Fig. 3

Schematic representation of mosquito distribution in a typical rural habitat. The selective pressure on indoor mosquito populations resulting from the implantation of ITNs and IRS induce behavioural changes of mosquitoes that bite increasingly outdoors (1), earlier at dusk and/or later at dawn when humans are not protected (2). Mosquitoes may also feed more often on non-human hosts (3), and rest outdoors (4) to avoid exposure to vector control. Most WHO-approved tools currently focus on the control of indoor populations (blue boxes) and those that are in development or under interim approval follow the same trend (*), leaving few current options for scalable control of outdoor biting populations (www.who.int/vector-control/vcag/new-interventions/en/). *Interim approval; ** Pyrethroid-PBO net in areas with metabolic resistance