Objective—To determine efficacy of treatment with a combination febantel-praziquantel-pyrantel product, with or without vaccination with a commercial Giardia vaccine, in dogs with naturally occurring giardiasis.
Animals—16 Beagles naturally infected with Giardia duodenalis.
Procedures—During phase 1, 6 dogs were treated with the parasiticide for 3 days (4 were also vaccinated). Four weeks later, all 6 dogs were treated with the parasiticide again for 5 days and were bathed and moved to clean cages after the last treatment (phase 2). Nine dogs were treated with the parasiticide for 3 (n = 4) or 5 (5) days and bathed and moved to clean cages after the last treatment (phase 3). Fecal samples were collected twice weekly for 24 days after treatment and tested for cysts with a quantitative zinc sulfate flotation technique and for Giardia antigen with an immunoassay.
Results—Dogs in phase 1 were all shedding cysts again by day 24. In phase 2, only 1 dog shed cysts after treatment, and shedding was transient (day 17). In phase 3, neither cysts nor antigen was detected in fecal samples from 2 of 4 dogs treated for 3 days and 4 of 5 dogs treated for 5 days. In 18 of 57 (31.6%) fecal samples, cysts were seen, but results of the immunoassay were negative.
Conclusions and Clinical Relevance—Results suggest that when a combination febantel-praziquantelpyrantel product is used to treat dogs with giardiasis, bathing and changing the environment after treatment may be more important in preventing recurrence than duration of treatment. (J Am Vet Med Assoc 2002;220:330–333)