Iceland Scrapie Report October 2025
Iceland Scrapie Report October 2025
I remember back a few decades ago, Iceland was boasting Scrapie Free. Not so anymore, even worse, seems they have let their guard down. Sadly, this could come back to haunt them…terry
Riðuveiki 2005-2024
Í reglugerð nr. 651/2001 um útrýmingu á riðuveiki og bætur vegna niðurskurðar segir að sýkt svæði sé svæði þar sem riðuveiki hefur verið staðfest sl. 20 ár. Riðuveiki hefur verið staðfest í sauðfé á eftirtöldum búum frá árinu 2005 til dagsins í dag.
Riðuveiki 2005 - 2024
Varnarhólf Sveitarfélag Búsnúmer Bær Ár Athugasemd
Miðfjarðarhólf Húnaþing vestra 1441001 Bergsstaðir 2023
Miðfjarðarhólf Húnaþing vestra 1441611 Syðri-Urriðaá 2023
Vatnsneshólf Húnaþing vestra 1444931 Neðra-Vatnshorn 2015
Vatnsneshólf Húnaþing vestra 1445141 Vatnshóll 2021
Húna- og Skagahólf Húnaþing vestra 1446371 Stórhóll 2023
Húna- og Skagahólf Húnavatnshreppur 1452831 Eiðsstaðir 2023
Húna og Skagahólf Húnaþing vestra 1446351 Sporður 2021
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460651 Syðra-Skörðugil 2021
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460351 Grófargil 2020
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460141 Álftagerði 2019
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460761 Vallanes 2018
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460001 Stóra-Gröf ytri 2016
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460171 Brautarholt 2016
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460821 Víðiholt 2015
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460751 Valagerði 2015
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1459701 Dæli 2009
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460141 Álftagerði 2008
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1460761 Vallanes 2007
Húna- og Skagahólf Húnaþing vestra 1446181 Kambhóll 2007
Húna- og Skagahólf Húnaþing vestra 1446371 Stórhóll 2006
Húna- og Skagahólf Sveitarfélagið Skagafjörður 1459981 Sólheimar 2006
Húna- og Skagahólf Húnavatnshreppur 1446701 Grímstunga 2005
Tröllaskagahólf Sveitarfélagið Skagafjörður 1464381 Hof 1 2020
Tröllaskagahólf Sveitarfélagið Skagafjörður 1464211 Syðri-Hofdalir 2020
Tröllaskagahólf Akrahreppur 1463421 Stóru-Akrar 2020
Tröllaskagahólf Akrahreppur 1463271 Minni-Akrar 2020
Tröllaskagahólf Akrahreppur 1462711 Grænamýri 2020
Tröllaskagahólf Dalvíkurbyggð 1520011 Urðir 2017 Möguleg enduruppkoma frá 2003
Tröllaskagahólf Dalvíkurbyggð 1519131 Dæli 2009
Suðurfjarðahólf Breiðdalshreppur 1589571 Gilsárstekkur 2005
Suðurfjarðahólf Breiðdalshreppur 1589571 Gilsárstekkur 2005 Möguleg enduruppkoma frá 1995
Austurvegur 64 • 800 Selfoss • Sími 530 4800 • www.mast.is • mast@mast.is Bls. 1/2
Hreppa-, Skeiða- og Flóahólf Flóahreppur 1663501 Hurðarbak 2010
Hreppa-, Skeiða- og Flóahólf Hrunamannahreppur 1667631 Hrafnkelsstaðir 2007 Möguleg enduruppkoma frá 2001
Hreppa-, Skeiða- og Flóahólf Flóahreppur 1654831 Gerðar 2006
Hreppa-, Skeiða- og Flóahólf Flóahreppur 1655001 Syðri-Völlur 2006
Afbrigðileg riðuveiki (Nor98) hefur verið staðfest í sauðfé á eftirtöldum búum frá árinu 2004 til dagsins í dag. Erlendar rannsóknir hafa sýnt að Nor98 er ekki smitandi líkt og hefðbundin riða og það er álit Matvælastofnunar að ekki sé ástæða til að skera niður þegar Nor98 tilfelli greinast eins og gert er þegar um hefðbundna riðu er að ræða. Þó er vöktun aukin á viðkomandi bæjum og nágrannabæjum.
