EFFICACY OF IMIDACLOPRID FOR REMOVAL AND CONTROL OF FLEAS (CTENOCEPHALIDES-FELIS) ON DOGS

Objective-To evaluate efficacy of a 9.1% (w/w) imidacloprid solution, applied topically, to remove fleas from dogs and the duration of resid ual flea control when dogs were exposed to continuing flea infestation . Animals-32 adult mixed-breed dogs. Procedure-Dogs were allocated to 4 groups of 8 dogs each; dogs of 3 groups received a single dose of im idacloprid, and those of the fourth group received excipient. Each dog was infested with 100 adult fleas on study days -3, -1, 6, 13, 20, 27 , and 33. Treatments were applied on day 0. Each dog was examined for live fleas on days -2, 1, 7, 14, 21, 28, and 34. Posttreatment efficac y was determined by comparing the mean number of live fleas remaining on the treated dogs with the mean number of live fleas remaining on th e control dogs. Results-All 3 imidacloprid dosages provided flea contr ol greater than or equal to 96.9% one day after treatment. Maximal eff icacy of all 3 dosages (99.1 to 100%) was observed at 7 days after tre atment. Flea control with 3.75 mg of imidacloprid/kg of body weight ra nged from 94.4 to 96.9% for days 14 to 28 and decreased to 91.6% by 34 days after treatment. Flea control with 7.5 and 10.0 mg of imidaclopr id/kg was 97.8 to 100% through day 28. At day 34, dosages of 7.5 and 1 0.0 mg of imidacloprid/kg were 97.6 and 96.9% efficacious, respectivel y.Conclusion-7.5 or 10.0 mg of imidacloprid/kg are equivalent and supe rior to 3.75 mg/kg for flea control over the course of a 34 day posttr eatment period. Clinical Relevance-Monthly imidacloprid application of 75 to 10 mg/kg will rapidly kill existing and reinfesting flea infest ations on dogs and break the flea life cycle by killing adult fleas be fore egg production begins.