Tuesday, August 26, 2008

CWD Stakeholder Advisory Group Wednesday, August 22, 2007 11:31 AM



hello Mr. Crabtree and all Michigan hunters,

(please note my comments to Mr. Crabtree will be in bold letters below. ...TSS)

Rancid Crabtree Master Sportsman

Please don't get carried away with this CWD thing


Rancid Crabtree wrote ;

Been there, done that! I have been involved with the CWD thing here in WI for some time now. I will be more than happy to answer any questions that I am able to. I sat on our State's CWD Stakeholder committee and spent a good deal of time going through all the science and research and data. The briefings from the UW science team were very enlightening.

YEP, and i sent a great deal of data to all that was on that board. sadly, some of the data went in one ear and out the other ;

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

From: "Terry S. Singeltary Sr." To: Cc:

Sent: Wednesday, August 22, 2007 11:31 AM Subject: re-Outdoors: CWD experts address first meeting of advisory committee

re---Outdoors: CWD experts address first meeting of advisory committee Tim Eisele - 8/22/2007 10:46 am

Why should we care?



----- Original Message ----- From: "Terry S. Singeltary Sr." To: Cc: ; ; ; ; ; ; ; ; ; ; ; Sent: Thursday, August 16, 2007 8:30 PM Subject: Pathobiology and diagnosis of animal transmissible spongiform encephalopathies: current knowledge, research gaps, and opportunities

Hello CWD Stakeholder Advisory Group,

A kind greetings from Bacliff, Texas!

i have wasted some decade it seems on human and animal transmissible spongiform encephalopathies of humans and animals.

before your upcoming meeting, i urge you to read some data on CWD, you may not have been aware of.

I wish to send you the following data on CWD. Please use as you wish. i say now, and i say again almost a decade later, cwd is but a small part, of a much larger problem, one that is not going away anytime soon. ...

........good luck!

kindest regards, terry

----- Original Message ----- From: "Terry S. Singeltary Sr." To: Sent: Saturday, August 11, 2007 3:36 PM Subject: [BSE-L] Pathobiology and diagnosis of animal transmissible spongiform encephalopathies: current knowledge, research gaps, and opportunities

Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies Location: Virus and Prion Diseases of Livestock

Title: Pathobiology and diagnosis of animal transmissible spongiform encephalopathies: current knowledge, research gaps, and opportunities


Kehrli, Marcus O`rourke, Katherine Hamir, Amirali Richt, Juergen Nicholson, Eric Silva, Christopher Edelman, Daniel - FOOD AND DRUG ADMINISTRAT Gay, Cyril

Submitted to: Government Publication/Report Publication Type: Government Publication Publication Acceptance Date: May 1, 2007 Publication Date: July 1, 2007

Citation: Kehrli, Jr., M.E., O'Rourke, K.I., Hamir, A.N., Richt, J.A., Nicholson, E.M., Silva, C.J., Edelman, D., Gay, C.G. 2007.

Pathobiology and diagnosis of animal transmissible spongiform encephalopathies: current knowledge, research gaps, and opportunities [government white paper]. Beltsville, MD: Interagency Working Group on Prion Science, Subcommittee on Pathobiology and Diagnostics. USDA, Agriculture Research Service. 33 p.

Technical Abstract:

Transmissible spongiform encephalopathies (TSEs) are fatal neurologic diseases that can affect several animal species and human beings. There are four animal TSE agents found in the United States: scrapie of sheep and goats; chronic wasting disease (CWD) of deer, elk, and moose; transmissible mink encephalopathy (TME) and bovine spongiform encephalopathy (BSE). Although the animal TSEs do not cause major death losses among US livestock populations, they are important because of international trade issues. The experience of the United Kingdom and Europe in dealing with the vast majority of the world's BSE cases, serves as a reminder of the need for continuing vigilance in monitoring risks for public health and research to answer remaining questions around the pathogenesis and transmission of these diseases. There remain questions on 1) cross-species transmissibility of TSEs in livestock and wildlife; 2) the pathobiology of TSEs in natural and secondary hosts; pathogenesis and transmission of CWD; and 4) pathogenesis and ante mortem detection of typical and atypical BSE. Our understanding of the pathogenesis and transmission of these diseases continues to evolve as ongoing, global TSE research efforts focus on defining tissue sites of abnormal prion accumulation, routes of infection, methods of strain differentiation, genetics of susceptibility and ante-mortem diagnostics. In this paper, a Subcommittee on Pathobiology and Diagnostics of TSEs for an Interagency Working Group on Prion Science summarizes the science of animal TSEs in order to identify knowledge gaps for the purpose of prioritizing animal prion research needs. Because of substantial losses involving international trade and potential risk for interspecies transmission to susceptible livestock and possibly humans, the presence of BSE, CWD, scrapie and TME in the United States presents a liability to U.S. domestic and alternative livestock industries. In addition, the proven risk of BSE to agriculture and public health from subclinical or clinically sick animals requires science-based surveillance for any silent, unrecognized epizootic expansions of these diseases in populations of animals that could either directly or indirectly affect food animals. CWD is an example of an uncontrolled expanding epidemic that threatens not only cervids but possibly other livestock. CWD also has elicited public health surveillance programs to monitor for scientific evidence of a prion disease in humans that consume venison. Therefore, some of the research needs are precautionary, but the risks to animal and human health from being caught unaware are high. Efforts are being made by both federal and state regulatory agencies to eradicate scrapie and CWD, and to determine the prevalence of BSE. The effectiveness of these programs will depend heavily on having accurate information about the nature of these diseases, not only in the original hosts, but also in other species that may be in contact with infected animals.


Summary of Selected Disease Events January-March 2007

Scrapie: Nor98-like-Wyoming On March 16, 2007, the USDA Animal and Plant Health Inspection Service (APHIS) notified stakeholders that an aged female sheep had tested positive for scrapie, consistent with the Nor98 type. The ewe was slaughtered in Michigan, where it was tested as part of USDA's ongoing regulatory scrapie slaughter surveillance program. The ewe was traced back to a flock in Wyoming. This is the first time this particular type of scrapie has been found in the United States. The Nor98 type of scrapie is uncommon even in Europe, with fewer than 300 similar cases diagnosed since it was identified in 1998.


ORAL-04 EPIDEMIOLOGY OF CHRONIC WASTING DISEASE IN NORTH AMERICAN CERVIDS M. W. Miller Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, Colorado, USA. Chronic wasting disease (CWD) occurs naturally in North American deer (Odocoileus spp.), wapiti, and moose (collectively called "cervids"). CWD presently occurs in scattered foci throughout North America, both in the wild and in commercial facilities. CWD is contagious among its natural hosts, and epidemics can persist under both captive and free-ranging conditions, resulting in remarkably high infection rates. The precise mechanism of contagion remains unclear, although accumulations of disease-associated prion protein (PrPCWD) in lymphatic tissues associated with the gastrointestinal tract suggest shedding via feces and perhaps saliva. Analyses of epidemic data suggest that indirect (animal-environment-animal) transmission may be the dominant force in epidemic dynamics, and the CWD agent has been shown to persist in environments contaminated by excreta or carcass remains for years. Variation in cellular prion protein appears to influence CWD pathogenesis, and may provide a biological mechanism for emergence of variant strains within and among the four naturally susceptible species. The long-term implications of CWD for public, livestock, and wildlife health remain uncertain. Unfortunately, limitations of existing technology available to combat prion diseases make control of CWD ineffective or infeasible under most conditions. 23

