Temporal dynamics of PRNP haplotype frequencies and optimization of selection strategies for scrapie resistance in the Valle del Belìce sheep breed
Temporal dynamics of PRNP haplotype frequencies and optimization of selection strategies for scrapie resistance in the Valle del Belìce sheep breed
Autori: Riggio, S.; Mastrangelo, S.; Carta, F.; Portolano, B.; Sardina, M.T.
Anno di pubblicazione: 2026
Tipologia: Articolo in rivista
OA Link: http://hdl.handle.net/10447/716523
Abstract
Scrapie is a fatal transmissible spongiform encephalopathy affecting small ruminants, with susceptibility strongly influenced by polymorphisms in the prion protein gene (PRNP). The aim of this study was to evaluate trends in PRNP haplotype and genotype frequencies in the Valle del Belìce sheep breed before and after the implementation of the Sicilian scrapie Resistance Plan. Furthermore, a simulation analysis was performed to assess the expected genetic response under a revised selection strategy. A total of 4341 animals were genotyped for the PRNP gene. In the overall population, ARR (0.543) and ARQ (0.406) were the most frequent haplotypes. In animals born before the implementation of the selection plan (pre-2016), the frequency of the ARR haplotype was 0.462 (females = 0.459; males = 0.537). In animals born after the introduction of the plan, ARR frequency increased to 0.589 (females = 0.566; males = 0.774), reflecting the greater selection intensity applied to breeding rams. These results support the effectiveness of targeted genetic selection in increasing the frequency of the resistant ARR haplotype, while emphasizing the often-overlooked role of ewes as a reservoir of susceptible genotypes. Simulation results suggest that extending selection to ewes and implementing controlled mating schemes could accelerate genetic progress, leading to near-fixation of the ARR haplotype within approximately seven to eight years. This study demonstrates that the inclusion of the entire breeding population is essential to optimize scrapie resistance programs. The findings provide a quantitative basis for revising current regional guidelines and offer broader insights for the design of sustainable genetic control strategies.
https://www.unipa.it/persone/docenti/p/baldassare.portolano/?pagina=pubblicazione&idPubblicazione=1087990
Vet. Res. 38 (2007) 65-80 DOI: 10.1051/vetres:2006046
Epidemiological and genetical differences between classical and atypical scrapie cases
Gesine Lühkena, Anne Buschmannb, Horst Brandta, Martin Eidenb, Martin H. Groschupb and Georg Erhardta
a Department of Animal Breeding and Genetics, Justus-Liebig University of Giessen, 35390 Giessen, Germany b Friedrich-Loeffler Institute (FLI), Institute for Novel and Emerging Infectious Diseases, 17493 Greifswald-Insel Riems, Germany
(Received 16 June 2006; accepted 13 September 2006; published online 8 December 2006) Abstract - The aim of this study was to analyze the epidemiology and prion protein (PrP) genetics in scrapie-affected sheep flocks in Germany. For this purpose, 224 German scrapie cases in sheep diagnosed between January 2002 and February 2006 were classified as classical or atypical scrapie and the amino acids at codons 136, 141, 154 and 171 were determined. Likewise, representative numbers of flock mates were genotyped. Significant epidemiological differences were observed between classical and atypical scrapie cases in regard to the numbers of scrapie-affected sheep within a flock, the sizes of flocks with only a single scrapie-positive sheep or more than one scrapie-positive sheep and the age distribution of the scrapie-positive sheep. Sheep with the ARQ/ARQ genotype had by far the highest risk for acquiring classical scrapie, but the risk for atypical scrapie was the highest for sheep carrying phenylalanine (F) at position 141 (AF141RQ) and/or the AHQ haplotype. However, atypical scrapie also occurred with a notable frequency in sheep with the PrP haplotypes ARR and/or ARQ in combination with Leucine at position 141 (AL141RQ). Furthermore, six atypical scrapie-positive sheep carried the PrP genotype ARR/ARR. The high proportion of sheep flocks affected by atypical scrapie underscores the importance of this scrapie type.
Key words: sheep / classical scrapie / atypical scrapie / epidemiology / PrP polymorphisms
Corresponding author: Gesine.Luehken@agrar.uni-giessen.de
© INRA, EDP Sciences 2007
https://www.vetres.org/articles/vetres/abs/2007/01/v06219/v06219.html
“Sheep with the ARQ/ARQ genotype had by far the highest risk for acquiring classical scrapie, but the risk for atypical scrapie was the highest for sheep carrying phenylalanine (F) at position 141 (AF141RQ) and/or the AHQ haplotype. However, atypical scrapie also occurred with a notable frequency in sheep with the PrP haplotypes ARR and/or ARQ in combination with Leucine at position 141 (AL141RQ). ***> Furthermore, six atypical scrapie-positive sheep carried the PrP genotype ARR/ARR. The high proportion of sheep flocks affected by atypical scrapie underscores the importance of this scrapie type.” <***
***> Furthermore, six atypical scrapie-positive sheep carried the PrP genotype ARR/ARR. The high proportion of sheep flocks affected by atypical scrapie underscores the importance of this scrapie type.” <***
J Vet Sci. 2013 Mar 24;14(1):45–51. doi: 10.4142/jvs.2013.14.1.45
Trends in genotype frequency resulting from breeding for resistance to classical scrapie in Belgium (2006~2011)
Alexandre Dobly 1,✉, Sara Van der Heyden 1, Stefan Roels 1 Author information PMCID: PMC3615231 PMID: 23388443
Abstract
In sheep, susceptibility to scrapie is mainly determined by codons 136, 154, and 171 of the PRNP gene. Five haplotypes are usually present (ARR, ARQ, ARH, AHQ, and VRQ). The ARR haplotype confers the greatest resistance to classical scrapie while VRQ renders animals most susceptible. In 2004, the European Union implemented a breeding program that promotes selection of the ARR haplotype while reducing the incidence of VRQ. From 2006 to 2011 in Belgium, frequency for the ARR/ARR genotypes increased from 38.3% to 63.8% (n = 6,437), the ARQ haplotype diminished from 21.1% to 12.9%, and the VRQ haplotype decreased from 2.0% to 1.7%. The status of codon 141, a determinant for atypical scrapie, was also evaluated. Out of 27 different breeds (n = 5,163), nine were abundant. The ARR/ARR frequency increased in eight of these nine major breeds. The selection program has had a major impact on the ARR haplotype frequency in Belgium. However, the occurrence of atypical scrapie represents a critical point for this program that warrants the continuous monitoring of scrapie. Additionally, genotype frequencies among the breeds varied greatly. Texel, a breed that is common in Belgium, can still be selected for due to its average ARR frequency.
snip…
In 1998, an atypical form of scrapie was discovered in Norway and named Nor98 [5]. Since then, this type of scrapie has been described in several European Union (EU) member states including Belgium [6,7,15]. It is not yet clear whether Nor98 is a transmissible disease in the field or whether it represents a sporadic disease. Genetic resistance to this specific form is not the same as that observed for classical scrapie. Sheep with the ARR/ARR genotype do not seem to have resistance to Nor98. Cases of Nor98, including those occurring in Belgium, have been described in animals with ARR/ARR genotypes [8,28]. However, ARR/ARR sheep are not the most susceptible to atypical scrapie since a polymorphism situated at a fourth codon [leucine (L) or phenylalanine (F) at codon 141] also affects susceptibility to this form of scrapie [32]. Most atypical scrapie cases have been detected in sheep with F at codon 141 (F141). It seems that the haplotype ARQ with F141 (noted as AF141RQ) is associated with greater susceptibility to atypical scrapie [28,35]. Similarly, the AL141HQ haplotype confers susceptibility to atypical scrapie [31].
https://vetsci.org/DOIx.php?id=10.4142/jvs.2013.14.1.45
“Genetic resistance to this specific form is not the same as that observed for classical scrapie. Sheep with the ARR/ARR genotype do not seem to have resistance to Nor98.”
Classical scrapie transmission in ARR/ARR genotype sheep
No Access Caroline Lacroux1,†, Hervé Cassard1,†, Hugh Simmons2, Jean Yves Douet1, Fabien Corbière1, Severine Lugan1, Pierette Costes1, Naima Aron1, Alvina Huor1, Cécile Tillier1, Francois Schelcher1 and Olivier Andreoletti1 View Affiliations Published: 01 August 2017 https://doi.org/10.1099/jgv.0.000861
Abstract
The ARR allele is considered to provide a very strong resistance against classical scrapie infection in sheep. In this study, we report the occurrence of clinical transmissible spongiform encephalopathy in ARR/ARR sheep, following their inoculation by the intracerebral route with a classical scrapie isolate. On first passage, the disease displayed an incomplete attack rate transmission, with incubation periods exceeding 6 years. On second passage, the obtained prion did not display better abilities to propagate than the original isolate. These transmission results contrasted with the 100 % attack rate and the short incubation periods observed in ARQ/ARQ sheep challenged with the same isolate. These data confirm that ARR/ARR sheep cannot be considered to be fully resistant to classical scrapie. However, they also support the contention that classical scrapie has a very limited capacity to transmit and adapt to ARR/ARR sheep.
