US tightens arrival rules for Ebola

The United States has tightened restrictions on travellers arriving from the West African countries gripped by an Ebola outbreak, funnelling them into five airports with extra health checks.

The Department of Homeland Security on Tuesday ordered passengers whose journeys begin in Guinea, Liberia or Sierra Leone to fly to New York's JFK or Newark airports, Washington Dulles, Atlanta or Chicago.

There are no direct scheduled flights to the United States from the three countries at the heart of the Ebola epidemic, but travellers from the region can transfer through African and European hubs.

One Liberian with Ebola arrived in Dallas, Texas and infected at least two US health workers before dying, piling pressure on President Barack Obama's government to impose a flight ban.

Health authorities have set up additional screening for passengers at five airports which they say normally handle 96 per cent of the travellers arriving from the three worst hit countries.

But Tuesday's order would prevent travellers from Guinea, Liberia or Sierra Leone from transferring to flights to other US airports where they would not necessarily have to pass additional screening.

"If not already handled by the airlines, the few impacted travellers should contact the airlines for rebooking, as needed," Homeland Security Secretary Jeh Johnson said.

"We currently have in place measures to identify and screen anyone at all land, sea and air ports of entry into the United States who we have reason to believe has been present in Liberia, Sierra Leone or Guinea in the preceding 21 days."

The virus has killed more than 4500 people in West Africa this year, and stoked fears that it could spread beyond the three worst hit countries and become a global threat.

But small outbreaks in Senegal and Nigeria have been halted and, with no new confirmed infections in the United States for six days, authorities are hopeful they have now contained the danger.