Marburg virus, coloured atomic force micrograph (AFM). This particle is showing the characteristic shepherd's crook shape. This RNA (ribonucleic acid) virus causes Marburg haemorrhagic fever in humans and non-human primates. Symptoms of the rare disease, which is often fatal, include fever, muscle pain, rash, diarrhoea and haemorrhage. The virus was first documented in 1967 when there were simultaneous outbreaks of haemorrhagic fever in laboratories in Marburg and Frankfurt, Germany and Belgrade, Yugoslavia. The outbreak was traced to vervet monkey tissue used in research. Magnification: x86,000 when printed at 10 centimetres wide.