Efficacy of fluralaner, a long acting acaricide against three species of vector mosquitoes (Diptera: Culicidae) under laboratory conditions – a potential candidate for drug based vector control

Abstract

Abstract Vector control is a key intervention against mosquito borne diseases such as dengue, chikungunya and malaria. However, conventional methods have several limitations and alternate strategies are in urgent need. Vector control with endectocides or systemic insecticides such as ivermectin is emerging as a novel strategy. The short half-life of ivermectin is a limiting factor for its application as a mass therapy tool for vector control. Isoxazoline compounds like fluralaner, a class of veterinary acaricides with long half-life hold promise as alternatives to ivermectin. These drugs persist in the animal body at detectable blood levels up to three months or more, after a one-time oral administration. However, information about their mosquitocidal effect is very much limited. In the current study, we explored the efficacy of fluralaner against laboratory reared vector mosquitoes of Aedes aegypti (Linnaeus, 1762), Anopheles stephensi (Liston, 1901) and Culex quinquefasciatus (Say, 1823) (Diptera: Culicidae) by blood feeding. Fluralaner showed significant mosquitocidal effect with the estimated 24 h LC50 values in the range of 24.04–49.82 ng/mL for the three different mosquito species tested. Effects on life history characteristics (fecundity, egg hatch success, immature development and adult emergence success) were also observed at drug concentrations nearing 24 h LC50. At higher drug concentration of 250 ng/mL, significant knock down effect was observed within 1–2 h post blood feeding. Potent mosquitocidal effect coupled with its long half-life makes fluralaner an excellent candidate for drug based vector control strategies especially in the context of “One Health” approach. In this regard, further studies on the safety aspects of fluralaner in humans are desirable.