In 1976 a bleeding fever erupted at once in northern Zaire and southern Sudan, killing the nurses and missionaries who cared for the sick. Karl Johnson and Patricia Webb, who had broken Machupo, helped identify a new virus in the Marburg family from the CDC's Special Pathogens Branch. Johnson named it for the Ebola River so the village of Yambuku would not be stigmatized.
The 1976 identification was shared by several laboratories and international teams, not a solo American effort. Contemporary death tolls shifted week to week, and scholars differ slightly on the river's name origin.