ORAL-19 IINTERSPECIES PRION TRANSMISSION IS CONTROLLED BY CONFORMATIONAL COMPATIBILITY BETWEEN PRPSC AND HETEROTYPIC PRPC K.M. Green*1, S.R. Browning*1,6, T.S. Seward2, M. Green4, E.A. Hoover5, G.C. Telling1,2,3,7 1Department of Microbiology, Immunology and Molecular Genetics, 2Sanders Brown Center on Aging,3Department of Neurology, 4UK Transgenic Facility University of Kentucky, Lexington, Ky USA. 5Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Co, USA 6Present address: Department of Infectology, Scripps Research Institute, Jupiter, Florida, USA 7To whom correspondence should be addressed:gtell2@uky.edu * These authors contributed equally The threats to humans and livestock from interspecies prion transmission are difficult to assess because the factors controlling this process remain uncertain. To address this we have used transgenic mouse models to understand the roles played by PrP primary structure, prion strains and the species specificity of protein X in controlling interspecies prion infection in the context of cervid transmission barriers. Cervid prions are of particular concern because chronic wasting disease (CWD) of North American and South Korean cervids is the only recognized prion disease of wild animals and its increasing geographic range, contagious nature, and environmental persistence have raised concerns about prion dissemination and the potential for further interspecies transmission. We show that conformational compatibility of PrPSc in a prion strain and PrP primary structure in a new host is the most important determinant of interspecies prion transmission barriers. Although prion strains can acquire totally new host range properties following heterologous conversion of PrPP C in a new host, the strain-related biochemical properties of PrPSc may remain relatively stable. We also show that the cervid PrP polymorphism at residue 132, which is equivalent to the human PrP 129 polymorphism, is a crucial determinant of cervid prion transmission and has a profound controlling effect on PrPSc-related prion strain properties. Our transgenic approaches modeling trans-species prion susceptibility in cervids also speak to the possible origins of CWD since cervid transgenic mice are also vulnerable, to varying degrees, to sheep scrapie prions, the degree of susceptibility being strain related. One particularly well-characterized sheep scrapie isolate, SSBP/1, caused disease as efficiently as CWD prions from diseased deer or elk. Finally, while transmissions in transgenic mice based on the protein X model of prion propagation produced chimeric prions, passage of which resulted in novel cervid prions with an extended host range compared to CWD-cervid prions, the unexpected susceptibilities of such mice to CWD and mouse prions are inconsistent with the previously hypothesized role of protein X in prion propagation.

GEN-13 PRION PROTEIN GENES AFFECT SUSCEPTIBILITY OF CERVIDS TO CHRONIC WASTING DISEASE C. Johnson1, J. Johnson1, J.P. Vanderloo1, D. Keane2, P. Bochsler2, J.M. Aiken1, D. McKenzie1 1Department of Animal Health and Biomedical Sciences and 2Wisconsin Veterinary Diagnostic Laboratory, University of Wisconsin, Madison, WI, USA mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:mckenzie@svm.vetmed.wisc.edu The primary sequence of the prion protein affects susceptibility to transmissible spongiform encephalopathies (TSE; prion disease) in mice, sheep and humans. The Prnp sequence of freeranging, Wisconsin white-tailed deer was determined and the Prnp genotypes of CWD-positive and - negative deer compared. Six amino acid (AA) changes were identified; two of which were located in pseudogenes. Two alleles, a glutamine to lysine polymorphism at codon 226 and a single octapeptide repeat insertion into the pseudogene, have not been previously reported. The predominant alleles, wild-type (glutamine at AA95, glycine at AA96 and glutamine at AA226) and a glycine to serine polymorphism at AA96 (G96S), comprise almost 98% of the Prnp alleles in the Wisconsin white-tailed deer population. Comparison of the allelic frequencies in the CWD-positive and -negative deer suggests that G96S and a glutamine to histidine polymorphism at AA 95 (Q95H) are linked to a reduced susceptibility to CWD. The G96S allele does not, however, provide complete resistance, as a CWD-positive G96S/G96S deer was identified. The G96S allele is also linked to slower progression of disease in CWD-positive deer based on the deposition of PrPCWD in the obex region of the medulla oblongata. To further determine the effect of variations of the cervid Prnp alleles on susceptibility, deer with known Prnp genotypes were orally dosed with CWD inocula prepared from wild-type/wild-type homozygous animals. The experimentally infected wild-type/wild-type animals have succumbed to disease, animals heterozygous for Prnp alleles have not.

PA-03 PRIONS IN SKELETEL MUSCLE OF CWD INFECTED DEER R.C. Angers*1, S.R. Browning*1,6, T.S. Seward2, C.J. Sigurdson4, 7, M.W. Miller5, E.A. Hoover4, G.C. Telling1, 2, 3, 8 1Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536, 2Sanders Brown Center on Aging, University of Kentucky, 3Department of Neurology, University of Kentucky, 4Department of Microbiology, Immunology and Pathology, Colorado State University, 5Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, CO 80526; 6 Present address: Department of Infectology, Scripps Research Institute, 5353 Parkside Drive, RF-2, Jupiter, Florida, 33458; 7 Present address: Institute of Neuropathology, University of Zurich, Schmelzbergstr 12, 8091 Zurich, Switzerland; 8 To whom correspondence should be addressed: e-mail: gtell2@ uky.edu; * These authors contributed equally to this work The zoonotic potential of chronic wasting disease (CWD) has become a public health concern since the transmission of bovine spongiform encephalopathy (BSE) prions to humans resulting in variant Creutzfeldt- Jakob disease (vCJD). Studies in mice, sheep and humans indicated that PrPSc could be detected in the skeletal muscles. Since the most probable route of human exposure to CWD is through consumption or handling of meat from infected animals, it is important to assess whether skeletal muscle from affected cervids harbors prions. CWD-susceptible Tg(CerPrP) mice were intracranially inoculated with brain and matched skeletal muscle homogenates from moribund as well as non-infected control deer. Tg mice inoculated with either brain or muscle homogenates from CWD-infected deer developed clinical illness with characteristic prion disease symptoms and the brains of recipients accumulated cervid PrPSc. The mean incubation times for animals inoculated with brain material ranged between 231 and 283 days, whereas mice receiving muscle tissue had average incubation periods between 360 and 492 days. Tg mice inoculated with material from CWD-negative deer did not develop prion disease or accumulate PrPSc. Brain and muscle samples used to inoculate Tg(CerPrP) mice were analyzed for the presence of PrPSc. Brain samples producing the shortest incubation times had levels of PrPP Sc detectable by Western blotting in 25 µg total protein, whereas PrPSc P was detectable only after sodium phosphotungstate (NaPTA) precipitation of 0.5 mg for isolates with the longest incubation periods. No protease-resistant material was detected in muscle when 50 mg total protein was precipitated with NaPTA and analyzed by Western blot. Although a possible role of prion strain variability cannot currently be dismissed, these results suggest variable prion titers in the CNS and skeletal muscle from different CWD-infected deer in the same phase of disease.



sporadic cjd



Colorado Surveillance Program for Chronic Wasting Disease Transmission to Humans (TWO SUSPECT CASES, see GSS)


snip...full text of my email to the CWD Stakeholder Advisory Group is too long, and most all of it was posted here. ...TSS

Mr. Crabtree, such a statement, coming from someone in a state that has been hurt deeply by CWD as Wisconsin, someone that sat on that committee, a state that has NOT been able to eradicate CWD in decades, a statement such as 'Please don't get carried away with this CWD thing', is probably exactly why your state is still in the shape it's in with regards to CWD.

SO, I kindly ask you Mr. Crabtree, would you eat a deer brain sausage from a CWD infected area, and then feed it to your kids?

Also Mr Cabtree, What would happen if we did nothing to manage CWD?

Because there is no evidence of genetic resistance

to CWD in deer, the idea that it could simply “burn itself out” is nearly impossible. A simulation model suggests

that if left unmanaged over the next ten to thirty years, CWD will spread widely throughout Wisconsin and

increase in prevalence to more than 40 percent of adult deer. Colorado’s situation supports this model because

prevalence in mule deer on some local winter ranges there now exceeds 25-30 percent. To put this in perspective,

in some sections of Wisconsin’s core area prevalence is as high as 8-12 percent. In addition, the known affected

area of Colorado and Wyoming has expanded more than one hundred miles to the

west and northwest during the past five years.


