Virus responsible for a severe and often fatal hemorrhagic fever .
Outbreaks in primates, including humans, have been recorded. Initial symptoms are fever, severe headaches and muscle aches, and loss of appetite; blood clots and profuse uncontrollable hemorrhaging appear within days, followed by nausea, vomiting, and diarrhea. Death occurs in 8–17 days; fatality rates range from 50% to 90%. There is no known treatment. It takes its name from the Ebola River in northern Congo (Zaire), where it first emerged in 1976. The virus appears as long filaments, sometimes branched or intertwined. The virus particle contains one molecule of RNA. How it attacks cells is unknown. It can be transmitted through contact with bodily fluids; unsanitary conditions and lack of adequate medical supplies have been factors in its spread.