Story highlights New airport screening measures will affect travelers from Guinea, Liberia and Sierra Leone

They'll take effect at New York's JFK airport, then in Atlanta, Chicago, Newark and Dulles

Official: U.S. can track those traveling from West Africa via connecting flights

CDC director: "We can't get the risk to zero here in the interconnected world"

One person has come to the United States and come down with Ebola here.

Authorities want to keep it that way.

To that end, the Centers for Disease Control and Prevention announced Wednesday beefed-up measures at five of America's biggest, busiest airports aimed at preventing the deadly virus' further spread.

While talk about preventing Ebola's spread abounds everywhere from coffee shops to TV news, this intervention won't affect a lot of people.

It applies only to about 150 people a day, by CDC Director Dr. Tom Frieden's estimate, arriving in the United States after having recently traveled from Ebolva-ravaged West African nations of Guinea, Liberia and Sierra Leone.

These travelers will get special treatment, including having their temperature taken and answering questions about whether they've been exposed to anyone with Ebola. The idea is to stop anyone with warning signs from getting past the airport gates, and into the U.S. public, before they can possibly spread the virus any further.

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But, Frieden cautioned, this isn't some sort of magic solution.

U.S. officials will likely discover some people have fevers or have had contacts with Ebola sufferers, only to find out they don't have the virus. Someone can still unknowingly come to the United States and show no signs of it, since it can take up to 21 days for someone to feel sick. Plus, there are more ways than ever for people to cross communities, cross borders, cross oceans and spread a virus like Ebola.

"We are stepping up protection for people, (and) we will continuously look at ways that we can increase the safety of Americans," Frieden told reporters. "(But) whatever we do can't get the risk to zero here in the interconnected world that we live in today."

New policy in place of 5 of America's busiest airports

Some of the measures to halt Ebola's spread are already happening -- in West Africa.

The U.S. government has been involved in efforts at international airports in the hardest-hit nations to question travelers about their health and exposure to Ebola, as well as take their temperature using what Frieden describes as FDA-approved devices.

During those screenings, 74 people with fevers and three more with other symptoms were stopped from boarding planes, according to Frieden. None of those are thought to have Ebola, something the CDC director attributed to the fact that high temperatures also are a symptom of malaria, a common ailment in Africa spread by mosquitoes, but not person-to-person.

The U.S. process for now will be in effect in only five airports -- where 94% of all travelers from West Africa enter the United States.

It will start Saturday at New York's John F. Kennedy International Airport, which has nearly half of all such passengers. The same thing will roll out next week at Dulles International Airport outside the nation's capital, Newark Liberty International Airport in northern New Jersey, O'Hare International Airport in Chicago and Hartsfield-Jackson Atlanta International Airport.

Here's how it will work.

It starts with U.S. authorities identifying anyone who'd recently been in West Africa, whether they flew in directly or via a connecting flight.

Alejandro Mayorkas, deputy secretary of the Department of Homeland Security, explained that "we have in our screening capabilities the ability to identify individuals traveling not only with respect to the last point of departure but the point of origin."

"So ... we can, in fact, identify the full journey of the individual arriving in the United States," said Mayorkas.

Customs and Border Protection -- the federal agency charged with safeguarding U.S. borders and airports -- will take the lead, escorting pinpointed travelers to a what Mayorkas called a "quarantine station." There, they will be asked questions about their health and possible exposure to Ebola, something that might tip off authorities that they might pose a risk.

These CBP officers, who won't be wearing any masks, will also place a non-contact thermometer over travelers' foreheads to take their temperature, since having a fever is one symptom of Ebola.

