The previous toll released December 22 stood at 7,518 fatalities out of 19,340 infected in Sierra Leone, Liberia and Guinea.
Worldwide, the disease has killed at least 7,708, including six in Mali, one in the United States and eight in Nigeria, which was declared Ebola-free in October.
Spain and Senegal, which have both been declared free of Ebola, meanwhile counted one case each, but no deaths.
Sierra Leone, which has overtaken Liberia as the country with the most infections, counted 9,203 cases and 2,655 deaths on December 24, the WHO said.
Four days earlier the toll stood at 8,939 cases and 2,556 deaths.
Liberia, long the hardest-hit country, has seen a clear decrease in transmission over the past month.
As of December 20 the country counted 7,862 cases and 3,384 deaths, up from 7,830 cases and 3,376 deaths recorded in the previous update, the WHO said.
In Guinea, where the outbreak started a year ago, 2,630 Ebola cases and 1,654 deaths were recorded as of December 24.
The previous tally showed the country with 2,571 Ebola cases and 1,586 deaths.
Ebola, one of the deadliest viruses known to man, is spread only through direct contact with the bodily fluids of an infected person showing symptoms such as fever or vomiting.
People caring for the sick or handling the bodies of people infected Ebola are especially exposed.
As of December 21 a total of 666 healthcare workers were known to have contracted the virus, and 366 of them had died, according to WHO. – AFP