Wildlife disease experts have concluded that in the absence of management intervention, CWD will most likely increase in prevalence and distribution. There is no evidence that CWD will “burn itself out” if left alone. A simulation model suggests that if left unmanaged over the next 10-30 years, CWD will spread quickly throughout Wisconsin and will substantially increase in prevalence to more than 40 percent of adult deer. Simulations of effects on deer population size in the CWD affected area depend on the assumptions made about the transmission process, but all models show a moderate to substantial long-term reduction in deer population density. The model simulations are consistent with recent findings in Colorado that have shown increases in prevalence over the past few years in numerous local populations. Prevalence on some local winter ranges now exceeds 25-30 percent. In addition, the known affected area in both Colorado and Wyoming has expanded to the west and northwest more than 100 miles during the past five years.



In one contaminated research facility, more than 90% of the deer housed for more than two years contracted CWD.

Such infection rates in wild deer populations would have devastating effects. .......


Northwestern Nebraska: In 2001, active surveillance in the vicinity of a CWD-positive

captive elk herd in Sioux County disclosed several infected white-tailed deer. On the

ranch with the positive elk, a CWD infection rate of approximately 50% was found

among 179 wild deer inside a high fence enclosure built on the property at the time the

elk enclosure was constructed in the early 1990s.



5. Predicted population effects on free-ranging elk based on captive elk chronically exposed to the CWD prion. Forty-three female elk calves were trapped at the National Elk Refuge and transported to Sybille in February 2002. Elk were housed in pens, assumed to be environmentally contaminated with the CWD prion. Elk will be held throughout their lifetimes. Elk dying will be examined and cause of death determined. From these data, it will should be possible to model free-ranging elk mortality and population dynamics under extreme circumstances of CWD prion exposure and transmission. As of December 2005 (46 months post capture), 11 of 43 elk have died due to CWD. This compares to 100% mortality in less than 25 months in elk orally inoculated with different dosages of the CWD prion.


Additionally, recent research indicates that there may be pockets of infection with very high rates of the CWD within the larger endemic area. Also, mature bucks appear to be infected at a higher rate than other portions of the population.

Upon learning that a number of captive whitetail taken inside the Sioux County game ranch tested CWD positive, and concerned about the Kimball County results, Commission staff in January 2002 began a culling operation within a 15-mile radius of the Sioux County game ranch. Of 113 wild animals taken in that culling operation, nine tested positive for the disease, for an overall infection rate of nearly eight percent. Of those testing positive, five were culled within two miles of the game ranch boundaries, two were culled within two to five miles, and two were culled within five to seven miles.

At the same time, Commission staff culled 172 mule and white-tailed deer from within the captive game ranch in Sioux County. Of 154 test results received, 79 animals tested positive. An additional culling, in cooperation with the South Dakota Department of Game, Fish and Parks, along our common border resulted in a sample size of 193 deer with all being negative.


In states where the disease has been present for more than a decade, the prevalence of CWD in wild deer populations has been observed at 1%-15%. This rate, by itself, is not sufficient to cause reductions in deer population size. However, these observations occurred in states where deer populations do not achieve the high densities that occur in New York and Wisconsin. In captive deer herds, CWD can reach remarkably high infection rates. In one contaminated research facility, more than 90% of the deer housed for more than two years contracted CWD. Such infection rates in wild deer populations would have devastating effects. Hunting is the wildlife manager’s most important tool for regulating deer abundance. High deer population densities lead to more rapid spread of CWD in an infected herd. Consequently, programs to reduce the deer population, which may include increased harvest of female deer, will be implemented in areas where CWD has been detected.


Chronic wasting disease can reach remarkably high prevalence in captive cervid populations. In one infected research facility, more than 90% of mule deer resident for more than 2 years died or were euthanized while suffering from CWD. Recently, high CWD prevalence (about 50%) has been demonstrated in white-tailed deer confined in association with an infected Nebraska elk farm. Among captive elk, CWD was the primary cause of adult mortality (5 of 7, 71%; 4 of 23, 23%) in 2 research herds, and high prevalence (59%) was detected in a group of 17 elk slaughtered from an infected farm herd. To estimate prevalence in infected free-ranging populations, tissues from deer and elk harvested by hunters in CWD-endemic areas have been collected and examined at random. Within endemic areas, prevalence of preclinical CWD has been estimated at less than 1% in elk and less than 1% to 15% in mule deer. Modeled CWD epidemics failed to achieve a steady-state equilibrium in infected deer populations, suggesting that CWD may lead to local extirpations of infected deer populations if left unmanaged. (Excerpted and modified from: Williams, Elizabeth S., Michael W. Miller, and E. Tom Thorne. Chronic Wasting Disease: Implications and Challenges for Wildlife Managers. Transactions of the 67th North American Wildlife and Natural Resources Conference. In Press.)


Rancid Crabtree wrote ;

As I said, I will try to answer anything you throw at me from a deer hunters perspective but know right now that CWD is not a threat to humans, cattle or even the majority of deer. WI has had CWD for almost 30 years and it remains isolated to only a portion of the state and that area, we named the CWDMZ (Management zone) has an infection rate of less than 3%

Rancid Crabtree wrote ;


Mr. Crabtree, TO make such a bold statement, about a disease (TSE), where some strains in some species can incubate for up to 55 years, with a TSE as CWD, that will transmit to primate and other species in the lab, a disease where there still remains so many 'unknowns', I find this statement disturbing. just my opinion. you have your opinions and sources, i have mine. BUT, I can guarantee you that others in the medical and government research are very much cautiously concerned with this. but let's just look at some science on this topic. I think most everyone on this board are capable of ciphering this science out, from the transmission studies of new and old from different TSEs. I am sorry for this long post, I will try and keep this short, and if anytime, anyone of you gets tired of this CWD data and wants to just throw you hands up in the air and say ''Please don't get carried away with this CWD thing'', I will sadly and kindly move on. i could have posted my comment to a single blog, and then posted the blog url to here, but i think this science needs to be displayed here. seems on some of these state CWD boards that i have been on for some time, kindly ban me from their site once CWD has been found. I would like that not to happen here on the michigan-sportsman.com/. I am not here to do nothing but show you all the science, what some seem to overlook for whatever reasons. i could have easily put all this in a single url for you, and would if need be, but i think it is important to post these studies in part or whole, and have them on these CWD sites. from the beginning, michigan-sportsman.com/ site here has been very kind about letting us speak about CWD, debate, and post our data. please dont' change just because Michigan has now documented CWD. i am pretty much done for now anyway, you have the data. now you must make some very serious decisions. i know it's a pipe dream, but let's pray it is kept only to the deer farms and has not escaped to the wild. ...thank you, kind regards, terry


Quantifying the Species Barrier in Chronic Wasting Disease by a Novel in vitro Conversion Assay

Li, L1; Coulthart, MB2; Balachandran, A3; Chakrabartty, A4; Cashman, NR1 1University of British Columbia, Brain Research Centre, Canada; 2Public Health Agency of Canada, National Microbiology Laboratory, Canada; 3Animal Diseases Research Institute, Canada Food Inspection Agency, National Reference Laboratory for Scrapie and CWD, Canada; 4Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Canada

Background: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy that can affect North American cervids (deer, elk, and moose). Although the risk of CWD crossing the species barrier and causing human disease is still unknown, however, definite bovine spongiform encephalopathy (BSE) transmission to humans as variant CJD (vCJD), it would seem prudent to limit the exposure of humans to CWD.

Aim: In view of the fact that BSE can be readily transmitted to non-bovid species, it is important to establish the species susceptibility range of CWD.

Methods: In vitro conversion system was performed by incubation of prions with normal brain homogenates as described before, and protease K (PK) resistant PrP was determined by immunoblotting with 6H4 monoclonal prion antibody.

Results: Our results demonstrate that PrPC from cervids (including moose) can be efficiently converted to a protease-resistant form by incubation with elk CWD prions, presumably due to sequence and structural similarities between these species. Interestingly, hamster shows a high conversion ratio by PrPCWD. Moreover, partial denaturation of substrate PrPC can apparently overcome the structural barriers between more distant species.

Conclusions: Our work correctly predicted the transmission of CWD to a wild moose. We find a species barrier for prion protein conversion between cervids and other species, however, this barrier might be overcome if the PrPC substrate has been partially denatured in a cellular environment. Such an environment might also promote CWD transmission to non-cervid species, *** including humans. Acid/GdnHCl-treated brain PrPC was a superior substrate for the in vitro conversion than PrPC treated at physiological pH. This has implications for the process by which the prion protein is converted in disease.


