Machupo virus (MACV) is the etiological agent of Bolivian hemorrhagic fever (BHF) and a member of the family Arenaviridae. Members of the Arenaviridae family are enveloped, bi-segmented, negative-sense RNA viruses. The vector is the vesper mouse Calomys callosus, a rodent indigenous to northern Bolivia. Infected animals are asymptomatic and shed the virus in excreta, thereby infecting humans. Bolivian hemorrhagic fever (BHF) is a hemorrhagic fever. Symptoms include flushing of the head and torso, petechiae, hypotension, blood in vomit and stool, delirium, convulsions, tremors, bleeding gums, coma, and death. The mortality rate varies between outbreaks of BHF but is estimated to be around 25%.