Leech leech

Ebola is a virus of the family Filoviridae that is responsible for a severe and often fatal viral hemorrhagic fever; outbreaks in primates such as gorillas and chimpanzees as well as humans have been recorded. The disease is characterized by extreme fever, rash, and profuse hemorrhaging. In humans, fatality rates range from 50 to 90 percent.

The virus takes its name from the Ebola River in the northern Congo basin of central Africa, where it first emerged in 1976. Outbreaks that year in Zaire (now Congo [Kinshasa]) and The Sudan resulted in hundreds of deaths, as did another outbreak in Zaire in 1995. Ebola is closely related to the Marburg virus, which was discovered in 1967, and the two are the only members of the Filoviridae that cause epidemic human disease. A third related agent, called Ebola Reston, caused an epidemic in laboratory monkeys in Reston, Virginia, but apparently is not fatal to humans.