The impacts of selection pressure on insecticide resistance in malaria vectors – a literature review

Vector control is key to the reduction and elimination of malaria. Indoor residual spraying (IRS), insecticide-treated nets (ITNs), and larviciding are examples of chemical control of malaria vectors. Conversely, the effectiveness of these approaches are currently under threat due to the emergence and global spread of resistance to the four major insecticide classes: pyrethroids, carbamates, organophosphate, and organochlorine. In this review, the mechanisms of resistance to these classes of insecticides include: target site inactivation, metabolic resistance, cuticle thickening, behavioural resistance, and xenobiotic sequestration. Consequently, the excessive use of insecticides, as well as other environmental factors such as agriculture, microbiome, natural xenobiotics, climatic factors, edaphic factors, and anthropogenic activities, have created selective pressure that constantly drives the emergence and intensification of insecticide resistance among Anopheles mosquitoes.