title: Efficacy of fipronil (9.8% w/w) + (S)-methoprene (8.8% w/w) and imidacloprid (8.8% w/w) + permethrin (44% w/w) against Dermacentor variabilis (American dog tick) on dogs.
abstract: This study evaluated overall efficacy, percentage of dogs free of live ticks, retention of ticks, and efficacy against retained ticks of fipronil (9.8% w/w) + (S)-methoprene (8.8% w/w) and imidacloprid (8.8% w/w) + permethrin (44% w/w) spot-on topical solutions against Dermacentor variabilis-infested dogs. Tick control was significantly greater (P < .05) on dogs treated with fipronil + (S)-methoprene than on control dogs for the entire 30-day study period. Conversely, the combination product of imidacloprid + permethrin demonstrated activity significantly (P < .05) different from that seen on control dogs only up to day 23. Significantly (P < .05) more dogs treated with fipronil + (S)-methoprene were free of live ticks compared with controls on days 3, 9, and 16. There was never a significant difference (P > .05) between control and imidacloprid + permethrin-treated dogs in numbers of dogs free of live ticks. After the initial 10-minute tick exposure, lower numbers of ticks were retained on the imidacloprid + permethrin-treated dogs than on the fipronil + (S)-methoprene-treated dogs. However, when evaluating the effectiveness of the acaricides on "retained ticks," it appears that while some of the ticks were rapidly knocked down on the imidacloprid + permethrin-treated dogs, efficacy against ticks still retained at 10 minutes was never greater than 50%.
authors.affiliation: Kansas State University.
authors.forename: M W
authors.initials: MW
authors.lastname: Dryden
authors.forename: P A
authors.initials: PA
authors.lastname: Payne
authors.forename: A
authors.initials: A
authors.lastname: McBride
authors.forename: S
authors.initials: S
authors.lastname: Mailen
authors.forename: V
authors.initials: V
authors.lastname: Smith
authors.forename: D
authors.initials: D
authors.lastname: Carithers
mesh_terms: D000818:Animals; D003870:Dermacentor / Q000187:drug effects*; D004283:Dog Diseases / Q000188:drug therapy / Q000469:parasitology*; D004285:Dogs; D004338:Drug Combinations; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage / Q000627:therapeutic use; D007306:Insecticides / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008726:Methoprene / Q000008:administration & dosage / Q000627:therapeutic use; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000008:administration & dosage / Q000627:therapeutic use; D026023:Permethrin / Q000008:administration & dosage / Q000627:therapeutic use; D011720:Pyrazoles / Q000008:administration & dosage / Q000627:therapeutic use; D013984:Tick Infestations / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D004338:Drug Combinations; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011720:Pyrazoles; C082359:imidacloprid; D026023:Permethrin; D008726:Methoprene; C082360:fipronil