Chronic Wasting Disease CWD in cervidae and transmission to other species
> but the U.S. Centers for Disease Control and Prevention has said there is no evidence the illness can be transmitted to humans or livestock.
that statement is a red herring, or simply not completely true, take your pick, depending what you consider as evidence.
let’s evaluate this, shall we, and you be the judge...
UPDATED CORRESPONDENCE FROM AUTHORS OF THIS STUDY I.E. COLBY, PRUSINER ET AL, ABOUT MY CONCERNS OF THE DISCREPANCY BETWEEN THEIR FIGURES AND MY FIGURES OF THE STUDIES ON CWD TRANSMISSION TO CATTLE ;
CWD to cattle figures CORRECTION
I believe the statement and quote below is incorrect ;
"CWD has been transmitted to cattle after intracerebral inoculation, although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). This finding raised concerns that CWD prions might be transmitted to cattle grazing in contaminated pastures."
Please see ;
Within 26 months post inoculation, 12 inoculated animals had lost weight, revealed abnormal clinical signs, and were euthanatized. Laboratory tests revealed the presence of a unique pattern of the disease agent in tissues of these animals. These findings demonstrate that when CWD is directly inoculated into the brain of cattle, 86% of inoculated cattle develop clinical signs of the disease.
" although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). "
shouldn't this be corrected, 86% is NOT a low rate. ...
Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA 77518
Thanks so much for your updates/comments. We intend to publish as rapidly as possible all updates/comments that contribute substantially to the topic under discussion.
re-Prions David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations
1Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143 2Department of Neurology, University of California, San Francisco, San Francisco, California 94143 Correspondence: firstname.lastname@example.org
Mule deer, white-tailed deer, and elk have been reported to develop CWD. As the only prion disease identified in free-ranging animals, CWD appears to be far more communicable than other forms of prion disease. CWD was first described in 1967 and was reported to be a spongiform encephalopathy in 1978 on the basis of histopathology of the brain. Originally detected in the American West, CWD has spread across much of North America and has been reported also in South Korea. In captive populations, up to 90% of mule deer have been reported to be positive for prions (Williams and Young 1980). The incidence of CWD in cervids living in the wild has been estimated to be as high as 15% (Miller et al. 2000). The development of transgenic (Tg) mice expressing cervid PrP, and thus susceptible to CWD, has enhanced detection of CWD and the estimation of prion titers (Browning et al. 2004; Tamgüney et al. 2006). Shedding of prions in the feces, even in presymptomatic deer, has been identified as a likely source of infection for these grazing animals (Williams and Miller 2002; Tamgüney et al. 2009b). CWD has been transmitted to cattle after intracerebral inoculation, although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). This finding raised concerns that CWD prions might be transmitted to cattle grazing in contaminated pastures.
----- Original Message -----
From: David Colby To: email@example.com
Sent: Tuesday, March 01, 2011 8:25 AM
Subject: Re: FW: re-Prions David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations
Dear Terry Singeltary,
Thank you for your correspondence regarding the review article Stanley Prusiner and I recently wrote for Cold Spring Harbor Perspectives. Dr. Prusiner asked that I reply to your message due to his busy schedule. We agree that the transmission of CWD prions to beef livestock would be a troubling development and assessing that risk is important. In our article, we cite a peer-reviewed publication reporting confirmed cases of laboratory transmission based on stringent criteria. The less stringent criteria for transmission described in the abstract you refer to lead to the discrepancy between your numbers and ours and thus the interpretation of the transmission rate. We stand by our assessment of the literature--namely that the transmission rate of CWD to bovines appears relatively low, but we recognize that even a low transmission rate could have important implications for public health and we thank you for bringing attention to this matter. Warm Regards, David Colby -- David Colby, PhDAssistant Professor Department of Chemical Engineering University of Delaware
SNIP...SEE FULL TEXT ;
UPDATED DATA ON 2ND CWD STRAIN Wednesday, September 08, 2010 CWD PRION CONGRESS SEPTEMBER 8-11 2010
Sunday, August 19, 2012
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation 2012
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research Unit
PO-081: Chronic wasting disease in the cat— Similarities to feline spongiform encephalopathy (FSE)
PO-081: Chronic wasting disease in the cat— Similarities to feline spongiform encephalopathy (FSE)
Thursday, May 31, 2012
CHRONIC WASTING DISEASE CWD PRION2012 Aerosol, Inhalation transmission, Scrapie, cats, species barrier, burial, and more
CHRONIC WASTING DISEASE, CWD, AND THE DEER PENS AT THE FOOT HILLS CAMPUS
*** Spraker suggested an interesting explanation for the occurrence of CWD. The deer pens at the Foot Hills Campus were built some 30-40 years ago by a Dr. Bob Davis. At or about that time, allegedly, some scrapie work was conducted at this site. When deer were introduced to the pens they occupied ground that had previously been occupied by sheep.
