Influência do nível de desafio populacional de Ctenocephalides felis felis sobre a eficácia do fipronil em Cães. 2013.

Abstract

The objective of the present study was to evaluate the influence the level of of population challenge of Ctenocephalides felis felis on the efficacy of fipronil 10% “topspot” in dogs. For this, 24 Beagles were used, divided into four groups of six dogs each. The dogs on the control groups I and II were not treated, while the dogs on the treated group I e II were treated with the formulation of 10% fipronil ‘‘topspot’’. The dogs in the control group I and treated group I were infested with 50 pairs of C. felis felis and dogs in groups control II and treated II were infested with 150 pairs of C. felis felis each. Infestations were performed on days 2, +5, +12, +19, +26, +33 and +40 and on days +2, +7, +14, +21, +28, +35 and +42 fleas were mechanical removed and counted for evaluation. Pulicide efficacy for treated group I on days +2, +7, +14, +21, +28, +35 and +42, were respectively 99.36%, 99.73%, 99.48%, 99.00%, 74.00%, 99.75%, 95.06% and 67.62%. The pulicide efficacy for the treated group II, evaluated on the same days, were respectively 100%, 100%, 100%, 100%, 99.91, 95.60% and 68.55%. Fipronil was effective in eliminating fleas on dogs until day +35. The statistical comparisons between the mean living fleas between groups control I and treated I showed significant differences (p ≤ 0.05) for the challenges in all experimental days after treatment. Groups control II and treated II also showed significant differences (p ≤ 0.05) for the challenges in all experimental days after treatment. Statistical analysis between treated groups I and II showed no significant difference (p ≥ 0.05) between the challenges in all experimental days. The challenges were finished on day 42, when the effectiveness of fipronil in treated groups I and II were lower than 70%. The tested product was effective in eliminating fleas on dogs until day + 35 with no more residual effect of protection when the animals were reinfested. Different level of exposure of populations of C. felis felis, 100 and 300 exemplary, through weekly infestations were not able to determine different fipronil efficacy responses, when used in dogs.