Let’s start with the most widespread epidemic of Ebola virus disease (known as Ebola). It is spreading out in West African. It has caused significant mortality, with a reported case fatality rate of about 71%.It began in Guinea in December 2013. Then spread to Liberia and Sierra Leone. A small outbreak of twenty cases occurred in Nigeria and one case occurred in Senegal; both countries were declared disease-free on 20 October 2014. Several cases have been reported in Mali.Imported cases in the United States and Spain have led to secondary infections of medical workers but have not spread further.An independent Ebola outbreak in the Democratic Republic of the Congo that started in August 2014 has been shown by genetic analysis to be unconnected to the main epidemic.