The 2013–2016 outbreak of Ebola virus disease, centered in Western Africa, was the most widespread outbreak of the disease in history and caused major loss of life and socioeconomic disruption in the region, mainly in Guinea, Liberia and Sierra Leone. The first cases were recorded in Guinea in December 2013; later, the disease spread to neighbouring Liberia and Sierra Leone, with minor outbreaks occurring elsewhere. It caused significant mortality, with the case fatality rate reported which was initially considerable, while the rate among hospitalised patients was 57–59%, the final numbers 28,616 people, including 11,310 deaths, for a case-fatality rate of 40%. Small outbreaks occurred in Nigeria and Mali, and secondary infections of medical workers occurred in the United States and Spain. In addition, isolated cases were recorded in Senegal, the United Kingdom and Italy. The number of cases peaked in October 2014 and then began to decline gradually, following the commitment of substantial international resources.