Ebola hemorrhagic fever is a disease caused by one of five different Ebola viruses. Four of the strains can cause severe illness to humans and animals. The fifth, Reston virus, has caused illness to some animals, but not to humans. The Ebola virus is named after the Ebola River, where the virus was first recognized in 1976. There are 5 species that have been identified: Zaire, Bundibugyo, Sudan, Reston. The first 3, Bundibugyo ebola virus, Zaire ebola virus, and Sudan ebola virus have been associated with large outbreaks in Africa. The virus causing the 2014 west African outbreak belongs to the Zaire species. This emerging health threat is the result of a RNA (ribonucleic acid) virus that infects wild animals — like fruit bats, monkeys, gorillas, and chimpanzees — as well as people. Contact with an infected animal’s blood or body fluids is probably the original source of the infectious disease.