Review 2006-2007

Chronic wasting disease

Christina J. Sigurdson ., Adriano Aguzzi Universitäts Spital Zürich, Institute of Neuropathology, Department of Pathology, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland Received 13 July 2006; received in revised form 6 September 2006; accepted 12 October 2006 Available online 18 October 2006 Abstract Until recently, chronic wasting disease of cervids, the only prion disease affecting wildlife, was believed to be geographically concentrated to Colorado and Wyoming within the United States. However, increased surveillance has unveiled several additional pockets of CWD-infected deer and elk in 12 additional states and 2 Canadian provinces. Deer and elk with CWD have extensive aggregates of PrPSc not only in the central nervous system, but also in peripheral lymphoid tissues, skeletal muscle, and other organs, perhaps influencing prion shedding. Indeed, CWD is transmitted efficiently among animals by horizontal routes, although the mechanism of spread is unknown. Genetic polymorphisms in the Prnp gene may affect CWD susceptibility, particularly at codon 225 (S/F) in deer and codon 132 (M/L) in elk. Since CWD infects free-ranging animals and is efficiently spread, disease management will be a challenge. © 2006 Elsevier B.V. All rights reserved. Keywords: CWD; Deer; Elk; Prion; TSE; Review 1. A chronicle of CWD A prion disease of free-ranging wildlife, chronic wasting disease

1. A chronicle of CWD A prion disease of free-ranging wildlife, chronic wasting disease (CWD) affects mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), Rocky Mountain elk (Cervus elaphus nelsoni) [1], and moose (Alces alces shirasi) [2], all members of the family Cervidae. CWD was first noted in 1967 within a research facility in Fort Collins, Colorado where captive mule deer used for nutrition research were reported with a body wasting syndrome [2]. After more than a decade of uncertainty about the etiology of CWD, pathologists Elizabeth Williams and Stewart Young recognized the brain lesions as those of a transmissible spongiform encephalopathy (TSE) in 1978, and CWD was subsequently demonstrated as a prion disease not only by the classic neuronal perikaryonic vacuoles [3], but also by the accumulation of aggregated prion protein [4] (Fig. 1) as well as prion infectivity in the brain [5]. In the late 1970s and early 1980s, CWD was detected in two zoological collections, in Wyoming and in Canada [6]. Beginning in 1981, cases of CWD were discovered in wild deer and elk on the eastern slope of the Rocky Mountains and extending out on the plains following river valleys within Colorado and Wyoming [7,8]. By 1996, CWD was first detected in Canada's farmed elk, and soon thereafter in the US elk industry, although it may have occurred in this industry far earlier. More recently, CWD-infected ranched elk have been discovered in several other US states and in South Korea [9,10] raising international awareness and concern regarding CWD. The origin of CWD remains an enigma (Table 1). 2. Epidemiology and disease management Based on published and unpublished estimates, there may be well over 30 million cervids in North America [11]. Prior to 2000, it was known that CWD had spread in part through transport of captive deer and elk and movements of free-ranging animals, but its distribution was believed to be limited to a 40,000 km2 region of northern Colorado and southern Wyoming [1,8], with a small number of cases in Canada [1,6]. CWD surveillance has recently been initiated in other states and provinces, and the results have been astonishing. CWD-infected cervids have been reported in 12 additional states, extending east to New York andWest Virginia, as well as in 2 Canadian provinces


(Fig. 2). The distribution pattern is not in contiguous zones consistent with natural movement of free-ranging animals, but instead concentrated in focal hotspots of varied size separated by large distances (Fig. 2). Wisconsin has dense white-tailed deer populations (15–20 deer/km2) with a prevalence of up to 13% of the bucks in some regions [12]. The origins of these recent outbreaks remain under investigation, but in some cases spillover from infected game farms seems a plausible explanation. The appearance of CWD in wild cervids presents significant challenges to disease control or eradication due to (i) the extensive geographic range of North American deer and elk, (ii) the logistical difficulty in applying ante-mortem diagnostic tests such as tonsil biopsy [13], and (iii) the inability to rid the environment of potential prion contaminated excreta.


CWD infects free-ranging animals, creating an enormously complex situation for controlling disease spread, particularly in light of our poor understanding of specific transmission routes and susceptibility of non-cervid species. In addition, prioninfected deer and elk will be consumed by scavengers and other carnivores, including mountain lions, foxes, raccoons, coyotes, as well as eagles and vultures. Domestic ruminants and other herbivores are likely exposed through CWD contaminated grazing areas, and conversely, wild ruminants are likely exposed to sheep scrapie. Species known to be susceptible to CWD by an extreme and unnatural exposure route, intracerebral inoculation, include ferrets [15], raccoons [16], other ruminants (discussed below), and squirrel monkeys [17]. Studies are ongoing to determine whether mountain lions (Puma concolor) are susceptible (M. Miller, personal communication and [18]).

Table 1 Inter-ruminant prion transmission experiments Host Inoculum Exposure route No. of infected/ no. of exposed Time to terminal disease Spongiform encephalopathy PrPSc detected by IHC and/or WB Reference Cattle Mule deer CWD+ brain Intracerebral (ic) 5/13 2–5 years Equivocal Yes [27] Cattle Cattle CWD from ic infection above Intracerebral 6/6 16.5 months No Yes [29] Elk Sheep scrapie Intracerebral 3/6* 3–4 years Yes Yes [31] * intercurrent death in 3 animals during first 2 years post-inoculation.

2.1. Transmission among cervids Of all the mammalian prion diseases, CWD is likely the most efficiently transmitted. In dense free-ranging deer populations, CWD prevalence can reach as high as 30%, however in captive herds, prevalence can climb to nearly 100% [2]. How is CWD transmitted with such efficiency? This question is arguably one of the biggest conundrums in the CWD field, and hypotheses range from spread via direct contact to exposure through grazing in areas contaminated by prion-infected secretions, excretions (saliva, urine, feces), tissues (placenta), or decomposed carcasses. Indeed, Miller et al. have shown that CWD-infected carcasses allowed to decay naturally in confined pastures can lead to CWD infections in captive deer [19]. Perhaps multiple exposure pathways can lead to an infection, nevertheless, horizontal spread of CWD is clearly occurring [20] and vertical transmission cannot be excluded. Conceivably the abundant PrPSc in tonsils and Peyer's patches [4] contributes to PrPSc shedding in saliva or feces. Nonetheless, environmental prion contamination underscores the difficulties of CWD eradication, a goal which is unlikely to be met for free-ranging cervid populations with the available management techniques. Indeed, CWD eradication is not a stated management goal for all western states. Inflammation may increase the risk of prion shedding in cervids. In prion-infected mice, follicular inflammation in the kidney directs prions to accumulate within lymphoid follicles [21] and intriguingly, leads to prion excretion into the urine of infected mice [22]. Even in natural sheep scrapie cases, follicular mastitis results in prion accumulation in the mammary gland [23]. It remains to be seen whether scrapie prions are then shed into the milk to infect nursing lambs. Because deer and elk also have a widespread prion assemblage within lymphoid tissues, it seems plausible that follicular inflammation may also lead to CWD prion build-up in nonlymphoid organs, potentially shifting shedding routes. It is unknown whether other types of inflammation, such as the granulomatous inflammation in the intestine seen in Johne's disease (Mycobacterium avium subsp. paratuberculosis) (affects ruminants, including deer and elk) or parasitic inflammation could lead to or perhaps increase prion excretion by fecal routes. Recent studies of prion disease in hamsters indicate the potential for prion shedding via saliva [24]. In hamsters intracerebrally (ic) exposed to scrapie, prions are transported centrifugally from brain to the tongue, and PrPSc deposits in muscle, nerve, taste buds, and epithelium, serving as a large potential reservoir for continual PrPSc shedding into saliva. In addition, PrPSc has been detected in the tongue of 7 of 10 sheep naturally infected with scrapie using both western blotting and immunohistochemistry techniques [25]. However, the tongue of CWD infected deer and elk has not yet been investigated for the presence of PrPSc or prion infectivity. Nevertheless, CWDinfected tonsils contain abundant PrPSc (Fig. 1) [26] and may also serve as a source for prion shedding into saliva. In light of the commonly shared salt licks and water sources in captivity, as well as licking behaviors of deer and elk, PrPSc transmission via saliva should be considered as suspect.

