Ebola virus is the sole member of the Zaire ebolavirus species, and the most dangerous of the five known viruses within the genus ebolavirus. Four of the five known ebolaviruses cause a severe and often fatal hemorrhagic fever in humans and other primates, known as ebola virus disease.
The virus and its species were both originally named for Zaire (now the Democratic Republic of Congo), the country where it was first described, and was at first suspected to be a new "strain" of the closely related Marburg virus;
the virus was renamed to "ebola virus" in 2010 to avoid confusion. The species is a virological taxon species included in the genus Ebolavirus, family Filoviridae (whose members are called Filovirus, order Mononegavirales.
Its natural reservoir is believed to be bats, particularly fruit bats, and it is primarily transmitted between humans and from animals to humans, through body fluids.