The death toll from Ebola in the three West Africa countries hardest hit by the epidemic has risen to 7,573 out of 19,463 confirmed cases recorded there to date, the World Health Organization (WHO) said on Wednesday.

Sierra Leone has the most cases, 9,004, while Liberia has the highest death toll, 3,384, according to its latest figures. Guinea, where the outbreak began a year ago, is the third hardest-hit.

The Ebola crisis that claimed its first victim exactly a year ago is likely to last until the end of 2015, according to Peter Piot, a scientist who helped to discover the virus in 1976