Ebola virus disease (EVD) is a life-threatening disease with sporadic outbreaks arising mainly on the African continent. EVD most often affects both humans and non-human primates (such as monkeys, gorillas, and chimpanzees). It is caused by infection with a group of viruses in the EbolavirusOf these, only four (Ebola, Sudan, Taï Forest and Bundibugyo viruses) are known to cause disease in humans. Reston virus is known to cause disease in non-human primates and pigs, but not in humans. It is not clear if the Bombali virus, recently found in bats, induces disease in either animals or humans.
The Ebola virus was first found along the Ebola River in 1976 in what is now the Democratic Republic of Congo. Since then, people have become infected with the virus from time to time, leading to outbreaks in many African countries. Scientists do not know where the Ebola virus is originating from. However, based on the existence of related viruses, they conclude that the virus is animal-born, with or without bats.