A Texas health care worker who treated a man who later died of Ebola has tested positive for the disease in a preliminary test, the second person to be diagnosed with the illness on US soil.

“We knew a second case could be a reality, and we’ve been preparing for this possibility,” said Dr David Lakey, commissioner of the Texas Department of State Health Services.

“We are broadening our team in Dallas and working with extreme diligence to prevent further spread.”

• Travellers set to be ‘screened’ for Ebola

The health care worker reported a low grade fever on Friday night and was isolated and referred for testing, Texas health services said in a statement. It did not further identify the worker nor detail how exposure to the virus occurred.

The statement added: “Health officials have interviewed the patient and are identifying any contacts or potential exposures. People who had contact with the health care worker after symptoms emerged will be monitored based on the nature of their interactions and the potential they were exposed to the virus.”

The health care worker was from Texas Health Presbyterian Hospital in Dallas, the hospital which treated Thomas Eric Duncan, the Liberian man who died on Wednesday.

US rolls out airport screening measures

On Saturday, US officials confirmed that New York’s JFK airport would roll out health screenings for travellers arriving from Ebola-hit West African nations.

Passengers arriving from Liberia, Sierra Leone and Guinea will have their temperatures taken, be assessed for signs of illness and answer questions about their health and exposure history, the US Centres for Disease Control and Prevention (CDC) said.

Suspected cases could be barred from travelling further and referred to nearby hospitals if necessary, CDC said.

JFK is the first airport to implement the screenings, and four other airports – Newark in New York, Chicago’s O’Hare, Washington’s Dulles and Atlanta international airport in Georgia – are set to start the checks next week.

Around 50 per cent of arrivals from the three West African countries pass though New York’s JFK airport.

Together, all five airports account for 94 per cent of all travellers coming into the United States from Guinea, Liberia and Sierra Leone, the worst-affected countries.

More than 4,000 people have died in the Ebola epidemic in West Africa since the start of the year, the World Health Organisation says.

– with ABC