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),
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.
***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.
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X
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
Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a. Vincent Beringue c. Patricia Aguilar a,
Natalia Fernandez-Borges a. and Alba Marin-Moreno a
"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos, Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT. Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas. France
Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD) disease in human. To date, BSE agent is the only recognized zoonotic prion. Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that have been circulating for centuries in farmed ruminants there is no apparent epidemiological link between exposure to ruminant products and the occurrence of other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD). However, the zoonotic potential of the diversity of circulating TSE agents has never been systematically assessed. The major issue in experimental assessment of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the biological phenomenon that limits TSE agents’ propagation from a species to another. In the last decade, mice genetically engineered to express normal forms of the human prion protein has proved essential in studying human prions pathogenesis and modeling the capacity of TSEs to cross the human species barrier.
To assess the zoonotic potential of prions circulating in farmed ruminants, we study their transmission ability in transgenic mice expressing human PrPC (HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC (129Met or 129Val) are used to determine the role of the Met129Val dimorphism in susceptibility/resistance to the different agents.
These transmission experiments confirm the ability of BSE prions to propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be susceptible to BSE in sheep or goat to a greater degree than the BSE agent in cattle and that these agents can convey molecular properties and neuropathological indistinguishable from vCJD. However homozygous 129V mice are resistant to all tested BSE derived prions independently of the originating species suggesting a higher transmission barrier for 129V-PrP variant.
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.
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Title: Transmission of scrapie prions to primate after an extended silent incubation period
Authors
item Comoy, Emmanuel - item Mikol, Jacqueline - item Luccantoni-Freire, Sophie - item Correia, Evelyne - item Lescoutra-Etchegaray, Nathalie - item Durand, Valérie - item Dehen, Capucine - item Andreoletti, Olivier - item Casalone, Cristina - item Richt, Juergen item Greenlee, Justin item Baron, Thierry - item Benestad, Sylvie - item Hills, Bob - item Brown, Paul - item Deslys, Jean-Philippe -
Submitted to: Scientific Reports Publication Type: Peer Reviewed Journal Publication Acceptance Date: May 28, 2015 Publication Date: June 30, 2015 Citation: Comoy, E.E., Mikol, J., Luccantoni-Freire, S., Correia, E., Lescoutra-Etchegaray, N., Durand, V., Dehen, C., Andreoletti, O., Casalone, C., Richt, J.A., Greenlee, J.J., Baron, T., Benestad, S., Brown, P., Deslys, J. 2015. Transmission of scrapie prions to primate after an extended silent incubation period. Scientific Reports. 5:11573.
Interpretive Summary: The transmissible spongiform encephalopathies (also called prion diseases) are fatal neurodegenerative diseases that affect animals and humans. The agent of prion diseases is a misfolded form of the prion protein that is resistant to breakdown by the host cells. Since all mammals express prion protein on the surface of various cells such as neurons, all mammals are, in theory, capable of replicating prion diseases. One example of a prion disease, bovine spongiform encephalopathy (BSE; also called mad cow disease), has been shown to infect cattle, sheep, exotic undulates, cats, non-human primates, and humans when the new host is exposed to feeds or foods contaminated with the disease agent. The purpose of this study was to test whether non-human primates (cynomologous macaque) are susceptible to the agent of sheep scrapie. After an incubation period of approximately 10 years a macaque developed progressive clinical signs suggestive of neurologic disease. Upon postmortem examination and microscopic examination of tissues, there was a widespread distribution of lesions consistent with a transmissible spongiform encephalopathy. This information will have a scientific impact since it is the first study that demonstrates the transmission of scrapie to a non-human primate with a close genetic relationship to humans. This information is especially useful to regulatory officials and those involved with risk assessment of the potential transmission of animal prion diseases to humans. Technical Abstract: Classical bovine spongiform encephalopathy (c-BSE) is an animal prion disease that also causes variant Creutzfeldt-Jakob disease in humans. Over the past decades, c-BSE's zoonotic potential has been the driving force in establishing extensive protective measures for animal and human health.
*** 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.
Suspect symptoms
What if you can catch old-fashioned CJD by eating meat from a sheep infected with scrapie?
28 Mar 01
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...
2001
Suspect symptoms
What if you can catch old-fashioned CJD by eating meat from a sheep infected with scrapie?
28 Mar 01
Like lambs to the slaughter
31 March 2001
by Debora MacKenzie Magazine issue 2284.
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.
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.
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.
"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." 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.
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.
