US "Atypical" Mad Cow Threat Was Predicted

by John Stauber — June 14, 2006 - 10:33am

Topics: Mad Cow Disease, Food Safety, Agriculture, Science

Did the U.S. Infect Europe with Atypical Mad Cow Disease?

The discovery that the Texas and Alabama BSE cases are a variant strain identical to EU cases begs the question of whether the atypical EU cases resulted from European cattle being fed infected US feed made from rendered by-products and sold in Europe. After all, the US has been the biggest creator, user and exporter of by-product feed made from slaughterhouse waste. Also, scientists need to examine the TSE isolated by Richard Marsh in mink and traced to Wisconsin cattle, and compare it to the atypical BSE strain found in Texas, Alabama, France, Poland, Germany and Sweden. Is the Stetsonville TSE strain discovered by Richard Marsh the same strain as the US and EU atypical BSE cases, or is it another atypical strain?

Here below is our report on Marsh's discovery in 1985 of an atypical strain of BSE in US cattle from our 1997 book Mad Cow USA. (You can order the book for free from your favorite library and it is for sale in the usual places.)

Mad Cow USA

(The following excerpt is from Mad Cow USA, by Sheldon Rampton and John Stauber, pages 154-156:)

The common denominator in all of these [transmissible mink encephalopathy - TME] outbreaks was either "cattle" or "unknown." It was possible, of course, to imagine other scenarios, but Marsh believed he had at least strong circumstantial evidence that a TSE similar to mad cow disease already existed in U.S. cattle. "You can trace it back to feed real easy in mink," Marsh said. "And then you're left with the question, what was it in the feed that affected them? And what we find is it's these downer cows that are the common link. You don't have to be a genius to figure it out."

Within the field of veterinary medicine, "downer cow syndrome" was a "garbage can" category, used indiscriminately as the official diagnosis for any animal that died or had to be put down after failing to stand on its own legs for 24 hours or more. These included cows suffering from paralysis, arthritis, grass tetany, ketosis, bone fractures, and a form of calcium deficiency known as "milk fever." Most downer cows died from causes unrelated to the spongiform encephalopathies, but it was possible that the generic nature of the classification enabled some TSE-infected cows to slip into the mix.

It was impossible in practice to absolutely prove the link between downer cows and transmissible mink encephalopathy. By the time the disease appeared in mink, any cow that might have been the source would be long gone, its tissues unavailable for testing. To test his theory, therefore, Marsh did the next best thing—a series of experiments using brain matter from one of the mink that had died in the Stetsonville outbreak. He puréed the brain in a blender and used hypodermic syringes to inject the homogenized liquid into test animals: fourteen healthy mink, eight ferrets, two squirrel monkeys, twelve hamsters, forty-five mice and two Holstein bull calves.

The mice, remarkably, all stayed healthy, but every other species proved susceptible. The mink went down first, four months after inoculation. The two monkeys were the next to show neurological signs, at months nine and thirteen respectively. Two of the twelve hamsters survived, but the other ten succumbed in the fifteenth and sixteenth months. The two calves went down in months eighteen and nineteen. The ferrets lasted longest, but eventually the disease emerged in all but one of them, with incubation periods ranging between twenty-eight and thirty-eight months. These species barrier effects corresponded closely to the results from experiments with previous mink outbreaks.

Cattle are expensive test animals, and Marsh's experiments marked the first time that cattle had been tested for susceptibility to transmissible mink encephalopathy. His results proved that cattle could get the mink disease, and in turn led to unexpected new questions. "The real surprise of this experiment is that the clinical signs were quite different from what we've seen in Great Britain," he said. "This is what's changed our perspective on a surveillance of BSE in the United States. We thought BSE in the U.S. would look like BSE in Great Britain—a mad cow type of disease where the animal would have behavioral changes, become aggressive and look very much like a rabies infection does in cows."

Marsh's bull calves showed none of the unusual "mad" behavior that emerged as early warning signs in British cattle. "Eighteen months after inoculation, one animal simply collapsed in its holding room and could not be returned to a standing position," he reported. "This animal had shown no previous signs of behavioral change or loss of body condition. . . . The second animal was normal until nineteen months after inoculation when it too suddenly collapsed."

Indeed, the test bulls behaved exactly like downer cows—the type of animals which the Stetsonville rancher had been feeding to his mink. "The most disturbing finding of all is that they have very minimal spongiform lesions in their brains," Marsh said. In previous experiments with mink, he had shown that the spongy holes in brains were a secondary effect of the disease which did not always appear in noticeable quantities. Some mink breeds infected with TME would develop all of the usual clinical symptoms, but upon autopsy their brains showed a marked lack of spongiform degeneration. Now it appeared that cattle could also develop a form of TSE without the telltale lesions to aid in diagnosis. Their symptoms would look like downer cow syndrome, and even a brain autopsy might find nothing out of the ordinary.

"Without the brain lesions, the best way to diagnose the infection is a protein in the brain," Marsh said. "But there are only a few labs in the country that can look for this protein. This is not something that can be done by the local veterinarian or even most state diagnostic laboratories. You need to have pretty sophisticated means of testing. This is going to complicate our efforts at surveillance and testing for BSE in this country."

Histopathology and immunohistochemistry tests confirmed that Marsh's bulls had died of a spongiform encephalopathy, but it was a different strain of spongiform encephalopathy than the one that was killing cows in England. Its behavior in test animals showed significant differences also. In England, mice succumbed when exposed to brain tissue from mad cows, but hamsters seemed immune. In Marsh's experiments with the Stetsonville isolate of TME, the pattern was exactly the opposite: mice lived, but hamsters died.

From Mad Cows to Mad Mink and Back

To test whether passage through cattle altered the characteristics of the Stetsonville isolate, Marsh injected another 45 mice with brain tissue from his two test bulls. They also stayed healthy, just like the mice he had previously injected with mink brains. By itself, the fact that mink encephalopathy could infect cows was not terribly significant or surprising. After all, scientists had previously shown that TME could be transmitted to a wide variety of other test animals. What was significant was the result when Marsh took the brains of the dead bulls and used them on further tests with healthy mink. When backpassaged into mink, the bull brains behaved exactly the way mink brains behaved, causing symptoms of TME to emerge within four months after exposure by inoculation, or within seven months after oral exposure.

