ABSTRACT
Viral hemorrhagic fever (VHF) is a virus-induced syndrome with a variable incubation period, followed by a prodromal period. The prodromal period is characterized by a nonspecic inuenzalike illness. Some patients recover uneventfully, whereas others develop more severe symptoms that may include edema, hemorrhage, hypotension, circulatory collapse, and neurological signs. Humans are infected with VHF viruses through close contact with other infected people through mucous membranes, broken skin, aerosolization, and inhalation or through contact with reservoir hosts depending on the virus (Čumakov, 1950; Gajdusek, 1962). Several viruses assigned to the families Filoviridae (loviruses) and Arenaviridae (arenaviruses) cause VHFs with extraordinarily high lethality in human populations. Absolute lethal case numbers usually range only in the lower hundreds during disease outbreaks, but the environmental and ecological factors that lead to outbreaks are poorly understood (Rollin et al., 2007). Consequently, there is concern that these viruses may spread and cause more substantial outbreaks in the future. At the same time, there is little to none that can be done for patients infected with loviruses or arenaviruses other than supportive care (loviruses) (Bausch et al., 2008) and application of convalescent immune sera or ribavirin (arenaviruses) (Charrel et al., 2011). The lack of therapy combined with the lack of generally approved or available vaccines may cause interest in these viruses among terrorist groups or hostile state actors, making the development of medical countermeasures against and general research on loviruses and arenaviruses top priorities among biodefense professionals (Borio et al., 2002). Filovirus and arenavirus diseases occur sporadically in rural and/or underdeveloped areas in Africa or South America. This means that human clinical and pathological data are rarely collected with the most up-to-date technology. This, in turn, poses a problem for countermeasure development, as novel candidate antivirals or vaccines against lovirus and arenavirus diseases cannot be tested in
2.1 Introduction ............................................................................................................................ 15 2.2 Filoviruses .............................................................................................................................. 16
2.2.1 In Humans .................................................................................................................. 16 2.2.2 In Nonhuman Primates ...............................................................................................20
