![](media/image1.jpeg){width="3.28125in"
height="0.8333333333333334in"}Center for Food and Nutrition Policy

1101 King Street

Suite 611

> Alexandria, VA 22314

Phone: 703-518-2705

> Fax: 703-535-8234
>
> Email: mstorey@vt.edu

August 13, 2004

Docket No. 2004N-0264

Food and Drug Administration

Division of Dockets Management

5630 Fishers Lane

Room 1061

Rockville, MD 20852

Email: <fdadockets@oc.fda.gov>

RE: Docket No. 2004N-0264

> RIN 0910-AF46
>
> Federal Measures to Mitigate BSE Risks: Considerations for Further
> Action.

The Center for Food and Nutrition Policy ("Center" or CFNP) of Virginia
Tech---National Capital Region is an independent, non-profit research
and education organization that is dedicated to advancing rational,
science-based food and nutrition policy. It is recognized as a Center of
Excellence on such matters by the Food and Agriculture Organization of
the United Nations (FAO). The Center uniquely operates like an
independent "think-tank," while maintaining its academic affiliation
with a major land-grant university. The research, education, outreach,
and communications activities of the faculty are conducted in a
relevant, time-sensitive manner that helps inform the public policy
process on food and nutrition issues.

Encompassed in the Center's activities on food policy are its interests
in regulatory issues involving food safety, food security, and food
defense. As such, the Center respectfully submits the following comments
in response to the Food and Drug Administration (FDA) request for
comment on Federal Measures to Mitigate BSE Risks: Considerations for
Further Action, docket number 2004-0264 as published in the *Federal
Register*.[^1]

**[Overview of the Comments]{.underline}**

The Center recognizes the important role that FDA has in protecting
public health and animal health. The agency also helps assure high
public confidence in our food supply that supports our \$1.3 trillion
annual agricultural economy. The FDA must balance competing interests,
laws, regulations, and international recommendations that appear to
conflict with or may be based on very limited science, especially when
dealing with emerging transmissible spongiform encephalopathy diseases
(TSEs), such as bovine spongiform encephalopathy (BSE/mad cow disease)
that may be transmitted to certain susceptible people who subsequently
present with variant Creutzfeldt-Jakob Disease (vCJD.)

The comments contained herein point to several overarching issues
regarding BSE and protecting public health:

1.  The science on BSE is very limited to date;

2.  There is strong evidence that prions are the infective agent in BSE
    and other TSEs;

3.  Prions are very difficult to destroy compared with other pathogens
    such as bacteria, viruses, and other microorganisms;

4.  Experts agree that meat and bone meal (MBM) is a critical factor in
    the BSE transmission cycle;

5.  Consumption of MBM and/or specified risk materials (SRMs) present
    the greatest risk of transmitting BSE to humans and animals;

6.  FDA must respond to protect U.S. public and animal health and
    economic interests based on what it knows now.

The comments provided here are largely based on presentations made by
experts who participated in a two-day Ceres^®^ Forum on *Transmissible
Spongiform Encephalopathies in Animal and Human Health: the Science and
the Policy.* This conference was held on March 8-9, 2004, and was
convened and organized by the Center for Food and Nutrition Policy.
Support for the conference was provided by the University of
Maryland/FDA Joint Institute for Food Safety and Applied Nutrition; FDA
Center for Veterinary Medicine; FDA Center for Devices and Radiological
Health; the law firm of Covington & Burling; the USDA Cooperative State
Research, Education and Extension Service; and conference registration
fees.

Leading TSE researchers were brought together for two days of "cutting
edge" scientific presentations and probing discussions. Each of these
top researchers individually confirmed that currently there is
relatively little "sound science" on TSEs and prions. This is in large
part because prion research requires:

1.  substantial funding;

2.  a Biosafety Level Three Laboratory (BSL-3)---the same as required
    for anthrax research;

3.  experimental approaches that are labor-intensive, time-consuming,
    and cumbersome;

4.  dedicated expensive laboratory equipment that presumptively becomes
    contaminated with prions; and

5.  lengthy experiments that create great lag times in publishing the
    results.

