Enhanced screening measures aimed at finding travelers infected with Ebola will be utilized at five of the busiest international airports in the United States, federal authorities said Wednesday.

These changes come more than a week after a man flew from Liberia to Texas and was later diagnosed with Ebola, which prompted calls for stricter screening at U.S. airports as the disease continues to ravage West Africa.

Travelers originating in the three West African countries hit hardest by the disease will be given questionnaires and have their temperatures taken at these U.S. airports, the Centers for Disease Control and Prevention and Department of Homeland Security announced Wednesday.

The new screening will begin at John F. Kennedy International Airport in New York on Saturday. Next week, it will be expanded to Washington Dulles International Airport outside Washington, D.C.; O’Hare International Airport, in Chicago; Hartsfield-Jackson International Airport in Atlanta; and Newark Liberty International Airport outside New York.

Additional CDC staff members will go to these airports and work with Customs and Border Patrol officers to perform the screening. Travelers from the three affected countries will be taken to an area set aside for screening, where they will have their temperatures taken with a thermometer that does not require contact. In addition, customs personnel will look for any signs of illness and asked a series of questions.

Any travelers with fever, other symptoms or worrisome answers on a health questionnaire will be checked out at a CDC quarantine station. Travelers who do not require additional checking or quarantine will be asked to leave their contact information and check their temperature every day.

These measures “will give us the ability to isolate, evaluate and monitor travelers as needed,” President Obama said Monday during a conference call to discuss Ebola with state and local officials.

“I’m confident that so long as we work together, and we’re operating with an appropriate sense of urgency that we will prevent an outbreak from happening here,” Obama said.

There are no direct flights on U.S. carriers from these countries to the United States, so people arrive through connections in other cities. More than 90 percent of people who fly to the United States from the three Ebola-ridden countries arrive at one of these five airports. During a recent 12-month period, nearly half of travelers from these countries flew through Kennedy Airport, the CDC says. Still, these people make up a very small portion of the number of people who fly internationally into the country.

About 150 people travel each day from these West African countries to the five airports that will have increased screening, according to the White House and the CDC. More than 90 million international passengers flew to the U.S. last year.

“The number of travelers is relatively small,” CDC Director Thomas Frieden said during a briefing Wednesday. “It’s not an effort that would be particularly disruptive to large numbers of people.”

Airlines for America, a trade group that represents the major U.S. airlines, said its members were cooperating with customs in the enhanced screening effort.

“This screening is being done out of an abundance of caution to protect the well-being of the American public while not disrupting travel to the United States,” said Jean Medina, the group’s spokeswoman.

Medina also pointed out that as the CDC has repeatedly said, there is no risk for air travelers, because Ebola cannot be transmitted through the air.

International passengers selected by U.S. Customs and Border Protection for additional screening at Dulles International Airport will be taken to airport terminal screening rooms established for that purpose several years ago, airport spokesman Chris Paolino said.

“They’re not meant as long-term holding facilities or isolation facilities,” Paolino said. “They’re intended as short-term facilities, while CDC would make a determination as to what to do with the individuals on a longer term basis.”​

He said the rooms are in the international terminal. Paolino said the Metropolitan Washington Airport Authority also maintains similar isolation rooms at Reagan National Airport, which it also operates, though international flights don’t land there.

White House press secretary Josh Earnest said Wednesday that incoming passengers from Ebola-hit countries will be screened at five U.S. airports. (Reuters)

The top five airports at which international travelers arrive in the United States were New York’s Kennedy, Miami, Los Angeles, Newark and Chicago. Much of this international air traffic originates from Canada, Mexico, Britain, Japan and Germany. ​

“Taking temperatures and learning more about passengers coming here from West Africa will provide another necessary line of defense against this epidemic,” Sen. Charles E. Schumer (D-N.Y.), one of the politicians who had been calling for increased screening, said in a statement Wednesday.

Here's how the virus spreads and how contact tracing works to stop outbreaks. (Gillian Brockell/The Washington Post)

Frieden had said this week that the agency was exploring ways to increase passenger screening in the wake of an Ebola diagnosis in Dallas, Tex.

“We’re working very intensively on the screening process,” Frieden said during a conference call with reporters Tuesday. “We’re looking at that entire process to see what more can be done.”

But Frieden again cautioned Wednesday that new methods could not eliminate the danger of a person with Ebola coming into the United States.

“We recognize that whatever we do, until the disease is controlled in Africa, we can’t get the risk to zero here,” he said “We may be able to reduce it.”

The CDC has had teams on the ground working to strengthen the screening of passengers leaving West Africa. This screening has included taking temperatures, keeping an eye out for other symptoms and having travelers fill out questionnaires.

He said the CDC methods have been used to screen more than 36,000 people over two months. And of those travelers, a small portion of whom were coming to the United States, only 77 people had a fever or other symptoms that caused them to be taken out of the line, he said. “As far as we know, none of those 77 people had Ebola,” Frieden noted.

Of course, these methods are not perfect, as was made clear when Thomas Eric Duncan filled out a questionnaire, had his temperature taken by a person trained by the CDC and boarded multiple flights on his way to Dallas, where he was diagnosed with Ebola. Duncan died Wednesday morning.

Juliet Eilperin contributed to this report.

[This post has been updated. First published: 11:02 a.m. Last updated: 5:01 p.m.]

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