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Outbreak of Pig Disease in China


August 20, 2007; Page A4

HONG KONG -- International animal-health experts have flown to Vietnam to determine whether a new virus afflicting pigs in China has spread, rekindling tensions over China's cooperation in alerting the outside world to diseases within its borders.

The disease, which isn't a threat to humans but has infected millions of pigs in China, has been identified by Chinese scientists as a highly pathogenic variant of porcine reproductive and respiratory syndrome, also known as blue-ear disease because of the symptom infected piglets can show.

Chinese pork prices are up sharply, and blue-ear disease may be playing a role, though it isn't clear how big or what other factors may be at play. The disease was first discovered in the U.S. in 1987 and was found in Europe and Asia in the early 1990s, according to the Chinese researchers.

In June, 29 researchers -- almost all from China's top research centers, including the China Animal Disease Control Center in Beijing and the Chinese Academy of Sciences -- published a paper on the virus in PLoS ONE, a new online scientific journal published by the Public Library of Science, a nonprofit organization based in San Francisco. The paper examined a Chinese outbreak last summer that infected more than two million pigs, of which about 400,000 cases were fatal.

But some animal-health experts, both within and outside China, wonder whether the Chinese research team has the right diagnosis. Since blue-ear disease usually doesn't kill adult pigs, "it's very, very strange for us," says Juan Lubroth, head of infectious diseases at the United Nation's Food and Agriculture Organization. "For the Chinese to say this is the responsible agent for this killer virus, I think it could be a component" of a mix of pathogens, perhaps including a bacterial agent, a different virus or a combination of the two.

The uncertainty has again stoked worries that China may not be doing enough to cooperate with the outside world when it comes to diseases. In 2002 and 2003, the Chinese government initially tried to cover up the outbreak of severe acute respiratory syndrome, which eventually killed nearly 800 people world-wide.

Chinese scientists involved with the research say they have been forthcoming. "There is nothing secret," says George F. Gao, director general of the Institute of Microbiology at the Chinese Academy of Sciences in Beijing and one of the authors of the Chinese paper. Dr. Gao says that, if anything, the government has been pressuring the Chinese researchers to release the information they had.

The Agriculture Ministry in Beijing wasn't available for comment.

The uncertainty about the nature of the disease has prompted Vietnam to look into unusual pig deaths within its borders. Carolyn Benigno, animal health officer with the Food and Agriculture Organization in Bangkok, along with two other animal-health experts, have flown to Vietnam to investigate.

For the past week, they have been interviewing farmers and collecting virus samples, she says. The FAO sent one batch of virus samples last week to the U.S. Agriculture Department's animal-disease laboratory on Plum Island, N.Y., and will be sending a second batch shortly.

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