Tuesday, February 22, 2011

Chronic wasting disease spreads farther west in Alberta

Chronic wasting disease spreads farther west in Alberta

Within five years could be found at Edmonton’s outskirts and in Calgary

By Hanneke Brooymans,

Chronic wasting disease in deer has spread farther west into the province and within five years will likely be found at Edmonton’s outskirts and in Calgary, says a University of Alberta biologist.

Dave Coltman came to that conclusion after looking at the latest testing results and map posted by Alberta Sustainable Resource Development last week.

Altogether, 17 new cases were found in the nearly 4,200 deer tested since September 2010. That brings the total number of wild deer cases found in Alberta since 2005 to 91.

CWD is caused by a prion, similar to bovine spongiform encephalopathy, that causes deer to slowly waste away.

In the past two years, the government has relied on a hunter surveillance program to track the spread of the disease.

Government staff collect the heads of deer killed by hunters in specific wildlife management areas where past cases have been found. They also test deer hunted in areas close to past cases. Prior to that, they had also used an aggressive winter cull program to reduce the densities of deer in infected areas.

Coltman, a biology professor who studies CWD, said the most recent map of the cases shows there are four new ones in a new wildlife management unit. He said the disease, as expected, is moving along river valleys.

“Those are like superhighways for CWD and deer.”

There are likely many more cases that haven’t been found, he said.

“If we’re going to continue to have surveillance to guess where the leading edge of this thing is, we’re going to have to go another set of management units further west, particularly in the south. It’s at the gates of Calgary now, basically.”

Alberta Sustainable Resource Development spokesman Darcy Whiteside said the testing program is nearing completion for the season. When it wraps up, they will evaluate their disease management program to see how it might change next season.

There is no evidence that the disease in its current form can infect humans. But research published earlier this year out of the United States suggests that over time, as the strain adapts over successive generations in the wild, it could become progressively more transmissible to humans. The study, published in The Journal of Biological Chemistry, said the transformation could take years or decades, or might not even happen. But it also notes that it is likely that CWD prions are progressively accumulating in the environment, since they bind tightly to soil and can remain infectious for a long time.

Coltman said there’s a delicate line to walk when talking about the risks associated with the disease. He doesn’t want to sound alarmist, but he also said that everyone working in the field expects there will come a day when a new form of a prion disease evolves from CWD and it could become transmissible to humans. The public wants to know what the chance is that that will happen. “It’s a very small number. ... But the day that it does happen it will blow up. And people will say, ‘Holy cow, we let it go and now look where we are.’ ”

Some hunters, when they get a call telling them their animal was positive, say they’ve already eaten the animal and don’t care.

“We tell people you can store it in the freezer until you get the results, but the (U.S. Centers for Disease Control) has found no link between eating deer or elk and prion disease in humans,” Whiteside said.

The World Health Organization recommends a precautionary approach, though, and says any animal product known to be infected with any prion disease should not be consumed by humans.

“Personally, I’d think twice about eating a deer if I knew it was positive,” Coltman said.


Read more:



Thursday, February 10, 2011

TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY REPORT UPDATE CANADA FEBRUARY 2011 and how to hide mad cow disease in Canada Current as of: 2011-01-31


Is Chronic Wasting Disease transmissible to man ?

I believe that the assumption that Chronic Wasting Disease is not infectious to man, is just that, an assumption, one that should be proven, not assumed. In my research of scientific studies on this matter, I have found that there is more science to show that indeed Chronic Wasting Disease is transmissible to man, than there is showing that it is not. The only problem is, scientist and the media refuse to acknowledge the science, and continue to go by a myth, and assume that it is not. This assumption could prove fatal in the long run. for how many, that is another assumption, but one that should be considered. ...

A kind greetings from Bacliff, Texas !

please use this information with how ever many grains of salt you wish, i don't care what you eat.

cutting out the high risk cns portions will not do away with all the risk, even if you don't cut yourselves by butcher. they have now found in CWD the prion TSE agent in muscle and fat tissue, now they say with smaller amounts of infectivity, but i personally believe in the accumaltion as a factor of risk as well. seems these prion strains as they mutate, the get more virulent. you accumulate enough of the prions and you become clinical. what the threshold from sub-clinical to clinical would be, would depend on the route, the source, titre of infectivity, and ones genetic make up, and whom you expose and or infect while being sub-clinically exposed via the medical and surgical arena's i.e. friendly fire, is a frightening thought now, and a real risk factor. for them to keep saying that there is no _known_ risk factor to humans, with the cjd surveillance system and diagnostic criteria, they would never know. you are correct about the officials being misinformed and misleading. that's why i post the science behind any reports they publish on CWD, hoping someone will read it. personally i think the deer and elk hunting industry were a pawn in a big game of chess. the king was the cattle industry. they have brain washed every one into believing scrapie will not transmit to man, when all science shows that it will. the deer and elk industry were sacrificed. USDA et al tried to cover up mad cow disease, because the evidence was already out (without using a human guinea pig, which i promote over primates i.e. death row inmates, that's another story though), so they just kept saying cwd would not transmit to humans. when the evidence was the same for BSE to humans as it was for CWD to humans, as with Scrapie, and they knew this in 2000, or earlier. the evidence was the same in that study i.e. raymand et al, no matter how low, or high the risk factor is, the risk was the same for BSE, Scrapie, and CWD to humans ;