Afbrigðileg riða - Nor98 árin 2005 - 2024
Varnarhólf Sveitarfélag Búsnúmer Bær Ár Athugasemd
Vesturlandshólf Borgarbyggð 1347311 Höfði 2023 Nor98
Dalahólf Húnaþing vestra 1421851 Bær 2 2023 Nor98
Miðfjarðarhólf Húnaþing vestra 1440201 Brautarholt 2008 Nor98
Vatnsneshólf Húnaþing vestra 1444961 Sauðá 2024 Nor98
Húna- og Skagahólf Húnavatnshreppur 1453191 Stekkjardalur 2024 Nor98
Húna- og Skagahólf Húnavatnshreppur 1453401 Bergsstaðir 2013 Nor98
Tröllaskagahólf Akrahreppur 1463631 Þverá II 2021 Nor98
Héraðshólf Fljótsdalshérað 1569201 Merki 2011 Nor98
Suðurfjarðahólf Djúpavogshreppur 1591121 Kelduskógar 2015 Nor98
Suðurfjarðahólf Djúpavogshreppur 1591131 Kross 2013 Nor98
Hreppa-, Skeiða- og Flóahólf Hrunamannahreppur 1668281 Skollagróf 2007 Nor98
Samkvæmt reglugerð nr. 651/2001 um útrýmingu á riðuveiki og bætur vegna niðurskurðar er svæði sýkt í 20 ár frá því að riðuveiki greinist. Hér má sjá hvenær hólfin losna undan höftum riðuskilgreiningar, að því gefnu að engin ný tilfelli komi upp.
Aflétting riðuhafta í hólfum
Varnarhólf Sýkt svæði Síðasta riðutilfelli Riðutímabili lýkur
Landnámshólf Sveitarfélögin Ölfus, Hveragerði, Árborg og Grafningur í Grímsnes- og Grafningshreppi 2003 31. desember 2023
Vatnsneshólf Allt hólfið 2021 31. desember 2041
Húna- og Skagahólf Allt hólfið 2021 31. desember 2041
Tröllaskagahólf Allt hólfið 2020 31. desember 2040
Suðurfjarðarhólf Allt hólfið 2005 31. desember 2025
Hreppa-, Skeiða- og Flóahólf Allt hólfið 2010 31. desember 2030
Biskupstungnahólf Allt hólfið 2004 31. desember 2024
Listi uppfærður 30.1.2025
Austurvegur 64 • 800 Selfoss • Sími 530 4800 • www.mast.is • mast@mast.is Bls. 2/2
News from Iceland
Pleased to keep part of their flock
Scrapie was detected at the farm Kirkjuhóll in Skagafjörður last week. The diagnosis is always a major blow, and it is clear that much work now awaits the farmers there. The farmers say it is a comfort that they can keep some of their flock.
Darren Adam
8. October 2025 - 06:16 GMT
For decades, scrapie has caused serious difficulties for farmers across the country, and at the end of last week, it was confirmed in a sheep at Kirkjuhóll farm, near Varmahlíð.
In recent years, targeted work has been underway to breed the so-called ARR gene into the sheep population; this gene was first found in a sheep in Reyðarfjörður in 2022.
Farmers Aron Pétursson and Guðmunda Steina Jónsdóttir say it is painful to see a large part of their flock go but take comfort in being allowed to keep some of their animals.
Guðmunda says she is not aware of scrapie having previously been detected in Iceland on a farm where sheep with the protective genotype were already present.
The gene is recognized as providing resistance to scrapie, meaning that sheep carrying it cannot become infected with the disease. It is, however, not the only gene that offers protection.
Over the past few years, the couple have been breeding for resistance to scrapie and now own around 130 ewes with genotypes considered protective. This makes a big difference for Aron and Guðmunda, as it is now permitted to keep animals with scrapie-resistant genotypes and those believed to carry such genes.
