Here is a timeline of the return of nurse Pauline Cafferkey to the UK and her subsequent diagnosis of Ebola.
Mrs Cafferkey arrives at Heathrow Airport after travelling from Sierra Leone via Casablanca in Morocco.
As a returning health worker she is screened and has her temperature taken at the airport but no concerns are raised.
While waiting for a connecting flight to Glasgow she complains about her temperature and has it checked a further six times but is given the all clear to fly.
She arrives at Glasgow airport at 11.30pm and takes a taxi home.
The health worker raises the alarm that she is feeling unwell and is admitted to the specialist Brownlee Unit for Infectious Diseases on the Gartnavel Hospital campus, Glasgow, where she is put in isolation at 7.50am.
Health officials begin tracing other passengers on board the flight with Mrs Cafferkey.
Mrs Cafferkey is flown to specialist facilities at the Royal Free Hospital in north London on an RAF C-130 Hercules plane. She is later described as "doing as well as can be expected".
First Minister Nicola Sturgeon says the risk to the general public is "extremely low to the point of negligible".
Chief medical officer Professor Dame Sally Davies said the experimental drug ZMapp, which was used to treat survivor Will Pooley, the first UK citizen to contract the disease, is "not available at the moment".
She adds that "questions have been raised" over airport screening procedures for Ebola.
Mrs Cafferkey's doctor, Dr Michael Jacobs, reveals she is being treated with convalescent plasma taken from the blood of a recovered patient and an experimental anti-viral drug which is "not proven to work".
He says she is sitting up, reading, eating a little and communicating with her family.
But he warns that the next few days will be "critical".
Public Health England confirms that all UK-based passengers and crew aboard the flights between Morocco and Heathrow and Heathrow and Glasgow taken by the nurse have been contacted and issued with advice on what to do if they feel unwell.
The Royal Free Hospital releases a statement saying that the condition of Mrs Cafferkey has deteriorated over the past two days and is now critical.