FREETOWN, Sierra Leone -- Authorities in Sierra Leone said Sunday that another doctor there has tested positive for Ebola, marking a setback for efforts to keep desperately needed health care workers safe in the West African country ravaged by the deadly virus.

A child stands near a sign advising of a quarantined home in an effort to combat the spread of the Ebola virus in Port Loko, Sierra Leone, Wednesday, Oct. 22, 2014. (AP / Michael Duff, File)

Government Chief Medical Officer Dr. Brima Kargbo confirmed on Sunday that a fifth doctor in Sierra Leone had tested positive. The other four all have died from the virus that has killed nearly 5,000 across West Africa.

The sick physician has been identified as Dr. Godfrey George, medical superintendent of Kambia Government Hospital in northern Sierra Leone. He was driven to the capital, Freetown, after reporting he wasn't feeling well.

France said it was treating a UN employee who had contracted Ebola while working in Sierra Leone.The unidentified UN employee had been evacuated by a special flight and was undergoing treatment in "high-security isolation" in the Begin Army Training Hospital in Saint-Mande, near Paris.