The first person diagnosed with Ebola in the United States died early Wednesday, as the government announced plans to step up screening of travelers at five of the nation’s busiest airports in an effort to prevent more cases of the deadly virus from reaching the country.

Thomas Eric Duncan, who traveled from Liberia late last month and had been fighting for his life in a Dallas hospital, died at 7:51 a.m., according to Texas Health Presbyterian Hospital in Dallas.

Duncan’s case attracted international headlines over the past week, revealing gaps in the readiness of U.S. hospitals to deal with Ebola’s arrival here and demonstrating how easily the virus could slip undetected from the epicenter of the outbreak in West Africa to virtually anywhere in the world.

His death also renewed questions about whether the hospital’s decision to initially send Duncan home before admitting him days later not only put others at risk for infection, but also hurt his chances for survival.

“It’s devastating,” said Princess Duo, 32, a longtime friend of Duncan’s fiancee. “It’s not just the fact that he’s dead. But it’s just the way in which it happened. That’s what hurts the most.”

As the scene in Dallas shifted from one of desperate hope to one of mourning, government officials on Wednesday outlined new screening measures for travelers entering the country from West Africa in coming days.

They include temperature-taking and questions about exposure to Ebola patients.

“It will give us the ability to isolate, evaluate and monitor travelers as needed,” President Obama said Wednesday in a conference call with state and local officials. “And we’ll be able to collect any contact information that’s necessary.”

The ramped-up screening will begin Saturday at New York’s John F. Kennedy International Airport, which has been used by nearly half of all travelers from the nations hit hardest by the Ebola epidemic during the past year.

The screening will be expanded over the next week to Washington’s Dulles International Airport, O’Hare International Airport in Chicago, Hartsfield-Jackson International Airport in Atlanta and Newark’s Liberty International Airport. About 150 passengers a day arrive in the United States from the affected areas, federal officials said Wednesday.

Together, the five airports account for nearly 95 percent of travelers from Guinea, Liberia and Sierra Leone — the three countries hit hardest by the crisis.

It’s the first time in recent history that the United States has conducted this type of screening. During the SARS epidemic in 2003, staff from the Centers for Disease Control and Prevention conducted visual screenings and observed passengers coming from affected countries for signs of illness.

More than a dozen drugs are being studied for treating Ebola and other filoviruses.

For the Ebola screening, travelers from Guinea, Sierra Leone and Liberia will be taken to airport areas set aside for screening. Customs and Border Protection staff will take their temperatures, look for signs of illness and ask questions about travel histories and possible exposure to the virus.

The screening areas are not meant as “long-term holding facilities or isolation facilities,” said Chris Paolino, a spokesman for Dulles airport.

Travelers who have a fever, other symptoms or worrisome answers on a health questionnaire will be checked more closely at a separate CDC quarantine station; CDC staff will take their temperature again and evaluate them. Travelers who need additional assessment will be referred to public health authorities; those who do not require additional checking will be asked to leave their contact information and will receive tips for self-monitoring.

Meanwhile, Texas Health Presbyterian Hospital said Wednesday that it had admitted a man who reported possible exposure to Ebola. CDC Director Tom Frieden said in a Wednesday briefing that the man had no “definite contact with Ebola or definite symptoms of Ebola.” The president of the Dallas County Sheriff’s Association told a local television station the patient was a deputy who had entered the apartment where Duncan had been staying.

Even as federal officials announced the new screening measures Wednesday, they acknowledged there is no way to prevent another Ebola case from entering the country, given that an infected person can carry the disease for a week or even longer before symptoms surface.

“We recognize that whatever we do, until the disease is controlled in Africa, we can’t get the risk to zero here,” Frieden said during his briefing.

Frieden also acknowledged that the screening could result in false positives because 1 in 5 travelers boarding planes in West Africa have a fever, most often caused by malaria.

Some global health experts said the screening is more likely a move to calm public fears.

“There has been intense political pressure on the president to do something, and what he did is the most measured thing he could do, but it still has the potential to have a lot of downsides,” said Lawrence Gostin, a global health professor at Georgetown University Law School and an adviser to the World Health Organization. People can game the system by taking medicine to suppress fever, he said.

For public health officials in Dallas, the worries over Ebola were far from over. Authorities said they continue to monitor dozens of people who came into contact with Duncan, including about 10 people who remain at high risk, such as close relatives.

Another challenge Wednesday was how to handle Duncan’s body. Ebola victims are at their most contagious after death.

The CDC has issued guidelines for safe handling of the remains of Ebola patients, which notes that “handling of human remains should be kept to a minimum.” The agency recommends cremating the body or performing a prompt burial in a hermetically sealed casket.

Duncan’s death brought difficult questions about why he died when other Ebola patients who have received care in the United States have, so far, survived.

The fact that he sought treatment at the hospital but initially was sent home remained a source of sadness and frustration. That lapse meant not only that Duncan could have exposed dozens of family members and others to the disease, but also that his prospects for recovery might have been diminished. As with many infectious diseases, the chances of survival increase the earlier medical care begins.

Some people close to Duncan alleged he was not properly treated because he was not American. “He is a Liberian man,” Massa Lloyd, a close friend of Duncan’s fiancee, said Wednesday. “The family feels he wasn’t getting the right treatment because he was an African man. They feel America is fighting only for the white man, not the black man.”

The Dallas hospital has insisted it treated Duncan as it would have any other patient.

Duncan did not receive ZMapp, the experimental drug that appears to have helped other Ebola patients, including two U.S. missionaries infected in Liberia and treated in Atlanta. Supplies of that drug have been exhausted.

But Duncan did receive an experimental antiviral drug known as brincidofovir, which is produced by Chimerix, a North Carolina-based biotech firm.

Another Ebola patient receiving brincidofovir, NBC cameraman Ashoka Mukpo, also on Wednesday was scheduled to receive a blood transfusion at a Nebraska hospital from Ebola survivor Kent Brantly, an American doctor infected while working at a missionary hospital in Liberia.

Angela Hewett, associate medical director of the biocontainment unit at the Nebraska Medical Center, knew that Brantly had donated blood to another Ebola patient at the hospital, physician Richard Sacra. She wanted to know whether Brantly would donate to Mukpo and contacted him.

Remarkably, Brantly’s blood type matched Mukpo’s blood type, just as it did Sacra’s. Brantly, who was traveling through the Midwest on Tuesday, stopped at a facility in Kansas City, Mo., and donated blood, which was then flown to Omaha.

Doctors believe that a transfusion of survivors’ blood could help Ebola patients by providing them with antibodies that the survivors develop to help overcome the disease.

A spokesman for Samaritan’s Purse, a Christian relief group, on Wednesday said Brantly had been contacted recently by the Dallas hospital treating Duncan to see whether he would donate blood for him if their blood types matched. Brantly said yes, but then never heard back.

“The assumption is they weren’t a match,” said Samaritan’s Purse spokesman Jeremy Blume. “He was never contacted again.”

Ashley Halsey III, Juliet Eilperin, Abby Phillip, Amy Ellis Nutt and DeNeen L. Brown in Dallas contributed to this report.