Aron says it never crossed their minds to give up sheep farming, but the situation might have been different had they not been allowed to keep part of their flock. They hope their case will help researchers study how effectively the ARR gene works.
Aron and Guðmunda say it is a blessing to live in a supportive community when something like this happens. Aron says other farmers have shown them great solidarity, although they are also anxious about the situation.
But everyone is ready to help us - people have already offered us breeding rams, because we aim to keep only sheep with such resistant genetics from now on.
EFSA atypical Scrapie
***> AS is considered more likely (subjective probability range 50–66%) that AS is a non-contagious, rather than a contagious, disease.
SNIP...SEE;
THURSDAY, JULY 8, 2021
EFSA Scientific report on the analysis of the 2‐year compulsory intensified monitoring of atypical scrapie
***> AS is considered more likely (subjective probability range 50–66%) that AS is a non-contagious, rather than a contagious, disease.
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.
=====
Abstract for Prion 2023
Title: Transmission of atypical BSE: a possible origin of Classical BSE in cattle
Authors: Sandor Dudas1, Samuel James Sharpe1, Kristina Santiago-Mateo1, Stefanie Czub1, Waqas Tahir1,2, *
Affiliation: 1National and WOAH reference Laboratory for Bovine Spongiform Encephalopathy, Canadian Food inspection Agency, Lethbridge Laboratory, Lethbridge, Canada. 2Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada.
*Corresponding and Presenting Author: waqas.tahir@inspection.gc.ca
Background: Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disease of cattle and is categorized into classical and atypical forms. Classical BSE (CBSE) is linked to the consumption of BSE contaminated feed whereas atypical BSE is considered to be spontaneous in origin. The potential for oral transmission of atypical BSE is yet to be clearly defined.
Aims: To assess the oral transmissibility of atypical BSE (H and L type) in cattle. Should transmission be successful, determine the biochemical characteristics and distribution of PrPSc in the challenge cattle.
Material and Methods: For oral transmission, calves were fed with 100 g of either H (n=3) or L BSE (n=3) positive brain material. Two years post challenge, 1 calf from each of the H and L BSE challenge groups exhibited behavioural signs and were euthanized. Various brain regions of both animals were tested by traditional and novel prion detection methods with inconclusive results. To detect infectivity, brain homogenates from these oral challenge animals (P1) were injected intra-cranially (IC) into steer calves. Upon clinical signs of BSE, 3/4 of IC challenged steer calves were euthanized and tested for PrPSc with ELISA, immunohistochemistry and immunoblot.
Results: After 6 years of incubation, 3/4 animals (2/2 steers IC challenged with brain from P1 L-BSE oral challenge and 1/2 steer IC challenged with brain from P1 H-BSE oral challenge) developed clinical disease. Analysis of these animals revealed high levels of PrPSc in their brains, having biochemical properties similar to that of PrPSc in C-BSE.
Conclusion: These results demonstrate the oral transmission potential of atypical BSE in cattle. Surprisingly, regardless of which atypical type of BSE was used for P1 oral challenge, PrPSc in the P2 animals acquired biochemical characteristics similar to that of PrPSc in C-BSE, suggesting atypical BSE as a possible origin of C-BSE in UK.
