The man, who was working at the IFRC Ebola treatment centre in Kenema, “passed away on 13 January 2015 and was confirmed positive for Ebola virus disease later that day”, the International Federation of Red Cross and Red Crescent Societies (IFRC) said in a statement.
The Red Cross said it was carrying out an investigation to determine how and where he became infected, and 29 people who had contact with him were being monitored for symptoms of the disease.
District medical officer Mohamed Vandy said “the family and co-workers of the deceased are now quarantined for 21 days”, the maximum incubation period for the virus.
Prior to the nurse’s death, Kenema district had been free of new cases of Ebola for 37 days, health ministry spokesman Abass Mamara told AFP.
“There were no cases reported from December 6, 2014 until Monday, January 12,” he said.
In the neighbouring district of Kailahun, no new cases had been reported for at least 34 days, according to Doctors Without Borders (MSF), which is leading the fight against Ebola in West Africa.
Kenema and Kailahun have been under quarantine since August. The Eastern Province, which includes both districts, was the first epicentre of the epidemic in the country.
Sierra Leone and neighbouring Liberia and Guinea are the three west African countries most affected by the epidemic.
They account for 99 percent of the estimated 8,500 Ebola deaths from more than 21,000 cases reported since December 2013, according to the latest World Health Organization report- AFP