David Cameron and other western leaders have recognised the need to do far more and far quicker to deal with the spread of Ebola after holding crisis talks.

The epidemic dominated a 75-minute conference call last night involving the Prime Minister and US President Barack Obama, French President Francois Hollande, German Chancellor Angela Merkel and Italian Prime ­Minister Matteo Renzi.

More than 4,000 people have already died in West Africa and concerns over efforts to prevent a wider global outbreak were fuelled when it emerged a second person to catch Ebola in the US had taken a flight with 132 others the day before suffering symptoms.

A Downing Street spokeswoman said: "Leaders agreed this was the most serious international public health emergency in recent years and that the international community needed to do much more and faster to halt the rise of the disease in the region. Each leader set out what they are doing to help the countries affected and then discussions focused on how to improve ­co-ordination of the international effort and to work together to address the most urgent priorities: increasing the amount of international spending on the issue; increasing the number of trained personnel working in the region to treat those affected and prevent the disease spreading; and evacuation procedures for workers affected."

The call came amid new fears about US efforts to control the spread of Ebola after two nurses flew on separate commercial flights the day before they were diagnosed with the disease.

Officials are trying to trace 132 passengers who shared a cabin of a flight with a nurse from Texas who was found to have the disease the following day. The plane was travelling from Cleveland to Dallas Fort Worth airport on Monday.

Another nurse, Amber Vinson, 29, who contracted Ebola, flew from Ohio to Dallas with a temperature before she was diagnosed this week.The hospital worker was involved in the care of a Liberian man who died of the disease last week at the Texas Health Presbyterian Hospital in Dallas.

Crew members on the plane said the nurse showed no symptoms of Ebola.

Mr Cameron is due to convene another meeting of the emergency committee, Cobra, this morning.