DC, June 28, 2004 (ENS): Another cow infected
with bovine spongiform encephalopathy (BSE), or mad
cow disease, has been inconclusively identified by U.S.
Department of Agriculture (USDA) authorities, but the
official announcement late Friday was more notable for
what it did not reveal to the public than for what it
Dr. John Clifford, deputy administrator of the USDA
Animal Plant Health Inspection Service's Veterinary
Services Program, would only say that the agency received
notice that an "inconclusive BSE test result was
received on a screening test" used as part of the
government's surveillance program.
"Tissue samples are now being sent to USDA's National
Veterinary Services Laboratories, the National BSE Reference
Lab which will render additional testing on this sample,"
said Clifford, who expects results sometime after Tuesday
"The animal in question did not enter the food
chain, and the carcass is being held," Clifford
While saying that the agency wanted to be "transparent"
Clifford would say no more. He would not disclose what
type of animal was tested, where the animal was from,
or which lab did the testing.
Clifford would say only that a positive test "is
not at all unexpected."
"The inconclusive result does not in and of itself
mean that we have found another case of BSE in this
country," he said. "Inconclusive results are
a normal component of most screening tests which are
designed to be extremely sensitive so they will detect
any sample that could possibly be positive."
"Second, no matter how the additional testing
comes back, USDA remains confident in the safety of
the U.S. beef supply," said Clifford.
Transmissible spongiform encephalopathies, such as
mad cow disease and its human form, variant Creutzfeldt-Jakob
Disease (vCJD), are spread by prions - abnormally shaped
proteins that originate as regular components of neurological
tissues in animals. They are not cellular organisms
or viruses, according to the U.S. Food and Drug Administration.
Mad cow disease spreads from one animal to another
by consumption of feed that has been contaminated by
these prions, such as blood or meat meal that contains
nervous system tissue from an infected animal. The human
form of the disease can be transmitted if a human being
eats BSE infected meat, or possibly through blood transfusions.
The ban on nervous system tissue in the human food
chain, "provides the utmost protection to public
health should another case of BSE ever be detected"
in the United States, Clifford said.
Safety measures include a ban on the use of most mammalian
protein in cattle feed that has been in place since
After a BSE infected cow was discovered in Washington
state last December, the USDA banned downer cattle from
the human food chain and tightened the process control
for establishments using advanced meat recovery systems.
The agency prohibited the air injection stunning of
cattle that can force nervous system tissue into muscle
The practice of holding the carcasses until BSE test
results have been confirmed negative was also put in
place early this year.
U.S. trading partners around the world have banned
imports of U.S. beef, costing the beef industry dearly.
The total value of global beef exports in 2003 is about
In 2003, 10 percent of U.S. beef production was exported
- 3.6 percent to Japan, 2.4 percent to Mexico, 2.3 percent
to South Korea, 0.9 percent to Canada and the remaining
0.8 percent to other countries.
All major export destinations except Canada suspended
imports of U.S. beef. Although Mexico has now reopened
its border to U.S. beef, most other countries that banned
it have not. Japan requires BSE testing of 100 percent
of all animals that provide beef for export to Japan
before it will reopen its border to U.S. beef.