Developing an expanded vector control toolbox for malaria elimination

Abstract

Vector control using long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) accounts for most of the malaria burden reductions achieved recently in low and middle-income countries (LMICs). LLINs and IRS are highly effective, but are insufficient to eliminate malaria transmission in many settings because of operational constraints, growing resistance to available insecticides and mosquitoes that behaviourally avoid contact with these interventions. However, a number of substantive opportunities now exist for rapidly developing and implementing more diverse, effective and sustainable malaria vector control strategies for LMICs. For example, mosquito control in high-income countries is predominantly achieved with a combination of mosquito-proofed housing and environmental management, supplemented with large-scale insecticide applications to larval habitats and outdoor spaces that kill off vector populations en masse, but all these interventions remain underused in LMICs. Programmatic development and evaluation of decentralised, locally managed systems for delivering these proactive mosquito population abatement practices in LMICs could therefore enable broader scale-up. Furthermore, a diverse range of emerging or repurposed technologies are becoming available for targeting mosquitoes when they enter houses, feed outdoors, attack livestock, feed on sugar or aggregate into mating swarms. Global policy must now be realigned to mobilise the political and financial support necessary to exploit these opportunities over the decade ahead, so that national malaria control and elimination programmes can access a much broader, more effective set of vector control interventions.

Figure 1

Schematic illustration of malaria vector mosquito life histories, highlighting the most important behaviours that mediate residual transmission of malaria despite high coverage with long-lasting insecticidal nets and indoor residual spraying, as well as the many intervention opportunities that remain to be exploited with existing or emerging vector control methods. This figure has been updated relative to a previous version, to reflect evidence for the inclusion of additional intervention options, specifically odour-baited traps and targets for killing host-seeking mosquitoes (box 2), as well as targeted space spraying of mosquitoes (box 1), especially when they aggregate into mating swarms (box 3).