Giardia in dogs: What is it? And why does it matter?

Your dog can be infected with parasites, which can cause illness in pets and even humans. We sat down with Trupanion veterinarian Dr. Sarah Nold to learn more about Giardia in dogs and what to expect for your best friend.

What is Giardia in dogs?

Parasites can affect all different parts of your dog’s body. Giardia often will attach and reproduce in the small intestines of the GI tract.

Trophozoites are passed in the feces typically within a couple of weeks of becoming infected. These quickly turn into cysts, which are more capable of withstanding the harsh conditions outside of the dog’s body.

For example, cysts can survive for months in fecal contaminated in food, soil, or water. Cysts are killed by freezing temperatures and direct sunlight.

How do dogs get Giardia?

You may find yourself asking, “How do dogs get giardia?” It may happen easier than you think, like at the dog park or on your pet’s walk.

Consider the following:

• Your dog can become infected by eating infected dog’s feces
• Drinking fecal contaminated water
• Eating fecal contaminated food

The risk of acquiring Giardia is higher in places that are overcrowded or unsanitary. For this reason, infection with Giardia is more common where dogs are housed in groups, like at a shelter or kennel. It can also be frequently found in dog parks.

Young dogs are more likely to become infected with Giardia, as well as to show symptoms.

Once your dog ingests the giardia cysts, the trophozoites hatch and travel to the small intestine. From there they grow, multiply, and are passed in the feces. This is how the parasite spreads from animal to animal.

Giardia signs and symptoms in dogs

It may be hard to know if your pet becomes sick, as some don’t show symptoms. There are various signs of Giardia that you should be aware of and watch out for in your dog. These include:

• Diarrhea
• Decreased appetite
• Lethargy
• Weight loss

You might think that you can check for cysts in the feces of your dog, but they are invisible to the human eye. If you want to know whether your dog has giardia, you’ll need to have your dog’s fecal sample checked out by your veterinarian.

Not all dogs show signs of infection. Some infected dogs will spontaneously experience signs of giardiasis months after becoming infected. Puppies and dogs with weakened immune systems can experience more severe symptoms from infection. If your dog is acting abnormal, please seek medical treatment immediately.

Is giardiasis in dogs dangerous?

Every dog is different and may respond differently when they’re sick.

More severe symptoms are a concern in dogs with other GI parasites or other illness, like IBD.

Any sudden weight loss should be a cause for concern. Particularly, if your dog has a suppressed immune system. In most cases, your dog may simply have diarrhea. This can lead to dehydration. It’s recommended to contact your veterinarian and get the appropriate treatment plan for your best friend.

How to treat Giardia in dogs

First, you’ll need to put your dog’s medical insurance to use and visit your veterinarian. They can run tests to check whether your dog is infected with giardia and discuss treatment options with you.

In some cases, especially if your dog doesn’t have any symptoms, only monitoring may be recommended.

Typically, the best form of treatment will be medicine taken from the comfort of your own home.

Preferably your dog will receive a bath during the course of treatment and again at the end of treatment. At a minimum they should receive a bath at the end of treatment. You will need to give your dog a good and thorough bath to get rid of any cysts that could be on your dog's coat. Pay particular attention to any areas on your dog that are more likely to have been contaminated with fecal matter, like the hind legs.

Any toys, furniture, and carpet they may have contact with should also be cleaned to make sure that there are no cysts around the home. Also, clean up feces in the yard. While surfaces can be cleaned with bleach, the carpet should be steam cleaned, and any toys must be soaked in boiling water. Remember, this parasite is very tough to kill and can affect humans.

Giardia medication for dogs

There may be a combination of medications prescribed by your veterinarian to help your dog feel better.

The following are some examples of medications used:

• Fenbendazole
• Metronidazole
• High-digestible diet
• Supplemental therapy

Following up with your veterinarian after treatment is important to determine whether or not treatment was successful. Often this is done by checking another fecal sample.

Is Giardia contagious in dogs?

Any dog can get giardia from water or food that has been contaminated with fecal matter.

For example, “We see Giardia pet claims often, it’s in the top 40 most commonly claimed conditions for dogs,” says Malia Prescott, Trupanion Data Analyst.

You also need to be aware that if your dog has giardia, it can spread to another pet in your home. While cross-species infections are uncommon they can happen. Consider proper handwashing and being extra careful when handling your dog’s poop.

How to prevent Giardia in dogs

While the condition is not typically life-threatening, it may cause incredible discomfort for your dog. As such, you need to prevent it where possible.

Before you take your dog for a walk make sure they’ve had plenty of water or consider bringing water from home for them to drink. Also, be mindful of your dog while they’re outside. Puppies love picking up items off the ground, so basic training can come in handy to avoid any surprises.

For example, commands like “leave it” can be helpful when trying to train your puppy to leave items on the ground or floor. You never know when a command like that may come in handy.

Lastly, always clean up after your pet on a walk and be mindful of grassy areas where there are a lot of dogs.

Check out this FAQ for more information on Giardia:

• Is there a Giardia vaccine for dogs? This vaccine was available and was created to help fight the effects of the parasite. Also, it has not been shown to prevent infection and is not recommended by the AAHA. The manufacture of the vaccine has been discontinued.


• What kills Giardia on surfaces? The best solution for use on surfaces is a mixture of bleach and water.


• How to get rid of Giardia in your yard? Remove waste from your yard, remove standing water, and limit your pet’s use of public outdoor spaces. Consider keeping other animals out of your yard.

How long does Giardia last in dogs?

While senior dogs and puppies may respond differently to treatment, typically most cases of giardia should only last a few weeks.

The takeaway

Giardia is common, but can be treated. By talking with your veterinarian, staying on the treatment plan, and monitoring your pet, they should be back to play in no time at all.

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