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From: TSS (216-119-129-63.ipset9.wt.net)
Subject: New mad cow case likely, experts say
Date: November 22, 2004 at 6:32 am PST

-------- Original Message --------
Subject: New mad cow case likely, experts say
Date: Mon, 22 Nov 2004 08:38:32 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@UNI-KARLSRUHE.DE


New mad cow case likely, experts say

Friday, November 19, 2004 Posted: 9:26 AM EST (1426 GMT)

WASHINGTON (Reuters) -- A final test is likely to confirm a second U.S.
case of mad cow disease, experts said on Thursday, though they see a
small possibility the animal, which tested "inconclusive" in two
preliminary tests, could be given a clean bill of health.

The U.S. Agriculture Department said earlier on Thursday the animal
tested "inconclusive" for mad cow disease in two rapid screening tests
and that it would conduct more sophisticated analysis for confirmation.
This was the first time two preliminary tests on the same animal
returned inconclusive since the USDA began its rapid testing program on
June 1.

The USDA said it would use a more sophisticated test, known as the
immunohistochemistry test, or IHC, to confirm whether there is a new
case of mad cow disease. Test results were expected in four to seven days.

"After two inconclusive results, you have a much higher rate of
confirming (mad cow disease) to the IHC test," Brad Crutchfield, vice
president of California-based Bio-Rad, told Reuters in an interview.

All the rapid screening tests used by USDA labs are from Bio-Rad
Laboratories. The company calls an inconclusive finding a reactive test
because it reacts to the BSE-specific prion protein.

"Greater than 95 percent of all doubly reactive tests are ultimately
confirmed (to have mad cow disease)," Crutchfield said.

For every 240,000 double positive tests, Bio-Rad said one was a false
positive after more sophisticated testing.

Barb Powers, director of Colorado State University's Veterinary
Diagnostic Laboratory, said it was rare not to have a mad cow case
confirmed after two inconclusive results.

However, a false positive in the final test was possible. Statistically,
Powers said a false positive could be expected after testing one in
100,000 animals for mad cow disease. The USDA has tested more than
113,000 since June.

USDA declined to comment on the likelihood this would be a mad cow case.
"They are inconclusive for the very reason that we just don't know,"
said USDA spokeswoman Alisa Harrison.

Live cattle futures at the Chicago Mercantile Exchange closed sharply
lower. The December live cattle contract (LCZ4) settled off 2.700 cents
per pound at 84.625.

Traders said this inconclusive test was so negative for the market
because it was the first time two preliminary tests were inconclusive
for the same animal.

"Thus far every time they have had an inconclusive, the second test has
negated it," said Bob Wilson, analyst with the livestock consulting firm
HedgersEdge.com. "This time the inconclusive sample was tested a second
time and it was still inconclusive."

In August, the USDA said it would repeat a screening test twice before
announcing an inconclusive result after finding two false positives last
summer. Before then, the USDA announced inconclusive results after a
single test.

Bio-Rad said human error was the likely cause of those two false
positives. The tests are extremely sensitive and can produce false
results if the brain samples are prepared improperly.

Animal health officials have used Bio-Rad's tests for more than six
months, sampling more than 113,000 animals.

"At these seven laboratories, USDA has highly trained and highly
competent people," Crutchfield said.

http://www.cnn.com/2004/HEALTH/11/19/madcow.biorad.reut/

Date: Wed, 24 Mar 2004 16:12:06 -0600
Reply-To: BSE-L
Sender: BSE-L
From: "Terry S. Singeltary Sr."
Subject: US CHOICE OF MAD COW TEST QUESTIONED

US CHOICE OF MAD COW TEST QUESTIONED


The US plans to measure the incidence
of mad cow disease in its cattle with a
test that its own officials have said gives
too many false positives. Some experts
fear the choice reflects an official desire
to downplay the impact of the first
positive BSE tests that emerge, when
they turn out not to be confirmed.


Last week the US Department of
Agriculture (USDA) approved two tests,
including one made by the Californian
firm BioRad, for screening up to 300,000
cattle for BSE, starting in July. No more
tests will be licensed for months.
Announcing the testing plan, chief
veterinary officer Ron DeHaven cautioned
that "there will be positive results",
many of them false.


BioRad's antibody-based test for the
prion protein that causes BSE has given
numerous false positives in Belgium and
Germany. And in Japan only 8 of 113 cattle
that repeatedly tested positive with
BioRad were confirmed by slower tests
that do not give false positives.


The USDA even wrote last May that
"it is well known" that tests like
BioRad's give false positives. It states
that other kinds of quick tests are more
suitable for testing for very low levels of
BSE, which are expected in the US.


