An American doctor stricken with the deadly Ebola virus while in Liberia and brought to the United States for treatment in a special isolation ward is improving, the top U.S. health official said on Sunday. Dr Kent Brantly was able to walk, with help, from an ambulance after he was flown on Saturday to Atlanta, where he is being treated by infectious disease specialists at Emory University Hospital. “It’s encouraging that he seems to be improving – that’s really important – and we’re hoping he’ll continue to improve,” said Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta. Frieden told CBS’s “Face the Nation” it was too soon to predict whether Brantly would survive, and a hospital spokesman said Emory did not expect to provide any updates on the doctor’s condition on Sunday. More