Similar cases of hemorrhagic fever to Marburg virus were first identified in 1976, during an outbreak in two neighboring locations: first in southern Sudan and subsequently in northern Zaire, now Democratic Republic of the Congo.
An unknown causative agent was isolated from patients in both outbreaks and named Ebola virus. The disease was named after a river in the Democratic Republic of the Congo in Africa, where it was first recognized.
These two epidemics were caused by two distinct species of Ebola virus, Sudan Ebola virus and Zaire Ebola virus, a fact not recognized until years later.
Since then, five species have been isolated: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SUDV), Bundibugyo ebolavirus (BDBV) Taï Forest ebolavirus (TAFV) and Reston ebolavirus (RESTV).
Ebola strains that cause human disease include Ebola-Ivory Coast (isolated in 1994 from an infected ethnologist who had worked in the Tai Forest reserve in Côte d’Ivoire and had done a necropsy on a chimpanzee. The animal came from a troop that had lost several members to an illness later identified as Ebola hemorrhagic fever) and Ebola-Bundibugyo (isolated in 2007 during an outbreak in Uganda).
A case of Ebola-Sudan was reported in the United Kingdom in 1976 in a laboratory worker infected via the accidental stick of a contaminated needle, and a case of Ebola-Zaire was reported in South Africa in 1996 in a physician who had traveled to Johannesburg after treating Ebola virus–infected patients in Gabon.
In 2009, an outbreak of Reston Ebola virus was discovered in pigs in the Philippines, and antibody evidence of human infection was also found however the source has not been found.
Ebola hemorrhagic fever