Received: 27/04/2017 Accepted: 12/06/2017 Published Online: 01/08/2017 Keyword(s): ARR allele , classical scrapie , geneticresistance , prion and sheep
https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000861
Pathogenesis, detection, and control of scrapie in sheep
Authors: DVM, PhD and DVM, PhD
Free access Abstract Full Text PDF Article Metrics PubMed
Abstract
In sheep, scrapie is a fatal neurologic disease that is caused by a misfolded protein called a prion (designated PrPSc). The normal cellular prion protein (PrPC) is encoded by an endogenous gene, PRNP, that is present in high concentrations within the CNS. Although a broad range of functions has been described for PrPC, its entire range of functions has yet to be fully elucidated. Accumulation of PrPSc results in neurodegeneration. The PRNP gene has several naturally occurring polymorphisms, and there is a strong correlation between scrapie susceptibility and PRNP genotype. The cornerstone of scrapie eradication programs is the selection of scrapie-resistant genotypes to eliminate classical scrapie. Transmission of classical scrapie in sheep occurs during the prenatal and periparturient periods when lambs are highly susceptible. Initially, the scrapie agent is disseminated throughout the lymphoid system and into the CNS. Shedding of the scrapie agent occurs before the onset of clinical signs. In contrast to classical scrapie, atypical scrapie is believed to be a spontaneous disease that occurs in isolated instances in older animals within a flock. The agent that causes atypical scrapie is not considered to be naturally transmissible. Transmission of the scrapie agent to species other than sheep, including deer, has been experimentally demonstrated as has the transmission of nonscrapie prion agents to sheep. The purpose of this review is to outline the current methods for diagnosing scrapie in sheep and the techniques used for studying the pathogenesis and host range of the scrapie agent. Also discussed is the US scrapie eradication program including recent updates.
Even though sheep with the ARR/ARR genotype are highly resistant to the scrapie agent, naturally occurring classical scrapie disease has been reported in at least 3 sheep with that genotype.77,78
Summary
Scrapie is a naturally occurring and fatal neurologic disease of sheep that is caused by a misfolded protein called a prion. The tendency and efficiency of scrapie transmission between sheep is dependent on the compatibility between the donor's and recipient's PrPCgenotype. Two major tenets of the US NSEP are selective breeding of sheep with scrapie-resistant genotypes and surveillance. Sheep with the ARR/ARR genotype are considered to be relatively resistant and sheep with the VRQ/VRQ genotype are highly susceptible to the classical scrapie agent. Definitive diagnosis of scrapie in live animals can be challenging, and negative results on antemortem diagnostic tests should be interpreted with caution and confirmed with serial testing. The NSEP has been successful in decreasing the prevalence of scrapie in sheep and goats in the United States; however, continued monitoring and research to better understand the epidemiology of scrapie and other TSEs are important. Elucidation of the host range for the scrapie agent may also advance knowledge regarding the origins of other TSEs. Interspecies transmission of TSE agents has been experimentally demonstrated, but it is considered unlikely under natural conditions. Nonetheless, information gleaned from research of interspecies transmission of infectious prion agents is useful for developing risk assessments and recommending agricultural practices that facilitate scrapie eradication.
“Even though sheep with the ARR/ARR genotype are highly resistant to the scrapie agent, naturally occurring classical scrapie disease has been reported in at least 3 sheep with that genotype.77,78”
https://avmajournals.avma.org/view/journals/ajvr/81/7/ajvr.81.7.600.xml
“a The agent that causes atypical scrapie is not considered to be naturally transmissible.”
Atypical Scrapie
***> “The WOAH and APHIS determined that it is not a disease of trade concern.” <***
concerned! why?
***> Incomplete inactivation of atypical scrapie following recommended autoclave decontamination procedures <***
John Spiropoulos Richard Lockey Katy E. Beck Chris Vickery Thomas M. Holder Leigh Thorne Mark Arnold Olivier Andreoletti Marion M Simmons Linda A. Terry First published: 21 May 2019 https://doi.org/10.1111/tbed.13247 Please cite this article as doi: 10.1111/tbed.13247
Summary Prions are highly resistant to the decontamination procedures normally used to inactivate conventional pathogens. This is a challenging problem not only in the medical and veterinary fields for minimising the risk of transmission from potentially infective sources, but also for ensuring the safe disposal or subsequent use of animal by‐products. Specific pressure autoclaving protocols were developed for this purpose, but different strains of prions have been reported to have differing resistance patterns to established prion decontamination procedures, and as additional TSE strains are identified it is necessary to determine the effectiveness of such procedures. In this study we assessed the efficacy of sterilisation using the EU recommended autoclave procedure for prions (133o C, 3 Bar for 20 min) on the atypical or Nor98 (AS/Nor98) scrapie strain of sheep and goats. Using a highly sensitive murine mouse model (tg338) that overexpresses ovine PrPC, we determined that this method of decontamination reduced the infectivity titre by 1010. Infectivity was nonetheless still detected after applying the recommended autoclaving protocol. This shows that AS/Nor98 can survive the designated legislative decontamination conditions, albeit with a significant decrease in titre. The infectivity of a classical scrapie isolate subjected to the same decontamination conditions was reduced by 106 suggesting that the AS/Nor98 isolate is less sensitive to decontamination than the classical scrapie source. This article is protected by copyright. All rights reserved.
https://onlinelibrary.wiley.com/doi/abs/10.1111/tbed.13247
WEDNESDAY, MAY 29, 2019
***> Incomplete inactivation of atypical scrapie following recommended autoclave decontamination procedures
https://nor-98.blogspot.com/2019/05/incomplete-inactivation-of-atypical.html
THURSDAY, DECEMBER 31, 2020
Autoclave treatment of the classical scrapie agent US No. 13-7 and experimental inoculation to susceptible VRQ/ARQ sheep via the oral route results in decreased transmission efficiency
https://scrapie-usa.blogspot.com/2020/12/autoclave-treatment-of-classical.html
Snip…see full text;
https://nor-98.blogspot.com/2021/01/atypical-nor-98-scrapie-tse-prion-usa.html
Saturday, May 2, 2009
APHIS AND WHO PLAN TO EXEMPT THE ATYPICAL SCRAPIE NOR-98 FROM REGULATIONS AT MEETING THIS MONTH
http://nor-98.blogspot.com/2009/05/aphis-and-who-plan-to-exempt-atypical.html
Monday, November 30, 2009
USDA AND OIE COLLABORATE TO EXCLUDE ATYPICAL SCRAPIE NOR-98 ANIMAL HEALTH CODE
http://nor-98.blogspot.com/2009/11/usda-and-oie-collaborate-to-exclude.html
Thursday, December 20, 2012
OIE GROUP RECOMMENDS THAT SCRAPE PRION DISEASE BE DELISTED AND SAME OLD BSe WITH BOVINE MAD COW DISEASE
http://transmissiblespongiformencephalopathy.blogspot.com/2012/12/oie-group-recommends-that-scrape-prion.html
Experimental transmission of ovine atypical scrapie to cattle
Timm Konold, John Spiropoulos, Janet Hills, Hasina Abdul, Saira Cawthraw, Laura Phelan, Amy McKenna, Lauren Read, Sara Canoyra, Alba Marín-Moreno & Juan María Torres
Veterinary Research volume 54, Article number: 98 (2023)
Abstract
Classical bovine spongiform encephalopathy (BSE) in cattle was caused by the recycling and feeding of meat and bone meal contaminated with a transmissible spongiform encephalopathy (TSE) agent but its origin remains unknown. This study aimed to determine whether atypical scrapie could cause disease in cattle and to compare it with other known TSEs in cattle. Two groups of calves (five and two) were intracerebrally inoculated with atypical scrapie brain homogenate from two sheep with atypical scrapie. Controls were five calves intracerebrally inoculated with saline solution and one non-inoculated animal. Cattle were clinically monitored until clinical end-stage or at least 96 months post-inoculation (mpi). After euthanasia, tissues were collected for TSE diagnosis and potential transgenic mouse bioassay. One animal was culled with BSE-like clinical signs at 48 mpi. The other cattle either developed intercurrent diseases leading to cull or remained clinical unremarkable at study endpoint, including control cattle. None of the animals tested positive for TSEs by Western immunoblot and immunohistochemistry. Bioassay of brain samples from the clinical suspect in Ov-Tg338 and Bov-Tg110 mice was also negative. By contrast, protein misfolding cyclic amplification detected prions in the examined brains from atypical scrapie-challenged cattle, which had a classical BSE-like phenotype. This study demonstrates for the first time that a TSE agent with BSE-like properties can be amplified in cattle inoculated with atypical scrapie brain homogenate.
snip...
This is the first study in cattle inoculated with naturally occurring scrapie isolates that found the presence of prions resembling classical BSE in bovine brain although this was limited to detection by the ultrasensitive PMCA. The results from thermostability assay confirmed that the isolates were as thermoresistant as the BSE agent as proven in other studies [36, 48]. Previous PMCA studies with various British atypical scrapie isolates did not find any evidence of amplification [49, 50]. This may be explained by the use of ovine brain as substrate rather than brain from Bov-Tg110 mice, which may facilitate conversion to classical BSE prions.
