Ebola patient sitting up, reading and talking

Ms Cafferkey, 39, is also being given plasma donated by another patient who recovered from Ebola in Europe in the hope that it will help her battle the disease.

There are no licensed medicines proven to work against Ebola and the course of the illness is unpredictable, but her medical team have consulted experts internationally on the best approaches to take and will be monitoring Ms Cafferkey closely.

Dr Michael Jacobs, infectious diseases consultant at the Royal Free, said that Ms Cafferkey was not feeling well, but was still in the early phases of the illness and was as well as could be hoped for at this stage.

He revealed the nurse, who usually works at Blantyre Health Centre in Lanarkshire, had been sitting-up and talking inside the isolation tent. Dr Jacobs said: "She is able to read. She has been eating a bit, drinking and she's been in communication with her family which has been really nice."

Nursing staff are always with Ms Cafferkey, he said, family have visited and spoken to her through an internal communication system as well as by phone.

Dr Jacobs painted a picture of what the nurse has been through in the last week - flying back on Sunday from Sierra Leone where she had been "working incredibly hard" as a volunteer with Save the Children at an Ebola Treatment Centre. Then taking a late evening plane to Glasgow, becoming unwell and then being taken away from home again.

"I'm sure this isn't how she intended to spend New Year's Eve," said Dr Jacobs. "It has been a very unsettling time for her which she has coped with remarkably."

Noting her experience as a nurse, the clinician said staff had been able to have "really detailed" discussion with her about her treatment options and she was "realistic".

He did not disclose the name of the anti-viral drug which is being used, and said he wished he could be more confident it would work.

Patients who have recovered from Ebola after being treated in Europe have donated plasma and hospitals are collaborating across the continent to share this resource. The blood which Ms Cafferkey has received comes from one of these patients, although the individual concerned has not been identified.

Dr Jacobs said the treatment she has received so far has gone smoothly with no side-effects,.

The Royal Free Hospital has been unable to obtain ZMapp, the experimental drug they used to treat another Ebola patient William Pooley, because "there is none in the world at the moment".

Questions have been raised about the screening process which volunteers returning from Ebola hotspots in West Africa go through at Heathrow. Ms Cafferkey told officials at the airport she believed a fever might be developing, but her temperature was taken seven times and was normal each time, so she was allowed to fly on to Glasgow.

She was placed in an isolation unit at Gartnavel General after becoming feverish on Monday, and later flown to the Royal Free. Public health officials in Scotland have contacted all the passengers on the Heathrow to Glasgow flight, although the risk of Ebola being transmitted on the plane is considered extremely low.

There have been promises to review the screening system. Dr Aileen Keel, acting Chief Medical Officer for Scotland, said on the radio yesterday(wed) that she understood the correct protocols were followed, but added: "Now the issue of if she felt unwell and maybe shouldn't have travelled needs to be considered as part of our wider look at all of the issues around this case. Particularly the screening that's being conducted by Public Health England in London. And that will all be undertaken as part of our review of the case."