Effect of Fluralaner on the biology, survival, and reproductive fitness of the Neotropical malaria vector Anopheles aquasalis

Abstract Reducing mosquito abundance or interfering with its ability to support the parasite cycle can help to interrupt malaria in areas of significant risk of malaria transmission. Fluralaner is a safe and effective drug for veterinary use indicated for the treatment against fleas and ticks which acts as an antagonist of chloride ion channels mediated by γ-aminobutyric acid (GABA), preventing the entry of these ions into the postsynaptic neuron, leading to hyperexcitability of the postsynaptic neuron of the central nervous system of arthropods. Fluralaner demonstrated insecticidal activity against different species. The study aimed to evaluate the effects of Fluralaner on the biology, survival, and reproductive fitness of Anopheles aquasalis. The following Lethal Concentrations (LC) were determined for An. aquasalis: LC5 = 0.511 µM; LC25= 1.625 µM; LC50= 3.237. A significant decrease (P<0.001) was evident in the number of eggs, larvae, and pupae in the group exposed to a sublethal dose of Fluralaner when compared to a control group (without the drug). Using blood from dogs after administration of Fluralaner, it was observed that the drug causes 100% mortality in An. aquasalis in less than 24 hours after feeding; this effect remains even after 90 days in all samples. In the drug-free group, Fluralaner showed the same result for up to 60 days, and after that, there was a slight reduction in its effect, evidenced by a decrease in the percentage of dead females. However, still significant when compared to the control group (P<0.001). Fluralaner affects the biology and reduction of survival in An. aquasalis in a lasting and prolonged period, and its fecundity with lower dosages, is a strong candidate for controlling disease vectors.