By Elise Viebeck - 10/03/14 11:11 AM EDT
Centers for Disease Control and Prevention (CDC) Director Tom Frieden vowed to "stop Ebola in its tracks" in the United States while acknowledging that the Dallas outbreak could become larger than one case.
"I'm not going to promise that we can stop this at just one case, but I can tell you we have the advantage because the right steps are being taken," Frieden wrote late Thursday in an op-ed for CNN.
Frieden is seeking to maintain public calm about the Dallas Ebola case while urging continued help for the epidemic in West Africa.
The Obama administration is facing a barrage of questions about the virus and its effort to respond, including why officials will not ban travel from the three countries most affected.
"Even if we tried to close the border, it wouldn't work," Frieden said Friday on MSNBC's "Morning Joe."
"People have a right to return, people transiting through could come in, and it would backfire because by isolating these countries will make it harder to help them."
Frieden also said the U.S. would be at risk until the epidemic in West Africa is contained.
"We all want and wish we would have something where we're at zero risk," he said. But beating Ebola in Africa is "the only way we'll do that."