March 6, 2009

An outbreak of the deadly bird flu virus at a Hong Kong farm last year which led to the slaughter of 90,000 chickens was likely spread by wild birds, an investigation found Thursday (Mar 5).

The December outbreak was the first discovered at a Hong Kong poultry farm in six years, and raised fears about the city's bio-security measures and whether the deadly virus had mutated.

Thomas Sit, head of the government's investigation team, said the dust and dirt near the entrance of one of the two affected chicken sheds could have been contaminated by droppings from infected wild birds and then blown into the shed area by a gust of wind.

He added that other sources such as rodents or contaminated clothing of farm staff could not be eliminated. He also stated that genetic analysis showed the virus was of the type commonly found in southern China but it could have come from any location in Asia.

Sit said the farmer, who operated one of the city's major poultry farms, had been warned to improve bio-security measures, but would not face further action.

Cheung Siu-hing, director of the city's agriculture department, said authorities would strengthen bio-security measures for all Hong Kong poultry farms by increasing the number of inspections and testing of blood samples.

The outbreak was discovered after a dead chicken was found at the farm in the New Territories area of Hong Kong, near the border with China.

All chickens within a three-kilometre (1.9-mile) radius of the farm were slaughtered. Local farms were barred from selling chickens and eggs for 21 days and chicken imports were banned for the same period.

Hong Kong reported the world's first major bird flu outbreak among humans in 1997 with six fatalities. Since then, bird flu has killed more than 250 people worldwide.

Scientists fear the virus could mutate into a form which is much more easily transmissible between humans, triggering a global pandemic that could kill millions.