The Ebola virus is still spreading in West Africa, especially in Sierra Leone, and the number of known cases globally has now exceeded 20,000, the World Health Organization said on Wednesday.

The death toll from the outbreak, which has been mostly confined to West Africa, has risen to 7,905, the WHO said, following 317 fatalities recorded since it last issued figures on Dec. 24.

The number of known cases, including fatalities, totalled 20,206 at year-end, it said.