Three ebolavirus types have caused large outbreaks in sub-Saharan Africa: Zaire ebolavirus, Sudan ebolavirus, and the recently described Bundibugyo ebolavirus (Feldmann et al., 2011; Hartman et al., 2010). Epidemics have occurred in the Democratic Repubilc of Congo, Sudan, Gabon, and Uganda. The Reston ebolavirus which circulates in the Philippines has caused disease in nonhuman primates but not in humans (Miranda et al., 1999). The fifth species, Tai forest ebolavirus, was documented in a single human infection caused by contact with an infected chimpanzee from the Tai Forest in Ivory coast (Formenty et al., 1999). Although this event indicated the presence of Tai Forest ebolavirus in West Africa, this subregion was not considered to be an area in which Zaire ebolavirus was endemic.

On March 10, 2014, hospitals and public health services in Gueckedou and Macenta alerted the Ministry of Health of Guinea and 2days later - eight patients were hospitalized; three of them died, and additional deaths were reported among the families of the patients. Several deaths were reported in Macenta. This include deaths among hospital staff members.

As of September 14, 2014, a total of 4507 confirmed and probable cases of Ebola virus disease (EVD), as well as 2296 deaths from the virus, had been reported from five countries in West Africa - Guinea, Liberia, Nigeria, Senegal, and Sierra Leone. In terms of reported morbidity and mortality, the current epidemic of EVD is far larger than all previous epidemics combined. The true numbers of cases and deaths are certainly higher (World Health Organization).