This graph shows the Ebola transmission network within Sierra Leone, inferred by the new method. The arrows denote the sources of infection, color-coded by different transmission paths. Transmission paths in red originated in Western Area Urban and those in blue originated in Kailahun. The width of the arrow is proportional to contribution from the source (percentage associated with the end of each arrow) during the dates indicated next to the percentages. A solid arrow indicates all 300 simulation runs inferred the same path; a dashed arrow indicates only a portion of runs inferred a particular path; the transparency of an arrow also indicates the level of agreement among all runs; greater transparency implies less consensus among runs. Districts labelled in bold are inferred as initial sources of infection by all runs (those attached to solid arrows or no arrows for districts with sporadic cases) or only a fraction of the 300 runs (those attached to dashed arrows). Districts are colored by their population sizes (indicated in the legend).