Comparative efficacy of two oral treatments for dogs containing either afoxolaner or fluralaner against Rhipicephalus sanguineus sensu lato and Dermacentor reticulatus

- Afoxolaner (NexGard®) and fluralaner (Bravecto™) are two new ectoparasiticides from the class isoxazolines.
- Afoxolaner and fluralaner act systemically due to their binding on plasma protein.
- Fluralaner is administered at a minimum dose of 25 mg/kg to provide 12 weeks of efficacy while afoxolaner is administered at 2.5 mg/kg to provide 5 weeks of efficacy.
- The speed of efficacy on ticks should be more regular following monthly administration of afoxolaner than a single administration of fluralaner.

The present study compares the efficacy of two recent oral ectoparasiticides containing isoxazolines (NexGard®, containing afoxolaner and administered at a monthly regimen, and Bravecto™ containing fluralaner and administered at a tri-monthly regimen) against Rhipicephalus sanguineus sensu lato and Dermacentor reticulatus ticks on dogs.24 dogs were randomly allocated to untreated control, NexGard® treated, and Bravecto™ treated groups. The treatments were administered on Days 0, 28 and 56 for afoxolaner and on Day 0 for fluralaner. Tick infestations were performed weekly with 50 unfed adult ticks per each species on each dog from Days 30 to 84 (with the exception of R. sanguineus on Day 63). Ticks were counted at 24 h post-infestation.The dogs from both treated groups had statistically significantly (p < 0.05) less R. sanguineus and D. reticulatus ticks compared to the untreated dogs on all assessment days. Percent efficacy against R. sanguineus ranged from 86.4% to 99.5% at 24 h post-infestation for NexGard® and from 65.7% to 100% for Bravecto™. Statistically significantly (p < 0.05) less R. sanguineus ticks were recorded for NexGard® treated dogs compared to Bravecto™ treated dogs on Day 78. Percent efficacy against D. reticulatus ranged from 85.2% to 99.6% at 24 h post-infestation for NexGard® and from 63.4% to 99.1% for Bravecto™. Statistically significantly (p < 0.05) less D. reticulatus ticks were recorded for NexGard® treated dogs compared to Bravecto™ treated dogs on Days 71, 78 and 85.