An undated Cafferkey family handout photo of Scottish nurse Pauline Cafferkey. Cafferkey was working at a Save the Children specialist ebola hospital in Sierra Leone in November 2014. (Ho/EPA)

A British nurse being treated for Ebola in London is in critical condition after deteriorating over the past two days, hospital officials said Saturday.

Pauline Cafferkey, 39, is being treated at the Royal Free Hospital with blood plasma from an Ebola survivor and an experimental anti-viral drug. She was diagnosed with Ebola on Monday after returning to Britain late Sunday from Sierra Leone, where she had been working at a treatment center outside the capital, Freetown.

Royal Free Hospital successfully treated aid worker William Pooley with the experimental drug ZMapp in August. The hospital did not say which drug Cafferkey is being treated with, but it said no supplies of ZMapp were available.

Meanwhile, a South Korean medic exposed to Ebola while also working in Sierra Leone has been flown to Germany for treatment, authorities in Berlin said Saturday.

The Ebola epidemic over time

Frank Bergmann, who oversees the treatment of highly infectious patients at Charite hospital in Berlin, said the medic arrived in Berlin on Saturday, five days after suffering an injury with a hypodermic needle. He said the South Korean government and the medic had requested that as few details as possible be released, declining to give the person’s name, age, or employer.