title: Afoxolaner against fleas: immediate efficacy and resultant mortality after short exposure on dogs.
abstract: The speed of efficacy of afoxolaner (NexGard) against Ctenocephalides felis fleas was evaluated in two studies. Study A assessed the efficacy against existing fleas whereas study B assessed the efficacy against new infesting fleas. In study A, 12 dogs were allocated to the untreated group and 20 dogs to the treated group. All dogs were infested by 100 fleas each at Day -1, treated at Day 0 and flea combed at 2 h or at 6 h post treatment. In study B, 6 dogs were allocated to the untreated group and 10 to the treated group. They were infested with 100 fleas each on Days 2, 7, 14, 21 and 28. Fleas were removed and counted at 6 h post-infestation. Immediate and persistent efficacies were evaluated by counting fleas on the dogs. To evaluate induced mortality after exposure on dogs, fleas collected alive were placed in an insectarium for 24 h and assessed for viability. The immediate efficacy on dogs was significant at 6 h with 100%. The induced death of the fleas collected live from dogs 2 h after exposure was 99.7%. Concerning new infesting fleas, the observed efficacy at 6 h and the induced mortality were significantly different (p < 0.05) from the control at all time-points. At 6 h, the prophylactic efficacy was > 97% at Day 2 and Day 8 and > 90% at Day 14. The induced mortality after 6 h of exposure on dogs varied between 73.3% and 100% for the whole study.
authors.affiliation: Merial S.A.S., 29 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Beugnet
authors.affiliation: ClinVet International, Universitas, 9301 Bloemfontein, Free State, South Africa.
authors.forename: Christa
authors.initials: C
authors.lastname: deVos
authors.affiliation: ClinVet International, Universitas, 9301 Bloemfontein, Free State, South Africa.
authors.forename: Julian
authors.initials: J
authors.lastname: Liebenberg
authors.affiliation: Merial S.A.S., 29 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Lénaïg
authors.initials: L
authors.lastname: Halos
authors.affiliation: ClinVet International, Universitas, 9301 Bloemfontein, Free State, South Africa.
authors.forename: Josephus
authors.initials: J
authors.lastname: Fourie
mesh_terms: D000818:Animals; D058251:Ctenocephalides / Q000187:drug effects; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D058267:Flea Infestations / Q000188:drug therapy / Q000662:veterinary*; D018756:GABA Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D019476:Insect Proteins / Q000037:antagonists & inhibitors; D007306:Insecticides / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D007555:Isoxazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D009281:Naphthalenes / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D019476:Insect Proteins; D007306:Insecticides; D007555:Isoxazoles; D009281:Naphthalenes; C000589002:afoxolaner