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Secretary of Agriculture Mike Johanns announced during a
Friday night phone conference that the animal that yielded
a presumptive positive for bovine spongiform encephalopathy
last November using rapid testing, and then negative for
the disease after immunohistochemistry (IHC) testing was
performed, has since returned a positive result under the
Western blot test.
Brain samples have now been sent to OIE's BSE World Reference
Laboratory in Weybridge, England, for an impartial third-party
review. Results are expected later this week.
After USDA's Inspector General made the recommendation that
three cattle, including the animal testing positive in November,
be retested for BSE using the Western blot, samples were
sent to a USDA laboratory in Ames, Iowa, where the other
two animals were confirmed as negative. Experts argue about
which BSE tests are most reliable, but Dr. Jean-Philippe
Deslys, a world-renowned expert in BSE and other prion diseases,
told Meatingplace this spring that if
results are in question, Western blot generally is considered
conclusive.
"We…have no information that it was an imported animal,"
said APHIS Chief Veterinary Officer Dr. John Clifford, who
described the animal as "aged."
"It was getting up there in age and was a beef breed," he
said. "That's what we're willing to release at this time."
Clifford also noted that when the Western blot was used
on the U.S. animal that tested positive for the disease
in December 2003, only one milligram of brain material was
used and it returned a "very strong positive." In this case,
far more material was used, and then concentrated, to detect
the disease, and as such, Clifford typified Friday's result
as a "weak positive."
Clifford emphasized "we have not confirmed a case of BSE
in the U.S. at this time. We're going to do further analysis
and study on this."
Johanns stressed that trading partners have assumed that
BSE exists in the U.S. at some level, and if the animal
is confirmed to have suffered from BSE, the discovery will
not affect negotiations with those partners, most notably
Japan and South Korea. "The firewalls that the USDA put
in place worked," Johanns said. "The animal did not enter
the food or the feed chain. Therefore, there is no risk
to human health."
Jim McAdams, president of the National Cattlemen's Beef
Association, said in a statement that "U.S. beef consumers
should know that our beef supply is safe from BSE because
we prohibit from the food supply any material that could
carry the BSE agent. USDA also bans from the food supply
any cattle that appear to be high-risk, including this animal.
This aged animal never entered the human food or animal
feed supply."
"NCBA supports getting a clear and definitive answer on
this sample as quickly as possible and requests USDA Secretary
Johanns take whatever steps necessary to do so," McAdams
continued.
James Hodges, president of the American Meat Institute Foundation,
emphasized that the news "reflects USDA's commitment to
a transparent, robust testing program and consumers should
not be concerned about the safety of beef." |