This final point makes it is difficult for academic researchers to
perform research that results in one publication every three or four
years [and]{.underline} that permanently contaminates expensive
laboratory space and equipment. There is currently relatively little
ongoing TSE and prion research in the U.S. or Canada because of the
above five factors and others.

**[TSE and Prion Research Is in Its Infancy and Is
Under-Funded]{.underline}**

Scientists have studied bacteria since the time of Pasteur in the 1800s
and viruses for 100 years, but prions were only discovered 20 years ago
by Dr. Stanley Prusiner.[^2] The whole prion research field is still in
its infancy and experimental approaches to studying this newly
discovered infective agent are labor-intensive, time-consuming, and
cumbersome.

The rudimentary knowledge of TSEs makes regulatory decisions difficult,
but even more critical. Moreover, leading TSE/prion researchers believe
that significant scientific advances are ten or more years off because
the field is limited by research funding. This area of research has cost
a lot of money to reach this stage of scientific knowledge and it may
cost ten times more to advance. It will require enormous resources, plus
refocused research efforts by scientific and health agencies to
effectively deal with TSE threats and challenges.

The FDA should now put adequate safeguards in place that effectively
limit our public health and financial exposure to this new form of
zoonotic pathogen for the following reasons:

1.  TSEs are invariably fatal neurodegenerative diseases;

2.  the causative agent---prions---are known to persist in the
    environment and are very resistant to many means that kill / destroy
    other known pathogens;

3.  there is cross-species and dam-offspring TSE transmission;

4.  prions are found in a number of tissues of infected animals and
    people, including brain, spinal cord, dorsal root ganglia,
    gastrointestinal tract (especially the distal ileum), and possibly
    muscle and blood; and

5.  the most important route of infectivity appears to be through
    consumption of MBM.

The Center therefore urges FDA not to wait for the "smoking gun"
scientific papers before effectively safeguarding the U.S. economy and
public health from TSEs and prions.

**[Level of BSE in the U.S. Is Unknown]{.underline}**

The only confirmed case of BSE in the United States is a Canadian-born,
Washington state cow that tested positive for the disease last
December.[^3] A July, 2004 report published by the U.S. Department of
Agriculture's (USDA) Inspector General rebuked the department for
numerous problems in its BSE surveillance plan that could have reduced
the chances of finding a positive case in U.S. herds. It is therefore
likely that there is more BSE in the U.S. than currently believed. This
is in part because the USDA failed to test for BSE or collect the
correct portion of the brain on nearly 500 suspect cows over the past
two years---including some in high-risk categories for
infection---according to USDA records obtained by United Press
International.

The Inspector General\'s report faulted the USDA for failing to install
screening procedures to ensure it gets access to the cows most likely to
be infected with the deadly BSE disease. This includes those that test
negative for rabies[^4] and those with central nervous system clinical
signs. The report notes that, in 2002, four cows presenting with central
nervous system clinical signs and 11 rabies-negative cows were not
tested for BSE or the wrong part of the brain was collected. In 2003,
the testing problems appeared to increase, occurring in 10 cows
presenting with central nervous system clinical signs and 38
rabies-negative cattle.

Nearly all of these cattle were older than 30 months---many were 6 to 8
years old---putting them in an age range most likely to test
BSE-positive if they were infected. The USDA\'s current BSE surveillance
plan focuses almost exclusively on animals in this age range because
they are old enough for the slow-incubating disease to have reached
detectable levels in infected animals. The four types of prion tests
that are currently available can only detect the high levels of prions
found late in BSE.[^5]

**[Early Research Suggests Greater vCJD Incidence in the UK
Population]{.underline}**

Currently there are no tests to detect early infection of people with
variant Creutzfeldt-Jakob disease (vCJD), the human form of BSE. London
scientists have found evidence suggesting that a greater proportion of
people could be infected with vCJD than previously thought. In addition,
it now seems possible that some vCJD victims may develop a milder
version of the disease.

