Mali reported its first case of Ebola late Thursday, marking a major setback for West African efforts to contain the deadly virus that now has affected six countries in the region and left nearly 5,000 dead.

Health Minister Ousmane Kone made the announcement on Malian television, saying that the patient was a 2-year-old girl who had come from neighboring Guinea, where the Ebola epidemic began last December.

The child was tested for the virus Wednesday at a hospital in the Malian town of Kayes, which is about 375 miles from the capital of Bamako.

"The sick child and the people who were in contact with her in Kayes were immediately identified and taken care of," Kone said.

Ebola is spread through direct contact with the bodily fluids of sick people, and caregivers and health workers have borne the brunt of the crisis. Protocol calls for those who have been exposed to be isolated and monitored for symptoms for up to 21 days.

Health officials have long viewed Mali as one of the most vulnerable to Ebola's spread as the nation borders Guinea — one of the hardest-hit countries — and Senegal.

The World Health Organization said Wednesday that Ebola now has killed at least 4,877 people and infected 9,936 across West Africa. Nearly all the cases and deaths, though, have occurred in three countries — Liberia, Sierra Leone and Guinea.

Like the reported case in Mali, neighboring Senegal also had an imported case from Guinea. Senegal and Nigeria, though, both have now been declared Ebola-free after no new cases emerged after 42 days.

Also Thursday, dozens of people quarantined for Ebola monitoring in western Liberia were threatening to break out of isolation because they have no food, Liberian state radio reported.

Forty-three people were put in quarantine after four people died of Ebola in Jenewonda, a town near the Sierra Leonean border. The U.N. World Food Program said it was working to help those in isolation.

"WFP in Liberia heard about this community being isolated only two days ago via the radio and staff immediately began organizing a mission to bring food to the quarantined people," said spokesman Alexis Masciarelli in an email to The Associated Press.

Meanwhile, the head of the U.N. Mission for Ebola Emergency Response, Anthony Banbury, told a news conference Thursday in Sierra Leone's capital that "we are working to put this fire under control."

An internal U.N. World Health Organization report obtained by The Associated Press blames a series of blunders for allowing the epidemic to spiral out of control, notably the organization's own "failure to see that conditions for explosive spread were present right at the start."

"The world has never seen a serious, grave and complex crisis of this nature where people are dying every day with unsafe burial practices," he said.