(PLEASE NOTE SOME OF THESE OLD UK GOVERNMENT FILE URLS ARE SLOW TO OPEN, AND SOMETIMES YOU MAY HAVE TO CLICK ON MULTIPLE TIMES, PLEASE BE PATIENT, ANY PROBLEMS PLEASE WRITE ME PRIVATELY, AND I WILL TRY AND FIX OR SEND YOU OLD PDF FILE...TSS)
PERCEPTIONS OF UNCONVENTIONAL SLOW VIRUS DISEASES OF ANIMALS IN USA
REPORT OF A VISIT TO THE USA APRIL-MAY 1989
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.
2011 Annual Report
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research Unit
2011 Annual Report
In Objective 1, Assess cross-species transmissibility of transmissible spongiform encephalopathies (TSEs) in livestock and wildlife, numerous experiments assessing the susceptibility of various TSEs in different host species were conducted. Most notable is deer inoculated with scrapie, which exhibits similarities to chronic wasting disease (CWD) in deer suggestive of sheep scrapie as an origin of CWD.
4.Accomplishments 1. Deer inoculated with domestic isolates of sheep scrapie. Scrapie-affected deer exhibit 2 different patterns of disease associated prion protein. In some regions of the brain the pattern is much like that observed for scrapie, while in others it is more like chronic wasting disease (CWD), the transmissible spongiform encephalopathy typically associated with deer. This work conducted by ARS scientists at the National Animal Disease Center, Ames, IA suggests that an interspecies transmission of sheep scrapie to deer may have been the origin of CWD. This is important for husbandry practices with both captive deer, elk and sheep for farmers and ranchers attempting to keep their herds and flocks free of CWD and scrapie.
now, years later, see the latest studies here on scrapie and cwd ;
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer
Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA
Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. The purpose of these experiments was to determine susceptibility of white-tailed deer (WTD) to scrapie and to compare the resultant clinical signs, lesions, and molecular profiles of PrPSc to those of chronic wasting disease (CWD). We inoculated WTD intracranially (IC; n = 5) and by a natural route of exposure (concurrent oral and intranasal (IN); n = 5) with a US scrapie isolate. All deer were inoculated with a 10% (wt/vol) brain homogenate from sheep with scrapie (1ml IC, 1 ml IN, 30 ml oral). All deer inoculated by the intracranial route had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues as early as 7 months-post-inoculation (PI) and a single deer that was necropsied at 15.6 months had widespread distribution of PrPSc highlighting that PrPSc is widely distributed in the CNS and lymphoid tissues prior to the onset of clinical signs. IC inoculated deer necropsied after 20 months PI (3/5) had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in WTD after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile similar to CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like. After a natural route of exposure, 100% of WTD were susceptible to scrapie. Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer exhibited two different molecular profiles: samples from obex resembled CWD whereas those from cerebrum were similar to the original scrapie inoculum. On further examination by WB using a panel of antibodies, the tissues from deer with scrapie exhibit properties differing from tissues either from sheep with scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are strongly immunoreactive when probed with mAb P4, however, samples from WTD with scrapie are only weakly immunoreactive. In contrast, when probed with mAb’s 6H4 or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly immunoreactive and samples from WTD with scrapie are strongly positive. This work demonstrates that WTD are highly susceptible to sheep scrapie, but on first passage, scrapie in WTD is differentiable from CWD.