As of February, 2004, 146 people have been diagnosed with vCJD in the
U.K., and another 10 have been diagnosed elsewhere. No one knows exactly
how many other people are incubating prions that cause vCJD.
Epidemiological models suggest that only a few dozen more individuals
will develop vCJD, but these models are based on assumptions that may
prove wrong. One assumption, for example, is that vCJD affects only
those with a particular genetic makeup. Because prions incubate for so
long, it will take some time before we know the ultimate number of vCJD
cases and whether they share similar genetics.[^6]

To date, autopsies have diagnosed vCJD only in people with a certain
genetic profile. Research published in the August, 2004, issue of *The
Lancet* medical journal found vCJD in a victim with a more commonplace
genetic signature. For the first time, a person diagnosed with vCJD
displayed no clinical symptoms. This suggests that more people than
previously believed could be incubating vCJD.

This is the first evidence that a major subgroup of humans is
susceptible to vCJD infection. It is possible that the incubation period
for vCJD in this large human population group will be longer than what
we\'ve seen clinically so far. The finding means that forecasts of the
total number of vCJD victims needs to be radically revised. Recent
predictions in fact have ranged widely from 10 more cases to more than
10,000 cases. These estimates assume that vCJD infects only those with
the less common genetic profile and that the incubation period can be as
long as 30 years.

The latest discovery comes from autopsy results of an elderly person
dead from an unrelated cause. The victim received a blood transfusion
five years ago from a donor who later developed and died of vCJD. This
is the second reported case in 2004 that links vCJD to a blood
transfusion, bolstering the hypothesis that vCJD is also transmitted
through blood. The genetic profile in this most recent case was one that
occurs in half of all Caucasians. It is less common among other
ethnicities. [^7]^,^[^8]

**[Lessons from StarLink™ Corn Should Be Applied to an SRM
Ban]{.underline}**

Federal regulators recently learned it is impossible to keep separate
StarLink™ corn from non-GMO corn. Those lessons should be considered in
developing two lists of banned SRMs (one for animals and one for
people). Such action promises similar regulatory failure with
potentially greater economic and public health losses.[^9]

**[Removal of Intestines Should Be As Simple As Possible]{.underline}**

Removal of the intestines as SRM should be kept as simple and as
inclusive as possible so that the currently known prion-infected
portions of intestine will be removed from both animal and human food
chains. It is unlikely that prions are found only in the distal ileum
and not the duodenum, jejunum, the proximal and intermediate ileum, the
cecum, the various parts of the colon and the rectum. It is more likely
that the current insensitive prion tests are not finding them elsewhere
in the gastrointestinal tract---and elsewhere in cattle. If all of the
intestinal tract is required to be removed as an SRM, there will be less
temptation to retain banned portions for use in human foods and products
or for animal foods.

Keeping separate the distal ileum from the rest of the small intestine
and from the proximal portion of the large intestine (including at the
ileocecocolic junction) will most likely also prove impossible. Also,
the limited, sound science keeps adding new tissues to the
ever-expanding list of known or suspected prion-containing tissues.
Prions are believed to infect through the gastrointestinal tract, enter
the bloodstream, and end-up in the central nervous system and other
distant sites.[^10] The entire intestine with its selectively absorptive
mucosa presents a prime avenue for prion entry as they infect cattle.

The USDA recently formed a select committee (the International Review
Team or IRT) of world-recognized BSE experts[^11] with more than 60
years of cumulative, professional expertise to guide the USDA in
regulating BSE. Based solely on the current sound science, the IRT
believes that the entire intestine must be banned from animal and human
food in order to safeguard the U.S. economy and public health.

William Hueston, DVM, PhD, Director of the Center for Animal Health and
Food Safety at the University of Minnesota and a member of the recent
IRT delivered the presentation "The Report on Measures Relating to BSE
in the U.S." during the March Ceres Forum in which he stated:

