Epidemiology and pathogenesis of Ebola viruses

The Ebola viruses (EBOV) are enveloped, non-segmented, negative-sense, single-stranded RNA viruses, with size of genome approximately 19 kbp [2]. The virion is pleomorphic, producing ‘U’- shaped, ‘6’-shaped, or circular forms [3]. The EBOV may cause a disease in humans as well as in non-human primates, called Ebola virus disease (EVD). EBOV are firstly described in 1976, since than five species of the EBOV were described since. Four of them: Sudan virus (SUDV), Ebola virus (EBOV, known as Zaire), Taï Forest virus (TAFV), and Bundibugyo virus (BDBV) cause acute and lethal disease in human population [4, 5]. The fifth, Reston virus (RESTV), differs from each other, it has been caused disease only in monkeys, chimpanzees, and gorillas and it is apparently maintained in an animal reservoir in the Philippines and has not been found in Africa [6, 7]. Since 1976, more than twenty outbreaks of EVD have been reported in Africa [8]. The current outbreak, West Africa Ebola Outbreak 2014 (WAEO), first reported by the World Health Organization (WHO) on 22 March 2014, was caused by ZEBOV and is responsible for more than ten thousands death [9]. In addition to the three most affected countries in sub-Saharan Africa (Guinea, Liberia ad Sierra Leone), EBOV cases have been reported in the Great Britain, the United States and Spain [1, 10]. The behavior of WAEO was so alarming, that some countries decided to implement special measures for air plane transport of passengers from affected countries [11].

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