Then follow up with PNAS studies from which new scientist article written from;
Adaptation of the bovine spongiform encephalopathy agent to primates and comparison with Creutzfeldt- Jakob disease: Implications for human health
THE findings from Corinne Ida Lasmézas*, [dagger] , Jean-Guy Fournier*, Virginie Nouvel*,
Hermann Boe*, Domíníque Marcé*, François Lamoury*, Nicolas Kopp [Dagger] , Jean-Jacques Hauw§, James Ironside¶, Moira Bruce [||] , Dominique
Dormont*, and Jean-Philippe Deslys* et al, that 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;
CWD to CJD in humans (why not?), as easy as BSE/Scrapie;
The EMBO Journal, Vol. 19, No. 17 pp. 4425-4430, 2000
© European Molecular Biology Organization
Evidence of a molecular barrier limiting susceptibility of humans, cattle and sheep to chronic wasting disease
G.J. Raymond1, A. Bossers2, L.D. Raymond1, K.I. O?Rourke3,
L.E. McHolland4, P.K. Bryant III4, M.W. Miller5, E.S. Williams6, M. Smits2 and B. Caughey1,7 1NIAID/NIH Rocky Mountain Laboratories, Hamilton, MT 59840,
3USDA/ARS/ADRU, Pullman, WA 99164-7030, 4USDA/ARS/ABADRL,
Laramie, WY 82071, 5Colorado Division of Wildlife, Wildlife Research
Center, Fort Collins, CO 80526-2097, 6Department of Veterinary Sciences,
University of Wyoming, Laramie, WY 82070, USA and 2ID-Lelystad,
Institute for Animal Science and Health, Lelystad, The Netherlands
revised July 3, 2000; accepted July 5, 2000.
Abstract
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk, and little is known about its transmissibility to other species. An important factor controlling interspecies TSE susceptibility is prion protein (PrP) homology between the source and recipient species/genotypes. Furthermore, the efficiency with which the protease-resistant PrP (PrP-res) of one species induces the in vitro conversion of the normal PrP (PrP-sen) of another species to the protease-resistant state correlates with the cross-species transmissibility of TSE agents. Here we show that the CWD-associated PrP-res (PrPCWD) of cervids readily induces the conversion of recombinant cervid PrP-sen molecules to the protease-resistant state in accordance with the known transmissibility of CWD between cervids. In contrast, PrPCWD-induced conversions of human and bovine PrP-sen were much less efficient, and conversion of ovine PrP-sen was intermediate. These results demonstrate a barrier at the molecular level that should limit the susceptibility of these non-cervid species to CWD.
snip...
Clearly, it is premature to draw firm conclusions about CWD passing naturally into humans, cattle and sheep, but the present results suggest that CWD transmissions to humans would be as limited by PrP incompatibility as transmissions of BSE or sheep scrapie to humans. Although there is no evidence that sheep scrapie has affected humans, it is likely that BSE has caused variant CJD in 74 people (definite and probable variant CJD cases to date according to the UK CJD Surveillance Unit). Given the presumably large number of people exposed to BSE infectivity, the susceptibility of humans may still be very low compared with cattle, which would be consistent with the relatively inefficient conversion of human PrP-sen by PrPBSE. Nonetheless, since humans have apparently been infected by BSE, it would seem prudent to take reasonable measures to limit exposure of humans (as well as sheep and cattle) to CWD infectivity as has been recommended for other animal TSEs.
snip...
Scrapie to Humans USA?
1: Neuroepidemiology. 1985;4(4):240-9. Related Articles,
Sheep consumption: a possible source of spongiform encephalopathy in humans.
Davanipour Z, Alter M, Sobel E, Callahan M.
A fatal spongiform encephalopathy of sheep and goats (scrapie) shares many characteristics with Creutzfeldt-Jakob disease (CJD), a similar dementing illness of humans. To investigate the possibility that CJD is acquired by ingestion of contaminated sheep products, we collected information on production, slaughtering practices, and marketing of sheep in Pennsylvania. The study revealed that sheep were usually marketed before central nervous system signs of scrapie are expected to appear; breeds known to be susceptible to the disease were the most common breeds raised in the area; sheep were imported from other states including those with a high frequency of scrapie; use of veterinary services on the sheep farms investigated and, hence, opportunities to detect the disease were limited; sheep producers in the area knew little about scrapie despite the fact that the disease has been reported in the area, and animal organs including sheep organs were sometimes included in processed food. Therefore, it was concluded that in Pennsylvania there are some 'weak links' through which scrapie-infected animals could contaminate human food, and that consumption of these foods could perhaps account for spongiform encephalopathy in humans. The weak links observed are probably not unique to Pennsylvania.
PMID: 3915057 [PubMed - indexed for MEDLINE]
2015
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.
