Zoonotic Potential of Chronic Wasting Disease After Adaptation in Intermediate Species
Volume 30, Number 12—December 2024
Research Letter
Zoonotic Potential of Chronic Wasting Disease After Adaptation in Intermediate Species
Tomás BarrioComments to Author , Sylvie L. Benestad, Jean-Yves Douet, Alvina Huor, Séverine Lugan, Naïma Aron, Hervé Cassard, Juan Carlos Espinosa, Alicia Otero, Rosa Bolea, Juan María Torres, and Olivier Andréolett
Author affiliation: Unité Mixte de Recherche de l’Institut National de Recherche pour l’Agriculture, l’Alimentation, et l’Environnement 1225 Interactions Hôtes-Agents Pathogènes, École Nationale Vétérinaire de Toulouse, Toulouse, France (T. Barrio, J.-Y. Douet, A. Huor, S. Lugan, N. Aron, H. Cassard, O. Andréoletti); Norwegian Veterinary Institute, Ås, Norway (S.L. Benestad); Consejo Superior de Investigaciones Científicas, Madrid, Spain (J.C. Espinosa, J.M. Torres); Universidad de Zaragoza, Zaragoza, Spain (A. Otero, R. Bolea)
Abstract
Chronic wasting disease (CWD) is an emerging disease in Europe. We report an increase in interspecies transmission capacity and zoonotic potential of a moose CWD isolate from Europe after passage in an ovine prion protein–expressing host. Those results indicated some CWD prions could acquire enhanced zoonotic properties following adaptation in an intermediate species.
Chronic wasting disease (CWD) is a highly contagious prion disease affecting members of the Cervidae family. CWD is widely spread across North America, where it endangers the survival of free-ranging cervid populations. In Europe, CWD was reported in a reindeer (Rangifer tarandus tarandus) from Norway in 2016 (1). Since 2016, several cases have been reported in Norway, Sweden, and Finland in multiple species, including reindeer, red deer (Cervus elaphus), and moose (Alces alces) (2).
Whereas CWD strains circulating in North America exhibit some uniformity (3), the cases found in Europe are more variable. Transmission into rodent models has revealed multiple CWD strains that are apparently different than strains in North America, and moose cases in Norway have demonstrated biochemical patterns distinct from previous cases in Europe (4). We characterized the interspecies transmission potential of 1 moose CWD isolate from Norway (Norwegian Veterinary Institute identification no. 16–60-P153) (4) by intracerebral injection of mouse models expressing the normal prion protein (PrPC) sequences from several species (Figure, panel A).
We anesthetized and inoculated 6–10-week-old mice with 2 mg of equivalent tissue (20 µL of 10% brain homogenate) in the right parietal lobe. We monitored the inoculated animals daily and humanely euthanized animals at the onset of clinical signs or after the preestablished endpoint of 700 days postinfection (dpi). We conducted a systematic proteinase K–resistant prion protein (PrPres) detection by using Western blot.
Inoculation of the original CWD isolate did not cause the propagation of detectable prions in Tg340 mice expressing methionine (TgMet) or Tg361 mice expressing valine (TgVal) at position 129 of human PrPC. We did not observe PrPres in brain tissue or disease occurrence in bovine PrPC-expressing mice (BoTg110) after intracerebral inoculation of the CWD isolate (Table; Figure, panel B).
We inoculated the CWD isolate in Tg338 mice, which overexpress ovine PrP ≈8 times. At 612 and 717 dpi (Table), 2 of 12 animals showed clinical signs of prion disease and we detected PrPres accumulation in their brain tissue (Figure, panel B). Of note, the 2 animals showed different PrPres banding patterns, with the nonglycosylated band migrating to 19 kDa in the first mouse and to 21 kDa in the second. Both PrPres-containing brains transmitted disease with 100% efficacy to second-passage Tg338mice, which contained 21-kDa PrPres in their brains (Figure, panel B). A third passage resulted in the incubation period shortening (95 ± 5 dpi). Our observations are consistent with a progressive adaptation of the moose CWD prion to the ovine-PrPC expressing model and suggest moose CWD prions in Europe may have an intrinsic capability to propagate in ovine species with the VRQ genotype.
