Consultation: Draft VKM order on zoonotic potential in scrapie Singeltary Submission
Terry Singeltary flounder9@verizon.net
| To | julie.enebo.grimstad@mattilsynet.no julie.enebo.grimstad@mattilsynet.no |
| Cc | Kristin.Ruud.Alvseike@mattilsynet.no Kristin.Ruud.Alvseike@mattilsynet.no, pressevakt@mattilsynet.no pressevakt@mattilsynet.no, vkm@vkm.no vkm@vkm.no, danica.grahek-ogden@vkm.no danica.grahek-ogden@vkm.no |
Consultation: Draft VKM order on zoonotic potential in scrapie Singeltary Submission
Consultation: Draft VKM order on zoonotic potential in scrapie
Published 20.04.2021 Last changed 21.04.2021 Print
The prion disease scrapie has been detected in several types of deer in Norway. The Norwegian Food Safety Authority has previously asked the Scientific Committee for Food and the Environment (VKM) to assess the zoonotic potential of scrapie. Human disease caused by scrapie has never been proven, and this danger is considered to be very low. However, it may be relevant to introduce precautionary measures, and they must be based on current knowledge.
The Norwegian Food Safety Authority therefore asks VKM to issue a statement with updated knowledge about the zoonotic potential of scrapie when handling slaughter and consumption of meat.
The progress of the work is shown by the timeline below, and the black box shows where we are in the process.
Timeline for this work:
Greetings Norway et al, i kindly wish to submit the following, i submitted this to the online submission form as well...kindest regards, terry
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
PLEASE NOTE;
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
Olivier Andreoletti, INRA Research Director, Institut National de la Recherche Agronomique (INRA) – École Nationale Vétérinaire de Toulouse (ENVT), invited speaker, presented the results of two recently published scientific articles of interest, of which he is co-author: ‘Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice’ (MarinMoreno et al., 2020) and ‘The emergence of classical BSE from atypical/Nor98 scrapie’ (Huor et al., 2019).
In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.
WEDNESDAY, JUNE 10, 2020
Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice
Atypical BSE prions showed a modification in their zoonotic ability after adaptation to sheep-PrP producing agents able to infect TgMet129 and TgVal129, bearing features that make them indistinguishable of sporadic Creutzfeldt-Jakob disease prions.
our results clearly indicate that atypical BSE adaptation to an ovine-PrP sequence could modify the prion agent to potentially infect humans, showing strain features indistinguishable from those of classic sCJD prions, even though they might or might not be different agents.
However, the expanding range of TSE agents displaying the capacity to transmit in human-PrP–expressing hosts warrants the continuation of the ban on meat and bone meal recycling and underscores the ongoing need for active surveillance
***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.
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases).
Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** 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.
We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
===============
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
==============
***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.
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
Taylor & Francis
Prion 2016 Animal Prion Disease Workshop Abstracts
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.
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.
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.
snip...
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).
***> CWD AND SCRAPIE TRANSMITS BY ORAL ROUTES TO PIGS, PRICE OF TSE PRION POKER GOES UP!
2021 Transmissible Spongiform Encephalopathy TSE Prion End of Year Report 2020
CJD FOUNDATION VIRTUAL CONFERENCE CJD Foundation Research Grant Recipient Reports Panel 2 Nov 3, 2020
zoonotic potential of PMCA-adapted CWD PrP 96SS inoculum
4 different CWD strains, and these 4 strains have different potential to induce any folding of the human prion protein.
***> PIGS, WILD BOAR, CWD <***
***> POPULATIONS OF WILD BOARS IN THE UNITED STATES INCREASING SUPSTANTUALLY AND IN MANY AREAS WE CAN SEE A HIGH DENSITY OF WILD BOARS AND HIGH INCIDENT OF CHRONIC WASTING DISEASE
HYPOTHOSIS AND SPECIFIC AIMS
HYPOTHOSIS
BSE, SCRAPIE, AND CWD, EXPOSED DOMESTIC PIGS ACCUMULATE DIFFERENT QUANTITIES AND STRAINS OF PRIONS IN PERIPHERAL TISSUES, EACH ONE OF THEM WITH PARTICULAR ZOONOTIC POTENTIALS
Final Report – CJD Foundation Grant Program A.
Project Title: Systematic evaluation of the zoonotic potential of different CWD isolates. Principal Investigator: Rodrigo Morales, PhD.
Systematic evaluation of the zoonotic potential of different CWD isolates. Rodrigo Morales, PhD Assistant Professor Protein Misfolding Disorders lab Mitchell Center for Alzheimer’s disease and Related Brain Disorders Department of Neurology University of Texas Health Science Center at Houston Washington DC. July 14th, 2018
Conclusions and Future Directions • We have developed a highly sensitive and specific CWD-PMCA platform to be used as a diagnostic tool. • Current PMCA set up allow us to mimic relevant prion inter-species transmission events. • Polymorphic changes at position 96 of the prion protein apparently alter strain properties and, consequently, the zoonotic potential of CWD isolates. • Inter-species and inter-polymorphic PrPC → PrPSc conversions further increase the spectrum of CWD isolates possibly present in nature. • CWD prions generated in 96SS PrPC substrate apparently have greater inter-species transmission potentials. • Future experiments will explore the zoonotic potential of CWD prions along different adaptation scenarios, including inter-species and inter-polymorphic.
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research
Title: Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease
Author item MOORE, SARAH - Orise Fellow item Kunkle, Robert item KONDRU, NAVEEN - Iowa State University item MANNE, SIREESHA - Iowa State University item SMITH, JODI - Iowa State University item KANTHASAMY, ANUMANTHA - Iowa State University item WEST GREENLEE, M - Iowa State University item Greenlee, Justin Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 3/15/2017 Publication Date: N/A Citation: N/A Interpretive Summary:
Technical Abstract: Aims: Chronic wasting disease (CWD) is a naturally-occurring, fatal neurodegenerative disease of cervids. We previously demonstrated that disease-associated prion protein (PrPSc) can be detected in the brain and retina from pigs challenged intracranially or orally with the CWD agent. In that study, neurological signs consistent with prion disease were observed only in one pig: an intracranially challenged pig that was euthanized at 64 months post-challenge. The purpose of this study was to use an antigen-capture immunoassay (EIA) and real-time quaking-induced conversion (QuIC) to determine whether PrPSc is present in lymphoid tissues from pigs challenged with the CWD agent.
Methods: At two months of age, crossbred pigs were challenged by the intracranial route (n=20), oral route (n=19), or were left unchallenged (n=9). At approximately 6 months of age, the time at which commercial pigs reach market weight, half of the pigs in each group were culled (<6 month challenge groups). The remaining pigs (>6 month challenge groups) were allowed to incubate for up to 73 months post challenge (mpc). The retropharyngeal lymph node (RPLN) was screened for the presence of PrPSc by EIA and immunohistochemistry (IHC). The RPLN, palatine tonsil, and mesenteric lymph node (MLN) from 6-7 pigs per challenge group were also tested using EIA and QuIC.
Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 month group was positive by EIA. PrPSc was detected by QuIC in at least one of the lymphoid tissues examined in 5/6 pigs in the intracranial <6 months group, 6/7 intracranial >6 months group, 5/6 pigs in the oral <6 months group, and 4/6 oral >6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%).
Conclusions: This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge. CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period. This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease. Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies Location: Virus and Prion Research
Title: The agent of chronic wasting disease from pigs is infectious in transgenic mice expressing human PRNP
Author item MOORE, S - Orise Fellow item Kokemuller, Robyn item WEST-GREENLEE, M - Iowa State University item BALKEMA-BUSCHMANN, ANNE - Friedrich-Loeffler-institut item GROSCHUP, MARTIN - Friedrich-Loeffler-institut item Greenlee, Justin Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 5/10/2018 Publication Date: 5/22/2018 Citation: Moore, S.J., Kokemuller, R.D., West-Greenlee, M.H., Balkema-Buschmann, A., Groschup, M.H., Greenlee, J.J. 2018. The agent of chronic wasting disease from pigs is infectious in transgenic mice expressing human PRNP. Prion 2018, Santiago de Compostela, Spain, May 22-25, 2018. Paper No. WA15, page 44.
Interpretive Summary:
Technical Abstract: We have previously shown that the chronic wasting disease (CWD) agent from white-tailed deer can be transmitted to domestic pigs via intracranial or oral inoculation although with low attack rates and restricted PrPSc accumulation. The objective of this study was to assess the potential for cross-species transmission of pig-passaged CWD using bioassay in transgenic mice. Transgenic mice expressing human (Tg40), bovine (TgBovXV) or porcine (Tg002) PRNP were inoculated intracranially with 1% brain homogenate from a pig that had been intracranially inoculated with a pool of CWD from white-tailed deer. This pig developed neurological clinical signs, was euthanized at 64 months post-inoculation, and PrPSc was detected in the brain. Mice were monitored daily for clinical signs of disease until the end of the study. Mice were considered positive if PrPSc was detected in the brain using an enzyme immunoassay (EIA). In transgenic mice expressing porcine prion protein the average incubation period was 167 days post-inoculation (dpi) and 3/27 mice were EIA positive (attack rate = 11%). All 3 mice were found dead and clinical signs were not noted prior to death. One transgenic mouse expressing bovine prion protein was euthanized due to excessive scratching at 617 dpi and 2 mice culled at the end of the study at 700 dpi were EIA positive resulting in an overall attack rate of 3/16 (19%). None of the transgenic mice expressing human prion protein that died or were euthanized up to 769 dpi were EIA positive and at study end point at 800 dpi 2 mice had positive EIA results (overall attack rate = 2/20 = 10%). The EIA optical density (OD) readings for all positive mice were at the lower end of the reference range (positive mice range, OD = 0.266-0.438; test positive reference range, OD = 0.250-4.000). To the authors’ knowledge, cervid-derived CWD isolates have not been successfully transmitted to transgenic mice expressing human prion protein. The successful transmission of pig-passaged CWD to Tg40 mice reported here suggests that passage of the CWD agent through pigs results in a change of the transmission characteristics which reduces the transmission barrier of Tg40 mice to the CWD agent. If this biological behavior is recapitulated in the original host species, passage of the CWD agent through pigs could potentially lead to increased pathogenicity of the CWD agent in humans.
cwd scrapie pigs oral routes
***> However, at 51 months of incubation or greater, 5 animals were positive by one or more diagnostic methods. Furthermore, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study) suggesting that swine are potential hosts for the agent of scrapie. <***
>*** Although the current U.S. feed ban is based on keeping tissues from TSE infected cattle from contaminating animal feed, swine rations in the U.S. could contain animal derived components including materials from scrapie infected sheep and goats. These results indicating the susceptibility of pigs to sheep scrapie, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health. <***
***> Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 month group was positive by EIA. PrPSc was detected by QuIC in at least one of the lymphoid tissues examined in 5/6 pigs in the intracranial <6 months group, 6/7 intracranial >6 months group, 5/6 pigs in the oral <6 months group, and 4/6 oral >6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%).
