The illness was first reported in December. Fears of a more widespread outbreak arose this week when two cases were found in Thailand and one in Japan, carrying the same virus.

At least a half-dozen countries in Asia, including Thailand and Japan, have started screening incoming airline passengers from central China. Officials are concerned the disease may spread more widely as millions of Chinese workers travel home during the Lunar New Year.

Over the next few weeks, some 5,000 passengers are likely to be screened, said Dr Martin Cetron, director of CDC’s Division of Global Migration and Quarantine, at a news briefing.

JFK is the only airport in New York where the screening will take place, starting at 10pm Eastern time on Friday. Screening at San Francisco International and Los Angeles International will begin on Saturday.

More than 40 cases of the newly identified coronavirus have been confirmed in Asia, including two deaths – at least one involving a previous medical condition.

Most of the patients are believed to have contracted the virus from exposure to animals to a specific seafood and meat market in Wuhan, the epicentre of the outbreak, and it is unclear whether the diseases can spread from person to person.

Chinese authorities said that no illnesses were reported among several hundred health care workers caring for the patients. But a recent case in China was a patient who did not go to the markets. Researchers said human-to-human transmission cannot be ruled out.

The chance for an epidemic in the US is deemed low, the officer at the CDC said, and the agency’s response is preventive.

The CDC is deploying about 100 experts to the three airports.

China reports second death from Wuhan virus as Thailand finds another case

Roughly 60,000 to 65,000 people a year travel from Wuhan to the US. New York and San Francisco are the only two cities that have direct flights from Wuhan. Those passengers arriving in Los Angeles are on connecting flights.

Travellers will be asked to fill out questionnaires asking if they have symptoms like cough or fever, and whether they have visited meat or seafood markets in Wuhan.

Screeners will also use thermal scanners that can be pointed at the forehead or temple to look for fever. People with signs of the illness will be examined further, and those who seem likely to be infected will be sent on to area hospitals for further testing.

The only time the CDC has done airport screenings was in 2014, when health officials screened thousands of passengers from three West African countries for Ebola but detected no illnesses. In fact, one passenger who was infected but had no symptoms passed through the screenings and then developed symptoms after arriving in the United States.

The disease is caused by a coronavirus, a member of a family of viruses that can cause respiratory illnesses from colds to pneumonia.

A different coronavirus caused the Sars outbreak in 2003, which originated in China and was spread to other countries by travellers, infecting more than 8,000 people and killing nearly 800.

Sars, or severe acute respiratory syndrome, belongs to the coronavirus family, but Chinese state media say the illness in Wuhan is different from coronaviruses that have been identified in the past.

Wuhan virus: Japan case sounds alarm in Asia before Lunar New Year

Earlier laboratory tests ruled out Sars and Mers – Middle East respiratory syndrome – as well as influenza, bird flu, adenovirus and other common lung-infecting germs.

CDC officials said on Friday that they are not certain if China has begun screening passengers before they board planes to travel abroad, but it has been discussed.

The New York and San Francisco airports each receive three direct flights from Wuhan each week, CDC officials said. Los Angeles International gets a significant number of passengers who start their journeys in Wuhan but change planes in Beijing.