We next determined whether adaptation of this moose CWD agent to Tg338 altered its capacity to cross species barriers. For that purpose, we inoculated Tg338-adapted moose CWD prions (passaged twice in Tg338) to the same panel of PrPC-expressing mice models. Inoculation of the Tg338-adapted isolate to BoTg110 resulted in 100% disease transmission that showed a banding pattern and intermediate molecular weight from 19–21 kDa (Figure, panel C; Appendix Figure) and an incubation period of 431 ± 32 dpi (Table), which suggested the lack of a major transmission barrier. In addition, 1 of 8 inoculated TgMet mice showed clinical signs at 561 dpi (Table). PrPres in the brain of that mouse was revealed by a mixed 19 + 21 kDa banding pattern (Figure, panel C). A second passage in TgMet is underway.
Inoculation of TgVal resulted in efficient transmission (5/6 animals); the mean incubation period was 483 ± 35 dpi (Table) and accumulation was 21 kDa PrPres (Figure, panel C). On second passage, transmission was 100% and we observed a shorter incubation period (311 ± 12 dpi).
The incubation periods and PrPres biochemical profiles of the CWD prions that propagated in the TgMet and TgVal mice greatly differed from those observed in mice inoculated with the most prevalent human prion strains or with classic bovine spongiform encephalopathy (BSE), sheep-adapted BSE, or Tg338-adapted c-BSE (Table; Figure, panel D). Those results might suggest this CWD-derived prion strain differs from other strains documented in those models. Further investigation is necessary.
The evolution of moose CWD zoonotic potential after its passage in an ovine PrPC-expressing host is reminiscent of the well-documented altered capacities of the c-BSE agent to cross the human species barrier after adaptation in sheep and goats (9). The codon 129-dependent response to infection of humanized mice with Tg338-adapted CWD is also compatible with studies demonstrating the role of this polymorphism in susceptibility to prions (10).
In summary, our results demonstrate the potential capacity of some CWD agents to transmit to sheep or other farmed animals. Our results highlight the need to experimentally assess and monitor this transmission risk under natural exposure conditions. In addition, the dramatic changes of the zoonotic capacity of the CWD isolate we documented from Europe clearly demonstrate the risk adaptation and propagation of cervid prions into farmed animals represents. Although additional studies are needed to characterize these emerging agents, our findings have major potential implications for animal and public health.
Dr. Barrio is a research scientist with Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement. His research interests include animal and human prion diseases and other neurodegenerative disorders linked to misfolded proteins.
https://wwwnc.cdc.gov/eid/article/30/12/24-0536_article
Transmission of the chronic wasting disease agent from elk to cattle after oronasal exposure
Justin Greenlee, Jifeng Bian, Zoe Lambert, Alexis Frese, and Eric Cassmann Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
Aims: The purpose of this study was to determine the susceptibility of cattle to chronic wasting disease agent from elk.
Materials and Methods: Initial studies were conducted in bovinized mice using inoculum derived from elk with various genotypes at codon 132 (MM, LM, LL). Based upon attack rates, inoculum (10% w/v brain homogenate) from an LM132 elk was selected for transmission studies in cattle. At approximately 2 weeks of age, one wild type steer (EE211) and one steer with the E211K polymorphism (EK211) were fed 1 mL of brain homogenate in a quart of milk replacer while another 1 mL was instilled intranasally. The cattle were examined daily for clinical signs for the duration of the experiment. One steer is still under observation at 71 months post-inoculation (mpi).
