Alert over Ebola was delayed by two months

The Ebola epidemic centred on Guinea was, by early June last year, the deadliest ever recorded. Foreign workers were being evacuated and leading disease fighters warned the virus could soon spread across West Africa.

But the World Health Organisation resisted sounding the alarm until August, partly for political reasons, despite the fact that senior staff in Africa proposed doing so in June, emails have revealed. The two-month delay, some argue, may have cost lives. More than 10,000 are believed to have been killed by the virus since WHO first announced the outbreak a year ago.

The WHO has acknowledged acting too slowly to control the epidemic. In its defence, the agency says the virus's spread was unprecedented and blames several factors, including lack of resources and local intelligence.

Internal documents, however, show WHO's top leaders were informed of how dire the situation was. But they held off on declaring an emergency in part because it could have angered the countries involved, interfered with their mining interests or restricted the Muslim pilgrimage to Mecca in October.

Declaring an emergency was "a last resort," Dr Sylvie Briand, who runs WHO's pandemic and epidemic diseases department, said in a June 5 email to a colleague who floated the idea. "It may be more efficient to use other diplomatic means for now."

Five days after Briand's email, WHO Director General Dr Margaret Chan Fung Fu-chun - who previously served as Director of Health in Hong Kong - was sent a memo that warned cases might soon appear in Mali, Ivory Coast and Guinea Bissau. But it went on to say declaring an international emergency or even convening a committee to discuss it "could be seen as a hostile act".

"That's like saying you don't want to call the fire department because you're afraid the trucks will create a disturbance," said Michael Osterholm, an expert at the University of Minnesota.