"There was no evidence for any deadaptation of the bovine agent for mink compared to . . . non-bovine-passaged mink brain," Marsh observed. "This suggests that there are no species barrier effects between mink and cattle in relation to the Stetsonville source of TME" — more evidence pointing to cattle as the source of the infection. "If mink on the Stetsonville ranch were exposed to TME by feeding them infected cattle, there must be an unrecognized scrapie-like disease of cattle in the United States," Marsh concluded. "If this is true, the disease is rare. The low incidence rate of TME and the fact that the Stetsonville mink rancher had fed products from fallen or sick cattle to his animals for the past 35 years suggests a very low prevalence of this disease."

The rarity of the disease, however, did not mean that it posed no danger. In fact, it could mean the very opposite. Mad cow disease had also been rare once in England. The very fact that it was rare, combined with its slow incubation period, were the factors that prevented the British from recognizing its dangers until it had already infected tens of thousands of animals. Moreover, the British had an advantage that U.S. farmers might not enjoy. Their strain of bovine spongiform encephalopathy was picked up fairly soon once cattle started behaving strangely. If a different strain of BSE existed in U.S. cattle— a strain where the animals didn't act deranged but simply fell over, like the cows in Marsh's tests—the disease could conceivably go unrecognized for a long time, invisible within the larger population of U.S. downer cows.

Every year, some 100,000 U.S. cows get classified as downers. Marsh was not suggesting that all 100,000 were carriers of a spongiform encephalopathy. What concerned him was the possibility that downer cow syndrome could mask the emergence of a TSE in the cattle population, allowing the disease to invisibly spread until it reached dangerous levels. It could multiply the same way it had multiplied in England, as rendering plants recycled the infection by converting sick animals into meat and bone meal which was then fed back to other cattle. The only certain way to prevent a cattle epidemic, therefore, would be to adopt the same policy that the British had already been forced to adopt: ban the practice of feeding rendered cows and other ruminant animals back to members of their own species.

### (End of excerpt)

How to Hide a Mad Cow

Today the ability to test cattle for mad cow disease has greatly advanced, and so-called rapid tests are used on all cattle before they are allowed into the human food chain in Japan, for example. I describe the situation in the United States as a cover-up of the extent of mad cow disease because the US needs to test millions of cattle a year, and in a transparent and verifiable way, before we can know with accuracy how much disease is present in the US herd. Currently the US is testing less than 1% of its cattle a year, and the procedures are shrouded in secrecy. The US forbids anyone but the government to conduct tests in the United States making it impossible for Americans to purchase meat that has been tested and found free of the disease.

In addition, despite the false PR assurances from government and the livestock industry, there is no "firewall feed ban" in the United States to completely stop the spread of mad cow disease. Today it is legal and widespread to feed US cattle on cattle fat contaminated with cattle protein, on cattle blood, and on poultry shit and litter contaminated with cattle protein. In addition, slaughterhouse waste from cattle is fed to pigs, and in turn the slaughterhouse waste from pigs is fed back to cattle.

We now know we have "atypical" mad cow disease in the US and even the USDA admits that it has probably been spreading for at least a decade through feeding cattle to cattle. Yet, the cannibal feeding practices continue and the US's mad cow testing program is a farce.

Dick Marsh died in 1997 before our book Mad Cow USA was published. He was a careful scientist who understood the precautionary principle and who worked tirelessly and was terribly and personally attacked for his prescient warnings that a unique strain of mad cow disease already existed in the US, and that unless the dangerous feeding practices of cow cannibalism were stopped, it would spread through cattle and threaten human health.

Perhaps if cancer had not silenced Dick Marsh a decade ago, his strong voice would have helped change the current dangerous policies of the United States Department of Agriculture (USDA) and the Food and Drug Administration (FDA). Currently these federal agencies are threatening animal and human safety in the US simply so the US government can protect and preserve the livestock industry's deadly but lucrative practice of animal cannibalism, turning slaughterhouse waste into cheap feed for cattle and other livestock.

Comments

How the California cow got

Submitted by Terry S. Singeltary Sr. (not verified) on May 1, 2012 - 9:25am.

How the California cow got the disease remains unknown. Government officials expressed confidence that contaminated food was not the source, saying the animal had atypical L-type BSE, a rare variant not generally associated with an animal consuming infected feed. However, a BSE expert said that consumption of infected material is the only known way that cattle get the disease under natural conditons. “In view of what we know about BSE after almost 20 years experience, contaminated feed has been the source of the epidemic,” said Paul Brown, a scientist retired from the National Institute of Neurological Diseases and Stroke. BSE is not caused by a microbe. It is caused by the misfolding of the so-called “prion protein” that is a normal constituent of brain and other tissues. If a diseased version of the protein enters the brain somehow, it can slowly cause all the normal versions to become misfolded. It is possible the disease could arise spontaneously, though such an event has never been recorded, Brown said.

http://www.washingtonpost.com/national/health-science/case-of-mad-cow-disease-found-in-california-animal-but-food-supply-said-safe/2012/04/24/gIQAtelqfT_story.html

counterpart: Creutzfeldt-Jakob disease (CJD). In a statement released on 24 April, Karen Ross, Secretary of the California Department of Food and Agriculture said, “The detection of BSE shows that the surveillance program in place in California and around the country is working.” Food safety advocates such as Yonkers, New York, -based Consumers Union say it’s a warning sign that surveillance is inadequate and needs to be stepped up. Ross’s statement also makes a point of noting a key feature of this particular case: The infected cow carried what is known as ‘L-type’ BSE, a version of the disease that has not been detected before in the US and has so far not been associated with transmission through animal feed. As the policy debate over testing rumbles on, here is a short guide to what is known and not known about this rare strain and its unexpected appearance.

http://blogs.nature.com/news/2012/04/california-bse-prion-comes-with-a-different-twist.html