2.2. Transmission to livestock The capacity for CWD transmission to other species is clearly an area of great concern since potentially CWD-infected free-ranging animals are co-habitating with domestic ruminants. However, data on the risk for other wildlife species or domestic ruminants contracting the disease is steadily accumulating. Cattle have been challenged with CWD by 3 routes: (i) intracerebral (ic), (ii) oral, and (iii) via contact exposure to CWD-infected mule deer (co-habitation)[25, M. Miller, personal communication]. After 6 years, only cattle challenged by ic inoculation have developed disease. Five of thirteen animals (38%) developed prion infection after an incubation period of 2¨C5 years [27]. Secondary passage of the cattle CWD led to a decrease in incubation period to ¡«16 months with 100% attack rate (n=6) [28]. Perhaps surprisingly, cattle did not develop a spongiform encephalopathy, although PrPSc was clearly detected in brain by immunohistochemistry and Western blot. By comparison, ic-induced sheep scrapie infection in cattle resulted in 100% of cattle developing neurologic disease with PrPSc deposits in the brain (9/9) [29]. A targeted surveillance of 262 older cattle from a CWD endemic area in Colorado did not reveal any indication of a TSE [30]. Sheep are also susceptible to CWD after ic inoculation [2], but have not yet been challenged by oral routes. One goat developed TSE 6 years afterCWDinoculation and showed signs of intense pruritis and weight loss [6]. Elk have been challenged with sheep scrapie, and developed a spongiform encephalopathy with PrPSc in the brain detected by immunohistochemistry and western blot. Intriguingly, the histologic lesions and PrPSc deposits in the brain were indistinguishable from CWD in cervids [31]. As far as we know, deer have not been directly challenged with sheep scrapie, however this experiment may be interesting and at least addresses whether sheep scrapie could be an origin for deer CWD.

2.3. CWD and human susceptibility Several million deer and elk hunters consume venison in the US and Canada and there is no doubt that people have been exposed to CWD. Human susceptibility to CWD is still unclear, although we can be somewhat reassured in that there have been no large scale outbreaks with hundreds of human TSE cases in Colorado and Wyoming, where CWD has existed for decades. That said, diagnosis of potential new TSE strains has been hampered in that, up until recently, autopsies were not performed on suspect human TSE cases in many states due to biosafety concerns. This indicates that clinical TSE diagnoses in humans were not confirmed, nor was any strain typing done to look for the appearance of potentially subtle or unusual pathological or biochemical phenotypes of a new TSE strain. Fortunately, the autopsy rate for suspect cases is improving. At the National Prion Disease Pathology Surveillance Center at Case Western Reserve University (Cleveland, Ohio), CJD suspect cases are studied and classified by CJD subtype. Thus far, twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center, however, there have been no unusual or novel prion subtypes indicating the appearance of a new prion strain. [11,32]. Other indirect studies of human susceptibility to CWD, although limited in number, suggest that the risk is low. In biochemical conversion studies, Caughey et al. showed that the efficiency of CWD to convert recombinant human PrP into amyloid fibrils was low, but similar to that of both BSE and scrapie fibrils to do the same [33]. Recently Xie et al. have compared histopathology and PrPSc biochemical characteristics from deer and elk with that of humans with sporadic CJD cases that are methionine homozygous at codon 129 [34]. The PrPSc form is cleaved by proteinase-K at different sites depending on the conformation of the protein so can be used to aid determination of whether the PrPSc conformation is similar. For CWD, the unglycosylated PK-resistant PrPSc migrated at 21 kDa, similar to sCJD (MM1 subtype), the PK cleavage site was the same, occurring at residues 78 and 82 as assessed by Nterminal sequencing, and the conformational stability also showed no significant difference between elk CWD and sCJD MM1 cases. However, there were distinct glycoform patterns exhibited by two dimensional gel electrophoresis, suggesting that the elk CWD and human sCJD MM1 strains differ, although strain features, including histologic profile, target organs, and glycoform patterns, will not necessarily remain the same upon crossing species barriers [15,35,36]. Kong et al. studied the question of human susceptibility to CWD by inoculating transgenic mice expressing human PrP or elk PrP with elk CWD. Whereas the elk PrP expressing mice developed disease after only 118¨C142 days post-inoculation, human PrP expressing mice (129M) did not develop any features of TSE after >657 or >756 days [11].


In light of the discussion herein, one aspect of CWD research is crystal clear: there are many unsolved mysteries in this disease of wild animals. The sooner we understand basic disease factors such as CWD origins, mechanisms of spread, and species susceptibility, the more specifically we can target prevention and management programs.



AGUZZI et al 2008

Molecular Mechanisms of Prion Pathogenesis

Adriano Aguzzi, Christina Sigurdson, and Mathias Heikenwaelder Institute of Neuropathology, University Hospital of Z¨ urich, CH-8091 Z¨ urich, Switzerland; email: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:adriano.aguzzi@usz.ch, mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:mathias.heikenwaelder@usz.ch, mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:christina.sigurdson@usz.ch Annu. Rev. Pathol. Mech. Dis. 2008. 3:11-40 First published online as a Review in Advance on August 8, 2007 The Annual Review of Pathology: Mechanisms of Disease is online at pathmechdis.annualreviews.org This article's doi: 10.1146/annurev.pathmechdis.3.121806.154326 Copyright c 2008 by Annual Reviews. All rights

Annu. Rev. Pathol. Mech. Dis. 2008. 3:11-40 First published online as a Review in Advance on August 8, 2007 The Annual Review of Pathology: Mechanisms of Disease is online at pathmechdis.annualreviews.org This article's doi: 10.1146/annurev.pathmechdis.3.121806.154326 Copyright c 2008 by Annual Reviews. All rights reserved 1553-4006/08/0228-0011$20.00


Prion diseases are infectious neurodegenerative diseases occurring in humans and animals with an invariably lethal outcome. One fundamental mechanistic event in prion diseases is the aggregation of aberrantly folded prion protein into large amyloid plaques and fibrous structures associated with neurodegeneration. The cellular prion protein (PrPC) is absolutely required for disease development, and prion knockout mice are not susceptible to prion disease. Prions accumulate not only in the central nervous system but also in lymphoid organs, as shown for new variant and sporadic Creutzfeldt- Jakob patients and for some animals. To date it is largely accepted that prions consist primarily of PrPSc, a misfolded and aggregated â-sheet-rich isoform of PrPC. However, PrPSc may or may not be completely congruent with the infectious moiety. Here, we discuss the molecular mechanisms leading to neurodegeneration, the role of the immune system in prion pathogenesis, and the existence of prion strains that appear to have different tropisms and biochemical characteristics.


