CWD TSE PRION CERVID ENVIRONMENTAL RISK FACTORS 2023
CWD TSE PRION CERVID ENVIRONMENTAL RISK FACTORS 2023
"Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation."
Detection of prions in soils contaminated by multiple routes
Stuart Siegfried Lichtenberg1,2 , Heather Inzalaco3 , Sam Thomas4 , Dan Storm5 , Dan Walsh6
1Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, U.S.A. 2Minnesota Center for Prion Research and Outreach, University of Minnesota, St. Paul, Minnesota, U.S.A. 3 Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, U.S.A 4Department of Soil Science, University of Wisconsin-Madison, Madison, Wisconsin, U.S.A. 5Wisconsin Department of Natural Resources, Eau Claire, Wisconsin, U.S.A. 6U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, Montana, U.S.A.
Aims: Free-ranging animals afflicted with transmissible spongiform encephalopathies frequently shed infectious prions into the broader environment. The quintessential example is chronic wasting disease, the TSE of cervids. Over the course of the disease, an infected animal will shed infectious prions in blood, urine, saliva, and feces. Upon death, the total prion load interred in the animal’s tissues will be deposited wherever the animal falls. This contamination creates substantial risk to naïve animals, and likely contributes to disease spread. Identification and quantification of prions at contamination hotspots is essential for any attempt at mitigation of environmental transmission.
Materials and Methods: Surfactant extraction of soils followed by precipitation yields a sample that is amenable to analysis by real-time quaking induced conversion. However, differences in extraction yield are apparent depending on the properties of the matrix from which the prions are being extracted, principally soil clay content.
Results: We are able to detect prion seeding activity at multiple types of environmental hotspots, including carcass sites, contaminated captive facilities, and scrapes (i.e. urine and saliva). Differences in relative prion concentration vary depending on the nature and source of the contamination.
Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation.
Conclusions: Detection of prions in the environment is of the utmost importance for controlling chronic wasting disease spread. Here, we have demonstrated a viable method for detection of prions in complex environmental matrices. However, it is quite likely that this method underestimates the total infectious prion load in a contaminated sample, due to incomplete recovery of infectious prions. Further refinements are necessary for accurate quantification of prions in such samples, and to account for the intrinsic heterogeneities found in the broader environment.
Funded by: Wisconsin Department of Natural Resources
"Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation."
=====end
The detection and decontamination of chronic wasting disease prions during venison processing
Marissa S. Milstein1,2, Marc D. Schwabenlander1,2, Sarah C. Gresch1,2, Manci Li1,2, Stuart Lichtenberg1,2, Rachel Shoemaker1,2, Gage R. Rowden1,2, Jason C. Bartz2,3 , Tiffany M. Wolf2,4, Peter A. Larsen1,2
Presenting author: Tiffany M. Wolf 1 Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA 2 Minnesota Center for Prion Research and Outreach, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA 3 Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska, USA 4 Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA
Aims: There is a growing concern that chronic wasting disease (CWD) prions in venison pose a risk to human health. CWD prions accumulate in infected deer tissues that commonly enter the human food chain through meat processing and consumption. The United States (US) Food and Drug Administration and US Department of Agriculture now formally consider CWD-positive venison unfit for human and animal consumption. Yet, the degree to which prion contamination occurs during routine venison processing is unknown. Here, we use environmental surface swab methods to: a) experimentally test meat processing equipment (i.e., stainless steel knives and polyethylene cutting boards) before and after processing CWD-positive venison and b) test the efficacy of five different disinfectant types (i.e., Dawn dish soap, Virkon-S, Briotech, 10% bleach, and 40% bleach) to determine prion decontamination efficacy.
Materials and Methods: We used a real-time quaking-induced conversion (RT-QuIC) assay to determine CWD infection status of venison and to detect CWD prions in the swabs. We collected three swabs per surface and ran eight technical replicates on RT-QuIC.
