Coloured scanning electron micrograph (SEM) of Marburg virus particles (yellow) attached to the surface of an infected cultured cell (blue). This tubular RNA (ribonucleic acid) virus causes Marburg virus disease in humans and non-human primates. Symptoms of this rare and often fatal disease include high fever, headache, muscle pain, rash, nausea, diarrhoea and haemorrhaging. The virus was first documented in 1967 when there were simultaneous outbreaks of haemorrhagic fever in laboratories in Marburg and Frankfurt, Germany, and in Belgrade, Yugoslavia. The outbreak was traced to vervet monkey tissue used in research.