STATEMENT FROM CDFA SECRETARY KAREN ROSS ON USDA ANNOUNCEMENT OF DETECTION OF BSE Release #12-016 Print This Release SACRAMENTO, April 24, 2012 – CDFA Secretary Karen Ross issued this statement following the USDA’s announcement of the detection of atypical bovine spongiform encephalopathy (BSE) in a California dairy cow: “The detection of BSE shows that the surveillance program in place in California and around the country is working. Milk and beef remain safe to consume. The disease is not transmitted through milk. Because of the strength of the food protection system, the cow did not enter the food or feed supply. There are numerous safeguards in place to prevent BSE from entering the food chain. “The atypical BSE designation is important because this is a very rare form of BSE not generally associated with an animal consuming infected feed. CDFA veterinarians are working with the USDA to investigate this case and to identify whether additional cows are at risk. Feed restrictions in place in California and around the country for the last 15 years minimize that risk to the greatest degree possible. We will provide additional information about this case as it becomes available.” The USDA announcement may be viewed at:

http://www.usda.gov/wps/portal/usda/usdahome?contentid=2012/04/0132.xml&contentidonly=true http://www.cdfa.ca.gov/egov/Press_Releases/Press_Release.asp?PRnum=12-016

CDC - Bovine Spongiform Encephalopathy and Variant Creutzfeldt ... Dr. Paul Brown is Senior Research Scientist in the Laboratory of Central Nervous System ... Address for correspondence: Paul Brown, Building 36, Room 4A-05, ...

http://www.cdc.gov/ncidod/eid/vol7no1/brown.htm

CDC DR. PAUL BROWN TSE EXPERT COMMENTS 2006 In an article today for United Press International, science reporter Steve Mitchell writes: Analysis: What that mad cow means By STEVE MITCHELL

UPI Senior Medical Correspondent WASHINGTON, March 15 (UPI) -- The U.S. Department of Agriculture was quick to assure the public earlier this week that the third case of mad cow disease did not pose a risk to them, but what federal officials have not acknowledged is that this latest case indicates the deadly disease has been circulating in U.S. herds for at least a decade. The second case, which was detected last year in a Texas cow and which USDA officials were reluctant to verify, was approximately 12 years old. These two cases (the latest was detected in an Alabama cow) present a picture of the disease having been here for 10 years or so, since it is thought that cows usually contract the disease from contaminated feed they consume as calves. The concern is that humans can contract a fatal, incurable, brain-wasting illness from consuming beef products contaminated with the mad cow pathogen. "The fact the Texas cow showed up fairly clearly implied the existence of other undetected cases," Dr. Paul Brown, former medical director of the National Institutes of Health's Laboratory for Central Nervous System Studies and an expert on mad cow-like diseases, told United Press International. "The question was, 'How many?' and we still can't answer that." Brown, who is preparing a scientific paper based on the latest two mad cow cases to estimate the maximum number of infected cows that occurred in the United States, said he has "absolutely no confidence in USDA tests before one year ago" because of the agency's reluctance to retest the Texas cow that initially tested positive. USDA officials finally retested the cow and confirmed it was infected seven months later, but only at the insistence of the agency's inspector general. "Everything they did on the Texas cow makes everything they did before 2005 suspect," Brown said. Despite this, Brown said the U.S. prevalence of mad cow, formally known as bovine spongiform encephalopathy, or BSE, did not significantly threaten human or cattle health. "Overall, my view is BSE is highly unlikely to pose any important risk either in cattle feed or human feed," he said. However, Jean Halloran of Consumers Union in Yonkers, N.Y., said consumers should be troubled by the USDA's secrecy and its apparent plan to dramatically cut back the number of mad cow tests it conducts. "Consumers should be very concerned about how little we know about the USDA's surveillance program and the failure of the USDA to reveal really important details," Halloran told UPI. "Consumers have to be really concerned if they're going to cut back the program," she added. Last year the USDA tested more than 300,000 animals for the disease, but it has proposed, even in light of a third case, scaling back the program to 40,000 tests annually. "They seem to be, in terms of actions and policies, taking a lot more seriously the concerns of the cattle industry than the concerns of consumers," Halloran said. "It's really hard to know what it takes to get this administration to take action to protect the public." The USDA has insisted that the safeguards of a ban on incorporating cow tissue into cattle feed (which is thought to spread the disease) and removal of the most infectious parts of cows, such as the brain and spinal cord, protect consumers. But the agency glosses over the fact that both of these systems have been revealed to be inadequately implemented. The feed ban, which is enforced by the Food and Drug Administration, has been criticized by the Government Accountability Office in two reports, the most recent coming just last year. The GAO said the FDA's enforcement of the ban continues to have weaknesses that "undermine the nation's firewall against BSE." USDA documents released last year showed more than 1,000 violations of the regulations requiring the removal of brains and spinal cords in at least 35 states, Puerto Rico and the Virgin Islands, with some plants being cited repeatedly for infractions. In addition, a violation of similar regulations that apply to beef exported to Japan is the reason why Japan closed its borders to U.S. beef in January six weeks after reopening them. Other experts also question the adequacy of the USDA's surveillance system. The USDA insists the prevalence of mad cow disease is low, but the agency has provided few details of its surveillance program, making it difficult for outside experts to know if the agency's monitoring plan is sufficient. "It's impossible to judge the adequacy of the surveillance system without having a breakdown of the tested population by age and risk status," Elizabeth Mumford, a veterinarian and BSE expert at Safe Food Solutions in Bern, Switzerland, a company that provides advice on reducing mad cow risk to industry and governments, told UPI. "Everybody would be happier and more confident and in a sense it might be able to go away a little bit for (the USDA) if they would just publish a breakdown on the tests," Mumford added. UPI requested detailed records about animals tested under the USDA's surveillance plan via the Freedom of Information Act in May 2004 but nearly two years later has not received any corresponding documents from the agency, despite a federal law requiring agencies to comply within 30 days. This leaves open the question of whether the USDA is withholding the information, does not have the information or is so haphazardly organized that it cannot locate it. Mumford said the prevalence of the disease in U.S. herds is probably quite low, but there have probably been other cases that have so far gone undetected. "They're only finding a very small fraction of that low prevalence," she said. Mumford expressed surprise at the lack of concern about the deadly disease from American consumers. "I would expect the U.S. public to be more concerned," she said. Markus Moser, a molecular biologist and chief executive officer of Prionics, a Swiss firm that manufactures BSE test kits, told UPI one concern is that if people are infected, the mad cow pathogen could become "humanized" or more easily transmitted from person to person. "Transmission would be much easier, through all kinds of medical procedures" and even through the blood supply, Moser said.