> "... The committee (International Review Subcommittee of the USDA
> Secretary's Advisory Committee on Foreign Animal and Poultry Disease)
> feels strongly that surveillance is not a public health measure. **The
> public health measure is the SRMs ban from the human food supply.**
> ...
>
> **We recommend all SRMs be banned from all animal feeds.** This will
> remove infectivity from the feed supply to compensate for feed ban
> leaks. **It provides a preventive redundancy while recognizing the
> logistic problems of handling the volume of SRMs.** \...
>
> **The second recommendation excludes all mammalian and poultry
> proteins from ruminant feeds until there are test protocols assuring
> no ruminant proteins are fed to ruminants.** The group believes there
> is an opportunity to look for innovative solutions to the safe,
> environmentally responsible use of SRMs that captures their value. An
> economically viable solution would help get SRMs out of animal and
> human feeds. ...
>
> BSE has spread globally by moving infected animals and animal
> products. Protection of the public health is achieved through the SRM
> ban with the prevention of cross-contamination. **Animal health
> protection requires blocking the recycling of BSE prions through
> animal feeds.** The use of surveillance to monitor the implementation
> of these initiatives---and targeting surveillance to high-risk
> cattle---achieve the most protections. ..."

The Center therefore concludes that the list of SRMs must be the same
for human and animal foods.

**[Research Shows Infective Dose Is Low]{.underline}**

The limited sound science regarding the infectious nature of TSE-causing
prions continues to lower the infectious dose as more research is
reported in peer-reviewed scientific journals. Recent U.K. studies
report that as little as 10 milligrams or less of BSE-infected bovine
brain tissue cause disease in some exposed cattle. In 2004, the U.K. has
reported two cases where people are believed to have contracted vCJD
from blood transfusions received years earlier from people infected with
vCJD. BSE prions are primarily transmitted through the gastrointestinal
route, which includes the large intestine. There may be a human
infectious dose of BSE prions in many bovine tissues not yet detectable
because of the four types of insensitive prion tests. The large
intestine---as part of the gastrointestinal tract---may well be another.

William Hueston, DVM, PhD, Director of the Center for Animal Health and
Food Safety at the University of Minnesota and a member of the recent
International review Team (IRT) gave the presentation "The Report on
Measures Relating to BSE in the U.S." in which he stated:

> "...The second recommendation excludes all mammalian and poultry
> proteins from ruminant feeds **until there are test protocols assuring
> no ruminant proteins are fed to ruminant.** ...
>
> The existing feed ban has already had a large impact, but can not
> prevent all BSE exposure of cattle. UK challenge studies data
> demonstrate that 10 milligrams or less of BSE-infected bovine brain
> tissue causes disease in some exposed cattle. The cross‑contamination
> risk is documented in many situations in Europe. **We currently do not
> have the technology to test feeds commercially.** ...
>
> We recommend all SRMs be banned from all animal feeds. This will
> remove infectivity from the feed supply to compensate for feed ban
> leaks. **It provides a preventive redundancy** ...
>
> The second recommendation excludes all mammalian and poultry proteins
> from ruminant feeds **until there are test protocols assuring no
> ruminant proteins are fed to ruminants.** ... "

The Center therefore urges FDA to follow the International Review Team's
expert opinion (which is based on the current sound science) that all of
the intestine be removed to prevent potentially infective material from
entering the human food and animal feed chains. Moreover, only dedicated
processing facilities with stringent, strictly enforced penalties will
ensure that cross-contamination will (most likely) not occur. The
materials containing SRMs should be visually distinguishable from those
free of SRMs to prevent accidental and/or intentional confusion in
identifying SRM-containing feeds that results in feeding SRM-containing
materials to people and/or animals.

The proposals in these comments are in no way based on the much-debated
"precautionary principle." The precautionary principle is applied when
no risk has been demonstrated but there is still uncertainty in a risk
assessment. For example, the precautionary principle has been invoked to
restrict trade in hormone-treated beef and biotech crops. In the case of
BSE, the economic risks and the risks to medical products have been
clearly demonstrated in the U.K. and other countries, even if the
overall food safety risk is small. The existence of risk from BSE and
other TSEs is not uncertain---it is known and potentially devastating.
Prudent steps are required to manage that risk while science continues
to advance our understanding of the nature of TSEs.

The FDA should protect our national economy and public health with
effective regulations at least until the "sound science" that is now
some ten years off sheds much more intellectual light on TSEs and
prions.