Two hypotheses for prion strain propagation in cross-species transmission experiments have been proposed: conformational selection favours a particular strain conformation out of a mixture of conformations in a scrapie isolate whilst mutation results in the conformational shift of one conformation into another [51]. Following on from the study in mice [17], it has been subsequently suggested that classical BSE properties that arise in atypical scrapie isolates transmitted to cattle may be due to conformational mutation in a new host [52]. It does not confirm that the atypical scrapie agent is the origin of the classical BSE epidemic and further transmission studies would be required to see whether classical BSE can be generated.
Would PMCA applied to brains from cattle exposed to TSE agents other than classical BSE and atypical scrapie also produce a classical BSE-like molecular phenotype? The PMCA product obtained in the thermostability test using a thermosensitive classical scrapie control showed a profile unlike classical BSE. Atypical BSE has been linked to the origin of classical BSE because of its conversion into classical BSE following serial passages in wild-type mice (L-type BSE [11]) and bovine transgenic mice (H-type BSE [53]). Although we have not tested PMCA products of atypical BSE isolates as part of this study, there is no evidence that PMCA products from atypical BSE convert into classical BSE, at least for H-type BSE using bovine brain as substrate [54]. In fact, we were unable to propagate H-type BSE using the same methodology (S Canoyra, A Marín-Moreno, JM Torres, unpublished observation).
The study results support the decision to maintain the current ban on animal meal in feedstuffs for ruminants, particularly as atypical scrapie occurs world-wide, and eradication is unlikely for a sporadic disease.
In summary, experimental inoculation of cattle with the atypical scrapie agent may produce clinical disease indistinguishable from classical BSE, which cannot be diagnosed by conventional diagnostic tests, but prions can be amplified by ultrasensitive tests in both clinically affected and clinically unremarkable cattle, which reveal classical BSE-like characteristics. Further studies are required to assess whether a BSE-like disease can be confirmed by conventional tests, which may initially include a second passage in cattle.
https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-023-01224-3
Volume 17, Number 5—May 2011
Research
Experimental Oral Transmission of Atypical Scrapie to Sheep
Marion M. SimmonsComments to Author , S. Jo Moore1, Timm Konold, Lisa Thurston, Linda A. Terry, Leigh Thorne, Richard Lockey, Chris Vickery, Stephen A.C. Hawkins, Melanie J. Chaplin, and John Spiropoulos
Author affiliations: Author affiliation: Veterinary Laboratories Agency–Weybridge, Addlestone, UK Cite This Article
Abstract
To investigate the possibility of oral transmission of atypical scrapie in sheep and determine the distribution of infectivity in the animals’ peripheral tissues, we challenged neonatal lambs orally with atypical scrapie; they were then killed at 12 or 24 months. Screening test results were negative for disease-specific prion protein in all but 2 recipients; they had positive results for examination of brain, but negative for peripheral tissues. Infectivity of brain, distal ileum, and spleen from all animals was assessed in mouse bioassays; positive results were obtained from tissues that had negative results on screening. These findings demonstrate that atypical scrapie can be transmitted orally and indicate that it has the potential for natural transmission and iatrogenic spread through animal feed. Detection of infectivity in tissues negative by current surveillance methods indicates that diagnostic sensitivity is suboptimal for atypical scrapie, and potentially infectious material may be able to pass into the human food chain.
Snip…
Discussion This study is still ongoing and will not be completed until 2012. However, the current interim report documents the successful oral transmission of atypical scrapie, confirms that the disease phenotype is retained following transmission by this route in AHQ/AHQ sheep, and indicates that infectivity can be demonstrated in the gut in the absence of detectable PrPSc at least as early as 12 months after exposure.
One sheep (animal 12) culled at 24 months post inoculation displayed abnormalities in behavior and movement suggestive of atypical scrapie. Signs like ataxia with head tremor and circling have been described in experimental (19) and natural (3,30) disease, which was attributed to lesions in the cerebellum and forebrain, respectively, corresponding with PrPSc accumulation in these areas (20,24).
By contrast, animal 11, which had confirmed atypical scrapie based on postmortem tests, was considered clinically normal. The less severe and limited PrPSc accumulation in the brain of this sheep than in animal 12 may explain the absence of clinical abnormalities, which is supported by our findings in goats with scrapie in which more extensive PrPSc accumulation in the brain was usually associated with a more severe clinical disease (25).
Although all TSEs are transmissible after intracerebral challenge to a susceptible host, only some are infectious under natural conditions. Therefore, it was important from a pathogenesis and disease control perspective to establish whether or not oral transmission can be successful. However, the challenge model in this study exposed animals as neonates, when the esophageal groove is operational and the lambs are physiologically monogastric. Exposure of 3-month-old ruminating animals to similar amounts of positive brain by the oral route have so far not resulted in any clinical disease, with all animals still alive >1,500 days post challenge (M.M. Simmons, unpub. data), but most natural cases have been recorded in animals older than this, so these animals may still progress to disease in the next few years. Since this challenge study in older animals has no time-kill component, and no losses caused by unrelated disease have occurred, whether any of these sheep are in a preclinical phase of disease is unknown. Unfortunately, the absence of detectable PrPSc in lymphoreticular tissues of sheep with atypical scrapie precludes the use of biopsies to ascertain early infection in these animals.
Transmission may be more efficient in newborn animals; the incubation periods of sheep orally infected with classical scrapie were significantly shorter in sheep challenged at 14 days of age than those challenged at 6 months of age (31). If, however, oral transmission is only effective in such young animals, then field exposure would most likely have to be through milk, which is known to be a highly effective route of transmission for classical scrapie (32). No data are currently available on the potential infectivity of milk from animals with atypical scrapie.
Successful oral transmission also raises questions regarding the pathogenesis of this form of disease. There must be passage of the infectious agent from the alimentary canal to the brain through one of several possible routes, most likely those that have been suggested and discussed in detail for other TSEs, for example, retrograde neuronal transportation either directly (33–35) or through lymphoid structures or hematogenously (36). Infectivity in the absence of readily demonstrable PrPSc has been reported (37–39), and although the mouse bioassay may detect evidence of disease in other tissues, these data may not be available for at least another 2 years. More protease-sensitive forms of PrPSc may be broken down more efficiently within cells and thus do not accumulate in peripheral tissues (19), enabling atypical PrPSc to transit the digestive tract and disseminate through other systems in small amounts before accumulating detectably in the central nervous system.
Although we do not have epidemiologic evidence that supports the efficient spread of disease in the field, these data imply that disease is potentially transmissible under field situations and that spread through animal feed may be possible if the current feed restrictions were to be relaxed. Additionally, almost no data are available on the potential for atypical scrapie to transmit to other food animal species, certainly by the oral route. However, work with transgenic mice has demonstrated the potential susceptibility of pigs, with the disturbing finding that the biochemical properties of the resulting PrPSc have changed on transmission (40). The implications of this observation for subsequent transmission and host target range are currently unknown.
How reassuring is this absence of detectable PrPSc from a public health perspective? The bioassays performed in this study are not titrations, so the infectious load of the positive gut tissues cannot be quantified, although infectivity has been shown unequivocally. No experimental data are currently available on the zoonotic potential of atypical scrapie, either through experimental challenge of humanized mice or any meaningful epidemiologic correlation with human forms of TSE. However, the detection of infectivity in the distal ileum of animals as young as 12 months, in which all the tissues tested were negative for PrPSc by the currently available screening and confirmatory diagnostic tests, indicates that the diagnostic sensitivity of current surveillance methods is suboptimal for detecting atypical scrapie and that potentially infectious material may be able to pass into the human food chain undetected.
https://wwwnc.cdc.gov/eid/article/17/5/10-1654_article
See updated studies on AS
Meeting-book-final-version prion 2023 Prion 2023 Congress Organizing Committee and the NeuroPrion Association, we invite you to join us for the International Conference Prion2023 from 16-20 October 2023 in Faro, Portugal.
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
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https://www.researchgate.net/profile/Syed-Zahid-Shah/publication/378314391_Meeting-book-final-version_prion_2023/links/65d44dad28b7720cecdca95f/Meeting-book-final-version-prion-2023.pdf
Comparing the Distribution of Ovine Classical Scrapie and Sporadic Creutzfeldt-Jakob Disease in Italy: Spatial and Temporal Associations (2002-2014)
Ru G1 ., Pocchiari M2 ., Bertolini S. 1, Pite L.1 , Puopolo M.2 , Ladogana A.2 , Perrotta M.G.3 , Meloni D 1 . (1) National reference center for the study and research on animal encephalopathies and comparative neuropathologies (CEA). Experimental Zooprophylactic Institute of Piemonte, Liguria and Valle d'Aosta, Torino, Italy.
(2) Department of Cellular Biology and Neuroscience, Istituto Superiore di Sanità, Roma, Italy. (3) Office 3 National center for the fight and emergency against animal diseases. Ministry of Health, Roma, Italy.
