A matter of brains: MAD COW DISEASE PANIC CONTINUES

From ANIMAL PEOPLE, May 1996:

LONDON, BRUSSELS, PARIS,
WASHINGTON D.C.––International panic
over the possible linkage of “mad cow disease”
with the brain-destroying Creutzfeldt-Jakob
disease in humans, just beginning to wane as
the May edition of ANIMAL PEOPLE went
to press, may rebound with the publication of
data suggesting that the disease may be carried
from species to species by mites––and may be
virtually impossible to eradicate.
“You could remove all the poor cows
and then find that weren’t even the source in
the first place,” said Henryk Wisniewski,
whose team at the New York State Institute for
Basic Research in Developmental Disabilities
discovered the possible role of mites, publishing
their findings in the The Lancet, a leading
British medical journal. Exploring the theory
that bovine spongiform encephalopathy is a
mutated form of the sheep disease scrapie,
Wisniewski injected hay mites from a scrapieplagued
part of Iceland into the brains and
abdomens of 71 mice. Ten of the mice developed
the microscopic spongelike holes in the
brain that are symptomatic of scrapie, BSE,
and CJD.

“There is no question that the mite
agent crossed the species barrier,” Wisniewski
said, suggesting that the findings may explain
why healthy sheep often develop scrapie just
from being in the same barns and fields that
infected sheep occupied as long as five years
before.
The same tendency has been seen in
some British cattle herds, but the number of
infected cattle peaked at 10,403 among cows
born in 1989, falling to 3,140, 956, 48, and
one among cows born in each ensuing year
through 1993.
The leading current theory about the
mode of transmission is that scrapie somehow
jumped into cattle via processed offal supplements
that until 1989 were commonly used in
Britain to fortify feed grain. Even after the use
of potentially infected offal in cattle feed was
banned in Britain, British processers exported
15,674 tons of feed containing cattle offal to
France, and 13,480 tons to The Netherlands.
Offal cattle feed supplements are still
commonly used in the U.S. and Canada.
Cannibals
How exactly BSE might have gone
from cattle to humans, if it did, is still
unclear. While consumption of bovine nerve
tissue would be an obvious possibility, two of
the known victims of the unique form of CJD
believed to be related to BSE have been vegetarians––who
may, however, have consumed
protein supplements made from infected cattle,
unaware of their animal content, or might
have eaten meat from diseased cattle at some
point prior to becoming vegetarian. The infectious
agent for scrapie, BSE, and CJD is
apparently a rogue form of a kind of protein
particle called a prion. Prions are normally
found on the surface of nerve cells. The disease-causing
proteins, though they carry no
genetic material, apparently can somehow
convert normal prions into the abnormal and
deadly kind.
Wisniewski’s findings suggest
chiefly that the disease-causing prions may
have multiple avenues of transmission.
Until the appearance of 10 CJD cases
in Britain among people younger than age 42,
CJD was found only in elderly people and
seemed to have a hereditary component, since
cases clustered in one region of Slovakia,
among Libyan immigrants to Israel, and
Sephardic Jews who immigrated to France
from Tunesia and Algeria. At least 62 cases
were linked to injections of human growth hormone
taken from cadavers; others were linked
to corneal transplants. A similar disease,
kuru, was formerly found among the Fore cannibals
of Papua New Guinea, but has disappeared
with the decline of cannibalism.
Comparable diseases have turned up in cats,
ranched mink, squirrels, and deer.
Investigation of possible avenues of
BSE/CJD transmission turned up news that
shocked Switzerland on April 5, when officials
of two Zurich hospitals admitted that for
20 years they had sold human placentas to cattle
feed producers. Zurich chief veterinarian
Regula Vogel immediately stopped the practice,
but said it had never been illegal.
Switzerland has had the most BSE cases of any
nation other than Britain.
Texas to sue?
The BSE/CJD scare gave advocates
of vegetarianism unprecedented opportunity to
talk about beef and health before mainstream
audiences. Former Montana rancher Howard
Lyman was apparently particularly effective on
the April 16 Oprah Winfrey Show. After
Lyman’s appearance, live cattle futures
crashed on the Chicago Mercantile Exchange,
prompting Texas agriculture commissioner
Rick Perry to demand that state attorney general
Dan Morales prosecute Lyman for using
“sheer innuendo and deceptive insinuation” to
defame a food product in violation of a state
law against circulating false information that
“implies that a perishable food product is not
safe for consumption by the public.” Lyman is
currently executive director of the Eating With
Conscience Campaign, a project of the
Humane Society of the U.S.
In Britain, anti-pesticide campaigner
Mark Purdey argued that BSE was produced
by livestock being exposed to organophosphate
pesticides, particularly phosnet, a blend of
organophosphates with the notorious drug
thalidomide, which British farmers were
obliged to use in the 1980s to fight a warble fly
outbreak. Purdey’s theory was carefully considered
by participants in the PRO-MEDAHEAD
online discussion of zoonotic disease,
sponsored by the World Health Organization,
but was generally rejected because the effects
of organophosphates have a well-established
path of attack, which CJD cases do not follow.
The British government labored
unsuccessfully from mid-March to mid-April
to lift boycotts of British beef imposed by virtually
every regular overseas buyer. At the
beginning of April, officials seemed resigned
to eventually having to slaughter the entire
British cattle herd of 12 million, burning the
carcasses to prevent anyone from rendering
them into any product for either human or animal
consumption. The European Union on
April 2 agreed in principle to pay 70% of the
cost of the BSE eradication effort. On April
17, however, the EU balked at the scale of the
projected killing, which had been diminished
to a target of 4.5 million cattle, all of those
now more than 30 months old, who are
believed to be at most risk of carrying BSE.
These would be killed at the rate of 15,000 a
week, or 700,000 a year, for the next five to
six years, at cost of $1.5 billion a year.
Britain was to present a plan on
April 29 for burning the remains of the culled
cows at power plants.