As Ebola continues to ravage West Africa and fears grow that the virus will spread around the globe, enhanced screenings began on Saturday at Kennedy Airport in New York.

Travelers coming from three hard-hit African countries are being singled out, having their temperatures taken and questioned about their possible exposure to Ebola. Kennedy was the first of five American airports to introduce Ebola screening protocols, and the new measures were the latest indication of the risk that the disease presented.

Airports in Canada and Europe plan to take similar measures in coming days.

But even as nations try to reassure anxious citizens that they are doing all they can to prevent an outbreak within their borders, public health officials cautioned that the only way to truly eliminate the threat posed by the virus would be to defeat it in West Africa.

“As Ebola continues its slow-motion incursion into developed countries, right now the U.S. and Spain, there is an understandable level of fear growing among people about this terrible virus, even though the chances of seeing anything like the calamity in western Africa is profoundly remote,” said Dr. Irwin Redlener, the director of the National Center for Disaster Preparedness at Columbia University and a special adviser to Mayor Bill de Blasio of New York.