A comparative evaluation of the speed of kill and duration of efficacy against weekly infestations with fleas on cats treated with fipronil-(S)-methoprene or metaflumizone.

Spot-on formulations of metaflumizone and a combination of fipronil-(S)-methoprene were evaluated in adult cats to determine the duration of 24- and 48-hour efficacy and short-term speed of kill against adult cat fleas, Ctenocephalides felis felis. Speed of kill efficacies (at 12, 18, 24, and 48 hours) were assessed against existing (day -1) infestations and against infestations at day 7, and efficacy was assessed 24 and 48 hours after weekly flea infestations through day 42. Cats treated with fipronil-(S)-methoprene had significantly (P<.01) fewer fleas than those treated with metaflumizone at 12 and 18 hours after treatment (day 0) and on the day 7 infestations. Fipronil-(S)-methoprene-treated cats also had significantly (P<.05) fewer fleas than metaflumizone-treated cats for all 24-hour counts from initial treatment on day 0 through infestation day 42 and for the 48-hour counts on day 28 through day 42.