Results: Inoculum derived from MM132 elk resulted in similar attack rates and incubation periods in mice expressing wild type or K211 bovine PRNP, 35% at 531 days post inoculation (dpi) and 27% at 448 dpi, respectively. Inoculum from LM132 elk had a slightly higher attack rates in mice: 45% (693 dpi) in wild type cattle PRNP and 33% (468) in K211 mice. Inoculum from LL132 elk resulted in the highest attack rate in wild type bovinized mice (53% at 625 dpi), but no K211 mice were affected at >700 days. At approximately 70 mpi, the EK211 genotype steer developed clinical signs suggestive of prion disease, depression, low head carriage, hypersalivation, and ataxia, and was necropsied. Enzyme immunoassay (IDEXX) was positive in brainstem (OD=4.00, but non-detect in retropharyngeal lymph nodes and palatine tonsil. Immunoreactivity was largely limited to the brainstem, midbrain, and cervical spinal cord with a pattern that was primarily glia-associated.
Conclusions: Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material.
Funded by: This research was funded in its entirety by congressionally appropriated funds to the United States Department of Agriculture, Agricultural Research Service. The funders of the work did not influence study design, data collection and analysis, decision to publish, or preparation of the manuscript.
"Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material."
=====end
Strain characterization of chronic wasting disease in bovine-PrP transgenic mice
Nuria Jerez-Garrido1, Sara Canoyra1, Natalia Fernández-Borges1, Alba Marín Moreno1, Sylvie L. Benestad2, Olivier Andreoletti3, Gordon Mitchell4, Aru Balachandran4, Juan María Torres1 and Juan Carlos Espinosa1. 1 Centro de Investigación en Sanidad Animal, CISA-INIA-CSIC, Madrid, Spain. 2 Norwegian Veterinary Institute, Ås, Norway. 3 UMR Institut National de la Recherche Agronomique (INRA)/École Nationale Vétérinaire de Toulouse (ENVT), Interactions Hôtes Agents Pathogènes, Toulouse, France. 4 Canadian Food Inspection Agency, Ottawa, Canada.
Aims: Chronic wasting disease (CWD) is an infectious prion disease that affects cervids. Various CWD prion strains have been identified in different cervid species from North America and Europe. The properties of the infectious prion strains are influenced by amino acid changes and polymorphisms in the PrP sequences of different cervid species. This study, aimed to assess the ability of a panel of CWD prion isolates from diverse cervid species from North America and Europe to infect bovine species, as well as to investigate the properties of the prion strains following the adaptation to the bovine-PrP context.
Materials and Methods: BoPrP-Tg110 mice overexpressing the bovine-PrP sequence were inoculated by intracranial route with a panel of CWD prion isolates from both North America (two white-tailed deer and two elk) and Europe (one reindeer, one moose and one red deer).
Results: Our results show distinct behaviours in the transmission of the CWD isolates to the BoPrP-Tg110 mouse model. Some of these isolates did not transmit even after the second passage. Those able to transmit displayed differences in terms of attack rate, survival times, biochemical properties of brain PrPres, and histopathology.
Conclusions: Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study.
Funded by: MCIN/AEI /10.13039/501100011033 and by European Union NextGeneration EU/PRTR
Grant number: PCI2020-120680-2 ICRAD
"Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study."
=====end
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
Transmission of the chronic wasting disease agent from elk to cattle after oronasal exposure
Price of TSE Prion Poker goes up substantially, all you cattle ranchers and such, better pay close attention here...
https://chronic-wasting-disease.blogspot.com/2023/10/transmission-of-chronic-wasting-disease.html
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=313160
***Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
Even if the prevailing view is that sporadic CJD is due to the spontaneous formation of CJD prions, it remains possible that its apparent sporadic nature may, at least in part, result from our limited capacity to identify an environmental origin.
https://www.nature.com/articles/srep11573
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases.
==============
PRION 2015 CONFERENCE
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019500/
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 1933-690X
WS-01: Prion diseases in animals and zoonotic potential
Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
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
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
http://www.nature.com/ncomms/2014/141216/ncomms6821/full/ncomms6821.html
snip... R. BRADLEY
http://collections.europarchive.org/tna/20080102222950/http://www.bseinquiry.gov.uk/files/yb/1990/09/23001001.pdf
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
http://web.archive.org/web/20010305223125/www.bseinquiry.gov.uk/files/yb/1976/10/12004001.pdf
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).
http://www.nature.com/nature/journal/v236/n5341/abs/236073a0.html
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
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.
