A health official works at the Ebola treatment centre run by the French red cross society in Macenta

A woman is thought to have died from Ebola in Sierra Leone, a government spokesman said Thursday, hours after the World Health Organization declared an end to an epidemic of the disease.

"A high level team of Ministry of Health officials and key partners including the World Health Organization and the Atlanta-based Centre for Disease Control are in the area from the capital to undertake intensive investigations," Abdulai Bayrayta told AFP.