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E-M:/ cattle pharmaceuticals/ecological damage

for complete article: http://www.nytimes.com/2004/01/29/science/29VULT.html
NY Times/Science
January 29, 2004

A Drug Used for Cattle Is Said to Be Killing Vultures

A mysterious and precipitous plunge in the number of vultures in South Asia, which has pushed three species to the brink of extinction, is probably a result of inadvertent poisoning by a drug used widely in livestock to relieve fever and lameness, scientists reported yesterday.

Studies in Pakistan showed that the drug, diclofenac, an anti-inflammatory commonly prescribed for arthritis and pain in people, caused acute kidney failure in vultures when they ate the carcasses of animals that had recently been treated with it. The findings, which followed a two-year investigation by an international team of 13 scientists, were published online by the journal Nature.

Dr. J. Lindsay Oaks, an assistant professor of veterinary medicine at Washington State University who was the primary author of the report, said the devastation of vulture populations was the first clear case of major ecological damage caused by a pharmaceutical product.

There has been growing concern among scientists and environmentalists about the "vast amount of drugs that end up in the environment one way or another," he said, but no effect of this magnitude.

A study in 2002 by the United States Geological Survey found traces of many different pharmaceuticals and "personal care products" — including steroids, insect repellents and many others — in the American water supply. The effect of these traces is unknown, but the concern is about the unexpected. One laboratory study suggested, for example, that antidepressants like Prozac could trigger spawning in some shellfish.

The vulture finding in South Asia comes as a surprise: while environmental toxins had been suspected in the deaths, a pharmaceutical drug had not. Scientists in India and England suggested that disease was the cause of vulture deaths in India, but they found no infectious agent. The scientists who did the research in Pakistan said the situation in India was likely to be the same as that in Pakistan. But they said they did not have conclusive evidence.

Dr. Oaks said the investigation, which began in 2000, was prompted by reports of a 95 percent drop in the number of Asian white-backed vultures (Gyps bengalensis), Indian vultures (Gyps indicus) and slender-billed vultures (Gyps tenuirostris). All three are listed as critically endangered by the World Conservation Union, the international environmental agency based in Switzerland.

Thomas E. Lovejoy, president of the H. John Heinz III Center for Science, Economics and the Environment, who has long been a leader in environmental policy, said he thought the paper made a "watertight" case for diclofenac as the culprit in the vulture decline.

"I think what it actually says is that we really need to look systematically at the use of pharmaceuticals for veterinary purposes," Dr. Lovejoy said. He added, "It does raise a question of whether we should be looking more closely at the trace chemicals from human use."  ...