Clearly, it is premature to draw firm conclusions about CWD passing naturally into humans, cattle and sheep, but the present results suggest that CWD transmissions to humans would be as limited by PrP incompatibility as transmissions of BSE or sheep scrapie to humans. Although there is no evidence that sheep scrapie has affected humans, it is likely that BSE has caused variant CJD in 74 people (definite and probable variant CJD cases to date according to the UK CJD Surveillance Unit). Given the presumably large number of people exposed to BSE infectivity, the susceptibility of humans may still be very low compared with cattle, which would be consistent with the relatively inefficient conversion of human PrP-sen by PrPBSE. Nonetheless, since humans have apparently been infected by BSE, it would seem prudent to take reasonable measures to limit exposure of humans (as well as sheep and cattle) to CWD infectivity as has been recommended for other animal TSEs.


THEN, 11 years later you get this ;


Our findings demonstrate that cervid PrPSc, upon strain adaptation by serial passages in vitro or in cervid transgenic mice, is capable of converting human PrPC to produce PrPSc with unique biochemical properties, likely representing a new human prion strain. The newly generated CWD-huPrPSc material has been inoculated into transgenic mice expressing human PrP to study infectivity and disease phenotype and this data will be published elsewhere. ...end


then you had this data ;


October 1994

Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge Spencers Lane BerksWell Coventry CV7 7BZ

Dear Mr Elmhirst,


Thank you for your recent letter concerning the publication of the third annual report from the CJD Surveillance Unit. I am sorry that you are dissatisfied with the way in which this report was published.

The Surveillance Unit is a completely independant outside body and the Department of Health is committed to publishing their reports as soon as they become available. In the circumstances it is not the practice to circulate the report for comment since the findings of the report would not be amended. In future we can ensure that the British Deer Farmers Association receives a copy of the report in advance of publication.

The Chief Medical Officer has undertaken to keep the public fully informed of the results of any research in respect of CJD. This report was entirely the work of the unit and was produced completely independantly of the the Department.

The statistical results reqarding the consumption of venison was put into perspective in the body of the report and was not mentioned at all in the press release. Media attention regarding this report was low key but gave a realistic presentation of the statistical findings of the Unit. This approach to publication was successful in that consumption of venison was highlighted only once by the media ie. in the News at one television proqramme.

I believe that a further statement about the report, or indeed statistical links between CJD and consumption of venison, would increase, and quite possibly give damaging credence, to the whole issue. From the low key media reports of which I am aware it seems unlikely that venison consumption will suffer adversely, if at all.


and why do we not want to do TSE transmission studies on chimpanzees $


5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.




Prions in Skeletal Muscles of Deer with Chronic Wasting Disease

Rachel C. Angers1,*, Shawn R. Browning1,*?, Tanya S. Seward2, Christina J. Sigurdson4,?, Michael W. Miller5, Edward A. Hoover4 and Glenn C. Telling1,2,3,§ + Author Affiliations


The emergence of chronic wasting disease (CWD) in deer and elk in an increasingly wide geographic area, as well as the interspecies transmission of bovine spongiform encephalopathy to humans in the form of variant Creutzfeldt Jakob disease, have raised concerns about the zoonotic potential of CWD. Because meat consumption is the most likely means of exposure, it is important to determine whether skeletal muscle of diseased cervids contains prion infectivity. Here bioassays in transgenic mice expressing cervid prion protein revealed the presence of infectious prions in skeletal muscles of CWD-infected deer, demonstrating that humans consuming or handling meat from CWD-infected deer are at risk to prion exposure.

Received for publication 21 November 2005. Accepted for publication 13 January 2006.


Journal of Virology, September 2009, p. 9608-9610, Vol. 83, No. 18 0022-538X/09/$08.00+0 doi:10.1128/JVI.01127-09 Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Prion Infectivity in Fat of Deer with Chronic Wasting Disease

Brent Race,# Kimberly Meade-White,# Richard Race, and Bruce Chesebro* Rocky Mountain Laboratories, 903 South 4th Street, Hamilton, Montana 59840

Received 2 June 2009/ Accepted 24 June 2009


Chronic wasting disease (CWD) is a neurodegenerative prion disease of cervids. Some animal prion diseases, such as bovine spongiform encephalopathy, can infect humans; however, human susceptibility to CWD is unknown. In ruminants, prion infectivity is found in central nervous system and lymphoid tissues, with smaller amounts in intestine and muscle. In mice, prion infectivity was recently detected in fat. Since ruminant fat is consumed by humans and fed to animals, we determined infectivity titers in fat from two CWD-infected deer. Deer fat devoid of muscle contained low levels of CWD infectivity and might be a risk factor for prion infection of other species.


