The UN health organisation said that between last Thursday and Saturday there were 84 more deaths and 113 new infections in the four countries affected by the epidemic - Guinea, Liberia, Sierra Leone and Nigeria.
The outbreak began in Guinea in the first quarter of 2014 and rapidly spread to neighbouring countries like Liberia, where the escape two days ago of patients with Ebola from a Monrovia quarantine centre, which was attacked, has raised new fears of contagion.
Health officials in Liberia have expressed concern about the rapid pace of the epidemic in the three days running between last Thursday and Saturday, in which 53 more deaths and 48 new cases were reported.
Liberia is already the worst-hit country with 466 deaths and 834 infections, while in Guinea there have been 394 deaths and 543 cases.
In Sierra Leone, the cases jumped to 848 with 365 deaths, while Nigeria, where the virus seems to have been contained, has registered 15 cases and four deaths.