Comparative speed of kill of oral treatments with Simparica™ (sarolaner) and Bravecto®(fluralaner) against induced infestations of Rhipicephalus sanguineus on dogs.

Abstract

BackgroundRhipicephalus sanguineus is the most widely distributed tick species infesting dogs worldwide, which may cause discomfort to the host and transmit diseases. Acaricides with a rapid and sustained speed of kill are thus important to prevent infestation and to reduce the risk of disease transmission. In this study, the speed of kill of a monthly administered SimparicaTM(sarolaner) treatment against induced infestations with R. sanguineus on dogs was evaluated and compared with a single dose of Bravecto®(fluralaner) for 95 days after the initial treatment.MethodsTwenty four dogs were randomly allocated to treatment and were treated with either placebo or sarolaner (at 2 to 4 mg/kg) on Days 0, 30 and 60 or with fluralaner (at 25 to 56 mg/kg) once on Day 0. Tick counts were performed in situ 8 and 12 h and with removal of the ticks 24 h after treatment and subsequent re-infestations on Days 14, 28, 44, 56, 74, 90 and 95. Acaricidal efficacy was determined at each time point relative to the placebo group.ResultsBoth products significantly reduced live ticks within 8 h after treatment against an existing infestation with R. sanguineus, and killed all ticks on all dogs within 24 h. After re-infestation, sarolaner provided ≥98.5 % reduction within 24 h on all days except Days 74 and 95 (P < 0.0001), compared to fluralaner which provided ≥95.5 % reduction until Day 44. Geometric mean live tick counts for sarolaner were significantly lower (P ≤ 0.0415) at 24 h than those for fluralaner on all days, except on Days 0, 14 and 28 (P ≥ 0.0678). There were no treatment-related adverse reactions observed during the study.ConclusionsWhen dosed at monthly intervals for 3 consecutive months, SimparicaTM has a faster and more consistent speed of kill against R. sanguineus than a single oral dose of Bravecto® for which efficacy decreased after Day 44.