DAKAR, Senegal — More than 10,000 people have been infected with Ebola, according to figures released Saturday by the World Health Organization, as the outbreak continues to spread.

Of those cases, 4,922 people have died.

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 United Nations health agency said Saturday that the number of confirmed, probable and suspected cases has risen to 10,141. Its figures show about 200 new cases since the last report, four days ago. The WHO also said 450 health care workers have been infected with Ebola as of Thursday.

Even those grisly tolls are likely an underestimate, the WHO 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 they may be lagging behind reality.

On Thursday, authorities confirmed that Eblola had spread to Mali, the sixth West African country affected; 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, according to the WHO. So far, 43 people are being monitored in isolation for signs of Ebola, and the organization said Saturday that authorities are continuing to look for more people at risk.

To help fight Ebola, the U.N. humanitarian flight service airlifted about 1 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.

#EbolaResponse BREAKING @WFP plane lands in #Mali with 1t of @WHO medical supply from Liberia after 1st case declared pic.twitter.com/BdLRla5jVJ

— WFP West Africa (@WFP_WAfrica) October 24, 2014

Speed is vital to #EbolaResonse: #WFP plane carrying 1 ton of @WHO medical supplies lands in #Mali on Friday evening pic.twitter.com/0q5S1SZx9W

— World Food Programme (@WFP) October 25, 2014

“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,” Denise Brown, the West Africa regional director for the U.N. food agency, said in a release.

The WFP said it has distributed food to 776,000 people in Liberia, Sierra Leone and Guinea since April.

Additional reporting by Mashable

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