http://www.upi.com/ConsumerHealthDaily/view.php?StoryID=20060315-055557-1284r http://www.upi.com/Science_News/2003/12/30/Mad-Cow-Linked-to-thousands-of-CJD-cases/UPI-47861072816318/

PAUL BROWN COMMENT TO ME ON THIS ISSUE

Tuesday, September 12, 2006 11:10 AM

\
"Actually, Terry, I have been critical of the USDA handling of the mad cow issue for some years, and with Linda Detwiler and others sent lengthy detailed critiques and recommendations to both the USDA and the Canadian Food Agency."

OIE says the animal was sub-clinical ;

http://web.oie.int/wahis/public.php?page=single_report&pop=1&reportid=11893

also, officials have confirmed it was a atypical L-type BASE BSE. I am deeply disturbed about the false and terribly misleading information that is being handed out by the USDA FDA et al about this recent case of the atypical L-type BASE BSE case in California. these officials are terribly misinformed (I was told they are not lying), about the risk factor and transmissibility of the atypical L-type BASE BSE. these are very disturbing transmission studies that the CDC PUT OUT IN 2012. I urge officials to come forward with the rest of this story. It is important to reiterate here, even though this animal did not enter the food chain, the fact that the USA now finds mad cow disease in samplings of 1 in 40,000 is very disturbing, and to add the fact that it was an atypical L-type BASE BSE, well that is very disturbing in itself. 1 out of 40,000, would mean that there were around 25 mad cows in the USA annually going by a National herd of 100 million (which now I don’t think the USA herd is that big), but then you add all these disturbing factors together, the documented link of sporadic CJD cases to atypical L-type BASE BSE, the rise in sporadic CJD cases in the USA of a new strain of CJD called ‘classification pending Creutzfeldt Jakob Disease’ cpCJD, in young and old, with long duration of clinical symptoms until death. the USA has a mad cow problem and have consistently covered it up. it’s called the SSS policy. ...

see full text with updated transmission studies and science on the atypical L-type BASE BSE Jan. 2012 CDC. ...

***Oral Transmission of L-type Bovine Spongiform Encephalopathy in Primate Model

***Infectivity in skeletal muscle of BASE-infected cattle

***feedstuffs- It also suggests a similar cause or source for atypical BSE in these countries.

***Also, a link is suspected between atypical BSE and some apparently sporadic cases of Creutzfeldt-Jakob disease in humans.

now, for the rest of the story, the most updated science on the atypical BSE strains, and transmission studies...

Thursday, April 26, 2012

Update from USDA Regarding a Detection of Bovine Spongiform Encephalopathy (BSE) in the United States WASHINGTON bulletin at 04/26/2012 10:11 PM EDT

http://transmissiblespongiformencephalopathy.blogspot.com/2012/04/update-from-usda-regarding-detection-of.html

kind regards, terry

Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas, USA 77518 flounder9@verizon.net

I think the Miami and Canadian cannibal should be tested.

Submitted by jerryn (not verified) on June 7, 2012 - 8:21am.

I am starting to think that the cases in Miami, USA and Canada are related.
I hope the authorities are smart enough to have a biopsy done to check for a prion infection. Also there was a madman in Warwick ,RI last night that stripped naked, ran around making primal screams in the RI Mall, eventaully swam across the river, ran across 295 until getting caught and is now at a Mental hospital for observation. I think that's a rabies type symptom too.

I agree, I think all people who perish from Alzheimer's and Parkinson's disease should should be tested. It makes sense. Who knows, maybe Prion infections are responsible.

mad cow disease

Submitted by Church Construction (not verified) on March 25, 2011 - 10:38am.

Many thanks for taking the time to discuss this,
Also, the military apparently knew about this for at least a few years now to because they did some testing on patients in a veterans hospital a few years back that were originally diagnosed as having alzheimer’s disease, because the symptoms are nearly identical to those of alzheimers. If I recall correctly, somewhere around 6% of the patients that they thought had died of alzheimers had actually died of the human form of mad cow disease instead.
The reason that this seems to be such an unknown is that there is no set policy for testing alzheimers patients for mad cow disease at the time of their death. For those that don't know, the only definitive test for mad cow is to take a tissue sample from the affected areas and it is quite an expensive procedure. Until the government starts some sort of policy for testing alzheimers patients for mad cow disease at the time of their death, we may never know exactly how prevalent this problem really is in this country. thanks for the sharing / Church Construction

USDA, SPONTANEOUS MAD COW DISEASE, THE TOOTH FAIRY AND SANTA

Submitted by flounder on June 14, 2006 - 11:32am.

hi john,

indeed, usda et al should have listened to you, sheldon, and everybody else
that have tried to tell them for eons about TSE in the USA. but instead,
USDA et al goes into cover-up mode, which is why this agent has now mutated
and spread to hell and back. in essence, the USA was worse than the UK about
spreading the agent via exports.
now, well, i think it is too late. lets compare ;

IN CONFIDENCE Perceptions of unconventional slow virus disease of animals in
the USA

G A H Wells

REPORT OF A VISIT TO THE USA APRIL-MAY 1989

john, check out pages 13 to 17

http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

Gerald Wells: Report of the Visit to USA, April-May 1989

snip...

The general opinion of those present was that BSE, as an
overt disease phenomenon, _could exist in the USA, but if it did,
it was very rare. The need for improved and specific surveillance
methods to detect it as recognised...

snip...

It is clear that USDA have little information and _no_ regulatory
responsibility for rendering plants in the US...

snip...

