The precautionary principle -
the lessons of BSE
BSE (Bovine Spongiform Encephalopathy,
or Mad Cow Disease) became widespread among cattle in the UK
in the mid-1980s. It had probably been spread to cattle through
the use in feed of minced sheep infected with Scrapie, a similar
brain disease which has been around for centuries. Both these
diseases are probably spread by a prion, a deformed protein,
and they both lead to a gradual destruction of the brain of victims.
Once the existence of the BSE outbreak
was revealed, there was concern that it might spread to humans.
There was already a similar disease known in man, CJD (Creutzfeldt-Jakob
Disease), a fatal neurodegenerative disorder. For 10 years the
UK government position was:
"There is currently no scientific
evidence that BSE can be transmitted to humans or that eating
beef causes CJD in humans. That issue is not in question"
(John Major, The Prime Minister, Dec.1995)
Some (poorly policed) restrictions were
placed on human consumption of beef offal (e.g. brains) to reduce
transmission to humans, but the emphasis was that there was not
Until Wednesday 20 th of March 1996, when,
after 10 cases of a new form of CJD in young people, the then
Secretary of State for Health, Stephen Dorrell said that:
"The most likely explanation is
that these cases [of CJD] are linked to exposure to BSE before
the offal ban in 1989"
This statement has led to the virtual collapse
of the British beef industry, a total export ban and a cost of
at least 3.5 billion pounds. No-one knows whether the number
of CJD cases will be in the tens, hundreds or thousands - as
at 7th October 1999 there were 44 confirmed cases and two probable
cases of the new variant of CJD in the UK, and one case in France;
for the latest figures see the web site of the UK
Creutzfeldt-Jakob Disease Surveillance Unit.
Even after the Government acceptance of
the probable link, the Beef Industry initially continued to produce
posters stating 'There is no proof of a link between BSE and
CJD', whilst not mentioning that the link was 'likely'. Statements
of this sort are very dangerous for industry, since if (or when)
new evidence appears, they have to back down, and the industry
looses public confidence. New evidence then appeared (Nature,
Vol. 383, p666-667, and p685-689, 24th October 1996) providing
very strong evidence that the new CJD variant is the same prion
strain as BSE, and different from the other CJD variants. The
UK Government accepted that this result virtually proves the
Why did the UK Government get itself into
- They refused to apply the precautionary
principle - it was shown that BSE could transfer to a wide range
of other animals, but they assumed it would not transmit to humans
- They kept using phrases such as 'no evidence
of human transmission', whilst not acknowledging that there was
no evidence either way ('absence of evidence is not evidence
- They did not carry out much important
research, possibly because they did not want to learn the answers:
e.g. examining the brains of cattle in slaughter houses, to establish
the true rate of BSE infection, rather than just those cows that
went visibly 'mad', or testing whether primates could get BSE.
The BSE enquiry
The Labour Government which came to power
in the UK in May 1997 has initiated a major public enquiry into
the BSE crisis. It has its own comprehensive
and regularly updated web site.
An excellent source of the latest news
and information on BSE/CJD is the site run by Steve
Dealler (a Medical Microbiologist).
Relevance to the potential risks of hormone
There is considerable evidence from cell
culture and animal studies that the chemicals described in these
pages disrupt hormone signalling pathways. Therefore, as I have
outlined elsewhere in these pages (and on the Friends
of the Earth site), I believe these chemicals should be phased
out because they could potentially be damaging humanity, and,
in many case, have been shown to damage wildlife.
The response of Government and Industry
to these opinions is that 'we require proof of human harm'. The
BSE crisis, with its massive cost in terms of cash, and increasing
cost in lives, demonstrates the folly of waiting for visible
harm to humans.
Whenever someone makes a statement 'there
is no evidence that.....', ensure that they are not actually
saying 'there is no evidence either way'.