China on Thursday reported its sixth human case of bird flu and a new outbreak in a flock of ducks.

The latest human infection is a 35-year-old man in Suichuan County in the eastern province of Jiangxi, the official Xinhua News Agency said, citing a Health Ministry statement. It didn't give any other details.

China has reported two confirmed human deaths from bird flu and a suspected case in a 12-year-old girl who died.

Also Thursday, China reported a new bird flu outbreak on a poultry farm in the village of Shangxi, also in Jiangxi. It said 1,640 ducks were dead and 15,000 birds in the surrounding area were destroyed to stop the outbreak.

The government statements didn't say whether the two cases in Jiangxi were believed to be linked.

The newly reported cases were a setback for official efforts to contain the disease after the government said Wednesday that China had no new cases for the past 15 days.

The country's top veterinary official warned that China should brace itself for new outbreaks in the winter and spring. He said the Lunar New Year holiday in January will raise the risk of the disease spreading because millions of people will travel and there will be an upsurge in poultry shipments to supply family banquets.

The virulent H5N1 strain of bird flu has killed at least 71 people in Asia since 2003, mostly through contact with infected birds.

Experts say repeated outbreaks in poultry are increasing the risk that the virus could mutate into a form that can spread easily between people, sparking a global pandemic that could kill millions.

China has mounted an aggressive campaign to fight bird flu.

It is in sharp contrast to the initial secrecy authorities used to handle an outbreak of severe acute respiratory syndrome — or SARS — which emerged in Guangdong province in 2002.

Authorities have reported 25 bird flu outbreaks in poultry around China since Oct. 19. The government says 151,000 chickens, ducks and geese have died and another 22 million were destroyed to stop the outbreaks.

The government says it has nearly completed a campaign to vaccinate all of China's 5.2 billion domesticated birds against the virus.