Giardia is a common and frequent problem that we face here in the Pacific Northwest. What is the prognosis for Giardiasis?
The prognosis is good in most cases. Debilitated or geriatric animals and those with incompetent immune systems are at increased risk for complications, including death. All pets diagnosed with Giardia should be re-tested two to four weeks after completion of treatment.
Can my dog give a Giardia infection to me or my family?
Giardia can cause diarrhea in humans and can potentially be passed from dogs to humans. In the past, it was assumed that cats and dogs, along with wildlife, were an important source of infection for humans. Genotypes or Assemblage A can infect humans, dogs and cats while B can infect both humans and dogs.
“…contaminated municipal water supplies are responsible for many outbreaks.”

If your dog is diagnosed with giardiasis, environmental disinfection and good personal hygiene are important to prevent accidental spread to humans. In particular, people with immunodeficiency, such as AIDS or cancer, or who are undergoing chemotherapy, should use extreme care, especially when handling feces or after administering medications.
For environmental disinfection, you can use chlorine bleach at 1:32 or 1:16 dilutions, or 1-2 cups in a gallon of water (60-120 ml/L). However, be sure that the affected surfaces can be safely treated with bleach. Lysol® and quaternary ammonium compounds (Parvosol®, etc.) are also reported to be effective in killing the cysts. Giardia cysts are susceptible to drying so try to keep your environment as dry as possible. For best results, thoroughly clean the pet’s living and sleeping areas and then allow the areas to dry out for several days before reintroducing pets.
This client information sheet is based on material written by: Ernest Ward, DVM. Updated by Robin Downing, DVM, DAAPM, DACVSMR, CVPP
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