Aim: This study aims to investigate potential spatial and temporal associations between Creutzfeldt-Jakob disease (CJD) in humans (2010-2014) and ovine classical scrapie (CS) (2002- 2006) in Italy, serving as a proxy for exposure.
Materials and Methods: National data from prion disease surveillance in humans (sporadic CJD) and small ruminants (CS) in Italy were utilized. A descriptive geographic analysis was conducted for each disease individually. Subsequently, an ecological study was performed to compare the occurrence of both diseases at the district and regional levels. Standardized incidence ratios (SIR), adjusted for confounders, were calculated for CJD and CS by district and region, respectively, representing the outcome and proxy of exposure. Considering a possible long incubation period of CJD, two study periods were analysed: 2010-2014 for CJD and 2002-2006 for CS. Eight alternative linear regression models were developed using SIR in humans as the dependent variable and SIR in sheep as the independent variable. These models varied in the scale of SIR data (continuous vs. categorical), geographical level (district vs. region), and the potential past exposure of sheep in specific areas to a known source of infection (via a contaminated vaccine).
Results: The analysis of data at the district level revealed no significant association. However, when considering aggregated regional data, all four models consistently indicated a statistically significant positive association, suggesting a higher incidence of the disease in humans as the regional incidence of sheep scrapie increased.
Conclusions: While the results are intriguing, it is important to acknowledge the inherent limitations of ecological studies. Nevertheless, these findings provide valuable evidence to formulate a hypothesis regarding the zoonotic potential of classical scrapie. Further investigations are necessary, employing specific designs such as analytical epidemiology studies, to test this hypothesis effectively.
Funded by: Italian Ministry of Health Grant number: Realizzazione del programma epidemiologico finalizzato a dare evidenza del potenziale zoonotico delle TSE animali diverse dalla BSE. Prot. N. 0018730-17/07/2015-DGSAFCOD_UO-P
''Nevertheless, these findings provide valuable evidence to formulate a hypothesis regarding the zoonotic potential of classical scrapie. Further investigations are necessary, employing specific designs such as analytical epidemiology studies, to test this hypothesis effectively.''
Meeting-book-final-version prion 2023 Prion 2023 Congress Organizing Committee and the NeuroPrion Association, we invite you to join us for the International Conference Prion2023 from 16-20 October 2023 in Faro, Portugal.
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
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Transmission of Idiopathic human prion disease CJD MM1 to small ruminant mouse models (Tg338 and Tg501).
Enric Vidal1,2, Samanta Giler1,2, Montse Ordóñez1,2, Hasier Eraña3,4, Jorge M. Charco3,4, Guillermo Cantero1,2, Juan C. Espinosa5 , Juan M. Torres5 , Vincent Béringue6 , Martí Pumarola7 and Joaquín Castilla3,8,9
Aims: About 90% of Creutzfeldt-Jakob disease cases are classified as sporadic (sCJD), that is, occur infrequently, randomly and without a known cause. It is a fatal neurodegenerative disease with an incidence of 1-1.5 cases per million per year. Epidemiological studies have been so far unable to establish a causal relationship between sCJD and prion diseases in animals.
The zoonotic potential of sheep scrapie was demonstrated in 2014 (Cassard et al., Nature Communications) through inoculation of transgenic mice overexpressing the human prion protein with scrapie isolates. The resulting prion disease was indistinguishable from that occurring after sCJD inoculation in the same model and, while these results do not demonstrate that sCJD is caused by scrapie prions, they do show that the transmission barrier between ovine and human prions is not absolute. Our aim is to further assess this zoonotic risk.
Materials and methods: we have prepared inocula from 3 sCJD cases (MM1, MV2 and VV2) and 2 VPSPr cases (MM and MV) to verify if it is possible to recover the scrapie phenotype upon inoculation in Tg338 and Tg501 ovinized mouse models. Additionally, two different inocula gCJD (E200K) and GSS (A117V) have been also included in the bioassays as controls for classical and atypical genetic human prions, respectively.
Results: No evidence of transmission was found on a first passage in Tg338 nor Tg501 ovinized mice, but on second passage, 4/10 Tg338 mice succumbed to CJDMM1 (40% attack rate after 645 dpi) and 1/12Tg501 mice (519dpi, 10 still alive). The remaining 2nd passages are still ongoing. Conclusions: In this poster, the neuropathological features of the resulting strain are discussed.
Funded by: MINECO grant number AGL2017-88535-P and PID2021-1222010B-C22 and by Interreg POCTEFA grant number EFA148/16 (RedPRION)
''but on second passage, 4/10 Tg338 mice succumbed to CJDMM1 (40% attack rate after 645 dpi) and 1/12 Tg501 mice (519dpi, 10 still alive). The remaining 2nd passages are still ongoing. Conclusions: In this poster, the neuropathological features of the resulting strain are discussed.''
Meeting-book-final-version prion 2023 Prion 2023 Congress Organizing Committee and the NeuroPrion Association, we invite you to join us for the International Conference Prion2023 from 16-20 October 2023 in Faro, Portugal.
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://web.archive.org/web/20250828201533/https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://www.researchgate.net/profile/Syed-Zahid-Shah/publication/378314391_Meeting-book-final-version_prion_2023/links/65d44dad28b7720cecdca95f/Meeting-book-final-version-prion-2023.pdf
*** Grant Agreement number: 222887 ***
*** Project acronym: PRIORITY ***
*** Project title: Protecting the food chain from prions: shaping European priorities through basic and applied research Funding ***
Scheme: Large-scale integrating project Period covered: from Oct. 1, 2009 to Sept. 30, 2014
Name of the scientific representative of the project's co-ordinator1, Title and Organisation: Jesús R. Requena, Ph.D., Associate Professor, Department of medicine, University of Santiago de Compostela, Spàin. Tel: 34-881815464 Fax: 34-881815403 E-mail: jesus.requena@usc.es
Project website¡ Error! Marcador no definido. address: www.prionpriority.eu
PRIORITY, PROJECT FINAL REPORT
*** 14) Concluding that atypical scrapie can transmit to Humans and that its strain properties change as it transmits between species ***
snip...
http://cordis.europa.eu/docs/results/222/222887/final1-priority-final-report.pdf
see full text;
Block D: Prion epidemiology
Studies on atypical scrapie were identified as a key element of this block, given the potential risk associated to this agent. We studied the permeability of Human, bovine and porcine species barriers to atypical scrapie agent transmission. Experiments in transgenic mice expressing bovine, porcine or human PrPC suggest that this TSE agent has the intrinsic ability to propagate across these species barriers including the Human one. Upon species barrier passage the biological properties and phenotype of atypical scrapie seem to be altered. Further experiments are currently ongoing (in the framework of this project but also in other projects) in order to: (i) characterize the properties of the prion that emerged from the propagation of atypical scrapie in tg Hu; (ii) to confirm that the phenomena we observed are also true for atypical scrapie isolates other than the ones we have studied.
In parallel, studies in sheep have concluded that:
*** Atypical scrapie can be transmitted by both oral and intracerebral route in sheep with various PRP genotypes
*** Low but consistent amount of infectivity accumulates in peripheral tissue (mammary gland, lymph nodes, placenta, skeletal muscles, nerves) of sheep incubating atypical scrapie.
*** The combination of data from all our studies leads us to conclude that:
*** Atypical scrapie passage through species barriers can lead to the emergence of various prions including classical BSE (following propagation in porcine PRP transgenic mice).
*** Atypical scrapie can propagate, with a low efficacy, in human PrP expressing mice. This suggests the existence of a zoonotic potential for this TSE agent.
snip...
We advance our main conclusions and recommendations, in particular as they might affect public policy, including a detailed elaboration of the evidence that led to them. Our main recommendations are:
a. The issue of re-introducing ruminant protein into the food-chain The opinion of the members of Priority is that sustaining an absolute feed ban for ruminant protein to ruminants is the essential requirement, especially since the impact of non-classical forms of scrapie in sheep and goats is not fully understood and cannot be fully estimated. Therefore, the consortium strongly recommends prohibiting re-introduction of processed ruminant protein into the food-chain. Arguments in support of this opinion are:
• the large (and still uncharacterized) diversity of prion agents that circulate in animal populations;
• the uncertainties related to prion epidemiology in animal populations;
• the unknown efficacy of industrial processes applied to reduce microbiological risk during processed animal protein (PAP) production on most prion agents; • the intrinsic capacity of prions to cross interspecies transmission barriers; • the lack of sensitive methodology for identifying cross contamination in food.
• the evolution of natural food chains in nature (i.e. who eats whom or what) has generated an efficient barrier preventing, to some extent, novel prion epidemies and that this naturally evolved ecology should be respected.
The consortium is also hesitant to introduce processed ruminant proteins into fish food considering the paucity of data on prion infections in fishes and sea animals including those of mammalian origin, and the risk of establishing an environmental contamination of the oceans that cannot be controlled.
b. Atypical prion agents and surveillance
Atypical prion agents (see below) will probably continue to represent the dominant form of prion diseases in the near future, particularly in Europe.
