US President Barack Obama has vowed "much more aggressive" response to Ebola cases in the United States, and warned that in an age of frequent travel the disease could spread globally if the world does not respond to the "raging epidemic in West Africa".'

Obama sought on Wednesday to ease growing anxiety in the US, as a second nurse was diagnosed with Ebola after treating a patient in a Dallas hospital. That patient, Thomas Eric Duncan, died of Ebola on October 8.

In an interview with a local US television station, that nurse said she informed authorities several times that she had a slight fever before boarding a commercial flight, and was told that it was okay to fly. She has now been transferred to a hospital in the city of Atlanta for treatment.  

The president said he had directed the Centers for Disease Control and Prevention (CDC) to step up its response to new cases.

"We want a rapid response team, a SWAT team essentially, from the CDC to be on the ground as quickly as possible, hopefully within 24 hours, so that they are taking the local hospital step by step through what needs to be done," he said.

Live Box 201482572719796478

Obama spoke after cancelling a political campaign trip to convene a session of top Cabinet officials involved in the Ebola response both in the US and in the West African region, where the disease has been spreading at alarming rates.

The meeting included the top military commander General Martin Dempsey and defence chief Chuck Hagel.

Obama has been pressing the international community to step up its assistance in combating the disease.

Hours before Obama cancelled his trip, officials confirmed the infection of the second nurse who helped treat Duncan.

The Texas developments added a new domestic element to what has developed into an Ebola crisis in the West African countries of Guinea, Sierra Leone and Liberia.

'Controlled environment'

US government officials on Wednesday said the nurse should never have got on the plane.

Tom Frieden, director of the CDC, said no one else involved in Duncan's care would be allowed to travel "other than in a controlled environment''.

"We could've sent a more robust hospital infection control team and been more hands-on with the hospital from day one about exactly how this should be managed,'' he said on Tuesday.

Infected Ebola patients are not considered contagious until they have symptoms.

Frieden said it was unlikely that other passengers or airline crew members were at risk because the nurse did not have any vomiting or bleeding.

However, the CDC has alerted the 132 passengers aboard Monday's Flight 1143 from Cleveland to Dallas' Fort Worth on Monday "because of the proximity in time between the evening flight and first report of illness the following morning''.

The woman is being treated in Texas and will be flown to a specialist hospital in Atlanta where some previous Ebola patients have recovered.

Source: Agencies