The Challenges with Canine Giardia

Abstract

This chapter reviews the prevalence of Giardia and Giardia Assemblages in people and dogs and the risks that dogs may present as sources of human infection. The review shows that the treatment of dogs with any of the currently available therapeutics given to dogs often do not clear all Giardia from dogs or halt Giardia from repopulating a negative. Humans sometimes host Giardia that is very difficult to clear with therapy. The concern is expressed that the treatment of dogs without clinical signs repeatedly with drugs that are less than perfect is likely selecting for Giardia that will be resistant to treatment remaining in the treated dogs and potentially shared with other dogs. If transmission is occurring in people that comes from dogs and if it is demonstrated that people are infected with resistant canine isolates, it will have a negative impact on the human–animal bond. Therefore, it is suggested that veterinarians give careful consideration to the perceived need to treat all dogs testing positive for Giardia, because it may in the end have serious impacts on the relationship between pet owners, their dogs, veterinarians, and the practitioners of human medicine.