Efficacy of imidacloprid + moxidectin and selamectin topical solutions against the KS1 Ctenocephalides felis flea strain infesting cats

Background: two studies were conducted to evaluate and compare the efficacy of imidacloprid + moxidectin and selamectin topical solutions against the ks1 flea strain infesting cats. in both studies the treatment groups were comprised of non-treated controls,6% w/v selamectin (revolution®; pfizer animal health) topical solution and 10% w/v imidacloprid + 1% w/v moxidectin (advantage multi for cats,bayer animal health) topical solution. all cats were infested with 100 fleas on days -2,7,14,21,and 28. the difference in the studies was that in study #1 efficacy evaluations were conducted at 24 and 48 hours post-treatment or post-infestation,and in study #2 evaluations were conducted at 12 and 24 hours. results: in study #1 imidacloprid + moxidectin and the selamectin formulation provided 99.8% and 99.0% efficacy at 24 hours post-treatment. on day 28,the 24 hour efficacy of the selamectin formulation dropped to 87.1%,whereas the imidacloprid + moxidectin formulation provided 98.9% efficacy. at the 48 hour assessments following the 28 day infestations,efficacy of the imidacloprid + moxidectin and selamectin formulations was 96.8% and 98.3% respectively. in study # 2 the efficacy of the imidacloprid + moxidectin and selamectin formulations 12 hours after treatment was 100% and 69.4%,respectively. on day 28,efficacy of the imidacloprid + moxidectin and selamectin formulations 12 hours after infestation was 90.2% and 57.3%,respectively. in study #2 both formulations provided high levels of efficacy at the 24 hour post-infestation assessments,with selamectin and imidacloprid + moxidectin providing 95.3% and 97.5% efficacy,following infestations on day 28. conclusions: at the 24 and 48 hour residual efficacy assessments,the imidacloprid + moxidectin and selamectin formulations were similarly highly efficacious. however,the imidacloprid + moxidectin formulation provided a significantly higher rate of flea kill against the ks1 flea strain infesting cats at every 12 hour post-infestation residual efficacy assessment. both formulations should provide excellent flea control for an entire month on cats. © 2011 dryden et al; licensee biomed central ltd.