3. Prof. A. Robertson gave a brief account of BSE. The US approach
was to accord it a _very low profile indeed_. Dr. A Thiermann showed
the picture in the ''Independent'' with cattle being incinerated and thought
this was a fanatical incident to be _avoided_ in the US _at all costs_...

snip...

http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

To be published in the Proceedings of the
Fourth International Scientific Congress in
Fur Animal Production. Toronto, Canada,
August 21-28, 1988

Evidence That Transmissible Mink Encephalopathy
Results from Feeding Infected Cattle

R.F. Marsh* and G.R. Hartsough

.Department of Veterinary Science, University of Wisconsin-Madison, Madison,
Wisconsin 53706; and ^Emba/Creat Lakes Ranch Service, Thiensville, Wisconsin
53092

ABSTRACT

Epidemiologic investigation of a new incidence of
transmissible mink encephalopathy (TME) in Stetsonville, Wisconsin
suggests that the disease may have resulted from feeding infected
cattle to mink. This observation is supported by the transmission of
a TME-like disease to experimentally inoculated cattle, and by the
recent report of a new bovine spongiform encephalopathy in
England.

INTRODUCTION

Transmissible mink encephalopathy (TME) was first reported in 1965 by
Hartsough
and Burger who demonstrated that the disease was transmissible with a long
incubation
period, and that affected mink had a spongiform encephalopathy similar to
that found in
scrapie-affecied sheep (Hartsough and Burger, 1965; Burger and Hartsough,
1965).
Because of the similarity between TME and scrapie, and the subsequent
finding that the
two transmissible agents were indistinguishable (Marsh and Hanson, 1969), it
was
concluded that TME most likely resulted from feeding mink scrapie-infecied
sheep.
The experimental transmission of sheep scrapie to mink (Hanson et al., 1971)
confirmed the close association of TME and scrapie, but at the same time
provided
evidence that they may be different. Epidemiologic studies on previous
incidences of
TME indicated that the incubation periods in field cases were between six
months and
one year in length (Harxsough and Burger, 1965). Experimentally, scrapie
could not be
transmitted to mink in less than one year.

To investigate the possibility that TME may be caused by a (particular
strain of
scrapie which might be highly pathogenic for mink, 21 different strains of
the scrapie
agent, including their sheep or goat sources, were inoculated into a total
of 61 mink.
Only one mink developed a progressive neurologic disease after an incubation
period of
22 mon..s (Marsh and Hanson, 1979). These results indicated that TME was
either caused
by a strain of sheep scrapie not yet tested, or was due to exposure to a
scrapie-like agent
from an unidentified source.

OBSERVATIONS AND RESULTS

A New Incidence of TME. In April of 1985, a mink rancher in Stetsonville,
Wisconsin
reported that many of his mink were "acting funny", and some had died. At
this time, we
visited the farm and found that approximately 10% of all adult mink were
showing
typical signs of TME: insidious onset characterized by subtle behavioral
changes, loss of
normal habits of cleanliness, deposition of droppings throughout the pen
rather than in a
single area, hyperexcitability, difficulty in chewing and swallowing, and
tails arched over
their _backs like squirrels. These signs were followed by progressive
deterioration of
neurologic function beginning with locomoior incoordination, long periods of
somnolence
in which the affected mink would stand motionless with its head in the
corner of the
cage, complete debilitation, and death. Over the next 8-10 weeks,
approximately 40% of
all the adult mink on the farm died from TME.

Since previous incidences of TME were associated with common or shared
feeding
practices, we obtained a careful history of feed ingredients used over the
past 12-18
months. The rancher was a "dead stock" feeder using mostly (>95%) downer or
dead dairy
cattle and a few horses. Sheep had never been fed.

Experimental Transmission.

The clinical diagnosis of TME was confirmed by
histopaihologic examination and by experimental transmission to mink after
incubation
periods of four months. To investigate the possible involvement of cattle in
this disease
cycle, two six-week old castrated Holstein bull calves were inoculated
intracerebrally
with a brain suspension from affected mink. Each developed a fatal
spongiform
encephalopathy after incubation periods of 18 and 19 months.

DISCUSSION

These findings suggest that TME may result from feeding mink infected cattle
and
we have alerted bovine practitioners that there may exist an as yet
unrecognized
scrapie-like disease of cattle in the United States (Marsh and Hartsough,
1986). A new
bovine spongiform encephalopathy has recently been reported in England
(Wells et al.,
1987), and investigators are presently studying its transmissibility and
possible
relationship to scrapie. Because this new bovine disease in England is
characterized by
behavioral changes, hyperexcitability, and agressiveness, it is very likely
it would be
confused with rabies in the United Stales and not be diagnosed. Presently,
brains from
cattle in the United States which are suspected of rabies infection are only
tested with
anti-rabies virus antibody and are not examined histopathologically for
lesions of
spongiform encephalopathy.

We are presently pursuing additional studies to further examine the possible
involvement of cattle in the epidemiology of TME. One of these is the
backpassage of
our experimental bovine encephalopathy to mink. Because (here are as yet no
agent-
specific proteins or nucleic acids identified for these transmissible
neuropathogens, one
means of distinguishing them is by animal passage and selection of the
biotype which
grows best in a particular host. This procedure has been used to separate
hamster-
adapted and mink-udapted TME agents (Marsh and Hanson, 1979). The
intracerebral
backpassage of the experimental bovine agent resulted in incubations of only
four months
indicating no de-adaptation of the Stetsonville agent for mink after bovine
passage.
Mink fed infected bovine brain remain normal after six months. It will be
essential to
demonstrate oral transmission fiom bovine to mink it this proposed
epidemiologic
association is to be confirmed.

ACKNOWLEDGEMENTS

These studies were supported by the College of Agricultural and Life
Sciences,
University of Wisconsin-Madison and by a grant (85-CRCR-1-1812) from the
United
States Department of Agriculture. The authors also wish to acknowledge the
help and
encouragement of Robert Hanson who died during the course of these
investigations.