Results: CWD prions were detected on all cutting boards (n= 3; replicates= 8/8, 8/8, 8/8 and knives (n= 3; replicates= 8/8, 8/8, 8/8) used in processing CWD-positive venison, but not on those used for CWD-negative venison. After processing CWD-positive venison, allowing the surfaces to dry, and washing the cutting board with Dawn dish soap, we detected CWD prions on the cutting board surface (n= 3; replicates= 8/8, 8/8, 8/8) but not on the knife (n= 3, replicates = 0/8, 0/8, 0/8). Similar patterns were observed with Briotech (cutting board: n= 3; replicates= 7/8, 1/8, 0/8; knife: n= 3; replicates = 0/8, 0/8, 0/8). We did not detect CWD prions on the knives or cutting boards after disinfecting with Virkon-S, 10% bleach, and 40% bleach.
Conclusions: These preliminary results suggest that Dawn dish soap and Briotech do not reliably decontaminate CWD prions from these surfaces. Our data suggest that Virkon-S and various bleach concentrations are more effective in reducing prion contamination of meat processing surfaces; however, surface type may also influence the ability of prions to adsorb to surfaces, preventing complete decontamination. Our results will directly inform best practices to prevent the introduction of CWD prions into the human food chain during venison processing.
Acknowledgement: Funding was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR), the Rapid Agriculture Response Fund (#95385/RR257), and the Michigan Department of Natural Resources.
Theme: Animal prion diseases
=====end
Prion 2023 Abstracts
***> Infectious agent of sheep scrapie may persist in the environment for at least 16 years
***> Nine of these recurrences occurred 14–21 years after culling, apparently as the result of environmental contamination, but outside entry could not always be absolutely excluded.
JOURNAL OF GENERAL VIROLOGY Volume 87, Issue 12
Infectious agent of sheep scrapie may persist in the environment for at least 16 years Free
Rapid recontamination of a farm building occurs after attempted prion removal
First published: 19 January 2019 https://doi.org/10.1136/vr.105054
The data illustrates the difficulty in decontaminating farm buildings from scrapie, and demonstrates the likely contribution of farm dust to the recontamination of these environments to levels that are capable of causing disease.
snip...
This study clearly demonstrates the difficulty in removing scrapie infectivity from the farm environment. Practical and effective prion decontamination methods are still urgently required for decontamination of scrapie infectivity from farms that have had cases of scrapie and this is particularly relevant for scrapiepositive goatherds, which currently have limited genetic resistance to scrapie within commercial breeds.24 This is very likely to have parallels with control efforts for CWD in cervids.
***>This is very likely to have parallels with control efforts for CWD in cervids.
Front. Vet. Sci., 14 September 2015 | https://doi.org/10.3389/fvets.2015.00032
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination.
172. Establishment of PrPCWD extraction and detection methods in the farm soil
Conclusions: Our studies showed that PrPCWD persist in 0.001% CWD contaminated soil for at least 4 year and natural CWD-affected farm soil. When cervid reintroduced into CWD outbreak farm, the strict decontamination procedures of the infectious agent should be performed in the environment of CWD-affected cervid habitat.
SUBJECT MATTER: Chronic Wasting Disease Carcass Disposal Dumpster Management and Biosecurity
BACKGROUND INFORMATION:
State and tribal wildlife agencies may identify collection points (dumpsters) within an identified chronic wasting disease (CWD) management zone for the disposal of hunter-harvested cervid carcasses to remove potentially infected carcasses off the landscape for disposal by an approved method (Gillin & Mawdsley, 2018, chap.14). However, depending on their placement and maintenance these dumpsters could potentially increase the risk of CWD transmission.
In several different states, photographic evidence has shown dumpsters in state identified CWD management zones overflowing with deer carcasses and limbs scattered on the land nearby. This could provide an opportunity for scavengers to potentially move infected carcass material to non-infected zones or increase contamination of the ground material around the dumpster’s location.
Federal guidance does not explicitly address uniform standards for collection locations for carcasses of free-ranging cervids; however, the United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services Program Standards on CWD outlines procedures for carcass disposal, equipment sanitation, and decontamination of premises for captive cervid facilities.