==============
Tuesday, December 16, 2014
*** Evidence for zoonotic potential of ovine scrapie prions
Hervé Cassard,1, n1 Juan-Maria Torres,2, n1 Caroline Lacroux,1, Jean-Yves Douet,1, Sylvie L. Benestad,3, Frédéric Lantier,4, Séverine Lugan,1, Isabelle Lantier,4, Pierrette Costes,1, Naima Aron,1, Fabienne Reine,5, Laetitia Herzog,5, Juan-Carlos Espinosa,2, Vincent Beringue5, & Olivier Andréoletti1, Affiliations Contributions Corresponding author Journal name: Nature Communications Volume: 5, Article number: 5821 DOI: doi:10.1038/ncomms6821 Received 07 August 2014 Accepted 10 November 2014 Published 16 December 2014 Article tools Citation Reprints Rights & permissions Article metrics
Abstract
Although Bovine Spongiform Encephalopathy (BSE) is the cause of variant Creutzfeldt Jakob disease (vCJD) in humans, the zoonotic potential of scrapie prions remains unknown. Mice genetically engineered to overexpress the human prion protein (tgHu) have emerged as highly relevant models for gauging the capacity of prions to transmit to humans. These models can propagate human prions without any apparent transmission barrier and have been used used to confirm the zoonotic ability of BSE. Here we show that a panel of sheep scrapie prions transmit to several tgHu mice models with an efficiency comparable to that of cattle BSE.
***The serial transmission of different scrapie isolates in these mice led to the propagation of prions that are phenotypically identical to those causing sporadic CJD (sCJD) in humans.
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
Subject terms: Biological sciences• Medical research At a glance
see more here ;
***The serial transmission of different scrapie isolates in these mice led to the propagation of prions that are phenotypically identical to those causing sporadic CJD (sCJD) in humans.***
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.***
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
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
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).
2017
***While scrapie is not known to occur in free-ranging populations of white-tailed deer, experimental cases are difficult to differentiate from CWD.
*** This work raises the potential concern that scrapie infected deer could serve as a confounding factor to scrapie eradication programs as scrapie from deer seems to be transmissible to sheep by the oronasal route.
Title: Passage of scrapie to deer results in a new phenotype upon return passage to sheep
Author
Submitted to: Prion
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2017
Publication Date: N/A
Citation: N/A
Technical Abstract: Aims: We previously demonstrated that scrapie has a 100% attack rate in white-tailed deer after either intracranial or oral inoculation. Samples from deer that developed scrapie had two different western blot patterns: samples derived from cerebrum had a banding pattern similar to the scrapie inoculum, but samples from brainstem had a banding pattern similar to CWD. In contrast, transmission of CWD from white-tailed deer to sheep by the intracranial route has a low attack rate and to-date oronasal exposure has been unsuccessful. The purpose of this study was to determine if sheep are susceptible to oronasal exposure of the scrapie agent derived from white-tailed deer. Methods: At approximately 5 months of age, Suffolk sheep of various PRNP genotypes were challenged by the oronasal route with 10% brain homogenate derived from either the cerebrum or the brainstem of scrapie-affected deer. Genotypes represented in each inoculation group were VV136RR154QQ171 (n=2), AA136RR154QQ171 (n=2), and AV136RR154QR171 (n=1). After inoculation, sheep were observed daily for clinical signs. Upon development of clinical signs, sheep were killed with an overdose of pentobarbital sodium and necropsied. Tissue samples were tested for the presence of PrPSc by EIA, western blot, and immunohistochemistry (IHC). The No. 13-7 scrapie inoculum used for the deer has a mean incubation period of 20.1 months in sheep with the AA136RR154QQ171 genotype and 26.7 months in sheep with the VV136RR154QQ171 genotype. Results: Sheep inoculated oronasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum from the cerebrum that had a scrapie-like profile. The first sheep to develop clinical signs at approximately 29 months post inoculation had the VV136RR154QQ171 genotype. Eventually sheep of the AA136RR154QQ171 genotype developed clinical signs, but at a mean incubation of 52 months. At 62 months post-inoculation, none of the sheep inoculated with material from the deer brainstem have developed clinical disease.
Conclusions: The No. 13-7 inoculum used in the original deer experiment readily infects white-tailed deer and sheep of various genotypes by the oronasal route. When inoculum is made from different brain regions of No 13-7 scrapie-infected deer from either cerebrum with a scrapie-like western blot pattern or brainstem with a CWD-like western blot pattern, sheep with the VV136RR154QQ171 genotype are the first to develop clinical signs. This is in contrast to the original No. 13-7 inoculum that has a faster incubation period in sheep with the AA136RR154QQ171 genotype. Similar to experiments conducted with CWD, sheep oronasally inoculated with brainstem material from deer with a CWD-like molecular profile have no evidence of disease after 62 months of incubation. While scrapie is not known to occur in free-ranging populations of white-tailed deer, experimental cases are difficult to differentiate from CWD. This work raises the potential concern that scrapie infected deer could serve as a confounding factor to scrapie eradication programs as scrapie from deer seems to be transmissible to sheep by the oronasal route.
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