Viral hemorrhagic fevers (VHFs) are a diverse group of infectious diseases characterized by fever and systemic damage to the circulatory system. Viral hemorrhagic fevers cause symptoms ranging from mild to life-threatening, depending on the virus involved, but generally cause internal bleeding that leads to sudden onset of muscle pain, fever, and hypotension. In severe cases, VHFs can cause life-threatening shock and bleeding from internal organs. Viral hemorrhagic fevers are caused by five known families of RNA viruses, although not every virus in these families causes hemorrhagic fever: Arenaviridae, Filoviridae, Flaviviridae, Hantaviridae, and Rhabdoviridae.