The Nebraska hospital caring for a doctor who contracted Ebola said he is critically ill after being airlifted from Sierra Leone. "We will do everything humanly possible to help him fight this disease," Dr. Phil Smith, medical director of the Biocontainment Unit at Nebraska Medical Center, said in a statement. "This is an hour-by-hour situation." Salia, a permanent U.S. resident, was working in Sierra Leone as a surgeon. He was confirmed to have contracted Ebola on Tuesday. He was airlifted out of Sierra Leone at the request of his wife, a U.S. citizen. Salia is the tenth known Ebola case in the U.S. According to the World Health Organization, Ebola has claimed the lives of 5,177 people in Africa.