Ebola: US officials investigate Ohio flight Amber Vinson was on three days earlier

CDC say Texas nurse may have been showing symptoms as early as Friday

Ms Vinson travelled on Frontier Airlines (Getty Images)

Health officials are now racing to track down passengers on another flight with Amber Vinson, after it emerged the health care worker may have been showing symptoms of Ebola three days before testing positive for the virus.

The US Centers for Disease Control and Prevention (CDC) has now expanded its investigation to include the passengers who travelled with Ms Vinson on a flight from Dallas, Texas, to Cleveland, Ohio on 10 October.

Ms Vinson was cleared to fly from Ohio to Texas by the CDC the day before she tested positive for Ebola, despite reporting a slight temperature.

Health authorities were already looking to find the 132 other passengers on board that Frontier Airlines flight, who have been advised to call a CDC hotline.

CDC officials speaking in Ohio on Thursday said new information had led them to reassess the timeline of her illness.

CDC team leader Chris Braden told a conference: "We had started to look at the possibility that she had symptoms going back as far as Saturday.

"More information that has come through recently would say that we can’t rule out the fact that she might have had the start of her illness on Friday."

Ms Vinson and Nina Pham, who also contracted Ebola, were involved in providing care to Thomas Duncan, who died of the virus last week at the Texas Health Presbyterian hospital.

The National Institutes of Health said Ms Pham, 26, was taken from Texas Health Presbyterian Hospital in Dallas to the NIH centre in Bethesda, Maryland. The NIH facility has one of four isolation units in the US.

Ms Vinson has been transported to a biohazard infectious disease centre at Emory University Hospital in Atlanta.

The nurses wore protective gear including face shields, hazardous materials suits and protective footwear as they inserted catheters, drew blood and dealt with his body fluids, but still contracted Ebola.

Additional reporting by AP