The highest risk of human contact with CWD might be through exposure to high-titer CNS tissue through accidental skin cuts or corneal contact at the time of harvest and butchering. However, the likelihood of a human consuming fat infected with a low titer of the CWD agent is much higher. It is impossible to remove all the fat present within muscle tissue, and fat consumption is inevitable when eating meat. Of additional concern is the fact that meat from an individual deer harvested by a hunter is typically consumed over multiple meals by the same group of people. These individuals would thus have multiple exposures to the CWD agent over time, which might increase the chance for transfer of infection.

In the Rocky Mountain region of North America, wild deer are subject to predation by wolves, coyotes, bears, and mountain lions. Although canines such as wolves and coyotes are not known to be susceptible to prion diseases, felines definitely are susceptible to BSE (9) and might also be infected by the CWD agent. Deer infected with the CWD agent are more likely to be killed by predators such as mountain lions (11). Peripheral tissues, including lymph nodes, muscle, and fat, which harbor prion infectivity are more accessible for consumption than CNS tissue, which has the highest level of infectivity late in disease. Therefore, infectivity in these peripheral tissues may be important in potential cross-species CWD transmissions in the wild.

The present finding of CWD infectivity in deer fat tissue raises the possibility that prion infectivity might also be found in fat tissue of other infected ruminants, such as sheep and cattle, whose fat and muscle tissues are more widely distributed in both the human and domestic-animal food chains. Although the infectivity in fat tissues is low compared to that in the CNS, there may be significant differences among species and between prion strains. Two fat samples from BSE agent-infected cattle were reported to be negative by bioassay in nontransgenic RIII mice (3, 6). However, RIII mice are 10,000-fold-less sensitive to BSE agent infection than transgenic mice expressing bovine PrP (4). It would be prudent to carry out additional infectivity assays on fat from BSE agent-infected cattle and scrapie agent-infected sheep using appropriate transgenic mice or homologous species to determine the risk from these sources.



WHO Tables on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies Updated 2010


The assignment of tissues to high, low, and undetected infectivity categories is based exclusively upon observations of naturally occurring disease, or primary experimental infection by the oral route (in ruminants). The Tables do not include results from disease models using strains of TSE that have been adapted to experimental animals, because passaged strain phenotypes can differ significantly and unpredictably from those of naturally occurring disease. However, for tissues and fluids of exceptional public health interest, such as muscle, intestine, skin, secretions and excretions, experimental results have been indicated in footnotes.

Because the detection of misfolded prion protein (PrPTSE) broadly parallels infectivity titers in various tissues [Beekes et al 1996; Andreoletti et al 2004], PrPTSE testing results are presented in parallel with bioassay data.

Although a given tissue may be positive or negative in different varieties of TSE, the expert group considered a tissue to be potentially infectious even if a positive result occurred in only a single disease. The categorical assignment of tissues will almost certainly undergo further revision as new data accumulate from increasingly sensitive tests.

IA: High-infectivity tissues: CNS tissues that attain a high titer of infectivity in the later stages of all TSEs, and certain tissues that are anatomically associated with the CNS.

IB: Lower-infectivity tissues: peripheral tissues that have tested positive for infectivity and/or PrPTSE in at least one form of TSE.

IC: Tissues with no detectable infectivity: tissues that have been examined for infectivity and/or PrPTSE with negative results.

Data entries are shown as follows:

+ Presence of infectivity or PrPTSE

- Absence of detectable infectivity or PrPTSE

NT Not tested

NA Not applicable ?

Uncertain interpretation

( ) Limited or preliminary data

[ ] Infectivity or PrPTSE data based exclusively on bioassays in transgenic

(Tg)mice over-expressing the PrP-encoding gene or PrPTSE amplification methods.

A word of caution is offered about tissues in Table IB for which positive results are so far limited to either detection of PrPTSE using amplification techniques (PMCA), or infectivity bioassays in Tg mice that over-express PrP. The amounts of pathological protein or infectious agent detected by these exquisitely sensitive assays may well fall below the threshold of transmissibility for normal animals and humans. WHO Tables on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies 5

A good example is illustrated in the studies of urine and feces from deer infected with CWD: bioassays using normal deer as recipient subjects were negative; subsequent bioassays performed in Tg mice were positive. A similar discordance was observed for BSE muscle inoculated into cattle and Tgmice. Until more evidence is compiled showing that positive results in experimental PMCA and Tg mouse assays equate to a risk of transmitting disease under natural conditions, it cannot be assumed that such results imply the existence of a substantial risk to the health of animals or humans.

