Ebola virus disease is a severe, often fatal illness caused by the Ebola virus. The virus was first discovered in 1976 near the Ebola River in the Democratic Republic of Congo. The 2014 outbreak in West Africa was the largest in history, infecting thousands and killing over 11,000. The virus is transmitted through direct contact with body fluids of infected humans or animals. Common symptoms include fever, headache, muscle pain and weakness. While there is no approved vaccine, treatment involves supportive care to improve symptoms.