A body has tested positive for Ebola in Sierra Leone, a spokesman for the Health Ministry said, just hours after the World Health Organization said transmission of the virus in West Africa had ended, according to Reuters.

Two swab tests carried out on the deceased person by British health organisation Public Health England came back positive in the north of the country, the spokesman said late on Thursday.

Neither the gender nor age of the deceased was released.

The tests reinforce concerns about flare-ups of the virus that has killed more than 11,300 people since 2013, almost all of which were in Sierra Leone, Guinea and Liberia.

Sierra Leone had been declared free of the virus on Nov. 7.

The World Health Organisation warned on Thursday that despite there being no known transmissions of the disease in over two months, there could still cases of the disease in the region, which has suffered the world's deadliest outbreak over the past two years, as survivors can carry the virus for months and can pass it on.