Ebola virus disease (EVD; also Ebola hemorrhagic fever, or EHF), or simply Ebola, is a disease of humans and other primates caused by ebolaviruses. Signs and symptoms typically start between two days and three weeks after contracting the virus as a fever, sore throat, muscle pain and headaches. Then, vomiting, diarrhea and rash usually follow, along with decreased function of the liver and kidneys. At this time some people begin to bleed both internally and externally. Death rates can vary widely, but death occurs in about 50% of cases, often due to low blood pressure from fluid loss, and typically follows six to sixteen days after symptoms appear.
The virus spreads by direct contact with blood or other body fluids of an infected human or other animal.Infection with the virus may also occur by direct contact with a recently contaminated item or surface.Spread of the disease through the air has not been documented in the natural environment.EBOV may be spread by semen or breast milk for several weeks to months after recovery. African fruit bats are believed to be the normal carrier in nature, able to spread the virus without being affected by it. Humans become infected by contact with the bats or with a living or dead animal that has been infected by bats. After human infection occurs, the disease may also spread between people. Other diseases such as malaria, cholera, typhoid fever, meningitis and other viral hemorrhagic fevers may resemble EVD. Blood samples are tested for viral RNA, viral antibodies or for the virus itself to confirm the diagnosis.