***> Conclusions: This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge. CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period. This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease. Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research
Title: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease
Author
item Greenlee, Justin item Moore, S - Orise Fellow item Smith, Jodi - Iowa State University item Kunkle, Robert item West Greenlee, M - Iowa State University Submitted to: American College of Veterinary Pathologists Meeting Publication Type: Abstract Only Publication Acceptance Date: 8/12/2015 Publication Date: N/A Citation: N/A
Interpretive Summary:
Technical Abstract: The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n=5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the two inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy. In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, two distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.
223. Scrapie in white-tailed deer: a strain of the CWD agent that efficiently transmits to sheep?
Justin J. Greenleea, Robyn D. Kokemullera, S. Jo Moorea and Heather West Greenleeb
aVirus and Prion Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, Ames, IA, USA; bDepartment of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
CONTACT Justin J. Greenlee Justin.Greenlee@ars.usda.gov
ABSTRACT
Scrapie is a transmissible spongiform encephalopathy of sheep and goats that is associated with widespread accumulation of abnormal prion protein (PrPSc) in the central nervous and lymphoid tissues. Chronic wasting disease (CWD) is the natural prion disease of cervid species, and the tissue distribution of PrPSc in affected cervids is similar to scrapie in sheep. There are several lines of evidence that suggest that multiple strains of CWD exist, which may affect the agent’s potential to transmit to hosts of the same or different species. We inoculated white-tailed deer with the scrapie agent from ARQ/ARQ sheep, which resulted in 100% attack rates by either the intracranial or oronasal route of inoculation. When examining tissues from the brainstems or lymphoid tissues by traditional diagnostic methods such as immunohistochemistry or western blots, it is difficult to differentiate tissues from deer infected with scrapie from those infected with CWD. However, there are several important differences between tissues from scrapie-infected white-tailed deer (WTD scrapie) and those infected with CWD (WTD CWD). First, there are different patterns of PrPSc deposition in the brains of infected deer: brain tissues from deer with WTD scrapie had predominantly particulate and stellate immunoreactivity whereas those from deer with WTD-CWD had large aggregates and plaque-like deposits. Secondly, the incubation periods of WTD scrapie isolates are longer than CWD isolates in mice expressing cervid prion protein. Most notably, the transmission potential of these two isolates back to sheep is distinctly different. Attempts to transmit various CWD isolates to sheep by the oral or oronasal routes have been unsuccessful despite observation periods of up to 7 years. However, WTD scrapie efficiently transmitted back to sheep by the oronasal route. Upon transmission back to sheep, the WTD scrapie isolate exhibited different phenotypic properties when compared to the sheep receiving the original sheep scrapie inoculum including different genotype susceptibilities, distinct PrPSc deposition patterns, and much more rapid incubation periods in transgenic mice expressing the ovine prion protein. The scrapie agent readily transmits between sheep and deer after oronasal exposure. This could confound the identification of CWD strains in deer and the eradication of scrapie from sheep.
MONDAY, NOVEMBER 30, 2020
***> REPORT OF THE MEETING OF THE OIE SCIENTIFIC COMMISSION FOR ANIMAL DISEASES Paris, 9–13 September 2019 BSE, TSE, PRION
**> see updated concerns with atypical BSE from feed and zoonosis...terry
***> Several experiments have demonstrated the ability of the AS agent to transmit within the natural host after intracranial inoculation [14–16].
***> One study found that the AS agent could transmit after a high oral dose of AS brain homogenate [17].
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced into Great Britain? A Qualitative Risk Assessment October 2012
snip.....
In the USA, under the Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law. Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and
2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES.
It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.
snip.....
36% in 2007 (Almberg et al., 2011). In such areas, population declines of deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of Colorado, the prevalence can be as high as 30% (EFSA, 2011). The clinical signs of CWD in affected adults are weight loss and behavioural changes that can span weeks or months (Williams, 2005). In addition, signs might include excessive salivation, behavioural alterations including a fixed stare and changes in interaction with other animals in the herd, and an altered stance (Williams, 2005). These signs are indistinguishable from cervids experimentally infected with bovine spongiform encephalopathy (BSE). Given this, if CWD was to be introduced into countries with BSE such as GB, for example, infected deer populations would need to be tested to differentiate if they were infected with CWD or BSE to minimise the risk of BSE entering the human food-chain via affected venison. snip..... The rate of transmission of CWD has been reported to be as high as 30% and can approach 100% among captive animals in endemic areas (Safar et al., 2008).
snip.....
In summary, in endemic areas, there is a medium probability that the soil and surrounding environment is contaminated with CWD prions and in a bioavailable form. In rural areas where CWD has not been reported and deer are present, there is a greater than negligible risk the soil is contaminated with CWD prion. snip..... In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible... For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.
snip.....
Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.
snip.....
***> READ THIS VERY, VERY, CAREFULLY, AUGUST 1997 MAD COW FEED BAN WAS A SHAM, AS I HAVE STATED SINCE 1997! 3 FAILSAFES THE FDA ET AL PREACHED AS IF IT WERE THE GOSPEL, IN TERMS OF MAD COW BSE DISEASE IN USA, AND WHY IT IS/WAS/NOT A PROBLEM FOR THE USA, and those are;
BSE TESTING (failed terribly and proven to be a sham)
BSE SURVEILLANCE (failed terribly and proven to be a sham)
BSE 589.2001 FEED REGULATIONS (another colossal failure, and proven to be a sham)
these are facts folks. trump et al just admitted it with the feed ban.
see;
FDA Reports on VFD Compliance
John Maday
August 30, 2019 09:46 AM VFD-Form 007 (640x427)
Before and after the current Veterinary Feed Directive rules took full effect in January, 2017, the FDA focused primarily on education and outreach. ( John Maday ) Before and after the current Veterinary Feed Directive (VFD) rules took full effect in January, 2017, the FDA focused primarily on education and outreach to help feed mills, veterinarians and producers understand and comply with the requirements. Since then, FDA has gradually increased the number of VFD inspections and initiated enforcement actions when necessary. On August 29, FDA released its first report on inspection and compliance activities. The report, titled “Summary Assessment of Veterinary Feed Directive Compliance Activities Conducted in Fiscal Years 2016 – 2018,” is available online.
SUNDAY, SEPTEMBER 1, 2019
***> FDA Reports on VFD Compliance
TUESDAY, APRIL 18, 2017
*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***
IBNC Tauopathy or TSE Prion disease, it appears, no one is sure
Terry S. Singeltary Sr., 03 Jul 2015 at 16:53 GMT
PLOS ONE Journal
IBNC Tauopathy or TSE Prion disease, it appears, no one is sure
Terry S. Singeltary Sr., 03 Jul 2015 at 16:53 GMT
***however in 1 C-type challenged animal, Prion 2015 Poster Abstracts S67 PrPsc was not detected using rapid tests for BSE.
***Subsequent testing resulted in the detection of pathologic lesion in unusual brain location and PrPsc detection by PMCA only.
*** IBNC Tauopathy or TSE Prion disease, it appears, no one is sure ***
WEDNESDAY, DECEMBER 23, 2020
Idiopathic Brainstem Neuronal Chromatolysis IBNC BSE TSE Prion a Review 2020
***> Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle.
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.
***> Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle.
P-088 Transmission of experimental CH1641-like scrapie to bovine PrP overexpression mice
Kohtaro Miyazawa1, Kentaro Masujin1, Hiroyuki Okada1, Yuichi Matsuura1, Takashi Yokoyama2
1Influenza and Prion Disease Research Center, National Institute of Animal Health, NARO, Japan; 2Department of Planning and General Administration, National Institute of Animal Health, NARO
Introduction: Scrapie is a prion disease in sheep and goats. CH1641-lke scrapie is characterized by a lower molecular mass of the unglycosylated form of abnormal prion protein (PrpSc) compared to that of classical scrapie. It is worthy of attention because of the biochemical similarities of the Prpsc from CH1641-like and BSE affected sheep. We have reported that experimental CH1641-like scrapie is transmissible to bovine PrP overexpression (TgBoPrP) mice (Yokoyama et al. 2010). We report here the further details of this transmission study and compare the biological and biochemical properties to those of classical scrapie affected TgBoPrP mice.
Methods: The details of sheep brain homogenates used in this study are described in our previous report (Yokoyama et al. 2010). TgBoPrP mice were intracerebrally inoculated with a 10% brain homogenate of each scrapie strain. The brains of mice were subjected to histopathological and biochemical analyses.
Results: Prpsc banding pattern of CH1641-like scrapie affected TgBoPrP mice was similar to that of classical scrapie affected mice. Mean survival period of CH1641-like scrapie affected TgBoPrP mice was 170 days at the 3rd passage and it was significantly shorter than that of classical scrapie affected mice (439 days). Lesion profiles and Prpsc distributions in the brains also differed between CH1641-like and classical scrapie affected mice.
Conclusion: We succeeded in stable transmission of CH1641-like scrapie to TgBoPrP mice. Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle.
snip...
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.
CH1641
WEDNESDAY, JULY 31, 2019
The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
49. The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
E. D. Cassmanna,b, S. J. Moorea,b, R. D. Kokemullera, A. Balkema-Buschmannc, M. H. Groschupcand J. J. Greenleea
aVirus and Prion Research Unit, National Animal Disease Center, ARS, United States Department of Agriculture, Ames, IA, USA (EDC, SJM, RDK, JJG); bOak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the U.S. Department of Energy (DOE) and the U.S. Department of Agriculture (USDA). ORISE is managed by ORAU under DOE contract number DE-SC0014664. (EDC, SJM), Department of Veterinary Pathology, Iowa State University, Ames, IA, USA (JDS); cInstitute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald – Isle of Riems, Germany (ABB, MHG)
CONTACT E. D. Cassmann eric.cassmann@usda.gov
ABSTRACT
Introduction: Transmissible mink encephalopathy (TME) is a fatal neurologic prion disease of farmed mink. Epidemiologic and experimental evidence following a Wisconsin outbreak in 1985 has linked TME to low-type bovine spongiform encephalopathy (BSE-L). Evidence suggests that farmed mink were likely exposed through feeding of BSE-L infected downer cattle. The interspecies transmission of TME to cattle has been documented. Recently, we demonstrated the susceptibility of sheep to cattle passaged TME by intracranial inoculation. The aim of the present study was to compare ovine passaged cattle TME to other prion diseases of food-producing animals. Using a bovine transgenic mouse model, we compared the disease phenotype of sheep TME to BSE-C and BSE-L.
Materials and Methods: Separate inoculants of sheep passaged TME were derived from animals with the VRQ/VRQ (VV136) and ARQ/VRQ (AV136) prion protein genotype. Transgenic bovinized mice (TgBovXV) were intracranially inoculated with 20 µl of 1% w/v brain homogenate. The disease phenotypes were characterized by comparing the attack rates, incubation periods, and vacuolation profiles in TgBovXV mice.
