Insecticide resistance and its impact on vector control

Insect disease vector control is primarily based on the use of synthetic insecticides that are used either for indoor residual spraying (IRS) or the treatment of fabrics, particularly bed nets. As yet, there are still only four classes of public health insecticides available for most insect vector-borne diseases including malaria: pyrethroids, organochlorines, organophosphates (OPs) and carbamates. Whilst extensive deployment of long-lasting insecticide-treated bednets (LLINs), which are dependent on pyrethroids, is a contributing factor in the dramatic spread of pyrethroid resistance across Africa, the implementation of front-line alternatives such as carbamates is already being affected by resistance. The limited numbers of insecticides available and the speed at which insecticide resistance can take hold lead to fundamental questions about mechanisms of resistance, impact on vector control and ways to overcome insecticide resistance. The global plan for insecticide resistance management in malaria vectors (GPIRM) is a rallying call from the World Health Organization (WHO) to tackle these questions. Great strides have been made in identifying enzymes associated with insecticide metabolism in mosquitoes and applying new technology for monitoring and predicting resistance. This chapter explores the impact of insecticide resistance on vector control and recent developments in resistance research.