CHENGDU, China -- A highly infectious swine virus is sweeping China's pig population, driving up pork prices and spawning fears of a global pandemic among domesticated pigs. And animal virus experts say Chinese authorities are playing down the gravity and spread of the disease and refusing to cooperate with international scientists.
The mysterious virus - believed to be an unusually deadly form of an infection known as blue ear pig disease - has spread to 25 of the country's 33 provinces and regions, prompting a pork shortage and the strongest inflation in China in a decade.
More than that, China's past lack of transparency - particularly over what became of the SARS epidemic - has created global concern.
"They haven't really explained what this virus is," said Federico A. Zuckermann, a professor of immunology at the University of Illinois College of Veterinary Medicine. "This is like SARS. They haven't sent samples to any international body. This is really irresponsible of China. This thing could get out and affect everyone."
There are no clear indications that blue ear disease - if that is what this disease is - poses a threat to human health.
Though the Chinese government acknowledges that the current virus has decimated pig stocks in coastal and southern areas, it has not admitted what experts say is clear: The virus is rapidly moving inland and westward, to areas like this one in Sichuan province, China's largest pork-producing region.
"This disease is like a wind that swept in and passed from village to village," says Ding Shurong, a 45-year-old farmer who lost two-thirds of his pigs in a village near here. "I've never seen anything like it. No family was left untouched."
No one knows for sure how many of China's 500 million pigs have been infected. The government says officially that about 165,000 pigs have contracted the virus this year. But in a country that, on average, loses 25 million pigs a year to disease, few believe the figures. In part, the skepticism comes from the fact that pork prices have skyrocketed 85 percent in the past year - an increase that, absent other factors, suggests that losses from disease are more widespread than Beijing admits.
And there are other signs. Field experts are reporting widespread disease outbreaks. Fear among pig farmers that their livestock will contract the disease has triggered panic selling. And the government and news media here have issued alarming reports that farmers are selling diseased or infected pigs to illegal slaughterhouses, which could pose food safety problems. International health experts are calling this one of the worst disease outbreaks ever to hit Asia's livestock industry, and they fear that the rapidly mutating pathogens could spread to neighboring countries, igniting a worldwide epidemic that could affect pork supplies everywhere.
A similar virus has been detected in neighboring Vietnam and Myanmar, and health experts are trying to determine whether it came from China.
The Chinese government says it has reported the disease to international health bodies and insists the disease is under control and that a vaccine has been developed and distributed.
But, some scientists say there is no truly effective vaccine against blue ear pig disease (also known as porcine reproductive and respiratory syndrome); other experts say they are not even certain the virus gripping China is blue ear pig disease.
The U.N. Food & Agriculture Organization is pressing China to share its research and tissue samples.
China's Ministry of Agriculture declined to comment on what areas are most affected. Some government scientists called that information a state secret.
But it is not a secret here in Sichuan province, home to some 55 million pigs and one of the world's most densely populated pig breeding areas.
Here there is devastation. Many pig farmers say what appears to be blue ear pig virus swept through this region in June and July, killing thousands of pigs.
"First they refused to eat, then they got high fever," said Zhao Yanjun, 32, who lost all but five of his 150 pigs.