Giardia in Dogs

While most dogs and puppies recover from giardiasis with treatment, the infection can kill a dog with a compromised immune system or who is already in poor condition. Some dogs become permanent carriers of the protozoa causing the disease. People can also become infected with Giardia, although it's usually contracted from other humans, not canines.



Giardiasis occurs when a dog becomes infected with Giardia, a one-celled protozoan. Dogs and puppies contract giardiasis by ingesting the cysts, or Giardia "offspring," when coming into contact with contaminated feces. Giardia is often present in environments containing a lot of dogs, including kennels, shelters and pet shops. The infection is quite common. The Companion Animal Parasite Council notes that while regional differences exist, infections with clinical signs in canines average 15.6 percent.


Puppies or dogs with giardiasis experience vomiting and diarrhea, along with excess gas and weight loss. Dogs suffering from giardiasis might produce extremely bad-smelling feces containing mucus. Many dogs with Giardia in their intestinal tracts show no symptoms, but shed the cysts in their feces. Your vet diagnoses the presence of Giardia in a dog's stool by analyzing a fecal sample for the cysts.


Your vet will prescribe medications to combat the Giardia, including antibiotics and dewormers. She might also recommend a high-fiber diet to firm up feces, as well as a shampoo for your dog to remove cysts on the coat. Relatively healthy dogs generally respond to this treatment, although it can require several followup visits to the vet for fecal testing and perhaps more than one round of antibiotics to get rid of the parasites.

Chronic Giardiasis

In a small percentage of dogs, the giardiasis can't be completely eradicated after numerous rounds of antibiotics. These dogs might suffer from chronic malabsorption, in which nutrients from their food can't be properly utilized by the body. These dogs often exhibit weight loss and loose bowels. Dogs with chronic giardiasis, even if appearing quite healthy, carry the parasite and can infect other animals who come into contact with their feces. If your dog is a carrier, it's important to clean up all fecal material immediately and keep the dog's environment disinfected. If you have other dogs or cats, take fecal samples to the vet regularly for Giardia testing.

By Jane Meggitt

About the Author
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.