Though the battle against Ebola is far from over, Liberia has set target to halt the disease by the end of the year.
World Bank President Jim Yong Kim warned Friday that despite gains against the deadly epidemic the new outbreak in Mali was "very worrisome".
"We must get to zero cases. Ebola is not a disease where you can leave a few cases and say you've done enough," he said at a summit on the epidemic with the leaders of the United Nations, World Health Organization and the International Monetary Fund.
The head of the UN Ebola mission warned that the world was "far, far away" from beating the deadly outbreak and said a huge increase in aid was needed to fight the virus in Africa.
"There is a long battle ahead of us," Anthony Banbury told the UN Security Council, which met two months after it declared the outbreak a threat to world security.
After the death on Monday of a Sierra Leonean doctor evacuated to the United States, a member of the Cuban medical contingent in Sierra Leone tested positive and was transferred Thursday to Geneva.
A Spanish Doctors Without Borders volunteer, who injured himself while treating an Ebola patient in Mali, was repatriated as a precaution on Friday.
The outbreak -- by far the worst on record of the tropical fever, which emerged almost a year ago in southern Guinea -- has killed around 5,500 out of 15,351 cases according to the World Health Organization (WHO).
- Wake-up call -
Experts acknowledge that real toll of infections and deaths could be up to three times higher than the official figures.
More than 99 percent of cases and deaths are concentrated in three countries.
The WHO says the epidemic in Guinea and Liberia "is due to intense transmission in some key provinces" while transmission is "intense throughout northern and western Sierra Leone".
UNICEF said on Friday it was stepping up efforts to help other west African countries at risk prepare for potential outbreaks, given "new Ebola cases in Mali and a continuing surge in Sierra Leone".
"The new cases in Mali remind us that no country in the region is immune to Ebola," regional director Manuel Fontaine said in a statement.
Mali, the newest country to be caught up in the epidemic, recorded its seventh Ebola death on Thursday.
The contagion entered the country in October when a two-year-old girl who had entered from Guinea died in the western town of Kayes, without spreading the virus any further.
Three weeks later an Islamic cleric, also from Guinea, died the capital Bamako, transmitting the virus, directly or indirectly, to at least five people, all of whom are now also dead.
More than 300 people are under surveillance as a result of that chain of transmission, including two new suspected cases currently undergoing tests, according to Mali's health ministry.
Nelson Mandela's widow Graca Machel Friday said the Ebola epidemic should be a wake-up call for African leaders, saying it had exposed the "extreme weakness" of African institutions.
- 'Not out of woods' -
After months of delays, personnel and aid are flowing into the region from across the world.
A first group of 30 volunteers from Britain's state National Health Service were to depart Saturday for Sierra Leone where they will work on British-built treatment centres around the west African country.
Liberia -- host to 2,200 United States troops and, since a week ago, 160 Chinese military doctors -- has had much reason for optimism, reporting a sharp decline in new cases in recent weeks.
President Ellen Johnson Sirleaf has tentatively welcomed the gains, banging the drum of a "national goal of zero new cases by Christmas" whenever the occasion fits.
In a sign of life returning to normal, the election commission announced on Thursday the launch of the campaign for nationwide senatorial polls, set for December 16 after a delay of two months.
The "Karel Doorman", a Dutch vessel loaded with 160 vehicles, a mobile lab and more than 1,000 tonnes of medical equipment from nine European countries, arrived on Friday in Conakry.
It was in Freetown on Thursday and concludes its mission in Monrovia on Saturday.
French President Francois Hollande said on Friday he would travel next week to Conakry, where his country is at the forefront of the fight against Ebola, and confirmed a team of four experts had been sent to Mali.
President Barack Obama hailed the "real impact" of US efforts in Liberia on Tuesday but warned that the fight to stem the contagion was far from over.
"As long as the outbreak continues to rage in the three countries in west Africa -- Liberia, Sierra Leone and Guinea -- this is still going to be a danger, not just for America, but for the entire world," he said before meeting with his Ebola response team.
"We are nowhere near out of the woods yet in west Africa."
The US is offering a temporary haven to citizens from the three countries, protecting them from deportation back home.