Two months after the start of the Sudan emergence—the time was now early September 1976—an even more lethal filovirus emerged five hundred miles to the west, in a district of northern Zaire called Bumba Zone, an area of tropical rain forest populated by scattered villages and drained by the Ebola River. The Ebola Zaire strain was nearly twice as lethal as Ebola Sudan. It seemed to emerge out of the stillness of an implacable force brooding on an inscrutable intention. To this day, the first human case of Ebola Zaire has never been identified.