Considering the succession of updated Tables of the past few years, and the fact that inflammation has been shown to result in PrPTSE deposition in tissues that are not normally involved in TSE pathogenesis, it is evident that as testing continues, more tissues will find their way from Table IC into Table IB (but probably not from either Table IC or IB into Table IA). It is also evident that the data generated to date are far from complete, and that a great deal more work needs to be done if conclusions about the tissue distribution and significance of infectivity in a given TSE are to be based on direct measurements rather than by analogy to other forms of the disease.

Finally, it is critically important to understand that categories of infectivity are not the same as categories of risk, which require consideration not only of the level of infectivity in tissue, but also of the amount of tissue to which a person or animal is exposed, and the route by which infection is transmitted. For example, although the level of tissue infectivity is the most important factor in estimating the risk of transmission by instrument crosscontamination during surgical procedures (e.g., neurosurgery versus general surgery), it will be only one determinant of the risk of transmission by blood transfusions, in which a large amount of low-infectivity blood is administered intravenously, or the risk of transmission by foodstuffs that, irrespective of high or low infectivity, involve a comparatively inefficient oral route of infection.


Table IC: Tissues with no detected infectivity or PrPTSE


Musculo-skeletal tissues

Bone NT - NT - - NT NT NT NT NT

Tendon NT - NT - - NT NT NT NT NT


please see full text with tables here ;

WHO Tables on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies Updated 2010

also in the references at bottom i saw ;

12. A single positive marrow in multiple transmission attempts from cattle orally dosed with BSE-infected brain [Wells et al., 1999; Wells et al., 2005; Sohn et al., 2009].



Wednesday, September 08, 2010


please see ;


there are now two documented strains of CWD, and science is showing that indeed CWD could transmit to humans via transmission studies ;



Chad Johnson1, Judd Aiken2,3,4 and Debbie McKenzie4,5 1 Department of Comparative Biosciences, University of Wisconsin, Madison WI, USA 53706 2 Department of Agriculture, Food and Nutritional Sciences, 3 Alberta Veterinary Research Institute, 4.Center for Prions and Protein Folding Diseases, 5 Department of Biological Sciences, University of Alberta, Edmonton AB, Canada T6G 2P5

The identification and characterization of prion strains is increasingly important for the diagnosis and biological definition of these infectious pathogens. Although well-established in scrapie and, more recently, in BSE, comparatively little is known about the possibility of prion strains in chronic wasting disease (CWD), a disease affecting free ranging and captive cervids, primarily in North America. We have identified prion protein variants in the white-tailed deer population and demonstrated that Prnp genotype affects the susceptibility/disease progression of white-tailed deer to CWD agent. The existence of cervid prion protein variants raises the likelihood of distinct CWD strains. Small rodent models are a useful means of identifying prion strains. We intracerebrally inoculated hamsters with brain homogenates and phosphotungstate concentrated preparations from CWD positive hunter-harvested (Wisconsin CWD endemic area) and experimentally infected deer of known Prnp genotypes. These transmission studies resulted in clinical presentation in primary passage of concentrated CWD prions. Subclinical infection was established with the other primary passages based on the detection of PrPCWD in the brains of hamsters and the successful disease transmission upon second passage. Second and third passage data, when compared to transmission studies using different CWD inocula (Raymond et al., 2007) indicate that the CWD agent present in the Wisconsin white-tailed deer population is different than the strain(s) present in elk, mule-deer and white-tailed deer from the western United States endemic region.



Prion Transmission from Cervids to Humans is Strain-dependent

Qingzhong Kong, Shenghai Huang,*Fusong Chen, Michael Payne, Pierluigi Gambetti and Liuting Qing Department of Pathology; Case western Reserve University; Cleveland, OH USA *Current address: Nursing Informatics; Memorial Sloan-Kettering Cancer Center; New York, NY USA

Key words: CWD, strain, human transmission

Chronic wasting disease (CWD) is a widespread prion disease in cervids (deer and elk) in North America where significant human exposure to CWD is likely and zoonotic transmission of CWD is a concern. Current evidence indicates a strong barrier for transmission of the classical CWD strain to humans with the PrP-129MM genotype. A few recent reports suggest the presence of two or more CWD strains. What remain unknown is whether individuals with the PrP-129VV/MV genotypes are also resistant to the classical CWD strain and whether humans are resistant to all natural or adapted cervid prion strains. Here we report that a human prion strain that had adopted the cervid prion protein (PrP) sequence through passage in cervidized transgenic mice efficiently infected transgenic mice expressing human PrP, indicating that the species barrier from cervid to humans is prion strain-dependent and humans can be vulnerable to novel cervid prion strains. Preliminary results on CWD transmission in transgenic mice expressing human PrP-129V will also be discussed.

