China reported five more areas with suspected cases of the deadly bird flu virus in poultry on Sunday, bringing to 11 the total number of such outbreaks in eight provinces.

Ten out of 33 regions in the world's most populous nation have confirmed or suspected outbreaks of the avian influenza, which has spread to 10 Asian countries and killed at least 10 people in Vietnam and Thailand.

Chinese authorities have closed down poultry processing factories in three provinces where outbreaks have been confirmed – Hubei, nearby Hunan and southern Guangxi, the official Xinhua news agency said.

Chinese authorities have been culling poultry within three km (two miles) of infected farms, vaccinating birds within five km (three miles) and established a national command headquarters to battle the disease.

Authorities have banned poultry exports from six of the bird flu-hit provinces and stepped up sanitation checks at markets.

Controlling outbreaks in China is worrisome to health experts because nearly four out of five fowl are raised on household farms, where peasants live close to their animals.

The World Health Organization warned on Friday that China's window of opportunity to stop the spread of bird flu was narrowing.

Editors note: Richard Brock, The Corn and Soybean Digest's Marketing Editor, is president of Brock Associates, a farm market advisory firm, and publisher of The Brock Report.

To see more market perspectives, visit Brock's Web site at www.brockreport.com.