Scotland's First Minister has hailed the "quiet heroism" of a British nurse who is critically ill with Ebola as she warned the UK is likely to experience more cases of the deadly disease.

Nicola Sturgeon said there could be "a small number of additional cases" of Ebola.

She made the comments in a statement to MSPs at Holyrood about the case of Scottish nurse Pauline Cafferkey, 39, who was diagnosed with the virus after returning from voluntary work in Sierra Leone.

Ms Cafferkey is currently being treated in isolation at the Royal Free Hospital in north London, where her condition "remains critical", the First Minister said.

Ms Sturgeon said: "By far the most effective way of reducing the risk of Ebola in Scotland, and indeed in the rest of the UK, is to halt its spread in west Africa.

"It is why we are so deeply grateful for the quiet heroism of Pauline Cafferkey and many others like her, from Scotland, the rest of the UK and from many other countries, who make all of us safer by placing themselves at risk.

"They are not simply helping people in west Africa, although they are certainly doing that, they are also helping people right around the world.

"We owe it to them, as well as to the wider public, to ensure that the measures we are taking to tackle Ebola here in Scotland are as good as they can be."

Officials from both Public Health England and Health Protection Scotland are currently reviewing the UK's screening procedures for Ebola, after it emerged Ms Cafferkey had been cleared to fly from London to Glasgow despite her temperature being checked seven times after she landed at Heathrow.

The nurse was admitted to an isolation facility at the Brownlee unit in Gartnavel Hospital, Glasgow, at 8am on December 29.

After a blood sample tested positive for Ebola, she was transferred by military plane to the Royal Free Hospital early the following morning.

With more health workers due to return to the UK from Sierra Leone in the next two weeks, Ms Sturgeon pledged: "We will keep all of the procedures under review. It is important that we learn lessons from the case of Pauline Cafferkey and that we learn lessons from any other case that might arise.

"I hope there are no other cases identified in Scotland or the UK but it is likely we will see other cases, a small number of additional cases, and we need to keep learning from the experience of dealing with them."

Ms Cafferkey had been working with the charity Save the Children at the Ebola Treatment Centre in Kerry Town, Sierra Leone, before she became ill.

Ms Sturgeon said questions had "understandably" been asked about the procedures in place after the nurse was allowed to fly from London to Scotland.

She told Holyrood that protocols at airports have "already been revised" in light of the case.

The First Minister said: "The guidance has been strengthened to ensure that anyone from a higher risk group who feels unwell will be reassessed.

"Advice will also be sought immediately from an infectious diseases specialist and the passenger referred on for testing if appropriate."

Ms Cafferkey's temperature was "within the acceptable range" each time she was tested, Ms Sturgeon said.

"Because she was not at the point displaying any symptoms that would have given rise to onward transmission, the risk to other passengers on her flights was extremely low."

Ms Sturgeon assured MSPs that all health boards in Scotland have "appropriate plans and equipment in place" to deal with suspected Ebola cases.

Regional units for the management of any possible or confirmed cases have been established in Glasgow, Edinburgh and Aberdeen, with these having more than 50 isolation rooms in total, Ms Sturgeon said.

She added: "Patients who require high-level isolation will go to the Royal Free. The Royal Free is a very specialist facility.

"In the United States of America, which has a population of 300 million people, there are only four units of the same type as the Royal Free, that's how specialist these units are.

"Many other European countries don't have facilities of the standard of the Royal Free, so it is absolutely right that where patients need that treatment, that is what they get."

She stressed: "NHS Scotland, of course, pays for any treatment in the Royal Free of Scottish patients."

Opposition leaders at Holyrood also paid tribute to Ms Cafferkey, with Scottish Labour deputy leader Kezia Dugdale describing her bravery as "extraordinary".

Ms Dugdale said: "Hero is a word we use too readily and in so doing we diminish its value.

"The definition of a hero is someone who risks their own life for others, someone who puts themselves in danger for the benefit of others.

"Pauline Cafferkey is a hero, as are all of the aid workers helping to fight Ebola, heroes whose names we will never know."

Scottish Conservative health spokesman Jackson Carlaw said the nurse is "deserving of nothing less than the support, love and affection of everyone in this chamber, Scotland and the wider United Kingdom".

Mr Carlaw praised Ms Cafferkey, saying: "She and all those like her who selflessly put themselves in the face of great hazard in the service of others really deserve our total support.

"We all wish her well in the fight she now has back to greater health."

Meanwhile, a special NHS 24 helpline that was set up within hours of Ms Cafferkey being diagnosed with Ebola is being shut down from this evening, Ms Sturgeon announced.

It has taken a total of 179 calls, but only three of these have been received since December 31, MSPs were told.

While it is being closed down at 6pm, Ms Sturgeon stressed it could be "reactivated quickly should the need arise".