Curative and preventive efficacy of orally administered afoxolaner against Ctenocephalides canis infestation in dogs

The efficacy of orally administered afoxolaner against adult dog fleas, Ctenocephalides canis, was evaluated in a controlled, blinded study. A total of 32 dogs were infested with 100 adult unfed fleas approximately 24h prior to treatment and then at weekly intervals for 5 weeks after treatment. Live fleas were counted upon removal at 12h (for 16 dogs) and 24h (for the remaining 16 dogs) after treatment (for counts performed the first week) or after infestation (for counts performed on subsequent weeks). In addition, flea eggs were collected from each pen and counted for the dogs with flea removal at 24h. Dosing of individual dogs was achieved using a combination of the chewable tablets to be as close as possible to the minimum effective dose of 2.5mg/kg. The percent efficacy of the afoxolaner treatment was ≥99.0% for all 24-h flea counts. For flea counts performed 12h after treatment or infestations, the percent efficacy was ≥94.1% up to Day 21. After Day 1, no flea eggs were recovered from the afoxolaner treated group, providing 100% reduction in numbers of flea eggs recovered versus untreated control group. This study confirmed that a single oral treatment with afoxolaner provided excellent efficacy against infestations by C. canis within 12–24h after treatment, prevented re-infestations, and completely prevented egg production from new flea infestations for up to 5 weeks.