**[Human Error and Prion Hardiness Can Create Problems of
Cross-Contamination]{.underline}**

The human factor in processing and distributing feed materials---and the
tremendous resistance of prions to ordinary means of disinfection /
destruction---ttogether dictate that the only way to prevent
cross-contamination is with totally‑dedicated facilities, equipment,
storage, and transportation.

The pathogenic prions tend to form difficult-to-dissolve clumps that
resist heat, radiation, and chemicals that would kill other pathogens. A
few minutes of boiling wipes out bacteria, viruses and molds, but not
pathogenic prions. Prions are transmitted to cattle through meat and
bone meal. High heat eliminates conventional pathogens, but pathogenic
prions survive to infect cattle.

Each new scientific report about TSEs and/or prions indicates that
prions are more infectious and hardy than previously believed.
Facilities, equipment, storage, and transportation already used for
SRM-containing materials most likely cannot be effectively disinfected
of prions because of their highly resistant nature.

With the unwavering trend of discouraging scientific knowledge trickling
out from even the best TSEs/prion research laboratories, dedicated
facilities, equipment, storage, and transportation for materials that
contain SRMs are needed to prevent cross-contamination with materials
that do not contain SRMs.

Dr. Stanley Prusiner's laboratory published a peer-reviewed paper
reporting prions in skeletal muscle of transgenic mice with the cattle
gene for prions. Other researchers in the U.S. and elsewhere have also
reported finding prions in the skeletal muscle of other animals and of
people dead from vCJD.[^12] Prions in ruminant skeletal muscle used for
MBM feeds will require dedicated rendering and mixing facilities,
equipment, storage, and transportation to prevent cross-contamination of
rendered products used in animal feeds.

In addition, the IRT noted that the cross-contamination risk is
documented in many situations in Europe and there is no technology to
test feeds commercially.

The Center urges FDA to require dedicated rendering and mixing
facilities, equipment, storage, and transportation even if the FDA bans
SRMs in animal feeds.

**[All Four Types of Tests for BSE Prions Are Insensitive and
Unsatisfactory]{.underline}**

Current prion tests are insensitive and can detect only dense prion
populations. Cattle do not usually demonstrate BSE clinical signs until
they are more than five years old. Most cattle consumed as beef are
slaughtered before they reach 30 months of age.[^13] Very little active
prion research is searching for prions in the many other bovine tissues
used for human consumption and products.

The very limited scientific information concerning TSEs and prions is
sufficient to clearly demonstrate that we have no effective,
commercially-practicable methods to destroy prions during any
"clean-out" of animal feed processing / mixing equipment. Even small
human surgical instruments cannot be effectively cleaned of prions
without destroying the instruments in the process.

As little as 10 mg of infectious material can infect a cow with BSE.
None of the available four types of tests for prions (bioassay,
immunohistochemistry, immunoassay, and conformation-dependent
immunoassay \[CDI\]) can determine if animal feed processing / mixing
equipment is free of prion contamination:

Each of these four types of tests is inherently insensitive and can
detect pathogenic prions only in BSE--infected brain with dense prion
populations. These rapid tests, however, have limitations. They depend
on pathogenic prions accumulating to detectable amounts---quite often,
relatively high levels---in an animal's brain. Yet because BSE often
takes three to five years to develop, most slaughter-age cattle, which
tend to be younger than two years, usually do not test positive, even if
they are infected. Therefore, these tests are generally most reliable
for older bovines, regardless of whether they look healthy or are
"downers." At the moment, downer cattle, which cannot stand on their
own, are the group most likely to be tested.

The Center is not aware of any tests to determine if a feed has
materials (SRMs or others) from dead stock and non-ambulatory disabled
cattle.

**[Prions Have Been Detected in Skeletal Muscle and Blood]{.underline}**

Dr. Patrick Bosque, now at the University of Colorado's Health Sciences
Center, and Dr. Prusiner found prions in the hind limb skeletal muscles
of mice at a level 100,000 times as high as that found in blood. Other
muscle groups had prions as well, but at much lower levels. Dr. Michael
Beekes and colleagues at the Robert Koch Institute in Berlin discovered
pathogenic prions in virtually all muscles after they fed pathogenic
prions to hamsters. They reported high levels of prions in all muscles,
not just in the hind limbs. These findings were also reported in human
patients. U.C.S.F. scientists Safar and DeArmond reported pathogenic
prions in the muscles of some CJD patients. Dr. Adriano Aguzzi and
colleagues at the University of Zurich identified pathogenic prions in
the muscles of 25 percent of the CJD patients they examined. Whether
milk can be affected with BSE prions remains open, but is being actively
researched by Dr. Stanley Prusiner's laboratory at UCSF.

