Figure 4

Location of the space-time primary cluster (Kulldorff statistic was significant at P < 0.01, shaded) of P. falciparum prevalence in Gezira state from 1999 to 2009. Shown also are the spatial only primary clusters for each year (circles with broken red boundaries). Except for the spatial-only cluster in 2007 (northwest of Gezira, on the western side of the Blue Nile), all other spatial-only clusters either overlapped or were contained with the primary space-time cluster.