 The viral strains fall into two clades—Ravn virus and Marburg virus.The Marburg strains can be divided into two—A and B.The A strains were isolated from Uganda (five from 1967), Kenya (1980) and Angola (2004–2005) while the B strains were from the Democratic Republic of the Congo epidemic (1999–2000) and a group of Ugandan isolates isolated in 2007–2009.