This correspondence from the WHO Ebola Response Team focuses on the West African ebola epidemic after one year. It explains how the uneven success of ebola control measures to date, in the face of shifting geographic patterns of transmission, illustrates the continuing threat posed by the Ebola virus 1 year after the start of the epidemic. A total of 625 confirmed or probable cases were reported from Guinea, Liberia, and Sierra Leone in the first week of December, a number similar to the average for the preceding 10 weeks (667), but these cases are now spread over a wider geographic area. The worst fears of persistent exponential growth beyond September were not realised; nevertheless, Ebola still presents a huge challenge as we move into the second year of the epidemic in West Africa.