White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection
Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS
Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. Previous experiments demonstrated that white-tailed deer are susceptible to sheep-derived scrapie by intracranial inoculation. The purpose of this study was to determine susceptibility of white-tailed deer to scrapie after a natural route of exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal (1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with scrapie. Non-inoculated deer were maintained as negative controls. All deer were observed daily for clinical signs. Deer were euthanized and necropsied when neurologic disease was evident, and tissues were examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and western blot (WB). One animal was euthanized 15 months post-inoculation (MPI) due to an injury. At that time, examination of obex and lymphoid tissues by IHC was positive, but WB of obex and colliculus were negative. Remaining deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by potential natural routes of inoculation. In-depth analysis of tissues will be done to determine similarities between scrapie in deer after intracranial and oral/intranasal inoculation and chronic wasting disease resulting from similar routes of inoculation.
see full text ;
Envt.11: Swine Are Susceptible to Chronic Wasting Disease by Intracerebral Inoculation
Justin Greenlee,† Robert Kunkle and Jodi Smith National Animal Disease Center, ARS, USDA; Ames, IA USA †Presenting author; Email: firstname.lastname@example.org
Transmissible spongiform encephalopathies (TSEs, prion diseases) are chronic neurodegenerative diseases that occur in humans, cattle, sheep, goats, cervids and a number of laboratory animal models. There is no evidence of the natural occurrence of any form of TSE in the pig, but pigs have been shown to be susceptible to Bovine Spongiform Encephalopathy (BSE) infection by multiple-route parenteral challenge. However, pigs orally exposed at eight weeks of age to large amounts of brain from cattle clinically affected with BSE did not support infection after seven years of observation. In the US, feeding of ruminant by-products to ruminants is prohibited, but feeding of ruminant materials to swine, mink and poultry still occurs. Although unlikely, the potential for swine to have access to TSE-contaminated feedstuffs exists. The potential for swine to serve as a host for the agent of chronic wasting disease (CWD) is unknown. The purpose of this study was to perform intracerebral inoculation of the CWD agent to determine the potential of swine as a host for the CWD agent and their clinical susceptibility. This study utilized 26 swine randomly divided into controls (n = 6) and intracranial inoculates (n = 20). CWD inoculum was a pooled 10% (w/v) homogenate derived from three white-tailed deer clinically ill with CWD from three different sources (elk, white-tailed deer, mule deer) and was given by a single intracranial injection of 0.75 ml. Necropsies were done on ten animals at six months post inoculation (PI), at approximately the time the pigs were expected to reach market weight. Additional pigs have been necropsied due to intercurrent disease (primarily lameness) over the course of the study (29–64 months). Samples collected at necropsy were examined for spongiform change after routine staining (hematoxylin and eosin) and for immunoreactivity to prion protein (PrPSc) by immunohistochemistry. Further, brain samples from at least two regions were tested by western blot. No results suggestive of spongiform encephalopathy were obtained from animals necropsied at six months PI, but positive results after an incubation period of only six months would be uncharacteristic. A single animal was positive for CWD by IHC and WB at 64 months PI. Two inoculated pigs and one control pig remain alive, so it is not possible to determine the attack rate of CWD in swine at this time. However, lack of positive results in pigs necropsied at 29–56 months PI and the long incubation of the single positive case suggest that swine are unlikely to be affected by CWD if inoculated by a natural route.
Chronic Wasting Disease Susceptibility of Four North American Rodents
Chad J. Johnson1*, Jay R. Schneider2, Christopher J. Johnson2, Natalie A. Mickelsen2, Julia A. Langenberg3, Philip N. Bochsler4, Delwyn P. Keane4, Daniel J. Barr4, and Dennis M. Heisey2 1University of Wisconsin School of Veterinary Medicine, Department of Comparative Biosciences, 1656 Linden Drive, Madison WI 53706, USA 2US Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison WI 53711, USA 3Wisconsin Department of Natural Resources, 101 South Webster Street, Madison WI 53703, USA 4Wisconsin Veterinary Diagnostic Lab, 445 Easterday Lane, Madison WI 53706, USA *Corresponding author email: email@example.com
We intracerebrally challenged four species of native North American rodents that inhabit locations undergoing cervid chronic wasting disease (CWD) epidemics. The species were: deer mice (Peromyscus maniculatus), white-footed mice (P. leucopus), meadow voles (Microtus pennsylvanicus), and red-backed voles (Myodes gapperi). The inocula were prepared from the brains of hunter-harvested white-tailed deer from Wisconsin that tested positive for CWD. Meadow voles proved to be most susceptible, with a median incubation period of 272 days. Immunoblotting and immunohistochemistry confirmed the presence of PrPd in the brains of all challenged meadow voles. Subsequent passages in meadow voles lead to a significant reduction in incubation period. The disease progression in red-backed voles, which are very closely related to the European bank vole (M. glareolus) which have been demonstrated to be sensitive to a number of TSEs, was slower than in meadow voles with a median incubation period of 351 days. We sequenced the meadow vole and red-backed vole Prnp genes and found three amino acid (AA) differences outside of the signal and GPI anchor sequences. Of these differences (T56-, G90S, S170N; read-backed vole:meadow vole), S170N is particularly intriguing due its postulated involvement in "rigid loop" structure and CWD susceptibility. Deer mice did not exhibit disease signs until nearly 1.5 years post-inoculation, but appear to be exhibiting a high degree of disease penetrance. White-footed mice have an even longer incubation period but are also showing high penetrance. Second passage experiments show significant shortening of incubation periods. Meadow voles in particular appear to be interesting lab models for CWD. These rodents scavenge carrion, and are an important food source for many predator species. Furthermore, these rodents enter human and domestic livestock food chains by accidental inclusion in grain and forage. Further investigation of these species as potential hosts, bridge species, and reservoirs of CWD is required.
