"This is not just one case," says Tom Frieden, director of the Centers for Disease Control and Prevention. "It's a cluster." He's talking about the Ebola situation in Mali, where two people have likely died of the disease in Bamako, the capital, and two others have tested positive.
Hundreds more may have been exposed. Officials from the U.N., the World Health Organization, the government of Mali and the CDC are all calling for swift action to keep Mali from descending into the Ebola chaos that's hit neighboring Guinea, Liberia and Sierra Leone.