Figure 6

The importance of early cases in Burkina Faso and in a basic Susceptible-Infected model. (Left) A – Relationship between the number of cases during the peak months (from January to April) and the number of early cases (from October and December). C – Relationship between the number of early cases (from October and December) and the timing of the peak month (the month with the highest number of cases). To produce the panels A and C, we use monthly cases in Burkina Faso from 1961 to 2005 (the longest complete monthly time series). (Right) B – Sensitivity of the final number of infected individuals to the increase of the initial number of infected individuals in a basic Susceptible-Infected (SI) model. D – Relationship between the initial number of infected individuals and the timing of the peak month (the month with the highest number of cases) in the SI model. The SI model is mainly used here for an illustrative purpose.