Officials say Dallas nurse Amber Vinson may have shown Ebola symptoms around four days earlier than initially thought. A CDC rep says "we have started to look at the possibility that she had symptoms going back as far as Saturday. ... We can't rule out (that) she might have had the start of her illness on Friday," which is when she took Flight 1142 from Dallas-Fort Worth to Cleveland. The CDC is now trying to trace that flight's passengers, and the airline is notifying people who were on five subsequent flights involving the plane she returned home on. A source tells CNN Vinson experienced fatigue and muscle aches while in Ohio; 12 of her confirmed contacts there are under quarantine, including two bridal store employees. In other developments: