title: Acaricidal efficacy of a new combination of fipronil and permethrin against Ixodes ricinus and Rhipicephalus sanguineus ticks.
abstract: BACKGROUND
  Two blinded, controlled laboratory studies were conducted to assess the acaricidal efficacy of a new combination of fipronil and permethrin (Frontline Tri-Act/Frontect) against two tick species. Study A evaluated the efficacy of the product against both Ixodes ricinus and Rhipicephalus sanguineus and Study B evaluated the efficacy against R. sanguineus only.
  
  
  METHODS
  16 (Study A) and 12 (Study B) healthy adult dogs were allocated to two groups in each study. Dogs in Group 1 served as untreated controls. Dogs in Group 2 were treated with a new topical spot-on formulation containing 6.76% (w/v) fipronil + 50.48% (w/v) permethrin once on Day 0. Each dog of study A was infested with 50 unfed adult ticks of each species and each dog of study B was infested with 50 unfed adult Rhipicephalus sanguineus prior to treatment (Day -2 in Study A, Day -1 in Study B) and post treatment on Days 7, 14, 21 and 28. The ticks were removed and counted 48 h after treatment (Day 2) or subsequent infestations (Days 9, 16, 23 and 30). Acaricidal efficacy was defined as the percent reduction in the number of live ticks in the treated group compared to the untreated control group.
  
  
  RESULTS
  The percent efficacy in the treated group for R. sanguineus was 100%, 100%, 100%, 100% and 96.7% in Study A, and 94.4%, 100%, 100%, 98.7% and 98.0% in Study B, for counts performed on Days 2, 9, 16, 23 and 30, respectively. For I. ricinus, in Study A, the percent efficacy of the treatment was 100%, 100%, 100%, 100% and 99.2% for counts performed on Days 2, 9, 16, 23 and 30, respectively. There was a significant difference of the geometric mean numbers of live ticks between the treated and control groups at each time point in each study (p = 0.005 for every day in Study A, and p < 0.005 for every day in Study B).
  
  
  CONCLUSIONS
  A single topical administration of a combination of fipronil and permethrin provides excellent acaricidal efficacy against both I. ricinus and R. sanguineus for at least 4 weeks.
authors.affiliation: Merial S.A.S., 29 Av. Tony Garnier, 69007, Lyon, France. pascal.dumont@merial.com.
authors.forename: Pascal
authors.initials: P
authors.lastname: Dumont
authors.affiliation: Merial Limited, 3239 Satellite Blvd., Duluth, GA, 30096, USA. ted.chester@merial.com.
authors.forename: Theodore S
authors.initials: TS
authors.lastname: Chester
authors.affiliation: Charles River Laboratories Preclinical Services Ireland Ltd., Carrentrila, Ballina, Co. Mayo, Ireland. boyd.gale@crl.com.
authors.forename: Boyd
authors.initials: B
authors.lastname: Gale
authors.affiliation: Merial Limited, 3239 Satellite Blvd., Duluth, GA, 30096, USA. mark.soll@merial.com.
authors.forename: Mark
authors.initials: M
authors.lastname: Soll
authors.affiliation: ClinVet International (Pty) Ltd, PO Box 11186, 9321 Universitas, Bloemfontein, South Africa. josephus.fourie@clinvet.com.
authors.forename: Josephus J
authors.initials: JJ
authors.lastname: Fourie
authors.affiliation: Merial S.A.S., 29 Av. Tony Garnier, 69007, Lyon, France. frederic.beugnet@merial.com.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Beugnet
mesh_terms: D056810:Acaricides / Q000008:administration & dosage*; D000287:Administration, Topical; D000818:Animals; D004283:Dog Diseases / Q000188:drug therapy* / Q000469:parasitology; D004285:Dogs; D004341:Drug Evaluation / Q000662:veterinary; D004359:Drug Therapy, Combination / Q000662:veterinary; D005260:Female; D018884:Ixodes / Q000187:drug effects* / Q000502:physiology; D008297:Male; D026023:Permethrin / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage*; D048508:Rhipicephalus sanguineus / Q000187:drug effects* / Q000502:physiology; D013983:Tick Control / Q000379:methods; D013984:Tick Infestations / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*
chemical_list: D056810:Acaricides; D011720:Pyrazoles; D026023:Permethrin; C082360:fipronil