An Introduction to Ebola: The Virus and the Disease

A number of colleagues, both in the laboratory and in the field, agreed to prepare reports reflecting recent research, thus permitting this supplement to the Journal of Infectious Dis- Ebola, the Second Known Filovirus eases, which provides a single source for substantial new, peerreviewed information. We have somewhat arbitrarily divided Humans Meet Ebola Virus in Africa, 1976 the supplement into the categories of clinical observations; In the late 1970s, the international community was again epidemiology and surveillance; ecology and natural history; startled, this time by the discovery of Ebola virus [10] as the virology and pathogenesis; experimental therapy; control, re- causative agent of major outbreaks of hemorrhagic fever in the sponse, prevention; and conclusions. ‘‘Ebola,’’ however, is not Democratic Republic of the Congo (DRC) [11] and Sudan [12]. just one Ebola: There are 4 distinguishable subtypes, whose International scientific teams that arrived to deal with these phylogenetic tree is shown on page iii of this supplement [1 ‐ highly virulent epidemics found that transmission had largely 3]. Because the subtypes, which may even be different virus ceased; however, they could reconstruct considerable data from species, have differing properties, we have grouped the papers the survivors. Medical facilities had been closed because of by the subtype discussed within each subject area. the high death toll among the staff, thus eliminating major centers for dissemination of infection through the use of unsterilized needles and syringes and the lack of barrier-nursing techMarburg, the First Known Filovirus niques. In contrast, patients in the affected villages were segreBiomedical science first encountered the virus family Filovi- gated through traditional methods of quarantine, a step that ridae when Marburg virus appeared in 1967 [4]. At that time, controlled the situation outside the clinics. Much of the inforcommercial laboratory workers with a severe and unusual dis- mation concerning these outbreaks has been previously summaease were admitted to a hospital in Marburg, Germany. The rized [13]. attending physician recognized the distinctive clinical picture The international alarm and research efforts that arose in as additional cases appeared, and an investigation led to the response to these outbreaks quickly dwindled when the only isolation and identification of the immediate source of the virus convincing evidence that Ebola virus infections were continuas green monkeys imported from Africa for use in research ing among humans consisted of a small outbreak in the Sudan and vaccine production. The monkeys, some of which had been in 1979 [14] and 1 case in Tandala, DRC, in 1977 [15]. shipped to Frankfurt, Germany, and Belgrade, Yugoslavia, were euthanatized, and the epidemic was contained with only 31 human cases and one generation of secondary transmission Ebola Virus Visits the United States: The Virus Family Grows to health care workers and family members. Nevertheless, the In 1989, Ebola surprised us once more when it appeared in bizarre morphology of the virions, the 23% human mortality, monkeys imported into a Reston, Virginia, primate facility and the failure to identify the natural history of the virus left outside of Washington, DC. Epidemics in cynomolgus monfear among many who were concerned with the role of viruses keys (Macaca fascicularis) occurred in this facility and others in human economy. Quarantine procedures were put in place through 1992 [16 ‐ 17] and recurred in 1996, as reported in this