title: Knock-down and speed of kill of a combination of fipronil and permethrin for the prevention of Ctenocephalides felis flea infestation in dogs.
abstract: BACKGROUND
  A topical combination of fipronil + permethrin (Frontline Tri-Act/Frontect, Merial) has recently been developed to control fleas, ticks, mosquitoes, sandflies and stable flies on dogs. Two studies were conducted to assess its speed of kill and knock-down effect on Ctenocephalides felis fleas. The combination was compared to either fipronil alone or to a combination of permethrin, dinotefuran, and pyriproxyfen,
  
  
  METHODS
  In each study, 18 dogs were randomly allocated to one of three groups: (Group 1: untreated dog; Group 2: treated once on D0 with the combination of fipronil and permethrin; Group 3: treated once on D0 either with fipronil alone (study 1) or with a combination of permethrin, dinetofuran and pyriproxyfen (study 2)). Each dog was infested with 100 unfed adult C. felis fleas on Days 2 (study 2), 7, 14, 21 and 28. Fleas were collected from dogs at 1 h and 12 h post- infestations (PI) (study 1) or at 2 h and 6 h PI (study 2) to assess efficacy and from collection pans underneath cages 1 h (study 1) or 5 min (study 2) PI to assess knock-down effect.
  
  
  RESULTS
  All treated dogs had significantly (p ≤ 0.01) lower flea counts than untreated dogs at every time point in both studies. For a whole month, a significant knock-down effect against infesting fleas is obtained in five minutes PI with the combination of permethrin and fipronil. Complete efficacy (>95%) was achieved in 1 h (study 1) or 2 h (study 2) PI for 14 days and by 6 h PI for all challenges conducted throughout the month. Efficacy remains >85% at 2 h PI for the whole month. A significantly higher efficacy of the fipronil + permethrin combination compared to other treatments was demonstrated at the earliest time points for the month (1 h knock-down effect and insecticidal efficacy compared to fipronil alone; 5 min knock-down effect compared to the combination of permethrin + dinetofuran + pyriproxyfen).
  
  
  CONCLUSIONS
  The rapid flea knock-down effect and speed of kill demonstrated by the spot on combination of fipronil + permethrin provide a reliable strategy against flea infestations in dogs.
authors.affiliation: Merial S.A.S., 29 Av Tony Garnier, 69007, Lyon, France. Lenaig.halos@merial.com.
authors.forename: Lénaïg
authors.initials: L
authors.lastname: Halos
authors.affiliation: ClinVet International (Pty) Ltd, P.O. Box 11186, Universitas, Bloemfontein, 9321, Republic of South Africa. josephus.fourie@clinvet.com.
authors.forename: Josephus J
authors.initials: JJ
authors.lastname: Fourie
authors.affiliation: Merial Limited, 3239 Satellite Blvd, Duluth, GA, 30096, USA. becky.fankhauser@merial.com.
authors.forename: Becky
authors.initials: B
authors.lastname: Fankhauser
authors.affiliation: Merial S.A.S., 29 Av Tony Garnier, 69007, Lyon, France. Frederic.beugnet@merial.com.
authors.forename: Frederic
authors.initials: F
authors.lastname: Beugnet
mesh_terms: D000818:Animals; D018890:Chemoprevention / Q000379:methods*; D058251:Ctenocephalides / Q000187:drug effects* / Q000502:physiology; D004283:Dog Diseases / Q000469:parasitology / Q000517:prevention & control*; D004285:Dogs; D004359:Drug Therapy, Combination / Q000379:methods; D058267:Flea Infestations / Q000469:parasitology / Q000517:prevention & control*; D007306:Insecticides / Q000008:administration & dosage*; D026023:Permethrin / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage*; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D007306:Insecticides; D011720:Pyrazoles; D026023:Permethrin; C082360:fipronil
references.citation: J Med Entomol. 2000 Jul;37(4):634-6
references.pmid: 10916307
references.citation: Trends Parasitol. 2012 Jul;28(7):267-79
references.pmid: 22627116
references.citation: Vet Parasitol. 2013 May 1;194(1):84-97
references.pmid: 23741753
references.citation: Parasit Vectors. 2014;7:353
references.pmid: 25084969
references.citation: Parasit Vectors. 2015;8:62
references.pmid: 25630582
references.citation: Parasit Vectors. 2015;8:52
references.pmid: 25622656
references.citation: Parasitol Res. 2015 Jul;114(7):2649-57
references.pmid: 25869961
references.citation: Parasit Vectors. 2015;8:602
references.pmid: 26586365
references.citation: Parasite. 2016;23:2
references.pmid: 26795064
references.citation: J Parasitol. 2001 Feb;87(1):214-5
references.pmid: 11227894
references.citation: Vet Clin North Am Small Anim Pract. 1988 Sep;18(5):1023-42
references.pmid: 3055642
references.citation: Trends Parasitol. 2005 May;21(5):232-6
references.pmid: 15837612
references.citation: Vet Parasitol. 2009 Aug 26;163(4):298-305
references.pmid: 19403239
references.citation: Trends Parasitol. 2010 Apr;26(4):197-204
references.pmid: 20185369
references.citation: Vet Dermatol. 2012 Dec;23(6):487-e93
references.pmid: 23013416