WASHINGTON—The U.S. government will begin screening passengers arriving at five airports from West African countries affected by the Ebola outbreak, the White House announced this afternoon.

The five airports – John F. Kennedy International in New York, Newark, Chicago O’Hare, Atlanta and Washington Dulles—account for 94 percent of the passengers arriving each day from Liberia, Sierra Leone and Guinea, said White House press secretary Josh Earnest. And there are only about 150 such passengers each day at those airports, making it more feasible to screen people more intensively who come from or recently visited the affected countries.

The Liberian man who died of Ebola today in Dallas, Thomas Eric Duncan, arrived from Brussels at Dulles before flying to Dallas/Fort Worth Internatinoal.

“The vast majority of passengers from those countries would be subject to this additional layer of screening,” Earnest said.

He emphasized that most effective way to stop the spread of Ebola is to stop people exhibiting Ebola symptoms from flying, and that takes place most effectively in West Africa.

“That will counter and has countered the spread of Ebola,” he said, adding that pre-departure screening is only part of the process. Officials at U.S. airports have already been trying to spot travelers with potential Ebola symptoms.

Screening for fever will be conducted by Customs and Border Patrol, Coast Guard and personnel from the Centers for Disease Control and Prevention, Earnest said. And he said, the screening shouldn’t cause any “significant disruption to the broader traveling public.”

He wasn’t sure if travelers with a fever would be put into quarantine. The Department of Homeland Security will provide more details on the new procedures later today.

Duncan apparently had no fever until a few days after he arrived in Dallas, so it’s unclear whether the extra screening would have prevented him from boarding a flight at Dulles heading for D/FW.

Earnest conceded that there’s no way to screen people who are infected before they show symptoms — which is the point at which they become contagious.

“What we’re trying to do is quickly isolate cases of individuals who are showing symptoms” and therefore could spread the disease. “You can’t get it through the air. It’s not like the flu or catching a cold… What we’re trying to do is safeguard the global transportation infrastructure at the same time we’re protecting the American public.”

This article is reproduced with permission from Dallas Morning News. The article was first published on October 10, 2014.