The second quick test approved by
the USDA, made by Maine-based IDEXX,
could also in theory give false positives.
It remains unclear how reliable it is,
because there has been little practical
experience with the test so far. It is not
yet approved for use in Europe, where
the vast majority of BSE tests are done.

Debora MacKenzie,
Brussels correspondent,
New Scientist.
tel +32-2-245-0412
fax +32-2-245-0552
mobile +32-49-754-0444


http://www.newscientist.com/
=======================


Greetings,


odd that the USDA et al approves two US-OWNED tests that are
_known_ to give false positives, when they know other rapid
TSE test are much more reliable. IT's like they purposely do
not want to find any TSE in the USA bovine, so they pick the
worst test available. The USDA own experts think BioRad is
not suitable for supposedly BSE/TSE free and low incidence
areas, so why did they choose this test and or the IDEXX,
which i dont think has even been submitted to the EU for evaluation
and has no commercial experiance to my knowledge. You could
almost get the feeling they are deliberately skipping over
Prionics for the least supperior TSE rapid test. I believe
the Canadians finally did choose prionics. maybe paul or marcus
might comment? seems if North America is going to be a
consolidated BEEF trading market amongst themselves and expect
to export there tainted products everywhere, they could at least
come up with the same TSE rapid Test. how can one use a less
reliable test and the other use a more reliable test, and it
all be the same? i know there is a word Dehaven used, but it
slips my mind now, (consolidated markets) that's not it,
but you get the just of my thoughts, i think;-)...TSS


BSE-L


Date: Thu, 25 Mar 2004 00:53:39 +0100
Reply-To: Bovine Spongiform Encephalopathy
Sender: Bovine Spongiform Encephalopathy
From: Moser Markus
Subject: Re: US CHOICE OF MAD COW TEST QUESTIONED


BSE-L


Regarding your question about Canada's BSE-test choice for their
official BSE surveillance, I can confirm that they chose the
Prionics-Check Western rapid test.
Regards
Markus

######################################

Date: Thu, 25 Mar 2004 01:11:04 +0100
Reply-To: BSE-L
Sender: BSE-L
From: Roland Heynkes
Subject: Re: US CHOICE OF MAD COW TEST QUESTIONED
In-Reply-To:


BSE-L


Dear Terry,


> odd that the USDA et al approves two US-OWNED tests
> that are _known_ to give false positives, when they
> know other rapid TSE test are much more reliable.
>
the BioRad-test seems to be the most sensitive rapid
BSE test and it is clear that you "get" false positive
results when you try to confirm its results with a
less sensitive method like immune histochemistry.
Poorly trained technicians of course may produce
some false positives with the BioRad-test, but
immune histochemistry produces many false negatives
especially in the hands of not very experienced
people. Generally the false negative and not the
much fewer false positive results are the problem
of all actually available BSE tests.


It is therefore not so easy to say, if the BioRad-test
produced a false positive or if the confirming test
produced a false negative result and which of them
is more reliable. I for sure would not eat the meat
of a cow which was seemingly false positive tested
with the BioRad-test.


> IT's like they purposely do not want to find any
> TSE in the USA bovine, so they pick the worst test
> available.
>
The BioRad-test is definitively not the worst test
available (have a look on the EU results) and when
a government does not want to get positive results,
it uses immune histochemistry instead.


> The USDA own experts think BioRad is not suitable
> for supposedly BSE/TSE free and low incidence areas,
> so why did they choose this test and or the IDEXX,
> which i dont think has even been submitted to the
> EU for evaluation and has no commercial experiance
> to my knowledge.
>
Are you sure that USDA has experts for BSE testing?


> You could almost get the feeling they are deliberately
> skipping over Prionics for the least supperior TSE
> rapid test. I believe the Canadians finally did
> choose prionics. maybe paul or marcus might comment?
>
The Prionics western blot test is also a good rapid
test which of course does not produce false positive
results. In addition this test allows to see new
variants of BSE, which would not be seen with the
BioRad. But at least in Europe its positive results
become confirmed by the OIE Western blot exactly as
the BioRad results. Because of this control step
the BioRad test cannot produce significantly more
problems.


