Abstract:
Introduction:
CSO 

It is already a multi-million pound disaster for 
British agriculture and now it threatens to erupt into a major 
political row between European governments. It is bovine 
spongiform encephalopathy (BSE) -- "mad cow" disease -- and few 
would be prepared to say exactly when and where it will end. 
  Next week European Community health ministers will meet to 
discuss a German call for a ban on British beef imports to that 
country. Some German politicians say their country should risk 
breaking Single Market free trade rules because the potential 
health risks are so grave. Nonsense, say British government 
scientists. 
  Meanwhile, the controversy in Britain is reaching new 
heights. Last week, the scientific journal Nature 
called for a start to be made on replacing the British cattle 
population with animals free from the infection -- which the 
magazine estimate would cost &pound;30 billion. 
  Next day, one of the farming industry's loudest voices, the 
magazine Farmers Weekly hit back at what it called "a 
diet of speculation, half-truths and downright lies" and 
denounced what it called "certain publicity-hungry scientists 
promoted by the media more interested in fiction than fact." 
Calling on the Ministry of Agriculture, Fisheries and Food 
(MAFF) to do more to explain the disease, the magazine 
concluded: "The alternative is to exacerbate the current climate 
of fear and uncertainty..." 
  The fear is not just that shared by farmers worried about 
their livelihood. Could it transfer itself from cows to humans? 
  "Mad Cow" disease was probably first observed on a farm in 
Kent in 1985, when four animals were put down after they were 
observed drooling, staggering before collapsing. Scientists at 
the Central Veterinary Laboratory in Surrey found that the 
animals' brains had become holed and spongelike -- similar 
symptoms to the disease scrapie in sheep and the rare 
Creutzfeldt-Jakob disease (CJD), in humans. 
  MAFF scientists concluded that BSE had appeared in cattle 
given processed feed that included remains of diseased sheep. 
New rendering methods, reducing the temperature at which the 
feed was prepared, were enabling the infective agent to survive, 
they concluded. Acting on this advice, in July 1988, John 
MacGregor, then Agriculture Minister, introduced a ban on such 
ruminant protein being used in feed. 
  Cattle confirmed as having BSE have been put down and 
incinerated, with the ashes being buried. In 1989 a further ban 
was introduced, on cattle offal sold for human consumption. That 
year it was officially predicted that 20,000 animals would be 
affected before the feed ban, together with the drying up of any 
supplies already on farms, had its effect. But the spread of BSE 
has confounded original expectations. The Ministry of 
Agriculture said yesterday that by the beginning of last week 
the total number of cattle diagnosed since November 1986 as 
having BSE had risen to 121,898 -- six times the original 
prediction. 
  The ministry believes that the reason more cattle have died 
is that farmers or food renderers kept using infected feed after 
the ban. Last week, MAFF said that the numbers of confirmed BSE 
cases in the first two months of this year showed a 20 per cent 
drop over the same period in 1993 -- proof, the ministry says, 
that the epidemic is waning. 
  Yet there is still controversy. Some 8,004 cattle have died 
from BSE despite being born after the feed ban was 
introduced. MAFF says 5,767 of these were born before the end of 
1988, and were probably fed from remaining infected supplies. 
  That theory has been assailed by critics of the ministry. 
Mark Purdey, a Somerset farmer and independent researcher, 
believes that the use of organophosphate pesticides, used from 
the 1980s as a sheep dip and to treat warble-fly infestation in 
cattle, could have damaged the animals' immune system, exposing 
them to the disease. Ministry scientists, originally dismissive, 
are now reassessing his theories. 
  More recently, researchers have suggested that in some 
cattle, BSE has been "vertically" transmitted from cow to calf. 
Given a long incubation period, such a possibility could make 
the disease harder to eradicate. This month 19 cattle have died 
on farms where MAFF is conducting a seven-year experiment into 
the disease. 
  It is a daunting possibility for the farming industry, which 
has responded angrily. "There is no evidence that this 
disturbing disease can be transferred from cow to calf," 
Farmers Weekly insisted last week. More cautiously, 
MAFF told The Sunday Telegraph: "We have never said 
we have ruled out the possibility of maternal transmission, but 
even if it occurs, our scientists do not believe it will do 
anything other than lengthen the time before the disease is 
eradicated." 
  So how long will it be before the epidemic is ended? Richard 
North, a former environmental health officer turned consultant, 
and a contributor to The Sunday Telegraph, believes 
that MAFF's statistics are being skewed to produce more 
optimistic figures -- claims not surprisingly rejected by the 
ministry. 
  Mr North said: "We have more than 8,000 cattle born after 
the 
feed ban that have subsequently contracted BSE. The claim that 
all of these are affected by illegally retained infected feed 
gets less credible by the hour." 
  One question -- perhaps the most important -- remains. If 
the 
disease has jumped from sheep to cattle -- and cases have also 
been reported in kudu antelope at London Zoo -- could it affect 
humans? 
  That prospect, discounted by most scientists -- including 
MAFF critics such as Mr Purdey -- is considered a possibility by 
Richard Lacey, a Leeds University microbiologist who has been 
studying cases of CJD, a disease with a long incubation period. 
  Reviled by the farming industry and privately disparaged by 
MAFF, he nevertheless insists that there may be a threat. "I'd 
expect an increase in cases of CJD by the early years of the 
next century," he says. "The bottom line is we just don't know 
what risks we may be running." 

