Oral Efficacy of Fipronil in the control of Ctenocephalides felis felis (Siphonaptera: Pulicidae) and Rhipicephalus sanguineus (Acari: Ixodidae) in dogs
ABSTRACT. Melo R.M.P.S., Vieira V.P.C., Tavares P.V., Batista L.C.S.O., Carneiro M.B., Correia T.R., Cid Y.P., Coumendouros K. & Scott F.B. [Oral Efficacy of Fipronil in the control of Ctenocephalides felis felis (Siphonaptera: Pulicidae) and Rhipicephalus sanguineus (Acari: Ixodidae) in dogs]. Eficácia oral do fipronil no controle de Ctenocephalides felis felis (Siphonaptera: Pulicidae) e Rhipicephalus sanguineus (Acari: Ixodidae) em cães. Revista Brasileira de Medicina Veterinária 34(Supl. 1):15-20, 2012. Departamento de Zootecnia, Universidade Federal de São João Del Rei (UFSJ), Rodovia BR 494, Km 2, São João Del Rei, MG 36300-000, Brazil. E-mail: firstname.lastname@example.org Fipronil has been used worldwide by topic application for control of Ctenocephalides felis felis and Rhipicephalus sanguineus. The efficacy of fipronil administered orally was evaluated against C. felis felis and R. sanguineus in artificially infested dogs. Twenty four Beagle dogs were divided in three treated groups, which received fipronil in gelatin capsules at single oral doses of 2.4 and 6 mg.kg-1 of body weight on day 0, the fourth group was kept as non medicated control. Dogs were infested weekly with 100 fleas and 50 ticks, two days before each assessment. The evaluations were done weekly, counting fleas and ticks using the comb test method, on days +2, +7, +14 and +21. The efficacy data registered for flea control using 2 mg.kg-1 were 100% on day +2 and 83.79% on day +7. Dogs treated with 4 mg.kg-1 showed reductions of 88.34 for day +2 and 67.98% for day +7. Data related to days 14 and 21 for both groups were lower than 60%. Efficacy on animals treated with fipronil at 6 mg.kg-1 orally was 97.88, 95.27, 88.75 and 71.43% on days +2, +7, +14 and +21, respectively. Very low efficacy results were registered against ticks, R. sanguineus: fipronil orally at 2 mg.kg-1 exhibited ef ficacy of 25.35% and 0, dogs treated with 4 mg.kg-1 orally, 29.58% and 0, and animals treated with 6 mg.kg-1 the efficacy were 43.67 and 23.28%, respectively, on days +2 and +7. The data showed that oral administration of 6 mg.kg-1 of fipronil can be effective in controlling flea infestation by C. felis felis in dogs up 14 days, but it is not effective in control of R. sanguineus in dogs.