An Italian doctor who contracted Ebola in November while working in Sierra Leone has been declared cured and been discharged from a Rome hospital.

Fabrizio Pulvirenti said at Spallanzani hospital on Friday that while he was gravely ill, he tried to mentally analyse his symptoms as a way to keep himself sharp.

The doctor, who worked with the Italy-based Emergency aid group, was given the same experimental drugs used in the US and other European countries to treat people infected with the virus, according to officials at the hospital.

Infographic: Just how deadly is Ebola?

Pulvirenti, in his 50s, was Italy's first Ebola patient. He said it was impossible to know when he contracted the virus.

After regaining full strength, Pulvirenti says he will consider returning to Sierra Leone.

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 December 24.

The disease has so far killed more than 2,700 in Sierra Leone so far.

President Ernest Bai Koroma asked the country to begin a week of fasting and prayers on Thursday to end the spread of the virus.

In a New Year's Day broadcast, Koroma said the seven days of prayers and fasting would begin immediately.

"Today I ask all to commit our actions to the grace, mercy and protection of God Almighty," he said.

Schools to reopen

In his remarks, Koroma 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," he 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," he said.

"But today the Ebola devil of illness and death hides in the innocent clothing of our culture to get us," he said.

The number of known Ebola cases globally has exceeded 20,000, the World Health Organisation said in its most recent figures released on Wednesday.

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.

Source: Agencies