Story highlights Guinea, Liberia and Sierra Leone had 99 new cases for week ending January 25

It's the first time the number has fallen below 100 in a week since late June

(CNN) The number of new Ebola cases reported in the three worst-hit countries fell to its lowest level since late June, the World Health Organization said Thursday.

Guinea, Liberia and Sierra Leone had a combined total of 99 new cases for the week ending January 25, the WHO said.

The total breaks down to 65 in Sierra Leone, 30 in Guinea and four in Liberia.

The number of cases continued to fall in Liberia and Sierra Leone, WHO said, but Guinea's figure rose from 20 confirmed cases in the previous week.

The western district of Forecariah -- where the local community has shown high levels of resistance to measures to limit the disease's spread -- was the worst-affected in Guinea, with half the new cases for the week, the report said.

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