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353091
https://www.ars.usda.gov/research/publications/publication/?seqNo115=337105
EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY
LINE TO TAKE
3. If questions on pharmaceuticals are raised at the Press conference, the suggested line to take is as follows:-
"There are no medicinal products licensed for use on the market which make use of UK-derived porcine tissues with which any hypothetical “high risk" ‘might be associated. The results of the recent experimental work at the CSM will be carefully examined by the CSM‘s Working Group on spongiform encephalopathy at its next meeting.
DO Hagger RM 1533 MT Ext 3201
http://web.archive.org/web/20030822054419/www.bseinquiry.gov.uk/files/yb/1990/09/21009001.pdf
http://web.archive.org/web/20031026000118/www.bseinquiry.gov.uk/files/yb/1990/08/23004001.pdf
http://web.archive.org/web/20030822031154/www.bseinquiry.gov.uk/files/yb/1990/09/10007001.pdf
http://web.archive.org/web/20030822052332/www.bseinquiry.gov.uk/files/yb/1990/09/11005001.pdf
http://web.archive.org/web/20030822052438/www.bseinquiry.gov.uk/files/yb/1990/09/12002001.pdf
http://web.archive.org/web/20030822054419/www.bseinquiry.gov.uk/files/yb/1990/09/21009001.pdf
https://www.agriculture.arkansas.gov/wp-content/uploads/2020/05/Moore_2017_Swine_CWD.pdf
* Marina Betancor, Belén Marín, Alicia Otero, Carlos Hedman, Antonio Romero, Tomás Barrio, Eloisa Sevilla, Jean-Yves Douet, Alvina Huor, Juan José Badiola, Olivier Andréoletti & Rosa Bolea
* Veterinary Research volume 54, Article number: 89 (2023)
Abstract
The emergence of bovine spongiform encephalopathy (BSE) prions from atypical scrapie has been recently observed upon experimental transmission to rodent and swine models. This study aimed to assess whether the inoculation of atypical scrapie could induce BSE-like disease in cattle. Four calves were intracerebrally challenged with atypical scrapie. Animals were euthanized without clinical signs of prion disease and tested negative for PrPSc accumulation by immunohistochemistry and western blotting. However, an emergence of BSE-like prion seeding activity was detected during in vitro propagation of brain samples from the inoculated animals. These findings suggest that atypical scrapie may represent a potential source of BSE infection in cattle.
Snip…
Further in vivo experiments challenging different mouse lines have been started in order to confirm the infectivity of the PMCA products obtained in this study. However, in conclusion, our findings show that the propagation of atypical scrapie in cattle leads to the emergence of BSE-like seeding activity. This is a concerning issue with far-reaching implications for public health and food safety. The possibility of interspecies transmission of prion diseases and the emergence of new prion strains highlight the critical need for continued surveillance and monitoring of these diseases in both animal and human populations. Early detection of prion diseases is crucial, and highly sensitive detection techniques such as PMCA can play an important role in this regard.
https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-023-01225-2
Christina M. Carlson 15 Samuel Thomas 9, 15 Matthew W. Keating 10 Rodrigo Morales Christopher J. Johnson 14, 17 Joel A. Pedersen 16 Show all authors Show footnotes Open AccessPublished:November 09, 2023 DOI: https://doi.org/10.1016/j.isci.2023.108428
Advertisement Highlights
• Abnormal prion protein can enter the roots of plants
• Plants can translocate detectable levels of prions to aerial tissues
•Animals exposed to prion-contaminated plant tissues can acquire disease
•Contaminated plants may represent a route of prion exposure Summary
Prions cause fatal neurodegenerative diseases and exhibit remarkable durability, which engenders a wide array of potential exposure scenarios. In chronic wasting disease of deer, elk, moose, and reindeer and in scrapie of sheep and goats, prions are transmitted via environmental routes and the ability of plants to accumulate and subsequently transmit prions has been hypothesized, but not previously demonstrated. Here, we establish the ability of several crop and other plant species to take up prions via their roots and translocate them to above-ground tissues from various growth media including soils. We demonstrate that plants can accumulate prions in above-ground tissues to levels sufficient to transmit disease after oral ingestion by mice. Our results suggest plants may serve as vectors for prion transmission in the environment—a finding with implications for wildlife conservation, agriculture, and public health.