Results: The attack rate for BSE-C (13/13), BSE-L (18/18), and TMEVV (21/21) was 100%; whereas, the TMEAV group (15/19) had an incomplete attack rate. The average incubation periods were 299, 280, 310, and 541 days, respectively. The vacuolation profiles of BSE-L and TMEVV were most similar with mild differences observed in the thalamus and medulla. Vacuolation profiles from the BSE-C and TMEAV experimental groups were different than TMEVVand BSE-L.
Conclusion: Overall the phenotype of disease in TME inoculated transgenic mice was dependent on the sheep donor genotype (VV vs AV). The results of the present study indicate that TME isolated from VRQ/VRQ sheep is similar to BSE-L with regards to incubation period, attack rate, and vacuolation profile. Our findings are in agreement with previous research that found phenotypic similarities between BSE-L and cattle passaged TME in an ovine transgenic rodent model. In this study, the similarities between ovine TME and BSE-L are maintained after multiple interspecies passages.
Prion2019 Conference
2007
WEDNESDAY, JULY 31, 2019
The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
(b) the epidemiological and laboratory studies in the USA suggest the possibility of an occurrence of BSE infection in cattle as the origin of outbreaks of TME.
{c) there is also evidence from two experiments conducted in the USA that cattle, though susceptible to scrapie inocula prepared from sheep, express a pathology quite different from that of BSE and not convincingly diagnostic of an SE by histopathological criteria. Furthermore, neither of these studies can be regarded as a basis for extrapolation to the situation in the UK because the inocula used were either experimentally passaged or natural scrapie originating from Suffolk sheep; a minority breed in this country.
August 1988
Evidence That Transmissible Mink Encephalopathy Results From Feeding Infected Cattle
Evidence That Transmissible Mink Encephalopathy Results from Feeding Infected Cattle
Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.
snip...
The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...
NOW, in 1979, it was proven that indeed U.S. scrapie strain that was transmitted to U.S. cattle, did NOT produce a Transmissible Spongiform Encephalopathy (TSE) like the U.K. B.S.E., but a TSE unlike the U.K. B.S.E. SO what does all this tell us? it tells me that there is a possibility that a strain of mad cow disease was circulating in the U.S.A. long, long, before originally thought, only left to be ignored, while incubating and spreading.
3.57 The experiment which might have determined whether BSE and scrapie were caused by the same agent (ie, the feeding of natural scrapie to cattle) was never undertaken in the UK. It was, however, performed in the USA in 1979, when it was shown that cattle inoculated with the scrapie agent endemic in the flock of Suffolk sheep at the United States Department of Agriculture in Mission, Texas, developed a TSE quite unlike BSE.339 The findings of the initial transmission, though not of the clinical or neurohistological examination, were communicated in October 1988 to Dr Watson, Director of the CVL, following a visit by Dr Wrathall, one of the project leaders in the Pathology Department of the CVL, to the United States Department of Agriculture.340 The results were not published at this point, since the attempted transmission to mice from the experimental cow brain had been inconclusive. The results of the clinical and histological differences between scrapie-affected sheep and cattle were published in 1995. Similar studies in which cattle were inoculated intracerebrally with scrapie inocula derived from a number of scrapie-affected sheep of different breeds and from different States, were carried out at the US National Animal Disease Centre.341 The results, published in 1994, showed that this source of scrapie agent, though pathogenic for cattle, did not produce the same clinical signs of brain lesions characteristic of BSE.
3.58 There are several possible reasons why the experiment was not performed in the UK. It had been recommended by Sir Richard Southwood (Chairman of the Working Party on Bovine Spongiform Encephalopathy) in his letter to the Permanent Secretary of MAFF, Mr (now Sir) Derek Andrews, on 21 June 1988,342 though it was not specifically recommended in the Working Party Report or indeed in the Tyrrell Committee Report (details of the Southwood Working Party and the Tyrell Committee can be found in vol. 4: The Southwood Working Party, 1988–89 and vol. 11: Scientists after Southwood respectively). The direct inoculation of scrapie into calves was given low priority, because of its high cost and because it was known that it had already taken place in the USA.343 It was also felt that the results of such an experiment would be hard to interpret. While a negative result would be informative, a positive result would need to demonstrate that when scrapie was transmitted to cattle, the disease which developed in cattle was the same as BSE.344 Given the large number of strains of scrapie and the possibility that BSE was one of them, it would be necessary to transmit every scrapie strain to cattle separately, to test the hypothesis properly. Such an experiment would be expensive. Secondly, as measures to control the epidemic took hold, the need for the experiment from the policy viewpoint was not considered so urgent. It was felt that the results would be mainly of academic interest.345
3.59 Nevertheless, from the first demonstration of transmissibility of BSE in 1988, the possibility of differences in the transmission properties of BSE and scrapie was clear. Scrapie was transmissible to hamsters, but by 1988 attempts to transmit BSE to hamsters had failed. Subsequent findings increased that possibility.
337 Fraser, H., Bruce, M., Chree, A., McConnell, I. and Wells, G. (1992) Transmission of Bovine Spongiform Encephalopathy and Scrapie to Mice, Journal of General Virology, 73, 1891–7; Bruce, M., Chree, A., McConnell, I., Foster, J., Pearson, G. and Fraser, H. (1994) Transmission of Bovine Spongiform Encephalopathy and Scrapie to Mice: Strain Variation and the Species Barrier, Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences, 343, 405–11 338 Bruce, M., Will, R., Ironside, J., McConell, I., Drummond, D., Suttie, A., McCordie, L., Chree, A., Hope, J., Birkett, C., Cousens, S., Fraser, H. and Bostock, C. (1997) Transmissions to Mice Indicate that ‘New Variant’ CJD is Caused by the BSE Agent, Nature, 389, 498–501 339 Clark, W., Hourrigan, J. and Hadlow, W. (1995) Encephalopathy in Cattle Experimentally Infected with the Scrapie Agent, American Journal of Veterinary Research, 56, 606–12 340 YB88/10.00/1.1 341 Cutlip, R., Miller, J., Race, R., Jenny, A., Katz, J., Lehmkuhl, H., Debey, B. and Robinson, M. (1994) Intracerebral Transmission of Scrapie to Cattle, Journal of Infectious Diseases, 169, 814–20 342 YB88/6.21/1.2 343 YB88/11.17/2.4
31
Appendix I VISIT TO USA - OR A E WRATHALL — INFO ON BSE AND SCRAPIE
Dr Clark lately of the scrapie Research Unit, Mission Texas has
successfully transmitted ovine and caprine scrapie to cattle. The
experimental results have not been published but there are plans to do
this. This work was initiated in 1978. A summary of it is:-
Expt A 6 Her x Jer calves born in 1978 were inoculated as follows with
a 2nd Suffolk scrapie passage:-
i/c 1ml; i/m, 5ml; s/c 5ml; oral 30ml.
1/6 went down after 48 months with a scrapie/BSE-like disease.
Expt B 6 Her or Jer or HxJ calves were inoculated with angora Goat
virus 2/6 went down similarly after 36 months.
Expt C Mice inoculated from brains of calves/cattle in expts A & B were resistant, only 1/20 going down with scrapie and this was the reason given for not publishing.
Diagnosis in A, B, C was by histopath. No reports on SAF were given.
Dr Warren Foote indicated success so far in eliminating scrapie in offspring from experimentally— (and naturally) infected sheep by ET. He had found difficulty in obtaining embryos from naturally infected sheep (cf SPA).
Prof. A Robertson gave a brief accout of BSE. The us approach was to
32
accord it a very low profile indeed. Dr A Thiermann showed the picture in the "Independent" with cattle being incinerated and thought this was a fanatical incident to be avoided in the US at all costs.
BSE was not reported in USA.
4. Scrapie incidents (ie affected flocks) have shown a dramatic increase since 1978. In 1953 when the National Control scheme was started there were 10-14 incidents, in 1978 - 1 and in 1988 so far 60.
5. Scrapie agent was reported to have been isolated from a solitary fetus.
6. A western blotting diagnostic technique (? on PrP) shows some promise.
7. Results of a questionnaire sent to 33 states on the subject of the national sheep scrapie programme survey indicated
17/33 wished to drop it
6/33 wished to develop it
8/33 had few sheep and were neutral
Information obtained from Dr Wrathall‘s notes of a meeting of the u.s.
Animal Health Association at Little Rock, Arkansas Nov. 1988.
33
In Confidence - Perceptions of unconventional slow virus diseases of animals in the USA - APRIL-MAY 1989 - G A H Wells
3. Prof. A. Robertson gave a brief account of BSE. The US approach was to accord it a very low profile indeed. Dr. A Thiermann showed the picture in the ''Independent'' with cattle being incinerated and thought this was a fanatical incident to be avoided in the US at all costs. ...
VISIT TO USA - DR AE WRATHALL - INFO ON BSE AND SCRAPIE
1. Dr. Clark lately of the Scrapie Research Unit, Mission Texas has successfully transmitted ovine & caprine Scrapie to cattle. The experimental results have not been published but there are plans to do this. This work was initiated in 1978. A summary of it is;
snip...see handwritten notes from this here;
IN CONFIDENCE
Perceptions of an unconventional slow virus diseases of animals in the U.S.A. G A H Wells
Report of a Visit to the USA April-May 1989
Thursday, June 09, 2016
Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie Experiment 1964
How Did CWD Get Way Down In Medina County, Texas?
Confucius ponders...
Could the Scrapie experiments back around 1964 at Moore Air Force near Mission, Texas, could this area have been ground zero for CWD TSE Prion (besides the CWD cases that have waltzed across the Texas, New Mexico border near WSMR Trans Pecos region since around 2001)?
Epidemiology of Scrapie in the United States 1977
snip...
Scrapie Field Trial Experiments Mission, Texas A Scrapie Field Trial was developed at Mission, Texas, to provide additional information for the eradication program on the epidemiology of natural scrapie. The Mission Field Trial Station is located on 450 acres of pastureland, part of the former Moore Air Force Base, near Mission, Texas.
It was designed to bring previously exposed, and later also unexposed, sheep or goats to the Station and maintain and breed them under close observation for extended periods to determine which animals would develop scrapie and define more closely the natural spread and other epidemiological aspects of the disease.
The 547 previously exposed sheep brought to the Mission Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds.
They were purchased as field outbreaks occurred, and represented 21 bloodlines in which scrapie had been diagnosed.
Upon arrival at the Station, the sheep were maintained on pasture, with supplemental feeding as necessary.
The station was divided into 2 areas:
(1) a series of pastures and-pens occupied by male animals only, and
(2) a series of pastures and pens occupied by females and young progeny of both sexes.
... snip...
see full text ;
Thursday, June 09, 2016
Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie TSE Prion Experiment 1964 How Did CWD Get Way Down In Medina County, Texas?
doi:10.1016/S0021-9975(97)80022-9 Copyright © 1997 Published by Elsevier Ltd.
