Shepherd's pie, beef stew or Yorkshire pudding,
are being taken off the menu of the British
dinner table. Fear of the "mad cow disease"
known by the medical term "bovine spongiform
encephalopathy", or (BSE) is the reason.
The disease is thought to be caused by
rogue proteins called prions, which eat
away at cow's brains, eventually killing
them. This nation of beefeaters is worried
that the madcow disease may spread to humans.
This disease (BSE) first broke out in Britian
in the early 1980's. Today, infections are
appearing in 300 cows per week. Infected cattle
are supposed to be destroyed before they reach
the market. But since the incubation period
for the disease extends 8 to 10 years, some
infected cattle show up in slaughterhouses.
Public concern in recent months is that
contaminated meat is being sold, and eaten.
This worry over the contaminated meat started
with the deaths last year of two teenagers
from a malady known as "Creutzfeldt-Jakob Disease",
(CJD), the human equivalent of BSE, which is also
thought to be caused by prions.
Human CJD is an extremely rare, incurable
disease, only one person in a million gets
it. Similar to the bovine form, it has an
incubation period of up to 30 years, usually
appearing in people 45 years old and older.
It is hardly ever seen in those under 30 years
of age.
Moreover, within the last few years four
British farmers, all of whom had contact
with BSE-infected cows, died of CJD. This
might have been dismissed as coincidence
had not the incidence of CJD in Britian
increased with 55 new cases reported
recently.
Members of the British Parliment debating
this issue state as a consensus that there
is currently no scientific evidence that
BSE can be transmitted to humans, or that
eating infected beef causes the disease.
Medical authorities, on the other hand,
refute this statement, saying that they
would not eat beef "under any circumstances".
So far, there have been no reported cases
of the disease in American beef stock.
The causative agent of BSE cannot be
destroyed by heat or by radiation. It
can pass through filters that would ordinarily
catch a virus. No actual virus has ever been
found in infected cow's brains. What
has been found is a characteristic protein,
a "prion", believed to be the true
cause of the disease. Prions damage the brain
by converting its normal protein counterpart,
found in all body cells and known as PrP
(prion precursor), into new prions.
Can cow prions infect humans ? Investigators
in British medical schools are trying to find
the answer. They are studying genetically
engineered mice to carry only the human
gene for the PrP. It will take a few years
before they know the answer.
But, for now, do not worry about eating
American beef.
(Portions of this article were gleaned from
material in Medicine Watch, May 1996 Issue
of Discover Magazine.)
May 5, 1996 Michael W. Paparella The Shore Journal [moooooooo]Table of Contents |