Ministry is accused over cause of 'mad' cows: Officials study farmer's pesticide claim

SENIOR officials from the Ministry of Agriculture, Fisheries and Food will spend today discussing the uncomfortable theory that the spread of BSE - 'mad cow disease' - may have been aided by a pesticide the ministry insisted on farmers using.

Mark Purdey, a Somerset-based organic dairy farmer, believes organophosphate pesticides (OP), used to treat Warble fly infestation, increase the susceptibility of cattle to BSE by altering their genetic make-up.

Dipping with OP solutions has already caused an outcry among farmers, some of whom who fear these are responsible for debilitating nervous disorders. The key to the Purdey theory is the observation that the symptoms of OP poisoning are similar to those of BSE.

Mr Purdey believes there is a correlation between areas of the UK where cattle were exposed to OPs, and incidence of BSE. He also saw temporary recovery in his own cows, showing BSE symptoms, when treated with solutions similar to those used to counter the effects of nerve-gas poisoning on soldiers.

The ministry has been reluctant to consider the evidence Mr Purdey has drawn up to support his heretical theory. Its scientists are convinced that the prime cause of BSE was feed, containing sheep and cattle protein, contaminated with an infectious agent similar to that which causes scrapie in sheep. They point to a declining number of BSE cases since the government ban on ruminant protein in animal feed as support for this view.

The biochemistry behind BSE infection has baffled scientists. The agent involved, possibly a form of protein produced in the brain, apparently transmits infection without having the expected virus-like characteristics.

Last September, Tom King, Mr Purdey's constituency MP and the former Secretary of State for Defence, wrote to the Minister of Agriculture, Gillian Shephard, urging MAFF scientists to consider Mr Purdey's theories. He also believes that he has been affected by OP sheep dip after helping out on his wife's farm.

Mr King sent the ministry a long paper by Mr Purdey in which he set out his hypothesis and evidence. This has been accepted for publication in the February issue of the Journal of Nutritional Medicine.

MAFF scientists have studied the document, which will form the focus of today's meeting at the Government's Central Veterinary Laboratory in Weybridge, Surrey. Among those attending will be the ministry's BSE co-ordinator, the head of its animal health division, the head of epidemiology at the laboratory, and representatives of the pesticides safety directorate and the veterinary medicines directorate.