November 26, 2004

WHO: Bird Flu Could Cause Next Pandemic

BANGKOK, Thailand -- After almost a year of trying to bring Asia's bird flu under control, World Health Organization experts are now warning the disease is the most likely candidate to cause the world's next pandemic, with the possibility of as many as 7 million deaths.

"I believe we are closer now to a pandemic than at any time in recent years," Shigeru Omi, Western Pacific regional director of WHO, said Friday at a regional meeting about the disease.

"The current outbreak (of avian influenza) in poultry is historically unprecedented in terms of geographical spread and impact," he said. "This virus appears to be not only very resilient, but also extremely versatile."

WHO's global influenza expert, Klaus Stohr, said Thursday that the H5N1 bird flu virus - which has killed 32 people in Thailand and Vietnam and millions of chickens across Asia this year - "is certainly the most likely one that will cause the next pandemic."

Influenza pandemics historically occur every 20 to 30 years when the genetic makeup of a flu strain changes so dramatically that people have little or no immunity built up from previous flu bouts.

"On this basis, the next one is overdue," Omi said.

Health officials fear bird flu could combine with a human flu virus, creating a new form that could spread rapidly throughout the world.

Health ministers from 13 Asian countries pledged at the meeting to intensify their cooperation in an attempt to ward off the possible pandemic and to prepare contingency plans to deal with it.

Omi told the meeting that the region must reduce bird flu's threat to humans by changing farming practices. "This means a thorough overhaul of animal husbandry practices, and the way animals are raised for food in the region. I believe that anything less than that will only result in further threats to public health," he explained.

Hong Kong Health Secretary York Y.N. Chow said his government has set up very strict security in chicken farms to segregate humans and chickens, and tried to minimize contact between wild birds and chickens.

Chow said Hong Kong has also prevented contamination by setting up "rest days" in wholesale markets, meaning that a new batch of chickens is delivered every four days after a previous batch is all slaughtered.

Chickens, ducks and other animals are often allowed to roam freely on small Southeast Asian farms, and often come into close contact with wild animals and with family members.

Some animal health experts have been promoting so-called "closed-system farming," in which poultry are raised in a sealed environment where they face minimal exposure to outside infections. But the system is likely to be prohibitively expensive for many poor farmers.

The WHO says a pandemic could cause an estimated 2 million to 7 million deaths and make billions of people ill.


On the Net:

World Health Organization: http://www.who.int