Second passage of a US scrapie agent in cattle
R.C. Cutlip, J.M. Miller and H.D. Lehmkuhl
United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
Received 10 September 1996; accepted 31 July 1997. Available online 25 May 2006.
Summary
Scrapie and bovine spongiform encephalopathy are similar chronic neurodegenerative diseases of sheep and cattle. An earlier study showed that, on first passage in cattle, a US scrapie agent caused an encephalopathy that was distinct from bovine spongiform encephalopathy (BSE). The present report describes a second passage in cattle, carried out because diseases caused by the spongiform encephalopathy agents often change in character with additional passages in abnormal hosts. For this work, young calves were inoculated intracerebrally with a pooled suspension of brain from cattle that had died of encephalopathy after experimental inoculation with brain from scrapie-affected sheep. The second passage disease was essentially identical with the first passage disease, as judged by clinical signs, histopathological findings and distribution of "prion protein scrapie" (PrPsc). This represents additional evidence to suggest that the US sheep scrapie agent tested is incapable of causing BSE in cattle.
SUNDAY, OCTOBER 4, 2020
Cattle Meat and Offal Imported from the United States of America, Canada and Ireland to Japan (Prions) Food Safety Commission of Japan
SEE HADLOW AND SCRAPIE !
P03.141
Aspects of the Cerebellar Neuropathology in Nor98
Gavier-Widén, D1; Benestad, SL2; Ottander, L1; Westergren, E1 1National Veterinary Insitute, Sweden; 2National Veterinary Institute,
Norway Nor98 is a prion disease of old sheep and goats. This atypical form of scrapie was first described in Norway in 1998. Several features of Nor98 were shown to be different from classical scrapie including the distribution of disease associated prion protein (PrPd) accumulation in the brain. The cerebellum is generally the most affected brain area in Nor98. The study here presented aimed at adding information on the neuropathology in the cerebellum of Nor98 naturally affected sheep of various genotypes in Sweden and Norway. A panel of histochemical and immunohistochemical (IHC) stainings such as IHC for PrPd, synaptophysin, glial fibrillary acidic protein, amyloid, and cell markers for phagocytic cells were conducted. The type of histological lesions and tissue reactions were evaluated. The types of PrPd deposition were characterized. The cerebellar cortex was regularly affected, even though there was a variation in the severity of the lesions from case to case. Neuropil vacuolation was more marked in the molecular layer, but affected also the granular cell layer. There was a loss of granule cells. Punctate deposition of PrPd was characteristic. It was morphologically and in distribution identical with that of synaptophysin, suggesting that PrPd accumulates in the synaptic structures. PrPd was also observed in the granule cell layer and in the white matter. The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
***The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
PR-26
NOR98 SHOWS MOLECULAR FEATURES REMINISCENT OF GSS
R. Nonno1, E. Esposito1, G. Vaccari1, E. Bandino2, M. Conte1, B. Chiappini1, S. Marcon1, M. Di Bari1, S.L. Benestad3, U. Agrimi1 1 Istituto Superiore di Sanità, Department of Food Safety and Veterinary Public Health, Rome, Italy (romolo.nonno@iss.it); 2 Istituto Zooprofilattico della Sardegna, Sassari, Italy; 3 National Veterinary Institute, Department of Pathology, Oslo, Norway
Molecular variants of PrPSc are being increasingly investigated in sheep scrapie and are generally referred to as "atypical" scrapie, as opposed to "classical scrapie". Among the atypical group, Nor98 seems to be the best identified. We studied the molecular properties of Italian and Norwegian Nor98 samples by WB analysis of brain homogenates, either untreated, digested with different concentrations of proteinase K, or subjected to enzymatic deglycosylation. The identity of PrP fragments was inferred by means of antibodies spanning the full PrP sequence. We found that undigested brain homogenates contain a Nor98-specific PrP fragment migrating at 11 kDa (PrP11), truncated at both the C-terminus and the N-terminus, and not N-glycosylated. After mild PK digestion, Nor98 displayed full-length PrP (FL-PrP) and N-glycosylated C-terminal fragments (CTF), along with increased levels of PrP11. Proteinase K digestion curves (0,006-6,4 mg/ml) showed that FL-PrP and CTF are mainly digested above 0,01 mg/ml, while PrP11 is not entirely digested even at the highest concentrations, similarly to PrP27-30 associated with classical scrapie. Above 0,2 mg/ml PK, most Nor98 samples showed only PrP11 and a fragment of 17 kDa with the same properties of PrP11, that was tentatively identified as a dimer of PrP11. Detergent solubility studies showed that PrP11 is insoluble in 2% sodium laurylsorcosine and is mainly produced from detergentsoluble, full-length PrPSc. Furthermore, among Italian scrapie isolates, we found that a sample with molecular and pathological properties consistent with Nor98 showed plaque-like deposits of PrPSc in the thalamus when the brain was analysed by PrPSc immunohistochemistry. Taken together, our results show that the distinctive pathological feature of Nor98 is a PrP fragment spanning amino acids ~ 90-155. This fragment is produced by successive N-terminal and C-terminal cleavages from a full-length and largely detergent-soluble PrPSc, is produced in vivo and is extremely resistant to PK digestion.
*** Intriguingly, these conclusions suggest that some pathological features of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
119
A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes
Annick Le Dur*,?, Vincent Béringue*,?, Olivier Andréoletti?, Fabienne Reine*, Thanh Lan Laï*, Thierry Baron§, Bjørn Bratberg¶, Jean-Luc Vilotte?, Pierre Sarradin**, Sylvie L. Benestad¶, and Hubert Laude*,? +Author Affiliations
*Virologie Immunologie Moléculaires and ?Génétique Biochimique et Cytogénétique, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France; ?Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Interactions Hôte Agent Pathogène, 31066 Toulouse, France; §Agence Française de Sécurité Sanitaire des Aliments, Unité Agents Transmissibles Non Conventionnels, 69364 Lyon, France; **Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, 37380 Nouzilly, France; and ¶Department of Pathology, National Veterinary Institute, 0033 Oslo, Norway
***Edited by Stanley B. Prusiner, University of California, San Francisco, CA (received for review March 21, 2005)
Abstract Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and "cases" that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice.
*** These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
Monday, December 1, 2008
When Atypical Scrapie cross species barriers
Authors
Andreoletti O., Herva M. H., Cassard H., Espinosa J. C., Lacroux C., Simon S., Padilla D., Benestad S. L., Lantier F., Schelcher F., Grassi J., Torres, J. M., UMR INRA ENVT 1225, Ecole Nationale Veterinaire de Toulouse.France; ICISA-INlA, Madrid, Spain; CEA, IBiTec-5, DSV, CEA/Saclay, Gif sur Yvette cedex, France; National Veterinary Institute, Postboks 750 Sentrum, 0106 Oslo, Norway, INRA IASP, Centre INRA de Tours, 3738O Nouzilly, France.
Content
Atypical scrapie is a TSE occurring in small ruminants and harbouring peculiar clinical, epidemiological and biochemical properties. Currently this form of disease is identified in a large number of countries. In this study we report the transmission of an atypical scrapie isolate through different species barriers as modeled by transgenic mice (Tg) expressing different species PRP sequence.
The donor isolate was collected in 1995 in a French commercial sheep flock. inoculation into AHQ/AHQ sheep induced a disease which had all neuro-pathological and biochemical characteristics of atypical scrapie. Transmitted into Transgenic mice expressing either ovine or PrPc, the isolate retained all the described characteristics of atypical scrapie.
Surprisingly the TSE agent characteristics were dramatically different v/hen passaged into Tg bovine mice. The recovered TSE agent had biological and biochemical characteristics similar to those of atypical BSE L in the same mouse model. Moreover, whereas no other TSE agent than BSE were shown to transmit into Tg porcine mice, atypical scrapie was able to develop into this model, albeit with low attack rate on first passage.
Furthermore, after adaptation in the porcine mouse model this prion showed similar biological and biochemical characteristics than BSE adapted to this porcine mouse model. Altogether these data indicate.
(i) the unsuspected potential abilities of atypical scrapie to cross species barriers
(ii) the possible capacity of this agent to acquire new characteristics when crossing species barrier
These findings raise some interrogation on the concept of TSE strain and on the origin of the diversity of the TSE agents and could have consequences on field TSE control measures.
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
PLEASE NOTE;
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
Olivier Andreoletti, INRA Research Director, Institut National de la Recherche Agronomique (INRA) – École Nationale Vétérinaire de Toulouse (ENVT), invited speaker, presented the results of two recently published scientific articles of interest, of which he is co-author: ‘Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice’ (MarinMoreno et al., 2020) and ‘The emergence of classical BSE from atypical/Nor98 scrapie’ (Huor et al., 2019).
In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.
WEDNESDAY, JUNE 10, 2020
Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice
Atypical BSE prions showed a modification in their zoonotic ability after adaptation to sheep-PrP producing agents able to infect TgMet129 and TgVal129, bearing features that make them indistinguishable of sporadic Creutzfeldt-Jakob disease prions.
our results clearly indicate that atypical BSE adaptation to an ovine-PrP sequence could modify the prion agent to potentially infect humans, showing strain features indistinguishable from those of classic sCJD prions, even though they might or might not be different agents.
However, the expanding range of TSE agents displaying the capacity to transmit in human-PrP–expressing hosts warrants the continuation of the ban on meat and bone meal recycling and underscores the ongoing need for active surveillance
Transmission of the atypical/Nor98 scrapie agent to Suffolk sheep with VRQ/ARQ, ARQ/ARQ, and ARQ/ARR genotypes
Eric D. Cassmann,Najiba Mammadova,S. Jo Moore,Sylvie Benestad,Justin J. Greenlee
Published: February 11, 2021https://doi.org/10.1371/journal.pone.0246503
Citation: Cassmann ED, Mammadova N, Moore SJ, Benestad S, Greenlee JJ (2021) Transmission of the atypical/Nor98 scrapie agent to Suffolk sheep with VRQ/ARQ, ARQ/ARQ, and ARQ/ARR genotypes. PLoS ONE 16(2): e0246503. https://doi.org/10.1371/journal.pone.0246503
Editor: Gianluigi Zanusso, University of Verona, ITALY
Received: November 24, 2020; Accepted: January 21, 2021; Published: February 11, 2021
Abstract
Scrapie is a transmissible spongiform encephalopathy that occurs in sheep. Atypical/Nor98 scrapie occurs in sheep that tend to be resistant to classical scrapie and it is thought to occur spontaneously. The purpose of this study was to test the transmission of the Atypical/Nor98 scrapie agent in three genotypes of Suffolk sheep and characterize the distribution of misfolded prion protein (PrPSc). Ten sheep were intracranially inoculated with brain homogenate from a sheep with Atypical/Nor98 scrapie. All sheep with the ARQ/ARQ and ARQ/ARR genotypes developed Atypical/Nor98 scrapie confirmed by immunohistochemistry, and one sheep with the VRQ/ARQ genotype had detectable PrPSc consistent with Atypical/Nor98 scrapie at the experimental endpoint of 8 years. Sheep with mild early accumulations of PrPSc in the cerebellum had concomitant retinal PrPSc. Accordingly, large amounts of retinal PrPSc were identified in clinically affected sheep and sheep with dense accumulations of PrPSc in the cerebellum.
