ABSTRACT
The first recognized human cases occurred in Zaire, now the Democratic Republic of Congo (DRC), in 1976 near the Ebola River. Whether the virus had caused human infections before that time is unknown. The similarity of the clinical manifestations to other hemorrhagic fever viruses and the limited capacity for identifying and reporting rare infections in the regions involved make it difficult to determine if this was a human pathogen earlier in the twentieth century. The West African Ebola epidemic of 2014–2016 raised many questions about the previously rare infection. Prior to this outbreak, however, Ebola virus was thought to be one of the rarest human pathogens, and strategies to contain outbreaks as large as that seen in 2014–2016 were lacking. The virus was known as a highly lethal agent that posed risk to those living in somewhat remote areas of East Africa and, perhaps, to health care and laboratory workers responding to outbreaks in that region.
