The 2014 Ebola epidemic is the largest in history, affecting multiple countries(http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/distribution-map.html#areas) in West Africa

Ebola hemorrhagic fever is a disease caused by one of five different Ebola viruses. Four of the strains can cause severe illness in humans and animals. The fifth, Reston virus, has caused illness in some animals, but not in humans.

The first human outbreaks occurred in 1976