Introduction
Atypical/Nor98 scrapie (AS) is a fatal prion disease of sheep caused by a misfolded form of the prion protein. Unlike classical scrapie (CS), AS is thought to be a spontaneously occurring disease [1–3]. This is supported by the presence of AS in countries that are free of classical scrapie [4, 5]. It typically affects a single older sheep within a flock, and cases of AS are sporadic and isolated suggesting that natural transmission is unlikely.
The susceptibility of sheep to CS is closely related to polymorphisms in the prion protein gene (PRNP) [6, 7]. Polymorphisms associated with susceptibility or resistance to CS occur at codons 136, 154, and 171. Sheep with the V136R154Q171 and A136R154Q171 haplotypes are susceptible to CS; however, the amino acid polymorphisms A136, R154, and R171 are associated with relative resistance [8–10]. Conversely, naturally occurring cases of AS arise in sheep with the AHQ, ARQ, and ARR haplotypes, and a polymorphism substituting phenylalanine (F) at codon 141 in the PRNP gene increases the risk of AS [11–13].
Several experiments have demonstrated the ability of the AS agent to transmit within the natural host after intracranial inoculation [14–16]. One study found that the AS agent could transmit after a high oral dose of AS brain homogenate [17]. Nonetheless, AS is still considered unlikely to transmit under field conditions; therefore, eradication and surveillance programs for CS have allowed exceptions for AS. As research into AS unfolds, the biological relevance of this disease is gaining attention. Two studies have demonstrated phenotype changes in AS that imply a possible origin for classical scrapie [18] and classical BSE [19]. The present study was designed to generate AS brain material for subsequent projects to investigate interspecies transmission events. Herein, we report our findings after the experimental transmission of AS in sheep with the VRQ/ARQ, ARQ/ARQ, and ARQ/ARR genotypes. This study validates previous work on these genotypes and documents the early accumulation of PrPSc in the retina of sheep with AS.
Results and discussion
All three genotypes of sheep, VRQ/ARQ, ARQ/ARQ, and ARQ/ARR, were susceptible to the AS agent after intracranial inoculation of donor brain homogenate. The diagnosis of AS was confirmed by enzyme immunoassay (EIA) and immunohistochemistry (IHC) with the latter being confirmative. Previous studies have demonstrated experimental transmission of AS to AHQ/AHQ [14, 15] and ARQ/ARQ [16] genotype sheep after intracerebral transmission. Another study showed a phenotypic shift from AS to CH1641-like classical scrapie in a sheep with the AHQ/AHQ genotype [18]. In this study, sheep with the ARQ/ARR genotype had the shortest incubation period ranging from 4.9 years to the experimental endpoint of 8 years (Table 1), and the attack rate was 100% (5/5). Clinical signs were observed in all ARQ/ARR sheep except for a single wether that was culled early to help establish experimental endpoints. Three ARQ/ARR genotype sheep were euthanized due to clinical neurologic disease 4.9–6.7 years post-inoculation. Out of the three genotypes examined, only the ARQ/ARR genotype sheep developed clinical neurologic disease within the eight-year incubation period. In clinically neurologic sheep, we observed stiff legged and hypermetric ataxia (dysmetria), abnormal rear stance, generalized tremors, tremors of the lips, weight loss, and generalized malaise. The spectrum of clinical signs was comparable to other reports of experimental AS in sheep [14, 15]. Three ARQ/ARR genotype sheep (804, 927 and 948) with the most severe dysmetria also had the greatest amount of cerebellar PrPSc. Since dysmetria is typical of animals with cerebellar disease [20], the tendency to observe this as the most consistent and severe neurologic sign is likely related to the characteristic cerebellar accumulation of PrPSc in sheep with AS. The ARQ/ARQ genotype had a long incubation period and remained clinically asymptomatic, as also reported by Okada et al. [16].
Table 1. Results of atypical scrapie transmission in Suffolk sheep. https://doi.org/10.1371/journal.pone.0246503.t001
Sheep with the ARQ/ARQ genotype were positive for AS PrPSc by IHC (2/2). One positive wether remained asymptomatic and was necropsied at the experimental endpoint; whereas, the other sheep was culled due to intercurrent disease around four years post-inoculation. Out of the three original VRQ/ARQ genotype sheep, a single presymptomatic wether had PrPSc in the cerebellum and retina at the experimental endpoint of 8.1 years. The other two sheep succumbed to intercurrent disease, and they did not have detectable PrPSc by means of IHC or EIA at 1.2- and 2.9-years post-inoculation. The VRQ allele, that is generally associated with susceptibility to classical scrapie, is usually absent from naturally occurring AS cases [5, 12, 21]. However, in a study of AS cases from Great Britain, a single VRQ/ARQ case was reported [22]. The prolonged incubation period after intracranial inoculation of AS in a VRQ/ARQ genotype sheep is compatible with the low prevalence in field cases of AS. In fact, field cases of AS often have a polymorphism substituting phenylalanine (F) at codon 141 in the PRNP gene, and most cases have either the AF141RQ or AHQ alleles [12]. All of the sheep in this study contained the amino acid leucine (L) at codon 141.
In order to confirm that sheep had AS and rule out concomitant infection with classical scrapie, all tissues were examined by IHC for PrPSc. The distribution of PrPSc in the brains of sheep was consistent with AS. Immunolabeling of PrPSc appeared as granular and punctate deposits and was largely restricted to the molecular layer of the cerebellum (Fig 1A). Small amounts of punctate and granular staining were also seen in the cerebral cortex, basal nuclei, thalamus, and midbrain. In classical scrapie, PrPSc is found in the dorsal motor nucleus of the vagus nerve (DMNV), one of the early sites of central nervous system accumulation, and in the lymphoid tissue [3]. In the present experiment, PrPSc was observed in the spinal trigeminal tract (Fig 1B), and there was a lack of staining for PrPSc in the DMNV (Fig 1C). Additionally, no PrPSc was detectable by IHC in the lymphoid or peripheral tissues of any sheep; it remained confined to the CNS. Other studies have demonstrated infectivity in peripheral and lymphoid tissues that were IHC negative [17, 23]. This distribution of PrPSc in the present study was consistent with AS in sheep [1, 14]. Furthermore, all genotypes of sheep had similar PrPSc distributions; however, the density of staining was less severe in asymptomatic ARQ/ARQ and VRQ/ARQ genotype sheep. Given a longer incubation period culminating in clinical disease, it is expected that these genotypes would develop more severe PrPSc deposition similar to ARQ/ARR genotype sheep. PrPSc was also found in the spinal cords of each genotype of sheep. Staining of PrPSc appeared as small particulate or fine granular deposits in the dorsal horn. In sheep with the ARQ/ARR genotype, there was minimal PrPSc and it was usually observed in the cervical cord alone. Sheep 929 that lived to the experimental endpoint had PrPSc in both the cervical and thoracic cord segments. In sheep 958 (ARQ/ARQ) and 943 (VRQ/ARQ), there was a mild amount of PrPSc in the dorsal horn of the cervical, thoracic, and lumbar spinal cord segments. This differs from classical scrapie that involves the entire grey matter of the spinal cord in late stage disease [24].
Fig 1. Immunoreactivity of PrPSc in sheep with atypical scrapie.
(A) There is a large amount of PrPSc (red color) within the molecular layer of cerebellum in sheep 958 (ARQ/ARQ). (B) PrPSc (red color) is confined to the spinal trigeminal tract in the medulla oblongata in sheep 948 (ARQ/ARR). (C) The dorsal motor nucleus of the vagus nerve (circle) is devoid of PrPSc in sheep 948. (D) There are multifocal patchy aggregates of PrPSc (red color) in the molecular layer of the cerebellum in sheep 943 (VRQ/ARQ). (E) A small amount of PrPSc (red color) is present in the retina of sheep 943. (F) In sheep 958 there are large amounts of PrPSc (red color) in the plexiform layers of the retina.
We performed both IHC and EIA on cerebellum, cerebrum (parietal cortex), and medulla oblongata at the level of the obex. For the ARQ/ARR and ARQ/ARQ genotype sheep, there was 100% (7/7) agreement between IHC and EIA at detecting PrPSc in the cerebellum. In contrast, the single positive VRQ/ARQ sheep was IHC positive and EIA negative in the cerebellum. This discrepancy was presumably due to the patchy and sparse distribution of PrPSc in the cerebellum (Fig 1D). PrPSc was rarely observed in other brain regions of this animal; however, PrPSc was detected in the retina with IHC (Fig 1E). Moreover, retinal PrPSc was present in each genotype of sheep with atypical scrapie PrPSc in the cerebellum. In clinical sheep with abundant cerebellar PrPSc, there were large amounts of PrPSc in the retina (Fig 1F). PrPSc occurred mostly in the inner and outer plexiform layers, but some minimal labeling was seen in the ganglion and nuclear cell layers. Other reports that describe atypical scrapie do not report retinal PrPSc [1–5, 14–16, 25, 26]. In this study, sheep intracranially inoculated with the atypical scrapie agent accumulated retinal PrPSc in the early stages of disease concomitant with cerebellar PrPSc. This is significant because, sequentially, retinal PrPSc accumulates early in disease; therefore, IHC of retinal tissue may be more sensitive compared to non-cerebellar brain regions.
This experiment demonstrated the transmission of atypical scrapie to three genotypes of sheep after intracranially inoculation, and it is the first study demonstrating experimental transmission to sheep with a VRQ/ARQ PRNP genotype. Additionally, atypical scrapie is further characterized by demonstrating early accumulation of PrPSc in the retina of experimentally inoculated sheep.
Materials and methods Animals for this experiment were derived from a known scrapie-free flock at the United States Department of Agriculture National Animal Disease Center in Ames, IA. This study used ten Suffolk sheep, nine wethers and one ewe. Nine sheep were 1 year old at the time of inoculation. A single sheep, #958, was 2 years old. Sheep in this study had three distinct PRNP genotypes: ARQ/ARQ, ARQ/ARR, and VRQ/ARQ. The genotypes were determined using polymerase chain reaction and Sanger sequencing as previously described [27]. Sheep were homozygous at other known polymorphic sites M112, G127, M137, S138, L141, R151, M157, N176, H180, Q189, T195, T196, R211, Q220, and R223.