As an example in the field of human medicine, four cases of vCJD have been reported to be caused by blood transfusion (9- 11). This indicates that BSE prions can be recycled among humans, which has caused considerable alarm that the supply of bloodderived pharmaceuticals may be threatened (12). In particular, the report of a subclinical blood-derived vCJD infection in an individual carrying a heterozygote methionine/ valine polymorphism at codon 129 of the human PRNP gene (10) suggests that transmission of BSE prions to humans enhances their virulence and broadens the spectrum of susceptible recipients. In this respect, it has been demonstrated that polymorphisms at codon 129 of the human PRNP gene control susceptibility and incubation time in human patients (e.g., 129MM versus 129MV or 129VV drastically increases the susceptibility of humans to BSE prions). It was reported only recently that most individuals who suffered from kuru and were polymorphic at codon 129 showed incubation times longer than 50 years (13). Moreover, recent reports indicate that there is still a lot to be learned about the mechanisms of prion transmission (e.g., human to human or within scrapie-affected animal flocks) and prion tropism underlining the complex alternating distribution patterns of PrPSc (e.g., PrPSc deposition in lymphoid tissue, the CNS) and prion infectivity under varying conditions (e.g., chronic inflammation) and hosts (e.g., sheep, elk and deer, human): Chronic inflammation can alter the tropism of prion infectivity or PrPSc to organs hitherto believed prion free (e.g., liver, pancreas, kidney of mice, mammary gland of sheep, muscle of humans) (14-16). Moreover, PrPSc was reported in spleen and muscle tissue of sporadic Creutzfeldt-Jakob disease (sCJD) patients (17), and prion infectivity was demonstrated in muscle, blood, and saliva of deer suffering from CWD (18, 189). Also, prion infectivity was shown to be excreted via urine of prion-infected nephritic mice, a process defined as prionuria (19). These results emphasize the need for further assessment of possible public health risks from TSE-affected extraneural organs. It is very well possible that preexisting pathophysiological conditions of the infected host additionally contributed to unexpected distribution patterns of prion infectivity. For example, the presence of prion infectivity in the blood of sheep or deer may influence the deposition of prion infectivity in various organs previously deemed prion free. Therefore, it should be carefully reconsidered whether only organs of the CNS and the lymphoreticular system should be included in the current risk classifications of biologicals in the future. It will be important to test altered prion tropism profiles in nonlymphoid organs and body fluids (e.g., blood, urine, milk, saliva) of ruminants (e.g., sheep, goat, cattle, elk, and deer) and human patients suffering from sCJD and vCJD.


Recent in vivo evidence indicated that a similar phenomenon of conformational variants may occur in Alzheimer's disease (151). Here the existence of Aâ strains that can seed and accelerate aggregation and Aâ pathology was posited. These intriguing observations support the hypothesis that the pathogenetic mechanisms operating in Alzheimer's disease and in prion diseases have more in common than we often appreciate (152). Perhaps future studies will address whether different Aâ strains with distinct biochemical or neuropathological characteristics occur in humans. Can multiple prion strains coexist and effect prion replication? Two subtypes of sporadic CJD have recently been demonstrated to coexist in humans (62). Experimental studies have shown that when two strains infect the same host, one strain can impede the ability of the second strain to cause disease (153). Bartz and colleagues (154) recently suggested that this might be caused by the suppression of prion replication of the second strain. Strain features are useful for tracing prion infections between species. When transmitted to primates, BSE causes lesions strikingly similar to that of vCJD (155, 156). BSE is most likely transmissible to humans too, and strong circumstantial evidence (157-159) suggests that BSE is the cause of vCJD, which has claimed more than 200 lives in the United Kingdom (3, 160), as well as a much smaller number in some other countries (161).

NATURAL TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES: WHAT IS NEW? Cattle Prions More than a few surprises have come from further investigations of prion strains in field cases of TSEs. Until recently, BSE was believed to be associated with one single prion strain, classified by an exclusive and remarkably stable biochemical profile of PrPSc. However, distinct molecular signatures have recently been discovered through the large-scale screening of cattle mandated by European authorities in the context of BSE surveillance. These atypical profiles fall into either of two groups: H-type cases of protease-resistant fragments with a molecular weight higher than BSE, and bovine amyloidotic spongiform encephalopathy, or L type (lower) (162). To test whether these different biochemical and histopathological properties correspond to distinct strains, the Laude laboratory transmitted H-type-PrPSc isolates from French cattle into transgenic mice expressing bovine or ovine PrP (163). The recipient mice developed neurological signs exhibiting strain-specific features clearly distinct from that of the classical BSE agent, providing pivotal evidence that the underlying strains are distinct.

Atypical Sheep Scrapie In 1998, aberrant cases of sheep scrapie were described in Norway and the strain was newly classified as Nor98 (164). Active European Union surveillance later revealed additional cases of atypical scrapie in several other countries (165, 166). Sheep infected with Nor98, or atypical scrapie, accumulated PrPSc primarily in the cerebellum and cerebral cortex rather than in the brainstem target in the classical strain (167). Additionally, on western blot analysis of atypical scrapie cases, an additional small-molecular-weight (10-12 kDa) PrP fragment appeared afterPKdigestion and was shown by epitope mapping to lack both N and C termini of PrP (167, 168). Furthermore, atypical scrapie cases occurred not only in the classical scrapie-susceptible genotypes (A136 R154 Q171), but also in genotypes associated with high resistance to classical scrapie (A136 R154 R171) (165, 166). Were these atypical scrapie cases also infectious? In 2001, atypical scrapie cases were shown to be transmissible prion diseases after inoculated ovine PrP-expressing transgenic mice developed disease and prion aggregates (169). In the meantime, several countries appear to be reporting extremely high incidences of atypical scrapie, and in fact atypical scrapie appears to be the rule rather than the exception in some geographical areas.

Chronic Wasting Disease Among all animal prion diseases, CWD of cervids is likely the most efficiently transmitted. CWD infections occur in mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), Rocky Mountain elk (Cervus elaphus nelsoni) (170), and moose (Alces alces shirasi) (171). Prevalence can reach as high as 30% in dense, free-ranging deer populations and nearly 100% in captive animals (171). Hypotheses for CWD transmission range from spread via direct contact to exposure through grazing in areas contaminated by prion-infected secretions, excretions (saliva, urine, feces), tissues (placenta), or decomposed carcasses. Insightful experimental studies have recently revealed two key findings: (a) Saliva from CWD-infected deer can transmit disease (18), and (b) CWD-infected carcasses allowed to decay naturally in confined pastures can lead to CWD infections in captive deer (172). Additionally, the abundant CWD-prion accumulation within lymphoid tissues may also lead to CWD prion buildup in nonlymphoid organs with lymphoid follicles, as was recently shown in kidney, potentially shifting shedding routes (173). It is unknown whether other types of inflammation, such as the granulomatous inflammation in the intestine seen in Johne's disease (Mycobacterium avium subsp. paratuberculosis; affects ruminants, including deer and elk) or parasitic inflammation, could lead to or perhaps increase prion excretion by fecal routes. The environmental prion contamination in CWD underscores the difficulties of CWD disease management.Within North America,CWDinfected deer and elk have been detected in 14 states and two Canadian provinces (170, 174, 175). CWD surveillance in Europe has been more limited. However, in Germany, a total of 7300 captive and free-ranging cervids were tested forCWDwith no sign of infection (176). Reindeer or caribou (Rangifer tarandus), from North America or Northern Europe respectively, have a highly homologous prion sequence compared with mule deer and thus are likely susceptible to CWD. Other European cervids such as moose and red deer (C. elaphus) are also expected to be CWD susceptible. The deer and elk primary protein structures are highly conserved, as seen in other mammals. Interestingly, a polymorphism at codon 225S/F may influence CWD susceptibility in mule deer. When comparing the frequency of genotypes among CWDnegative and -positive deer (n = 1482), the odds that a CWD-infected animal was 225SS was 30 times greater when compared with 225SF, whereas the frequency of 225SF/FF genotypes in CWD-negative deer was 9.3%, but only 0.3% in CWD-positive deer (177).

Additionally, elk have a polymorphism at codon 132 (M/L) of Prnp, corresponding to polymorphic codon 129 (M/V) in humans. Elk expressing 132ML and 132LL Prnp were reported to be overrepresented among elk with CWD when compared with uninfected controls (178), and 132LL elk experimentally infected with CWD have resisted infection for at least four years, whereas 132MM or 132ML elk (n = 2 each) developed terminal clinical prion disease by 23 or 40 months post inoculation, respectively, confirmed by immunohistochemistry and western blotting for PrPSc (179). White-tailed deer also have Prnp polymorphisms that may affect their CWD susceptibility. A reduced susceptibility to CWD was linked to a G96S and a Q95H polymorphism in a study comparing allelic frequencies from CWD-positive and CWDnegative free-rangingWisconsin white-tailed deer (180).



