WASHINGTON — Airline passengers arriving from Sierra Leone, Guinea and Liberia will soon face enhanced screening at five U.S. airports that receive over 94 percent of travelers from those Ebola-stricken West African nations.

The measures will begin Saturday at New York’s John F. Kennedy International Airport, which received nearly half of U.S.-bound travelers from those three countries in the year ending in July.

Beginning next week, Washington Dulles, Newark, N.J., Chicago O’Hare and Atlanta international airports will implement the same stepped-up screenings, according to a directive announced Wednesday by the U.S. Centers for Disease Control and Prevention.

The announcement about the new screenings came on the day Thomas Eric Duncan, a Liberian man who arrived in Dallas last month to visit his family, died in a Dallas hospital as a result of exposure to Ebola. He was the first patient in this country to be diagnosed with the deadly virus.

The CDC is sending extra personnel to all five airports to help implement the new medical screening initiative, which begins with Customs and Border Protection officers reviewing travelers’ passports.

The new guidelines call for travelers from the three West African nations to be taken to a special airport area, where they will be observed for signs of illness and asked a series of questions about their health and possible exposure to Ebola.

Medical personnel also will take their temperature with a non-contact thermometer. Those with fever, other symptoms, or who have indicated possible exposure, will be evaluated by a CDC quarantine officer, who will take their temperature again and assess their condition.

Those requiring further evaluation or monitoring will be referred to an appropriate public health agency.

Travelers from the three West African nations who have no symptoms, fever nor a history of exposure, will be given information about self-monitoring and will be asked to keep a daily log of their body temperature. They’ll also be asked to provide their contact information.

CDC Director Tom Frieden said the new initiative will provide an added layer of protection for a jittery nation hoping to keep the worst Ebola epidemic in history from spreading to the U.S.

“We believe these new measures will further protect the health of Americans, understanding that nothing we can do will get us to absolute zero risk until we end the Ebola epidemic in West Africa,” Frieden said in a statement.

All outbound airline passengers from affected West African countries are already screened for Ebola symptoms with assistance from the CDC. Of the estimated 36,000 people who have been screened in Africa in the last two months, only 77 were kept off airline flights because of illness. While many of the 77 had malaria, a common disease in West Africa, none were infected with Ebola.

Roger Dow, president of the U.S. Travel Association, a travel industry trade association, called the new measures “thoughtful and measured” and praised government officials for resisting “the temptation for draconian overreaction.”

“I personally thanked administration officials for resisting calls for an outright travel ban, which experts have uniformly called a harmful and counterproductive idea,” Dow said in a statement.

In a briefing at the State Department with British Foreign Secretary Philip Hammond, Secretary of State John Kerry echoed the call for open travel to West Africa.

“We need airlines to continue to operate in West Africa. And we need borders to remain open,” Kerry said.