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[Day_Tripper]

http://www.mindfully.org/Farm/Mad-Cow-Mark-Purdey.htm

Mad Cow Disease Theory Challenged by Mark Purdey
Penny Fannin / The Age (Australia) 24apr01

[Solidarity: Mad cows and an Englishman BBC  25mar01]
[Interview with Mark Purdey BBC 25mar01]

An amateur British scientist's belief that mad cow disease is caused by cattle being exposed to the metal manganese and a common insecticide has gained acceptance from members of Britain's scientific community.

Mark Purdey, an organic farmer, has spent 15 years collecting evidence that the British Government's explanation for bovine spongiform encephalopathy (BSE) - that it is caused by animals being fed infected meat and bone meal from sheep infected with scrapie - is wrong.

It is widely believed that variant Creutzfeldt Jakob Disease - the human form of mad cow disease - is caused by eating BSE-infected beef. But Mr Purdey believes high levels of manganese in the environment and exposure to the pesticide phosmet don't just affect cows, but also make people susceptible to CJD.

His findings were detailed in a BBC Panorama special on the ABC's Four Corners last night.

David Brown, a CJD researcher at Cambridge University, believes Mr Purdey's theory has merit. "I think the general view of what caused BSE is wrong," he told Panorama.

When BSE was identified in 1986, Mr Purdey noticed that areas where the disease was emerging broadly corresponded with those where organophosphate pesticides such as phosmet had been used against the pest warble fly.

In experiments, Mr Purdey and Dr Stephen Whatley at the Institute of Psychiatry found that phosmet increased the number of prions - proteins produced in human and animal brains. Usually, prions exist for a few hours but in diseases like BSE they become almost indestructible, building up in brain cells until the cells die.

Mr Purdey believes these higher prion numbers, coupled with increased manganese in the environment, could cause BSE. He studied the environment in so-called cluster areas of spongiform encephalopathies, including Colorado and Iceland. In each he found high levels of manganese and low levels of copper.

Dr Brown found that prions starved of copper and dosed with manganese change their shape to the dangerous form of the prion.

Dr Steven Collins, coordinator of Australia's CJD case registry, said Mr Purdey's ideas were known but had not gained wide acceptance.

He said they needed to explain why outbreaks were recorded among zoo animals that were fed protein and meat meal. "He has to have a whole explanation. It has to cover all dimensions of the epidemic. Why has the epidemic diminished? Has there been a change in pesticide use or manganese levels?"