Can Dogs Get Giardia?

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The five most common parasites that infect dogs include hookworms, roundworms, whipworms, tapeworms, and giardia. Unlike the other parasites, however, giardia is not a worm, but a one-celled protozoan parasite. It may also be referred to as giardia intestinalis, as it is a common parasite that infects the gastrointestinal tract in your dog.

Is it worth worrying about? How can you prevent it?

Let’s take a closer look into canine giardia, giardia symptoms in dogs, and how to treat giardia in dogs down below. By the end, you can better ensure your dog is healthy and parasite-free.

Can Dogs Get Giardia?

Giardia is, unfortunately, rather common all throughout the U.S., and your dog may be susceptible to becoming infected at any time of year.

How Do Dogs Get Giardia?

The lifecycle of giardia is comprised of two stages—cysts and the matured trophozoites. Cysts are arguably the more harmful stage, due to the fact that they can survive for months, no matter the conditions. While other parasites tend to die off in the winter, giardia actually thrive in the cold.

Cysts are shed along with the infected animal’s feces, meaning they have a better chance of spreading to other animals – and multiplying within your infected dog. For example, if the feces are then ingested by your unsuspecting dog, the cysts then mature into trophozoites in the dog’s gastrointestinal tract and produce even more cysts to continue the cycle all over again.

Even the slightest brush with infected fecal matter could mean a possible giardia infestation. One of the most common infection methods is by drinking contaminated water. Of course, dogs may also become infected by directly eating contaminated feces.

Unfortunately, you are more likely to find giardia in puppies and those confined in tight quarters, such as kennels or boarding facilities. This is because they are more likely to come into contact with infected fecal material.

While humans can also become infected, you usually do not have to worry about contracting a giardia infection from your pets alone. The type of giardia that infects humans is not the same kind that infests dogs and cats, and vice versa.

Giardia in dogs

Symptoms of Giardia in Dogs

Between 6 to 7 percent of all dogs can be infected with giardia at any given time, and about 8 out of 10 of these cases will surprisingly show no symptoms whatsoever!

Until only a few years ago, giardiasis (or the disease associated with a giardia infection) was thought to be rather uncommon in dogs, so most veterinarians will likely gloss over this parasite as a possible cause for any health problems your dog may have later.

It is always a good idea to ask your veterinarian to test for it if you suspect this is the case.

Diarrhea and Weight Loss

The most common symptoms of giardiasis include diarrhea and weight loss. This is because the parasites inside your dog’s intestines will hinder your dog’s body’s ability to absorb the nutrients, water, and electrolytes they take in. Instead, the parasites will use it to sustain themselves.

Your dog’s diarrhea can be either intermittent, meaning they may have it off and on, or continual. Puppies are more likely to suffer from continuous diarrhea due to giardia than older dogs.

Additionally, their stool will stink more than usual and may even contain mucus, regardless if it is loose or fully formed.

Diarrhea is also a general sign of malabsorbed nutrients, which can lead to muscle-wasting. This is basically when your dog will suddenly lose a great deal of weight despite eating the usual amount (or even less) of food you give them.

This can last for months at a time if left untreated, so again, it is important for you to take your dog to see your veterinarian if they pass any diarrhea for more than a few days. Failure to diagnose and treat giardiasis in a timely manner can lead to severe weight loss, malnutrition, and even death in extreme cases. As such, the disease is especially dangerous for puppies, senior dogs, and dogs with compromised immune systems.

Canine giardia

Vomiting, Bad Breath, And Dehydration

Dogs may vomit either intermittently or continuously if they have contracted giardia. Of course, this may be a general sign that they’ve eaten something rotten or contracted other illness. However, if this vomiting is accompanied by diarrhea or weight loss, then you should take your dog to the veterinarian immediately.

This constant vomiting can also lead to bad breath. Foul breath is not usually a symptom of giardia (or infection in general), and veterinarians may simply attribute it to being an oral issue instead. Many dogs suffer from chronic halitosis, leading people to believe that all dogs just naturally have bad breath.

However, if your dog is on a raw food diet and has healthy teeth and gums, then their bad breath may be a sign of a more serious problem. Do not overlook the smell of your dog’s breath if they happen to be on such a diet. Many owners report dogs on this diet normally having sweet-smelling breath, so any foul odors could mean there is something wrong with their digestive system.

Vomiting (whether accompanied by diarrhea or not) can also lead to dehydration, which, in turn, can cause nausea and even more vomiting or diarrhea.

While giardia infections are not typically life-threatening, the dangers these symptoms pose can be – if left untreated. You should take your dog to the veterinarian before it even reaches this point.

Giardia treatment in dogs

Other Giardia Symptoms

There are many lesser symptoms of giardia in dogs that owners should be aware of. Nonetheless, it’s worth noting that they’re not exclusive to giardiasis, and do not always occur if a dog has a giardia infection.

Giardia may not only absorb the nutrients from your dog’s ingested food and water, but also the nutritional supplements they take. Dogs who already struggle with autoimmune diseases will ultimately suffer more from this infection than other dogs.

