a, Temporally resolved phylogenetic tree of 792 EBOV genomes, colored according to reporting health zone. The health zone of internal nodes is inferred via a discrete model, and reduced confidence is conveyed by transitioning colors to gray. b, Geographical spread of samples over four disjoint time intervals spanning the entire outbreak. Figure adapted from Nextstrain visualizations. Note that three health zones—Manguredjipa (two samples), Rwampara (four samples) and Mwenga (four samples)—are located outside of the area on the map shown here.