please see ;
Title: Transmission of chronic wasting disease of mule deer to Suffolk sheep following intracerebral inoculation
Hamir, Amirali Kunkle, Robert Cutlip, Randall - ARS RETIRED Miller, Janice - ARS RETIRED Williams, Elizabeth - UNIV OF WYOMING, LARAMIE Richt, Juergen
Submitted to: Journal of Veterinary Diagnostic Investigation Publication Type: Peer Reviewed Journal Publication Acceptance Date: June 20, 2006 Publication Date: November 1, 2006 Citation: Hamir, A.N., Kunkle, R.A., Cutlip, R.C., Miller, J.M., Williams, E.S., Richt, J.A. 2006. Transmission of chronic wasting disease of mule deer to Suffolk sheep following intracerebral inoculation. Journal of Veterinary Diagnostic Investigation. 18(6):558-565.
Interpretive Summary: Chronic wasting disease (CWD) has been identified in captive and free ranging deer and elk since 1967. To determine the transmissibility of CWD to sheep and to provide information about the disease and tests for detection of CWD in sheep, 8 lambs were inoculated with brain suspension from mule deer naturally affected with CWD. Two other lambs were kept as controls. Only 1 sheep developed clinical disease at 35 months after inoculation. The study was terminated at 72 months after the inoculation. At that time one other sheep was found to be positive for the disease. It is proposed that the host's genetic makeup may play a role in transmission of the disease to domestic sheep. Impact. This is the first study which shows that it is possible to transmit CWD to a small number of sheep. Technical Abstract: Chronic wasting disease (CWD) has been identified in captive and free-ranging cervids since 1967. To determine the transmissibility of CWD to sheep and to provide information about clinical course, lesions, and suitability of currently used diagnostic procedures for detection of CWD in sheep, 8 Suffolk lambs (4 QQ and 4 QR at codon 171 of prion protein (PRNP) gene) were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD (CWD**md). Two other lambs (1 QQ and 1 QR at codon 171 of PRNP gene) were kept as non-inoculated controls. Within 36 months post inoculation (MPI), 2 animals became recumbent and were euthanized. However, only 1 sheep (euthanized at 35 MPI) had shown clinical signs that were consistent with those of scrapie. Microscopic lesions of spongiform encephalopathy (SE) were seen in this sheep and its tissues were positive for the abnormal prion protein (PrPres) by immunohistochemistry and Western blot. Retrospective examination of the PRNP genotype of this animal revealed that it was heterozygous (AV) at codon 136. In the next 24 months, 3 other sheep were euthanized because of conditions unrelated to TSE. The remaining 3 sheep remained non-clinical at the termination of the study (72 MPI) and were euthanized at that time. One of these 3 revealed SE and its tissues were positive for PrPres. These findings demonstrate that it is possible to transmit CWD**md agent to sheep via the intracerebral route. However, the host genotype may play a significant part in successful transmission and incubation period of this agent.
