What is Ebola hemorrhagic fever? Ebola hemorrhagic fever (Ebola HF) is a severe, often-fatal disease in humans and nonhuman primates (monkeys and chimpanzees) that has appeared sporadically since its initial recognition in 1976. The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of the Congo (formerly Zaire) in Africa, where it was first recognized. The virus is one of two members of a family of RNA viruses called the Filoviridae. Three of the four subtypes of Ebola virus identified so far have caused disease in humans: Ebola-Zaire, Ebola-Sudan, and Ebola-Ivory Coast. The fourth, Ebola-Reston, has caused disease in nonhuman primates, but not in humans.Where is Ebola virus found in nature? The exact origin, locations, and natural habitat (known as the"natural reservoir") of Ebola virus remain unknown. However, on the basisof available evidence and the nature of similar viruses, researchers believe thatthe virus is zoonotic (animal-borne) and is normally maintained in an animal host that is native to the African continent. A similar host is probably associated with the Ebola-Reston virus subtype isolated from infected cynomolgous monkeys that were imported to the United States and Italy from the Philippines. The virus is not known to be native to other continents, such as North America. Where do cases of Ebola hemorrhagic fever occur? Confirmed cases of Ebola HF have been reported in the Democratic Republic of the Congo, Gabon, Sudan, and the Ivory Coast. An individual withserologic evidence of infection but showing no apparent illness has beenreported in Liberia, and a laboratory worker in England became ill as a resultof an accidental needle-stick. No case of the disease in humans hasever been reported in the United States. Ebola-Reston virus caused severeillness and death in monkeys imported to research facilities in the UnitedStates and Italy from the Philippines; during these outb...
