New strain of bird flu uncovered in China

WASHINGTON — Scientists have discovered a new strain of bird flu that appears to sidestep current vaccines.

It's infecting people as well as poultry in Asia, and some researchers fear its evolution may have been steered by the vaccination programs designed to protect poultry from earlier types of the H5N1 flu.

The discovery by Yi Guan of the University of Hong Kong and colleagues is reported in today's issue of Proceedings of the National Academy of Sciences.

The new variant has become the primary version of the bird flu in several provinces of China and has spread to Hong Kong, Laos, Malaysia and Thailand, the researchers report. It is being called H5N1 Fujian-like, to distinguish it from earlier Hong Kong and Vietnam variants.

"We don't know what is driving this," said report co-author Dr. Robert Webster of St. Jude's Children's Research Hospital in Memphis, Tenn.

New vaccines will have to be developed, Webster said.

Many scientists are going to think the vaccination program encouraged the virus to evolve resistance, he added, but high-quality vaccines can reduce the level of illness and prevent emergence of variants.

While the new virus has infected people, there is no evidence that it can pass easily from person to person, Webster said. "But so long as the virus is out there in these numbers, it's going to be a continuing pandemic threat."

The H5N1 flu has devastated poultry in China and several other Southeast Asian countries and also has claimed more than 150 human lives. Most of the people affected lived close to flocks of chickens or other poultry.

Public-health authorities fear that the virus will mutate into a form that can spread easily among people, raising the potential for a worldwide pandemic like the one that killed millions in 1918. That worry has spurred efforts to develop vaccines for the virus as well as to test migrating wildfowl in an effort to follow the disease.

Dr. David Nabarro, who coordinates the United Nations' efforts against human and avian influenza, said the new data are a reminder that H5N1 is constantly evolving.

"I don't think it's a sign that we're getting any closer to pandemic flu," Nabarro said. "Frankly, I don't know how we're going to know when pandemic flu gets close. We're just going to get hit by it."

Material from the Los Angeles Times is included in this report.