Figure 2. Incidence (cases/100 person-years) of influenza-like illness (ILI) in a cohort of children in Nicaragua, showing seasonal peaks, April 16, 2005–April 15, 2006, and April 16, 2006–April 15, 2007. A) Incidence of ILI episodes per calendar week. B) Incidence of high-probability ILI episodes per calendar week. C) Incidence of ILI in children 6–12 years of age per calendar week. All curves were smoothed by Lowess (19) by using a 3-week moving average.