RESOLUTION:
The United States Animal Health Association urges the Association of Fish and Wildlife Agencies (AFWA), Wildlife Health Committee to further refine the AFWA Technical Report on Best Management Practices for Prevention, Surveillance, and Management of Chronic Wasting Disease; Chapter 14, Carcass Disposal to address the placement and management of chronic wasting disease carcass disposal dumpsters or other carcass collection containers.
Reference:
1. Gillin, Colin M., and Mawdsley, Jonathan R. (eds.). 2018. AFWA Technical Report on Best Management Practices for Surveillance, Management and Control of Chronic Wasting Disease. Association of Fish and Wildlife Agencies, Washington, D. C. 111 pp.
THE tse prion aka mad cow type disease is not your normal pathogen.
The TSE prion disease survives ashing to 600 degrees celsius, that’s around 1112 degrees farenheit.
you cannot cook the TSE prion disease out of meat.
you can take the ash and mix it with saline and inject that ash into a mouse, and the mouse will go down with TSE.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production as well.
the TSE prion agent also survives Simulated Wastewater Treatment Processes.
IN fact, you should also know that the TSE Prion agent will survive in the environment for years, if not decades.
you can bury it and it will not go away.
The TSE agent is capable of infected your water table i.e. Detection of protease-resistant cervid prion protein in water from a CWD-endemic area.
it’s not your ordinary pathogen you can just cook it out and be done with.
***> that’s what’s so worrisome about Iatrogenic mode of transmission, a simple autoclave will not kill this TSE prion agent. I’m thinking tools used to dress a deer, knives with wooden handles, carcass disposal, burial only 3ft, scavengers, exposure of Cwd to soil and surrounding area, plants intake, …I could go on…Terry
1: J Neurol Neurosurg Psychiatry 1994 Jun;57(6):757-8
***> Transmission of Creutzfeldt-Jakob disease to a chimpanzee by electrodes contaminated during neurosurgery.
Gibbs CJ Jr, Asher DM, Kobrine A, Amyx HL, Sulima MP, Gajdusek DC.
Laboratory of Central Nervous System Studies, National Institute of
Neurological Disorders and Stroke, National Institutes of Health,
Bethesda, MD 20892.
Stereotactic multicontact electrodes used to probe the cerebral cortex of a middle aged woman with progressive dementia were previously implicated in the accidental transmission of Creutzfeldt-Jakob disease (CJD) to two younger patients. The diagnoses of CJD have been confirmed for all three cases. More than two years after their last use in humans, after three cleanings and repeated sterilisation in ethanol and formaldehyde vapour, the electrodes were implanted in the cortex of a chimpanzee. Eighteen months later the animal became ill with CJD. This finding serves to re-emphasise the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them.
PMID: 8006664 [PubMed - indexed for MEDLINE]
New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production
Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing
Rapid assessment of bovine spongiform encephalopathy prion inactivation by heat treatment in yellow grease produced in the industrial manufacturing process of meat and bone meals
THURSDAY, FEBRUARY 28, 2019
BSE infectivity survives burial for five years with only limited spread
5 or 6 years quarantine is NOT LONG ENOUGH FOR CWD TSE PRION !!!
QUARANTINE NEEDS TO BE 21 YEARS FOR CWD TSE PRION !
You can take this communication from my old files with how ever many grains of salt you wish…Terry
FRIDAY, APRIL 30, 2021
Should Property Evaluations Contain Scrapie, CWD, TSE PRION Environmental Contamination of the land?
***> Confidential!!!!
***> As early as 1992-3 there had been long studies conducted on small pastures containing scrapie infected sheep at the sheep research station associated with the Neuropathogenesis Unit in Edinburgh, Scotland. Whether these are documented...I don't know. But personal recounts both heard and recorded in a daily journal indicate that leaving the pastures free and replacing the topsoil completely at least 2 feet of thickness each year for SEVEN years....and then when very clean (proven scrapie free) sheep were placed on these small pastures.... the new sheep also broke out with scrapie and passed it to offspring. I am not sure that TSE contaminated ground could ever be free of the agent!! A very frightening revelation!!!
