Efficacy of fluralaner against Otodectes cynotis infestations in dogs and cats

Janina Taenzler, Christa de Vos, Rainer K. A. Roepke, Régis Frénais, Anja R. Heckeroth

The efficacy of fluralaner for the treatment of Otodectes cynotis infestations in dogs and cats was evaluated after oral (dogs) or topical administration (dogs and cats). Twenty-four dogs and sixteen cats were experimentally infested with O. cynotis and randomly allocated to equal sized groups (n = 8/group). Dog groups were treated once, either orally with fluralaner at a minimum dose of 25 mg/kg body weight, topically with fluralaner at a dose of 25 mg/kg body weight or topically with saline solution (control). Cat groups were treated once, either topically with fluralaner at a dose of 40 mg/kg body weight or topically with saline solution. Ears of all animals were examined otoscopically for live visible mites and the amount of debris and cerumen before, and 14 and 28 days after treatment. Twenty-eight days after treatment, animals were sedated and both ears were flushed to obtain the total number of live mites per animal. The efficacy was calculated, based on the results of the ear flushing, by comparing mean live mite counts in the fluralaner treated groups versus the saline solution treated group. A single topical treatment of cats with fluralaner reduced the mean mite counts by 100% (P < 0.001) at 28 days after treatment. Similarly, a single oral or topical treatment of dogs with fluralaner reduced the mean mite counts by 99.8% (P < 0.001) at 28 days after treatment. Cats treated topically with fluralaner had no mites visible during otoscopic examination at either 14 or 28 days after treatment. All dogs treated orally or topically with fluralaner had no mites visible during otoscopic examination at 28 days after treatment. At 14 days after treatment, only 1-2 mites were visible in three dogs (oral treatment: 2 dogs, topical treatment: 1 dog). All fluralaner-treated animals showed improvement in the amount of cerumen exudation compared with observations performed before treatment. No treatment related adverse events were observed in any dogs or cats enrolled in these studies. In this study, fluralaner administered topically to cats and orally or topically to dogs was highly effective against Otodectes cynotis mite infestations.