ABSTRACT
The pattern of Ebola virus disease (EVD) before the 2014–2016 epidemic in West Africa was of sporadic outbreaks in rural areas of East and Central Africa involving a few dozen to a few hundred cases. Despite the understanding of the Ebola virus and EVD that was gained through investigation of these outbreaks, the West African epidemic of 2014–2016 again raised questions about the means of transmission and necessary steps for control. A disproportionate share of cases of EVD occurred among health care workers in West Africa. The West African outbreak was first recognized in the early spring of 2014, and it quickly grew to a magnitude never before seen. The initial cases of the outbreak were first recognized in West Africa in March 2014 and occurred in the adjacent countries of Guinea, Liberia, and Sierra Leone almost simultaneously.
