Comparative speed of kill, repellent (anti-feeding) and acaricidal efficacy of an Imidacloprid/flumethrin collar (Seresto®) and a fipronil/(S)-methoprene/eprinomectin/praziquantel spot-on (Broadline®) against Ixodes ricinus (Linné, 1758) on cats

Abstract

Speed of kill, repellent (anti-feeding) and acaricidal efficacy of an imidacloprid 10% (w/w) /flumethrin 4.5% (w/w) collar (Seresto®, Bayer) and a spot-on formulation of fipronil 8.3% (w/v) /(S)-methoprene 10% (w/v) /eprinomectin 0.4% (w/v) /praziquantel 8.3% (w/v) (Broadline®, Merial) against artificially-induced infestations with Ixodes ricinus on cats, were assessed in a parallel group design, randomized, controlled study. Twenty-four cats were included and randomly allocated to treatment groups or non-treated controls. Starting on Day (D) 7 after treatment until D28, cats were each infested with 50 I. ricinus at weekly intervals. Ticks were counted in situ on the cats at 6, 12 and 24 h and upon removal 48 h after each infestation. Based on arithmetic means, Seresto® proved to be 100% effective against adult I. ricinus at all assessment times (6, 12, 24 and 48 h after infestation) throughout the month-long study. Broadline® was 0% to 16.7% effective at 6 h, 26.8% to 50.0% effective at 12 h, while at 24 h after infestation efficacy peaked at 81.5% on D15 declining to 31.5% on D29. Based on the 48 h tick counts, the efficacy of Broadline® peaked at 100% on D16 after treatment and decreased to 83.2% by D30. The Seresto® collar provided significantly faster speed of kill and better persistent acaricidal effectiveness against Ixodes ricinus on cats compared to Broadline® spot-on. The additional repellent (antifeeding) effect of Seresto® prevents parasites from taking a blood meal and thereby reduces the risk of vectorborne disease pathogen transmission.