TOP federal health officials in the US said they still don't know how two nurses caught Ebola from a patient, as criticism increased from lawmakers who questioned whether America is prepared to stop the deadly virus from spreading.
The revelation that one of the hospital nurses was cleared to fly on a commercial airline the day before she was diagnosed raised new alarms about the American response to the Ebola outbreak in West Africa.
The death toll has climbed above 4,500 in Africa, all but a few within Liberia, Sierra Leone and New Guinea, the World Health Organisation said.
President Barack Obama yesterday directed his administration to respond in a "much more aggressive way" to the threat and, for the second day in a row, cancelled his out-of-town trips to stay in Washington and monitor the Ebola response.
Even as Obama sought to calm new fears about Ebola, he cautioned against letting them overshadow the far more urgent crisis unfolding in West Africa. Underscoring his emphasis on international action, Obama called European leaders to discuss better coordination in the fight against Ebola in West Africa and to issue a call for more money and personnel to "to bend the curve of the epidemic".
Spain's government is wrestling with similar questions. The condition of a nursing assistant infected with Ebola at a Madrid hospital appeared to be improving, but a person who came in contact with her before she was hospitalised developed a fever and was being tested.
That second person is not a health care worker, a Spanish Health Ministry spokesman said.
Yesterday an Air France plane was isolated at Madrid's Barajas Airport because of a suspected Ebola case after a passenger was reported to have a fever and shivers, officials said.
The passenger, who had traveled from Lagos, Nigeria, was taken by ambulance with a driver wearing full protective gear to the city's Carlos III hospital, but the rest of the passengers were allowed to leave the plane as normal, Air France said in a statement.
Danish authorities were also testing a medical worker for Ebola from Doctors Without Borders who had been in West Africa.
Amid increasing global concern, France said that from tomorrow it will begin screening passengers who arrive at Paris' Charles de Gaulle airport on the once-daily flight from Guinea's capital.
In the US Customs and health officials at airports in Chicago, Atlanta, suburban Washington and Newark, New Jersey, were to begin taking the temperatures of passengers from the three hardest-hit West African countries yesterday. The screenings, using no-touch thermometers, started last Saturday at New York's Kennedy International Airport.
"Despite these latest incidents, we remain confident that our public health and health care systems can prevent an Ebola outbreak here," Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, said in prepared testimony for the hearing on Capitol Hill.
With hospitals and airports on heightened alert, Frieden said the CDC is receiving hundreds of requests for help in ruling out Ebola in travelers. So far 12 cases merited testing, he said, but the patient who later died at the Dallas hospital has been the sole traveller with the disease.
Frieden said investigators are still trying to figure out how the nurses caught the virus from that Liberian patient, Thomas Eric Duncan. In the meantime, he said, their cases show a need to strengthen the infection-control procedures that "allowed for exposure to the virus."
Duncan's death and the sick health care workers in the US and Spain "intensify our concern about the global health threat," said Dr Anthony Fauci, director of the Institute of Allergy and Infectious Diseases at the National Institutes of Health.
Frieden said that nurse Amber Joy Vinson never should have been allowed to fly on a commercial jet because she had been exposed to the virus while caring for the first Ebola patient.
Vinson was being monitored more closely since, Nina Pham, the first nurse involved in Duncan's care, was diagnosed with Ebola.
Last night it was revealed that Yale-New Haven Hospital in Connecticut was evaluating a patient with "Ebola-like symptoms".
The patient is one of two Yale University graduate epidemiology students who travelled to Liberia last month to advise the health ministry on using computers to track the disease, according to Laurence Grotheer, a spokesman for New Haven Mayor Toni Harp.