Ebola virus. Coloured scanning electron micrograph (SEM) of Ebola virus particles (virions, yellow). Filamentous virions are being released vertically from the cell surface of an infected vero mammalian kidney epithelial cultured cell. Ebola virus disease, formerly known as Ebola haemorrhagic fever, is a rare but severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. Magnification: x9000, when printed 10 cm wide. Specimen courtesy of Greg Towers, UCL.