Quantifying the impact of insecticide resistance in the transmission dynamics of malaria

The fitness cost imposed by insecticide resistance on malaria vectors has appeared as an asset for vector control despite the evolution and spread of insecticide resistance. However, certain levels of insecticide resistance intensity may reduce the efficacy of insecticide-treated nets for certain coverage levels. In this study, we consider a non-autonomous mathematical model for malaria transmission that investigates the impact of the interaction between the intensity of resistance, the coverage of insecticide-treated nets and the fitness cost of resistance on resistant vectors (fitness disadvantage or decreased performance) on the transmission dynamics of malaria. It is shown that the disease-free periodic solution of the model is globally attractive if the time-dependent reproduction number (R-T (t) < 1). The model also admits a unique positive periodic solution when R-T (t) > 1. We numerically studied the interaction between the fitness cost imposed by resistance on resistant vectors, the intensity of resistance and bed-net coverage. We observed that the intensity level present in the population may significantly affect the impact of the fitness cost that resistance imposes on resistant mosquitoes as well as reduce the effectiveness of control measures. (C) 2020 Elsevier Ltd. All rights reserved.