Can Dogs Get Giardia?

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A dose of giardia is one vacation souvenir you really don't want to bring home!

Also known as 'Traveler's diarrhea', this unpleasant single-celled parasite causes diarrhea, flatulence, nausea, and weight loss in people.  

Humans are usually infected through contact with infected water or food touched with contaminated hands. Yewh! This is because giardia cysts are passed out in feces and are particularly hardy. When personal hygiene is poor, dirty hands easily transfer the bug onto whatever food, crockery, or cutlery is being handled.

Traveler’s diarrhea is unpleasant, to say the least. It tends to run on (excuse the pun) for weeks, and often needs medication to get it to settle. But if you have a persistently upset tummy or have been diagnosed with giardia, can you pass it on to your dog?

Can Dogs Get Giardia?
YES!

Actually, things are a more complicated than a straight "Yes". There is no doubt that dogs get giardia, but what's in question is how much of a risk people are to dogs or vice versa.

As with so many infections, most bugs are species-specific. With Giardia infections, things aren't clear cut, but it's thought cross-species transmission is possible, but over-diagnosed since most of the strains prefer either people or dogs.

However, why take a risk? Washing hands after visiting the restroom and before eating goes a long way to keeping everyone (two and four-legged) healthy.

Does My Dog Have Giardia?

This is a great question! Many, many dogs do have Giardia but aren't sick (an important difference with people!). Thus, a great many cases are picked up 'accidentally' during fecal screenings. This then raises a question about whether 'well' dogs be treated or not, since this could, in theory, induce medication resistance.

However, some dogs are most definitely sick with Giardia. These guys tend to be those who are very young, elderly, or have a health problem. The key to this is their immune system is weaker, and not so good at fighting the bug. Signs include:

  • Persistent foul diarrhea

  • Flatulence

  • Poor growth

  • Weight loss

  • Intermittent sickness

  • Stomach ache

Diagnosis is made by analyzing a sample of the dog's feces, alongside ruling out other possible causes of a stomach upset.  To learn more about this, run over to Giardia in Dogs .

How Do I Treat My Dog's Giardia?

Another great question!

There is a strong argument that dogs’ whose Giardia was detected on a routine screening should not be treated. This is because they aren't ill and using medication risks inducing resistance to the treatment.

For those dogs that do require treatment, this is usually fenbendazole or metronidazole. The length of the course varies between 3 and 10 days, and some vets recheck the feces at the end of therapy.

Hygiene is also important. Bathing the dog regularly gets rid of giardia soiling the coat, reducing the risk of self-reinfection. On a theme, it's also best to disinfect the pet's bed and crate, and steam clean carpets, food bowls and so forth.


If you are uncertain how to care for a dog with giardia, pop over to our guide to Giardia , where you can also ask the advice of our in-house vet.

How is Giardia Similar in Dogs and Humans?

People and dogs have a lot in common when it comes to giardia:

  • Diarrhea: This is unpleasant and linked to stomach cramps

  • Contaminated water: Both people and dogs pick up infection from contaminated food or water

  • Those at risk: Those most likely to become sick are the very young, elderly, or with an existing health problem.

How is Giardia Different in Dogs and Humans?

Perhaps the most major difference is how common Giardia is in dogs that don't show symptoms. A dog's love of scavenging and foraging places him at greater risk of contracting giardia, and yet a healthy immune system seems to protect from clinical illness.

It's also not clear how much of a risk dogs are to people, and vice versa. Of course, good hygiene is essential regardless of what bugs are involved, and everyone is well advised to wash their hands before putting anything in their mouth.

Case Study

Ziggy the dog enjoys hiking with his owner, digging in mud, and eating what he shouldn't. Shortly after his return from a weekend away, Ziggy develops offensive smelling diarrhea. His owner tries the usual tricks of fasting his dog, but nothing seems to help.

After several days of digestive upset, Ziggy's owner takes him to the vet.  Blood tests show Ziggy to be the picture of health...apart from his digestive disturbance. However, a fecal sample shows a large population of Giardia cysts.

Given Ziggy's love of mud and the sudden onset of his symptoms, it is decided to trial him with treatment. After 10 days on treatment, bathing Ziggy, and a spring clean, the problem has happily resolved. Ziggy, however, remains as determined as ever to dig in the
mud.