CFNP concludes that "clean-out" would not provide adequate protection
against cross-contamination even if SRMs are excluded from all animal
feed. There are no tests available to determine if any "clean-out" has
rid the "cleaned-out" equipment of pathogenic prions. There is credible
scientific evidence that pathogenic prions are also found in skeletal
muscles of animals affected with TSEs. Excluding all currently
recognized SRMs from all animal feeds would not necessarily eliminate
pathogenic prions from the animal food chain.

Animal studies have shown that prions can be transmitted to healthy
animals through blood transfusions from infected animals causing many
nations to enact stricter blood donation rules. In the U.K., people born
after 1996 (when the tough feed ban came into force) can receive blood
only from overseas because those people born before 1996 are considered
already exposed to pathogenic prions that cause BSE in cattle and vCJD
in people. In the U.S., those who spent three months or more in the U.K.
between 1980 and 1996 cannot give blood. Pathogenic prions that cause
vCJD build up in the brain and the lymphoid system including the tonsils
and appendix. These are part of the gastrointestinal tract, which is the
main natural infective route for pathogenic prions in animals and
people. This suggests that pathogenic prions enter the bloodstream at
some point.

In December, 2004, the U.K. announced the vCJD death of one of 15 people
who received blood transfusions from donors who themselves later
developed vCJD. The victim received the blood transfusion seven and a
half years before dying. The victim's age argues against being infected
by consuming prion‑tainted food. He was 69 years old and the typical
vCJD victim is about 29 years old. It is likely that vCJD is not limited
to those who have eaten prion-infected beef.[^14]

There are recent British reports that BSE prions are transferred in
human blood transfusions that can cause vCJD in the recipients many
years later. Until the scientific community learns otherwise, the FDA
must presume that there is some risk that cattle blood may transmit BSE
to cattle and other animals. However, far more research is needed in
this area.

Dr. Stanley Prusiner's laboratory published a scientific paper reporting
prions in the skeletal muscle of experimental mice. At least three new
TSEs (BSE, vCJD, and CWD) caused by the pathogenic prions that cause
scrapie in sheep are believed to have jumped from a sheep where it
resided for more than 250 years to several new species. These include
cattle, people, domestic felidae, zoo felidae, nonhuman primates, wild
ungulates, plus wild and domestic cervids in just the past 40-plus
years.

There are other scientific papers that report prions from a susceptible
species can pass through a non-susceptible species---or accumulate in
that non-susceptible species---and then infect the original species with
prion disease. Poultry litter may accumulate the BSE prions that pass
through birds that consume BSE prions found in poultry feeds made from
cattle skeletal muscle and other tissues.

The Center urges FDA to prohibit SRMs from being used in animal feed and
prohibit the use of poultry litter in ruminant feed.

**[Summary]{.underline}**

The Center urges FDA to:

1)  ban all SRMs from all animal and human feeds and products, and the
    SRM list should be the same for human and animal feeds and products;

2)  follow the International Review Team's expert opinion (that is based
    on the current sound science) that all of the intestine be removed
    to prevent potentially infective material from entering the human
    food and animal feed chains;

3)  even if FDA bans all SRMs from all products, require dedicated
    rendering and mixing facilities. Facilities that process SRMs for
    industrial products must be dedicated solely for that purpose since
    "clean out" is not sufficient;

4)  encourage further research to assess the possible risk to other
    animals from prions in cattle blood and blood products; and

5)  encourage more research to determine if cattle skeletal muscle and
    blood pose a risk of transmission or amplification if these
    materials are used for animal feeds.

