HONG KONG - A leading virus expert urged health authorities around the world Sunday to stay vigilant even though the recent swine flu pandemic was less deadly than expected, warning that bird flu could spark the next global outbreak.
A World Health Organization official also defended the U.N.'s health body against accusations that it wasted governments' money and enriched pharmaceutical companies with its strong warnings during the swine flu outbreak's early days last year.
WHO declared the swine flu pandemic over last month. The latest death toll is just over 18,600 - far below the millions that were once predicted. The head of the global health body has credited good preparation and luck, since the H1N1 swine flu virus didn't mutate as some had feared.
But speaking to reporters on the sidelines of an influenza conference in Hong Kong, researcher Robert Webster warned against complacency.
"We may think we can relax and influenza is no longer a problem. I want to assure you that that is not the case," said Webster, chairman of the virology and molecular biology department at St. Jude Children's Research Hospital in Memphis, Tennessee.
Webster predicted that the next pandemic could be sparked by a virus that spreads from water fowl to pigs and then onto humans - such as the H5N1 strain of bird flu, which has killed 300 people over the past seven years.
He noted that after several years of decline, the number of bird flu cases in humans increased in 2009, lifted by an uptick of cases in Egypt.
"H5N1 can kill 61 percent of humans infected, but it doesn't know how to spread from human to human. But don't trust it because it could acquire that capacity. So we must stay vigilant," he said.