Vermont Sheep Mad Cow
'No Threat' To Humans...
But Don't Eat The Cheese!
From: Patricia Doyle <>
From: ProMED-mail <
From: Marjorie P. Pollack <> &
Lynn Caporale <>
Source: Boston Globe online (7-18-00)
The Vermont State Health Department on Tuesday recommended people not eat cheese made with milk from 3 flocks of sheep officials fear could be infected with the sheep version of mad cow disease (Bovine Spongiform Encephalopathy, BSE).
Health Commissioner Dr. Jan Carney said she made the recommendation after discussing the matter with the Centers for Disease Control and Prevention in Atlanta (CDC). "This is in the tone of a recommendation," Carney said. "There is no national or state recall. CDC considers the risk theoretical."
Carney said there were no known cases of people contracting the always-fatal BSE from milk or milk products like cheese. But the disease, which causes the brain to waste away, has a long incubation period and it is best to err on the side of protecting the public health, she said.
The cheese was from 2 plants whose products are distributed to specialty stores throughout the United States. The farmers who produce the cheese are contesting the federal government's efforts to have their sheep destroyed.
The plants manufacturing the cheese are Three Shepherds of the Mad River Valley, plant number 50-50, and Northeast Kingdom Sheep Milk Cheese, plant, 50-45.
The furor over the sheep flocks arose after tests done several weeks ago on the carcasses of 4 sheep found evidence of disease in their brains. Officials fear the animals were infected with a sheep version of BSE.
The results don't mean the animals had the same disease that killed about 50 people in Great Britain and devastated that country's beef industry, but they could have. [This would be the first case of sheep acquiring this disease other than experimentally. - Mod.TG]
[An] East Warren farmer, who produces the Three Shepherds cheese, said his cheese was safe. He and his wife are contesting the federal government's efforts to have their sheep destroyed; he says there is no evidence his sheep are sick.
Meanwhile, the owner of a Craftsbury flock of 230 sheep scheduled to be destroyed on Friday, said he planned to go to federal court to ask a judge for an injunction to block the slaughter of his sheep. [His] lawyer said Tuesday he expected to file the papers Wednesday.
The East Friesian sheep, which produce 10 times as much milk as sheep available in North America, were imported from Belgium in 1996 to start a sheep cheese business.
But the sheep came from an area of Europe where BSE is known to have occurred [in cattle] and federal officials fear they [the sheep] could have eaten contaminated feed. [This is not clear if they fear the possibly contaminated feed was fed to these animals while in the US, or if it was fed prior to importation into the US - Mod.TG] Last week Agriculture Secretary Dan Glickman ordered the sheep destroyed as a precautionary measure to ensure BSE doesn't make it into the United States.
[The Craftsbury farmer] said appraisers visited his farm Tuesday to determine the fair market value to pay him for the sheep slated to be taken away and destroyed Friday. [The other farmer] said the appraisers were due at his farm Wednesday.
****** [2] Date: Thu, 20 Jul 2000 05:24:22 -0400 From: Eleanor Kellon <
Clarification please. Isn't BSE now a problem for the whole EU - at least France and Belgium in addition to England? Isn't it true that BSE has the potential to effect any mammal and can be transmitted from consumption of any body part, not just brain? Are there tests available that can differentiate between BSE and scrapie? Are they proven to be different diseases or just assumed to be?
Why were these sheep permitted into the country in the first place? If this was an importation allowed before it was known Belgium had a BSE problem, why were they allowed to continue to sell cheese made from their milk? The European experience should have dictated more caution.
-- Eleanor Kellon, VMD
[Eleanor, BSE is a problem for the EU. Remember BSE is Bovine Spongiform Encephalopathy. It has not been identified in sheep, only in cattle. It has been experimentally produced in sheep, but there are no documented cases of naturally occurring cases. BSE is generally transmitted from neurological tissue. However, because of the method of killing cattle there is the risk of spreading microscopic particles of neurological tissue through the blood stream, thus infecting muscle tissue, which is most often consumed by human beings.
There are tests capable of differentiating BSE and Scrapie. One of those tests, I think, is the monoclonal antibody tests use on the third eyelid of the sheep. It is my understanding the USDA did not use this test. The most reliable test is injecting brain tissue into mice, then waiting several months for results. This test was not used by USDA. Hence, there is room to question the validity of tests. I think there are some other tests, but I am not positive.
Scrapie and BSE are different diseases. BSE may have originated from feeding scrapie infected sheep to cattle. But the rendering process and subsequent feed processes of temperatures and pressures resulted in a change in the prion organism. They are different diseases.
The sheep were imported in 1996. I don't believe Belgium had BSE then. Since BSE has not been identified in sheep, and Belgium had not had BSE, there appeared to be no risk with regard to importing the sheep. There have been no cases of the human form of BSE, new variant Cruezfeld-Jakob's Disease (nvCJD) being transmitted from milk. There are no cases of scrapie being transmitted from milk. They were permitted to sell the milk and cheeses because there is no risk of transmitting the disease through milk or milk products. - Mod.TG]
***** [3] Date: 20 July 2000 From: Tim Sly < Source: New Scientist, 22 Jul 2000
Claims that abnormal prion proteins have been found in American sheep are setting alarm bells ringing in the US. But [some] BSE experts are unimpressed.
The US government ordered the incineration of 376 sheep from Vermont, after suggestions 4 of the flock were infected with BSE-the brain disease in cows causing deadly new variant CJD (vCJD) in people. If the 4 cases are confirmed as BSE, they will be the first sheep known to be infected by farm feed, and would raise the specter of more human infection.
[A Vermont farmer] imported Belgian and Dutch milking sheep to his farm in 1996. The US Department of Agriculture (USDA), fearing the imported sheep could have eaten Belgian feed contaminated with BSE, tested animals culled from [the] flock for prion disease. This month it announced test results indicating 7 of the sheep had brain damage of the type associated with prion disease. The animals had not shown symptoms of brain disease.
Sheep brains can be damaged in this way by both BSE and scrapie-a prion disease affecting sheep but is not thought to harm humans. Antibodies used to test the sheep for scrapie did not bind to the brains of these sheep, however. Yet 4 came up positive for prions in 2 other tests: a new assay developed by Mary Jo Schmerr of the USDA laboratory in Ames, Iowa, and a Western blot analysis by Richard Rubenstein of the Institute for Basic Research in Developmental Disabilities, Staten Island.
On 14 Jul 2000, this led US agriculture secretary Dan Glickman to order the animals to be destroyed because they had prion disease "of foreign origin", which might be BSE.
Sheep deliberately fed BSE-contaminated feed will develop prion disease. While no one has ever shown this happens on farms, some scientists say it's possible BSE has appeared in sheep only to be mistaken for scrapie.
However, many experts doubt whether the Vermont sheep have BSE. "The connection to BSE is far-fetched speculation," says Tom Pringle of the Sperling Foundation in Oregon, which monitors prion research. The 2 tests used gave inconsistent results, and the imported animals were supposed to have been strictly grass-fed.
Scrapie and BSE can only be reliably distinguished by injecting brain tissue into mice, then waiting months for the result. Ian McConnell of Cambridge University, an adviser to the British government on vCJD/BSE, told New Scientist: "I have no idea how they would make this distinction. It's a shambles."
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