Dictionary.net

a severe and often fatal disease in humans and nonhuman primates (monkeys and chimpanzees) caused by the Ebola virus; characterized by high fever and severe internal bleeding; can be spread from person to person; is largely limited to Africa

A highly fatal, acute hemorrhagic fever, clinically very similar to MARBURG VIRUS DISEASE, caused by the EBOLA VIRUS, first occurring in the Sudan and adjacent northwestern (what was then) Zaire. The natural reservoir and mode of transmission of the virus are unknown, but secondary infection is by direct contact with infected blood and other body secretions. (From Dorland, 28th ed)