Abstract
Background : To sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommendsthe combination of effective tools. Before designing and implementing additional strategies in any setting, it iscritical to monitor or predict when and where transmission occurs. However, to date, very few studies havequantified the behavioural interactions between humans andAnophelesvectors in Africa. Here, we characterizedresidual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used. Methods : We analysed data on both human and malaria vectors behaviours from 27 villages to measure hourlyhuman exposure to vector bites in dry and rainy seasons using a mathematical model. We estimated the protectiveefficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users wereexposed to vector bites.Results:The percentage of the population who declared sleeping under a LLIN the previous night was very highregardless of the season, with an average LLIN use ranging from 92.43 to 99.89%. The use of LLIN provided > 80%protection against exposure to vector bites. The proportion of exposure for LLIN users was 29–57% after 05:00 and0.05–12% before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90%for children under 5 years old in the dry cold season. Conclusions : LLINs are predicted to provide considerable protection against exposure to malaria vector bites in therural area of Diébougou. Nevertheless, LLIN users are still exposed to vector bites which occurred mostly indoors inlate morning. Therefore, complementary strategies targeting indoor biting vectors in combination with LLIN areexpected to be the most efficient to control residual malaria transmission in this area.