Viral hemorrhagic fevers are a group of diseases caused by viruses from four families of viruses: filoviruses, arenaviruses, flaviviruses, and bunyaviruses. The usual hosts for most of these viruses are rodents or arthropods (such as ticks and mosquitoes). In some cases, such as Ebola virus, the natural host for the virus is unknown. All forms of viral hemorrhagic fever begin with fever and muscle aches. Depending on the particular virus, the disease can progress until the patient becomes very ill with respiratory problems, severe bleeding, kidney problems, and shock. The severity of viral hemorrhagic fever can range from a mild illness to death. The Ebola virus is a member of a family of RNA viruses known as filoviruses. Ebola virus was discovered in 1976 and was named for a river in Zaire, Africa, where it was first found. Until recently, only three outbreaks of Ebola hemorrhagic fever among people had been reported. The first two outbreaks were in 1976: one in Zaire and one in western Sudan. These were large outbreaks, causing more than 550 cases and 340 deaths. The third outbreak, in 1979 in Sudan, was smaller, with 34 cases and 22 fatalities. During each of these outbreaks, a majority of cases occurred in hospital settings under the challenging conditions of the developing world. These conditions, including a lack of medical supplies and the frequent reusing of needles and syringes, played a major role in the spread of disease. The outbreaks were quickly controlled when appropriate medical supplies and equipment were made available and quarantine procedures were used. The source of the Ebola virus in nature remains unknown. In an attempt to identify the source, investigators tested thousands of specimens from animals captured near the outbreak areas, but their efforts were unsuccessful. Monkeys, like humans, appear to be susceptible to infection. The one thing knowne by scientists which may bring us closer to discovering its car...
