Zaire Ebola virus (EBOV) is a fatal human pathogen, with a high case fatality rate (CFR) averaging up to 78%. In March 2014, the World Health Organization (WHO) was made aware of a ZEBOV outbreak in rural Guinea, West Africa. Epidemiologic investigation linked the clinical and laboratory confirmed cases with the presumed first fatality of the outbreak in December 2013. EBOV from Guinea is a separate clade from other ZEBOV strains reported from the Democratic Republic of Congo (DRC) and Gabon. Since the outbreak in March, ZEBOV was also reported in Conakry, Guinea's capital and spread to other neighboring countries. In its largest outbreak, ZEBOV disease expanded through Guinea, Liberia, Sierra Leone, and Nigeria and to Spain, the USA, and the UK. The WHO declared the 2013-2015 West African Ebola epidemic a public health emergency of international concern considering its presumable capacity for further international spread. Early manifestations of EVD (Ebola virus disease) include a high fever, body aches, malaise, and fatigue. Severe diarrhea and other gastrointestinal manifestations such as vomiting were common, while bleeding was a more sporadic finding. The fatality rate was 43% and highest in patients aged > or = 45 years and the overall fitted mean incubation period was 10.3 days (95% CI 9.9~10.7). We present a review of the literature on the emergence of Ebola, and the epidemiologic, clinical, and laboratory records of patients in whom EVD was diagnosed in Sierra Leone, Guinea, Liberia, Mali, the USA, and Spain, its zoonotic origin, and the transmission of ZEBOV, as well as presenting original literature on the current Ebola outbreak.