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Photos: The Ebola epidemic Photos: The Ebola epidemic An Ebola survivor participates in a study in Monrovia, Liberia, on June 17, 2015. The country launched a five-year study to unravel the mystery of the long-term health effects that plague survivors of the viral disease. Since the epidemic started more than a year ago in a remote village in Guinea, more than 11,000 people have died, the vast majority in three West African nations, according to the latest numbers from the World Health Organization . And that number is believed to be low, since there was widespread under-reporting of cases, according to WHO. Hide Caption 1 of 45 Photos: The Ebola epidemic Women in Monrovia celebrate after the World Health Organization declared Liberia Ebola-free on May 9, 2015. Other cases have recurred since, however. Two people in Liberia have died of the disease since the end of June, just weeks after the WHO declared the nation free of the disease. Hide Caption 2 of 45 Photos: The Ebola epidemic A man walks past an Ebola awareness painting in Monrovia on March 22, 2015. Hide Caption 3 of 45 Photos: The Ebola epidemic Soldiers from the U.S. Army's 101st Airborne Division walk across the tarmac at Campbell Army Airfield before reuniting with their families at a homecoming ceremony March 21, 2015 in Fort Campbell, Kentucky. The 162 soldiers were deployed in Liberia, where they helped fight the spread of Ebola. Hide Caption 4 of 45 Photos: The Ebola epidemic Relatives weep for a loved one who it was believed died from Ebola, at a graveyard on the outskirts of Monrovia on March 11, 2015. Hide Caption 5 of 45 Photos: The Ebola epidemic Doctors Without Borders staffer Alex Eilert Paulsen watches as mattresses and bed frames burn at the Ebola Treatment Unit in Paynesville, Liberia, on January 31, 2015. The organization reduced its number of beds from 250 to 30 as gains were made in battling the virus. Hide Caption 6 of 45 Photos: The Ebola epidemic Pauline Cafferkey, a Scottish woman diagnosed with Ebola, is put on a plane in Glasgow, Scotland, on December 30, 2014. Cafferkey, a 39-year-old nurse who volunteered in Sierra Leone, was being transported to London for treatment. Hide Caption 7 of 45 Photos: The Ebola epidemic A child who survived the Ebola virus is fed by another survivor at a treatment center on the outskirts of Freetown, Sierra Leone, on November 11, 2014. Hide Caption 8 of 45 Photos: The Ebola epidemic Health workers in Monrovia cover the body of a man suspected of dying from the Ebola virus on October 31, 2014. Hide Caption 9 of 45 Photos: The Ebola epidemic Kaci Hickox leaves her home in Fort Kent, Maine, to take a bike ride with her boyfriend on October 30, 2014. Hickox, a nurse, recently returned to the United States from West Africa, where she treated Ebola victims. State authorities wanted her to avoid public places for 21 days -- the virus' incubation period. But Hickox, who twice tested negative for Ebola, said she would defy efforts to keep her quarantined at home. Hide Caption 10 of 45 Photos: The Ebola epidemic Health officials in Nairobi, Kenya, prepare to screen passengers arriving at the Jomo Kenyatta International Airport on October 28, 2014. Hide Caption 11 of 45 Photos: The Ebola epidemic U.S. President Barack Obama hugs Ebola survivor Nina Pham in the Oval Office of the White House on October 24, 2014. Pham, one of two Dallas nurses diagnosed with the virus, was declared Ebola-free after being treated at a hospital in Bethesda, Maryland. The other nurse, Amber Vinson (not pictured), was treated in Atlanta and also declared Ebola-free. Hide Caption 12 of 45 Photos: The Ebola epidemic Health workers in Port Loko, Sierra Leone, transport the body of a person who is suspected to have died of Ebola on October 21, 2014. Hide Caption 13 of 45 Photos: The Ebola epidemic Health workers bury a body on the outskirts of Monrovia on October 20, 2014. Hide Caption 14 of 45 Photos: The Ebola epidemic Garteh Korkoryah, center, is comforted during a memorial service for her son, Thomas Eric Duncan, on October 18, 2014, in Salisbury, North Carolina. Duncan, a 42-year-old Liberian citizen, died October 8 in a Dallas hospital. He was in the country to visit his son and his son's mother, and he was the first person in the United States to be diagnosed with Ebola. Hide Caption 15 of 45 Photos: The Ebola epidemic Boys run from blowing dust as a U.S. military aircraft leaves the construction site of an Ebola treatment center in Tubmanburg, Liberia, on October 15, 2014. Hide Caption 16 of 45 Photos: The Ebola epidemic Aid workers from the Liberian Medical Renaissance League stage an Ebola awareness event October 15, 2014, in Monrovia. The group performs street dramas throughout Monrovia to educate the public on Ebola symptoms and how to handle people who are infected with the virus. Hide Caption 17 of 45 Photos: The Ebola epidemic Ebola survivors prepare to leave a Doctors Without Borders treatment center after recovering from the virus in Paynesville, Liberia, on October 12, 2014. Hide Caption 18 of 45 Photos: The Ebola epidemic A man dressed in protective clothing treats the front porch of a Dallas apartment on October 12, 2014. The apartment is home to one of the two nurses who were diagnosed with Ebola after treating Thomas Eric Duncan, a Liberian national who traveled to Dallas and later died from the virus. Hide Caption 19 of 45 Photos: The Ebola epidemic A woman crawls toward the body of her sister as a burial team takes her away for cremation October 10, 2014, in Monrovia. The sister