Filovirus is the single genus in the family Filoviridae of the order Mononegavirales. Members of this group of RNA viruses cause sporadic episodes of severe hemorrhagic disease in human and nonhuman primates. The best-known filoviruses are the Ebola virus and Marburg virus. New strains of filoviruses continue to be recognized, mostly but not exclusively in Africa.
Marburg virus was isolated in 1967, from an outbreak that occurred in Marburg, Germany, when laboratory workers were exposed to infected tissue from monkeys imported from Uganda. Ebola virus was first isolated from humans during concurrent outbreaks of viral hemorrhagic fever in northern Zaire (now the Democratic Republic of Congo) and southern Sudan in 1976. An Ebola outbreak occurred in Zaire from January to June 1995, killing over 200 people.
The first symptoms of Ebola infection include fever, headache, chills, aching muscles, and malaise. More serious manifestations then follow: severe abdominal pain, vomiting, and diarrhea. In over half the cases the infected person begins to hemorrhage from many parts of the body, resulting in death. Although the risk of infection after direct exposure to infectious blood or other bodily fluids from obviously sick patients is high, transmissibility from infected humans who do not appear ill to other humans seems to be low. This factor makes containment of the disease a much more feasible task.