Snip…
Discussion
We examined whether plants could serve as vectors for prion diseases by experimentally investigating the complete process: root uptake, translocation, and subsequently transmission of prions via the environmentally relevant oral route. Others have provided evidence for some of these steps (viz. uptake via roots and translocation of PrPTSE by barley and oral transmission after external contamination of plants with high concentrations of prions26), but the question of whether plants grown in contaminated media could accumulate sufficient amounts of prions in aerial tissues to serve as environmental vectors of prion diseases remained unanswered. Here, we have shown that plants can take up, translocate, accumulate, and deliver enough prions to infect mice via the oral route of exposure.
It is important to note the present study was conducted using carefully controlled laboratory models of environmental prion uptake and transmission and future efforts to study such processes at field scale in larger animals are certainly warranted. Aspects of these experiments that do not faithfully recapitulate the diseases they model include animal digestive tract structure (viz. mouse versus ruminant), prion strain (viz. lab animal-adapted strains versus authentic stains), and the means by which infectious prions were introduced to plants (e.g., extent of infected material degradation). Nonetheless, we expect the present models do offer key insights into likely behavior in the environment. For example, while the minimum infectious dose of prions in plants should certainly be examined under environmentally relevant conditions, a vanishingly small amount—as little as 300 ng of CWD-infected brain material—is sufficient to infect white-tailed deer when delivered orally.36 Additionally, the duration of prion exposure, to both plants and subsequently mice, was transient and compressed here relative to scenarios relevant to the environment or to animal husbandry. Wild plants and crops could accumulate prions over longer periods of time from contaminated soils and serve as vectors for exposure over the lifetime of deer and other animals. Environmental exposures would involve repeated, intermittent intake, which is likely to increase disease incidence relative to a single ingestion event.37
At present, our ability to characterize the risk of plants as vectors for prion transmission is impeded by the lack of quantitative information on prion uptake, distribution, metabolism, and excretion in both plants and animals. Nonetheless, our finding of accumulation of two prion strains by a variety of plants grown hydroponically, in agar, or on soil supports the potential for plants to acquire CWD, scrapie, or other prions from the environment and transmit prion disease to susceptible hosts, making plants a plausible vector for prion diseases in wildlife, livestock, and humans. The potential for plants to serve as vectors for prion disease has implications for the disposal of infected carcasses, grazing practices, and the use and transport of potentially contaminated crop materials.
https://www.cell.com/iscience/pdf/S2589-0042(23)02505-1.pdf
Paulina Soto1,2, Francisca Bravo-Risi1,2, Claudio Soto1, Rodrigo Morales1,2 1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease is a prion disease affecting cervids captive and free-range. CWD is thought to be caused by indirect exposure to contaminated environments. Many studies have shown that infectious prions can enter the environment through saliva, feces, or urine from infected animals and decaying carcasses. However, we need to understand the specific contribution of this componenit to disease transmission events. Plants are logical environmental components to be evaluated since they grow in environments contaminated with CWD prions and are relevant for transmission. The main objective of this study is to characterize whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait. We have grown carrot plants in CWD-infected soils. We harvested the carrots and separated them from the leaves. These materials were interrogated for their prion seeding activity using the PMCA. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions and in carrot plants (leaves and roots) grown on them. Bioassays showed that both plants and roots contained CWD prions sufficiently to induce disease. As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts. Our results indicate that edible plants could participate as vectors of CWD transmission.
Regulation No. 1599 of 2018 on additional requirements for the import of hay and straw for used for animal feed.
