Experts in Vietnam check if pigs catching bird flu

5.00am

HONG KONG - Experts in Vietnam are checking rumours that pigs have caught bird flu, which could result in a new, powerful stain of the disease that could be caught and passed on by people, a flu specialist said on Saturday.

Pigs are seen as an ideal vessel for bird and human viruses to mix and produce new strains that humans can catch.

"There are rumours of pigs being infected in Vietnam. WHO teams are there to see if pigs are infected," Jacqueline Katz, a flu expert at the US Centres for Disease Control and Prevention, told a conference in Hong Kong.

The H5N1 bird flu virus has killed eight people and decimated poultry populations in 10 Asian countries in two months.

All of the human victims are believed to have caught the flu from contact with infected chickens, the World Health Organisation says.

But experts fear the virus may mix with human flu and start the next pandemic among people with no immunity to it.

Pigs could facilitate that mixing.

"If there was a very widespread infection in pigs, then that would be a great concern that a pandemic strain might develop from it," Katz said.

Pigs are often kept next to chickens throughout Asia and medical experts have long fretted that such farming methods could allow cross-infection and mutation of viruses.

The H5N1 virus was first detected in humans in Hong Kong in 1997, when it killed six people.

It showed up a second time in humans in 2003, when a Hong Kong man and his son were infected. The father died.

But the virus is still considered to be inefficient in terms of human transmission as there is no known case of anyone having caught it from another person.

To minimise the risk, governments in afflicted countries have culled millions of chickens and ducks to reduce human exposure to the disease.

Experts are puzzled as to how the disease could have spread so quickly but suspicion has fallen on migratory birds that could have passed it to domestic poultry.

Mosquitoes can also pass on diseases such as dengue fever and West Nile fever.

"Diseases are moving with animals...we'll see more new exotic diseases moving to new areas," Duane Gubler, director of the Asia-Pacific Institute of Tropical Medicine and Infectious Diseases at the University of Hawaii, told the conference.

Katz said the bird flu virus had changed from the 1997 outbreak to 2003 and again in its latest appearance.

Experts had been ready to test two vaccine candidates developed for the 2003 strain when they were confronted with another form of the virus, and had to start again.

"New vaccines for the 2004 variant are now in development," Katz said.

- REUTERS