Pauline Cafferkey
Pauline Cafferkey's condition has deteriorated recently hospital staff have reportedhandout

Save the Children have promised to "leave no stone unturned" to find out how a British nurse contracted the Ebola virus while volunteering in Sierra Leone.

Pauline Cafferkey was diagnosed with the disease upon returning to the UK after volunteering at the charity's Ebola treatment centre in Kerry Town in the west African country.

The Royal Free hospital, in north London, has said her condition has deteriorated over the past few days after undergoing treatment with an experimental antiviral drug.

The hospital insisted that there is "no danger" to staff or patients and remains open for business with in-patient, out-patient and emergency care continuing as normal while the 39-year-old is treated in an isolation unit.

The charity has now said they have launched an investigation into whether the Scottish public health nurse contracted the virus at their treatment centre or in the local community.

Save the Children's Rob MacGillivray told the BBC: "We have a review on at the moment. We are constantly reviewing our protocols and procedures to ensure staff working in Kerry Town centre take all measures possible to prevent themselves becoming infected with Ebola.

"And because of this very serious event we have put in an extraordinary review to ensure that we do everything, can leave no stone unturned to, as far as possible, identify the source of this infection.

"Everybody is exposed to a certain amount of risk working in Sierra Leone at the moment but we will certainly be focusing on how the personal protection equipment was used, how it was put on, and more importantly how it was taken off. The kinds of contact people have had perhaps in Kerry Town centre and perhaps outside so it will be a very full and thorough review."

MacGillivray said the review into how Cafferkey caught the disease will be published once completed and is "confident" in the protocols the charity had in place.

David Cameron added Ebola was the "uppermost thing" on his mind in the wake of Cafferkey's diagnosis.

He told BBC1's Andrew Marr Show: "It's certainly the thing uppermost in my mind today with Pauline Cafferkey in hospital, and all of us are thinking of her and her family.

"And also how incredibly brave these people are, not only doctors and nurses from our NHS but also people from our armed forces who have been working in west Africa in very difficult conditions."