The genus Marburgvirus includes a single species, Marburg marburgvirus (formerly referred to as Lake Victoria marburgvirus) [39, 40] . Phylogenetic analysis based on genomic sequence data suggests that the known members of this species can be assigned to at least five different lineages of which four are very closely related (nucleotide sequences differ up to 7%) while the fifth is divergent (a nucleotide difference of 21%) ( Figure 1b) [10, 22, 39] . As the genomic divergence between all isolates is below 30%-the cutoff for the classification of the five different ebolaviruses into five different species-the five marburgvirus lineages were recently reclassified as two viruses. Ravn virus (RAVV) is represented by the Ravn isolates from 1987, one isolate from the DRC outbreak in 1998-2000, and one human and several bat isolates from infections that took place in Uganda in 2007. Marburg virus (MARV) is represented by all other sequenced isolates ( Figure 1b , Table 1 ) [39] . For the sake of simplicity, in this review the abbreviation "MARV" is used for all marburgviruses and the abbreviation "EBOV" for all ebolaviruses.