Chronic wasting disease: Fingerprinting the culprit in risk assessments
Volume 6, Issue 1 January/February/March 2012 Pages 17 - 22 http://dx.doi.org/10.4161/pri.6.1.17776
Keywords: Fourier transform-infrared (FT-IR) spectroscopy, chronic wasting disease (CWD), prion, prion protein (PrP), prion typing, protein misfolding cyclic amplification (PMCA), risk assessment, seeding activity, strains, transmissible spongiform encephalopathies (TSE)
Authors: Martin L. Daus and Michael Beekes View affiliations Hide affiliations Martin L. Daus
P24 -Transmissible Spongiform Encephalopathies; Robert Koch-Institut; Berlin, Germany Michael Beekes Corresponding author: BeekesM@rki.de P24 -Transmissible Spongiform Encephalopathies; Robert Koch-Institut; Berlin, Germany
Abstract: Transmissible spongiform encephalopathies (prion diseases) in animals may be associated with a zoonotic risk potential for humans as shown by the occurrence of variant Creutzfeldt-Jakob disease in the wake of the bovine spongiform encephalopathy epidemic. Thus, the increasing exposure of humans in North America to cervid prions of chronic wasting disease (CWD) in elk and deer has prompted comprehensive risk assessments. The susceptibility of humans to CWD infections is currently under investigation in different studies using macaques as primate models. The necessity for such studies was recently reinforced when disease-associated prion protein and its seeding activity were detected in muscles of clinically inconspicuous CWD-infected white-tailed deer (WTD). Increasing evidence points to the existence of different CWD strains, and CWD prions may also change or newly emerge over time. Therefore, CWD isolates examined in macaques should be characterized as precisely as possible for their molecular identity. On this basis other CWD field samples collected in the past, present or future could be systematically compared with macaque-tested inocula in order to assess whether they are covered by the ongoing risk assessments in primates. CWD typing by Fourier transform-infrared spectroscopy of pathological prion protein may provide a method of choice for this purpose.
Exposure of humans to CWD prions
Chronic wasting disease is a TSE in white-tailed deer, mule deer, Rocky Mountain elk and moose. Over the past years this disease has shown a sustained spread in captive as well as free-ranging cervids in North America.6,7 The increasingly frequent and widespread 5 occurrence of affected animals is likely to augment the exposure of humans to the CWD agent. Prion infectivity or TSE-associated prion protein have been detected in the central and peripheral nervous system, in a variety of lymphoid tissues as well as in heart muscle, blood, saliva, feces and urine of CWD-infected cervids7. Also, infectious CWD agent was found in antler velvet of elk and in skeletal muscles of mule deer with chronic wasting disease.8,9 Thus, particularly persons processing cervid carcasses, users of medicinal products made from antler velvet and consumers of venison may be exposed to an elevated risk for contamination with CWD prions.
Recently, PrPTSE and its proteinaceous seeding activity could be directly demonstrated, for the first time, in skeletal muscles of CWD-infected cervids.10 The animals examined in this study were farmed and free-ranging WTD for which no clinical signs of CWD had been recognized. However, they had been officially confirmed positive for CWD based on the detection of PrPTSE in brain tissue or lymph nodes and were thus apparently in a state of pre or subclinical infection. Muscles from such clinically inconspicuous carrier animals appear more likely to enter the human food chain than meat from cervids that show symptoms of CWD. Whether this may provide a relevant mode for the inadvertent foodborne transmission of CWD prions is still unclear. Yet, the presence and seeding activity of PrPTSE in skeletal muscles of pre- or subclinically infected WTD reinforced the need to comprehensively assess whether humans are susceptible to zoonotic CWD infections.
Transmissibility to humans
The current state of epidemiological research suggests a rather robust barrier for the transmission of CWD to humans. Particularly, the surveillance of human prion diseases in areas with a long history of endemic CWD such as Colorado and Wyoming did not reveal evidence for zoonotic transmissions of the disease to cervid hunters or consumers of meat from elk and deer.6,11 However, as discussed by Belay et al.,6 the intensity of human exposure to CWD prions may increase due to a further spread and rising prevalence of the disease in cervids. Therefore, and with the generally long latency periods of human prion diseases in mind, previous epidemiological findings cannot be readily extrapolated. Until recently, experimental studies that pursued biochemical approaches or used transgenic mice to ascertain the susceptibility of humans to CWD infections consistently seemed to corroborate current epidemiological findings: CWD-infected cervid brain tissue did not seed the conversion of PrPC 133 into PrPres in PMCA assays using brain homogenate from macaques or transgenic mice expressing human PrPC as test substrate12 , and transgenic mice overexpressing human PrPC were resistant to infection after intracerebral challenge with CWD prions from mule deer.13 However, a study published by Barria et al.14 in March 2011 found that cervid PrPTSE can seed the conversion of human PrPC into PrPres by PMCA when the CWD agent has been previously passaged in vitro or in vivo. Specifically, this was demonstrated for CWD prions from naturally affected mule deer either passaged by serial PMCA using deer PrPC as conversion substrate or in transgenic mice expressing cervid PrPC. The authors of this study pointed out that CWD prions may undergo a gradual process of change and adaptation via successive passages in the cervid population. They concluded that the reported findings, if corroborated by infectivity assays, may imply “that CWD prions have the potential to infect humans and that this ability progressively increases with CWD spreading”.
