Curative and preventive efficacy of orally administered afoxolaner against Ctenocephalides canis infestation in dogs

Abstract

The efficacy of orally administered afoxolaner against adult dog fleas, Ctenocephalides canis, was evaluated in a controlled, blinded study. A total of 32 dogs were infested with 100 adult unfed fleas approximately 24h prior to treatment and then at weekly intervals for 5 weeks after treatment. Live fleas were counted upon removal at 12h (for 16 dogs) and 24h (for the remaining 16 dogs) after treatment (for counts performed the first week) or after infestation (for counts performed on subsequent weeks). In addition, flea eggs were collected from each pen and counted for the dogs with flea removal at 24h. Dosing of individual dogs was achieved using a combination of the chewable tablets to be as close as possible to the minimum effective dose of 2.5mg/kg. The percent efficacy of the afoxolaner treatment was ≥ 99.0% for all 24-h flea counts. For flea counts performed 12h after treatment or infestations, the percent efficacy was ≥ 94.1% up to Day 21. After Day 1, no flea eggs were recovered from the afoxolaner treated group, providing 100% reduction in numbers of flea eggs recovered versus untreated control group. This study confirmed that a single oral treatment with afoxolaner provided excellent efficacy against infestations by C. canis within 12-24h after treatment, prevented re-infestations, and completely prevented egg production from new flea infestations for up to 5 weeks.

Systemic insecticide treatment of the canine reservoir of Trypanosoma cruzi induces high levels of lethality in Triatoma infestans, a principal vector of Chagas disease

“…Similarly, a single dose of NexGard®, reduced populations of C. felis by 100% within 24 h and blocked egg production by >99% over 36 days [22, 23]; additional re-treatment at days 28–30, achieved total flea control by 60 days [24]. Other studies of single doses of NexGard® report complete elimination of pre-existing Dermacentor reticulatus, D. variabilis and Ixodes ricinus infestations and sustained efficacy of >96% one month later [25, 26] and significant reductions in R. sanguineus and Haemaphysalis longicornis by >96% after 35 days [27] and 92% after 30 days [28], respectively; maximum plasma levels are observed at 2–6 h and mean half-life is 15.5 days [17]. A direct comparison of immediate efficacy of Bravecto® and NexGard® against R. sanguineus demonstrated that onset of activity was 4 h and 8 h, respectively, and 100% mortality was achieved within 12 h and 48 h, respectively [21].…”

Safety evaluation of orally administered afoxolaner and milbemycin oxime in eight‐week‐old dogs

“…Advances in research for ectoparasite control have brought a new oral therapeutic drug forward for clinical usage. NexGard ® (Merial Inc., Duluth, GA, USA; a beef‐flavored chewable for dogs) contains afoxolaner (a compound from a new structurally unique isoxazoline class), which acts as a novel and specific blocker of insect ligand‐gated chloride ion channels (Shoop et al ., ) and is thus effective against both fleas and ticks (Dumont et al ., ,b Hunter et al ., ; Kondo et al ., Kunkle et al ., ,b Mitchell et al ., ,b). Combining afoxolaner with milbemycin oxime in a beef‐flavored chewable allows owners to administer one product per month instead of several because milbemycin oxime extends the spectrum of activity to the treatment of intestinal nematodes and prevention of heartworm disease ( Dirofilaria immitis ).…”

The intravenous and oral pharmacokinetics of afoxolaner and milbemycin oxime when used as a combination chewable parasiticide for dogs

“…Afoxolaner is a highly effective ectoparasiticide used against flea and tick infestations in dogs (Dumont et al ., ,b; Hunter et al ., ; Kondo et al ., ; Kunkle et al ., ,b; Mitchell et al ., ,b). The high potency against fleas and ticks is a hallmark of isoxazoline parasiticides (Ozoe et al ., ; Woods et al ., ).…”