Mad Sheep Scare
East Warren, Vermont
Oblivious to an international controversy and a death sentence, 120 sheep dotted the hillside of Larry and Linda Faillace's farm. Miles away in a courtroom in Brattleboro, Vermont, a federal judge ruled August 1 that the animals should be slaughtered because they might have mad cow disease.
After years of dismissing suggestions that mad cow disease might threaten U.S. livestock, the U.S. Department of Agriculture used controversial tests to claim these sheep, imported to Vermont from Belgium in 1996, may harbor the always fatal transmissible spongiform encephalopathy, or TSE, that has killed or infected more than 70 Britons and devastated that country's beef industry.
On July 14, Agriculture Secretary Dan Glickman issued a "Declaration of Extraordinary Emergency" charging that four sheep, culled from one of three suspect Vermont flocks, had tested positive for an "atypical TSE of foreign origin." He ordered the immediate seizure and destruction of 376 sheep.
The USDA order sparked an unprecedented court hearing and heated scientific debate. At issue is whether the sheep had ordinary scrapie, a TSE endemic to the United States and presumed harmless to humans; some atypical scrapie; or whether, as the USDA suggests, they may be the first sheep in the world documented to have mad cow disease. There is also the possibility that the official tests are flawed, the sheep are healthy, and the main threat they pose is to the peace of mind of USDA officials. Linda Detwiler, the USDA's lead veterinarian on TSE issues, who has been tracking the sheep for years, insists that even if the risk is small, it is just not worth taking.
Belgium, however, believes that the USDA is acting precipitously. And on August 4, formally asked the USDA to return all of the sheep alive. The Vermont owners volunteered to pay transport costs. "The USDA repeatedly refused European requests for tissue samples," says Belgian veterinarian Bernard Carton, who oversaw the export of the sheep to the United States. "This is not just an American issue. If the USDA is right, the whole European sheep industry is at risk."
TSE is a family of diseases caused by rogue proteins, called prions, that create sponge-like holes in the brain, leading to dementia and inevitably death. The TSE for sheep is called scrapie; for cows, it's mad cow or bovine spongiform encephalopathy; and in humans, where the incubation period for the disease can last decades, it's Creutzfeldt-Jakob disease. Although mad cow is the only TSE that has been shown to jump species and infect humans - as happened in Great Britain, other TSEs have been passed among species in the laboratory through intensive exposure. Thus, the possibility that sheep could contract mad cow and spread it to humans cannot be ruled out.
In 1998, after discovering that the Vermont sheep might have eaten mad-cow-contaminated feed in Belgium, the USDA quarantined the flocks and began testing brain matter from culled animals. (There is no reliable TSE test for live animals.) A few sheep had already been eaten.
Then this summer, a few blood samples sent to the USDA's National Animal Disease Center in Ames, Iowa, came up positive for TSE. The USDA sent brain samples, a more accepted determinant, to Richard Rubenstein of the Institute for Basic Research in Developmental Disabilities in Staten Island, New York. After he too reported TSE-positive test results, the USDA issued the kill order.
While one Lydonville, Vermont owner voluntarily sold his 21-sheep flock to the government, the Faillaces and Houghton Freeman, who owns the largest flock, asked the court to intervene. The owners argued that the sheep-valued by cheese-makers for their extraordinary milk production - were never fed suspect European feed, the test methodology was fatally flawed, and the results were dead wrong.
USDA lawyers were taken aback when Vermont Judge J. Garvan Murtha agreed to hear the case. It was the first time ever, according to USDA lawyer Tom Bundy, "that an order to dispose of animals under an order of extraordinary emergency has been challenged in court."
At the July 28 hearing, in a packed courtroom in Brattleboro, the fate of the sheep hinged on whether the two eminent scientists testifying for the sheep farmers could cast doubt on Rubenstein's tests. Critics charge that his methodology tends to yield false positives. Testifying for the sheep owners, Glenn Telling of the University of Kentucky called the results "inconclusive" and pointed out anomalies in Rubenstein's tests and lack of negative controls. "If it was my lab and I got these results," he said. "I would suggest that each test be repeated."
But since all the brain matter had been used up, retesting the same sheep was no longer an option. "If the USDA had half a brain," quipped Thomas Higgins, a lawyer for the sheep farmers, "we could all get this over with."
What the USDA did have during the hearing were blood samples from the sheep surrendered by the Lydonville owner and slaughtered on July 21. The samples were sent to the USDA's Iowa lab, but the results (and even the fact that the tests were undertaken) were never made public. The lab processed blood from the 21 sheep to the point where it could get results, and then the USDA impounded the samples. "It's obvious to me that they don't want to know the answer and lack confidence in the evidence they presented in court," says Larry Faillace.
