So far the virus, believed to be an unusually deadly form of an infection known as blue-ear pig disease, has spread to 25 of this country's 33 provinces and regions.

The government in Beijing acknowledged that in the past year, the virus had decimated pig stocks in southern and coastal areas. But animal virus experts said that the Chinese authorities were playing down the gravity and spread of the outbreak, and had refused to cooperate with international scientists.

Experts said the virus was rapidly moving from the coasts to inland and the west, to areas such as Sichuan Province, China's largest pork producing region. The situation is grave because China consumes half the world's pork and considers pork its primary source of protein.

It is not known how many of the country's 500 million pigs have been infected by the virus. But the resulting pork shortage has helped fuel the strongest inflation in China in a decade, and even set off panic selling of pigs by farmers worried that they will suffer severe losses if their livestock contract the disease.

The government in Beijing said that about 165,000 pigs had contracted the virus this year. But in a country that, on average, loses 25 million pigs a year to disease, few believe the figures, particularly when pork prices have skyrocketed by more than 85 percent in the past year and field experts are reporting widespread disease outbreaks.