WASHINGTON, DC, June 13,
2005 (ENS): A U.S. beef cow has tested positive for mad
cow disease, and a sample of the animal's brain has been sent to
an independent laboratory in the United Kingdom for confirmatory
testing, Agriculture Secretary Mike Johanns said late Friday night.
The suspect animal was a downer cow, one unable to walk, so it never
entered the food chain, Johanns said.
Only one case of mad cow disease has been confirmed in the United
States, in a dairy cow in Washington State in December 2003. Since
then, preliminary tests indicated the possibility of the disease
in three cows, but further testing had ruled out any infection.
USDA officials decided last week to perform additional tests, and
test results on one of those three cows turned up positive.
Johanns said the Agriculture Department Office of Inspector General
had recommended the additional testing, but the secretary did not
say why. The Inspector General's Office is an independent arm of
the department that performs audits and investigations.
Formally called bovine spongiform encephalopathy, or BSE, mad cow
disease happens when proteins in the body bend into misfolded shapes
called prions. Prions deposit plaque that kills brain cells, leaving
spongy holes in the brain. The disease is always fatal.
People can get a form of the disease, called variant Creutzfeldt-Jakob
disease, by eating contaminated meat. The disease has killed about
150 people worldwide, mostly in the United Kingdom, where there
was an outbreak in the 1980s and '90s.
Since the first case of mad cow disease was found in December 2003
in Washington state, about 375,000 U.S. animals have been tested
for the disease, usually those that appear sick.
Tissue from the three suspect animals has been tested three times,
using three different procedures.
Results were positive for one cow on one of the three tests. The
other tests were either inconclusive or negative for all three cows.
Initial screening called rapid tests indicated the potential for
mad cow disease in the three cows.
These three animals tested inconclusive in initial screening, called
rapid tests. Rapid tests check for mad cow disease by removing normal
proteins, then adding chemicals that bind to the abnormal BSE prions
so that researchers can see them.
Tissue from the three cows was was later subjected to immunohistochemistry,
or IHC, testing. The IHC is an internationally recognized confirmatory
test for BSE that stains brain tissue samples to highlight the misfolded
All three inconclusive samples tested negative using the IHC test,
said Dr. John Clifford, chief veterinary officer with the USDA's
Animal and Plant Health Inspection Service (APHIS).
Last week, the USDA Inspector General's Office recommended that
the three tissue samples be subjected to a second internationally
recognized confirmatory test, the Western Blot, or immunoblot. This
test destroys normal protein to leave only the abnormal prions.
Both tests both tests are accepted by the OIE, the World Animal
Clifford said USDA officials received the results of the Western
Blot test last Friday night, and, "of the three samples two
were negative, but the third came back reactive on that test."
"Because of the conflicting results on the IHC and Western
Blot test," said Clifford, "a sample from this animal
will be sent to the OIE recognized reference laboratory for BSE
in Weybridge, England. USDA will also be conducting further testing
which will take several days to complete."
Clifford hastened to reassure the public that no meat from the
suspect animal entered the food supply. "It was a nonambulatory
downer animal and as such was banned from the food supply,"
he said. "It was taken to a facility that handles only animals
unsuitable for human consumption, and the carcass was incinerated."
Both Johanns and Clifford said the U.S. meat supply is safe because
no "specified risk materials" are allowed into the human
food supply. These are nervous system tissues such as brain and
spinal cord tissues, the eyes, and the small intestine. These parts
are considered risky because in animals with BSE disease, the brain
and spinal cord contain the greatest concentration of the BSE agent.
The agriculture officials did not release the location where the
suspect animal was raised. They would only say that there was no
information that it was an imported animal. Clifford said the animal
was an aged animal. "It was getting up in age and was a beef
The age of BSE suspect animals is important because it takes at
least 20 months for the disease to develop.
Secretary Johanns emphasized that he did not want this discovery
of a suspect animal to derail beef trade talks now underway with
"I feel very strongly that this information should not impact
our discussions with Japan, Korea or Canada," he said.
"As the doctor pointed out, this is an aged animal,"
said Johanns. "Our discussions with Japan have related to 20
month animals as you know. Our discussions with Korea have related
to 30 month animals, and the rule relative to Canada, or the Minimal
Risk Rule in general, I should say relates to animals under 30 months
and meat product under 30 months."
The United States closed its border to Canadian beef after May
2003 when a BSE infected cow was found in Alberta.
Japan, which has had 20 cases of mad cow disease despite a policy
that requires testing of all cattle slaughtered for human consumption,
closed its borders to U.S. beef after December 2003 when the Washington
state mad cow was discovered. That cow was later found to have originated
The disease has thrown the beef industry in both the U.S. and Canada
An "industry in crisis" was the resounding theme of testimony
given at a USDA roundtable on BSE held Thursday at the University
of Minnesota in St. Paul. The roundtable discussion of U.S. beef
safety and the economics of BSE on the industry brought together
more than 200 attendees including USDA experts, producers, packers,
other industry groups and academics.
Secretary Johanns opened the discussion by explaining the critical
importance of the cattle and beef embargo to the U.S. beef industry
and its potential impact. Each day the border remains closed to
Canada there is an increased possibility that these changes will
become permanent, he said.
Johanns noted that one of the most recent victims of the embargo,
Packerland Packing, in Gering, Nebraska, announced last week that
they were closing their doors for good and laying off more than
Johanns said it is difficult to ban trade with Canada while trying
to open markets abroad. "It is difficult to ask Japan to treat
us one way when we are treating another major trading partner another
way,” he said.
APHIS Administrator Ron DeHaven, who was the agency's chief veterinary
officer when the first U.S. case of BSE was found, told the roundtable
that Canadian preventive measures are virtually identical to those
in the United States.
“The risk of BSE transmission in the U.S. and Canada is extremely
low,” DeHaven said, noting that "USDA is fully confident
that American and Canadian cattle are equally protected from BSE."
But others are not so sure.
News stories May 31 on Dow Jones Newswires and June 1 in the "Wall
Street Journal" revealed an internal USDA document called a
"decision memorandum" from October 2003, in which top
USDA officials reversed a May 2003 ban on imports of certain Canadian
processed and rendered beef products, including ground beef, that
could have potentially contained the BSE infective agent.
The memo stated that the expansion of imports requested by the
National Food Processors Association and others, “increases
the possibility that higher risk product ... may be imported into
the United States,” and warned that the decision would be
a “significant change in policy without opportunity for public
Bill Bullard, CEO of R-CALF United Stockgrowers of America, said
the memo shows that USDA has not adhered to sound scientific principles,
but rather has been basing critical decisions on inappropriate considerations,
including pressure from the meat processing and packing industries.
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