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

Heike Williams,Anja R Heckeroth,Hartmut Zoller,Tariq Qureshi,David R Young

doi:10.1186/1756-3305-7-275

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.

Highlights

Fluralaner, a novel isoxazoline, has both acaricidal and insecticidal activity through potent blockage of GABA- and L-glutamate-gated chloride channels
In vitro membrane-feeding exposure A membrane-feeding method [8] was modified to assess the impact of fluralaner exposure on flea reproduction
Each pen Impact on flea reproduction after in vitro membrane-feeding exposure Feeding exposure to concentrations of 50 ng fluralaner/mL resulted in a flea survival of 78.1%, 20.0%, 8.7% and 1.2%

Summary

Introduction

Fluralaner, a novel isoxazoline, has both acaricidal and insecticidal activity through potent blockage of GABA- and L-glutamate-gated chloride channels. Fluralaner is a new molecular entity of the isoxazoline class that has shown potent acaricidal and insecticidal activity through a dual mechanism of binding to neuronal GABA- and glutamate-gated chloride channels in susceptible invertebrates [1,2]. The adult population on the dog represents only approximately 5% of the total flea infestation in a dwelling, while the other 95% of the population consists of eggs, larvae and pupae in the dog’s home environment [6]. These maturing stages will re-infest the dog as they become adults

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