(Bloomberg) -- The Obama administration is considering screeningairline passengers for Ebola symptoms as they arrive in theU.S. from some West African nations, an approach that had beenpreviously rejected.

In advance of a meeting on the Ebola outbreak at theWhite House today, Dr. Thomas Frieden, director of the Centers forDisease Control, said President Barack Obama’s administration isdiscussing adding the additional step to passenger screenings nowbeing conducted in the African nations stricken by the disease.

“We’re looking at all options to protect Americans becausethat’s our No. 1 priority,” Frieden told the CNN televisionnetwork.

After a Liberian man, Thomas Eric Duncan, arrived in Dallas andbecame the first confirmed Ebolacase in the U.S., lawmakershave urged more aggressive action by U.S. border agents. Somecalled for a ban on any passengers from those nations, whileSenator Rob Portman, an Ohio Republican, said Frieden should haveagents specifically check travelersfor Ebola symptoms.

At this point, incoming travelers from West Africa get factsheets about the disease, but aren’t specifically tested for afever or asked if they had contact with someone who had thedisease. Duncan was asymptomatic while traveling. The New YorkTimes reported that while he was in Africa he accompanied aneighbor to the hospital in a taxi who later died of thedisease.

40,000 Passengers

The U.S. has had more than 40,000 visitors from West Africa inthe past six months, according to Frieden. Most connect to the U.S.through European airports. U.S. officials have also helped each ofthe three nations with Ebola outbreaks, Liberia, SierraLeone and Guinea, set up screening programs at their airports toidentify passengers with fevers or other symptoms.

“The most effective way to go about controlling this is toprevent those individuals from getting on a plane in the firstplace,” said Lisa Monaco, the White House homeland security andcounter-terrorism adviser, said on Oct. 3. “Since these measureshave been in place, dozens and dozens of people have been stoppedfrom getting on flights in the region.”

Meanwhile, Frieden warned that cutting off travel for passengersfrom West Africa might fuel the outbreak and raise the possibilityit spreads to other nations because it would make it harder to getaid into the countries.

Southwest Airlines

“Something we might do out of the best of intentions ofAmericans might actually increase Americans’ risk,” he said. Itwould also, “make it harder to get help in” to those nations, hesaid.

Southwest Airlines Co. Chief Executive Officer Gary Kelly said,“I don’t see the need to do anything differently.”

While Southwest doesn’t fly beyond the Caribbean and Mexico, itcould pick up international passengers who fly into several U.S.gateways for flights across the country. The Dallas-based carrierhasn’t taken any new steps beyond “over- communicating” factsabout Ebola to its employees, Kelly said after remarks ata Dallas meeting today.

“Everyone has their plans, everyone has their cleaningprograms,” he said. “There are FAA standards for all of thesethings. It feels like its very routine. If the protocols change,we’ll have to react to that, but right now it’s business asusual.”

Critical Condition

In Dallas, Duncan is now in critical condition at a hospital andpeople who came into contact with him are being monitored forsymptoms. Frieden said that this example shows that while there maybe isolated cases of the disease in the U.S., “I remain quiteconfident we will not have a widespread outbreak.”

“We will stop it in its tracks because we’ve got infectioncontrol in hospitals, and public health that tracks and isolatespeople if they get symptoms,” he said on ABC’s “This Week”yesterday. “But we have to recognize that, try as we might, untilthe outbreak is controlled in Africa, we can’t get the risk here tozero.”

--With assistance from Mary Schlangenstein inDallas.

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