Some 729 people have died from the outbreak of Ebola, the World Health Organisation (WHO) has said.
Fifty-seven deaths were reported between July 24 and 27 in Guinea, Liberia, Nigeria and Sierra Leone.
The news comes after Liberia's ambassador to the US warned that the crisis was "escalating by the hour".
Nigeria has also identified 59 people who came into contact with a man who died in Lagos last week after travelling from Liberia, WHO said.
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.