title: Efficacy of a new combination of fipronil and permethrin against Ctenocephalides felis flea infestation in dogs.
abstract: BACKGROUND
  Five studies were conducted to evaluate the effect of a new combination of fipronil and permethrin on cat fleas, Ctenocephalides felis, when applied to dogs, including dogs that underwent water exposure or shampooing.
  
  
  METHODS
  In each study, 16 dogs were allocated to two groups. Each dog was infested with 100 unfed adult fleas on Days -1, 7, 14, 21 and 28. Eight dogs were treated with a new topical spot-on formulation containing 6.76% w/v fipronil + 50.48% w/v permethrinon Day 0; and eight dogs served as untreated controls. Twenty-four or 48 h after treatment or subsequent infestation, each dog was combed to remove and count live fleas. In addition, the dogs were subjected to different levels of water or shampoo exposure. In study 1, dogs were not subjected to any water exposure or shampooing; in study 2, dogs were water immersed twice during the month on Days 10 and 24; in study 3, dogs were water immersed three times on Days 10, 17 and 24; and in studies 4 and 5, dogs were shampooed once on Day 17.
  
  
  RESULTS
  All groups of dogs administered a single topical treatment with a combination of fipronil and permethrin had significantly (p < 0.005) lower flea counts than untreated controls 24 h and 48 h post-treatment or post-infestation, regardless of whether they underwent water exposure/shampooing or not. The reductions in C. felis counts were between 98.4% and 100% at all time points in all studies.
  
  
  CONCLUSIONS
  The new topical spot-on formulation of fipronil and permethrin maintains a high level of protection of dogs against C. felis flea infestations even when the dogs are exposed to environmental factors that are believed to adversely affect efficacy, such as water exposure or shampooing.
authors: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. becky.fankhauser@merial.com.
authors: Becky
authors: B
authors: Fankhauser
authors: Merial S.A.S, 29 avenue Tony Garnier, Lyon, 69007, France. pascal.dumont@merial.com.
authors: Pascal
authors: P
authors: Dumont
authors: Merial S.A.S, 29 avenue Tony Garnier, Lyon, 69007, France. lenaig.halos@merial.com.
authors: Lénaïg
authors: L
authors: Halos
authors: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. james.hunter@merial.com.
authors: James S
authors: JS
authors: Hunter
authors: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. bruce.kunkle@merial.com.
authors: Bruce
authors: B
authors: Kunkle
authors: BerTek, Inc, 104 Wilson Bottoms Rd, Greenbrier, AR, 72058, USA. wreverett@bertekconsults.com.
authors: William R
authors: WR
authors: Everett
authors: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. ted.chester@merial.com.
authors: Theodore S
authors: TS
authors: Chester
authors: ClinVet International (Pty) Ltd, PO Box 11186, Bloemfontein , 9321 Universitas, South Africa. josephus.fourie@clinvet.com.
authors: Josephus J
authors: JJ
authors: Fourie
authors: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. mark.soll@merial.com.
authors: Mark D
authors: MD
authors: Soll
mesh_terms: D000287:Administration, Topical; D000818:Animals; D058251:Ctenocephalides / Q000187:drug effects* / Q000502:physiology; D004283:Dog Diseases / Q000188:drug therapy* / Q000469:parasitology; D004285:Dogs; D004341:Drug Evaluation; D004359:Drug Therapy, Combination / Q000662:veterinary; D005260:Female; D058267:Flea Infestations / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D007306:Insecticides / Q000008:administration & dosage*; D008297:Male; D026023:Permethrin / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage*
chemical_list: D007306:Insecticides; D011720:Pyrazoles; D026023:Permethrin; C082360:fipronil
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