Bats are suspected of being a natural reservoir of Ebola virus. They can contaminate humans directly, without the intermediary of a secondary host such as great apes. IRD researchers and their partners recently found a strong correlation between the annual migrations of fruit bats and the 2007 Ebola fever epidemic in the Democratic Republic of the Congo (DRC) which killed nearly 200 people. Their investigations retraced the sequence of events that could have led to this epidemic. They discovered how all the conditions coincided to enable the virus to spread in humans. Ebola, which induces haemorrhagic fever, has been raging for 30 years in Africa. Since 2001, several epidemics have broken out in DRC, hitting both humans and great apes. This survey points the way to better prediction of future epidemics.