REFERENCES

Burger, D. and Hartsough, G.R. 1965. Encephalopathy of mink. II.
Experimental and
natural transmission. J. Infec. Dis. 115:393-399.
Hanson, R.P., Eckroade, R.3., Marsh, R.F., ZuRhein, C.M., Kanitz, C.L. and
Gustatson,
D.P. 1971. Susceptibility of mink to sheep scrapie. Science 172:859-861.
Hansough, G.R. and Burger, D. 1965. Encephalopathy of mink. I.
Epizoociologic and
clinical observations. 3. Infec. Dis. 115:387-392.
Marsh, R.F. and Hanson, R.P. 1969. Physical and chemical properties of
the
transmissible mink encephalopathy agent. 3. ViroL 3:176-180.
Marsh, R.F. and Hanson, R.P. 1979. On the origin of transmissible mink
encephalopathy. In Hadlow, W.J. and Prusiner, S.P. (eds.) Slow
transmissible
diseases of the nervous system. Vol. 1, Academic Press, New York, pp
451-460.
Marsh, R.F. and Hartsough, G.R. 1986. Is there a scrapie-like disease in
cattle?
Proceedings of the Seventh Annual Western Conference for Food Animal
Veterinary
Medicine. University of Arizona, pp 20.
Wells, G.A.H., Scott, A.C., Johnson, C.T., Cunning, R.F., Hancock, R.D.,
Jeffrey, M.,
Dawson, M. and Bradley, R. 1987. A novel progressive spongiform
encephalopathy
in cattle. Vet. Rec. 121:419-420.

MARSH

http://www.bseinquiry.gov.uk/files/mb/m09/tab05.pdf

WORLD ASSOCIATION FOR BUIATRICS
Edinburgh 8 -12 July 1996

http://www.bseinquiry.gov.uk/files/mb/m09/tab04.pdf

Transmission Studies of BSE in Sheep

http://www.bseinquiry.gov.uk/files/mb/m09/tab01.pdf

J. Comp. Path. 2006, Vol. 134, 63-69
Experimental Second Passage of Chronic Wasting
Disease (CWDmule deer) Agent to Cattle
A. N. Hamir, R. A. Kunkle, J. M. Miller, J. J. Greenlee and J. A. Richt
Agricultural Research Service, United States Department of Agriculture,
National Animal Disease Center, 2300 Dayton
Avenue, P.O. Box 70, Ames, IA 50010, USA
Summary
To compare clinicopathological findings in first and second passage chronic
wasting disease (CWDmule deer)
in cattle, six calves were inoculated intracerebrally with brain tissue
derived froma first-passageCWD-affected
calf in an earlier experiment. Two uninoculated calves served as controls.
The inoculated animals began to
lose both appetite and weight 10-12 months later, and five subsequently
developed clinical signs of central
nervous system (CNS) abnormality. By 16.5 months, all cattle had been
subjected to euthanasia because of
poor prognosis. None of the animals showed microscopical lesions of
spongiform encephalopathy (SE) but
PrPres was detected in their CNS tissues by immunohistochemistry (IHC) and
rapid Western blot (WB)
techniques. Thus, intracerebrally inoculated cattle not only amplified CWD
PrPres from mule deer but also
developed clinicalCNSsigns in the absence of SElesions.This situation has
also been shown to occur in cattle
inoculated with the scrapie agent. The study confirmed that the diagnostic
techniques currently used for
diagnosis of bovine spongiformencephalopathy (BSE) in theUS would detect
CWDin cattle, should it occur
naturally. Furthermore, it raised the possibility of distinguishing
CWDfromBSE in cattle, due to the absence
of neuropathological lesions and to a distinctive multifocal distribution of
PrPres, as demonstrated by IHC
which, in this study, appeared to be more sensitive than the WB technique.

snip...

Discussion

CWD, like all other TSEs, is characterized by a long
incubation period, which in deer is seldom less
than 18 months (Williams and Young, 1992). In an
experimental study of cattle inoculated intracerebrally
with CWD from mule deer (first passage),
amplification of PrPres was demonstrated in only
five of 13 (38%) cattle, after incubation periods
that ranged from 23 to 63 months (Hamir et al.,
2001a, 2005a). In contrast, all inoculated cattle in
the present study were positive for PrPres within
16.5 months. This increased attack rate with shorter
incubation periods probably indicates adaptation
of the CWDmule deer agent to a new host. It could
also be argued that the inoculum used for the
primary passage (Hamir et al., 2001a, 2005a) had a
lower infectivity titre than that used for the second
passage. However, the former successfully transmitted
CWD to each of five white tailed deer within
two years of intracerebral inoculation (Kunkle et al.,
Unpublished).
In cervids, clinical CWD is characterized by
emaciation, changes in behaviour, and excessive
salivation (Williams and Young, 1992). Although
the latter was not observed in the CWD inoculated
cattle, all animals showed anorexia and considerable
weight loss. Five cattle also showed intermittent
neurological signs. Although none of these
animals showed histopathological changes in the
brain, all were shown to be positive for PrPres by the
IHC and WB methods. The presence of isolated
vacuoles in the red nucleus is regarded as an
incidental finding in cattle (McGill and Wells,
1993).
The uniform susceptibility, relatively short incubation,
and absence of microscopical lesions in
cattle given CWD brain material passaged once
through cattle resembled findings in cattle inoculated
intracerebrally with the scrapie agent (Cutlip
et al., 1997). In that experiment, 100% of cattle
died 14-18 months after inoculation with material
from the first cattle-passage of a US strain of the
scrapie agent; none showed microscopical lesions
and all were positive for PrPres.
In the present experiment, the possibility that
the PrPres seen in tissue sections represented
residual CWD material from the inoculum was
ruled out because of the multifocal distribution of