*** Atypical L-type BSE has clear zoonotic potential, as demonstrated in experimental models.
*** Similarly, there are now some data that seem to indicate that the atypical scrapie agent can cross various species barriers.
*** Moreover, the current EU policy for eradicating scrapie (genetic selection in affected flocks) is ineffective for preventing atypical scrapie.
*** The recent identification of cell-to-cell propagation and the protein-encoded strain properties of human neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, suggest that they bear the potential to be transmissible even if not with the same efficiency as CJD. More epidemiological data from large cohorts are necessary to reach any conclusion on the impact of their transmissibility on public health. Re-evaluations of safety precautions may become necessary depending on the outcome of these studies. In that context it would appear valuable
• to develop knowledge related to the pathogenesis and inter-individual transmission of atypical prion agents in ruminants (both intra- and inter-species)
• to improve the sensitivity of detection assays that are applied in the field towards this type of agent
• to maintain a robust surveillance of both animal and human populations
c. The need for extended research on prions
Intensified searching for a molecular determinants of the species barrier is recommended, since this barrier is a key for many important policy areas - risk assessment, proportional policies, the need for screening of human products and food. In this respect, prion strain structural language also remains an important issue for public health for the foreseeable future. Understanding the structural basis for strains and the basis for adaptation of a strain to a new host will require continued fundamental research. Prions maintain a complex two-way relationship with the host cell and fundamental research is needed on mechanisms for their transmission, replication and cause of nervous system dysfunction and death.
Early detection of prion infection, ideally at preclinical stage, also remains crucial for development of effective treatment strategies in humans affected by the disease.
Position of the Priority consortium
Nearly 30 years ago, the appearance in the UK of Bovine Spongiform Encephalopathy (BSE) quickly brought the previously obscure “prion diseases” to the spotlight. The ensuing health and food crises that spread throughout Europe had devastating consequences. In the UK alone, there were more than 36,000 farms directly affected by BSE and the transmission of BSE prions to humans via the food chain has caused over 200 people in Europe to die from variant Creutzfeldt-Jakob disease (vCJD) (http://www.cjd.ed.ac.uk
Origins of prion epidemies
Classical BSE now appears to be under control, with 18 EU Member States having achieved the World Organisation for Animal Health (Office International Epizooties) „negligible risk‟ status (May 2014; http://www.oie.int/en/animal-health-in-the-world/official-disease-status/bse/list-of-bse-risk-status/), and the remaining MS assessed as „controlled‟ risk. Of note, research, including EU-funded research, has played a key role in this success: while the origin of the infection was never defined, the principle driver of the epidemic was identified as prions in Meat and Bone Meal (MBM). Tests based on prion protein-specific antibodies were developed, allowing detection of infected animals, and a better understanding of disease pathogenesis and the distribution of infectivity in edible tissues; experimental investigation of transmission barriers between different species allowed a rational estimation of risks, etc. All of this led to the implementation of rational and effective policies, such as the MBM ban to protect the animal feed chain, and the Specified Risk Material (SRM) regulations to protect the human food chain.
In spite of this progress, prions are still a threat. Epidemiological re-assessment indicates that the ∼10 year incubation period separating the peaks of the BSE and the vCJD epidemics is probably too short. In addition, results from a large number of human tonsil and appendix analyses in the UK suggest that there may be a high number of asymptomatic individuals who are positive for the disease-associated conformer prion protein PrPSc. While vCJD is the only form of human prion disease that has been consistently demonstrated to have lymphoreticular involvement, there has been no systematic investigation of lymphoid tissue in cases with other prion diseases.
The human prion problem
The clinical cases of vCJD identified to date have all shared a common PrP genotype (M129M), although one pre-clinical case was confirmed as an M129V heterozygote, and it has been mooted that perhaps only the M129M proportion of the population is susceptible. However, in the UK appendix study, PrP accumulation was described in samples representing every codon 129 genotype, raising the possibility that genotype does not confer resistance but instead modulates incubation period. Apart from the two UK studies, the lymphoid tissues of non-CJD patients have not been examined for the presence of PrPSc, so, these cases may not solely represent pre-clinical vCJD, but also other forms of prion disease.
Recent experiments in highly susceptible mouse models indicate the presence of infectivity in blood or blood components at late disease stages in sporadic CJD. The significance of this experimental finding for humans has to be explored in more detail and, at the present time, there is no evidence for the transmission of prions via blood in sporadic CJD. However a likely scenario is that all those with signs of infection or abnormal PrP accumulation in peripheral tissue could have infective blood, posing the risk for transmission via blood products, which has been clearly demonstrated in experimental models, and confirmed in several cases of vCJD in man. Altogether, these data clearly demonstrate the potential risk of a second wave of vCJD, particularly when the number people identified with lymphoid accumulation of PrPSc (16/32,411) gives a prevalence estimate in the UK of 493 per million, much higher than the number of clinical cases seen to date.
The animal prion problem
An increasing number of reports on cases of “atypical” BSE in cattle throughout the EU and beyond may lead to a new epidemic, particularly since we still do not understand all factors determining the species barrier. Ovine scrapie is another concern, because it could mask ovine BSE, presumably transmissible to humans. Scrapie is endemic and not likely to be eradicated soon, although current control measures are effective at greatly reducing disease incidence. Atypical forms, which may be spontaneous, are not affected by these control measures and these forms of disease will persist in the global animal population. The low prevalence of these disease forms makes effective surveillance very challenging. However, there is a clear risk attendant on ignoring these cases without an understanding of their possible zoonotic potential, particularly when most forms of human disease have no established aetiology. In summary, atypical cases of BSE and scrapie presently clearly outnumber classical cases in cattle and sheep in all member states.
We will highlight the state-of-the-art knowledge and point out scientific challenges and the major questions for research. Strategic objectives and priorities in Europe in the future for research that aims to control, eliminate or eradicate the threat posed by prions to our food and health are also indicated.
The Priority project has focused on 4 themes, namely the structure, function, conversion and toxicity of prions; detection of prions; mechanisms of prion transmission and spreading and epidemiology of prion diseases. This paper summarizes the opinions/positions reached within these themes at the end of the project.
http://cordis.europa.eu/docs/results/222/222887/final1-priority-final-report.pdf
see;
https://nor-98.blogspot.com/2016/09/goat-k222-prpc-polymorphic-variant-does.html
https://transmissiblespongiformencephalopathy.blogspot.com/2026/04/us-report-scrapie-cwd-cattle-sheep-pigs.html
Final rule on the Importation of Sheep, Goats, and Certain Other Ruminants (APHIS-2009-0095) Scrapie, BSE, CWD, TSE Prion Singeltary Submission
https://scrapie-usa.blogspot.com/2021/12/final-rule-on-importation-of-sheep.html
MAD SHEEP OF MAD RIVER VALLEY
DECLARATION OF EXTRAORDINARY EMERGENCY BECAUSE OF AN ATYPICAL T.S.E. (PRION DISEASE) OF FOREIGN ORIGIN IN THE UNITED STATES [No. 00-072-1] August 15, 2000 OIG case # NY-3399-56 REDACTED, VT
History my 10 year plus FOIA requests and investigation into the truth of infamous Mad Sheep of Mad River Valley!
''Enclosed is OIG's notification that they have scheduled an investigation of the following individual. REDACTED is alleged to have provided possibly inaccurate test results involving diseased sheep. However, because the results were determined to be inconclusive, no actual violation was actually committed.''
https://foiamadsheepmadrivervalley.blogspot.com/
''However, because the results were determined to be inconclusive, no actual violation was actually committed.'' ...confused
http://transmissiblespongiformencephalopathy.blogspot.com/2015/02/aphis-freedom-of-information-act-foia.html
APHIS Freedom of Information Act (FOIA) Appeal Mouse Bio-Assays 2007-00030-A Sheep Imported From Belgium and the Presence of TSE Prion Disease Kevin Shea to Singeltary 2015
IN SHORT ;
August 15, 2000
OIG case # NY-3399-56 REDACTED, VT
''Enclosed is OIG's notification that they have scheduled an investigation of the following individual. REDACTED is alleged to have provided possibly inaccurate test results involving diseased sheep. However, because the results were determined to be inconclusive, no actual violation was actually committed.''
snip...see;
Scrapie TSE Prion, Singeltary review, October 2026
https://scrapie-usa.blogspot.com/2026/10/scrapie-tse-prion-singeltary-review.html
https://prpsc.proboards.com/thread/250/scrapie-prion-singeltary-review-2026
USA atypical Nor-98, CH1641, Scrapie, TSE Prion, Update 2026
USA atypical Nor-98 Scrapie Update 2025 USA Scrapie typical and atypical USA
FY 2023, 16,646 from sheep and 8,726 from goats.
