The UN chief Kofi Annan has named a special coordinator to lead a global strategy to contain it.
He is David Nabarro, a Briton is one of the leading World Health Organisation’s (WHO) public health experts.
“We expect the next (human) influenza pandemic to come at any time now. It is likely to be caused by a mutant of the virus that is currently causing bird flu in Asia,” Mr Nabarro said.
Mr Nabarra outlined a three-pronged strategy to deal with the threat.
“The avian flu epidemic has to be controlled if we are to prevent a human influenza pandemic,” he warned, saying this would be a key goal for his office.
“Let’s say the range of (human) deaths could be anything between five and 150 million. I believe the work we are doing over the next few months on prevention and preparedness will make the difference between for example whether the next pandemic leads us in the direction of 150 (million) or in the direction of five.”
He said the UN would need to work with governments, firms involved in chicken farming and communities who are close to chickens, particularly in Asia where birds are often very domesticated, to try to increase the separation between humans and birds.
Attention would also have to be paid to the migration of wild birds around the world, since the bird flu virus had been found in migrating geese, ducks and other wild fowl.
Mr Nabarro stressed the crucial importance of preparedness “so if there is a species jump, if the virus moves and mutates from the bird population to the human population, we are ready to respond, to neutralise it, to contain it and to delay the development of a major flu pandemic.”
“Most scientists reckon that there will be a very short interval between the discovery of the mutant virus that causes the next influenza pandemic and the time when that pandemic really starts to get out of control. It will be a matter of weeks,” Mr Nabarro said.
“The window of opportunity to delay a pandemic is short.”
WHO, the Food and Agriculture Organisation and the Paris-based World Organisation for Animal Health are working together, with backing from the World Bank and other UN agencies, to help countries deal with the looming threat.
The next phase, he said, would be detecting the unusual transmission of the virus with good epidemiology and good surveillance networks for human illness.
The virus would then have to be contained in affected populations through a mix of the anti-viral drug Tamiflu and vaccination with the most potent vaccines available.
Tamiflu can alleviate some symptoms and slow down the spread of the flu, but does not constitute a cure. It is not known whether those who take the drug continue to be carriers of the virus.
Another challenge, Mr Nabarro said, was “how to organise the world’s vaccine manufacturing capacity so that it can respond once we know the precise makeup of virus that causes the pandemic.”
“We’ve also got to get the message to everybody so that we get a response that has the right level of concern without leading to unreasonable panic,” he said.
The H5N1 variant of the disease has been known to scientists for decades as a latent killer within the world’s bird populations.
However, it became a global concern when in Hong Kong in 1997 the strain first mutated into a form lethal to humans, killing six people.
Since late 2003, large outbreaks of the disease have exploded among poultry flocks throughout Asia, leading to more than 60 human deaths. Millions of chickens and ducks were culled in efforts to halt the disease’s spread.