FEATURE - Hong Kong Hunter Hot on the Trail of Deadly Bird Flu Virus
Date: 15-Sep-05
Country: HONG KONG
Author: Tan Ee Lyn
When I am not sleeping, I am working, most of the time on the H5N1," the 43-year-old China-born microbiologist who works at the University of Hong Kong said. Experts fear the virus will unleash the next pandemic and kill millions of people.
He got acquainted with the bug in 1997 when it made its first known jump to humans in Hong Kong, where it killed six people.
And since 2000, Guan has been able to track its spread all over China after testing more than 100,000 stool samples from domestic chickens, aquatic and wild birds.
When migratory birds started dying in Qinghai Lake in central China in April, his laboratory in Shantou in south China detected the bug in the carcasses, and Guan saw trouble brewing ahead.
With other scientists, such as US-based Robert Webster and Hong Kong-based Longlin Chen and Malik Peiris, they wrote in a Nature article in July that virus in Qinghai probably originated in southern China and would spread further among the wild birds.
Worse, those that survive could carry the bug as far away as the Indian subcontinent and Europe.
The virus has since been detected in regions north of China in Kazakhstan, Russia and Mongolia. It has also been found in China's southwestern regions of Xinjiang and Tibet, which borders Nepal and the rest of the Indian subcontinent.
EURASIA, AFRICA
Shaking his head, Guan says he fears the worst.
"The virus has gone back to nature ... Pakistan will get it sooner or later, and India. Birds in India will reach western Europe. From there they will go to the Middle East, then Africa," he said in an interview in his office at the University of Hong Kong.
"If the viral load is very heavy in migratory birds, all of Eurasia, Africa will be hit in one or two migrating seasons."
With H5N1 commanding a wider geographic distribution in Asia, Guan says it is a matter of time before it finds its way into more aquatic and wild birds, which will spread the virus further.
In many places in Asia, chickens and aquatic birds, like ducks and geese, are not segregated and cross-infection is common. Birds infected with H5N1 typically shed huge amounts of the virus in their droppings, which can infect other birds.
"With infection in poultry becoming bigger, water sources are contaminated. Migratory birds use the same water sources that aquatic birds use," he said, expounding a theory as to how the virus found its way into so many migratory birds recently.
"We should have stopped it when it was still (in poultry) within China. The best opportunity to contain it was between 1997 and 2001, before the big explosion in 2003," he said, referring to the rapid spread of the virus from late 2003 in southeast Asia, where the H5N1 is now endemic in poultry.
Since 2003, H5N1 has killed more than 60 people in Asia, most of whom caught the virus directly from infected birds. The greatest worry is it will mutate, become easily transmissible between people and set off a pandemic, killing millions.
Guan has observed an alarming rise in the transmission of H5N1 between poultry and aquatic birds in the last five years, which has resulted in many strains of the H5N1.
PROMISCUOUS
"The virus has eight gene segments, like eight parts of a marriage. In a couple, if one person has an affair, the marriage becomes unstable. The virus is the same. But it's made up not of two parts, but eight. If any one gets involved with other viruses, the whole virus gets destabilized," he said.
"It will feel unstable and search for other hosts. It tries to find the best-fitting host. This makes a virus jump species."
Since 2003, the H5N1 has infected and killed a number of tigers, leopards, cats and even civets.
Some have the potential ability to attack humans, warned Guan, who did his doctoral and post-doctoral studies at the St Jude's Children Hospital in Memphis, Tennessee.
Guan says the arduous task of tracking and anal
