Figure 4From: Epidemiological changes in meningococcal meningitis in Niger from 2008 to 2011 and the impact of vaccination Geographical extension of N. meningitidis serogroup A (Nm A) from 2008 to 2009, its decline from 2010 to 2011 and, in parallel, the extension of Nm W in 2010 and 2011. The proportions of Nm A cases/Nm W cases per district are represented by coloured pie charts.Back to article page