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* Sierra Leone still records 248 new cases in past week
* More than 8,000 killed worldwide in epidemic to date
* WHO to host meeting on experimental vaccines on Thursday (Adds quotes from UN and WHO officials in Liberia)
By Stephanie Nebehay and James Harding Giahyue
GENEVA/MONROVIA, Jan 7 (Reuters) - Sierra Leone, the countryworst affected by Ebola, reported nearly 250 new confirmed casesin the past week but the spread of the virus there may beslowing, the World Health Organization said on Wednesday.
The epidemic has taken 8,235 lives out of 20,747 known cases worldwide over the past year, it said. Overall, 838 healthworkers have been infected, killing 495 of them.
The WHO's weekly report was based on figures reported byauthorities in nine countries. Guinea, Liberia and Sierra Leoneaccount for the majority of infections and fatalities.
"There are signs that case incidence may have levelled offin Sierra Leone, although with 248 new confirmed cases reportedin the week to 4 January 2015, it remains by far theworst-affected country at present," the WHO said.
Cases are still under-reported and unevenly spread in WestAfrica. The virus is spreading most rapidly in western SierraLeone, where the capital Freetown reported 93 of the newconfirmed cases, the WHO said.
"An increasing emphasis will be put on the rapid deploymentof smaller treatment facilities to ensure that capacity ismatched with demand in each area," the WHO said.
In Guinea, whose capital Conakry remains the worst-affecteddistrict, the western prefecture of Fria reported its firstEbola cases.
In Liberia, cases dropped from a peak of more than 300 newconfirmed cases per week in August and September to eight newconfirmed cases and 40 probable cases in the five days to Jan.2, it said.
Ismail Ould Cheikh Ahmed, the newly appointed head of theUnited Nations Ebola response mission known as UNMEER, warnedhowever against declaring a premature victory against thedisease during a visit to Liberia on Wednesday.
"It is only at this moment of optimism and relative successthat sometimes we are worried of a sense of complacency," hetold journalists.
Travelling with Ould Cheikh Ahmed, Bruce Aylward, the headof Ebola response at the WHO, echoed his concerns.
"There is still Ebola in Liberia and people are not actingthat way," he said. "There should be a ferocious attention todriving that number to zero and that concerns us a great deal."
On Thursday, the WHO will host a meeting of representativesfrom major drug makers, health authorities in affected countriesand national regulatory agencies to assess clinical trials ofexperimental vaccines against Ebola. GlaxoSmithKline,Merck, NewLink Genetics and Johnson & Johnson are testing experimental vaccines. (Editing by Angus MacSwan, Joe Bavier and James Dalgleish)
