BEIJING -- Bird flu 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.
In Atlanta, the head of the U.S. Centers for Disease Control and Prevention 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 today 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 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 birds for three miles around were quarantined, the government said.
"We're seeing it in other countries in southeast Asia," Dietz said. "There's no reason to assume China would be immune."
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 that those diagnoses were preliminary.
China's openly aggressive campaign to combat the disease starkly contrasts with the government's initially secretive response last year to the SARS outbreak. Severe acute respiratory syndrome killed 349 people on the mainland before retreating in June.
Still, there were contradictions in the government's account. Xinhua said anti-flu efforts were going on at the duck farm since Friday, but Yan Qibin, an official with the Food Quarantine Bureau of the Ministry of Agriculture, said Tuesday his agency was investigating whether any ducks 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.
China stopped such shipments from Cambodia, Thailand, Japan, South Korea and Vietnam in an effort to prevent the disease from spreading to its poultry.
Laos and Taiwan also have reported the virus but the mainland has not mentioned poultry bans from those areas.
In Thailand, the Public Health Ministry confirmed that a 6-year-old boy died from the disease Tuesday, becoming the country's second fatality and the region's eighth. Thai officials awaited lab results on five other deaths believed linked to the virus, meaning the toll could reach 13.
Thailand's first death, announced Monday, also was a 6-year-old boy, who carried a dying chicken to a butcher.
In Laos, a sample taken from a chicken farm near the capital, Vientiane, tested positive for the disease, said Singkham Phounvisay, director general of the country's Livestock Department.
The tests were conducted after hundreds of chickens died. The results were known Monday, but the exact strain of the virus has not been identified, he said.
Agriculture Ministry officials were expected to begin slaughtering about 3,000 chickens at a farm on the capital's outskirts Tuesday. The carcasses then would be burned.
A joint document circulated at a meeting of Laotian government and U.N. representatives last week said chicken farms in other parts of the country had been hit by the disease.
The scope of this year's outbreak has widened alarmingly, with countries reporting new outbreaks in poultry stocks over the past three days.
The other nations reporting some strain of bird flu include Cambodia, Indonesia, Japan, Pakistan, South Korea and Taiwan. Some countries claim their version of bird flu is milder than the one that has jumped to humans.
Pakistan said strains of the disease killed millions of chickens but had not infected humans.
"We are safe," Pakistan Health Minister Mohammed Nasir Khan said Tuesday. "There is right now no need to panic in Pakistan."
Tens of millions of poultry across Asia have been infected in recent weeks, prompting mass slaughters of chickens at farms to contain the virus. South Korea alone has killed 24 million chickens and ducks.
WHO said the virus has mutated since an outbreak in Hong Kong in 1997, when six people were killed in the first documented case of the virus jumping to humans and the deadliest episode until this year's outbreak.
The mutations complicate the search for a vaccine. The virus strain isolated from the 1997 outbreak can no longer be used to produce the medicine, WHO said.
Scientists believe people get the disease through contact with sick birds. Although there has been no evidence of human-to-human transmission in the latest outbreak, health officials are concerned the disease might mutate further and link with regular influenza to create a form that could trigger the next human flu pandemic.