Figure 3.

Protection “gap” when only indoor insecticide-based vector control measures are applied (adapted from Durnez and Coosemans [7]). For anophelines that blood feed both indoors and outdoors, the overwhelming majority of exposure events for an unprotected person may still occur indoors if mosquitoes actively seek blood throughout the night when most people are asleep inside their dwellings (A) or conducting outdoor activities during the night or early morning hours (B). Critical, site-specific data for contemporaneous entomological and human behavioral elements for quantifying the distribution of human exposure to malaria vectors across times of the night and indoor versus outdoor locations include entomological and human data. Entomological data at the local level include (1) directly comparable measurements of hourly indoor and outdoor biting rates by individual vector species over the full period of feeding activity and (2) reference estimates for the personal protection provided by insecticide-treated bed nets (ITNs) while they are actually being used, expressed in terms of proportional human blood feeding reduction. Human data at the local level include (1) local estimates of the proportions of the population who are indoors versus outdoors for each hour of the night (1800 to 0600 hours), (2) estimates of the proportion of population who are retired (asleep or trying to sleep) versus awake and active, for each hour of the night; and (3) estimates of the proportion of population using an ITN for each hour of the night [120]. Abbreviation: IRS, indoor residual spraying.