Efficacy of fenbendazole in the treatment of experimental Giardia infection in dogs

Abstract

SUMMARY: Objective: To evaluate the efficacy of fenbendazole as a treatment for Giardia sp. Animals: 10 male and 10 female commercial-source Beagles. Procedure: The experiment was conducted in 2 replicates. Dogs considered free of Giardia infection on the basis of results of 3 consecutive negative fecal examinations were experimentally infected with approximately 1,000 Giardia cysts isolated from dog feces. After verification of infection, the dogs were allocated to 2 groups (treated and untreated) and were housed in separate rooms. Treated dogs received 50 mg of fenbendazole/kg of body weight, PO, daily, for 3 days. After treatment on the third day, treated dogs were removed from their runs, shampooed, rinsed with disinfectant, and returned to disinfected runs. Fecal samples were collected from all dogs 12 times during the next 25 days. Results: Giardia cysts were found in the feces of every untreated dog during all or part of the test period. Nine of 10 treated dogs did not have Giardia cysts in any fecal sample examined; the other dog had a positive result on a single sample in the third week after treatment. Conclusion and Clinical Relevance: Fenbendazole, at the nematocidal label dosage, is an effective drug for treatment of Giardia infection in dogs. (Am J Vet Res 1998;59:61–63)