Fluralaner, a novel isoxazoline, prevents flea (Ctenocephalides felis) reproduction in vitro and in a simulated home environment

Abstract

BackgroundFluralaner, a novel isoxazoline, has both acaricidal and insecticidal activity through potent blockage of GABA- and L-glutamate-gated chloride channels. This study investigated the in vitro and in vivo effects of fluralaner exposure on flea (Ctenocephalides felis) reproduction.MethodsBlood spiked with sub-insecticidal fluralaner concentrations (between 0.09 and 50.0 ng/mL) was fed to fleas for 10 days using a membrane system. Cessation of reproduction in exposed fleas was assessed using flea survival, egg hatchability, and control of oviposition, pupae, and flea emergence. Fluralaner efficacy for in vivo Ctenocephalides (C.) felis control on dogs was assessed using a simulated flea-infested home environment. During a pre-treatment period, dogs were infested twice on days -28 and -21 with 100 adult unfed fleas to establish a thriving population by day 0 of the study. On day 0, one group of dogs was treated with fluralaner (Bravecto™; n = 10), while another group served as negative control (n = 10). Following treatment, dogs were infested three times with 50 fleas on days 22, 50 and 78 to simulate new infestations. Live flea counts were conducted weekly on all dogs for 12 weeks starting 1 day before treatment.ResultsFluralaner potently inhibited flea reproduction capacity in vitro. Oviposition ceased completely at concentrations as low as 25.0 ng/mL. While no ovicidal effect was observed, fluralaner exerted a larvicidal effect at exceptionally low concentrations (6.25 ng/mL). In the simulated flea-infested home environment, flea-control efficacy on fluralaner-treated dogs was >99% at every time point measured for 12 weeks. No adverse events were observed in fluralaner-treated dogs.ConclusionsFluralaner completely controls egg laying, larval development and flea reproduction even at sub-insecticidal concentrations. Oral treatment of dogs with fluralaner is highly effective for eliminating fleas in a simulated flea-infested home environment.

Results from a U.S. Dog Owner Survey on the Treatment Satisfaction and Preference for Fluralaner against Flea and Tick Infestations

“…There is a wide assortment of approved oral and topical canine F/T medications with various modes of action and in various combinations, including some with insect growth regulator activity and some with canine heartworm (HW) indications. Fluralaner is a recently approved active ingredient in the isoxazoline class available in oral chewable formulation (Fluralaner, Merck Animal Health, Madison, NJ, USA) for dogs and a topical formulation for dogs and cats [4,5]. The fluralaner re-treatment interval is three times longer than the re-treatment interval for other flea/tick products that are dosed every 4 weeks.…”

Assessment of the efficacy of a topical combination of fipronil-permethrin (Frontline Tri-Act®/Frontect®) against egg laying and adult emergence of the cat flea (Ctenocephalides felis) in dogs

“…The sustained speed of kill of an insecticidal product is essential for the control of environmental contamination by immature flea stages. The ability to prevent egg production has recently been demonstrated in experimental studies with ectoparasiticides containing isoxazolines (afoxolaner, sarolaner or fluralaner) having a sustained speed of kill of less than 24 h for 1–3 months [3, 19, 20]. It has also been demonstrated in the field in studies using flea traps to assess environmental control [7, 8].…”

“…Anti-flea products containing insect growth regulators (IGRs) have proven to be effective for the control of infested environments [4, 13, 17]. Without IGRs, it has been demonstrated recently with ectoparasiticides containing afoxolaner, fluralaner or sarolaner, that a sustained high speed of kill can prevent egg production and thus avoid environmental contamination by immature flea stages [3, 7, 8, 19, 20]. …”

Fluralaner as a single dose oral treatment for Caparinia tripilis in a pygmy African hedgehog

“…Fluralaner is an isoxaline insecticide and acaricide with high activity, having the dual mechanisms of action of gamma aminobutyric acid and L‐glutamate chloride channel blockade in susceptible invertebrate parasites. It is highly selective for arthropods and has a wide margin of safety in vertebrates . It is approved for use in dogs and cats for flea and tick prevention in the USA, and efficacy has been reported in the treatment of Demodex spp .…”