The inoculum for this experiment was cerebral homogenate from an AHQ/ARH genotype sheep with atypical scrapie from Norway (Hedalen). The inoculum was obtained through a collaboration with Sylvie Benestad at the Norwegian Veterinary Institute. The brain homogenate was prepared as a 10% w/v homogenate. Sheep were intracranially inoculated with 1 ml (0.1 grams) of brain homogenate. The procedure has been described previously [28]. Briefly, the sheep were anesthetized with xylazine and a surgical field was prepped over the junction of parietal and frontal bones. A 1-cm skin incision was made, and then a 1-mm hole was drilled along the midline of the calvaria. A 9-cm spinal needle was inserted through the hole, and the inoculum was injected into the cranium. Sheep were kept in a biosecurity level 2 indoor pen for two weeks following inoculation and then moved to an outdoor area. They were fed a daily ration of pelleted and loose alfalfa hay. Sheep were monitored daily for any maladies or other clinical signs consistent with scrapie. The experimental endpoint for this experiment included the earliest of either unequivocal neurologic disease or 8 years post-inoculation. The final 8-year endpoint was established by performing a preliminarily cull of sheep 933 to help determine an appropriate endpoint. Sheep were euthanized at the onset of clinical disease or untreatable intercurrent disease. The method of euthanasia was intravenous administration of sodium pentobarbital as per label directions or as directed by an animal resources attending veterinarian. Clinical signs of disease included abnormalities in gate and/or stance, and ataxia.
A full post-mortem examination was performed on each sheep, and a routine set of tissues were collected consistent with previous experiments [29, 30]. A duplicate set of the following tissues were frozen or saved to 10% buffered neutral formalin: brain, spinal cord, pituitary, trigeminal ganglia, eyes, sciatic nerve, third eyelid, palatine tonsil, pharyngeal tonsil, lymph nodes (mesenteric, retropharyngeal, prescapular, and popliteal), spleen, esophagus, forestomaches, intestines, rectal mucosa, thymus, liver, kidney, urinary bladder, pancreas, salivary gland, thyroid gland, adrenal gland, trachea, lung, turbinate, nasal planum, heart, tongue, masseter, diaphragm, triceps brachii, biceps femoris, and psoas major. Formalin fixed tissues were processed, paraffin embedded, and sectioned at optimal thickness (brain, 4 μm; lymphoid, 3 μm; and other, 5 μm) for hematoxylin and eosin staining and IHC. For IHC, a cocktail of the monoclonal anti-PrPSc antibodies F89/160.1.5 [31] and F99/97.6.1 [32] was applied at a concentration of 5 μg/mL using an automated stainer. Frozen portions of cerebellum, parietal cerebral cortex, and brainstem at the level of the obex were homogenized and tested for the presence of PrPSc using a commercially available EIA (HerdChek; IDEXX Laboratories, Westbrook, ME) according to kit instructions.
Ethics statement
snip...
***> Atypical/Nor98 scrapie occurs in sheep that tend to be resistant to classical scrapie and it is thought to occur spontaneously.
***> Unlike classical scrapie (CS), AS is thought to be a spontaneously occurring disease [1–3].
***> It typically affects a single older sheep within a flock, and cases of AS are sporadic and isolated suggesting that natural transmission is unlikely.
***> Several experiments have demonstrated the ability of the AS agent to transmit within the natural host after intracranial inoculation [14–16].
***> One study found that the AS agent could transmit after a high oral dose of AS brain homogenate [17].
***> Nonetheless, AS is still considered unlikely to transmit under field conditions; therefore, eradication and surveillance programs for CS have allowed exceptions for AS.
I once again, with great urgency, strenuously urge the USDA and the OIE et al to revoke the exemption of the legal global trading of atypical Nor-98 scrapie TSE Prion, and make any and all, atypical scrapie a mandatory reportable disease ASAP!...terry
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies Location: Virus and Prion Research
Title: Transmission of the atypical/nor98 scrapie agent to suffolk sheep with VRQ/ARQ, ARQ/ARQ, and ARQ/ARR genotypes
Author item Cassmann, Eric item MAMMADOVA, JAJIBA - Orise Fellow item BENESTAD, SYLVIE - Norwegian Veterinary Institute item MOORE, SARA JO - Orise Fellow item Greenlee, Justin Submitted to: PLoS ONE Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/29/2021 Publication Date: N/A Citation: N/A
Interpretive Summary: Atypical scrapie is a prion disease that affects sheep. Unlike classical scrapie, atypical scrapie is thought to occur spontaneously, and it is unlikely to transmit between sheep under natural conditions. Another notable distinction between classical and atypical scrapie is the prion protein genotype of afflicted sheep and the locations in the brain where misfolded prions accumulate. Atypical scrapie generally occurs in sheep that are resistant to classical scrapie. Misfolded prions are predominantly found in the cerebellum for atypical scrapie and not in the brainstem as seen with classical scrapie. Atypical scrapie is a relevant disease because of its potential association with other prion diseases. Some research has shown that the atypical scrapie agent can undergo a transformation of disease forms that makes it appear like classical scrapie or classical bovine spongiform encephalopathy (mad cow disease). Therefore, atypical scrapie is thought to be a possible source for these prion diseases. We investigated the transmission of the atypical scrapie agent to sheep with three different prion protein genotypes. A diagnosis of atypical scrapie was made in all three genotypes of sheep. Misfolded prion protein was detected earliest in the cerebellum and the retina. This is the first report describing the early accumulation of misfolded prions in the retina of sheep with atypical scrapie. Understanding where misfolded prions accumulate in cases of atypical scrapie can lead to better detection earlier in the disease. Furthermore, the materials derived from this experiment will aid in investigating origins of other prion diseases.
Technical Abstract: Scrapie is a transmissible spongiform encephalopathy that occurs in sheep. Atypical/Nor98 scrapie occurs in sheep with that tend to be resistant to classical scrapie and it is thought to occur spontaneously. The purpose of this study was to test the transmission of the Atypical/Nor98 scrapie agent in three genotypes of Suffolk sheep and characterize the distribution of misfolded prion protein (PrPSc). Ten sheep were intracranially inoculated with brain homogenate from a sheep with Atypical/Nor98 scrapie. All sheep with the ARQ/ARQ and ARQ/ARR genotypes developed Atypical/Nor98 scrapie confirmed by immunohistochemistry, and one (1/3) sheep with the VRQ/ARQ genotype had detectable PrPSc consistent with Atypical/Nor98 scrapie at the experimental endpoint of 8 years. Sheep with mild early accumulations of PrPSc in the cerebellum had concomitant retinal PrPSc. Accordingly, large amounts of retinal PrPSc were identified in clinically affected sheep and sheep with dense accumulations of PrPSc in the cerebellum.
***> Atypical/Nor98 scrapie occurs in sheep that tend to be resistant to classical scrapie and it is thought to occur spontaneously.
***> Unlike classical scrapie (CS), AS is thought to be a spontaneously occurring disease [1–3].
***> It typically affects a single older sheep within a flock, and cases of AS are sporadic and isolated suggesting that natural transmission is unlikely.
***> Several experiments have demonstrated the ability of the AS agent to transmit within the natural host after intracranial inoculation [14–16].
***> One study found that the AS agent could transmit after a high oral dose of AS brain homogenate [17].
***> Nonetheless, AS is still considered unlikely to transmit under field conditions; therefore, eradication and surveillance programs for CS have allowed exceptions for AS.
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.
17 Nor98-like cases since the beginning of RSSS. No animals have tested positive for classical scrapie in FY 2021.
WEDNESDAY, FEBRUARY 03, 2021
Scrapie TSE Prion United States of America a Review February 2021 Singeltary et al
THURSDAY, JANUARY 7, 2021
Atypical Nor-98 Scrapie TSE Prion USA State by State Update January 2021
TUESDAY, SEPTEMBER 22, 2020
APHIS USDA MORE SCRAPIE ATYPICAL Nor-98 Confirmed USA September 15 2020
MONDAY, JULY 27, 2020
APHIS USDA Nor98-like scrapie was confirmed in a sheep sampled at slaughter in May 2020
TUESDAY, JANUARY 26, 2021
Pennsylvania Scrapie Update Outbreak August 2018 and 3 Nor-98 atypical Cases Detected
MONDAY, JULY 13, 2020
Efficient transmission of classical scrapie agent x124 by intralingual route to genetically susceptible sheep with a low dose inoculum
*** Singeltary reply ; Molecular, Biochemical and Genetic Characteristics of BSE in Canada Singeltary reply ;
WEDNESDAY, MAY 29, 2019
***> Incomplete inactivation of atypical scrapie following recommended autoclave decontamination procedures
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
***> 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. <***
Transmission of scrapie prions to primate after an extended silent incubation period
Emmanuel E. Comoy, Jacqueline Mikol, Sophie Luccantoni-Freire, Evelyne Correia, Nathalie Lescoutra-Etchegaray, Valérie Durand, Capucine Dehen, Olivier Andreoletti, Cristina Casalone, Juergen A. Richt, Justin J. Greenlee, Thierry Baron, Sylvie L. Benestad, Paul Brown & Jean-Philippe Deslys Scientific Reports volume 5, Article number: 11573 (2015) | Download Citation
Abstract
Classical bovine spongiform encephalopathy (c-BSE) is the only animal prion disease reputed to be zoonotic, causing variant Creutzfeldt-Jakob disease (vCJD) in humans and having guided protective measures for animal and human health against animal prion diseases. Recently, partial transmissions to humanized mice showed that the zoonotic potential of scrapie might be similar to c-BSE. We here report the direct transmission of a natural classical scrapie isolate to cynomolgus macaque, a highly relevant model for human prion diseases, after a 10-year silent incubation period, with features similar to those reported for human cases of sporadic CJD. Scrapie is thus actually transmissible to primates with incubation periods compatible with their life expectancy, although fourfold longer than BSE. Long-term experimental transmission studies are necessary to better assess the zoonotic potential of other prion diseases with high prevalence, notably Chronic Wasting Disease of deer and elk and atypical/Nor98 scrapie.
SNIP...
Discussion We describe the transmission of spongiform encephalopathy in a non-human primate inoculated 10 years earlier with a strain of sheep c-scrapie. Because of this extended incubation period in a facility in which other prion diseases are under study, we are obliged to consider two alternative possibilities that might explain its occurrence. We first considered the possibility of a sporadic origin (like CJD in humans). Such an event is extremely improbable because the inoculated animal was 14 years old when the clinical signs appeared, i.e. about 40% through the expected natural lifetime of this species, compared to a peak age incidence of 60–65 years in human sporadic CJD, or about 80% through their expected lifetimes. 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.
