China has reported its third major outbreak of bird flu in two weeks.
There are fears of further outbreaks in China
Officials said 545 chickens and ducks died of the virus in a village in the central Hunan province, and almost 2,500 had been killed as a precaution.
Earlier outbreaks hit Inner Mongolia and Anhui provinces, but so far China has seen no human bird flu deaths.
Meanwhile, a conference of health ministers in Canada has called for more research to find a vaccine to protect people against bird flu.
The US Secretary of Health, Michael Leavitt, told the Ottawa conference that politicians had to find a balance between informing and inflaming.
Some countries, including Canada, had supported a Mexican proposal to increase manufacturing capacity both for anti-viral drugs and any future vaccine, reports the BBC's Lee Carter.
H5N1 BIRD FLU VIRUS
Principally an avian disease, first seen in humans in Hong Kong in 1997
Almost all human cases thought to be contracted from birds
Possible cases of human-to-human transmission in Hong Kong, Thailand and Vietnam, but none confirmed
This could be achieved by transferring manufacturing to countries such as Mexico, Brazil or India, where production could be increased while costs could be kept down.
In another development, the European Union has announced a ban on live wild bird imports to any of its 25 member-states.
Fears of infection arriving among pet birds have risen after a parrot died of the H5N1 strain - potentially deadly to humans - while in quarantine in the UK.
Nearly 250,000 such birds have been imported into the EU for pet shops and collectors in the past three months, but the trade will now be halted for at least a month. The ban will be reviewed in November.
On Tuesday, the death of a fourth Indonesian from bird flu was confirmed in Bogor, near the capital, Jakarta.
The H5N1 strain has killed at least 60 people in Asia since 2003.
The latest outbreak occurred in the village of Wantang, the Chinese agriculture ministry said in a report to the Paris-based World Organisation for Animal Health.
The report said the deadly H5N1 strain of virus was detected in poultry last Saturday and confirmed on Tuesday.
An outbreak last week killed some 2,600 chickens and ducks in China's northern region of Inner Mongolia.
Several days later, 550 geese were killed in the eastern Anhui province.
China has recently activated a nationwide disease-reporting network, ordering local officials to plan for emergency measures, the state-run Xinhua news agency reported.
The government is also considering stockpiling anti-flu drugs.
But the World Health Organization says bird flu is endemic in poultry in China, the BBC's Daniel Griffith in Beijing reports.
Fighting this disease in such a vast country is going to be a tough challenge for the authorities, our correspondent says.
BIRD FLU OUTBREAKS IN 2005 (H5N1 STRAIN)
The H5N1 strain remained largely in South-East Asia until this summer, when Russia and Kazakhstan both reported outbreaks
Scientists fear it may be carried by migrating birds to Europe and Africa but say it is hard to prove a direct link with bird migration
EU has banned the import of captive live birds