Acknowledgement Supported by NINDS NS052319 and NIA AG14359.


Generation of a Novel form of Human PrPSc by Inter-species Transmission of Cervid Prions

Marcelo A. Barria,1 Glenn C. Telling,2 Pierluigi Gambetti,3 James A. Mastrianni4 and Claudio Soto1 1Mitchell Center for Alzheimer's disease and related Brain disorders; Dept of Neurology; University of Texas Houston Medical School; Houston, TX USA; 2Dept of Microbiology, Immunology & Molecular Genetics and Neurology; Sanders Brown Center on Aging; University of Kentucky Medical Center; Lexington, KY USA; 3Institute of Pathology; Case western Reserve University; Cleveland, OH USA; 4Dept of Neurology; University of Chicago; Chicago, IL USA

Prion diseases are infectious neurodegenerative disorders affecting humans and animals that result from the conversion of normal prion protein (PrPC) into the misfolded and infectious prion (PrPSc). Chronic wasting disease (CWD) of cervids is a prion disorder of increasing prevalence within the United States that affects a large population of wild and captive deer and elk. CWD is highly contagious and its origin, mechanism of transmission and exact prevalence are currently unclear. The risk of transmission of CWD to humans is unknown. Defining that risk is of utmost importance, considering that people have been infected by animal prions, resulting in new fatal diseases. To study the possibility that human PrPC can be converted into the infectious form by CWD PrPSc we performed experiments using the Protein Misfolding Cyclic Amplification (PMCA) technique, which mimic in vitro the process of prion replication. Our results show that cervid PrPSc can induce the pathological conversion of human PrPC, but only after the CWD prion strain has been stabilized by successive passages in vitro or in vivo. Interestingly, this newly generated human PrPSc exhibits a distinct biochemical pattern that differs from any of the currently known forms of human PrPSc, indicating that it corresponds to a novel human prion strain. Our findings suggest that CWD prions have the capability to infect humans, and that this ability depends on CWD strain adaptation, implying that the risk for human health progressively increases with the spread of CWD among cervids.


Biochemical and Biophysical Characterization of Different CWD Isolates

Martin L. Daus and Michael Beekes Robert Koch Institute; Berlin, Germany

Key words: CWD, strains, FT-IR, AFM

Chronic wasting disease (CWD) is one of three naturally occurring forms of prion disease. The other two are Creutzfeldt-Jakob disease in humans and scrapie in sheep. CWD is contagious and affects captive as well as free ranging cervids. As long as there is no definite answer of whether CWD can breach the species barrier to humans precautionary measures especially for the protection of consumers need to be considered. In principle, different strains of CWD may be associated with different risks of transmission to humans. Sophisticated strain differentiation as accomplished for other prion diseases has not yet been established for CWD. However, several different findings indicate that there exists more than one strain of CWD agent in cervids. We have analysed a set of CWD isolates from white-tailed deer and could detect at least two biochemically different forms of disease-associated prion protein PrPTSE. Limited proteolysis with different concentrations of proteinase K and/or after exposure of PrPTSE to different pH-values or concentrations of Guanidinium hydrochloride resulted in distinct isolate-specific digestion patterns. Our CWD isolates were also examined in protein misfolding cyclic amplification studies. This showed different conversion activities for those isolates that had displayed significantly different sensitivities to limited proteolysis by PK in the biochemical experiments described above. We further applied Fourier transform infrared spectroscopy in combination with atomic force microscopy. This confirmed structural differences in the PrPTSE of at least two disinct CWD isolates. The data presented here substantiate and expand previous reports on the existence of different CWD strains.




Wednesday, September 08, 2010



From: TSS (216-119-163-189.ipset45.wt.net)


Date: September 30, 2002 at 7:06 am PST

From: "Belay, Ermias"


Cc: "Race, Richard (NIH)" ; ; "Belay, Ermias"

Sent: Monday, September 30, 2002 9:22 AM


Dear Sir/Madam, In the Archives of Neurology you quoted (the abstract of which was attached to your email), we did not say CWD in humans will present like variant CJD.

That assumption would be wrong. I encourage you to read the whole article and call me if you have questions or need more clarification (phone: 404-639-3091). Also, we do not claim that "no-one has ever been infected with prion disease from eating venison." Our conclusion stating that we found no strong evidence of CWD transmission to humans in the article you quoted or in any other forum is limited to the patients we investigated.

