A novel combination of fipronil and permethrin (Frontline Tri-Act®/Frontect®) reduces risk of transmission of Babesia canis by Dermacentor reticulatus and of Ehrlichia canis by Rhipicephalus sanguineus ticks to dogs

摘要

BACKGROUND : The ability of Frontline Tri-Act®/Frontect®, a topical ectoparasiticide containing fipronil and permethrinfor dogs, to prevent the transmission of Babesia canis as well as Ehrlichia canis was evaluated by infesting dogs withinfected vector ticks.METHODS : For the Babesia canis study, 16 dogs were randomly allocated to two groups. Eight dogs were treated onday 0 with a topical spot-on formulation containing 6.76 % w/v fipronil plus 50.48 % w/v permethrin and eight dogsserved as the untreated control group. Dermacentor reticulatus ticks, with a B. canis infection rate ranging between2 and 10 %, were placed onto dogs on days 7, 14, 21 and 28. In situ tick counts were performed on Days 9, 16 and23. Ticks were counted and removed on Day 30. Infection of the dogs with B. canis was monitored by rectal temperaturereadings, clinical examinations and blood smears as well as PCR and IFA (indirect fluorescent antibody assay).For the Ehrlichia canis study, another 16 dogs were allocated to two groups. Eight dogs were treated with the fipronil andpermethrin combination on days 0 and 28 and eight dogs served as untreated controls. Rhipicephalus sanguineus ticks,carrying an infection rate of 13 % for E. canis, were released in the sleeping kennels of the dogs on days 7, 14, 21, 28, 35,42, 49 and 56. Ticks were counted in situ on the dogs on a weekly basis. All ticks were removed and counted on the finalassessment day 58. Infection of the dogs with E. canis was monitored by rectal temperature, clinical examinations, andtesting of blood samples by PCR, IFA and platelet counts.RESULTS : B. canis was transmitted by D. reticulatus ticks to all eight untreated control dogs and to one treated dog, whichwas confirmed by blood smears, PCR and IFA. E.canis was transmitted by R. sanguineus ticks to all eight untreated controldogs. Two of the dogs in the treated group were found positive based on PCR and/or IFA.CONCLUSIONS : Frontline Tri-Act®/Frontect® significantly lowered the risk for dogs to acquire a B. canis infection by 87.5 %over a challenge period of 28 days. The risk for dogs to acquire E. canis was reduced by 75 % over a period of 56 days.