Respectfully submitted,

![](media/image2.jpeg){width="2.4791666666666665in"
height="0.5416666666666666in"}![](media/image3.jpeg){width="1.9909722222222221in"
height="0.6479166666666667in"}

Maureen L. Storey, PhD Richard A. Forshee, PhD

Director, CFNP Associate Director, CFNP

Director, Research

![](media/image4.jpeg){width="1.9340277777777777in"
height="1.2368055555555555in"}

Gary A. Weaver, DVM, PhD, Esq

Adjunct, National Capital Region

Senior Fellow, CFNP

[^1]: Federal Register: Proposed Rules. July 14, 2004, Volume 69, Number
    134, pages 42287-42300.

    <http://a257.g.akamaitech.net/7/257/2422/06jun20041800/edocket.access.gpo.gov/2004/04-15882.htm>

[^2]: Dr. Stanley Prusiner was awarded the Nobel Prize for his prion
    research and remains the world's foremost prion scientific expert.

[^3]: "No Mad Cow Results for Nearly 500 Cows," Steve Mitchell. United
    Press International

    Published 8/11/2004 11:23 AM Steve Mitchell is UPI\'s Medical
    Correspondent.

    E-mail: <sciencemail@upi.com>

[^4]: Rabid cattle oftentimes present with non-specific central nervous
    signs similar to those presented by cattle with BSE. In many cases
    the clinical signs of rabies in cattle will be indistinguishable
    from those of BSE in cattle.

[^5]: "No Mad Cow Results for Nearly 500 Cows," Steve Mitchell. United
    Press International

    Published 8/11/2004 11:23 AM by Steve Mitchell, Medical
    Correspondent. E-mail: <sciencemail@upi.com>

[^6]: "Detecting Mad Cow Disease." Stanley Prusiner. *Scientific
    American,* July, 2004. pp. 86-93.

[^7]: "Research Hints at a Wider Human Spread of Mad Cow." International
    Herald Tribune.

    August 7, 2004.
    [[http://www.iht.com/cgi-bin/search.cgi?key=LONDON]{.underline}](http://www.iht.com/cgi-bin/search.cgi?key=LONDON)

[^8]: "Preclinical vCJD After Blood Transfusion in a PNRP codon 129
    Heterozygous Patient." Peden, A. H., *et al.* *The Lancet* 2004;
    264: pp 527-29.

[^9]: "StarLink™ Corn Controversy: Background." CRS Report for Congress.
    National Council for Science and the Environment, 1725 K Street,
    Suite 212 - Washington, DC 20006 <info@NCSEonline.org>

[^10]: "Detecting Mad Cow Disease" by Stanley Prusiner. *Scientific
    American,* July, 2004. pp. 86-93.

[^11]: Prior to the conclusion of the epidemiological investigation, on
    January 22-24, 2004, the Secretary of Agriculture convened an
    international panel of experts to assess the epidemiological
    investigation, provide expert opinion as to when the active phase
    should be terminated, consider the response actions of the United
    States to date, and provide recommendations as to actions that could
    be taken to provide additional meaningful human or animal health
    benefits in light of the North American experience. The
    international review team was organized as a subcommittee of the
    Secretary of Agriculture\'s Foreign Animal and Poultry Disease
    Advisory Committee. The subcommittee consisted of Prof. U. Kihm
    (Switzerland), Prof. W. Hueston (USA), Dr. D. Matthews (UK), Prof.
    S. C. MacDiarmid (New Zealand), and Dr. D. Heim (Switzerland). The
    subcommittee (referred to below as the IRT) provided its report on
    February 4, 2004. The complete report, \`\`Report on Measures
    Relating to BSE in the United States,\'\' is available for viewing
    at
    [http://www.aphis.usda.gov/lpa/issues/bse/BSE_tr_ban_ltr%20_enc_2.pdf](http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://www.aphis.usda.gov/lpa/issues/bse/BSE_tr_ban_ltr _enc_2.pdf).

[^12]: "Detecting Mad Cow Disease." Stanley Prusiner. *Scientific
    American,* July, 2004. pp. 86-93.

[^13]: *Ibid*

[^14]: "Detecting Mad Cow Disease." Stanley Prusiner. *Scientific
    American*, July, 2004. pp. 86-93.