New bird flu sparks fears

A new type of the bird flu common among poultry in Asia is becoming deadlier and could spark a pandemic by mixing with human viruses, a leading scientist has warned.

The H9N2 strain of bird flu is less lethal than the H5N1 strain that ravaged poultry farms in Asia earlier this year and crossed over to humans, killing 24 people. But it was more prevalent and a recent study said it had become more virulent, Leo Poon, a microbiologist at the University of Hong Kong, said. Poon was a co-author of the study, which was conducted by a team of US and Hong Kong scientists and published in the August issue of the Journal of Virology.

He said it was not clear why H9N2 had increased in virulence but warned of a pandemic if the strain mixed with a human virus. Tens of millions of chickens either died or were culled due to the H5N1 bird flu outbreak earlier this year. The virus also crossed over to humans, killing eight in Thailand and 16 in Vietnam. It has resurfaced among chickens in both countries recently.