Efficacy of Afoxolaner Alone or in Combination with Milbemycin Oxime against <i>Rhipicephalus sanguineus</i> Lato Sensu in Naturally Infested Dogs in Colombia

The brown dog tick (Rhipicephalus sanguineus lato sensu) is the that most affects dogs worldwide and therefore main blood pathogen vector in dogs. efficacy of afoxolaner 2.7 to 7.1 mg/kg NexGard® (group A) plus milbemycin oxime 2.5 5.4 0.5 1.1 respectively NexGard Spectra® (Group B) against R. sanguineus, was evaluated naturally infected sheltered under high challenging conditions four different areas Colombia (Antioquia, Córdoba, Santander, Meta). Tick counts (alive, dead, attached, unattached) were performed on treated dogs, average calculated for evaluate each treatment at six times post-treatment (24 h, 48 7 d, 14 21 30 d). None showed adverse events related treatments. number pre-treatment 68 group A 78.3 B indicating a strong natural infection their environment. Efficacy after 24 h always above 90% with ≥97.4% ≥93.7% Spectra®. Consistent results observed along all observation periods final efficacies (day 30) ≥99.8% 98.3% Spectra®, respectively. In conclusion, both Nexgard provided curative effect sustained Rhipicephalus least days highly contaminated shelter environments.