A Scottish nurse who contracted Ebola in Sierra Leone last year is in a "serious condition" after being readmitted to an isolation unit in London.
British health authorities have confirmed that Pauline Cafferkey still has the Ebola virus left over from the original infection, and it is monitoring dozens of people she has had contact with.
Dr Janet Scott from the University of Liverpool said the nurse's case was not that unusual as she had seen people at a Sierra Leone Ebola survivors' clinic with lingering symptoms.
NHS Greater Glasgow and Clyde confirmed that the virus is still present in Pauline Cafferkey's body after being left over from the original infection.
She is not thought to be contagious.
The 39-year-old has been flown back to the isolation unit at the Royal Free Hospital in London.
Bodily tissues can harbour the Ebola infection months after the person appears to have fully recovered.
Ms Cafferkey, from Cambuslang in South Lanarkshire, spent almost a month in the unit at the beginning of the year after contracting the virus in December 2014.