PrPres throughout the brain (excluding cerebellar
folia) and cervical spinal cord of most of the
affected animals. Had the PrPres represented
residual inoculum, it would probably have been
confined to the sites of deposition in the midbrain
or cerebrum. Moreover, in studies on sheep
scrapie, Hamir et al. (2002) showed that intracerebrally
inoculated brain material containing PrPres
was present for only a few days in sufficient quantity
to be detectable immunohistochemically.
The present work confirms previous observations
that PrPres IHC labelling in cattle inoculated
with the mule deer CWD agent is multifocal
and glial cell-associated. This unusual pattern was
first reported in descriptions of the primary CWD
transmission to cattle (Hamir et al., 2001a, 2005a),
and the study described here showed that it was
maintained through the second passage in cattle.
Further studies now in progress will determine
whether this feature also characterizes CWD transmission
to cattle fromother cervid species other than
mule deer, namely, white tailed deer and elk.
In this and an earlier study of CWD in cattle
(Hamir et al., 2001a), IHC labelling differed from
that seen in cattle with BSE or experimental
transmissible mink encephalopathy (TME), both
of which are associated with widespread diffuse
labelling of grey matter neuropil, with labelled
particles that are not obviously cell-associated
except occasionally at neuronal cell membranes
(Wells and Willsmith, 1995; Hamir et al., 2005a).
The IHC pattern in bovine CWD also contrasts
markedly with that seen in scrapie-inoculated
cattle, in which intracytoplasmic labelling of
neurons is a prominent feature (Cutlip et al.,
1994, 1997).
When brainstems of CWD-infected cattle were
analysed by WB for the presence of PrPres, only
three of six samples were found to be positive
(Table 1). In contrast, all samples from the
midbrain area were positive by this technique
(Table 1; Fig. 5). It was noteworthy, however, that
both brainstem and midbrain sections of all
animals infected with CWD gave positive IHC
results (Table 1) and a positive WB was associated
with strong IHC labelling. This may indicate that
the IHC procedure is more sensitive than the WB
method for cattle-passaged CWD. However, given
the multifocal nature of PrPres distribution in the
CNS of CWD-infected cattle, this result is not
surprising. WB analysis requires a small sample of
brain tissue (e.g. 0.2 g, as in the present study) to
produce a 10% homogenate; approximately 10 ml
(1 mg brain tissue equivalent) of this homogenate
are loaded on to an SDS-PAGE gel for further

analysis. Bearing in mind the multifocal pattern of
PrPres distribution, the brain tissue used for the
preparation of WB homogenate, unlike the large
amount examined in the IHC procedure, might
well contain few if any foci of PrPres deposition,
whereas the larger piece of tissue section used for
IHC may contain detectable PrPres. In this respect,
therefore, the IHC method would seem preferable
to the WB procedure and to other procedures (e.g.
ELISA-based tests) in which only small amounts of
tissue are used for analysis.
In comparison with experimental TME in cattle
(Hamir et al., 2005b), the experimental bovine
CWD in this study was associated with less extensive
IHC labelling in non-CNS (i.e. other than brain
and spinal cord) neural tissues. Whereas the retina
was positive in all cattle inoculated with TME, none
of the CWD-infected cattle in this experiment had
any retinal labelling. Similarly, in the present study
there was no labelling in the pituitary gland, a
tissue sometimes positive in TME-infected cattle.
Because the incubation time for second passage
CWD transmission (mean of 468 days) was only
slightly longer than for TME (mean of 430 days), it
seems likely that these different tissue affinities
reflect a biological difference between these two
TSE agents.
PrPres IHC labelling was not observed in striated
muscles (heart, tongue, masseter, diaphragm) of
the experimental animals. This observation
accorded with our previous findings (Hamir et al.,
2004a) in which striated muscle tissues from 20
animals (cattle, sheep, elk and raccoons) were
examined for PrPres. In these animals, all of which
had developed a TSE after experimental inoculation,
PrPres was found by IHC examination in the
brains, but not in muscle tissues. However, recent
investigations with an enriched WB technique
(Mulcahy et al., 2004) have enabled us to detect
PrPres in the tongues of some sheep and elk
experimentally inoculated with scrapie and CWD,
respectively. This technique failed, however, to
detect PrPres in cattle inoculated with CWD or
TME (Bessen et al., unpublished). This study is still
in progress, and the tongues of TSE-infected
animals are currently being tested after careful
removal from the carcasses to ensure non-contamination
with infected brain material.
The present study and a previous experiment
(Hamir et al., 2005a) have established the biological
characteristics of the CWDmule deer agent in cattle.
However, isolates of CWD from other cervids (e.g.
CWDwhite-tailed and CWDelk) may differ. Transmission
experiments with different CWD isolates
are therefore needed to examine the possibility of
variation in the CWD agent in wild cervids. Such
experiments have recently been initiated at the
National Animal Disease Center (NADC).............snip...END...TSS

ALSO, I THINK THE DOWNER COW FIGURE IS UNDERESTIMATED;

Released May 5, 2005, by the National Agricultural Statistics Service
(NASS), Agricultural Statistics Board, U.S. Department
of Agriculture. For information on Non-ambulatory Cattle and Calves call
Mike Miller at 720-3040, office hours 7:30 a.m. to
4:30 p.m. ET.
Non-Ambulatory Cattle and Calves
Non-ambulatory cattle and calves in the United States totaled 465,000 head
during 2003 and
450,000 head during 2004. The number of non-ambulatory cattle 500 pounds or
greater totaled
280,000 head in 2003 and 270,000 head in 2004. The number of calves under
500 pounds reported
as non-ambulatory totaled 185,000 head in 2003 and 180,000 head in 2004.
The number of operations that reported non-ambulatory cattle and calves was
103,000 in 2003 and
81,000 in 2004. In 2003, there were 66,800 beef cow operations reporting
non-ambulatory cattle
and calves compared to 49,700 in 2004. There were 22,800 dairy operations
reporting nonambulatory
cattle and calves in 2003 compared to 23,000 in 2004.
This report is released as a cooperative effort between the National
Agricultural Statistics Service
and Animal and Plant Health Inspection Service - Veterinary Services. Data
for this report were
collected on the January 1, 2004 and 2005 Cattle Surveys. .......END....TSS

From: TSS ()
Subject: Interspecies Transmission of Chronic Wasting Disease Prions to
Squirrel Monkeys (Saimiri sciureus)
Date: October 19, 2005 at 8:33 am PST

0022-538X/05/$08.00+0 doi:10.1128/JVI.79.21.13794-13796.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Interspecies Transmission of Chronic Wasting Disease Prions to Squirrel
Monkeys (Saimiri sciureus)
Richard F. Marsh,1, Anthony E. Kincaid,2 Richard A. Bessen,3 and Jason C.
Bartz4*
Department of Animal Health and Biomedical Sciences, University of
Wisconsin, Madison 53706,1 Department of Physical Therapy,2 Department of
Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
68178,4 Department of Veterinary Molecular Biology, Montana State
University, Bozeman, Montana 597183

