In the history of medicine, mention of acute hemorrhagic fever dated 1976, the first cases of lethality described in Zaire, the Ebola region. It is the source of the outbreak gave its name to the disease and the viral agent. The causative agent of hemorrhagic fever is an RNA-containing filovirus Ebola family of Filoviridae, which includes two more such dangerous species as the Marburg and Llovio. In addition, the Ebola virus has 5 subtypes: Zaire, Bundibugyo, Renston, Sudan and tai forest. Each of them causes hemorrhagic fever, but they differ in their properties and the severity of clinical symptoms. The frequency of deaths from flaviviruses reaches 90 %.