CATHY'S CORNER
Mad
Cow Disease - The Untold Story
On March 20th, a thousand US
communities of all 50 states were observing the Great American Meatout.
Across the Atlantic, British Health Secretary Stephen Dorrell was
conceding to a startled house of Commons that recent cases of
Creutzfeldt-Jakob disease (CJD) were probably linked to consumption of
beef infected with bovine spongiform encephalopathy (BSE), the dreaded
'Mad Cow Disease.'
The
media rushed to judgment with banner headlines warning of the new threat
of British beef. Yet, even a brief review of the evidence shows that the
threat is not peculiarly British, bovine, new, or unmanageable.
What
is BSE?
Spongiform
encephalopathy is actually a family of diseases that afflict humans, (CJD
and Kuru), sheep and goats (scrapie), cattle (BSE) and other mammals.
These diseases share important traits.
The
agent is a deformed brain protein molecule called a "prion,"
capable of deforming other protein molecules. As it involves no DNA or
RNA, the prion is highly resistant to heat, radiation, and most common
chemical disinfectants. Transmission occurs through ingestion of
infected tissues (brain, spinal cord, spleen), transfusion, or
gestation.
The
pathology is an irreversible degeneration of brain tissue, forming a
sponge-like structure. Symptoms include erratic cognition, emotions,
behavior, and movement, followed by death within one year. These don't
appear until 2-3 years after infection, in animals, and 10-20 years, in
humans. Since prions do not trigger an immune response, there is no
known test or cure.
The
problem is not peculiar to British beef, because most industrialized
countries, including the US, routinely feed infected slaughterhouse
offal [trimmings, waste or by-products of butchered animals] to cattle
and to all other animals raised for food. This is the most common
transmission route for spongiform encephalopathy. The unusually high
incidence of BSE in Britain (157,000 cases since 1986) may well be due
to British dairy cows being the only farm animals allowed to live long
enough to exhibit symptoms.
History
of the Disease
Spongiform
encephalopathy is certainly not new. BSE was first noted in 1883. Its
human counterpart was described by Creutzfeldt and Jakob in Germany in
the 1920's. Scrapie was observed in goats and sheep in 1942. Kuru was
discovered in 1957 among New Guinea tribesmen who consumed human brains.
The prior was characterized as the agent in 1980 by Stanley Prusiner at
the University of California.
Handling
of the disease by British and other public health officials may be
characterized by a series of milestones:
1986
- BSE first observed in Great Britain.
1987
- BSE linked to ruminant protein feed.
1988
- Britain bans ruminant protein feed.
1989
- European Union bans cattle export.
1994
- EU bans mammalian protein feed.
1996
- Britain concedes BSE-CJD link.
Nature
of the Threat
The
threat of CJD to American consumers is framed by two questions:
"Can it happen here?" And "How does the risk compare with
that of other diseases linked with meat eating?"
Yes,
it definitely can and will happen here. Although import of British
cattle was banned in 1989, feeding of infected offal to farmed animals
has continued. Approximately 13 percent of ruminant-derived protein
[ground up animal by-products] is fed to cattle, 34 percent to pigs, and
17 percent to poultry (the rest ends up in commercial pet food).
In
1985, a year before BSE was first observed in Britain, Richard Marsh at
the University of Wisconsin traced an outbreak of spongiform
encephalopathy in farmed mink to protein powder from rendered cows in
their feed. The cows had died suddenly from the "Downer Cow
Syndrome" which afflicts 20,000 animals annually in Wisconsin
alone.
The
Food and Drug Administration is considering a ban on feeding ruminant
protein just to cattle. However, only a total ban on the barbaric
practice of feeding animal flesh to the mostly vegetarian animals raised
for food can wipe out the CJD threat.
On
the other hand, for every consumer likely to die of CJD, tens of
thousands are certain to suffer and die from heart disease, stroke,
cancer, and other chronic diseases linked conclusively with consumption
of animal fat and meat.
What's
At Stake For the Animals?
In
the short run, we may rejoice in the collective anxiety of the US beef
industry and the free fall of cattle futures on the Chicago Mercantile
Exchange. We may relish the likely ruin of the $6.5 billion British beef
industry. We may certainly savor the sign posted at a London McDonald's
offering vegetarian burgers in place of hamburgers. But, the long-range
fallout for farmed animals from the BSE scare is rather dismal.
Britain
has already agreed to incinerate or otherwise destroy the carcasses of
4.7 million dairy cows over 30 months old, at the end of their
productive life of 6-7 years. (No animal born after early 1993 has
exhibited symptoms of BSE.) Some of the resultant meat supply shortfall
will be filled by abusing and killing more cattle. Most, however, will
be filled by abusing and killing 250 chickens for each forgone cow.
What's
At Stake For Us?
We
must alert the public that the threat of CJD from eating chickens is no
less than that from eating cows. Chickens are fed more infected animal
protein than cows; they are likely carriers of the disease; they just
don't live long enough to exhibit the symptoms. We must convince
consumers that chicken is not a 'health food,' but a reliable source of
saturated fat, cholesterol, Salmonella, and perhaps 'Crazed Chicken
Disease.'
Reprinted
by permission.
FARM
REPORT
Spring/Summer
1996
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