Warning: some statistics can drive you mad

After an absence of nearly a year, the mad cow is back in the headlines. Timed to coincide with Halloween and the onset of winter, the now-familiar bogey is among us again, raising the hairs on the backs of our necks and complicating the shopping. "Experts fear 1.5 million 'mad cows' eaten," brays the Sunday Times. "New fear of mad cow link" declared Monday's Daily Mail.

The good news is that these sensational stories are erected on statistical matchwood. BSE, popularly known as "mad cow disease", continues to afflict herds of British cows - 9,602 diseased cows have so far been slaughtered this year - despite the drastic efforts of the Ministry of Agriculture, Food and Fisheries to uproot it. But that is a problem for the farmer and the taxpayer who compensates him, and a declining one at that: BSE numbers have been falling since 1992, when 36,681 British cows were affected. It is not directly a problem for the consumer.

The consumer's anxiety is focused not on these figures but on the human equivalent of BSE, the terrible degenerative brain ailment which culminates in death, Creutzfeldt-Jakob Disease (CJD). If these figures were to show a steep rise, there would be good reason for public alarm. But last year in Britain only 54 people died from the disease, a figure comparable to Germany (58) and France (47) where BSE is practically unkown. Deaths in Britain have increased substantially in the past few years, but it is plausibly argued that this is because the National CJD Surveillance Unit in Edinburgh, galvanized by public concern, has intensified its efforts and thereby detected more cases.

The real reason for the mad cow's return to the headlines is that scourge of the age, the misdirected fax. Doctors and scientists on the government's Spongiform Encephalopathy Advisory Committee mis-faxed a secret report, which was obtained by the Daily Mail, on recent cases of CJD, noting that a fourth farmer had apparently contracted the disease and "the Committee concluded that it was difficult to explain this as simply a chance phenomenon. There is a statistical excess of cases in cattle farmers compared to the general population..." Yet even this could reasonably be dismissed as scholarly excess of scruple: the incidence of CJD among farmers, after all, is no more than two per million. And statistically, the group most at risk from the disease is not farmers but vicars, with 11.8 cases per million. This says more about statistics than it says about the Church of England.

But it is more than a shortage of other things to write about that draws journalists back over and over again to the case of the mad cow. The success of the government last year in reversing the German ban on imports of British beef, and the persistently low incidence of CJD, should not deflect attention from the fact that certain urgent questions remain unanswered.

Most importantly, if, as has been proved, BSE can spread to cats, ostriches, antelopes, pumahs and cheetahs - in all cases, it appears, through the use of infected feed in zoos - how can anybody declare with certainty that it will not cross, or has not already crossed, the species line to humans, too?

Headlines such as the Sunday Times's may invite mockery, but the incubation period for kuru, a similar brain disease to CJD found among a particular cannibalistic tribe in Papua New Guinea, has an incubation period of about 30 years. We cannot with absolute certainty rule out the possibility of a very nasty epidemic of CJD in Britain sometime around 2015.

Secondly, why has the disease continued to ravage British herds five, six and seven years after the ban on infected feeds and the wholesale slaughter of infected animals?

Thirdly, why should prudent people continue to give credence to the reassurances of MAFF - a ministry which has presided over a succession of agribusiness disasters, all brought about by its own policies? When a government department is, like MAFF, under intense pressure to shore up an important national industry, would not the consumer be safer off just saying no to beef?

Of all Thatcher's children, bovine spongiform encephalopathy may well be the most gruesome. As part of the fever for deregulation that gripped Whitehall in the early Eighties, producers of cattlecake - which routinely included minced up bits of sheep and cattle carcasses as well as grain - were enabled to cut out a couple of key steps in manufacturing process. As a result, tissue of brains of sheep which were infected with the long- established sheep disease scrapie managed to survive into the finished feed, and thereby made their way into the stomachs of cows.

Farmers watched helplessly as the appalling illness gripped their herds. The animals' eyes glazed over, their ears swivelled, they constantly licked their lips; dairy cows had to be dragged in to be milked, and when the clusters were fitted they were liable to kick out violently. Later they would stagger and sprawl on the ground.

The disease was first identified in 1986 and decimated herds all over the country before, in the summer of 1988, the Secretary of State for Agriculture, John MacGregor, decided on drastic action and instructed all affected animals to be slaughtered. But like Herod's comparable project in Bethlehem (or the government's earlier genocide on chickens in the wake of the salmonella scare), it didn't work. The disease continued unabated.