The second possibility is a laboratory cross-contamination. Three facts make this possibility equally unlikely. First, handling of specimens in our laboratory is performed with fastidious attention to the avoidance of any such cross-contamination. Second, no laboratory cross-contamination has ever been documented in other primate laboratories, including the NIH, even between infected and uninfected animals housed in the same or adjacent cages with daily intimate contact (P. Brown, personal communication). Third, the cerebral lesion profile is different from all the other prion diseases we have studied in this model19, with a correlation between cerebellar lesions (massive spongiform change of Purkinje cells, intense PrPres staining and reactive gliosis26) and ataxia. The iron deposits present in the globus pallidus are a non specific finding that have been reported previously in neurodegenerative diseases and aging27. Conversely, the thalamic lesion was reminiscent of a metabolic disease due to thiamine deficiency28 but blood thiamine levels were within normal limits (data not shown). The preferential distribution of spongiform change in cortex associated with a limited distribution in the brainstem is reminiscent of the lesion profile in MM2c and VV1 sCJD patients29, but interspecies comparison of lesion profiles should be interpreted with caution. It is of note that the same classical scrapie isolate induced TSE in C57Bl/6 mice with similar incubation periods and lesional profiles as a sample derived from a MM1 sCJD patient30.
We are therefore confident that the illness in this cynomolgus macaque represents a true transmission of a sheep c-scrapie isolate directly to an old-world monkey, which taxonomically resides in the primate subdivision (parvorder of catarrhini) that includes humans. With an homology of its PrP protein with humans of 96.4%31, cynomolgus macaque constitutes a highly relevant model for assessing zoonotic risk of prion diseases. Since our initial aim was to show the absence of transmission of scrapie to macaques in the worst-case scenario, we obtained materials from a flock of naturally-infected sheep, affecting animals with different genotypes32. This c-scrapie isolate exhibited complete transmission in ARQ/ARQ sheep (332 ± 56 days) and Tg338 transgenic mice expressing ovine VRQ/VRQ prion protein (220 ± 5 days) (O. Andreoletti, personal communication). From the standpoint of zoonotic risk, it is important to note that sheep with c-scrapie (including the isolate used in our study) have demonstrable infectivity throughout their lymphoreticular system early in the incubation period of the disease (3 months-old for all the lymphoid organs, and as early as 2 months-old in gut-associated lymph nodes)33. In addition, scrapie infectivity has been identified in blood34, milk35 and skeletal muscle36 from asymptomatic but scrapie infected small ruminants which implies a potential dietary exposure for consumers.
Two earlier studies have reported the occurrence of clinical TSE in cynomolgus macaques after exposures to scrapie isolates. In the first study, the “Compton” scrapie isolate (derived from an English sheep) and serially propagated for 9 passages in goats did not transmit TSE in cynomolgus macaque, rhesus macaque or chimpanzee within 7 years following intracerebral challenge1; conversely, after 8 supplementary passages in conventional mice, this “Compton” isolate induced TSE in a cynomolgus macaque 5 years after intracerebral challenge, but rhesus macaques and chimpanzee remained asymptomatic 8.5 years post-exposure8. However, multiple successive passages that are classically used to select laboratory-adapted prion strains can significantly modify the initial properties of a scrapie isolate, thus questioning the relevance of zoonotic potential for the initial sheep-derived isolate. The same isolate had also induced disease into squirrel monkeys (new-world monkey)9. A second historical observation reported that a cynomolgus macaque developed TSE 6 years post-inoculation with brain homogenate from a scrapie-infected Suffolk ewe (derived from USA), whereas a rhesus macaque and a chimpanzee exposed to the same inoculum remained healthy 9 years post-exposure1. This inoculum also induced TSE in squirrel monkeys after 4 passages in mice. Other scrapie transmission attempts in macaque failed but had more shorter periods of observation in comparison to the current study. Further, it is possible that there are differences in the zoonotic potential of different scrapie strains.
The most striking observation in our study is the extended incubation period of scrapie in the macaque model, which has several implications. Firstly, our observations constitute experimental evidence in favor of the zoonotic potential of c-scrapie, at least for this isolate that has been extensively studied32,33,34,35,36. The cross-species zoonotic ability of this isolate should be confirmed by performing duplicate intracerebral exposures and assessing the transmissibility by the oral route (a successful transmission of prion strains through the intracerebral route may not necessarily indicate the potential for oral transmission37). However, such confirmatory experiments may require more than one decade, which is hardly compatible with current general management and support of scientific projects; thus this study should be rather considered as a case report.
Secondly, transmission of c-BSE to primates occurred within 8 years post exposure for the lowest doses able to transmit the disease (the survival period after inoculation is inversely proportional to the initial amount of infectious inoculum). The occurrence of scrapie 10 years after exposure to a high dose (25 mg) of scrapie-infected sheep brain suggests that the macaque has a higher species barrier for sheep c-scrapie than c-BSE, although it is notable that previous studies based on in vitro conversion of PrP suggested that BSE and scrapie prions would have a similar conversion potential for human PrP38.
Thirdly, prion diseases typically have longer incubation periods after oral exposure than after intracerebral inoculations: since humans can develop Kuru 47 years after oral exposure39, an incubation time of several decades after oral exposure to scrapie would therefore be expected, leading the disease to occur in older adults, i.e. the peak age for cases considered to be sporadic disease, and making a distinction between scrapie-associated and truly sporadic disease extremely difficult to appreciate.
Fourthly, epidemiologic evidence is necessary to confirm the zoonotic potential of an animal disease suggested by experimental studies. A relatively short incubation period and a peculiar epidemiological situation (e.g., all the first vCJD cases occurring in the country with the most important ongoing c-BSE epizootic) led to a high degree of suspicion that c-BSE was the cause of vCJD. Sporadic CJD are considered spontaneous diseases with an almost stable and constant worldwide prevalence (0.5–2 cases per million inhabitants per year), and previous epidemiological studies were unable to draw a link between sCJD and classical scrapie6,7,40,41, even though external causes were hypothesized to explain the occurrence of some sCJD clusters42,43,44. However, extended incubation periods exceeding several decades would impair the predictive values of epidemiological surveillance for prion diseases, already weakened by a limited prevalence of prion diseases and the multiplicity of isolates gathered under the phenotypes of “scrapie” and “sporadic CJD”.
Fifthly, considering this 10 year-long incubation period, together with both laboratory and epidemiological evidence of decade or longer intervals between infection and clinical onset of disease, no premature conclusions should be drawn from negative transmission studies in cynomolgus macaques with less than a decade of observation, as in the aforementioned historical transmission studies of scrapie to primates1,8,9. Our observations and those of others45,46 to date are unable to provide definitive evidence regarding the zoonotic potential of CWD, atypical/Nor98 scrapie or H-type BSE. The extended incubation period of the scrapie-affected macaque in the current study also underscores the limitations of rodent models expressing human PrP for assessing the zoonotic potential of some prion diseases since their lifespan remains limited to approximately two years21,47,48. This point is illustrated by the fact that the recently reported transmission of scrapie to humanized mice was not associated with clinical signs for up to 750 days and occurred in an extreme minority of mice with only a marginal increase in attack rate upon second passage13. The low attack rate in these studies is certainly linked to the limited lifespan of mice compared to the very long periods of observation necessary to demonstrate the development of scrapie. Alternatively, one could estimate that a successful second passage is the result of strain adaptation to the species barrier, thus poorly relevant of the real zoonotic potential of the original scrapie isolate of sheep origin49. The development of scrapie in this primate after an incubation period compatible with its lifespan complements the study conducted in transgenic (humanized) mice; taken together these studies suggest that some isolates of sheep scrapie can promote misfolding of the human prion protein and that scrapie can develop within the lifespan of some primate species.
In addition to previous studies on scrapie transmission to primate1,8,9 and the recently published study on transgenic humanized mice13, our results constitute new evidence for recommending that the potential risk of scrapie for human health should not be dismissed. Indeed, human PrP transgenic mice and primates are the most relevant models for investigating the human transmission barrier. To what extent such models are informative for measuring the zoonotic potential of an animal TSE under field exposure conditions is unknown. During the past decades, many protective measures have been successfully implemented to protect cattle from the spread of c-BSE, and some of these measures have been extended to sheep and goats to protect from scrapie according to the principle of precaution. Since cases of c-BSE have greatly reduced in number, those protective measures are currently being challenged and relaxed in the absence of other known zoonotic animal prion disease. We recommend that risk managers should be aware of the long term potential risk to human health of at least certain scrapie isolates, notably for lymphotropic strains like the classical scrapie strain used in the current study. Relatively high amounts of infectivity in peripheral lymphoid organs in animals infected with these strains could lead to contamination of food products produced for human consumption. Efforts should also be maintained to further assess the zoonotic potential of other animal prion strains in long-term studies, notably lymphotropic strains with high prevalence like CWD, which is spreading across North America, and atypical/Nor98 scrapie (Nor98)50 that was first detected in the past two decades and now represents approximately half of all reported cases of prion diseases in small ruminants worldwide, including territories previously considered as scrapie free... 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.
Like lambs to the slaughter
* 31 March 2001 *
Debora MacKenzie *
Magazine issue 2284
Suspect symptoms
What if you can catch old-fashioned CJD by eating meat from a sheep infected with scrapie?
Exclusive from New Scientist magazine
Four years ago, Terry Singeltary watched his mother die horribly from a degenerative brain disease. Doctors told him it was Alzheimer's, but Singeltary was suspicious.
The diagnosis didn't fit her violent symptoms, and he demanded an autopsy. It showed she had died of sporadic Creutzfeldt-Jakob disease.
Photo: Murdo McLeod
Most doctors believe that sCJD is caused by a prion protein deforming by chance into a killer. But Singeltary thinks otherwise.
He is one of a number of campaigners who say that some sCJD, like the variant CJD related to BSE, is caused by eating meat from infected animals.
Their suspicions have focused on sheep carrying scrapie, a BSE-like disease that is widespread in flocks across Europe and North America.
Now scientists in France have stumbled across new evidence that adds weight to the campaigners' fears.
To their complete surprise, the researchers found that one strain of scrapie causes the same brain damage in mice as sCJD.
"This means we cannot rule out that at least some sCJD may be caused by some strains of scrapie," says team member Jean-Philippe Deslys of the French Atomic Energy Commission's medical research laboratory in Fontenay-aux-Roses, south-west of Paris.
Hans Kretschmar of the University of Göttingen, who coordinates CJD surveillance in Germany, is so concerned by the findings that he now wants to trawl back through past sCJD cases to see if any might have been caused by eating infected mutton or lamb.
Brain damage Scrapie has been around for centuries and until now there has been no evidence that it poses a risk to human health.
But if the French finding means that scrapie can cause sCJD in people, countries around the world may have overlooked a CJD crisis to rival that caused by BSE.
Deslys and colleagues were originally studying vCJD, not sCJD.
They injected the brains of macaque monkeys with brain from BSE cattle, and from French and British vCJD patients. The brain damage and clinical symptoms in the monkeys were the same for all three.
Mice injected with the original sets of brain tissue or with infected monkey brain also developed the same symptoms.
As a control experiment, the team also injected mice with brain tissue from people and animals with other prion diseases: a French case of sCJD; a French patient who caught sCJD from human-derived growth hormone; sheep with a French strain of scrapie; and mice carrying a prion derived from an American scrapie strain.
As expected, they all affected the brain in a different way from BSE and vCJD.
