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.
As it reaches seven months since the Ebola outbreak started we take a look at the timeline of events leading up to the spread of the virus.
More than 100 British personnel are arriving in Sierra Leone to combat the Ebola outbreak in West Africa. Here's what else the UK is doing.
A man has been filmed helping an Ebola patient onto a plane without wearing any protective equipment.