The effect on the British beef and dairy industry was devastating. Practically every herd in the country lost some animals, and the compensation offered by the government did not even make good the financial loss, as only half the value of the cows was paid out. After all, said a spokesman for MAFF, who had clearly read Catch-22, the animals were sick. But more fearful than mere financial loss was the threat of the extinction of the entire industry, with its livestock holdings worth more than pounds 2bn, its pounds 500m exports, its 137,000 head of cattle. Germany's decision last year to halt imports of British beef meant little in itself: Germany only imported pounds 3m worth of British beef per year anyway. But if the German view had prevailed in Europe, the rest of the European market, including the pounds 77m exports to France, could have vanished, too. It might have been the beginning of the end. But Helmut Kohl blinked first. The Germans changed their minds.

The one success story in this whole sad saga was MAFF's achievement last year in transforming the debate on the issue from Mad Cow versus the British public to plucky British farmers versus bullying bureaucratic Germans. Amidst the ensuing paroxysms of chauvinism the central issue - the health and longevity of meat eaters, wherever they might be - almost disappeared from view.

The spate of sensationalising stories of the past few days has done the useful service of reminding us that behind the smokescreen of national pride and Teutonic infamy, the mad cow problem had stubbornly refused to go away. Most alarming of all was the fact that, as the continuing deaths served to rub in, the cause of the epidemic had not necessarily been isolated. The ministry insisted that infected feed must be at the root of the problem. But when an organic farmer from Somerset called Mark Purdey asserted that BSE was caused by something quite different - by the use of organo-phosphorous treatments for other animal ailments - the ministry's leading scientists paid him the compliment of listening to his case. They reject his thesis. But nobody has yet succeeded in isolating the positive agent of the virus. A great deal of mystery and ignorance continues to surround it.

Meanwhile Britain's beef industry is like the population of southern California as they contemplate their next, inevitable earthquake: sitting tight, waiting for the Big One which will wipe the industry off the map. The scare in 1989, when beef sales plummeted pounds 10m in a weekend, was only a taster for the real thing. It is a perilous and unenviable situation to be in, knowing that the next batch of CJD statistics - even a purely chance run of CJD cases among vets or dairymen - could deal the industry a fatal blow.

Yet pity and concern are not adequate emotions here. The evils besetting British farming have been brought on by greed and lack of wisdom: as the man from the Meat and Livestock Commission put it, "This is a forward- looking industry, always looking for ways of cutting costs, increasing output and making itself more efficient." Whether infected sheep feed or organo-phosphorous treatments are to blame, it is beyond doubt that the cause of the problem, seen in the larger context, is the industrialisation of farming.

Without much fanfare, a number of key People Who Know in the medical profession have given up eating beef: the latest was Sir Bernard Tomlinson, architect of the NHS reforms, who recently admitted he was less sure than previously that BSE could not jump the species barrier. Those who value their lives would do well to study their example.

BSE: the first ten years

November 1986:

Bovine spongiform encephalopathy is first identified, after a spate of cases during 1985. Cattle are thought to have caught it from eating the offal of sheep infected by scrapie.

April 1988:

The Government appoints a committee, under Sir Richard Southwood, to assess the significance of the BSE epidemic.

June 1988:

The Southwood Committee reports back with immediate recommendations: that infected animals be destroyed, that milk from infected animals be disposed of, that BSE be made a notifiable disease and that a research committee be set up to discover the full extent of the threat to animals and the potential threat to humans.

July 1988:

The Government bans feed made from ground cattle and sheep remains.

August 1988:

The Government orders the slaughter of all BSE-infected livestock.

February 1989:

The Southwood Report is finally published, claiming that "it is most unlikely that BSE will have any implications for human health".

May 1990:

A Creutzfeldt Jakob disease surveillance unit is established in Edinburgh, headed by Professor Robert Will. In defence of British beef, the Minister of Agriculture, John Gummer, persuades his four-year-old daughter to eat a beefburger before the assembled British press.

March 1993:

Dairy farmer Peter Warhurst dies from CJD two years after the slaughter of an infected animal on his farm.

July 1993:

Mark Duncan Templeman, also a dairy farmer and also having lost livestock to BSE, dies from CJD.

May 1995:

Stephen Churchill, aged 19, becomes Britain's youngest victim of CJD. Another teenager, Vicky Rimmer, is suspected of having the disease (she remains in a deep coma).

September 1995:

A third, so far unnamed, farmer is revealed to have died from CJD.

October 1995:

A government report reveals that twice as many people died from CJD in Britain last year as in 1985, the year of the first recorded cases.

SCOTT HUGHES