A Scottish nurse being treated at the Royal Free Hospital for a late complication of the Ebola virus is in a “serious condition”, the team treating her has said.

Pauline Cafferkey, who was successfully treated for the disease after being admitted to the hospital in Hampstead back in December, was flown from Glasgow to the Royal Free’s isolation unit after developing an “unusual late complication” of the infection.

She was transported in a military aircraft under supervision. People who have been in close contact with her are being monitored by Scottish health authorities as a precaution.

A statement, updated at midday, from the Royal Free said: “Pauline Cafferkey is in a serious condition.

“[She] was transferred from the Queen Elizabeth University Hospital in Glasgow to the Royal Free London hospital in the early hours of this morning due to an unusual late complication of her previous infection by the Ebola virus.

“She will now be treated in isolation in the hospital’s high-level isolation unit under nationally agreed guidelines.

“The Ebola virus can only be transmitted by direct contact with the blood or bodily fluids of an infected person while they are symptomatic, so the risk to the general public remains low and the NHS has well-established and practised infection control procedures in place.”

Ms Cafferkey was diagnosed with Ebola in December after returning to Glasgow from Sierra Leone, via London.

She spent almost a month in an isolation unit at the Royal Free Hospital at the beginning of the year.

Following her diagnosis, Ms Cafferkey received an experimental anti-viral drug and blood from survivors of the Ebola disease.

She was in a critical condition for two weeks and was discharged from the Royal Free in late January.

She admitted afterwards that she had felt like “giving up” as her condition became critical.

The disease has no known cure and is unpredictable.

Dr Ben Neuman, lecturer in virology at the University of Reading, said he thought Ms Cafferkey’s case was only the second one where Ebola is reported to have “reactivated”.

He said: “The newly-discovered twist on this post-Ebola syndrome is that, in some cases, the health problems - often including damage to the eyes and joints - is actually caused by live Ebola virus growing in bodily fluids in some of the less accessible compartments of the body.

“Ebola can persist for weeks or even months in breastmilk, semen and the fluid inside the eyeball.

“This is only the second case of reactivated Ebola, the other being the survivor whose eye changed from blue to green due to an ongoing infection.

“It is difficult to be certain of the outcome at this stage. The likelihood of spreading Ebola depends on how much of the virus is present in the blood. If her body was able to control the virus once, chances are she can do it twice.”

The most recent outbreak of Ebola mainly affected three countries in West Africa: Guinea, Liberia and Sierra Leone.

More than 28,000 cases and more than 11,000 deaths have been reported by the World Health Organisation.

A statement from NHS Greater Glasgow and Clyde said Ms Cafferkey was admitted to the Queen Elizabeth University Hospital in Glasgow on Tuesday after feeling unwell.

During this time she was treated in the infectious diseases unit, it said.

Ms Cafferkey, who is from South Lanarkshire, won an award at the the Pride of Britain Awards in central London on September 28.