"There are now 109 suspected cases of which 42 are confirmed," said a statement from the health ministry, adding that six more people had been killed by the tropical pathogen since a death toll of six was announced a week ago.
Two of the new deaths were health workers in Kailahun, an eastern district near the border with Guinea, the epicentre of the west African outbreak which has killed more than 200 people since the beginning of January.
Sierra Leonean media reported that panicked health workers were abandoning their posts in the area, although AFP was not immediately able to confirm the information.
The impoverished west African nation confirmed its first deaths from Ebola, one of the deadliest viruses known to man, two weeks ago.
The tropical bug can fell its victims within days, causing severe fever, muscle pain, weakness, vomiting and diarrhoea -- and in some cases shutting down organs and causing unstoppable bleeding.
No medicine or vaccine exists for Ebola, which is named after a small river in the Democratic Republic of Congo.
The UN's health agency said on Wednesday last week it had so far registered 328 confirmed or suspected cases of Ebola in Guinea, including 208 deaths, with 21 deaths registered between May 29 and June 1 alone.
The virus appears to have resurfaced in neighbouring Liberia, which earlier this year had seen 12 suspected and confirmed cases of Ebola, including nine deaths, but had not seen any new cases for nearly two months.
A person believed to have been infected in Kailahun came across the border and died in Foya, WHO said, pointing out that the dead body was taken back into Sierra Leone to be buried.