Ermias Belay, M.D. Centers for Disease Control and Prevention

-----Original Message-----


Sent: Sunday, September 29, 2002 10:15 AM

To: [log in to unmask]">[log in to unmask]; [log in to unmask]">[log in to unmask]; [log in to unmask]">[log in to unmask]


Sunday, November 10, 2002 6:26 PM ......snip........end..............TSS


full text ;


FDA is not recalling this CWD positive elk meat for the well being of the dead elk ;

Wednesday, March 18, 2009

Noah's Ark Holding, LLC, Dawson, MN RECALL Elk products contain meat derived from an elk confirmed to have CWD NV, CA, TX, CO, NY, UT, FL, OK RECALLS AND FIELD CORRECTIONS: FOODS CLASS II


see full text ;



New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication

Paul Brown*,dagger , Edward H. RauDagger , Bruce K. Johnson*, Alfred E. Bacote*, Clarence J. Gibbs Jr.*, and D. Carleton Gajdusek§

* Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, and Dagger Environmental Protection Branch, Division of Safety, Office of Research Services, National Institutes of Health, Bethesda, MD 20892; and § Institut Alfred Fessard, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France

Contributed by D. Carleton Gajdusek, December 22, 1999


One-gram samples from a pool of crude brain tissue from hamsters infected with the 263K strain of hamster-adapted scrapie agent were placed in covered quartz-glass crucibles and exposed for either 5 or 15 min to dry heat at temperatures ranging from 150°C to 1,000°C. Residual infectivity in the treated samples was assayed by the intracerebral inoculation of dilution series into healthy weanling hamsters, which were observed for 10 months; disease transmissions were verified by Western blot testing for proteinase-resistant protein in brains from clinically positive hamsters. Unheated control tissue contained 9.9 log10LD50/g tissue; after exposure to 150°C, titers equaled or exceeded 6 log10LD50/g, and after exposure to 300°C, titers equaled or exceeded 4 log10LD50/g. Exposure to 600°C completely ashed the brain samples, which, when reconstituted with saline to their original weights, transmitted disease to 5 of 35 inoculated hamsters. No transmissions occurred after exposure to 1,000°C. These results suggest that an inorganic molecular template with a decomposition point near 600°C is capable of nucleating the biological replication of the scrapie agent.

transmissible spongiform encephalopathy | scrapie | prion | medical waste | incineration


The infectious agents responsible for transmissible spongiform encephalopathy (TSE) are notoriously resistant to most physical and chemical methods used for inactivating pathogens, including heat. It has long been recognized, for example, that boiling is ineffective and that higher temperatures are most efficient when combined with steam under pressure (i.e., autoclaving). As a means of decontamination, dry heat is used only at the extremely high temperatures achieved during incineration, usually in excess of 600°C. It has been assumed, without proof, that incineration totally inactivates the agents of TSE, whether of human or animal origin. It also has been assumed that the replication of these agents is a strictly biological process (1), although the notion of a "virus" nucleant of an inorganic molecular cast of the infectious beta -pleated peptide also has been advanced (2). In this paper, we address these issues by means of dry heat inactivation studies.

see full text:


Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production

Cathrin E. Bruederle1*, Robert M. Hnasko1, Thomas Kraemer2, Rafael A. Garcia3, Michael J. Haas3, William N. Marmer3, John Mark Carter1

1 USDA-ARS WRRC, Foodborne Contaminants Research Unit, Albany, California, United States of America, 2 Forensic Toxicology, Institute of Legal Medicine, Saarland University, Homburg/Saar, Germany, 3 USDA-ARS ERRC, Fats, Oils and Animal Coproducts Research Unit, Wyndmoor, Pennsylvania, United States of America

The epidemic of bovine spongiform encephalopathy (BSE) has led to a world-wide drop in the market for beef by-products, such as Meat-and-Bone Meal (MBM), a fat-containing but mainly proteinaceaous product traditionally used as an animal feed supplement. While normal rendering is insufficient, the production of biodiesel from MBM has been suggested to destroy infectivity from transmissible spongiform encephalopathies (TSEs). In addition to producing fuel, this method simultaneously generates a nutritious solid residue. In our study we produced biodiesel from MBM under defined conditions using a modified form of alkaline methanolysis. We evaluated the presence of prion in the three resulting phases of the biodiesel reaction (Biodiesel, Glycerol and Solid Residue) in vitro and in vivo. Analysis of the reaction products from 263K scrapie infected MBM led to no detectable immunoreactivity by Western Blot. Importantly, and in contrast to the biochemical results the solid MBM residue from the reaction retained infectivity when tested in an animal bioassay. Histochemical analysis of hamster brains inoculated with the solid residue showed typical spongiform degeneration and vacuolation. Re-inoculation of these brains into a new cohort of hamsters led to onset of clinical scrapie symptoms within 75 days, suggesting that the specific infectivity of the prion protein was not changed during the biodiesel process. The biodiesel reaction cannot be considered a viable prion decontamination method for MBM, although we observed increased survival time of hamsters and reduced infectivity greater than 6 log orders in the solid MBM residue. Furthermore, results from our study compare for the first time prion detection by Western Blot versus an infectivity bioassay for analysis of biodiesel reaction products. We could show that biochemical analysis alone is insufficient for detection of prion infectivity after a biodiesel process.


