7 Essential Words of Fall
any of a variety of highly fatal viral diseases that are characterized by massive external or internal bleeding or bleeding into the skin. Other symptoms vary by the type of viral hemorrhagic fever but often include fever, malaise, muscle aches, vomiting, and shock. Most viral hemorrhagic fevers are geographically restricted because they are transmitted by specific animal or insect hosts (reservoirs) that occupy narrow and sometimes localized ecological niches. Viral hemorrhagic fevers are caused by viruses of four families: Flaviviridae, Arenaviridae, Bunyaviridae, and Filoviridae.