Ebola: How 'spikes' in virus are controlled in Sierra Leone
Some areas in Sierra Leone have managed to curb the spread of the Ebola virus, according to the World Health Organization.
Winnie Romeril, speaking in Freetown, said a push to identify at-risk areas had been an important factor in gaining control.
A government initiative has persuaded those communities to bring sick people to hospitals, and to bury their dead safely.
But some areas, such as Freetown and its surrounding areas, remain difficult to tackle, as Ms Romeril told the BBC's Tulip Mazumdar.