Sierra Leone President Ernest Bai Koroma asked the country to begin a week of fasting and prayers on Thursday to end the Ebola virus that has killed more than 2 700 of his countrymen.

The worst outbreak on record of the virus is still spreading in West Africa, especially in Sierra Leone, and the number of known cases globally has exceeded 20 000, the World Health Organisation (WHO) said on Wednesday.

In a New Year's Day broadcast, Koroma said the seven days of prayers and fasting would begin immediately. “I ask all to commit our actions to the grace, mercy and protection of God Almighty," he said.

The death toll from the outbreak, which has been mostly confined to West Africa, has risen to 7 905, the WHO said, following 317 fatalities recorded since it last issued figures on the 24th of December. Sierra Leone is the worst-hit country in West Africa with more than 9 000 Ebola cases and the number of infections continue to grow.

It accounted for 337 of 476 new laboratory-confirmed cases since the 24th of December. Koroma also said schools which have been shut since July to curb the spread of the virus would reopen soon.

"The ministry of education is putting in place modalities to reopen schools and colleges in the shortest possible time,"Koroma said, without giving a specific date.

Many schools are being used as Ebola holding centres, raising questions as to how soon they will be able to reopen. Koroma urged people not to touch the sick or corpses and not to disobey quarantine orders.

"I know what we are being asked to do is very difficult; we are a people that have built our humanity on hugging each other, on shaking hands, on caring for the sick and showing communal empathy by participating in funeral activities but today the Ebola devil of illness and death hides in the innocent clothing of our culture to get us," he said.