Variation in biting frequency by Anopheles mosquitoes can explain some of the heterogeneity in malaria transmission in endemic areas. In this study in Burkina Faso, we assessed natural exposure to mosquitoes by matching the genotype of blood meals from 1066 mosquitoes with blood from residents of local households. We observed that the distribution of mosquito bites exceeded the Pareto rule (20/80) in two of the three surveys performed (20/85, 76, and 96) and, at its most pronounced, is estimated to have profound epidemiological consequences, inflating the basic reproduction number of malaria by 8-fold. The distribution of bites from sporozoite-positive mosquitoes followed a similar pattern, with a small number of individuals within households receiving multiple potentially infectious bites over the period of a few days. Together, our findings indicate that heterogeneity in mosquito exposure contributes considerably to heterogeneity in infection risk and suggest significant variation in malaria transmission potential.

Rapid development of resistance in vector mosquitoes to synthetic insecticides is a major challenge for malaria control. The use of plant-derived essential oils (EOs) is an attractive strategy in controlling mosquito populations because they are environmentally safe and may have a lower chance of developing resistance. This study assessed the larvicidal activities of EOs from Lantana camara, Lippia multiflora, Lippia chevalieri, and Cymbopogon schoenanthus against Anopheles funestus and Culex quinquefasciatus. The 3^rd4^th instar larvae were tested using a World Health Organization (WHO)-modified protocol to evaluate larval mortality 24h after exposure to EOs and their binary combinations. Culex quinquefasciatus larvae were more susceptible to EOs than An. funestus larvae. For Cx. quinquefasciatus, the lethal concentrations at 50 mortality (LC₅₀s) of EOs from C. schoenanthus, L. multiflora, L. camara, and L. chevalieri were 23.32, 27.24, 38.54, and 54.11ppm, respectively; whereas for An. funestus, the EO LC₅₀s were 120.5, 67.5, 49.21, and 105.74ppm, respectively. Synergistic effects were observed using EOs from C. schoenanthus+L. multiflora (LC₅₀=44.05ppm) on An. funestus, while L. camara+L. chevalieri (LC₅₀=33.16ppm), L. chevalieri+C. schoenanthus (LC₅₀=12.08ppm), and L. multiflora+L. chevalieri (LC₅₀=20.61ppm) were synergistic for Cx. quinquefasciatus. These results indicate the potential of EOs derived from local plants and their binary combinations as botanical larvicides. The EOs could be used as future ecofriendly agents to control these vectors.