Every country in the world must come up with a plan urgently to deal with an inevitable influenza pandemic likely to be triggered by the bird flu virus that hit Asia this year, a top global health expert says.

“I believe we are closer now to a pandemic than at any time in recent years,” said Shigeru Omi, regional director for the Western Region of the World Health Organization (WHO).

“No country will be spared once it becomes pandemic,” he told a news conference on Friday.

“History has taught us that influenza pandemics occur on a regular cycle, with one appearing every 20 to 30 years. On this basis, the next one is overdue.

“We believe a pandemic is highly likely unless intensified international efforts are made to take control of the situation,” he said of the H5N1 avian flu virus, which has defied efforts to eradicate it in several Asian countries, most notably in Thailand.

The world would have to cooperate closely to stave off a pandemic by sharing information promptly and openly on the virus - such as how it spreads, why it hits children more easily than adults and how quickly it is mutating, Omi said.

“There is no single solution to solve this disease, you have to do many things,” he said.

“Vaccine wil protect you from the disease and reduce the impact individually. But vaccination alone will not prevent this outbreak,” he said.

“Each country has to come up with a plan because, as I said, a pandemic, it will happen.”

HUGE HUMAN TOLL

The WHO fears the next flu pandemic could infect 25 to 30 percent of the world’s more than 6 billion people and kill up to 7 million of them.

Two U.S. firms are working on a vaccine, but neither is likely to have one ready until March, well after the cooler Asian season in which the virus thrives best.

The H5N1 virus, which has already killed 20 Vietnamese and 12 Thais, arrived in Asia about a year ago, probably spread by migrating birds, especially wild fowl heading to warmer climes at the onset of the northern winter.

Governments have slaughtered tens of millions of poultry in a bid to eradicate it, but WHO experts say it is now probably a permanent fixture.

The wild birds that can carry the virus without falling ill are returning to Asia for the northern winter and, in an alarming development, domesticated ducks are showing they too can have the virus without showing it, Omi said.

Experts say a pandemic will emerge from an animal, most probably a pig, which can harbour both flu viruses that affect humans and the avian flu variety.

The two would mate and produce a virus to which people have no immunity, they say.

That has not happened yet, but Omi said the geographical spread and the impact of the H5N1 virus was unprecedented and had struck animals such as tigers and domesticated cats not previously known to be susceptible to avian flu viruses.

“We have found that the virus is resilient, very, very versatile,” Omi said.