A nurse who contracted Ebola in Sierra Leone is in a "serious condition", according to medics at the hospital where she is being treated

Pauline Cafferkey has been flown from Glasgow to an isolation unit at the Royal Free Hospital in Hampstead, north-west London.

Glasgow Times:

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.

Glasgow Times:

A statement from the Royal Free said: "We can confirm that Pauline Cafferkey 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."

Professor Paul Cosford, medical director at Public Health England (PHE), said: "She was transported in a military aircraft under the supervision of experts.

"The Scottish health authorities will be following up on a small number of close contacts of Pauline's as a precaution."

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.

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.

Director of public health Dr Emilia Crighton said: "Pauline's condition is a complication of previous infection with the Ebola virus.

"The risk to the public is very low. In line with normal procedures in cases such as this, we have identified a small number of close contacts of Pauline's that we will be following up as a precaution."

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

She met the Prime Minister's wife Samantha Cameron the following day at Downing Street, alongside other winners.

The Daily Mirror awards recognise courage and achievement against the odds, with nominees voted by members of the public.

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.

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.

After becoming infected, it emerged that Ms Cafferkey's temperature had been tested seven times before she flew from Heathrow to Glasgow in December.

She was cleared to travel but later became seriously ill.

She was placed in an isolation unit at Glasgow's Gartnavel Hospital after becoming feverish, before being transferred by an RAF Hercules plane to London on December 30.

She was then transferred to the specialist isolation unit at the Royal Free.

First Minister Nicola Sturgeon wished her a speedy recovery tweeting:

Scotland’s Chief Medical Officer Catherine Calderwood said: “We are aware that Pauline Cafferkey has been transferred from the Queen Elizabeth University Hospital to the Royal Free Hospital in London as a result of becoming unwell from an unusual late complication of her illness.

"We have been working closely with NHS Greater Glasgow & Clyde and Health Protection Scotland to ensure Pauline has received all appropriate treatment and care throughout her stay at the QEUH and onward transfer to the Royal Free Hospital.

“Pauline is now being cared for in the best place possible, with specialists who have the most experience of looking after patients who have previously recovered from the ebola virus. This is not a new case of ebola and is a complication of her previous illness.

"The risk to the public remains extremely low and all appropriate infection control measures are in place.”

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."

Meanwhile, the Royal Free Hospital in north-west London has the UK's only high-level isolation unit for infectious diseases.

Access to the unit is restricted to a team of medical staff specifically trained in handling extremely contagious viruses.

It can be up and running to admit a patient at very short notice.

A specially-designed tent with controlled ventilation is set up around the patient's bed. It allows staff to provide care to the patient while preventing spread of the infection.

The unit also has one specific entrance for the patient, pressure chambers to decontaminate waste, and a dedicated laboratory for carrying out tests.

All the air leaving the unit goes through special filters to clean it so there is no risk to anyone else at the hospital.

A dedicated team of doctors, nurses and laboratory staff run the unit.

Glasgow Times: Rapid test kit for Ebola being made in Dundee

Here are some facts about the Ebola virus:

What is Ebola?

Ebola is one of the world's deadliest diseases, with more than 50% of cases resulting in death. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. Outbreaks mainly occur in remote villages in Central and West Africa. Fruit bats of the Pteropodidae family are believed to be the natural host of the virus. The disease was first recorded in two simultaneous outbreaks in 1976 near the Ebola River in the Democratic Republic of Congo.

How did the latest outbreak occur?

The first cases of the current outbreak in West Africa were detected in March 2014. It is the largest and most complex Ebola outbreak since the Ebola virus was first discovered. The most severely affected countries are Guinea, Liberia and Sierra Leone, where weak health systems and recent instability have contributed to the spread of the virus. The World Health Organisation declared the West Africa outbreak a Public Health Emergency of International Concern. For those living outside West Africa the threat level remains very low.

What are symptoms?

The symptoms of Ebola are severe, with patients often overcome by a sudden onset of fever as well as weakness, muscle pain and headaches. Vomiting, diarrhoea, rashes, kidney and liver problems follow as the virus grips the body. The incubation period - the time between infection and the onset of symptoms - ranges from two days to three weeks.

How is it spread?

Ebola spreads from person to person as a result of direct contact with the blood, organs or other bodily fluids of those infected, with healthcare workers among those most at risk. However, it is only contagious while an infected person is suffering from symptoms.

How is it treated?

Patients diagnosed with Ebola are placed in isolation in intensive care, where their blood oxygen levels and blood pressure are maintained at the right level and their body organs supported.

Who has died?

As of October 4 2015, 11,312 people have died globally after contracting Ebola, Public Health England said. This includes a number of tourists and travellers in Europe and America after returning from West Africa. For the first time last week, no new cases of Ebola were reported, the World Health Organisation said.

Who has been affected in the UK?

Nurse Will Pooley, from Suffolk, last year became the first Briton to contract Ebola while working out in Sierra Leone. Following his recovery he returned to the country to continue helping treat patients. Nurse Pauline Cafferkey was later diagnosed with the illness after returning from healthcare work in West Africa. British Army medic Anna Cross, 25, recovered from the disease after being treated with an experimental drug. All three were treated at the high-level isolation ward at the Royal Free Hospital in London.

How has the UK Government reacted?

The UK committed £427 million of direct support to help control and treat Ebola, including setting up six Ebola treatment centres in Sierra Leone. Hundreds of NHS staff volunteered to travel to West Africa and help those affected by Ebola while UK military personnel ran the UK-led Ebola Training Academy in Freetown.

Screening for Ebola was put in place at the UK's main ports of entry for people travelling from West Africa during the peak of the outbreak.

Is there a vaccine?

There is currently no licensed treatment or vaccine for Ebola virus disease, although potential new vaccines and drug therapies are being developed and tested. Both MIL 77 and ZMapp are experimental treatments which have been used to treat patients.