---end personal email early BSE days---end...tss
and so it seems...
Scrapie Agent (Strain 263K) Can Transmit Disease via the Oral Route after Persistence in Soil over Years
Published: May 9, 2007
snip...
Our results showed that 263K scrapie agent can persist in soil at least over 29 months. Strikingly, not only the contaminated soil itself retained high levels of infectivity, as evidenced by oral administration to Syrian hamsters, but also feeding of aqueous soil extracts was able to induce disease in the reporter animals. We could also demonstrate that PrPSc in soil, extracted after 21 months, provides a catalytically active seed in the protein misfolding cyclic amplification (PMCA) reaction. PMCA opens therefore a perspective for considerably improving the detectability of prions in soil samples from the field.
snip...
Dr. Paul Brown Scrapie Soil Test BSE Inquiry Document
Trucking CWD TSE PrP
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...
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...
http://webarchive.nationa...
Published: 06 September 2021
***> Chronic wasting disease: a cervid prion infection looming to spillover
Alicia Otero, Camilo Duque Velásquez, Judd Aiken & Debbie McKenzie
Veterinary Research volume 52, Article number: 115 (2021)
2023 CWD ZOONOSIS
PART 2. TPWD CHAPTER 65. DIVISION 1. CWD
31 TAC §§65.82, 65.85, 65.88
The Texas Parks and Wildlife Commission in a duly noticed meeting on May 25, 2023 adopted amendments to 31 TAC §§65.82, 65.85, and §65.88, concerning Disease Detection and Response, without changes to the proposed text as published in the April 21, 2023, issue of the Texas Register (48 TexReg 2048). The rules will not be republished.
Currently, there is scientific evidence to suggest that CWD has zoonotic potential; however, no confirmed cases of CWD have been found in humans.
17 DETECTION OF CHRONIC WASTING DISEASE PRIONS IN PROCESSED MEATS.
Rebeca Benavente1, Francisca Bravo1,2, Paulina Soto1,2, J. Hunter Reed3, Mitch Lockwood3, 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. 3Texas Parks and Wildlife, Austin, USA
Abstract
The zoonotic potential of chronic wasting disease (CWD) remains unknown. Currently, there are no known natural cases of CWD transmission to humans but increasing evidence suggests that the host range of CWD is not confined only to cervid species. Alarmingly, recent experimental evidence suggests that certain CWD isolates can induce disease in non-human primates. While the CDC strongly recommends determining CWD status in animals prior to consumption, this practice is voluntary. Consequently, it is plausible that a proportion of the cervid meat entering the human food chain may be contaminated with CWD. Of additional concern is that traditional diagnostic techniques used to detect CWD have relatively low sensitivity and are only approved for use in tissues other than those typically ingested by humans. In this study, we analyzed different processed meats derived from a pre-clinical, CWD-positive free-ranging elk. Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats. CWD-prion presence in these products were assessed by PMCA using deer and elk substrates. Our results show positive prion detection in all products. To confirm the resilience of CWD-prions to traditional cooking methods, we grilled and boiled the meat products and evaluated them for any remnant PMCA seeding activity. Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking. Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
***> Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats.
***> CWD-prion presence in these products were assessed by PMCA using deer and elk substrates.
***> Our results show positive prion detection in all products.
***> Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking.
***> Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
=====
9 Carrot plants as potential vectors for CWD transmission.
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
***> 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.
=====
Transmission of prion infectivity from CWD-infected macaque tissues to rodent models demonstrates the zoonotic potential of chronic wasting disease.
