A lab technician in the US has been placed under observation for possible exposure to the deadly Ebola virus.
The employee at the Centers for Disease Control and Prevention in Atlanta is being monitored after a sample was mistakenly moved from one laboratory to another.
The worker will be monitored for 21 days and the person's name hasn't been released.
The WHO says 6,055 people have died in Liberia, Sierra Leone and Guinea.
It was revealed earlier this month that a WHO deadline to halt the outbreak was only met by Guinea.
In October, the organisation launched its plan to isolate 70% of those infected and safely bury 70% of the victims in Guinea, Liberia and Sierra Leone by December 1st.
But in Liberia, only 23% of cases are isolated and 26% of the needed burial teams are in place.
In Sierra Leone, around 40% of cases are isolated and 27% of burial teams are operational.
The Ebola outbreak was first reported in Guinea in March, and has spiralled out of control since a public health emergency was declared in August.
