Managing Giardia: Combination of Drugs & Disinfectants?

Giardia canis can be difficult to eliminate, especially in group housing. In this study, researchers tested a disinfection protocol in combination with drug treatment to control an outbreak in a dog kennel. The experimental group included 6 infected dogs housed as a group in a large kennel. Treatment for this group began with shampooing each dog with a product containing chlorhexidine and oral treatment with ronidazole (30–50 mg/kg PO q12h for 7 days). Each enclosure was disinfected with 4-chlorine-M-cresol. Treatment protocols were repeated on day 6 of the study, and daily cleaning with standard agents occurred on all other days. The control group contained 7 dogs and received only standard cleaning treatment (ie, without ronidazole) until day 47, when both groups received the same enclosure disinfection and bathing protocols. At this time, ronidazole treatment was administered to the control group. Dogs in the experimental group tested negative for Giardia cysts and antigen up to 26 days after the final ronidazole treatment, while at least 1 (and up to 5) in the control group tested positive throughout the study.

CommentaryBecause G canis spreads in loose diarrheal feces and its cyst stage is highly resistant to environmental conditions, infection can spread rapidly and is hard to contain. Ronidazole is currently used to treat Tritrichomonas foetus infection in cats, but this study also demonstrated its efficacy as a treatment for giardiasis. When combined with diligence in cleaning and disinfection, G canis outbreaks can be effectively managed, even in a large group setting.—Carly Jordan, PhD

SourceControl of Giardia infections with ronidazole and intensive hygiene management in a dog kennel. Fiechter R, Deplazes P, Schnyder M. VET PARASITOL 187:93-98, 2012.