A nurse who survived Ebola is recovering well after the deadly virus caused her to develop meningitis in what is thought to be the first case of its kind, doctors have said.
Pauline Cafferkey, 39, was re-admitted to the isolation unit at the Royal Free Hospital in north west London on October 9, months after she was thought to have fought off the Ebola infection.
She was previously described as "critically ill" but has now shown "significant improvement" after being treated with the experimental drug GS5734, which is being tested on humans.
Dr Michael Jacobs from the Royal Free Hospital described the situation as "unprecedented", while the World Health Organisation said Ms Cafferkey was the only known Ebola survivor to develop meningitis months later.
Dr Jacobs, infectious diseases consultant at the hospital, told a press conference: "This is the original Ebola virus she had many months ago which has been inside the brain, replicating at a very low level, and has now re-emerged to cause this clinical illness of meningitis.
"This is an unprecedented situation.
"The last few days she has made a significant improvement.
"This is a highly experimental treatment. We don't know if it's of benefit to her."
Dr Jacobs said it was a "completely different" type of Ebola than had been seen by medical staff previously.
"It's really important to understand we don't use the term critically ill lightly," he said.
"It means someone is at imminent risk of dying. We were extremely concerned about Pauline's condition.
"That's why we're thrilled to be having this press conference."
Dr Jacobs said the patient remained in an isolation unit but was able to talk to hospital staff and use an iPad.
"I think she has a long recovery ahead of her," he added.
"She will be with us at the Royal Free Hospital for quite a while still."
Dr Jacobs said it was still unclear whether people who were in contact with Ms Cafferkey's bodily fluids had been exposed to Ebola.
He told reporters: "This is a situation we didn't expect to face and is new to us.
"We're unable to rule out the fact that people who had intimate contact with some of her body fluids for whatever reason, there may have been a risk they could have been infected with Ebola."
Ms Cafferkey, who is from South Lanarkshire, first contracted Ebola while working as a nurse at the Save the Children treatment centre in Kerry Town, Sierra Leone.
She was diagnosed in December after returning to Glasgow from the west African country via London.
She spent almost a month in an isolation unit at the Royal Free before being discharged in late January. Ms Cafferkey's family have previously claimed doctors "missed a big opportunity" to spot she had fallen ill with Ebola again.
A total of 58 close contacts of the nurse have been identified, with 40 of those offered vaccinations as a precaution.