If your dog has recently suffered from diarrhea, appetite loss, or vomiting, they may have an intestinal parasite infection. One common intestinal parasite—Giardia—is in a class of its own, and is more difficult to prevent, manage, and treat. This protozoan parasite differs from the roundworms and tapeworms that most pet owners are familiar with, but understanding how dogs can contract this parasite, and the treatment, is vital. Our Columbia Pike Animal Hospital team shares the scoop on this parasite found in your pet’s poop.

What is Giardia?

Giardia is a sneaky parasite that lurks in a variety of places, waiting to infect your pet or wildlife—or you. This microscopic organism exists in two stages:

  • A fragile, active form called a trophozoite—infection develops during this stage
  • A hardy, dormant form, known as a cyst, that is responsible for transmission

Giardia is typically transmitted through contact with cyst-contaminated water, food, stool, or surfaces, so good hygiene is critical for preventing the parasite from spreading.

How can my dog contract Giardia?

Giardia can infect your dog in several ways. Causes of giardiasis in dogs include:

  • Contaminated water or soil — One of the most common ways dogs—and people—become infected with Giardia is by drinking from contaminated puddles, stagnant ponds, or other water bodies. Your dog can also be infected after digging in contaminated soil and ingesting cysts.
  • Contact with infected dogs — Playing with an infected dog may lead to transmission, especially from an infected dog who greets your pet by sniffing their hind end.
  • Poor hygiene — Poor hygiene can cause parasite transmission. Your dog can be infected if they lick their paws after walking in a feces-laden dog park or visiting a dirty pet store.
  • Weakened immune system — Healthy dogs more likely can fight off Giardia and prevent infection. Young, old, or immunocompromised pets are at an increased risk for developing giardiasis.

What signs will I see if my dog has Giardia?

Giardiasis can manifest differently in affected dogs. Some pets may show no signs, while others can develop:

  • Foul-smelling, greasy, pale diarrhea
  • Vomiting
  • Lethargy
  • Weight loss
  • Poor coat quality
  • Decreased appetite
  • Dehydration

Dogs with giardiasis can show clinical signs that wax and wane, and may have chronic soft stool that firms up for a while, only to become loose again.

How will my veterinarian diagnose giardiasis in my dog?

Diagnosing giardiasis can be challenging, as infected pets shed cysts intermittently. Cyst identification on a fecal exam is the primary diagnostic method, although rarely, spotting trophozoites can also lead to a diagnosis. 

If your dog shows clinical signs consistent with giardiasis, but no cysts are seen on their fecal exam, additional testing may be recommended. For example, Giardia antigens in a stool sample can provide an accurate diagnosis.

How will my veterinarian treat giardiasis in my dog?

If your dog has giardiasis, you must complete the full treatment course to eliminate parasites. Treatment generally consists of a deworming medication, antibiotics, and a bland diet, plus bathing your dog and washing their bedding once treatment is completed, to remove all Giardia organisms.

Can I get Giardia from my dog?

While giardiasis is technically a zoonotic infection, the Giardia types that most commonly infect dogs are content with their canine hosts and rarely transfer to people. However, dog-to-person transmission, while uncommon, can happen, so always practice good hygiene when dealing with your dog with giardiasis.

Can I prevent my dog from getting Giardia?

You can prevent your dog from developing giardiasis by:

  • Providing fresh water — Always provide your dog with fresh drinking water so they don’t turn to dirty, contaminated water.
  • Avoid standing water — Keep your dog out of stagnant puddles and ponds that most likely are Giardia reservoirs.
  • Practice proper hygiene — Good hygiene practices are essential for preventing not only giardiasis, but also a multitude of other infectious parasites and diseases. Clean up your dog’s feces immediately, and wash your hands thoroughly.
  • Designate a bathroom area — Since Giardia organisms are immediately infective the minute they reach the ground, block off a specific area of your yard for your dog’s bathroom facilities. Confine your dog to this area during their giardiasis treatment and then avoid the area to prevent reinfection.

If your dog develops concerning gastrointestinal signs, they may have giardiasis. Any diarrhea case, especially one that does not resolve on its own, is cause for concern, so contact our Columbia Pike Animal Hospital team for an appointment for your pooch.