* There have been 491 NVSL confirmed positive animals (474 classical cases – 471 sheep and 3 goats) and ***> 19 Nor98- like cases since the beginning of RSSS. Figure 3 depicts RSSS collection sites in FY 2023.
https://www.aphis.usda.gov/sites/default/files/scrapie-annual-report.pdf
In 2023, APHIS collected samples from more than 26,000 sheep and goats for scrapie testing. Out of the total number of animals tested in 2023, no animals tested positive for classical scrapie and
***> one sheep tested positive for non-classical scrapie (Nor98-like)...
https://www.usda.gov/sites/default/files/documents/22-APHIS-2025-ExNotes.pdf
In 2022, APHIS collected samples from more than 23,000 sheep and goats for scrapie testing. Out of the total number of animals tested in 2022, no animals tested positive for classical scrapie and
***> one sheep tested positive for non-classical scrapie (Nor98-like).
https://www.usda.gov/sites/default/files/documents/23-2024-APHIS.pdf
In FY 2021, APHIS collected samples from more than 30,000 sheep and goats for scrapie testing. Out of the total number of samples processed and reported in FY 2021,
***> one sheep tested positive for classical scrapie and ***> one sheep tested positive for non-classical scrapie (Nor98-like).
https://www.usda.gov/sites/default/files/documents/23-2023-APHIS.pdf
In FY 2020, APHIS collected samples from 33,839 sheep and goats for scrapie testing. This number represents sample results reported by October 15, 2020 and is expected to slightly increase as the remaining results are processed and reported. No animals tested positive for classical scrapie.
***> Two sheep tested positive at slaughter for non-classical scrapie (Nor98-like).
https://www.usda.gov/sites/default/files/documents/22APHIS2022Notes.pdf
In FY 2019, APHIS collected samples from 34,730 sheep and goats for scrapie testing, ***> detecting 7 classical scrapie positive animals. Of these animals, five sheep and one goat were from a source flock in Pennsylvania that was found in August 2018, depopulated in October 2018, and tested for scrapie in November 2018. A second goat, which was from an Indiana herd, was sampled at slaughter in June 2019. The source flock completed a cleanup plan and was placed on a 5-year monitoring plan. The source herd of the positive Indiana goat no longer contained any exposed animals and was also placed on a 5-year monitoring plan. A trace-back investigation narrowed the goat’s birth herd to two possible herds. Animals in both herds tested negative for scrapie and were placed on 5-year monitoring plans. There were no classical scrapie cases detected in slaughter sheep in FY 2019.
***> Also in FY 2019, two sheep tested positive at slaughter for non-classical scrapie (Nor98-like) and were traced back to Colorado flocks.
https://www.usda.gov/sites/default/files/documents/20aphis2021notes.pdf
***> In FY 2018, APHIS collected samples from 43,625 sheep and goats for scrapie testing, detecting three positive (0.0068%) cases. These figures are based on sample submissions and testing completed by September 30, 2018. FY 2018 values are expected to change when testing is completed for all animals sampled in FY 2018.
***> In October 2017, a non-classical scrapie case was detected in a sheep from Virginia sampled at slaughter. As a result, the non- classical scrapie affected flock was placed on a 5-year monitoring plan.
https://www.usda.gov/sites/default/files/documents/20aphis2020notes.pdf
***> In FY 2016, the program identified one flock infected with classical scrapie and one infected with Nor98-like scrapie through slaughter surveillance, and two flocks infected with classical scrapie through on-farm surveillance.
***> An additional 10 sheep were confirmed with classical scrapie through testing of sheep depopulated from these infected flocks as part of flock clean-up activities conducted in FY 2016.
***> The Nor98-like scrapie affected flock will be placed on a 5-year monitoring plan.
https://www.usda.gov/sites/default/files/documents/20aphisexnotes2018.pdf
Atypical Nor-98 Scrapie TSE Prion USA State by State Update January 2021
Atypical Nor-98 Scrapie TSE Prion USA State by State Update January 2021
Nor98 cases Diagnosed in the US. To Date
Nor98 cases Diagnosed in the US.
Flock of Origin State FY
Wyoming 2007
Indiana 2007
Pennsylvania 2008
Oregon 2010
Ohio 2010
Pennsylvania 2010
Untraceable 2010
California 2011
Montana 2016
Utah 2017
Montana 2017
Virginia 2018
Colorado 2019
Colorado 2019
Wyoming 2020
Montana 2020
Pennsylvania 2021
Personal Communication from USDA et al Mon, Jan 4, 2021 11:37 am...terry
TUESDAY, SEPTEMBER 22, 2020
APHIS USDA MORE SCRAPIE ATYPICAL Nor-98 Confirmed USA September 15 2020
17 cases of the Nor98 in the USA to date, location, unknown...tss
17 Nor98-like cases since the beginning of RSSS.
https://www.aphis.usda.gov/animal_health/animal_diseases/scrapie/downloads/monthly_scrapie_report.pdf
17 Nor98-like cases since the beginning of RSSS. No animals have tested positive for classical scrapie in FY 2021.
https://www.aphis.usda.gov/animal_health/animal_diseases/scrapie/downloads/monthly_scrapie_report.pdf
TUESDAY, SEPTEMBER 22, 2020
APHIS USDA MORE SCRAPIE ATYPICAL Nor-98 Confirmed USA September 15 2020
https://scrapie-usa.blogspot.com/2020/09/aphis-usda-more-scrapie-atypical-nor-98.html
MONDAY, JULY 27, 2020
APHIS USDA Nor98-like scrapie was confirmed in a sheep sampled at slaughter in May 2020
https://nor-98.blogspot.com/2020/07/aphis-usda-nor98-like-scrapie-was.html
MONDAY, JULY 13, 2020
Efficient transmission of classical scrapie agent x124 by intralingual route to genetically susceptible sheep with a low dose inoculum
https://scrapie-usa.blogspot.com/2020/07/efficient-transmission-of-classical.html
*** Singeltary reply ; Molecular, Biochemical and Genetic Characteristics of BSE in Canada Singeltary reply ;
https://journals.plos.org/plosone/article/comment?id=10.1371/annotation/4f9be886-69fe-4c7c-922b-85b0ecbe6d53
Transmission of scrapie prions to primate after an extended silent incubation period
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=313160
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
Even if the prevailing view is that sporadic CJD is due to the spontaneous formation of CJD prions, it remains possible that its apparent sporadic nature may, at least in part, result from our limited capacity to identify an environmental origin.
https://www.nature.com/articles/srep11573
https://www.ars.usda.gov/research/publications/publication/?seqNo115=361032
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases.
==============
PRION 2015 CONFERENCE
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019500/
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-68961933-690X
WS-01: Prion diseases in animals and zoonotic potential
***Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice.
***Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
Title: Transmission of scrapie prions to primate after an extended silent incubation period)
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=313160
Comparing the Distribution of Ovine Classical Scrapie and Sporadic Creutzfeldt-Jakob Disease in Italy: Spatial and Temporal Associations (2002-2014)
Ru G1 ., Pocchiari M2 ., Bertolini S. 1, Pite L.1 , Puopolo M.2 , Ladogana A.2 , Perrotta M.G.3 , Meloni D 1 . (1) National reference center for the study and research on animal encephalopathies and comparative neuropathologies (CEA). Experimental Zooprophylactic Institute of Piemonte, Liguria and Valle d'Aosta, Torino, Italy.
(2) Department of Cellular Biology and Neuroscience, Istituto Superiore di Sanità, Roma, Italy. (3) Office 3 National center for the fight and emergency against animal diseases. Ministry of Health, Roma, Italy.
Aim: This study aims to investigate potential spatial and temporal associations between Creutzfeldt-Jakob disease (CJD) in humans (2010-2014) and ovine classical scrapie (CS) (2002- 2006) in Italy, serving as a proxy for exposure.
Materials and Methods: National data from prion disease surveillance in humans (sporadic CJD) and small ruminants (CS) in Italy were utilized. A descriptive geographic analysis was conducted for each disease individually. Subsequently, an ecological study was performed to compare the occurrence of both diseases at the district and regional levels. Standardized incidence ratios (SIR), adjusted for confounders, were calculated for CJD and CS by district and region, respectively, representing the outcome and proxy of exposure. Considering a possible long incubation period of CJD, two study periods were analysed: 2010-2014 for CJD and 2002-2006 for CS. Eight alternative linear regression models were developed using SIR in humans as the dependent variable and SIR in sheep as the independent variable. These models varied in the scale of SIR data (continuous vs. categorical), geographical level (district vs. region), and the potential past exposure of sheep in specific areas to a known source of infection (via a contaminated vaccine).
Results: The analysis of data at the district level revealed no significant association. However, when considering aggregated regional data, all four models consistently indicated a statistically significant positive association, suggesting a higher incidence of the disease in humans as the regional incidence of sheep scrapie increased.
Conclusions: While the results are intriguing, it is important to acknowledge the inherent limitations of ecological studies. Nevertheless, these findings provide valuable evidence to formulate a hypothesis regarding the zoonotic potential of classical scrapie. Further investigations are necessary, employing specific designs such as analytical epidemiology studies, to test this hypothesis effectively.
