Viral hemorrhagic fevers include Ebola hemorrhagic fever, Marburg disease and Lassa fever. The etiologic agents of the diseases, Ebola virus, Marburg virus and Lassa virus, respectively, are categorized as viruses with biosafety level 4, because of their high mortality, high transmissibility and the lack of effective vaccines and therapeutic measures. Ebola and Marburg viruses are members of the Filoviridae family and easily distinguishable from viruses of other families by the characteristic morphology of the virion. The natural reservoir(s) of Ebola and Marburg viruses remain unknown. On the other hand, Lassa virus is a member of the Arenaviridae family and its natural reservoir is a kind of rodent of the Mastomys species, which are asymptomtically infected with the virus and continue to excrete the virus throughout their lifetime. Ebola, Marburg and Lassa viruses exist almost exclusively in Africa, with a minor fraction of Ebola virus being present in southeast Asia and possibly other tropical areas. However, these viruses can be imported to any part of the world industrialized countries. When attending patients with viral hemorrhagic fevers, "barrier nursing" using face shields (or goggles), masks, rubber gloves, etc., is recommended to avoid direct contact with blood and other body fluids of the patients.