Samia Hannaoui1,2, Ginny Cheng1,2, Wiebke Wemheuer3, Walter Schulz-Schaeffer3, Sabine Gilch1,2, Hermann Schatzl1,2 1University of Calgary, Calgary, Canada. 2Calgary Prion Research Unit, Calgary, Canada. 3Institute of Neuropathology, Medical Faculty, Saarland University, Homburg/Saar, Germany
***> Further passage to cervidized mice revealed transmission with a 100% attack rate.
***> Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one.
****> The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Epidemiologic surveillance of prion disease among cervid hunters and people likely to have consumed venison contaminated with chronic wasting disease
=====
Chronic wasting disease (CWD) detection in environmental and biological samples from a taxidermy site
Paulina Soto1,2, J Hunter Reed3, Mitch Lockwood4, 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. 3Texas Parks and Wildlife Department, San Antonio, USA. 4Texas Parks and Wildlife Department, Kerrville, USA
Abstract
Chronic wasting disease (CWD) is a transmissible prionopathy affecting free-ranging and captive deer which can spread through both direct and indirect transmission. One area of concern is the risk of CWD transmission associated with taxidermy operations, especially since most CWD susceptible species brought to these operations are of unknown CWD status. Furthermore, taxidermy facilities can become a nidus of prion infectivity if biosecurity practices are not followed or implemented. In this study, we evaluated the presence of infectious prions in a taxidermy facility that was possibly exposed to CWD. To determine if the facility was exposed to CWD, we collected biological and environmental specimens from the facility, and we screened the samples for CWD prions through the protein misfolding cyclic amplification (PMCA) technique. Additionally, we swabbed different surfaces possibly exposed to CWD-infected animals or carcasses. For the PMCA reactions, we directly used a swab piece or 10 µL of 20% w/v homogenized samples. We detected the presence of prions in i) soils that were in contact with the heads of dead animals, ii) insects used to clean skulls, and iii) dumpsters where animal carcasses were disposed. This is the first report demonstrating that environmental swabbing is a useful surveillance method to screen for CWD-prion infectivity. In addition, our results suggest that CWD may be transmitted due to taxidermy practices.
''We detected the presence of prions in i) soils that were in contact with the heads of dead animals, ii) insects used to clean skulls, and iii) dumpsters where animal carcasses were disposed.''
=====end
Real-time quaking-induced conversion for prion detection in contaminated environmental samples
Stuart Lichtenberg1,2,3, Samuel Thomas3, Daniel Storm4, Daniel Walsh5
1University of Minnesota Department of Veterinary and Biomedical Sciences, St. Paul, USA. 2University of Minnesota Prion Research and Outreach Center, St. Paul, USA. 3University of Wisconsin-Madison Department of Soil Science, Madison, USA. 4Wisconsin Department of Natural Resources, Eau Claire, USA. 5U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, USA
Abstract
Chronic wasting disease (CWD) is unique among prion diseases in that it affects free-ranging host species. Consequently, indirect CWD transmission via prions shed by diseased animals into the broader environment is of great concern. Prions in the environment may contribute to further geographic spread of the disease, but adequate surveillance—a first step in management—is hampered by the lack of fit-for-purpose analytical methods. Antibody-based methods have limits of detection far above infection-relevant concentrations likely to be disbursed into the environment, and bioassays have experimental duration on the order of years. We describe here a method for extraction of prions from environmental matrices which are then amenable to detection by the real-time quaking induced conversion (RT-QuIC) assay. Furthermore, we characterize assay performance attributes (e.g., influence of organic matter) and demonstrate detection of prions from soil samples with varying properties.
