A nurse who apparently recovered from Ebola is now critically ill after the virus re-emerged, the BBC reported on 14 October. Pauline Cafferkey is back at the The Royal Free Hospital in London's specialist isolation unit where she was treated after contracting Ebola while working in Sierra Leone.

In January 2014 she spoke about the ordeal of being diagnosed and falling critically ill with Ebola after working in the west African country. Cafferkey, who had then been discharged from hospital after seemingly making a full recovery, was admitted to hospital after falling ill following her work with the charity Save the Children at a treatment centre outside the capital, Freetown. Experts have made it clear that there is an almost zero chance of others catching it.

"The risk of this virus spreading from her, either to people working in the unit, they're highly trained so they've got zero risk of catching it. But even to people who have been in contact with her, the risk will approach zero, so there's nothing to worry about for anyone who has been in contact with her in the last couple of weeks, there really is not," said Professor John Oxford of the University of London.

Talking about her apparent relapse. Ebola expert Dr Edward Wright of London's Westminster University, said; "We have no other documented evidence that anyone else who has survived infection has then had a relapse and the Ebola virus has started to cause disease again."

The Royal Free, Britain's main centre for Ebola cases, also successfully treated British aid worker William Pooley who also contracted the virus in West Africa.