are available to conduct in-clinic, while some tests require further lab testing.

Moreover, to analyze the signs of Giardiasis, the vet may conduct:

  • A fecal test for routine intestinal organisms.
  • A microscope evaluation.
  • A parvovirus test to disregard this deadly virus as a possible reason.

What are the Treatments for Giardia in Dogs?

a veterinarian giving treatment to the dog

Now let’s check out the treatments for Giardia in dogs.

Once the vet diagnoses the infection, they will give your pooch a treatment plan according to the severity of the condition.

Two common medications, Fenbendazole (a dewormer) and Metronidazole (an antibiotic), treat Giardiasis by killing the parasite.

Depending on the infection, your dog will have to take one or both of these medications for three to ten days.

Moreover, your pup will need rehydration fluids and nutritional supplements to regain lost weight and strength.

For instance, subcutaneous fluid therapy (fluids injected under the skin), administration of electrolytes, and injectable vitamins will benefit dehydrated dogs and puppies.

This nutritional support will promote gastrointestinal healing.

Giardiasis can be hard to remove from your pet and home at once. So, sometimes it will take multiple rounds of treatment to cure the disease.

Infected pets will also need re-tests for two to four weeks after the treatment completion.

NEVER allow your dog to share its food bowls or water with other pets.

Moreover, you should bath the infected pet regularly to remove the cysts from their fur. And it is also important to pick up and dispose of the feces as soon as possible.

You will also have to DISINFECT your pooch’s environment, including carpets, furniture, bedding, and household surfaces.

However, your vet will heal your dog’s Giardiasis and get them back to normal.

How to Prevent Giardia in Dogs?

You cannot always control your pooch’s environment, right?

But thankfully, you can take some actions to prevent Giardia in dogs.

Ready to learn? Let’s go!

The most important preventive action you should take is to give your dog access to fresh and clean water all the time.

a dog drinking water

Always get your dog to drink water from a clean bowl. Do not allow your pet to drink any other water.

This will ensure that the infected animal will not drink contaminated water from infected puddles.

Also, if your dog has access to tap water, install a water filter that can remove cysts.

Moreover, you will also have to boil your pooch’s water. Boiled water will not contain any cysts.

But LET IT COOL before giving it to your pup!

Another important thing is to pay attention to your dog’s general hygiene. For example, give them frequent medicated baths to ensure good personal hygiene.

And environmental disinfection is another crucial preventive action. You can use 1-2 cups of chlorine bleach mixed with 60-120 ml of water to disinfect the surroundings.

Make sure to clean the pet’s stool immediately to ensure the environment is safe from the infection.

Furthermore, keep the environment as dry as possible because Giardia cysts cannot survive in dry environments.

You can remove the possibility of exposure by not taking your dog to places with large amounts of dog feces.

Well, you can easily prevent Giardiasis in dogs. Don’t you think?

Can Dogs Give Giardia Infection to Humans?

a man and a dog lying on the floor

It is RARE, but Giardia can infect humans.

To be specific, people with immunodeficiency, for example, AIDS or cancer, are at a higher risk of getting Giardia from dogs.

These people should take extreme caution when handling their pet’s poop or after administering medications to the pets.

Genotype A of Giardia can infect dogs, cats, and humans. And Genotype B can infect humans and dogs.

Polluted water is a primary source of human-to-human transmission. And drinking contaminated water is the main reason behind Giardia in humans.

How do You Prevent Human Giardia Infection?

You have to take necessary precautions to prevent human Giardia infections.

So, check out the below tips to learn more about it!

  • Wash your hands with disinfectants after handling your pet’s stool.
  • Wear gloves after cleaning your dog’s poop, gardening, and working with dirt.
  • Avoid drinking contaminated water.
  • Disinfect the surroundings regularly.



Giardiasis can be an exhausting experience for many dogs and pet parents.

Of course, Giardia can create CHAOS in your pup’s digestive system.

Well, now that you know all the important facts about the disease, you can prevent it from happening. 

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Thomas Villalpando is the main author of IPet Guides. He spends his time reading, training, and working with several Dogs' behaviors. You can find more about him here.

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