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The 50-month-old dairy cow dairy cow found on a farm in
Alberta evidently showed prion development months earlier
than could have been expected, according to the Canadian
Food Inspection Agency report on its investigation of the
case.
"The staining pattern from the confirmatory IHC tests supported
the notion that this animal seemed to have been detected
at an earlier stage of BSE incubation," the report states.
"Had the animal succumbed to BSE and not to an unrelated
disease, it may have been some time before BSE symptoms
would have been noted."
USDA and other experts have contended that prion formation
dangerous to humans takes place only shortly before the
onset of BSE symptoms, and USDA has concentrated until very
recently on animals exhibiting symptoms of BSE and elderly
cattle most likely to have the disease.
Other experts, such as Michael Hansen of Consumers Union,
have argued that infectivity could be present much longer
before the onset of symptoms.
Bill Bullard, chief executive of Ranchers-Cattlemen Action
Legal Fund, charges that the discovery upsets the apple
cart of traditional scientific thinking about the disease.
"The revelation that a rapid BSE test can detect infected
animals up to eight months before the animal would have
fit the criteria for targeted testing is not only new news,
but groundbreaking news," he said in a statement.
CFIA, in its introduction to its report, downplayed that
possibility, saying that the variance of when BSE was detected
compared to when it was expected to be detected "is not
significantly different from that of previous cases and
indicates exposure to only a very low dose of BSE infectivity."
The animal died of complications due to mastitis, a disease
of the udder in cattle.
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