Health officials mobilize to address Texas bird flu

A Texas chicken flock was diagnosed with an "extremely infectious and fatal" form of bird flu on Monday, and federal health officials began monitoring area farm workers as a precaution against the first US outbreak of a severe form of the disease in 20 years.

Although the strain in Texas was considered a low health threat to humans and different from the one blamed for the recent deaths of at least 22 people in Asia, officials could not rule out a risk.

A team of federal human and animal health experts went into action after weekend tests showed the Texas flock had a more virulent flu virus, known as H5N2, than a mild strain found this month in Pennsylvania, Delaware and New Jersey.

"Past experience with H5N2 viruses has indicated there is a low threat to public health," Dr. Nancy Cox of the Centers for Disease Control and Prevention said.

She said there were no known cases of the strain infecting humans, but said: "Nevertheless, as we move forward with this situation, we must keep an open mind and really monitor the situation as we go."

US animal health experts said consumers should not be concerned as bird flu cannot spread by eating poultry. Mild heating will kill the virus.

Ron DeHaven, a US agriculture department veterinarian, said there was "no epidemiological link" between the Texas infection and the Asian outbreak.

The Asian outbreak has alarmed scientists, who say it shows that a deadly strain of bird flu can jump species. Bangkok officials have also confirmed the deaths of two house cats from bird flu, the first domesticated mammals known to have contracted the disease in this outbreak.

The US agriculture department classified the flu strain found in Gonzales County, Texas, about 80 km east of San Antonio, as "highly pathogenic" to poultry and said it was "extremely infectious and fatal" to chickens.

The last time a highly pathogenic strain of bird flu was found in the US was in 1984, DeHaven said. More than 17 million birds were killed at a cost of nearly $65 million.

Shares in poultry companies, including the nation's largest poultry producer, Tyson Foods, fell in response to the Texas case. Tyson slipped US$0.46 to US$15.40 per share.

At the Chicago Mercantile Exchange, some cattle and hog futures prices were also lower amid concerns that bans on US poultry exports could cause a "meat glut."

Farmers fear bird flu because sick birds produce fewer eggs, which are often misshapen or soft-shelled. A mild form of the virus, commonly found in ducks and other migratory birds, is spread through the birds' feces or mouth secretions.