But while the American strain of scrapie caused different damage from sCJD, the French strain produced exactly the same pathology. Multiple strains "The main evidence that scrapie does not affect humans has been epidemiology," says Moira Bruce of the neuropathogenesis unit of the Institute for Animal Health in Edinburgh, who was a member of the same team as Deslys.
"You see about the same incidence of the disease everywhere, whether or not there are many sheep, and in countries such as New Zealand with no scrapie," she says.
In the only previous comparisons of sCJD and scrapie in mice, Bruce found they were dissimilar. But there are more than 20 strains of scrapie, and six of sCJD.
"You would not necessarily see a relationship between the two with epidemiology if only some strains affect only some people," says Deslys.
Bruce is cautious about the mouse results, but agrees they require further investigation.
Other trials of scrapie and sCJD in mice, she says, are in progress.
Deformed proteins People can have three different genetic variations of the human prion protein, and each type of protein can fold up two different ways.
Kretschmar has found that these six combinations correspond to six clinical types of sCJD: each type of normal prion produces a particular pathology when it spontaneously deforms to produce sCJD. But if these proteins deform because of infection with a disease-causing prion, the relationship between pathology and prion type should be different, as it is in vCJD.
"If we look at brain samples from sporadic CJD cases and find some that do not fit the pattern," says Kretschmar, "that could mean they were caused by infection."
There are 250 deaths per year from sCJD in the US, and a similar incidence elsewhere.
Singeltary and other US activists think that some of these people died after eating contaminated meat or "nutritional" pills containing dried animal brain.
Governments will have a hard time facing activists like Singeltary if it turns out that some sCJD isn't as spontaneous as doctors have insisted.
Deslys's work on macaques also provides further proof that the human disease vCJD is caused by BSE.
And the experiments showed that vCJD is much more virulent to primates than BSE, even when injected into the bloodstream rather than the brain. This, says Deslys, means that there is an even bigger risk than we thought that vCJD can be passed from one patient to another through contaminated blood transfusions and surgical instruments.
More at: Proceedings of the National Academy of Sciences (vol 98, p 4142)
Correspondence about this story should be directed to letters@newscientist.com 1900 GMT, 28 March 2001
* New Scientist
2001 Mar 27;98(7):4142-7. doi: 10.1073/pnas.041490898. Epub 2001 Mar 20.
Adaptation of the bovine spongiform encephalopathy agent to primates and comparison with Creutzfeldt-- Jakob disease: implications for human health
C I Lasmézas 1, J G Fournier, V Nouvel, H Boe, D Marcé, F Lamoury, N Kopp, J J Hauw, J Ironside, M Bruce, D Dormont, J P Deslys
Affiliations expand
PMID: 11259641 PMCID: PMC31193 DOI: 10.1073/pnas.041490898
Abstract
There is substantial scientific evidence to support the notion that bovine spongiform encephalopathy (BSE) has contaminated human beings, causing variant Creutzfeldt-Jakob disease (vCJD). This disease has raised concerns about the possibility of an iatrogenic secondary transmission to humans, because the biological properties of the primate-adapted BSE agent are unknown. We show that (i) BSE can be transmitted from primate to primate by intravenous route in 25 months, and (ii) an iatrogenic transmission of vCJD to humans could be readily recognized pathologically, whether it occurs by the central or peripheral route. Strain typing in mice demonstrates that the BSE agent adapts to macaques in the same way as it does to humans and confirms that the BSE agent is responsible for vCJD not only in the United Kingdom but also in France. The agent responsible for French iatrogenic growth hormone-linked CJD taken as a control is very different from vCJD but is similar to that found in one case of sporadic CJD and one sheep scrapie isolate. These data will be key in identifying the origin of human cases of prion disease, including accidental vCJD transmission, and could provide bases for vCJD risk assessment.
snip...
We found that the BSE agent in nonhuman primates is similar to that causing vCJD in humans and tends to evolve rapidly toward a primate-adapted variant. Furthermore, we showed that the strain responsible for iCJD is closely related to that of one patient with sCJD, and, more unexpectedly, that these agents were similar to the French scrapie strain studied (but different from the U.S. scrapie strain). This finding requires a cautious interpretation for several reasons, not least because of the inevitably limited number of TSE strains that can be studied by such a cumbersome method as strain typing. Nonetheless, it also prompts reconsideration of the possibility that, in some instances, sheep and human TSEs can share a common origin.
Sunday, January 10, 2021
APHIS Concurrence With OIE Risk Designation for Bovine Spongiform Encephalopathy [Docket No. APHIS-2018-0087] Singeltary Submission
June 17, 2019 APHIS
Concurrence With OIE Risk Designation for Bovine Spongiform Encephalopathy [Docket No. APHIS-2018-0087] Singeltary Submission June 17, 2019
APHIS Concurrence With OIE Risk Designation for Bovine Spongiform Encephalopathy [Docket No. APHIS-2018-0087] Singeltary Submission
Greetings APHIS et al,
I would kindly like to comment on APHIS Concurrence With OIE Risk Designation for Bovine Spongiform Encephalopathy [Docket No. APHIS-2018-0087], and my comments are as follows, with the latest peer review and transmission studies as references of evidence.
THE OIE/USDA BSE Minimal Risk Region MRR is nothing more than free pass to import and export the Transmissible Spongiform Encephalopathy TSE Prion disease. December 2003, when the USDA et al lost it's supposedly 'GOLD CARD' ie BSE FREE STATUS (that was based on nothing more than not looking and not finding BSE), once the USA lost it's gold card BSE Free status, the USDA OIE et al worked hard and fast to change the BSE Geographical Risk Statuses i.e. the BSE GBR's, and replaced it with the BSE MRR policy, the legal tool to trade mad cow type disease TSE Prion Globally. The USA is doing just what the UK did, when they shipped mad cow disease around the world, except with the BSE MRR policy, it's now legal.
Also, the whole concept of the BSE MRR policy is based on a false pretense, that atypical BSE is not transmissible, and that only typical c-BSE is transmissible via feed. This notion that atypical BSE TSE Prion is an old age cow disease that is not infectious is absolutely false, there is NO science to show this, and on the contrary, we now know that atypical BSE will transmit by ORAL ROUTES, but even much more concerning now, recent science has shown that Chronic Wasting Disease CWD TSE Prion in deer and elk which is rampant with no stopping is sight in the USA, and Scrapie TSE Prion in sheep and goat, will transmit to PIGS by oral routes, this is our worst nightmare, showing even more risk factors for the USA FDA PART 589 TSE PRION FEED ban.
The FDA PART 589 TSE PRION FEED ban has failed terribly bad, and is still failing, since August 1997. there is tonnage and tonnage of banned potential mad cow feed that went into commerce, and still is, with one decade, 10 YEARS, post August 1997 FDA PART 589 TSE PRION FEED ban, 2007, with 10,000,000 POUNDS, with REASON, Products manufactured from bulk feed containing blood meal that was cross contaminated with prohibited meat and bone meal and the labeling did not bear cautionary BSE statement. you can see all these feed ban warning letters and tonnage of mad cow feed in commerce, year after year, that is not accessible on the internet anymore like it use to be, you can see history of the FDA failure August 1997 FDA PART 589 TSE PRION FEED ban here, but remember this, we have a new outbreak of TSE Prion disease in a new livestock species, the camel, and this too is very worrisome.
WITH the OIE and the USDA et al weakening the global TSE prion surveillance, by not classifying the atypical Scrapie as TSE Prion disease, and the notion that they want to do the same thing with typical scrapie and atypical BSE, it's just not scientific.
WE MUST abolish the BSE MRR policy, go back to the BSE GBR risk assessments by country, and enhance them to include all strains of TSE Prion disease in all species. With Chronic Wasting CWD TSE Prion disease spreading in Europe, now including, Norway, Finland, Sweden, also in Korea, Canada and the USA, and the TSE Prion in Camels, the fact the the USA is feeding potentially CWD, Scrapie, BSE, typical and atypical, to other animals, and shipping both this feed and or live animals or even grains around the globe, potentially exposed or infected with the TSE Prion. this APHIS Concurrence With OIE Risk Designation for Bovine Spongiform Encephalopathy [Docket No. APHIS-2018-0087], under it's present definition, does NOT show the true risk of the TSE Prion in any country. as i said, it's nothing more than a legal tool to trade the TSE Prion around the globe, nothing but ink on paper.
AS long as the BSE MRR policy stays in effect, TSE Prion disease will continued to be bought and sold as food for both humans and animals around the globe, and the future ramifications from friendly fire there from, i.e. iatrogenic exposure and transmission there from from all of the above, should not be underestimated. ...
From: Terry S. Singeltary Sr. [flounder@wt.net]
Sent: Tuesday, July 29, 2003 1:03 PM
Cc: ggraber@cvm.fda.gov; Linda.Grassie@fda.gov; BSE-L
Subject: Docket No. 2003N-0312 Animal Feed Safety System [TSS SUBMISSION TO DOCKET 2003N-0312]
Greetings FDA,
snip...
PLUS, if the USA continues to flagrantly ignore the _documented_ science to date about the known TSEs in the USA (let alone the undocumented TSEs in cattle), it is my opinion, every other Country that is dealing with BSE/TSE should boycott the USA and demand that the SSC reclassify the USA BSE GBR II risk assessment to BSE/TSE GBR III 'IMMEDIATELY'. for the SSC to _flounder_ any longer on this issue, should also be regarded with great suspicion as well. NOT to leave out the OIE and it's terribly flawed system of disease surveillance. the OIE should make a move on CWD in the USA, and make a risk assessment on this as a threat to human health. the OIE should also change the mathematical formula for testing of disease. this (in my opinion and others) is terribly flawed as well. to think that a sample survey of 400 or so cattle in a population of 100 million, to think this will find anything, especially after seeing how many TSE tests it took Italy and other Countries to find 1 case of BSE (1 million rapid TSE test in less than 2 years, to find 102 BSE cases), should be proof enough to make drastic changes of this system. the OIE criteria for BSE Country classification and it's interpretation is very problematic. a text that is suppose to give guidelines, but is not understandable, cannot be considered satisfactory. the OIE told me 2 years ago that they were concerned with CWD, but said any changes might take years. well, two years have come and gone, and no change in relations with CWD as a human health risk. if we wait for politics and science to finally make this connection, we very well may die before any decisions or changes are made. this is not acceptable. we must take the politics and the industry out of any final decisions of the Scientific community. this has been the problem from day one with this environmental man made death sentence. some of you may think i am exaggerating, but you only have to see it once, you only have to watch a loved one die from this one time, and you will never forget, OR forgive...yes, i am still very angry... but the transmission studies DO NOT lie, only the politicians and the industry do... and they are still lying to this day...TSS
WEDNESDAY, DECEMBER 23, 2020
***> BSE research project final report 2005 to 2008 SE1796 SID5
end...TSS
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. | 3:54 PM
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