=====end
Sensitive detection of swab-recovered chronic wasting disease prions from environmentally relevant surfaces
Qi Yuan1, Gage Rowden2, Tiffany Wolf2, Marc Schwabenlander2, Peter Larsen2, Shannon Bartelt-Hunt3, Jason Bartz1 1Creighton University, Omaha, USA. 2University of Minnesota, Saint Paul, USA. 3University of Nebraska-Lincoln, Omaha, USA
Abstract
Chronic wasting disease (CWD) has been identified in 30 states in the United States, four provinces in Canada, and recently in Scandinavia. Environmental elements such as soil, plants, and surfaces can harbor CWD prions for years and become persistent prion sources which exacerbate disease transmission. Therefore, it is critical to identify CWD prions in the environment to help monitor prion contamination and control disease transmission. An efficient method for CWD prion detection from contaminated environmental surfaces does not exist. In this study, we developed a rapid method for extracting prions from swabs using mechanical power and quantified prion recovery from different types of surfaces including glass, stainless steel, and wood. We found that drying of prions on swabs were unfavorable for extraction, requiring stronger mechanical power to achieve higher recovery. We found the recovery of surface-dried CWD prions were approximately 30% from glass and stainless steel, whereas wood-recovered CWD prions was below the detection limit of 96-well immunoassay. To detect surface-recovered prions beyond the detection limit of the immunoassay, we used real-time quaking-induced conversion (RT-QuIC), an ultrasensitive method, and found an increase of 4 orders of magnitude for CWD prions recovered from stainless steel. More importantly, the RT-QuIC seeding activity of stainless steel-recovered CWD prion was similar (< 1 Log) to that directly added to the RT-QuIC reaction. Our findings provided a rapid, ultrasensitive method for prion detection from contaminated surfaces which can be applied to monitor prion contamination in both environmental and medical settings.
=====end
Application of Methods for Detecting Environmental Prion Protein (ePrP) Via Surfaces to Managing Chronic Wasting Disease
Marc D Schwabenlander1,2, Catalina Picasso-Risso1,2, Sarah C. Gresch1,2, Marissa S. Milstein1,2, Gage Rowden1,2, Erik Hildebrand3, Patrick Hagen4, Mitch Lockwood5, Joseph Hediger6, Michael J. Cherry6, David G. Hewitt6, Qi Yuan7,2, Jason C. Bartz7,2, Tiffany M. Wolf8,2, Peter A. Larsen1,2
1Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA. 2Minnesota Center for Prion Research and Outreach, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA. 3Minnesota Department of Natural Resources, Forest Lake, MN, USA. 4Minnesota Department of Natural Resources.mn.us, Forest Lake, MN, USA. 5Texas Parks and Wildlife Department, Kerrville, TX, USA. 6Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX, USA. 7Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, USA. 8Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
Abstract
With increasing incidence and geographic spread of chronic wasting disease (CWD) across North America and Europe, developing highly sensitive misfolded prion (PrPSc) detection methodologies in order to combat CWD is urgently needed. Real-time quakinginduced conversion (RT-QuIC) is one such assay for PrPSc detection. Similar to environmental DNA (eDNA) advances for pathogen detection and species discovery in aquatic and terrestrial environments, our work investigates a rapid method for extracting and detecting prions from environmental surface swabs when paired with RT-QuIC. We applied our laboratory-based methods in three scenarios where environmental PrPSc detection can enhance early CWD detection - captive cervids, wild cervid targeted surveillance, and venison processing. We deployed surfaces known to bind PrPSc as environmental prion protein (ePrP) sentinels in food sources of herds with variable CWD prevalence. We detected PrPSc in natural settings using swabbing and extraction methods in conjunction with RT-QuIC. CWD prevalence of a captive deer herd correlated with intensity of PrPSc detection. For instance, 1 of 16 swabs were RTQuIC positive in a pen with 1 of 12 immunohistochemistry (IHC) positive animals. Further, in another pen with 13 of 19 IHC positive animals, 19 of 34 swabs were RT-QuIC positive. Importantly, we identified potential environmental factors (e.g., feed type) that affected RT-QuIC results. Initial results of venison processing surfaces indicated PrPSc can be detected after processing CWD-positive deer muscle. Furthermore, 10% bleach treatment eliminates detection. Our findings open the possibility for ePrP detection through noninvasive methods for early detection in CWD surveillance and management.
