Experts urged governments on Thursday to do more to prepare for a possible influenza pandemic and beef up surveillance on the spread of bird flu in all animals and humans.

The H5N1 bird flu virus is widely regarded as a possible trigger for the world´s next influenza pandemic because of its high mortality rate in humans and its rapid spread among birds across the globe in recent years.

But from disease surveillance to vaccine manufacturing and mundane logistical details, experts at a conference on avian flu and other infectious diseases in Singapore said not enough was being done.

"There has got to be an increase in (vaccine) manufacturing facilities. In a pandemic, there would be a lot of difficulty in securing vaccines from producers," said Peter Palese, a microbiology professor at the Mount Sinai School of Medicine in New York.

Palese urged governments to prepare in advance, saying: "Lots of problems have to be solved."

The world´s total flu vaccine production capacity is only about 350 million doses per year, a mere fraction compared to a world population of more than 6 billion people.

The shortfall becomes even more stark with a few drugmakers now promoting "multiple doses" for each person for better protection.

The H5N1 virus remains largely a bird disease and is hard for humans to catch. But it has killed 154 people since late 2003 and there are now several strains of the virus in circulation.

It is considered a novel virus against which people have no natural immunity, which partly explains its unusually high mortality rate of 60 percent.

This also underscores the threat to humanity should the virus evolve into a form that easily spreads from person to person.

NOT ENOUGH SYRINGES AND NEEDLES

Drugmakers told the conference they were trying to get around simple but daunting logistical problems in developing H5N1 vaccines for humans.

"Syringes and needles will be in short supply in the event of a pandemic," said James Young, president of research and development at MedImmune Inc, which markets a nasal spray vaccine that fights the common flu.

"We are looking at changeable tips -- after spraying into the nose of one person, you can change the tip and go to the next person," he said.

The conference also heard repeated calls for wider and tighter surveillance of the H5N1 virus in birds.

Nearly all human victims of H5N1 caught the virus from sick or dead chickens and one obvious way to prevent a pandemic would be to wipe out the disease in birds.

But such intervention is easier said than done.

In countries such as Indonesia and China where rural households habitually keep small numbers of chickens, the spread of the disease has often gone unreported, hampering efforts to stamp out the virus.

"There needs to be a greater amount of surveillance data collected and shared," said Frederick Hayden, a University of Virginia virologist now working on global flu planning for the World Health Organization.

"More information on (the disease) in swine, cats and dogs will make sense."