Presentation Type: Oral Presentation
Funded by: CFIA, Health Canada, Alberta Livestock and Meat Agency, Alberta Prion
Research Institute
Grant Number: ALMA/APRI: 201400006, HC 414250
Abstract for Prion 2023
Acknowledgement: TSE unit NCAD, Lethbridge (Jianmin Yang, Sarah Bogart, Rachana Muley, Yuanmu Fang, Keri Colwell, Renee Anderson, John Gray, Rakhi Katoch) (CFIA, Canada), Dr. Catherine Graham (NSDA, Canada), Dr. Michel Levy (UCVM, Canada), Dr. Martin Groschup (FLI, Germany), Dr. Christine Fast (FLI, Germany), Dr. Bob Hills (Health Canada, Canada)
SUNDAY, APRIL 06, 2025
Failure to prevent classical scrapie after repeated decontamination of a barn Failure to prevent classical scrapie after repeated decontamination of a barn
Published: 25 March 2025
Timm Konold, John Spiropoulos, Peter Bellerby & Hugh A Simmons BMC Research Notes volume 18, Article number: 126 (2025) Cite this article
Prions, the causative agent of scrapie in sheep, are extremely resistant to disinfection and can remain biologically active for years, which makes it challenging to prevent re-infection of susceptible animals on farms after a scrapie outbreak. The present study investigated the effectiveness of disinfection of a barn that previously housed scrapie-affected sheep as part of the husbandry of scrapie infected sheep on the farm. The barn was decontaminated with sodium hypochlorite for four times the recommended exposure time. Two cohorts, consisting of 25 and 21 sheep, with susceptible prion protein genotypes (VRQ/VRQ), born 2 years apart, were housed in the barn and infection monitored by examination of rectal biopsies.
Results
One sheep from the first cohort and four from the second were found to be infected from 775 (first cohort) and 550 days (second cohort) post exposure. It is concluded that decontamination with sodium hypochlorite at the recommended concentration and longer exposure time did not prevent re-infection of susceptible sheep. Disinfection of contaminated premises to eradicate scrapie continues to be a challenge.
Snip…
In conclusion, this study has shown that repeated disinfection with sodium hypochlorite, even using extended decontamination times, did not prevent re-infection so that there is a risk of re-infection if sheep with susceptible genotypes are re-introduced. It is not known whether decontamination was ineffective or recontamination occurred from various sources.
I remember what “deep throat” told me about Scrapie back around 2001, this was right after my Mom died from confirmed hvCJD around Christmas 1997, a few years later, when I was corresponding with officials in England, early BSE Inquiry days, and I never forgot, and it seems it’s come to pass;
***> Confidential!!!!
***> As early as 1992-3 there had been long studies conducted on small pastures containing scrapie infected sheep at the sheep research station associated with the Neuropathogenesis Unit in Edinburgh, Scotland. Whether these are documented...I don't know. But personal recounts both heard and recorded in a daily journal indicate that leaving the pastures free and replacing the topsoil completely at least 2 feet of thickness each year for SEVEN years....and then when very clean (proven scrapie free) sheep were placed on these small pastures.... the new sheep also broke out with scrapie and passed it to offspring. I am not sure that TSE contaminated ground could ever be free of the agent!! A very frightening revelation!!!
---end personal email---end...tss
and so it seems…so, this is what we leave our children and grandchildren?
Rapid recontamination of a farm building occurs after attempted prion removal
First published: 19 January 2019 https://doi.org/10.1136/vr.105054
The data illustrates the difficulty in decontaminating farm buildings from scrapie, and demonstrates the likely contribution of farm dust to the recontamination of these environments to levels that are capable of causing disease.
snip...
This study clearly demonstrates the difficulty in removing scrapie infectivity from the farm environment. Practical and effective prion decontamination methods are still urgently required for decontamination of scrapie infectivity from farms that have had cases of scrapie and this is particularly relevant for scrapie positive goatherds, which currently have limited genetic resistance to scrapie within commercial breeds.24 This is very likely to have parallels with control efforts for CWD in cervids.
***>This is very likely to have parallels with control efforts for CWD in cervids.
Front. Vet. Sci., 14 September 2015 | https://doi.org/10.3389/fvets.2015.00032
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination.
"Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation."
15 YEARS!
Detection of prions in soils contaminated by multiple routes
Results: We are able to detect prion seeding activity at multiple types of environmental hotspots, including carcass sites, contaminated captive facilities, and scrapes (i.e. urine and saliva). Differences in relative prion concentration vary depending on the nature and source of the contamination. Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation.
Conclusions: Detection of prions in the environment is of the utmost importance for controlling chronic wasting disease spread. Here, we have demonstrated a viable method for detection of prions in complex environmental matrices. However, it is quite likely that this method underestimates the total infectious prion load in a contaminated sample, due to incomplete recovery of infectious prions. Further refinements are necessary for accurate quantification of prions in such samples, and to account for the intrinsic heterogeneities found in the broader environment.
