The past, present and threatened future of residual malaria transmission

Dr Gerry Killeen.  Reader Liverpool School of Tropical Medicine, based at Ifakara Health Institute, Tanzania

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 (HICs) 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 under-utilized in LMICs.

Programmatic development and evaluation of decentralized, locally-managed systems for delivering these pro-active mosquito population abatement practices in LMICs could therefore enable broader scale up.

Furthermore, a diverse range of emerging or re-purposed 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 mobilize 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.

Dr Killeen is a Reader at the Liverpool School of Tropical Medicine, who has been based at the Ifakara Health Institute (IHI) in Tanzania for the last 13 years. He works on a variety of basic and applied aspects of malaria transmission control, especially vector control, with a strong emphasis upon developing new interventions and capacity strengthening at individual, systems and institutional levels.