Rubenstein, testifying for the USDA in Brattleboro, said he was "absolutely confident" of his results. "If I had any doubt," he said. "I would not say the sheep are positive."
But even if he is right, the question remains: Positive for what? After hours of mind-numbingly technical testimony, one thing was clear: Scientists on both sides refused to support the government's provocative claim that Rubenstein's tests could determine if the TSE was "atypical" or "of foreign origin," much less differentiate between mad cow disease and scrapie. The only test which can make that diagnosis takes eight months to two years for the results. "The only thing you could possibly conclude [from Rubenstein's tests] is that the sheep might have scrapie, a disease currently endemic to the United States," Higgins says. "From that, the USDA has taken a huge scientific leap. ... If they can do that, they can seize every sheep flock in the country."
That idea may not be as far-fetched as it seems. Stanley Prusiner, the Nobel laureate who first identified prions, and his colleague Mike Scott worry that too little is known about scrapie and its relationship to mad cow disease. "The assumption is that because sheep scrapie has been around so long, it poses no threat," Scott says. "But it's kind of like an unexploded bomb ... since it is a source of prions."
Stressing that the hypothesis is unproven, the two scientists suspect that British cows may have gotten mad cow disease from eating the rendered carcasses of sheep infected with both scrapie and mad cow prions. The rendering process may have destroyed normal and scrapie prions, while allowing mad cow prions to survive. "Lurking out there in small numbers in any sheep may be the [mad cow] prion and under the right circumstances, [it] emerges," Prusiner recently told New Scientist magazine.
Questions of the accuracy of the test aside, in the Vermont case the USDA ignored its own protocol for dealing with TSEs. When sheep are diagnosed with scrapie, the department kills individual exposed and infected animals but spares the flock. If mad cow is ever diagnosed in the United States, the USDA is supposed to implement its 1998 emergency response plan, under which a "pathologist will hand-carry the sample to the United Kingdom for confirmation ... [within] 24 to 96 hours." The government would then eradicate the whole herd.
But despite irregularities and lingering questions, Judge Murtha ruled that the sheep should be killed since "both flocks have suffered a potential exposure to TSE ... [and] if the secretary is correct that the continued presence in the country of the Belgian sheep constitutes an unacceptable risk, their destruction will greatly reduce the possibility that humans and domestic animals will be exposed to a contagion not currently endemic in the United States." (The farmers have filed an appeal.)
If (and that is a big if) post-mortem testing reveals that the animals did indeed have mad cow disease, the economic and health consequences may be relatively minor for the United States (presuming the outbreak has been controlled). The implications for Europe, however, are staggering. If the Vermont sheep were infected in Belgium by mad-cow-contaminated feed, innumerable other sheep throughout Europe were similarly exposed. Also of concern to Europe is the July 18 recommendation by the Vermont Health Department that as a "health precaution" people not eat cheese from the Vermont flocks. Scott calls the announcement "a bit of panic-mongering." "If they reckon there is a risk from Vermont cheese," he adds, "Europe is exposed to the same risk. But I don't believe there is any evidence that people can acquire TSEs through eating dairy products."
The day before the Vermont "recommendation," Detwiler, the USDA veterinarian, had told the New York Times that there was little need to worry about the cheese. Higgins, an attorney for the sheep owners, explained the discrepancy by saying Vermont's warning "wasn't about public health, it was a pressure tactic to get the farmers to give up their sheep" by ruining their business.
But the USDA is tasked with protecting not only human and animal health, but the economic health of the U.S. meat industry. Its emergency declaration described the Vermont situation as "a real danger to the national economy and a potential serious burden on interstate and foreign commerce." Aware that a mad cow scare in the United States could be devastating to livestock exports, says John Stauber, co-author of Mad Cow USA, "the USDA is desperately trying to send a message to the world and to U.S. consumers that 'we don't have it here.' "
Stauber is skeptical because time and again - in the cases of hormones in beef and milk, dioxin and pesticides in food, genetically engineered crops and global warming - when the science is ambiguous, the government sides with industry. Insisting it relies on "sound science" while Europeans resort to "hysteria," Washington assumes safety until it has incontrovertible proof of danger. "Its failure to address U.S. sheep scrapie and mad deer and elk disease [which is endemic to several Western states] is pure and deadly hypocrisy," Stauber says. "The USDA is engaging in 'big lie' tactics to protect the export image of the U.S. livestock industry."
Yet in her affidavit filed in the Vermont case, Detwiler argues that "when preventing diseases with extremely long incubation periods and no means of detection until signs of the disease are evident, one is usually years if not a decade late when acting in response. ... We do not want to repeat the mistakes of the past."
It remains to be seen if they already have.
Terry J. Allen is a contributing editor of n These Times.