Discussion Top Decontamination of pathogenic prions has turned out to be a challenging endeavor. Prions are known to be unusually resistant to common decontamination methods. BSE is believed to be a result of insufficient decontamination and rendering methods of ruminant coproducts that were used as animal feed. Although this led to a devastating feed-borne epidemic among cattle, a major concern here is the overwhelming evidence for the zoonotic transmission of bovine prions to humans [20]. Total elimination of TSEs requires methods that completely destroy any potential prion infectivity in a large scale format. Production of biodiesel from bovine fat and brain tissue has been proposed to be a useful tool for decontamination of prions resulting in safe biodiesel [21]. In our study we evaluated an inexpensive large scale method (in situ transesterification) for production of biodiesel for TSE decontamination potential. Furthermore we investigated potential infectivity present not only in the biodiesel but also in the two other phases developed from the process, a solid MBM residue and glycerol. The solid MBM residue is of particular interest for its potential as a nutritious feed additive for ruminants such as cattle. In our hands, under optimal conditions for transesterification, the solid MBM residue retained 7% of the initial triglyceride and 90% of the initial protein content [17]

The alkaline methanolysis method efficiently produced biodiesel from MBM spiked with hamster brain and the method eliminated PrPsc detection in all products as determined by Western blot. Our biochemical results are comparable to previous studies, at least with regards to the biodiesel and glycerol phase [15]. Biodiesel and glycerol products had no detectable infectivity in our long term animal assay (survival>200d). In contrast to the biodiesel and glycerol phase, we show that the remaining solid MBM residue that had been spiked with scrapie brain retained infectivity in our sensitive bioassay. All animals inoculated with the infected solid MBM residue developed scrapie. However, increased survival time suggests the reaction did reduce infectivity in solid MBM residue from 10-3 ID50 to 10-9 ID50 (a partial decontamination of ~6 logs), based on a standard hamster survival curve that we established in our laboratory according to previous reported results [18]. The broad distribution of time-to-death for these animals is likely due to uneven distribution of infectious material in the inoculum, as the residue produced a relatively coarse suspension in the syringe. We suggest that, in addition to disinfection by the alkaline methanolysis reaction, we observe significant partitioning of infectivity, from the liquid phases into the solid residue. Another possible explanation for increased survival of animals inoculated with the solid MBM residue could be a high binding affinity of the prion protein to MBM and thus a sustained release from MBM in the brain. A phenomenon like this was described previously for prion binding to soil minerals [22]. In our study, when spiked into MBM, PrPsc was only detectable by Western Blot after boiling of sample in detergent. On the other hand we could show that control animals that received infected MBM not subjected to the reaction (MBM sc) developed disease in a time frame comparable to a standard scrapie brain homogenate.

Our results clearly show that Western Blot detection alone is insufficient to conclude on the absence of infectious prion, particularly when assessing a grossly heterogeneous sample such as MBM. This study illustrates that lack of prion detection in vitro does not necessarily exclude infectivity as determined by bioassay.

Furthermore the residual scrapie infectivity detected in the solid MBM residue probably limits the use of ruminant MBM as a feed additive to only non-ruminants, such as fish and fowl, as they are not susceptible to TSEs. Relatively minor variations of this reaction (e.g., more heat and/or alkali) may prove fully effective for complete destruction of infectivity in the solid MBM residue, but must be cost-effective if suspect MBM is to be considered as a ruminant feed additive.

Citation: Bruederle CE, Hnasko RM, Kraemer T, Garcia RA, Haas MJ, et al. (2008) Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production. PLoS ONE 3(8): e2969. doi:10.1371/journal.pone.0002969

Editor: Neil Mabbott, University of Edinburgh, United Kingdom

Received: April 21, 2008; Accepted: July 24, 2008; Published: August 13, 2008

This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.

Funding: CRIS 5325-32000-007-00D and CRIS 5325-32000-008-00D

Competing interests: The authors have declared that no competing interests exist.

* E-mail: cathrin.bruederle@gmail.com


Wednesday, December 29, 2010

CWD Update 99 December 13, 2010


Thursday, February 10, 2011

CWD ILLINOIS UPDATE FEBRUARY 2011 Locations of CWD-Positive Deer - Updated 2/07/2011


Thursday, February 10, 2011

Chronic Wasting Disease Found In A White-Tailed Deer In Maryland


Wednesday, February 09, 2011

CWD Minnesota deer feeding ban covering Dodge, Goodhue, Olmsted, and Wabasha counties will become effective Feb. 14, 2011


Tuesday, January 25, 2011

Minnesota, National Veterinary Services Laboratory in Ames, Iowa, has confirmed CWD case near Pine Island


Monday, February 14, 2011


Journal of Wildlife Diseases, 47(1), 2011, pp. 78-93 © Wildlife Disease Association 2011


