JEFFREY BROWN:

The director of the U.S. Centers for Disease Control just returned from surveying the situation in West Africa. And in a press conference this afternoon, he too added strong words and warnings. Dr. Thomas Frieden joins us now from Atlanta.

And, Dr. Frieden, there was a level of urgency and concern put forward today that I don't think we have heard from you and other officials so far. Have we entered a new and frightening phase in all this?

DR. THOMAS FRIEDEN, Director, Centers for Disease Control and Prevention: Well, unfortunately, the situation is bad.

It's worse than I and others had feared. The number of cases is increasing rapidly. The human tragedy is heartbreaking. And we anticipate that, in the next few weeks, we're going to see significant further increases in cases and in the places where it's spreading.

So, this is definitely an epidemic and really the world's first epidemic of Ebola, meaning spreading widely. And it's spiraling out of control.

What's really important to understand is that we know how to under — we know how to control it. And there is this window of opportunity that's closing, but it's not too late. We have to act now. Urgency couldn't be higher. Speed is of the essence.