Viral hemorrhagic fever
A syndrome caused by infection with one of a number of viruses that can cause
increased permeability of the blood vessels resulting in bleeding into the skin,
internally, or from the mouth or other orifices. The bleeding is usually not lifethreatening.
Other signs and symptoms of viral hemorrhagic fever (VHF) may also
include high fever, weakness, dizziness, and myalgia. In severe cases, there may be
shock, coma, delirium, seizures , and death. The viruses that cause VHF belong to four
families: the arenaviruses, filoviruses, bunyaviruses, and flaviviruses. The arenaviruses
include the Lassa fever virus and Machupo, Junin, Guanarito, and Sabia hemorrhagic
fever viruses. Among the filoviruses are the notorious Ebola virus and Marburg virus.
Humans are infected when they come into contact with infected hosts. However, with
some of these viruses, after the transmission from the natural host, there can be
person-to-person transmission. Human cases or outbreaks of hemorrhagic fevers
caused by these viruses occur sporadically and irregularly. The occurrence of
outbreaks cannot be easily predicted. With a few exceptions, there is no established
drug treatment for VHFs. Ribavirin, an anti-viral drug, has been effective in treating
some patients with Lassa fever. Treatment for most of the VHFs is largely supportive.
The Lassa fever virus, Machupo virus, Ebola virus and Marburg virus are high-priority
bioterrorism agents – category A.