Cpl. Zachary Wicker shows how to put gloves on while in germ-protective gear in Fort Bliss, Texas, Tuesday, October 14, 2014. About 500 Fort Bliss soldiers are preparing for deployment to West Africa where they will provide support in a military effort to contain the Ebola outbreak. (Juan Carlos Llorca/AP)

THE EBOLA tidal wave is still flooding West Africa, running ahead of all efforts to contain it. This is the most urgent crisis and the one that requires maximum effort. Bruce Aylward of the World Health Organization predicted Tuesday that the case load could reach 10,000 a week by December. Currently, the virus has caused 4,447 deaths and infected 8,914 patients, and there is disturbing new evidence that the mortality rate is now 70 percent, higher than previously thought. An exponential leap seems possible, and the international response is still lagging — pledges are only slowly being turned into treatment centers on the ground, patients are being turned away and told to go home and there remains a desperate need for health-care workers.

At the same time, the outbreak of the deadly virus has sliced through American politics and the media with a vengeance. Understandably, the specter of such a dangerous disease in the United States has bred fear. But it is remarkable how some public figures are inflaming that fear. Commentator Rush Limbaugh took flight on Tuesday, saying on the radio that “I don’t think anybody involved with Ebola knows what they’re doing. I don’t care if it’s the WHO or the Centers for Disease Control, I don’t think anybody knows what they’re doing.” This was an unfounded rant that can only deepen public disquiet. By contrast, in a vote of confidence and generosity, the Bill and Melinda Gates Foundation donated $50 million recently to the United Nations and governments that need the resources for emergency response to the crisis. On Tuesday, Facebook founder Mark Zuckerberg and his wife, Priscilla Chan, donated $25 million to the Centers for Disease Control and Prevention Foundation to help fight Ebola. These rapid philanthropic responses to the outbreak reflect the best of American ideals and values.

The arrival of an Ebola patient in Texas, followed by his death and the subsequent announcement that a hospital worker, Nina Pham, who treated him has tested positive for Ebola, has fueled dread that the disease could spread in the United States. One of the nation’s top public health authorities, CDC Director Thomas Frieden, had reassured the nation that the health-care system could handle Ebola if the virus landed here. Ms. Pham’s illness — it is still not known how she got it — has caused many to wonder, not unreasonably: Are hospitals really as prepared as officials have said? Is the system so fragile that Ebola could jump the fence in the United States?

One infected person, Ms. Pham, does not constitute an outbreak. But we think Dr. Frieden and others are wise to prepare for the worst, including by making sure that hospitals across the country know what to do if a patient shows symptoms that look like Ebola and have the ability to respond rapidly and effectively. At a time of tension, the nation’s public health leaders must not overpromise.