had died from Ebola earlier in the morning while trying to walk to a treatment center, according to her relatives. Hide Caption 20 of 45 Photos: The Ebola epidemic A man digs a grave on October 7, 2014, outside an Ebola treatment center near Gbarnga, Liberia. Hide Caption 21 of 45 Photos: The Ebola epidemic A person peeks out from the Dallas apartment where Thomas Eric Duncan, the first person diagnosed with the Ebola virus in the United States, was staying on October 3, 2014. Hide Caption 22 of 45 Photos: The Ebola epidemic A girl cries as community activists approach her outside her Monrovia home on October 2, 2014, a day after her mother was taken to an Ebola ward. Hide Caption 23 of 45 Photos: The Ebola epidemic A health official uses a thermometer September 29, 2014, to screen a Ukrainian crew member on the deck of a cargo ship at the Apapa port in Lagos, Nigeria. Hide Caption 24 of 45 Photos: The Ebola epidemic Workers move a building into place as part of a new Ebola treatment center in Monrovia on September 28, 2014. Hide Caption 25 of 45 Photos: The Ebola epidemic Medics load an Ebola patient onto a plane at Sierra Leone's Freetown-Lungi International Airport on September 22, 2014. Hide Caption 26 of 45 Photos: The Ebola epidemic A few people are seen in Freetown during a three-day nationwide lockdown on September 21, 2014. In an attempt to curb the spread of the Ebola virus, people in Sierra Leone were told to stay in their homes. Hide Caption 27 of 45 Photos: The Ebola epidemic Supplies wait to be loaded onto an aircraft at New York's John F. Kennedy International Airport on September 20, 2014. It was the largest single shipment of aid to the Ebola zone to date, and it was coordinated by the Clinton Global Initiative and other U.S. aid organizations. Hide Caption 28 of 45 Photos: The Ebola epidemic A child stops on a Monrovia street September 12, 2014, to look at a man who is suspected of suffering from Ebola. Hide Caption 29 of 45 Photos: The Ebola epidemic After an Ebola case was confirmed in Senegal, people load cars with household items as they prepare to cross into Guinea from the border town of Diaobe, Senegal, on September 3, 2014. Hide Caption 30 of 45 Photos: The Ebola epidemic A health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia on August 29, 2014. Hide Caption 31 of 45 Photos: The Ebola epidemic A burial team from the Liberian Ministry of Health unloads bodies of Ebola victims onto a funeral pyre at a crematorium in Marshall, Liberia, on August 22, 2014. Hide Caption 32 of 45 Photos: The Ebola epidemic Dr. Kent Brantly leaves Emory University Hospital on August 21, 2014, after being declared no longer infectious from the Ebola virus. Brantly was one of two American missionaries brought to Emory for treatment of the deadly virus. Hide Caption 33 of 45 Photos: The Ebola epidemic An Ebola Task Force soldier beats a local resident while enforcing a quarantine on the West Point slum on August 20, 2014. Hide Caption 34 of 45 Photos: The Ebola epidemic Local residents gather around a very sick Saah Exco, 10, in a back alley of the West Point slum on August 19, 2014. The boy was one of the patients that was pulled out of a holding center for suspected Ebola patients after the facility was overrun and closed by a mob on August 16. A local clinic then refused to treat Saah, according to residents, because of the danger of infection. Although he was never tested for Ebola, Saah's mother and brother died in the holding center. Hide Caption 35 of 45 Photos: The Ebola epidemic Workers prepare the new Ebola treatment center on August 17, 2014. Hide Caption 36 of 45 Photos: The Ebola epidemic Liberian police depart after firing shots in the air while trying to protect an Ebola burial team in the West Point slum of Monrovia on August 16, 2014. A crowd of several hundred local residents reportedly drove away the burial team and their police escort. The mob then forced open an Ebola isolation ward and took patients out, saying the Ebola epidemic is a hoax. Hide Caption 37 of 45 Photos: The Ebola epidemic A health worker disinfects a corpse after a man died in a classroom being used as an Ebola isolation ward August 15, 2014, in Monrovia. Hide Caption 38 of 45 Photos: The Ebola epidemic Aid worker Nancy Writebol, wearing a protective suit, gets wheeled on a gurney into Emory University Hospital in Atlanta on August 5, 2014. A medical plane flew Writebol from Liberia to the United States after she and her colleague Dr. Kent Brantly were infected with the Ebola virus in the West African country. Hide Caption 39 of 45 Photos: The Ebola epidemic Members of Doctors Without Borders adjust tents in the isolation area in Kailahun on July 20, 2014. Hide Caption 40 of 45 Photos: The Ebola epidemic Boots dry in the Ebola treatment center in Kailahun on July 20, 2014. Hide Caption 41 of 45 Photos: The Ebola epidemic Dr. Jose Rovira of the World Health Organization takes a swab from a suspected Ebola victim in Pendembu, Sierra Leone, on July 18, 2014. Hide Caption 42 of 45 Photos: The Ebola epidemic Red Cross volunteers disinfect each other with chlorine after removing the body of an Ebola victim from a house in Pendembu on July 18, 2014. Hide Caption 43 of 45 Photos: The Ebola epidemic A scientist separates blood cells from plasma cells to isolate any Ebola RNA and test for the virus April 3, 2014, at the European Mobile Laboratory in Gueckedou, Guinea. Hide Caption 44 of 45 Photos: The Ebola epidemic Health specialists work March 31, 2014, at an isolation ward for patients at the facility in southern Guinea. Hide Caption 45 of 45