Thursday, February 10, 2011

TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY REPORT UPDATE CANADA FEBRUARY 2011 and how to hide mad cow disease in Canada Current as of: 2011-01-31


Friday, February 18, 2011



Saturday, January 29, 2011

Atypical L-Type Bovine Spongiform Encephalopathy (L-BSE) Transmission to Cynomolgus Macaques, a Non-Human Primate

Jpn. J. Infect. Dis., 64 (1), 81-84, 2011


Friday, February 11, 2011

Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues


Wednesday, February 16, 2011




Thursday, February 17, 2011

Environmental Sources of Scrapie Prions


Tuesday, January 18, 2011

Agent strain variation in human prion disease: insights from a molecular and pathological review of the National Institutes of Health series of experimentally transmitted disease


Wednesday, January 19, 2011

EFSA and ECDC review scientific evidence on possible links between TSEs in animals and humans Webnachricht 19 Januar 2011


Transmissible Spongiform Encephalopathy and the O.I.E.

OIE Terrestrial Animal Health Standards Commission / September 2010

The EU takes note of the fact that atypical scrapie is not an OIE listed disease. Nevertheless, it will remain notifiable in the EU. Moreover it must be stressed that any emergence of this disease should be notified to the OIE by Members and that scientific data should continue to be gathered.


Zoonotic Potential

Has transmission to humans been proven? (with the exception of artificial

circumstances) AND

Is human infection associated with severe consequences? (death or prolonged illness)


Saturday, December 18, 2010

OIE Global Conference on Wildlife Animal Health and Biodiversity – Preparing for the Future (TSE AND PRIONS) Paris (France), 23-25 February 2011

I see again that the OIE has done little to help eradicate all animal TSE from the globe, and in fact in my opinion, have help enhance the spread of BSE and other animal TSE globally by their industry friendly regulations. I tried to warn the OIE in 2002 about CWD and the potential, but very real threat of CWD to humans. I was told that they were seriously considering this. what happened ? NOW, the OIE and the USDA collaborate to make legal the trading of all strains of atypical BSE legal, and in fact have done so with the atypical scrapie, when science has made perfectly clear the risk factors to humans and other species. I have said it once (see below), and i will say again ;

"THE OIE has now shown they are nothing more than a National Trading Brokerage for all strains of animal TSE. AS i said before, OIE should hang up there jock strap now, since it appears they will buckle every time a country makes some political hay about trade protocol, commodities and futures. IF they are not going to be science based, they should do everyone a favor and dissolve there organization."

JUST about every country that went by the infamous O.I.E. B.S.E. guidelines, most all came down with B.S.E. ...TSS

NOW, some history on the failed OIE BSE/TSE policy, and why the OIE allowed BSE and other TSE to spread around the globe $$$


i proposed to OIE years ago to include CWD. but with these new atypical case of TSE showing up in cattle and sheep, it will be interesting to see how the OIE handles the USA demands on weakening the BSE/TSE regs for exporting countries;

Date: Fri, 12 Jul 2002 16:11:42 -0700

Reply-To: B S E-l

Sender: Bovine Spongiform Encephalopathy

From: TSS

Subject: CWD/USA — CWD/OIE?


Greetings List Members,

speaking with someone at the OIE about my concerns with CWD and the non-testing for TSEs in USA cattle, i find it very sad that the OIE does not follow CWD related issues. BUT, they voice my same concerns and said changes are in the makings. sadly, the changes will take about 2 years?


''I agree with you Dr Terry. The OIE, namely the International Animal Health Code Commission is working on making proposals to Member Countries to change the OIE lists so to avoid some the problems mentioned in you e-mail. This will take at least two years before adoption by the International Committee.''


two years is a very long time, on an issue of such importance to both humans and animals...

kind regards, terry


PAGE 25 Transmission Studies Mule deer transmissions of CWD were by intracerebral inoculation and compared with natural cases resulted in a more rapidly progressive clinical disease with repeated episodes of synocopy ending in coma. One control animal became affected, it is believed through contamination of inoculam (?saline). Further CWD transmissions were carried out by Dick Marsh into ferret, mink and squirrel monkey. Transmission occurred in all of these species with the shortest incubation period in the ferret...


Saturday, December 18, 2010

OIE Global Conference on Wildlife Animal Health and Biodiversity - Preparing for the Future (TSE AND PRIONS) Paris (France), 23-25 February 2011


now, what about iatrogenic CJD i.e. friendly fire and or the pass if forward mode of transmission, from all of the above ???

Friday, February 11, 2011

Creutzfeldt-Jakob disease (CJD) biannual update (2010/1) Emerging infections/CJD


Saturday, February 12, 2011

Another Pathologists dies from CJD, another potential occupational death ?


Monday, February 7, 2011

FDA's Currently-Recommended Policies to Reduce the Possible Risk of Transmission of CJD and vCJD by Blood and Blood Products 2011 ???


Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA 77518



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