Cross-sequence transmission of sporadic Creutzfeldt-Jakob disease creates a new prion strain

Date: August 25, 2007 at 12:42 pm PST


In this study, the strain-dependent traits of sCJDMM1 prions were inherited through cross-sequence transmission without any modification. The humanized mice with 129V/V produced type 1 PrPres after inoculation with sCJD-MM1 prions. Because sCJD-VV1 cases are extremely rare (at most 1-2% of the total number of sCJD cases) and characterized by early onset (mean age at onset: 39.3 years) (5),


our results raise the possibility that CJD cases classified as VV1 may include cases caused by iatrogenic transmission of sCJD-MM1 prions or food-borne infection by type 1 prions from animals, e.g., chronic wasting disease prions in cervid. In fact, two CJD-VV1 patients who hunted deer or consumed venison have been reported (40, 41). The results of the present study emphasize the need for traceback studies and careful re-examination of the biochemical properties of sCJD-VV1 prions.


In conclusion, cross-sequence transmission of sCJD-VV2 prions generates a new prion strain with altered conformational properties and disease phenotypes as p-dCJD prions. Furthermore, the newly generated prions have unique transmissibility including the traceback phenomenon. In the future, if atypical prion strains emerge through cross-sequence transmission, especially from animals, traceback studies will enable us to identify the origin of the prions.





Epidemiologic studies have also been initiated to identify human cases of prion disease among persons with an increased risk for exposure to potentially CWD-infected deer or elk meat (47). If such cases are identified, laboratory data showing similarities of the etiologic agent to that of the CWD agent would strengthen the conclusion for a causal link. Surveillance for human prion diseases, particularly in areas where CWD has been detected, remains important to effectively monitor the possible transmission of CWD to humans. Because of the long incubation period associated with prion diseases, convincing negative results from epidemiologic and experimental laboratory studies would likely require years of follow-up. In the meantime, to minimize the risk for exposure to the CWD agent, hunters should consult with their state wildlife agencies to identify areas where CWD occurs and continue to follow advice provided by public health and wildlife agencies. Hunters should avoid eating meat from deer and elk that look sick or test positive for CWD. They should wear gloves when field-dressing carcasses, bone-out the meat from the animal, and minimize handling of brain and spinal cord tissues. As a precaution, hunters should avoid eating deer and elk tissues known to harbor the CWD agent (e.g., brain, spinal cord, eyes, spleen, tonsils, lymph nodes) from areas where CWD has been identified.


From: TSS (216-119-163-189.ipset45.wt.net) Subject: CWD aka MAD DEER/ELK TO HUMANS ??? Date: September 30, 2002 at 7:06 am PST

From: "Belay, Ermias" To: Cc: "Race, Richard (NIH)" ; ; "Belay, Ermias" Sent: Monday, September 30, 2002 9:22 AM Subject: RE: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS

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----- From: 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] Subject: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS

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


A. Aguzzi - Chronic Wasting Disease (CWD) also needs to be addressed. Most serious because of rapid horizontal spread and higher prevalence than BSE in UK, up to 15% in some populations. Also may be a risk to humans - evidence that it is not dangerous to humans is thin.


The EMBO Journal, Vol. 19, No. 17 pp. 4425-4430, 2000 © European Molecular Biology Organization

Evidence of a molecular barrier limiting susceptibility of humans, cattle and sheep to chronic wasting disease

G.J. Raymond1, A. Bossers2, L.D. Raymond1, K.I. O?Rourke3, L.E. McHolland4, P.K. Bryant III4, M.W. Miller5, E.S. Williams6, M. Smits2 and B. Caughey1,7

1NIAID/NIH Rocky Mountain Laboratories, Hamilton, MT 59840, 3USDA/ARS/ADRU, Pullman, WA 99164-7030, 4USDA/ARS/ABADRL, Laramie, WY 82071, 5Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, CO 80526-2097, 6Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82070, USA and 2ID-Lelystad, Institute for Animal Science and Health, Lelystad, The Netherlands 7Corresponding author e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:bcaughey@nih.gov Received June 7, 2000; revised July 3, 2000; accepted July 5, 2000.


Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk, and little is known about its transmissibility to other species. An important factor controlling interspecies TSE susceptibility is prion protein (PrP) homology between the source and recipient species/genotypes. Furthermore, the efficiency with which the protease-resistant PrP (PrP-res) of one species induces the in vitro conversion of the normal PrP (PrP-sen) of another species to the protease-resistant state correlates with the cross-species transmissibility of TSE agents. Here we show that the CWD-associated PrP-res (PrPCWD) of cervids readily induces the conversion of recombinant cervid PrP-sen molecules to the protease-resistant state in accordance with the known transmissibility of CWD between cervids. In contrast, PrPCWD-induced conversions of human and bovine PrP-sen were much less efficient, and conversion of ovine PrP-sen was intermediate. These results demonstrate a barrier at the molecular level that should limit the susceptibility of these non-cervid species to CWD.


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.



Subject: DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability Date: Fri, 16 May 2003 11:47:37 -0500 From: "Terry S. Singeltary Sr." To: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000071/!x-usc:mailto:fdadockets@oc.fda.gov

Greetings FDA,

i would kindly like to comment on;

Docket 03D-0186

FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability

Several factors on this apparent voluntary proposal disturbs me greatly, please allow me to point them out;

1. MY first point is the failure of the partial ruminant-to-ruminant feed ban of 8/4/97. this partial and voluntary feed ban of some ruminant materials being fed back to cattle is terribly flawed. without the _total_ and _mandatory_ ban of all ruminant materials being fed back to ruminants including cattle, sheep, goat, deer, elk and mink, chickens, fish (all farmed animals for human/animal consumption), this half ass measure will fail terribly, as in the past decades...

2. WHAT about sub-clinical TSE in deer and elk? with the recent findings of deer fawns being infected with CWD, how many could possibly be sub-clinically infected. until we have a rapid TSE test to assure us that all deer/elk are free of disease (clinical and sub-clinical), we must ban not only documented CWD infected deer/elk, but healthy ones as well. it this is not done, they system will fail...

3. WE must ban not only CNS (SRMs specified risk materials), but ALL tissues. recent new and old findings support infectivity in the rump or ass muscle. wether it be low or high, accumulation will play a crucial role in TSEs.

4. THERE are and have been for some time many TSEs in the USA. TME in mink, Scrapie in Sheep and Goats, and unidentified TSE in USA cattle. all this has been proven, but the TSE in USA cattle has been totally ignored for decades. i will document this data below in my references.

5. UNTIL we ban all ruminant by-products from being fed back to ALL ruminants, until we rapid TSE test (not only deer/elk) but cattle in sufficient numbers to find (1 million rapid TSE test in USA cattle annually for 5 years), any partial measures such as the ones proposed while ignoring sub-clinical TSEs and not rapid TSE testing cattle, not closing down feed mills that continue to violate the FDA's BSE feed regulation (21 CFR 589.2000) and not making freely available those violations, will only continue to spread these TSE mad cow agents in the USA. I am curious what we will call a phenotype in a species that is mixed with who knows how many strains of scrapie, who knows what strain or how many strains of TSE in USA cattle, and the CWD in deer and elk (no telling how many strains there), but all of this has been rendered for animal feeds in the USA for decades. it will get interesting once someone starts looking in all species, including humans here in the USA, but this has yet to happen...

