DALLAS — The first person diagnosed with Ebola in the United States died on Wednesday, underscoring questions about the quality of care he received, and the government ordered five airports to start screening passengers from West Africa for fever.

Liberian national Thomas Eric Duncan died in an isolation ward of a Dallas hospital, 11 days after being admitted on Sept. 28.

The case has stirred attention and concern that someone with Ebola had been able to fly into the United States from Liberia, raising the specter that more passengers could arrive and spread the disease outside of West Africa, where nearly 4,000 people have died in three impoverished countries.

The White House said extra screening for fever will be carried out for arriving passengers from West Africa. The screening will start at New York’s John F. Kennedy airport from the weekend, and later be used at Newark Liberty, Washington Dulles, Chicago O’Hare and Hartsfield-Jackson Atlanta.

Duncan had been in critical condition and on a ventilator and kidney dialysis at Texas Health Presbyterian Hospital. He was given an experimental medication to try to keep him alive, starting Saturday, six days after being admitted.

Duncan was able to fly to the United States from Liberia because he did not have a fever when screened at the airport in the capital, Monrovia, and filled out a questionnaire saying he had not been in contact with anyone infected with Ebola.

Liberian officials have said Duncan lied on the questionnaire and had been in contact with a pregnant woman who later died.

Duncan was not screened on arrival in the United States. Starting this weekend, though, JFK airport will use a non-invasive device to take the temperature of passengers, who also will fill out detailed questionnaires created by the U.S. Centers for Disease Control and Prevention (CDC).

Canada said on Wednesday it would step up airport screening of people arriving from affected West African countries. Those who are ill or say they have been in contact with a sick person will have their temperature taken by a quarantine officer.