Funded by: Wisconsin Department of Natural Resources
Prion 2023 Abstracts
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.''
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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.''
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
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 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.
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were exposed to the infectious agents only by their nonforced consumption of known infectious tissues. The asymptomatic incubation period in the one monkey exposed to the virus of kuru was 36 months; that in the two monkeys exposed to the virus of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively. Careful physical examination of the buccal cavities of all of the monkeys failed to reveal signs or oral lesions. One additional monkey similarly exposed to kuru has remained asymptomatic during the 39 months that it has been under observation.
snip...
The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie by natural feeding to squirrel monkeys that we have reported provides further grounds for concern that scrapie-infected meat may occasionally give rise in humans to Creutzfeldt-Jakob disease.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
Recently the question has again been brought up as to whether scrapie is transmissible to man. This has followed reports that the disease has been transmitted to primates. One particularly lurid speculation (Gajdusek 1977) conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible encephalopathy of mink are varieties of a single "virus". The U.S. Department of Agriculture concluded that it could "no longer justify or permit scrapie-blood line and scrapie-exposed sheep and goats to be processed for human or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by the finding that some strains of scrapie produce lesions identical to the once which characterise the human dementias"
Whether true or not. the hypothesis that these agents might be transmissible to man raises two considerations. First, the safety of laboratory personnel requires prompt attention. Second, action such as the "scorched meat" policy of USDA makes the solution of the acrapie problem urgent if the sheep industry is not to suffer grievously.
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76/10.12/4.6
Nature. 1972 Mar 10;236(5341):73-4.
Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis).
Gibbs CJ Jr, Gajdusek DC.
Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0
Transmission of Scrapie to the Cynomolgus Monkey (Macaca fascicularis)
C. J. GIBBS jun. & D. C. GAJDUSEK
National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland
SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey (Macaca fascicularis) with an incubation period of more than 5 yr from the time of intracerebral inoculation of scrapie-infected mouse brain. The animal developed a chronic central nervous system degeneration, with ataxia, tremor and myoclonus with associated severe scrapie-like pathology of intensive astroglial hypertrophy and proliferation, neuronal vacuolation and status spongiosus of grey matter. The strain of scrapie virus used was the eighth passage in Swiss mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton, Berkshire).
***> “The WOAH and APHIS determined that it is not a disease of trade concern.” <***
Remember that!…terry
Classical BSE emergence from Nor98/atypical scrapie: Unraveling the shift vs. selection dichotomy in the prion field
Sara Canoyra https://orcid.org/0000-0001-6371-8122, Alba Marín-Moreno https://orcid.org/0000-0002-4023-6398, Juan Carlos Espinosa https://orcid.org/0000-0002-6719-9902, +5 , and Juan María Torres https://orcid.org/0000-0003-0443-9232jmtorres@inia.csic.esAuthors Info & Affiliations Edited by Byron Caughey, National Institute of Allergy and Infectious Diseases (National Institutes of Health), Hamilton, MT; received January 17, 2025; accepted June 7, 2025 by Editorial Board Member Lila M. Gierasch
July 15, 2025 122 (29) e2501104122 https://doi.org/10.1073/pnas.2501104122
Significance
Classical bovine spongiform encephalopathy (c-BSE) is a fatal cattle prion disease transmissible to humans as variant Creutzfeldt–Jakob Disease (vCJD). Understanding how c-BSE emerges is crucial for preventing future outbreaks and protecting public health. Two main hypotheses explain prion adaptation during cross-species transmission: “conformational shift or deformed templating,” where the species barrier forces a change to a different pathological prion protein, and “conformational selection,” where the species barrier filters preexisting conformers. Our results demonstrate that the conformational shift mechanism explains the emergence of c-BSE when Nor98/atypical scrapie (AS) is transmitted to cattle. This is significant because AS, found in sheep and goats worldwide, can convert to c-BSE. Preventing AS from entering the food chain is crucial to reduce c-BSE/vCJD risks.