6. IT is paramount that CJD be made reportable in every state (especially ''sporadic'' cjd), and that a CJD Questionnaire must be issued to every family of a victim of TSE. only checking death certificates will not be sufficient. this has been proven as well (see below HISTORY OF CJD -- CJD QUESTIONNAIRE)

7. WE must learn from our past mistakes, not continue to make the same mistakes...


please see full text submission


submission documented here ;

2003D-0186 Guidance for Industry: Use of Material From Deer and Elk In Animal Feed

EMC 1 Terry S. Singeltary Sr. Vol #: 1


Thursday, August 28, 2008

cwd, feeding, and baiting piles


Content-Type: text/html FURTHER into this case study, Colorado Surveillance Program for Chronic Wasting Disease Transmission to Humans (TWO SUSPECT CASES) a look at case 1 and case 2 ;


A 52-year-old right-handed woman presented with a 1-year history of progressive memory loss, language impairment, visuospatial disturbance, and myoclonus. She related that she had been a histology technician in a laboratory that processed tissue specimens from deer and elk with CWD and had handled specimens without wearing gloves. Both she and her family expressed significant concerns about the possibility of transdermal transmission of CWD. Her family history was negative for dementia and other neurologic disorders. Brain magnetic resonance imaging showed mild diffuse volume loss, and electroencephalography demonstrated mild diffuse slowing. Other laboratory studies were unremarkable. Cerebrospinal fluid findings were unremarkable except for a weakly immunostaining 14-3-3 protein band, an indeterminate finding for the diagnosis of prion disease. Genetic testing of the prion protein gene was normal, revealing methionine homozygosity at codon 129. Brain biopsy results were negative for the presence of proteaseresistant prion protein but showed definite Alzheimer disease with numerous neuritic plaques and tau-positive neurofibrillary tangles (Figure). Further analysis of brain tissue at the National Prion Disease Pathology Surveillance Center was negative for prion disease by Western blot analysis. Subsequent investigation by the state department of health revealed the patient had worked in an area of the laboratory that conducted necropsies on domestic animals and had never been assigned to the CWD testing laboratory. The Colorado Department of Public Health and Environment could not confirm that the technician had ever worked with deer and elk tissues.


This 25-year-old right-handed man had a 4-month history of progressive gait disturbance, myoclonus, hallucinations, slowed cognition, impaired attention, and memory loss. He had hunted deer and elk in a CWD endemic area of southern Wyoming and cooked and ate the field-dressed meat. His family history was significant in that his mother had died of a dementing disease at age 40 years, although there was neither a clinical diagnosis nor an autopsy. Brain magnetic resonance imaging findings were unremarkable, and electroencephalography demonstrated 1-Hz high-amplitude periodic sharp wave complexes. Other laboratory studies had negative results. Testing for the 14-3-3 protein had positive results, but the cerebrospinal fluid was otherwise unremarkable. The diagnosis of Gerstmann-Stra¨ussler-Scheinker syndrome, a familial prion disease, was confirmed with a detailed autopsy examination and referral of the brain to the National Prion Disease Pathology Surveillance Center. Autopsy brain tissue showed the presence of proteaseresistant prion protein by Western blot analysis. Genetic evaluation revealed the P102L mutation in the prion protein gene with methionine/valine heterozygosity at codon 129.


I can't understand how they can keep claiming 'low, or no occupational transmission of CJD' ??? when there have been many cases that should have raised awareness, and in some cases they did, only to be swept under the rug as the infamous sporadic CJD, or some other TSE other than the nvCJD of the ukbsenvcjd only theory. it's a blown theory no one will accept too. lets look at a few occupational cases. ...TSS

now, some things to ponder ;


1. Do neuritic plaques and tau-positive neurofibrillary tangles indicate definite AD? Aren't these also found in GSS? What about concurrent AD and TSE?

2. Are the NPDPSC results conclusive? Do WB results depend on the part of the brain sampled?

3. Doesn't it seem unlikely the woman would flat-out lie about working with CWD tissues? (I'm working on this locally.)

4. What about cross-contamination? The lab gets large numbers of scrapie-infected sheep and CWD-infected deer and elk. I assume the necropsy area is contaminated with TSEs.

Re: Colorado Surveillance Program for Chronic Wasting Disease Transmission to Humans (TWO SUSPECT CASES)


Thursday, April 03, 2008

A prion disease of cervids: Chronic wasting disease

2008 1: Vet Res. 2008 Apr 3;39(4):41

A prion disease of cervids: Chronic wasting disease

Sigurdson CJ.


*** twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center***,


full text ;


Tuesday, August 12, 2008

Biosafety in Microbiological and Biomedical Laboratories Fifth Edition 2007 (occupational exposure to prion diseases)


Tuesday, August 26, 2008

Alzheimer's Transmission of AA-amyloidosis: Similarities with Prion Disorders NEUROPRION 2007


10 people killed by new CJD-like disease

Public release date: 9-Jul-2008

Since Gambetti's team wrote a paper describing an initial 11 cases referred to his centre between 2002 and 2006 (Annals of Neurology, vol 63, p 697), another five have come to light. "So it is possible that it could be just the tip of the iceberg," Gambetti says

Thursday, July 10, 2008 A New Prionopathy


Sunday, August 10, 2008

A New Prionopathy OR more of the same old BSe and sporadic CJD


Sunday, August 24, 2008

Sporadic Fatal Insomnia with Unusual Biochemical and Neuropathological Findings


Rancid Crabtree wrote ;

Our Technical advisory team consisted of Research Scientists, Biologists, DNR personnel and many other folks involved with the disease.

NO victims group on the Technical advisory committee ? what do we know...TSS

Communicated by: Terry S. Singeltary Sr.

[In submitting these data, Terry S. Singeltary Sr. draws attention to the steady increase in the "type unknown" category, which, according to their definition, comprises cases in which vCJD could be excluded. The total of 26 cases for the current year (2007) is disturbing, possibly symptomatic of the circulation of novel agents. Characterization of these agents should be given a high priority. - Mod.CP]



There is a growing number of human CJD cases, and they were presented last week in San Francisco by Luigi Gambatti(?) from his CJD surveillance collection.

He estimates that it may be up to 14 or 15 persons which display selectively SPRPSC and practically no detected RPRPSC proteins.




MARCH 26, 2003

RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob

disease in the United States

Email Terry S. Singeltary:


I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to comment on the CDC's attempts to monitor the occurrence of emerging forms of CJD. Asante, Collinge et al [1] have reported that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest sporadic CJD. However, CJD and all human TSEs are not reportable nationally. CJD and all human TSEs must be made reportable in every state and internationally. I hope that the CDC does not continue to expect us to still believe that the 85%+ of all CJD cases which are sporadic are all spontaneous, without route/source. We have many TSEs in the USA in both animal and man. CWD in deer/elk is spreading rapidly and CWD does transmit to mink, ferret, cattle, and squirrel monkey by intracerebral inoculation. With the known incubation periods in other TSEs, oral transmission studies of CWD may take much longer. Every victim/family of CJD/TSEs should be asked about route and source of this agent. To prolong this will only spread the agent and needlessly expose others. In light of the findings of Asante and Collinge et al, there should be drastic measures to safeguard the medical and surgical arena from sporadic CJDs and all human TSEs. I only ponder how many sporadic CJDs in the USA are type 2 PrPSc?



Hardcover, 304 pages plus photos and illustrations. ISBN 0-387-95508-9

June 2003

BY Philip Yam


Answering critics like Terry Singeltary, who feels that the U.S. under- counts CJD, Schonberger conceded that the current surveillance system has errors but stated that most of the errors will be confined to the older population.


Diagnosis and Reporting of Creutzfeldt-Jakob Disease Singeltary, Sr et al. JAMA.2001; 285: 733-734. Vol. 285 No. 6, February 14, 2001 JAMA

Diagnosis and Reporting of Creutzfeldt-Jakob Disease

To the Editor: In their Research Letter, Dr Gibbons and colleagues1 reported that the annual US death rate due to Creutzfeldt-Jakob disease (CJD) has been stable since 1985. These estimates, however, are based only on reported cases, and do not include misdiagnosed or preclinical cases. It seems to me that misdiagnosis alone would drastically change these figures. An unknown number of persons with a diagnosis of Alzheimer disease in fact may have CJD, although only a small number of these patients receive the postmortem examination necessary to make this diagnosis. Furthermore, only a few states have made CJD reportable. Human and animal transmissible spongiform encephalopathies should be reportable nationwide and internationally.

Terry S. Singeltary, Sr Bacliff, Tex

1. Gibbons RV, Holman RC, Belay ED, Schonberger LB. Creutzfeldt-Jakob disease in the United States: 1979-1998. JAMA. 2000;284:2322-2323. FREE FULL TEXT



2 January 2000

British Medical Journal U.S. Scientist should be concerned with a CJD epidemic in the U.S., as well


15 November 1999

British Medical Journal vCJD in the USA * BSE in U.S.







The statistical incidence of CJD cases in the United States has been revised to reflect that there is one case per 9000 in adults age 55 and older. Eighty-five percent of the cases are sporadic, meaning there is no known cause at present.





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