The Zaire species of Ebolavirus (ZEBOV) remains the most virulent of the various known species. It alone is responsible for 88% of human deaths from haemorrhagic fever recorded since Ebola’s discovery in 1976. It was moreover the species involved in the two-month long epidemic which raged in the Democratic Republic of Congo (DRC) .In spite of the mass of scientific data collected during previous epidemics, the international scientific community has still not succeeded in determining the evolutionary development of the Ebolavirus and more particularly that of ZEBOV. Investigations were restricted by the scarcity of available data. Only 12 gene sequences coding for the glycoprotein (GP), a molecular structure that enables the virus to penetrate a cell before infecting it, have currently been identified. Furthermore, these sequences, isolated from infected humans between 1976 and 2001, appear to belong to a single genetic lineage originating from the first epidemic documented in the DRC in 1976. This apparent genetic uniformity therefore suggested that epidemics that broke out after 1976 all stemmed from the very first one. However, recent discoveries by a joint IRD-CIRMF team have called this hypothesis into question.