The US has no plans to eliminate travel from countries in West Africa suffering the worst Ebola outbreak on record, Dr Thomas Frieden, director of the US Centers for Disease Control and Prevention, said in a briefing on Monday.

"Enhanced" airport screenings began at John F. Kennedy International in New York City over the weekend, and will expand to four others beginning this Thursday, he said, including at Atlanta's Hartsfield-Jackson International.

The screening assesses whether arriving passengers have a fever, the first symptom of an Ebola infection, and requires those coming directly or indirectly from Liberia, Sierra Leone or Guinea to answer questions about their contact with any Ebola patients.

Someone can be infected with the Ebola virus but not show symptoms, however, so fever screening would not identify such a person. Thomas Eric Duncan, the first patient diagnosed with Ebola in the US, apparently had no fever when he landed in Dallas last month, but developed the disease days later and died last week.

Until the Ebola outbreak in West Africa is brought under control, Frieden said, "there is no way to get risk in the US to zero." – Reuters