There are four types of the Ebola virus, three of which cause illness in humans. The exact origin, locations, and natural habitat of this virus remain unknown, but researchers believe it is normally maintained in an animal host that is native to the African continent. Person-to-person transmission occurs through direct contact with people who have Ebola, or direct contact with their body fluids. Ebola virus got its name from a river in the Democratic Republic of the Congo (formerly Zaire) in Africa, where it was first recognized.