A syndrome that occurs in perhaps 20-40% of infections by a number of different viruses of the families Arenaviridae (Lassa fever, Bolivian haemorrhagic fever, Argentinean haemorrhagic fever), Bunyaviridae (Crimean-Congo haemorrhagic fever), Flaviviridae (Dengue haemorrhagic fever, Omsk haemorrhagic fever), Filoviridae (Ebola fever, Marburg virus d...