Funded by: Italian Ministry of Health Grant number: Realizzazione del programma epidemiologico finalizzato a dare evidenza del potenziale zoonotico delle TSE animali diverse dalla BSE. Prot. N. 0018730-17/07/2015-DGSAFCOD_UO-P
''Nevertheless, these findings provide valuable evidence to formulate a hypothesis regarding the zoonotic potential of classical scrapie. Further investigations are necessary, employing specific designs such as analytical epidemiology studies, to test this hypothesis effectively.''
Meeting-book-final-version prion 2023 Prion 2023 Congress Organizing Committee and the NeuroPrion Association, we invite you to join us for the International Conference Prion2023 from 16-20 October 2023 in Faro, Portugal.
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://web.archive.org/web/20250828201533/https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://www.researchgate.net/profile/Syed-Zahid-Shah/publication/378314391_Meeting-book-final-version_prion_2023/links/65d44dad28b7720cecdca95f/Meeting-book-final-version-prion-2023.pdf
=====
Transmission of Idiopathic human prion disease CJD MM1 to small ruminant mouse models (Tg338 and Tg501).
Enric Vidal1,2, Samanta Giler1,2, Montse Ordóñez1,2, Hasier Eraña3,4, Jorge M. Charco3,4, Guillermo Cantero1,2, Juan C. Espinosa5 , Juan M. Torres5 , Vincent Béringue6 , Martí Pumarola7 and Joaquín Castilla3,8,9
Aims: About 90% of Creutzfeldt-Jakob disease cases are classified as sporadic (sCJD), that is, occur infrequently, randomly and without a known cause. It is a fatal neurodegenerative disease with an incidence of 1-1.5 cases per million per year. Epidemiological studies have been so far unable to establish a causal relationship between sCJD and prion diseases in animals.
The zoonotic potential of sheep scrapie was demonstrated in 2014 (Cassard et al., Nature Communications) through inoculation of transgenic mice overexpressing the human prion protein with scrapie isolates. The resulting prion disease was indistinguishable from that occurring after sCJD inoculation in the same model and, while these results do not demonstrate that sCJD is caused by scrapie prions, they do show that the transmission barrier between ovine and human prions is not absolute. Our aim is to further assess this zoonotic risk.
Materials and methods: we have prepared inocula from 3 sCJD cases (MM1, MV2 and VV2) and 2 VPSPr cases (MM and MV) to verify if it is possible to recover the scrapie phenotype upon inoculation in Tg338 and Tg501 ovinized mouse models. Additionally, two different inocula gCJD (E200K) and GSS (A117V) have been also included in the bioassays as controls for classical and atypical genetic human prions, respectively.
Results: No evidence of transmission was found on a first passage in Tg338 nor Tg501 ovinized mice, but on second passage, 4/10 Tg338 mice succumbed to CJDMM1 (40% attack rate after 645 dpi) and 1/12Tg501 mice (519dpi, 10 still alive). The remaining 2nd passages are still ongoing. Conclusions: In this poster, the neuropathological features of the resulting strain are discussed.
Funded by: MINECO grant number AGL2017-88535-P and PID2021-1222010B-C22 and by Interreg POCTEFA grant number EFA148/16 (RedPRION)
''but on second passage, 4/10 Tg338 mice succumbed to CJDMM1 (40% attack rate after 645 dpi) and 1/12 Tg501 mice (519dpi, 10 still alive). The remaining 2nd passages are still ongoing. Conclusions: In this poster, the neuropathological features of the resulting strain are discussed.''
Meeting-book-final-version prion 2023 Prion 2023 Congress Organizing Committee and the NeuroPrion Association, we invite you to join us for the International Conference Prion2023 from 16-20 October 2023 in Faro, Portugal.
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://web.archive.org/web/20250828201533/https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
https://www.researchgate.net/profile/Syed-Zahid-Shah/publication/378314391_Meeting-book-final-version_prion_2023/links/65d44dad28b7720cecdca95f/Meeting-book-final-version-prion-2023.pdf
Dynamics of the natural transmission of bovine spongiform encephalopathy within an intensively managed sheep flock http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625529/ and I am reminded of the ch1641 strain that is like BSE ; ***> In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641.
Title: ASSESSMENT OF THE GENETIC RISK AND IMPACT OF LATERAL TRANSMISSION IN A VALINE-ASSOCIATED SCRAPIE OUTBREAK IN SHEEP
Author item.gif EVONIUK, J - NORTH DAKOTA STATE UNIV item.gif STOLTENOW, C - NORTH DAKOTA STATE UNIV item.gif O'Rourke, Katherine item.gif MOORE, B - NORTH DAKOTA STATE UNIV item.gif REDMER, D - NORTH DAKOTA STATE UNIV
Submitted to: American Journal of Veterinary Research Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/8/2005 Publication Date: 8/1/2005 Citation: Evoniuk, J.M., Stoltenow, C.L., O'Rourke, K.I., Moore, B.L., Redmer, D.A. 2005.
Assessment of the genetic risk and impact of lateral transmission in a valine-associated scrapie outbreak in sheep.
American Journal of Veterinary Research. 66(8):1-6. Interpretive
Summary: Scrapie is a fatal neurologic disease of sheep, endemic in the US but the subject of a vigorous eradication program. Scrapie is associated with accumulation of a misfolded form of the sheep prion protein. Control measures in an infected flock include removal of all genetically susceptible sheep. Susceptibility is controlled by naturally occurring differences in the prion protein, designated 171Q (susceptible) or 171R (generally resistant). The resistance of sheep with the 171R form of the gene occurs with one scrapie strain, the most US strain, but these sheep are not protected from the alternative strain, identified as valine associated scrapie. Anecdotal reports have shown that the strain probably occurs in the US but is relatively rare. In this publication, the presence of the valine associated strain was demonstrated through epidemiology and genetic analysis of a large flock of sheep. The study demonstrated that this scrapie strain can infect sheep as adults and is spread efficiently among related and unrelated sheep housed together during lambing seasons. The results suggest that the outbreak was due to the relatively high number of sheep with the susceptible form of the gene, probably introduced through the use of highly prolific rams carrying the gene. Further, transmission of the disease among adults, the prolonged incubation time, the unsuitability of some susceptible sheep to live animal testing, and susceptibility of sheep with the 171R gene suggest that removal of sheep with the genotype AVQR from infected flocks would be prudent.
Technical Abstract: Scrapie is a member of the heterogenous family of transmissible spongiform encephalopathies. Although these disorders appear to be related to misfolding of a host protein rather than an exogenous organism, two distinct disease phenotypes or strains are noted in sheep. Characterization of the scrapie strains in experimental and field settings in the United Kingdom and Europe have included differences in incubation time, survival rates, lateral transmission efficiency and most importantly, genetic susceptibility. Sheep of the prototype strain SSPB/1 are susceptible only if the PRNP (prion protein precursor gene) encodes valine (V) at codon 136; a polymorphism (encoding glutamine to arginine) at codon 171 apparently reduces disease prevalence but increases incubation time and limits tissue distribution to the brain. Sheep with the prototype valine-independent strain CH1641 are susceptible only if homozygous for glutamine (Q) at codon 171. In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641. The only genotype useful for strain discrimination is the relatively rare 136AV/171QR. In this study, a flock of sheep with a large number of infected sheep was analyzed. The presence of at least one V136 allele was identified in all but 2 sheep in the study, incubation times were very short in V136 homozygous sheep, probable lateral transmission was demonstrated in 15 sheep, and at least one AVQR sheep was identified. Therefore, this outbreak was probably due to a valine-associated (SSBP/1-like) strain and this report is the first full description of the epidemiology of this strain in US sheep. The high rate of lateral transmission and the susceptibility of 136AV/171QR sheep to scrapie suggest that genotyping for codon 136 may assist management decisions following a scrapie diagnosis and that it may be prudent to remove sheep of the 136AV/171QR genotype from infected flocks.
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=182469 4.2.9
A further hypothesis to explain the occurrence of BSE is the emergence or selection of a strain or strains of the scrapie agent pathogenic for cattle. Mutations of the scrapie agent. which can occur after a single passage in mice. have been well documented (9). This phenomenon cannot be dismissed for BSE. but given the form of the epidemic and the geographically widespread occurrence of BSE, such a hypothesis" would require the emergence of a mutant scrapie strain simultaneously in a large . number of sheep flocks, or cattle. throughout the country. Also. if it resulted "from a localised chance transmission of the scrapie strain from sheep to cattle giving rise , . to a mutant. a different pattern of disease would have been expected: its range would '. have increased with time. Thus the evidence from Britain is against the disease being due to a new strain of the agent, but we note that in the United States from 1984 to 1988 outbreaks of scrapie in sheep flocks are reported to have Increased markedly. now being nearly 3 times as high as during any previous period (18).
http://collections.europarchive.org/tna/20080102132706/http://www.bseinquiry.gov.uk/files/ib/ibd1/tab02.pdf
If the scrapie agent is generated from ovine DNA and thence causes disease in other species, then perhaps, bearing in mind the possible role of scrapie in CJD of humans (Davinpour et al, 1985), scrapie and not BSE should be the notifiable disease. ...
http://collections.europarchive.org/tna/20090505194948/http://bseinquiry.gov.uk/files/yb/1988/06/08004001.pdf
http://scrapie-usa.blogspot.com/2007/12/scrapie-hb-parry-seriously-yb886841.html
EVIDENCE OF SCRAPIE IN SHEEP AS A RESULT OF FOOD BORNE EXPOSURE
This is provided by the statistically significant increase in the incidence of sheep scrape from 1985, as determined from analyses of the submissions made to VI Centres, and from individual case and flock incident studies. ...
http://web.archive.org/web/20010305222246/www.bseinquiry.gov.uk/files/yb/1994/02/07002001.pdf
RISK OF BSE TO SHEEP VIA FEED
http://collections.europarchive.org/tna/20090114022605/http://www.bseinquiry.gov.uk/files/sc/seac31/tab01.pdf
OPII-1 Disease incidence and incubation period of BSE and CH1641 in sheep is associated with PrP gene polymorphisms.
