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.
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.
The first British case of Ebola in the outbreak in West Africa has been confirmed. So how would repatriation work are what are the risks?