Abstract
Prion diseases can manifest with distinct phenotypes in a single species, a phenomenon known as prion strains. Upon cross-species transmission, alterations in the disease phenotype can occur, interpreted as the emergence of a new strain. Two main and non–mutually exclusive evolutionary hypotheses have been proposed to explain this phenomenon: the “conformational shift” or “deformed templating” and the “conformational selection.” The conformational shift hypothesis proposes that the introduction of a new host prion protein (PrPC) forces a change in the conformation of the pathological prion protein (PrPSc), causing the new prion strain emergence. On the contrary, the conformational selection model postulates that prion isolates are a conglomerate of PrPSc conformations with relative distribution frequencies, wherein the species barrier acts as a filter selecting the one fittest for the new species environment. Previous studies reported the emergence of the classical bovine spongiform encephalopathy agent (c-BSE) upon transmission of Nor98/atypical scrapie (AS) onto a bovine PrP. This study investigates the evolutionary dichotomy of this c-BSE emergence by using prion strain thermostability combined with protein misfolding cyclic amplification to distinguish between both strains. Our results suggest that the conformational shift could be the principal mechanism responsible for the c-BSE emergence. Furthermore, the selection model was dismissed as the key mechanism based on the analysis of an artificial c-BSE and AS mixture. The ability of the AS conformers to shift conformation to a c-BSE one supports the hypothesis that the epidemic c-BSE prion may have originated from the transmission of AS in cattle.
Published: 04 October 2023
Detection of classical BSE prions in asymptomatic cows after inoculation with atypical/Nor98 scrapie
Abstract The emergence of bovine spongiform encephalopathy (BSE) prions from atypical scrapie has been recently observed upon experimental transmission to rodent and swine models. This study aimed to assess whether the inoculation of atypical scrapie could induce BSE-like disease in cattle. Four calves were intracerebrally challenged with atypical scrapie. Animals were euthanized without clinical signs of prion disease and tested negative for PrPSc accumulation by immunohistochemistry and western blotting. However, an emergence of BSE-like prion seeding activity was detected during in vitro propagation of brain samples from the inoculated animals. These findings suggest that atypical scrapie may represent a potential source of BSE infection in cattle.
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However, in conclusion, our findings show that the propagation of atypical scrapie in cattle leads to the emergence of BSE-like seeding activity. This is a concerning issue with far-reaching implications for public health and food safety. The possibility of interspecies transmission of prion diseases and the emergence of new prion strains highlight the critical need for continued surveillance and monitoring of these diseases in both animal and human populations. Early detection of prion diseases is crucial, and highly sensitive detection techniques such as PMCA can play an important role in this regard.
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.
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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.
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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.
35. Detection of Pathological Prion Protein in Milk Samples from Scrapie Naturally Infected Sheep by Real-Time Quaking-Induced Conversion assay
Alessandra Favolea, Valentina Campiaa, Serena Ravettaa, Davide Pintusb, Ciriaco Ligiosb, Romolo Nonnoc, Cristina Casalonea, Maria Caramellia, Cristiano Coronaa, Maria Mazzaa and Pier Luigi Acutisa
aNational TSE Surveillance Center, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, Turin, Italy; bIstituto Zooprofilattico Sperimentale della Sardegna, Sassari, Italy; cIstituto Superiore Sanità, Roma, Italy.
Aims: One of the major challenges in managing TSEs in animals is the lack of validated and sensitive intra-vitam assays. The high sensitivity of Real-Time Quaking-Induced Conversion (RT-QuIC) in amplifying PrPSc across various biological matrices suggests that it is an ideal method for this purpose. However, it remains ineffective on blood and impractical for cerebrospinal fluid (CSF) due to collection challenges at the flock level. Given the established involvement of milk in prion transmission, the study aimed to develop RT-QuIC conditions for the detection of PrPSc in milk obtained from naturally Scrapie-infected sheep.