This content is exclusively provided by
FAO, FAOLEX
Regulation No. 1599 of 2018 on additional requirements for the import of hay and straw for used for animal feed.
Country Norway
Type of law Regulation
Source
FAO , FAOLEX
Abstract
This Regulation seeks to prevent the spread of infectious animal diseases that can be caused by the importation of hay and straw used in animal feed from countries outside the European Economic Area. Hay and straw imported into Norway as animal feed must: (a) be accompanied by a confirmation from the manufacturer that the product has been stored for at least two months in the country of dispatch and harvested from farms where no animal manure has been fertilized during the past two years; and b) be accompanied by a certificate from a public veterinarian in the country of dispatch that the product has been harvested from farms where no restrictions have been set due to infectious animal disease. In addition, hay and straw from the United States and Canada must be accompanied by a certificate from a public veterinarian that the product has been harvested in states or provinces where Chronic Wasting Disease has not been detected on deer.
Attached files
http://faolex.fao.org/docs/pdf/nor189761.pdf
Date of text
22 Oct 2018
Repealed
No
Source language
English
Legislation Amendment
No
Original title
Forskrift om tilleggskrav ved import av høy og halm til dyrefôr.
Amends
Regulation prohibiting the importation of animals and infectious objects. on 22 Oct 2018
https://leap.unep.org/countries/no/national-legislation/regulation-no-1599-2018-additional-requirements-import-hay-and
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 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.....
https://web.archive.org/web/20170404125557/http://webarchive.nationalarchives.gov.uk/20130822084033/http://www.defra.gov.uk/animal-diseases/files/qra_chronic-wasting-disease-121029.pdf
Christopher Johnson1, Christina Carlson1, Matthew Keating1,2, Nicole Gibbs1, Haeyoon Chang1, Jamie Wiepz1, and Joel Pedersen1 1USGS National Wildlife Health Center; Madison, WI USA; 2University of Wisconsin - Madison; Madison, WI USA
Soil may preserve chronic wasting disease (CWD) and scrapie infectivity in the environment, making consumption or inhalation of soil particles a plausible mechanism whereby na€ıve animals can be exposed to prions. Plants are known to absorb a variety of substances from soil, including whole proteins, yet the potential for plants to take up abnormal prion protein (PrPTSE) and preserve prion infectivity is not known. In this study, we assessed PrPTSE uptake into roots using laser scanning confocal microscopy with fluorescently tagged PrPTSE and we used serial protein misfolding cyclic amplification (sPMCA) and detect and quantify PrPTSE levels in plant aerial tissues. Fluorescence was identified in the root hairs of the model plant Arabidopsis thaliana, as well as the crop plants alfalfa (Medicago sativa), barley (Hordeum vulgare) and tomato (Solanum lycopersicum) upon exposure to tagged PrPTSE but not a tagged control preparation. Using sPMCA, we found evidence of PrPTSE in aerial tissues of A. thaliana, alfalfa and maize (Zea mays) grown in hydroponic cultures in which only roots were exposed to PrPTSE. Levels of PrPTSE in plant aerial tissues ranged from approximately 4 £ 10 ¡10 to 1 £ 10 ¡9 g PrPTSE g ¡1 plant dry weight or 2 £ 105 to 7 £ 106 intracerebral ID50 units g ¡1 plant dry weight. Both stems and leaves of A. thaliana grown in culture media containing prions are infectious when intracerebrally-injected into mice.
***Our results suggest that prions can be taken up by plants and that contaminated plants may represent a previously unrecognized risk of human, domestic species and wildlife exposure to prions.
===========
***Our results suggest that prions can be taken up by plants and that contaminated plants may represent a previously unrecognized risk of human, domestic species and wildlife exposure to prions.
*** SEE ;
Friday, May 15, 2015
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions Report
http://transmissiblespongiformencephalopathy.blogspot.com/2015/05/grass-plants-bind-retain-uptake-and.html
0 Comments:
Post a Comment
Subscribe to Post Comments [Atom]
<< Home