Distribution of mosquito vectors across three theoretical scenarios.

A. When the whole population has access to treatment and are included in surveillance, with participation controlled by adherence. Vectors are also distributed evenly across the population, so everyone has the same risk of being bitten/ infected. B. The population is separated based on who has access to treatment and is included in surveillance, but those excluded are not at any higher risk of contracting disease. C. Those excluded are also more likely to be bitten/ infected therefore harbouring more disease than in the group with access to treatment, who are less likely to be bitten. Human outlines attributed to Microsoft.