Objective—To determine whether an amitraz-impregnated
collar could prevent transmission of Borrelia
burgdorferi by Ixodes scapularis to dogs.
Animals—8 specific-pathogen-free Beagles.
Procedure—On days –15 and –1, all dogs had negative
ELISA results for serum antibodies against B
burgdorferi. On day 0, 4 dogs were each fitted with an
amitraz-impregnated (9%) collar, and 4 dogs served
as untreated controls. On day 7, all dogs were infested
with 100 I scapularis (approx 50 females and 50
males) with a known B burgdorferi infectivity rate of
39.4%. On days 21, 28, 35, 42, 56, 70, and 84, each
dog was tested for serum antibodies against B
burgdorferi via ELISA and a western blot technique.
Additional ELISA were also performed for serum antibodies
against antigenically similar organisms.
Results—By day 70, all control dogs had developed
serum ELISA responses ranging from 328 to 510
kinetics-ELISA units (equivalent to end-point titers of
approx 43,500 to 60,000), whereas treated dogs
remained seronegative throughout the study.
Western blot assays performed on all serum samples
confirmed that antibodies detected in control dogs
reflected responses to specific antigens of B burgdorferi,
whereas treated dogs had no such antibodies.
Additional serologic analyses confirmed that antibody
responses observed in control dogs were not attributable
to antigenically similar organisms.
Conclusions and Clinical Relevance—Amitrazimpregnated
collars prevented transmission of B
burgdorferi in 4 of 4 treated dogs and may be a useful
management tool for prevention of borreliosis in
dogs. (J Am Vet Med Assoc 2001;219:185–189)