The number of Ebola cases has risen more this week than any other week since the epidemic began, health officials have warned.
The World Health Organisation labelled the latest figures as a clear sign the outbreak is spiralling out of control, saying it was an "international health emergency".
A new mobile laboratory has opened this week in Sierra Leone's capital city Freetown to test local cases, with the aim of speeding up the response time.
It has also unveiled a £296 million ($490m) plan to try to contain the epidemic.
More than 160 staff will work in a UK-funded facility in Sierra Leone which is due to open in October.
UK trials of a vaccine for the Ebola virus began today - but some experts complain that the response has been a long time coming.
A Swansea doctor who took leave to treat Ebola patients in Africa, is back on the wards after three weeks in isolation.