Meat and bone meal (MBM) may not be the cause of bovine spongiform encephalopathy (BSE) at all, according to Aquafeed.com, the aquaculture feed industry website. In an interview with Aquafeed.com, dairy farmer and BSE researcher Mark Purdey reasoned that MBM has been falsely accused, that the root cause lies with an organophosphate (OP) called Phosmet.
In the early days of the United Kingdom’s (UK’s) BSE epidemic, Purdey started to notice a strong correlation between the spread of the disease and the zones where warble fly eradication was taking place. In the UK only, a compulsory high dose treatment with Phosmet was being used in a new oil based formulation to treat cattle. This seemed a plausible candidate as OPs are toxic to the nervous system; research into the cellular affects of OPs was virtually non-existent and this was probably going to be a new mechanism; and it was poured onto the spine, only a few millimeters from the target organ. The warble fly campaign had started a few years prior to BSE in the zones where cows were getting BSE.
The official explanation for the disease is that scrapie prion in MBM had crossed the species barrier and “infected” cattle. It has been said that the mutant protein material had become pathogenic, due to certain relaxations in the European rendering procedures that had once inactivated it. Purdey has commented that this struck him as very naive as it didn’t fit the epidemiology and there was virtually no scientific evidence to support it. It was subsequently shown that these relaxations had no affect on the mutant prion.
“I thought BSE involved complex aetiology and pathology much closer to, say Alzheimer’s disease (AD), than to a simple infectious disease like TB or foot-and-mouth,” Purdey told Aquafeed.com. “I was convinced that the disease arose due to abnormal environmental exposures that involved oxidative stress, levels of specific trace metals, and their partner proteins [as in AD]. Infectious agents weren’t necessary. I was really the only person thinking this way at that time and – due to my position on pesticides – met with considerable opposition.”
Purdey claims the official MBM hypotheses of the UK Ministry of Agriculture and the Royal Society is unconvincing because of the amount of scientific contra evidence that exists. These are some of Purdue’s key objections:
• MBM fed to experimental animals does not produce transmissible spongiform encephalopathy;
• Thousands of tons of MBM exported abroad, when the mutant prion content was at its highest, did not produce any BSE;
• Mutant prion has been drastically reduced (to presumably nil) in MBM over the last 14 years and yet BSE has been starting, with a continued trend upwards, in a number of countries, i.e., Republic of Ireland, Portugal, Spain, Belgium, France, Switzerland, the Netherlands, Germany, and Italy;
• Scrapie material has been added to MBM and fed to cattle since the mid-nineteenth century without causing BSE;
• Changes in the processing of MBM (lowering temperature and the cessation of chemical extraction) often blamed for triggering BSE occurred in several other countries without causing BSE;
• Experiments showed that the original solvent extraction process with acetone could not breakdown mutant prion;
• Many cattle are now developing BSE in the UK and elsewhere without exposure to mutant prion either via feed or vertical exposure (via their parents);
• Scrapie strains inoculated into cattle brains do not produce BSE;
• Creutzfeldt-Jakob Disease (CJD) plaques are now being found in lifelong vegetarians; and
• Variant-CJD has not been transmitted experimentally by food products to which
humans were exposed.
Research for Purdey’s theory has recently received funding from the UK’s Ministry of Agriculture, Food, and Fisheries.
June 2001 Render