MINISTERS were fighting desperately this week to defend their decision
not to organise a partial slaughter of British cattle to eradicate BSE. They
argued, with the support of the Spongiform Encephalopathy Advisory Committee,
that a cull was not necessary.
The government says that existing measures, many in place since 1989, now
keep virtually all diseased meat out of the human food chain. It also argues
that cases of BSE in cattle are falling fast, and the disease will almost
certainly be gone within a few years. At its peak in 1992, an average of 700
cattle a week were going down with BSE. The toll so far this year is about 70 a
week (see
Graph, left).FIG-20230301.jpg
But from the corridors of Brussels to the queue outside McDonald鈥檚, the view
was that British beef was now guilty until proved innocent鈥攁nd SEAC
chairman John Pattison refused to discount all risk. Meanwhile, Richard
Southwood, the government鈥檚 chief adviser on BSE through the most critical early
years of the crisis from 1988 to 1990, said last weekend that he did not think
it was enough simply to allow the disease to disappear from herds of its own
accord.
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鈥淚f I was sitting on the SEAC committee I would push for a slaughter of all
animals born before the end of 1990 or early 1991, when farmers were still
feeding contaminated feed to their cattle,鈥� he said. That way, ministers 鈥渃ould
very quickly announce that monthly new cases of the disease were down to single
蹿颈驳耻谤别蝉鈥�.
But ministers rejected this idea. On Monday, SEAC said its 鈥渃ollective
judgment鈥� was that 鈥渁dditional measures鈥� such as wholesale slaughter were not
justified 鈥渁t this stage鈥�. It said that if its existing recommendations 鈥渁re
fully implemented and sustained鈥� any risk to humans 鈥渋s likely to be extremely
蝉尘补濒濒鈥�.
A key recommendation made by SEAC last week is that the carcasses of all
cattle aged over 30 months must have their bones removed in specially licensed
plants, and that trimmings such as vertebrae and nervous and lymphatic tissues
should be treated as banned offal. The recommendation follows growing concern
about slapdash abattoir practices that fail to keep potentially diseased
material separate.
Meanwhile, questions remained about whether BSE has actually caused the 10
deaths and two suspected new cases of an unusual form of CJD in young people,
which triggered the crisis (see page 6). Details of these findings are not
expected to be published in scientific journals for several weeks, and some
scientists are saying the cases may not be so unusual after all.
Gareth Roberts, a neuropathologist at the drugs company SmithKline Beecham in
Harlow, who has investigated prion diseases for a decade, says his research in
the country鈥檚 largest brain archive revealed unusual cases dating from before
the BSE epidemic hit cattle. Most, he says, were misdiagnosed as Alzheimer鈥檚
disease.
鈥淥ne case we found was a man who was aged only 40 when he died鈥攊n
1980,鈥� Roberts told New 杏吧原创. He published his findings, with
colleagues from the Corsellis Collection brain bank in Essex, last December in
the journal Neurodegeneration.
In a third of cases where CJD was misdiagnosed as Alzheimer鈥檚, he found the
distinctive slow-developing form that has recently set alarm bells ringing at
the government鈥檚 CJD Surveillance Unit in Edinburgh. In this form, the disease
follows a similar course to conventional dementia, with gradual loss of memory
and personality. 鈥淚 wonder if the people in Edinburgh have suddenly discovered
what we have already seen,鈥� he said.
According to Roberts, there could be many more such cases, possibly
undermining the hypothesis that BSE is to blame. 鈥淧sychiatrists often find weird
diseases that end in death. But often no neurophysiology is ever done.鈥� Fred
Pearce
* * *
For more information on BSE and prions see: 鈥淢ad brains and the prion
heresy鈥�, 28 May 1994, p 32; 鈥淏SE: what madness is this?鈥�, 9 June 1990, p 32;
鈥淢ad cows and ministers lose their heads鈥�, 11 August 1988, p27.