Ebola: a timeline of a ruthless killer
Dakar - Below are the main developments since the worst-ever epidemic of the haemorrhagic fever Ebola emerged in west Africa at the start of the year, fuelling fears it could spread to other continents.
22: Guinea identifies the Ebola virus as the source of a highly contagious epidemic raging through its southern forests, as the death toll rises to 59.
Experts had been unable to identify the disease, whose symptoms were first observed six weeks ago, but scientists studying samples in the French city of Lyon confirmed it was Ebola.
27: Ebola spreads to Guinea's capital Conakry.
31: Liberia confirms two cases of the virus.
5: West African countries mobilise against an epidemic of haemorrhagic fevers, including Ebola. The measures include the deployment of medical teams at Conakry airport.
8: The UN's health agency, the World Health Organization, says the Ebola outbreak is among the "most challenging" for health workers since the deadly disease emerged elsewhere in Africa four decades ago.
10: International aid organisations launch a series of emergency measures across west Africa in a bid to contain the outbreak.
15: Mali says it is clear of Ebola.
30: Guinea's Ebola outbreak is under control, but the death toll could rise above the current 74, President Alpha Conde says during a visit to Geneva.
26: Sierra Leone confirms its first death from Ebola and said it is restricting travel in some areas to stop the fever from claiming more lives.
18: Fresh data from the WHO confirms the outbreak to be the deadliest ever, with 337 deaths since January, a 60 percent increase in two weeks.
21: The WHO says the recent rapid spread of Ebola in the three countries has come in part because efforts to contain the deadly virus have been relaxed.
23: The outbreak is now "out of control" with more than 60 outbreak hotspots in Guinea, Liberia and Sierra Leone, the medical charity Doctors Without Borders says.
3: The WHO says at the close of a regional summit of health ministers on the crisis it expects the Ebola outbreak to continue for at least "several months".
25: The virus spreads to Africa's most populous country Nigeria, as a Liberian national dies in quarantine in Lagos. A day later the country places its ports and airports on alert.
27: A woman suffering from the first confirmed case of Ebola in Sierra Leone's capital, Freetown, dies.
29: After Nigeria's main airline Arik, pan-African airline ASKY suspends all flights to and from the capitals of Liberia and Sierra Leone.
30: Doctors Without Borders warns there is a risk of Ebola spreading to other countries.
Liberia announces it is shutting all schools and placing "non-essential" government workers on 30 days' leave.
31: Countries across the world announce stringent new security measures to contain the epidemic.
Sierra Leone declares a state of emergency.
The WHO raises the death toll by 57 to 729.