Son of American Ebola patient says she's 'smiling, even joking’

The American woman who was infected with the Ebola virus while working with a Christian aid group in Liberia is getting better and is even smiling, her son said today.

Speaking with NBC's Today Show, Jeremy Writebol said his mother, Nancy Writebol, 60, who was evacuated from Monrovia last week and was wheeled on a stretcher into a special isolation unit at Emory University Hospital in Atlanta, Georgia, has gotten physically better

"When she came in on Tuesday last week, we were really concerned that she wasn't going to make it. To see her wheeled out of the ambulance and in, I was on the floor sobbing."

"We've seen her get physically better, her eyes brighten up, smiling, even joking a little bit" he said.

Jeremy, who says he sees his mum twice a day through a hospital window, said doctors told him they are cautiously optimistic she'll recover. Nancy is the second patient to use experimental drug, Zmapp