Goldman WI, Hunter N., Benson G., Foster J. and Hope J. AFRC&MRC Neuropathogenesis Unit, Institute for Animal Health, West Mains Rd. Edinburgh EH9 3JF. U.K.
The relative survival periods of mice with different Sine genotype have long been used for scrapie strain typing. The PrP protein. a key molecule in the pathogenesis of scrapie and related diseases, is a product of the Sine locus and homologous proteins are also linked to disease-incidence loci in sheep and man. In sheep alleles of this locus (Sip) encode several PrP protein variants, of which one has been associated with short incubation periods of Cheviot sheep infected with SSBP/1 scrapie. Other isolates, i.e. BSE or CH1641. cause a different pattern of incubation periods and a lower disease incidence in the same flock of Cheviot sheep. Using transmission to sheep of known PrP genotype as our criterion for agent strain typing. we have found a link between BSE and CH1641, a C-group strain of scrapie. Disease susceptibility of sheep to these isolates is associated with different PrP genotypes compared to SSBP/1 scrapie.
OPII –2 Transmission of Bovine Spongiform Encephalopathy in sheep, goats and mice. Foster J., Hope J., McConnell I. and Fraser H. Institute for Animal Health, AFRC and MRC Neuropathogenesis Unit, Kings Buildings, West Mains Road, Edinburgh EH9 3JF
Bovine Spongiform Encephalopathy (BSE) has been transmitted in two lines of genetically selected sheep [differing in their susceptibilities to the SSBP/1 source of scrapie), and to goats by intracerebral injection and by oral dosing. Incubation periods in sheep for both routes of challenge ranged from 440-994 days. In goats this range was 506-1508days. Both routes of infection in sheep and goats were almost equally efficient. In mice, primary transmission of BSE identified a sinc-independant genetic control of incubation period. Also, intermediate passage of BSE in sheep or goats did not alter these primary transmission properties. Hamsters were susceptible to BSE only after intervening passage through mice.
https://web.archive.org/web/20060517075714/http://www.bseinquiry.gov.uk/files/mb/m09/tab11.pdf
***> “ we have found a link between BSE and CH1641, a C-group strain of scrapie.”
Docket No. APHIS-2007-0127 Scrapie in Sheep and Goats Terry Singeltary Sr. Submission Docket No. APHIS-2007-0127 Scrapie in Sheep and Goats
SUMMARY: We are reopening the comment period for our proposed rule that would revise completely the scrapie regulations, which concern the risk groups and categories established for individual animals and for flocks, the use of genetic testing as a means of assigning risk levels to animals, movement restrictions for animals found to be genetically less susceptible or resistant to scrapie, and recordkeeping requirements. This action will allow interested persons additional time to prepare and submit comments.DATES: The comment period for the proposed rule published on September 10, 2015 (80 FR 54660-54692) is reopened. We will consider all comments that we receive on or before December 9, 2015. ...
http://www.regulations.gov/#!documentDetail;D=APHIS-2007-0127-0001
http://www.gpo.gov/fdsys/pkg/FR-2015-11-16/html/2015-29179.htm
http://www.regulations.gov/#!docketDetail;D=APHIS-2007-0127
COMMENT SUBMISSION TERRY S. SINGELTARY SR.
WITH regards to Docket No. APHIS-2007-0127 Scrapie in Sheep and Goats, I kindly submit the following ;
The last major revision of the scrapie regulations occurred on August 21, 2001, when we published in the Federal Register(66 FR 43964, Docket No. 97-093-5) a final rule amending part 79 by imposing additional restrictions on the interstate movement of sheep and goats.<<<
Indeed, much science has changed about the Scrapie TSE prion, including more science linking Scrapie to humans. sadly, politics, industry, and trade, have not changed, and those usually trump sound science, as is the case with all Transmissible Spongiform Encephalopathy TSE Prion disease in livestock producing animals and the OIE. we can look no further at the legal trading of the Scrapie TSE prion both typical and atypical of all strains, and CWD all stains. With as much science of old, and now more new science to back this up, Scrapie of all types i.e. atypical and typical, BSE all strains, and CWD all strains, should be regulated in trade as BSE TSE PRION. In fact, I urge APHIS et al and the OIE, and all trading partners to take heed to the latest science on the TSE prion disease, all of them, and seriously reconsider the blatant disregards for human and animal health, all in the name of trade, with the continued relaxing of TSE Prion trade regulations through the ‘NEGLIGIBLE BSE RISK’ PROGRAM, which was set up to fail in the first place. If the world does not go back to the ‘BSE RISK ASSESSMENTS’, enhance, and or change that assessment process to include all TSE prion disease, i.e. ‘TSE RISK ASSESSMENT’, if we do not do this and if we continue this farce with OIE and the USDA et al, and the ‘NEGLIGIBLE BSE RISK’ PROGRAM, we will never eradicate the TSE prion aka mad cow type disease, they will continue to mutate and spread among species of human and animal origin, and they will continue to kill. ...
THURSDAY, SEPTEMBER 24, 2026
Looming Crisis U. S. Transmissible Spongiform Encephalopathy TSE Prion, in Cattle, Cervid, Sheep, Pigs, and Humans
https://transmissiblespongiformencephalopathy.blogspot.com/2026/09/looming-crisis-u-s-transmissible.html
https://prpsc.proboards.com/thread/246/looming-crisis-prion-cattle-cervid
Chronic wasting disease prions in cervids and wild pigs in North America Preliminary Outbreak Assessment DEFRA 26 January 2026 Department for Environment, Food and Rural Affairs
Preliminary Outbreak Assessment
Chronic wasting disease prions in cervids and wild pigs in North America
26 January 2026
Disease report
“They analysed over 300 brain and lymph node samples from 178 wild pigs living across Arkansas and Texas, USA…the researchers identified CWD prions in up to 37% of the lymph node samples and 15% of brain samples. The lowest detection rates were in the Texas samples (below 16%), matching the lower CWD prevalence in the state’s cervid population.”
https://assets.publishing.service.gov.uk/media/697a3b013c71d838df6bd413/CWD_Prions_in_Cervids_and_Wild_Pigs_in_North_America.pdf
Detection of Prions in Wild Pigs (Sus scrofa) from Areas with Reported Chronic Wasting Disease Cases, United State Volume 31, Number 1—January 2025
https://wwwnc.cdc.gov/eid/article/31/1/24-0401_article
Tuesday, June 9, 2026
Hazard identification for the risks to terrestrial animal health from the import of hay and straw, BSE, CWD, Scrapie, TSE, Prion
https://www.gov.uk/government/publications/hazard-identification-for-the-risks-to-terrestrial-animal-health-from-the-import-of-hay-and-straw/hazard-identification-for-the-risks-to-terrestrial-animal-health-from-the-import-of-hay-and-straw
https://defrauktseprp.blogspot.com/2026/06/hazard-identification-for-risks-to.html
Chronic Wasting Disease CWD TSE Prion, Economical, Environmental, Zoonotic, Risk Factors 2026
https://transmissiblespongiformencephalopathy.blogspot.com/2026/02/chronic-wasting-disease-cwd-tse-prion.html
***> USA Report, Scrapie, CWD, BSE, TSE, Cattle, Sheep, Pigs, Cervid, Humans, Zoonotic, 2026
April 2026
https://fdabse589.blogspot.com/2026/04/usa-report-scrapie-cwd-bse-tse-cattle.html
https://www.researchgate.net/publication/403956772_USA_Report_Scrapie_CWD_BSE_TSE_Cattle_Sheep_Pigs_Cervid_Humans_Zoonotic_2026
***> Cervid CWD TSE PrP Transmission to Humans, has it already happened and being masked as sporadic CJD, What if? July 2026 Review
https://chronic-wasting-disease.blogspot.com/2026/07/cervid-cwd-tse-prp-transmission-to.html
https://prpsc.proboards.com/thread/224/cervid-transmission-humans-july-review
WEDNESDAY, SEPTEMBER 2, 2026
A new chapter for CWRU’s Prion Center
https://prionunitusaupdate.blogspot.com/2026/09/a-new-chapter-for-cwrus-prion-center.html
https://prpsc.proboards.com/thread/239/new-chapter-cwru-prion-center
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. | 3:52 PM
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