The Ebola virus disease (EVD), previously referred to as Ebola hemorrhagic fever, is a severe and often fatal infection. It is spread through contact with infected blood or bodily fluids.
Ebola virus disease was first identified in 1976 in Sudan and the Democratic Republic of the Congo (formerly Zaire). It is named after a river in the Democratic Republic of the Congo. Since its discovery, there have been several Ebola outbreaks, primarily limited to remote villages near tropical rainforests in Central and West Africa. As a result of the remoteness of the locations in which most of the outbreaks have occurred, the number of victims has been limited. The 2014 outbreak of Ebola virus disease has been one of the largest in documented history, in terms of both the number of cases and the geographical spread.
There have been 5 identified species of the ebolavirus genus, with 3 of them having caused previous EVD outbreaks. The 2014 outbreak is caused by the Zaire species, the most deadly strain, with a historic fatality rate of up to 90%.