Received 3 May 2005/ Accepted 10 August 2005

Chronic wasting disease (CWD) is an emerging prion disease of deer and elk.
The risk of CWD transmission to humans following exposure to CWD-infected
tissues is unknown. To assess the susceptibility of nonhuman primates to
CWD, two squirrel monkeys were inoculated with brain tissue from a
CWD-infected mule deer. The CWD-inoculated squirrel monkeys developed a
progressive neurodegenerative disease and were euthanized at 31 and 34
months postinfection. Brain tissue from the CWD-infected squirrel monkeys
contained the abnormal isoform of the prion protein, PrP-res, and displayed
spongiform degeneration. This is the first reported transmission of CWD to
primates.

----------------------------------------------------------------------------
----

* Corresponding author. Mailing address: Department of Medical Microbiology
and Immunology, Creighton University, 2500 California Plaza, Omaha, NE
68178. Phone: (402) 280-1811. Fax: (402) 280-1875. E-mail:
jbartz@creighton.edu .

Deceased.

----------------------------------------------------------------------------
----

Journal of Virology, November 2005, p. 13794-13796, Vol. 79, No. 21
0022-538X/05/$08.00+0 doi:10.1128/JVI.79.21.13794-13796.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

http://jvi.asm.org/cgi/content/abstract/79/21/13794?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=cwd&searchid=1129736446553_4280&stored_search=&FIRSTINDEX=0&volume=79&issue=21&journalcode=jvi

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

Intra- & Inter-species Transmission of Chronic Wasting Disease (Show All
REXs)
Description: This research is intended to investigate the intra- and
inter-species transmissibility of the causative agent of chronic wasting
disease (CWD), believed to be a structurally modified form of the prion
protein (PrPCWD), of white-tailed deer (Odocoileus virginianus). Our lab has
identified five alleles in the PrP-coding region of white-tailed deer from
the CWD-affected region of southern Wisconsin. Combinations of the alleles
represent variability within the population and may result in differences in
incubation period, levels of susceptibility, variable clinical symptoms
and/or pathology within deer. We will test these ideas by inoculating
white-tailed deer of known genotype with known-genotype PrPCWD and by
conducting cell-free conversion experiments with the possible combinations
of PrPCWD. We believe environment may be a reservoir of CWD, which opens
possibilities of transmission to wildlife that share habitat with
white-tailed deer. We will identify the species that consume deer carrion,
as they are the most likely to encounter PrPCWD, collect 100 of each species
from the CWD-affected region of southern Wisconsin and evaluate them for
lesion profiles indicative of prion disease. We believe the primary carrion
consumers will include coyote (Canis latrans), red fox (Vulpes vulpes), gray
fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), striped skunk
(Mephitis mephitis), Virginia opossum (Didelphis virginiana), and mink
(Mustela vison). Since species barriers are difficult to cross we dont
expect to find a large prevalence of prion disease in this population of
wildlife. To address the possibility of transmission to these species, we
will inoculate raccoons, striped skunks, Virginia opossums and Eastern
cottontails (Sylvilagus floridanus) with PrPCWD. We will test transmission
to other species by cell-free conversion with as many species as possible,
starting with those whose life history are most likely to expose them to
PrPCWD. The species that we are collecting from the CWD-affected region of
southern Wisconsin for prion disease assessment are a significant collection
that we will use to survey a range of other wildlife diseases. This is a
five-year project with publications anticipated in the third through fifth
year. Students that would join me for work could experience lab or field
work. We will be placing dead deer on the landscape, setting
remote-triggered cameras on the deer and checking the cameras every other
day. We will collect raccoons, skunks, opossums, coyotes and foxes from
trappers and conduct necropsies on them at the WVDL. We will be running
Western blots for TSE testing on the brains of the animals we necropsy. We
will do PCR/Sequencing on the prion-coding region of each species, clone it
into an expression vector and conduct cell-free conversions on the resulting
protein.

Date: Feb 20
Week: Week 1 (Week of Feb 20)
Location (where students meet host): Room 237 Animal Health & Biomedical
Sciences Building, 1656 Linden Drive
Meets From: 3:30 pm until 5:30 pm
Pre-REX Reading: None

Laboratory:
Lab Address: 237 Animal Health & Biomedical Sciences Bldg, 1656 Linden Drive
Lab Phone: 262-7362
Lab Website: http://www.ahabs.wisc.edu/Faculty/Aiken-j/index.html

Department or Institute: Animal Health & Biomedical Sciences
College or School: School of Veterinary Medicine

Host: Dr. Judd Aiken
Host Email: jma@ahabs.wisc.edu
Host Phone: 262-7362
Co-Host: Chad Johnson
Co-Host Email: cjjohns3@students.wisc.edu
Co-Host Phone:

Total Number of Students Allowed: 5
Number of Openings: 0

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

USA EXPORTS

2006

http://www.ers.usda.gov/Briefing/Cattle/Data/AnnualLivestockTable.xls

TOP FIVE COUNTRIES IMPORTING USDA MAD COW PRODUCTS

The Economic Impact of BSE
on the U.S. Beef Industry:
Product Value Losses, Regulatory
Costs, and Consumer Reactions

3.4 U.S. Beef Export Customers
Table 3.4 provides a dollar value ranking,
by country, of beef export shipments during
2003. Five countries, Japan, Mexico, South
Korea, Canada, and Hong Kong, were the
recipients of 90 percent of U.S .beef exports
during 2003, based on value. Japan, historically
the largest U.S. beef export customer,
represented 35 percent of U.S. beef exports
during 2003.

http://www.ksda.gov/Default.aspx?tabid=349&mid=2252&ctl=Download&method=attachment&EntryId=479

WHOS EATING THOSE USDA MAD COW BRAINS OF AN ATYPICAL STRAIN ?

0206.29.0010: HEARTS OF BOVINE ANIMALS, EDIBLE, FROZEN

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