> seems if North America is going to be a consolidated
> BEEF trading market amongst themselves and expect
> to export there tainted products everywhere, they
> could at least come up with the same TSE rapid Test.
> how can one use a less reliable test and the other
> use a more reliable test, and it all be the same?
> i know there is a word Dehaven used, but it slips
> my mind now, (consolidated markets) that's not it,
> but you get the just of my thoughts, i think;-)...TSS
>
Not the minor differences between the rapid tests are
the problem, but the much to low testing numbers and
the prefered IHC-testing in the USA. In Germany we
test every month as many as the USA is going to test
per year (mostly with BioRad) - and we have only
13 million cattle.


kind regards


Roland


BSE-L


Date: Thu, 25 Mar 2004 02:51:09 +0100
Reply-To: Bovine Spongiform Encephalopathy
Sender: Bovine Spongiform Encephalopathy
From: Moser Markus
Subject: Re: US CHOICE OF MAD COW TEST QUESTIONED


BSE-L


Dear Roland
Immunohistochemistry, correctly executed, is the gold standard, together
with the OIE Western blotting method. It allows detection of infection
even in cases where prion aggregates can only be detected in few
individual cells. It is certainly not less sensitive than either Bio-Rad
or Prionics. In fact, the abundant data on all three methods indicate
equal diagnostic sensitivity (if sampling is done appropriate: note that
immunohistochemistry has to be conducted on different tissue samples,
since the tissue has to be formalin fixed). In case a BSE case obtained
with a rapid test cannot be confirmed in a first approach with one of
the gold standard methods, the second method will be used. I agree, that
the sensitivity of immunohistochemistry can be negatively influenced
e.g. by only looking at a limited number of slides or by not carefully
examining the slides for prion aggregates. However, if a rapid test is
not confirmed by immunohistochemistry due to a sloppy analysis, it will
still show up in the OIE Western blot. Nevertheless, it is of course
possible, that a true positive result cannot be confirmed e.g. if only
the tissue sample used for the initial testing contained prion
aggregates, which is theoretically possible, since the aggregates are
not evenly distributed in the tissue. This is why it is not formally
possible to disproof with 100% certainty an initial positive diagnosis
(and you are right: it's certainly wise to rather not eat any suspicious
animals). Nevertheless, false positives cannot in general be attributed
to faulty confirmatory tests, but to the fact that the ELISA method
simply produces a certain rate of false positives, which is why we offer
rapid BSE tests on both platforms, the ELISA and the Western technology.
And we make it clear to our customers, that when choosing the
Prionics-Check LIA (the ELISA based test) coping with occasional false
positive results will be inevitable. The LIA is therefore mostly used in
European countries, with well established levels of BSE, while the
Prionics-Check Western is also used in BSE-free countries (where a
maximum positive predictive value is important to support the conclusion
of low frequency or absence of BSE, which would otherwise be difficult
for the reason you indicated and I mentioned above, i.e. due to the
reason that it is hard to formally disprove an initial diagnosis with
absolute certainty).
Regards,
Markus

###################################

Date: Thu, 25 Mar 2004 12:30:21 +0100
Reply-To: Bovine Spongiform Encephalopathy
Sender: Bovine Spongiform Encephalopathy
From: Roland Heynkes
Subject: Re: US CHOICE OF MAD COW TEST QUESTIONED
In-Reply-To:


BSE-L


Dear Markus,


> Immunohistochemistry, correctly executed, is the gold
> standard, together with the OIE Western blotting method.
> It allows detection of infection even in cases where
> prion aggregates can only be detected in few individual
> cells. It is certainly not less sensitive than either
> Bio-Rad or Prionics.
>
this is correct in theory, but in practice there is the
human factor which hampers especially the IHC method. It
is a great method in a research lab with experienced
specialists and a lot of time, but it is not useful for
mass screening with the need to reduce all costs. And
in contrast to the rapid tests it highly depends on
people who are motivated to get positive results.


> In fact, the abundant data on all three methods
> indicate equal diagnostic sensitivity (if sampling
> is done appropriate: note that immunohistochemistry
> has to be conducted on different tissue samples,
> since the tissue has to be formalin fixed).
>
So it is and this means that it costs a lot of time
and effort.


> In case a BSE case obtained with a rapid test cannot
> be confirmed in a first approach with one of the gold
> standard methods, the second method will be used.
>
Will it? Not always. I know several cases in Germany
where weekly positive BioRad-tests were declared as
negative just because they were not confirmed by IHC.
And this happened although our case number 14 had shown
that after 2 positive results with BioRad the IHC was
negative and even the OIE Western blot was negative
after normal exposition period. Only when they prolonged
the autoradiography they were able to confirm this
only 29 months old case. After this experience I do
not trust in the reliability of US testing with this
method.


> I agree, that the sensitivity of immunohistochemistry
> can be negatively influenced e.g. by only looking
> at a limited number of slides or by not carefully
> examining the slides for prion aggregates.
>
Exactly this is the problem because this is what happens
in routine screening.


> However, if a rapid test is not confirmed by
> immunohistochemistry due to a sloppy analysis, it will
> still show up in the OIE Western blot.
>
Yes, when it is done. Is it done in the USA? Of course not,
because they use IHC for screening instead of confirming
rapid tests.