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If there are any red flags, the person will be evaluated by a CDC public health officer on site. He or she will then be given the OK to go, taken to a hospital or be referred to a local health department for monitoring and support.

All passengers who fly from West Africa will be given information about how to monitor themselves for possible symptoms, will be asked to log their temperature daily and be asked to provide their contact information to authorities.

Debate if more travel restrictions necessary

The only person to be diagnosed with Ebola in the United States, Thomas Eric Duncan , died Wednesday in a Dallas hospital.

Duncan traveled from Liberia, via Belgium, before arriving in Texas on September 20. It's not likely the stepped-up screening would have affected him, according to Frieden, because he didn't appear to show signs of the virus until a few days after his arrival.

There are many more like him, people who have spent time in West Africa and been exposed, whether they know it or not, to the disease. Frieden called the outbreak "unprecedented," given how quickly its spread through the regions.

According to the World Health Organization , more than 800 people have been infected with Ebola and at least 3,800 have died. Authorities have said the actual numbers are probably much higher, because many people may have died before authorities firmly identified Ebola as a cause, and others -- like Duncan -- may have the disease without knowing it or reporting it to officials.

And things aren't getting any better. According to a WHO update released Wednesday, "the situation in Guinea, Liberia and Sierra Leone continues to deteriorate, with widespread and persistent transmission of (Ebola)."

This alarming trend -- and the fact that there's been at least one person to bring Ebola unknowingly into the United States -- has spurred some calls to stop on all travel into the United States from West Africa so long as the virus is spreading.

Sen. Bill Nelson, a Florida Democrat, has publicly urged Secretary of State John Kerry to suspend U.S. travel visas of those from the affected region for any "unnecessary travel" and not to issue new visas.

The Rev. Jesse Jackson, a prominent civil rights leader who has served as a spokesman for Duncan's family, argued that such measures will hurt the economies of longtime American allies such as Liberia.

"We should quarantine the disease, not quarantine nations and not quarantine airline flights," the civil rights leader said. "We should not panic."

Frieden, the CDC director, also spoke against such a ban, arguing that severe travel restrictions will create more problems than they solve.

"It makes it hard to get health workers in, because they can't get out," he said. "If we make it harder to respond to the outbreak in West Africa, it will spread not only in those three countries (in West Africa hit hardest by Ebola) but to other parts of Africa and ultimately increase the risk here" in the United States."