Ebola first appeared in 1976 in two simultaneous outbreaks, in Nzara, Sudan, and in Yambuku, Democratic Republic of Congo. The latter was in a village situated near the Ebola River, from which the disease takes its name.
Formerly known as Ebola haemorrhagic fever, the disease is a severe, often fatal illness, with a case fatality rate of up to 90 percent.
It is one of the world's most virulent diseases. The infection is transmitted by direct contact with the blood, body fluids and tissues of infected animals or people. Severely ill patients require intensive supportive care.
During an outbreak, those at higher risk of infection are health workers, family members and others in close contact with sick people and deceased patients.
Ebola virus disease outbreaks can devastate families and communities, but the infection can be controlled through the use of recommended protective measures in clinics and hospitals, at community gatherings, or at home.