Volume 18, Number 3—March 2012
Samuel E. Saunders1, Shannon L. Bartelt-Hunt, and Jason C. Bartz
Author affiliations: University of Nebraska-Lincoln, Omaha, Nebraska, USA (S.E. Saunders, S.L. Bartelt-Hunt); Creighton University, Omaha (J.C. Bartz)
Occurrence, Transmission, and Zoonotic Potential of Chronic Wasting Disease
Most epidemiologic studies and experimental work have suggested that the potential for CWD transmission to humans is low, and such transmission has not been documented through ongoing surveillance (2,3). In vitro prion replication assays report a relatively low efficiency of CWD PrPSc-directed conversion of human PrPc to PrPSc (30), and transgenic mice overexpressing human PrPc are resistant to CWD infection (31); these findings indicate low zoonotic potential. However, squirrel monkeys are susceptible to CWD by intracerebral and oral inoculation (32). Cynomolgus macaques, which are evolutionarily closer to humans than squirrel monkeys, are resistant to CWD infection (32). Regardless, the finding that a primate is orally susceptible to CWD is of concern.
Intraspecies and interspecies passage of the CWD agent may also increase the risk for zoonotic CWD transmission. The CWD prion agent is undergoing serial passage naturally as the disease continues to emerge. In vitro and in vivo intraspecies transmission of the CWD agent yields PrPSc with an increased capacity to convert human PrPc to PrPSc (30). Interspecies prion transmission can alter CWD host range (38) and yield multiple novel prion strains (3,28). The potential for interspecies CWD transmission (by cohabitating mammals) will only increase as the disease spreads and CWD prions continue to be shed into the environment. This environmental passage itself may alter CWD prions or exert selective pressures on CWD strain mixtures by interactions with soil, which are known to vary with prion strain (25), or exposure to environmental or gut degradation.
Given that prion disease in humans can be difficult to diagnose and the asymptomatic incubation period can last decades, continued research, epidemiologic surveillance, and caution in handling risky material remain prudent as CWD continues to spread and the opportunity for interspecies transmission increases. Otherwise, similar to what occurred in the United Kingdom after detection of variant CJD and its subsequent link to BSE, years of prevention could be lost if zoonotic transmission of CWD is subsequently identified,...
full text ;
Zoonotic Potential of CWD: Experimental Transmissions to Non-Human Primates
Emmanuel Comoy,1,† Valérie Durand,1 Evelyne Correia,1 Aru Balachandran,2 Jürgen Richt,3 Vincent Beringue,4 Juan-Maria Torres,5 Paul Brown,1 Bob Hills6 and Jean-Philippe Deslys1
1Atomic Energy Commission; Fontenay-aux-Roses, France; 2Canadian Food Inspection Agency; Ottawa, ON Canada; 3Kansas State University; Manhattan, KS USA; 4INRA; Jouy-en-Josas, France; 5INIA; Madrid, Spain; 6Health Canada; Ottawa, ON Canada
†Presenting author; Email: firstname.lastname@example.org
The constant increase of chronic wasting disease (CWD) incidence in North America raises a question about their zoonotic potential. A recent publication showed their transmissibility to new-world monkeys, but no transmission to old-world monkeys, which are phylogenetically closer to humans, has so far been reported. Moreover, several studies have failed to transmit CWD to transgenic mice overexpressing human PrP. Bovine spongiform encephalopathy (BSE) is the only animal prion disease for which a zoonotic potential has been proven. We described the transmission of the atypical BSE-L strain of BSE to cynomolgus monkeys, suggesting a weak cattle-to-primate species barrier. We observed the same phenomenon with a cattleadapted strain of TME (Transmissible Mink Encephalopathy). Since cattle experimentally exposed to CWD strains have also developed spongiform encephalopathies, we inoculated brain tissue from CWD-infected cattle to three cynomolgus macaques as well as to transgenic mice overexpressing bovine or human PrP. Since CWD prion strains are highly lymphotropic, suggesting an adaptation of these agents after peripheral exposure, a parallel set of four monkeys was inoculated with CWD-infected cervid brains using the oral route. Nearly four years post-exposure, monkeys exposed to CWD-related prion strains remain asymptomatic. In contrast, bovinized and humanized transgenic mice showed signs of infection, suggesting that CWD-related prion strains may be capable of crossing the cattle-to-primate species barrier. Comparisons with transmission results and incubation periods obtained after exposure to other cattle prion strains (c-BSE, BSE-L, BSE-H and cattle-adapted TME) will also be presented, in order to evaluate the respective risks of each strain.
