The family Filoviridae contains two genera, Marburgvirus and Ebolavirus, that consist of negative-sense, single-stranded RNA viruses capable of infecting humans. Ebolavirus has five species named for their original site of recognition, and Marburgvirus has two species.

• Both Marburg virus and Ebola virus are biosafety level 4 pathogens because of high mortality rates (except for Reston virus, an Ebola virus, which is nonpathogenic for humans) and aerosol infectivity.