> Nevertheless, it is of course possible, that a true
> positive result cannot be confirmed e.g. if only the
> tissue sample used for the initial testing contained
> prion aggregates, which is theoretically possible, since
> the aggregates are not evenly distributed in the tissue.
> This is why it is not formally possible to disproof with
> 100% certainty an initial positive diagnosis (and you are
> right: it's certainly wise to rather not eat any suspicious
> animals). Nevertheless, false positives cannot in general
> be attributed to faulty confirmatory tests, but to the
> fact that the ELISA method simply produces a certain rate
> of false positives, which is why we offer rapid BSE tests
> on both platforms, the ELISA and the Western technology.
>
So it is.


> And we make it clear to our customers, that when choosing
> the Prionics-Check LIA (the ELISA based test) coping with
> occasional false positive results will be inevitable. The
> LIA is therefore mostly used in European countries, with
> well established levels of BSE, while the Prionics-Check
> Western is also used in BSE-free countries (where a maximum
> positive predictive value is important to support the
> conclusion of low frequency or absence of BSE, which would
> otherwise be difficult for the reason you indicated and I
> mentioned above, i.e. due to the reason that it is hard to
> formally disprove an initial diagnosis with absolute certainty).
>
An additional problem is, that there are TSE variants in which
the PrPsc is much less resistant against Proteinase K. Therefore
it would be a good idea to develop TSE tests without this
Proteinase-K-step. Do you have such a test in the pipeline?
What about your monoclonal antibody which seemed to react
specifically with PrPsc only? Can't you use this for such a
test?


kind regards,


Roland


BSE-L

TSS

http://www.vegsource.com/talk/madcow/messages/92794.html

* Re: U.S. CHOICE OF MAD COW TEST QUESTIONED
TSS
7/04/04 (3)
*

* http://www.vegsource.com/talk/madcow/messages/92798.html
o Re: U.S. CHOICE OF MAD COW TEST QUESTIONED

TSS 7/07/04 (2)
o

o http://www.vegsource.com/talk/madcow/messages/92801.html
+ Re: U.S. CHOICE OF MAD COW TEST QUESTIONED

TSS 7/09/04 (1)
+

+ http://www.vegsource.com/talk/madcow/messages/92808.html
# Re: U.S. CHOICE OF MAD COW TEST QUESTIONED

TSS 7/13/04 (0)
#

http://www.vegsource.com/talk/madcow/messages/92794.html

-------- Original Message --------
Subject: Positive BSE result likely, test-maker says
Date: Mon, 22 Nov 2004 08:23:59 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@UNI-KARLSRUHE.DE


##################### Bovine Spongiform Encephalopathy #####################

Positive BSE result likely, test-maker says

by Pete Hisey on 11/22/04 for
Meatingplace.com


Adding to speculation that USDA iss fairly certain it is dealing with a
valid case of BSE, Brad Crutchfield, vice-president of Bio-Rad, which
makes the rapid-screen tests used by USDA told CNN on Friday that a
positive finding is far more likely after two inconclusive results.

On Thursday USDA announced that a tissue sample had returned two
inconclusive test results for BSE. (See USDA: More rigorous test
methodology prompted BSE announcement
,
Meatingplace.com, Nov. 18, 2004.)

"Greater than 95 percent of all doubly reactive tests are ultimately
confirmed," Crutchfield said, adding that there remained a small chance
that this case will still be found to be a false positive.

Bio-Rad said that the two false positives reported last summer were
likely the result of human error, but said the double test regime and
the laboratories that have been conducting the tests since this summer,
which Crutchfield called "highly competent," make human error far less
likely in this instance.

================

BSE concern prompts National Beef to cut production

by Pete Hisey on 11/22/04 for
Meatingplace.com


Kansas City, Mo.-based National Beef Packing Co. announced that it will
reduce production hours in its processing plants immediately.

The company, the fourth largest beef packer in the country, blamed
anticipated impact on beef demand in the wake of the announcement of a
so-far inconclusive report of BSE made by USDA on Thursday.

National Beef has sales of $3.5 billion annually.

That development follows declines in stock prices and futures prices for
beef-related concerns on Thursday, after news of the inconclusive test
results reached markets. Those declines prompted the Livestock Marketing
Association to call on USDA to revise its announcement policy, which now
mandates public announcement if a sample tests positive twice in a rapid
scan test.

LMA President Randy Patterson said, "There is no consumer benefit, but
there is a major negative impact on the livestock industry, when
inconclusive BSE test results are announced." LMA urged its members to
protest directly to outgoing Secretary of Agriculture Ann Veneman's
offices.

http://www.meatingplace.com/DailyNews/init.asp?iID=13434

################# BSE-L-subscribe-request@uni-karlsruhe.de #################

TSS






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