Pathological Prion Protein (PrPTSE) in Skeletal Muscles of Farmed and Free Ranging White-Tailed Deer Infected with Chronic Wasting Disease
Martin L. Daus,1,† Johanna Breyer,2 Katjs Wagenfuehr,1 Wiebke Wemheuer,2 Achim Thomzig,1 Walter Schulz-Schaeffer2 and Michael Beekes1 1Robert Koch Institut; P24 TSE; Berlin, Germany; 2Department of Neuropathology, Prion and Dementia Research Unit, University Medical Center Göttingen; Göttingen, Germany
†Presenting author; Email: email@example.com
Chronic wasting disease (CWD) is a contagious, rapidly spreading transmissible spongiform encephalopathy (TSE) occurring in cervids in North America. Despite efficient horizontal transmission of CWD among cervids natural transmission of the disease to other species has not yet been observed. Here, we report a direct biochemical demonstration of pathological prion protein PrPTSE and of PrPTSE-associated seeding activity in skeletal muscles of CWD-infected cervids. The presence of PrPTSE was detected by Western- and postfixed frozen tissue blotting, while the seeding activity of PrPTSE was revealed by protein misfolding cyclic amplification (PMCA). The concentration of PrPTSE in skeletal muscles of CWD-infected WTD was estimated to be approximately 2000- to 10000-fold lower than in brain tissue. Tissue-blot-analyses revealed that PrPTSE was located in muscle- associated nerve fascicles but not, in detectable amounts, in myocytes. The presence and seeding activity of PrPTSE in skeletal muscle from CWD-infected cervids suggests prevention of such tissue in the human diet as a precautionary measure for food safety, pending on further clarification of whether CWD may be transmissible to humans.
Sunday, January 22, 2012
Chronic Wasting Disease CWD cervids interspecies transmission
now, let’s see what the authors said about this casual link, personal communications years ago. see where it is stated NO STRONG evidence. so, does this mean there IS casual evidence ??
“Our conclusion stating that we found no strong evidence of CWD transmission to humans”
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"
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
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
Sent: Sunday, September 29, 2002 10:15 AM
To: firstname.lastname@example.org; email@example.com; ebb8@CDC.GOV
Subject: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS
Sunday, November 10, 2002 6:26 PM ......snip........end..............TSS
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
*** twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center***,
full text ;
CWD ongoing experiment on humans, long term $$$
Monday, November 14, 2011
WYOMING Creutzfeldt Jakob Disease, CWD, TSE, PRION REPORTING 2011
Wednesday, November 16, 2011
Wisconsin Creutzfeldt Jakob Disease, CWD, TSE, PRION REPORTING 2011
Sunday, November 13, 2011
COLORADO CWD CJD TSE PRION REPORTING 2011
PLUS, THE CDC DID NOT PUT THIS WARNING OUT FOR THE WELL BEING OF THE DEER AND ELK ;
Thursday, May 26, 2011
Travel History, Hunting, and Venison Consumption Related to Prion Disease Exposure, 2006-2007 FoodNet Population Survey
Journal of the American Dietetic Association Volume 111, Issue 6 , Pages 858-863, June 2011.
NOR IS THE FDA 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
Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge Spencers Lane BerksWell Coventry CV7 7BZ
Dear Mr Elmhirst,
CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT
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.