Materials and Methods: ~50 ml of milk samples were collected from lactating sheep belonging to an Italian outbreak of classical Scrapie. TSE diagnosis was performed on obex by rapid test (IDEXX HerdChek BSE-scrapie antigen test kit EIA rapid test) and western blot. Sheep brain tissues affected by Scrapie resuspended at 10% (weight/volume) in homogenization buffer were used for preliminary spiking experiments in milk collected from uninfected scrapie sheep and as positive controls in RT-QuIC reactions. Milk samples were added with an equal volume of isopropanol/butanol (1:1 v/v) and centrifuged at 13,000 g for 30 min. Supernatants were discarded and the pellets were suspended in 0.1% of SDS/PBS solution or in lysis buffer (N-lauroyl sarcosine) and assayed neat or diluted from 1:10 to 1:1000. RT-QuIC tests were performed according to the protocol previously reported by Favole et al (2019).
Results:The analysis demonstrated that two rPrP substrates (rHa 90–231 and BV 23–231) can sensitively detect Scrapie PrPSc spiked in diluted milk. Specifically, rHa PrP 90–231 exhibited rapid reactions with lag phases comparable to reactions seeded with Scrapie brain homogenates. Furthermore, the precipitation protocol using an isopropanol/butanol solution enabled the detection of seeding activity associated with the presence of PrPSc in RT-QuIC tests, with a latency phase of 20–30 hours when applied to 10 mL of individual milk samples collected from 2/2 Scrapie naturally infected sheep.
Conclusions: These data confirm the secretion of prions within milk during the early stages of disease progression and a role for milk in prion transmission. Furthermore, the application of RT-QuIC to milk samples offers a non-invasive methodology to detect scrapie during preclinical/subclinical disease.
Funding: This work was supported by grants from the Italian Ministry of Health to Pier Luigi Acutis
Grant number: RF-2019-12369570
Acknowledgement
Component 6: Transmissible Spongiform Encephalopathies
Sheep scrapie agent can infect white-tailed deer after oronasal exposure.
Virus and Prion Disease Research Unit, National Animal Disease Center, Ames, Iowa
The origin of chronic wasting disease (CWD) is not known, but it has many similarities to the sheep prion disease called scrapie. It has long been hypothesized that CWD arose through transmission of sheep scrapie to deer. ARS researchers in Ames, Iowa, conducted research to determine if scrapie derived from sheep could be transmitted to white-tailed deer. The deer inoculated with sheep scrapie developed clinical signs and the abnormal prion protein could be detected in a wide range of tissues. These results indicate that deer may be susceptible to sheep scrapie if exposed to the disease in natural or agricultural settings. In addition, several strong similarities between CWD in white-tailed deer and the experimental cases of scrapie in white-tailed deer suggests that it would be difficult to distinguish scrapie from CWD in deer or identify scrapie if a case occurs. This information should be considered by deer farmers for keeping their herds free from prion diseases.
See updated studies on Atypical Scrapie AS
Atypical Scrapie
Updates on the WOAH activities in the field of TSEs
Natalie MOYEN Disease Status Officer
Status Department
May 14 th , 2024
2
Outline 1. Revised BSE standards (Terrestrial Code)
a) b) Transition process: where are we?
Official recognition of BSE risk status
i. Members/zones recognised as having a negligible or controlled BSE risk status
ii. New applications
iii. Annual reconfirmations
2. Revision of Scrapie standards (Terrestrial Code
Scrapie, BSE, and CWD Update October 2025
TUESDAY, SEPTEMBER 30, 2025
USDA National Scrapie Program History and Bovine Spongiform Encephalopathy BSE TSE Update 2025
TUESDAY, SEPTEMBER 30, 2025
USDA National Scrapie Program History and Bovine Spongiform Encephalopathy BSE TSE Update 2025
TUESDAY, SEPTEMBER 30, 2025
USDA EXPLANATORY NOTES ANIMAL AND PLANT HEALTH INSPECTION SERVICE 2025-2014 CHRONIC WASTING DISEASE CWD TSE CERVID
Terry Singeltary Sr.
posted by Terry S. Singeltary Sr. | 12:37 PM
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