Quantifying ivermectin's optimal strategy impacts on malaria transmission: a dual-structured mathematical model

Ivermectin (IVM), used alongside mass treatment strategies, has been suggested as a potential tool for reducing malaria transmission. The effectiveness of IVM in shortening vector lifespan depends on the time elapsed between the administration of IVM to the host and the blood meal taken by the vector. This effectiveness is measured by the median effective dose ( ED₅₀ ED50), the IVM concentration required to kill 50% of mosquitoes after a specific host exposure period. We use a mathematical model structured by human and vector exposure times to IVM and the model's well-posedness is established through semigroups theory. We calculate the basic reproduction number, linking it to epidemiological dynamics, and show steady states bifurcate at R₀=1 R0=1, governed by a constant Cbif Cbif. We identify the optimal human exposure to IVM and intervention interval to reduce prevalence by 10% to 20%. This depends on the IVM formulation ( ED₅₀ ED50) and the target number of campaigns in the host population.