Ebola virus disease (EVD) is caused by Ebola virus – an increasingly frequent but unpredictable emerging deadly zoonotic disease in people and nonhuman primates, such as gorillas, chimpanzees and monkeys. The Ebola virus reservoir host species is unknown but is believed to include fruit bats. Transmission to humans frequently occurs through handling infected non-human primate carcasses.
There are six known Ebola virus species, four of which are known to cause EVD in humans. The virus is primarily located in sub-Saharan Africa. The average EVD case fatality rate is around 50% but varies based on the Ebola virus species, ranging from 25% to 90% in past outbreaks.
There are currently 2 licensed Ebola vaccines for humans, which both protect against the species Zaire ebolavirus.
The 2014-2016 outbreak in West Africa has been the largest and most complex outbreak to date. There were over 28,600 cases, with a tragic loss of over 11,300 lives. So far, $4.3 billion has been committed by external donors to fight Ebola in Sierra Leone, Guinea and Liberia.
US CDC – 2014-2016 Ebola outbreak in West Africa