Health officials appear to have successfully contained a bird flu outbreak in southwest China's Tibet after slaughtering almost 7,000 chickens.

The regional government launched an emergency plan after dead poultry from a market in the capital city, Lhasa, tested positive for H5 bird flu virus.

Officials moved to curb the spread of the disease after reports that 680 chickens died on Thursday, said Cai Bing, an official with the regional agriculture and husbandry department.

Samples of the dead poultry were tested in the regional center for animal epidemic and disease prevention and control, Cai said. The results were confirmed by the National Avian Influenza Reference Laboratory.

The market had two poultry vendors who had transported 8,100 chickens from other provinces on Feb. 27, including 430 sold to other markets in Lhasa before the infection was discovered, said Cai.

Regional authorities had the remaining 6,990 chickens slaughtered. The market has been ordered to remain closed for six months.

Measures such as disinfection of the area near the market and inspections of poultry markets had been adopted, said Cai.

Ministry of Agriculture experts have arrived in Lhasa to inspect the poultry markets and praised the local government's timely and effective culling.

The source of the infected chickens was still under investigation, said Cai, adding authorities were also tracing the 430 chickens sold to other markets.

Ninety-one people who had close contact with the chickens, including the two vendors and nearby residents, had been put under medical observation, Cai said.

Sales of live birds in markets within a 13-kilometer radius of the market have been banned. Poultry transported to Tibet since Friday were required to undergo observation and quarantine before going to market, said Cai.

Although most of the vendors are still doing business, the sudden outbreak has cost them heavily.

"Normally I sell more than 20 chickens a day, but I have only sold six since March 1 when the bird flu was reported in Lhasa." said Shao Jiangang, a vendor in Balin market, 13 kilometers from the quarantine area.

Earlier this month three wild birds and two poultry birds tested positive for the H5 virus out of 325 poultry and 20 wild birds tested in Fujian Province, where a woman who contracted the disease late last month is in a critical condition in hospital, according to authorities.

(Xinhua News Agency March 8, 2007)