Bird flu (search) reached China, the world's most populous nation, as officials acknowledged Tuesday that at least one duck was infected with the disease and opened an investigation into suspect cases of other dead poultry.

The announcement opened a potentially fearsome new front in the fight against the virus that now has appeared in 10 Asian nations.

Vietnam reported Wednesday that two more people died as a result of bird flu, bringing the total number of deaths in the region to 10. Officials had earlier confirmed six deaths in Vietnam and two in Thailand.

In Atlanta, the head of the U.S. Centers for Disease Control and Prevention (search) urged American doctors to test patients with flu-like symptoms if they had recently been to areas with bird flu outbreaks.

Asian countries ravaged by bird flu sent ministers to Bangkok for an emergency meeting Wednesday on how to keep the virus from becoming a global pandemic. The United States and European Union also sent representatives.

China's announcement also created unease about the food supply for Chinese still shaken by last year's SARS (search) outbreak. Chicken is No. 2 only to pork as a staple meat for China's 1.3 billion people. Japan immediately suspended chicken imports from China, its third-largest supplier of chicken meat and products.

The cases involved ducks in the southern region of Guangxi, on a farm 60 miles from the border with Vietnam, where avian influenza has killed six people. Two people have died in Thailand, and tens of millions of birds have been slaughtered. Nearby Laos also reported its first cases in birds on Tuesday.

Chinese authorities isolated the area around the farm, in a town called Dingdang. Some 14,000 birds within a two-mile radius were slaughtered, and poultry for three miles around was quarantined, the government said.

"Local governments have made necessary measures of slaughter or quarantine to prevent a spread," the official Xinhua News Agency said. "No people have been found infected so far and the epidemic has been in control."

What authorities don't know is significant as well: how and where the birds were infected. Animal smuggling is common in Guangxi; last week, piglets spirited in from Vietnam were burned in their cages by quarantine officials. International health officials also say they believe the virus could be spread by migratory birds.

Xinhua also said reports of bird deaths in a "chicken-raising household" in central Hubei province and a "duck-raising household" in nearby Hunan province had been diagnosed as "suspect" bird flu. It emphasized those diagnoses were preliminary.

The type of avian influenza in much of the current Asian outbreak is fearsome for two reasons -- its virulence and the possibility it could mutate into something that can jump from human to human. Thus far, the only known transmissions to humans have been from birds.

The World Health Organization said Tuesday there was a good chance of keeping the disease from taking root in the human population. Dr. Klaus Stohr, the agency's project leader for influenza surveillance, said he was encouraged by the relatively small number of human cases, even though the virus may have been circulating in birds for some time and humans have been exposed to it.

"We have a window of opportunity to deal with this disease," said Stohr. "We have a good chance of controlling this."

The head of the CDC, Dr. Julie Gerberding said anyone with flu-like symptoms who has been to affected countries should be tested for the virus.

"It appears to be very unlikely [that they would have the disease], but we want to be very vigilant," Gerberding said.

She also urged people who travel to areas with outbreaks to stay away from poultry, live animal markets and any surfaces contaminated with bird droppings.

In Thailand, officials confirmed that a 6-year-old boy died of the disease, the country's second known flu death. Eight people have died in Vietnam, where the fast-food chain KFC said it would offer its customers fish instead of fried chicken.

So far, 10 governments have reported some strain of bird flu -- Cambodia, China, Indonesia, Japan, Laos, Pakistan, South Korea, Taiwan, Thailand and Vietnam.

As protective chicken slaughters increased, the World Health Organization warned workers to don protective clothing and masks. Bob Dietz, a WHO spokesman in Hanoi, said it "wouldn't be surprising" that bird flu could travel across the border into China.

China's openly aggressive campaign to combat the disease starkly contrasts with the government's initial secretive response to SARS. Severe acute respiratory syndrome killed 774 people worldwide, including 349 people on the mainland, before retreating last June.

On Tuesday, after the confirmed case of bird flu, Agriculture Ministry spokesman Jia Youling vowed to "strengthen monitoring and increase international cooperation to prevent further spread." WHO spokesman Roy Wadia in Beijing said the Health Ministry had informed his agency.

Still, there were contradictions in the government's account. While Xinhua said anti-flu efforts had been going on at the duck farm since Friday, Yan Qibin, an official with the Food Quarantine Bureau, said Tuesday that his agency was investigating whether any ducks had actually died there.

Also Tuesday, other Chinese quarantine officials said they would impose poultry bans on Pakistan and Indonesia, bringing to eight the number of countries whose bird products have been banned from the region's largest economy.

Australia, which remains free of the virus, urged other countries to quickly reveal bird flu cases, following allegations Thailand and Indonesia initially covered up outbreaks.

"Countries in the region must learn from the SARS experience, and that is: 'fess up as soon as you find a case, as quickly as possible,'" Australian Foreign Minister Alexander Downer told Australian Broadcasting Corp. radio. "Make sure everybody knows about it and deal with it."