The effect of water and shampooing on the efficacy of fluralaner spot-on solution against Ixodes ricinus and Ctenocephalides felis infestations in dogs

BACKGROUND: Fluralaner spot-on solution provides immediate and persistent efficacy against tick and flea infestations in dogs and cats for 12-weeks following topical administration. The active ingredient fluralaner is distributed systemically following transdermal absorption. Therefore, this study tested the hypothesis whether water-immersion or shampooing of dogs following administration of fluralaner spot-on solution has an impact on subsequent tick and flea efficacy. METHODS: Thirty-two Beagle dogs were allocated to four study groups of 8 dogs each. On day 0, dogs in the 2 treatment groups received topical administration of fluralaner (Bravecto™ spot-on solution) according to label instructions. Dogs in the 2 corresponding control groups remained untreated. On days 3, 21, 49, and 77 dogs in one treatment group and control group were water-immersed for 2–5 min, while dogs in the other treatment group and control group were shampooed 6–8 min with a commercial foaming micro-emulsion, unscented product. On days 4, 28, 56, and 84 all dogs were co-infested with 50 ± 2 female and 10 ± 2 male Ixodes ricinus and 100 ± 4 Ctenocephalides felis, with tick and flea removal and counts 48 ± 2 h post-infestation. Efficacy against ticks and fleas was calculated for each assessment time point. RESULTS: No treatment-related adverse event was observed in any of the 16 dogs treated with fluralaner spot-on solution during the study. Efficacy against ticks at each assessment time point was between 99.7 and 100 % in the water-immersed group and between 99.2 and 100 % in the shampooed group. Efficacy against fleas was 100 % at each assessment time point as well in the water-immersed as the shampooed group. Tick and flea reduction in both treatment groups was significant at all assessment time points (p < 0.0001). CONCLUSIONS: Neither water-immersion nor shampooing after single topical administration of fluralaner spot-on solution had an impact on the excellent tick and flea efficacy over the 12-week recommended re-treatment interval.