The Ebola epidemic has infected 10,000 people, according to figures from the World Health Organisation, and the outbreak is showing no signs of stopping its spread
Of those cases, 4,922 people have died of the virus, which causes internal bleeding and high fever.
The Ebola epidemic in West Africa is the largest ever outbreak of the disease with a rapidly rising death toll in Guinea, Liberia and Sierra Leone. There have also been cases in three other West African countries, Spain and the United States.
The UN health agency said calculated the total number of infections is now 10,141. Its figures show about 200 new cases since the last report, four days ago.
Even those grisly tolls are likely an underestimate, WHO has warned, as many people in the hardest hit countries have been unable or too frightened to seek medical care. A shortage of labs capable of handling potentially infected blood samples has also made it difficult to track the outbreak.
For example, the latest numbers show no change in Liberia's case toll, suggesting the numbers may be lagging behind reality.
On Thursday, authorities confirmed that the disease had spread to Mali, the sixth West African country affected, and on the same day a new case was confirmed in New York, in a doctor recently returned from Guinea.
Mali had long been considered highly vulnerable to the disease, since it shares a border with Guinea. The disease arrived there in a 2-year-old, who traveled from Guinea with her grandmother by bus and died Friday.
The toddler, who was bleeding from her nose during the journey, may have had high-risk contact with many people, the WHO warned. So far, 43 people are being monitored in isolation for signs of the disease, and WHO said Saturday that authorities are continuing to look for more people at risk.
To help fight Ebola, the UN humanitarian flight service airlifted about a ton of medical supplies to Mali late Friday. The seats of the plane were removed to make room for the cargo, which included hazard suits for health workers, surgical gloves, face shields and buckets, according to the World Food Program, which runs the flights.
"Speed is of the essence in this Ebola crisis. Agencies such as WFP and WHO are working every hour to confront together the virus as a matter of priority," said Denise Brown, the West Africa regional director for the UN food agency.
European Union leaders have pledged a total of 1 billion euros (£789 million) to help fight the outbreak of the killer disease in west Africa.
The promises, at a European Council summit in Brussels on Friday, came after David Cameron threw down the gauntlet to fellow leaders in a letter last week, in which he warned them that failure to halt the virus at source would put Europe at risk.
The Prime Minister - who earlier in the week announced an additional £80 million in UK funding, bringing the total British contribution to £205 million - welcomed the agreement.
"Over a billion euros across Europe will be galvanised and spent on dealing with this issue," he said. "I have been absolutely determined that Britain with other countries will lead the way in dealing with this.
"Dealing with this because there is a massive crisis in west Africa and we should feel some moral obligation as a wealthy country to help but also dealing with it because it directly threatens our national interest and our people in the United Kingdom."
Britain has taken a leading role in tackling the epidemic in former colony Sierra Leone, while the US leads the international effort in neighbouring Liberia and France in Guinea.
Until the new announcement, the UK effort dwarfed those of most of its EU partners in terms of both cash and manpower - totalling more than the contributions of another 19 countries combined.
Ahead of this week's summit, furniture store Ikea had outspent 18 EU member-states - including Ireland, Spain, Luxembourg and Poland - in support for the Ebola effort, with a donation of five million euros (£4 million).
Cameron warned that the virus could spread to Europe if it was not stopped in its tracks in the African states where the deadly outbreak began earlier this year.
"It is very important we take action at source in west Africa," said the Prime Minister. "Britain has been leading the way in terms of Sierra Leone and we have already pledged £125 million, we have got military and other forces going to that country to help. But we need other countries to do more."
A UK source suggested that the slowness of some European states to respond to the emergency might have been down to the absence of historical links to the area.
Some £50 million of the new UK money will go towards rolling out 200 Ebola care units in local areas of Sierra Leone, where individuals who fear they may have picked up the infection can be checked and put into isolation. Another £20 million will go into the trust fund set up by UN secretary general Ban Ki-Moon, and £10 million into support for burials of Ebola victims.
Diane Sheard, UK director at the development campaign One, said: "One welcomes the announcement that the EU has pledged one billion euro to the fight against Ebola following the UK's additional £80 million promise to support vital frontline medical services in Sierra Leone.
"David Cameron threw down the gauntlet to other European leaders and has led by example. These commitments - both financial resources and human capacity - must match the enormity of the task ahead and must be quickly translated into life-saving action on the ground.
"To prevent further outbreaks over the long term, it is paramount that British and EU funding is targeted at both stemming the immediate crisis and in rebuilding and strengthening the health systems of those countries - some of the world's poorest - which are bearing the brunt of Ebola. People in Sierra Leone, Liberia and Guinea have already counted the cost in human lives. This tragedy must not be repeated."