You may also notice that their coats have lost a healthy glow or that they appear to suffer from abdominal pain as well.

When to See Your Vet

All dogs, no matter how healthy they may seem, should have at least a few fecal samples tested every year to ensure they do not have any gastrointestinal parasites. Not all dogs with giardia will display the symptoms listed above, making this test extra important.

If you notice your dog vomiting or passing a great deal of diarrhea, you definitely need to take them to your veterinarian.

All newly adopted puppies, dogs or, any dogs you have kept in high-risk environments such as a kennel, dog show, or boarding facility should be tested for parasites before you bring them home.

Giardia symptoms in dogs

Giardia Treatment in Dogs

While giardia is normally undetected by routine fecal examinations and other similar tests, there are certain tests you can ask your veterinarian to run, just to make sure your dog doesn’t have this infection.

These tests will have varying levels of accuracy, and may even need to be repeated up to three times to be sure your dog has not contracted giardia. Just keep in mind these tests should not replace your veterinarian’s routine stool checks.

The ELISA Test

This test is one of the most reliable ones in detecting giardiasis, and will most likely display correct results the first time around. The ELISA test for giardia will unfortunately not be able to detect other parasites or problems that your dog may have on top of giardiasis. So, keep this in mind if you want a test that screens a wider array of health issues.

Your dog must be taken to a separate lab to undergo this test.

The Float Test

Though this test is designed to look for worms, many technicians who are specifically trained to find giardia often find it far better at detecting cysts than other tests. This test will typically be performed in-clinic.

The Fecal Smear

This test looks at a sample of your dog’s feces to detect any trophozoites before they die off. It is not that effective in detecting cysts, though your veterinarian may uncover a few regardless.

This test is typically performed in-clinic.

The Fluorescent Antibody Test (FAb)

While this test is generally more reliable than the fecal smear, it’s also known to give both false positives and/or negatives, making it the least reliable giardia test.

These tests are typically run in a special lab.

Giardia in puppies


Both fenbendazole and metronidazole are the most common drugs used to kill off a giardia infection. Both drugs may be prescribed at once if the infection is particularly rampant or if your dogs has refractory diarrhea (or diarrhea that has not responded well to a previous treatment).

Typically, you only need to administer these medications for three to ten days at the most. However, your veterinarian may also prescribe additional drugs as a supplemental therapy if your dog also suffers from dehydration or severe diarrhea.


Fenbendazole is very effective at removing cysts from your dog’s feces, if given the right dosage for at least five days or more. There are no adverse side effects to taking this drug, making it the safest medication for both pregnant and lactating animals.

Unfortunately, this medication is unsafe for cats, so your veterinarian may instead prescribe your pets metronidazole instead.


Metronidazole is approximately 65 percent effective in eliminating giardia cysts and trophozoites from your pets’ intestinal tracts. Because metronidazole benzoate is safer for cats, many veterinarians will prescribe this medication if they know you own both cats and dogs.

Unfortunately, side effects of this medication may include an acute development of anorexia and even more vomiting, which may later progress to pronounced generalized ataxia and vertical positional nystagmus.

How do dogs get giardia

Both Fenbendazole and Metronidazole

If your veterinarian prescribes both medications, then they may instruct you to first give your pets fenbendazole for five to ten days, and then metronidazole for another five to ten days. They may also advise you to simply give your pets both medications together for five days if you are unable to parse them out.

If their giardiasis has not lessened by this time and your veterinarian still finds cysts in their feces, they may then ask you to continue this combination therapy for another ten days.

Depending on your dog’s condition, as well as the severity of their infection when you first brought them to be checked out, your veterinarian may also require a couple follow-up tests and treatments within two to four weeks of treatment application.

Bathe Your Dog

You should bathe each pet you own on their last day of treatment to ensure their coats are free of any stubborn giardia cysts. Be sure you wear gloves as you bathe them, and always clean their back end last.

First, you should bathe their body as you normally would, then focus your attention on thoroughly cleaning their anus to ensure any cysts stuck around it rinse off. Do your best not to touch any other part of their body after you are done. Otherwise, you may accidentally spread them.

Disinfect Potentially Contaminated Items

You must also regularly disinfect any items your pet has come into contact with in either boiling water or in a high-temperature dishwasher. Such items may include:

  • Toys.
  • Water and food bowls.
  • Pet bedding.
  • Dog crates.
  • Linens.
  • Towels.
  • Litter boxes.

Any upholstery or carpeting they touch should also be steam-cleaned and allowed to dry. Any hard surfaces, such as tile or wood, should be disinfected with a pet-safe household cleaning product as well.


Canine giardia can be an unpleasant parasitic infection for both you and your dog to deal with.

Accounting for such elusive symptoms and dismissive veterinarians, it can be frustrating to know if your dog truly has giardiasis or not. Luckily, there are specialized tests you can ask your veterinarian to perform to receive a proper diagnosis.

By administering the right medications and regularly disinfecting and cleaning your home, this parasitic infection should clear up in just a few weeks.

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