=====end
Chronic wasting disease prions in soils: fate and detection
Alsu Kuznetsova1, Erin Moffat2, Trent Bollinger2, Bjørnar Ytrehus3, Kjersti Selstad Utaaker3, Charlie Bahnson4, Debbie McKenzie5, Judd M. Aiken5
1University of Alberta, EDMONTON, Canada. 2University of Saskatchewan, Saskatoon, Canada. 3Norwegian Institute for Nature Research (NINA), Trondheim, Norway. 4North Dakota Game and Fish, Bismarck, USA. 5University of Alberta, Edmonton, Canada
Abstract
A remarkable property of CWD prions (PrPCWD) is their persistence in external environments and ability to remain infectious for years. Soils are a natural environmental reservoir of shed PrPCWD that increasing the risk for disease transmission, both within and between species. Environmental transmission of CWD via soil depends on soil properties: it is facilitated in the prairie regions, while lowered reduced bioavailability of environmental PrPCWD in boreal, tundra and alpine soils may reduce the efficiency of indirect transmission. Identification of CWD prions in soils would have numerous benefits, including monitoring spread and infectivity persistence. Prion detection in soils is challenging as recovery of soil-bound PrPCWD is influenced by soil texture, mineralogy, humus content and becomes more difficult with time.
We developed a reliable, sensitive method to detect PrPCWD in different type of soils with a level of detection, when soil bound, of 10−5-10−7 µg/µl. Soil surface horizon samples were collected from CWD-endemic regions with low and high CWD prevalence including prairie soils from North Dakota and southern Saskatchewan as well as boreal/alpine soils from Norway. Prions were extracted from soils and used as a seed for serial PMCA. PrPCWD were most commonly detected in soils from regions of high CWD prevalence (Saskatchewan) and not detected in prairie soils sampled from regions of low prevalence (North Dakota). PrPCWD were also amplified from soil samples of low CWD prevalence but where animals were concentrated near salt licks (Norway). This represents a significant improvement in soil-bound PrPCWD detection benefiting both surveillance and mitigation approaches.
=====end
Prion Forensics: a multidisciplinary approach to investigate chronic wasting disease at a deer carcass disposal site
Marc D. Schwabenlander1,2, Jason C. Bartz3, Michelle Carstensen4, Alberto Fameli5, Linda Glaser6, Roxanne J. Larsen1,2, Manci Li1,2, Laramie L. Lindsey1,2, Jonathan D. Oliver7, Rachel L. Shoemaker1,2, Gage Rowden1,2, Suzanne Stone1,2, W. David Walter8, Tiffany M. Wolf9,2, Peter A. Larsen1,2
1Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA. 2Minnesota Center for Prion Research and Outreach, College of Veterinary Medicine, University of Minnesota, St. Paul, USA. 3Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, USA. 4Minnesota Department of Natural Resources; Wildlife Health Program, Forest Lake, USA. 5Pennsylvania Cooperative Fish & Wildlife Research Unit, The Pennsylvania State University, University Park, USA. 6Minnesota Board of Animal Health, St. Paul, USA. 7Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, USA. 8U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, USA. 9Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, USA
Abstract
Chronic wasting disease (CWD) is confirmed in 30 US states, three Canadian provinces, Nordic countries, and South Korea. Although the origin and progression are typically unknown, CWD spread over the past seven decades is attributed, in part, to cervid carcass transport and disposal. Given the potential for CWD-causing prions to resist degradation and remain infectious within the environment, the disposal of CWD-positive animal remains, whether from free-ranging or captive sources, can play an important role in the transmission of CWD. Management agencies provide disposal guidance and opportunities to reduce the risk of introduction to new areas. Upon the discovery of an illegal carcass disposal site associated with a CWD-positive captive cervid facility, we leveraged an integrative multidisciplinary approach of anatomic, entomologic, genetic, and prion amplification methods to discover multiple CWDpositive remains of white-tailed deer across several age classes and, using microsatellite markers, we confirmed a portion of these remains originated from the CWD infected captive herd. CWD prions were detected via RT-QuIC in 14 of 56 carcass samples, including fly larvae associated with the remains. Our multi-methods approach, coined as “Prion Forensics”, provides the foundation for future investigations of prion transmission risk from carcass disposal.
''CWD prions were detected via RT-QuIC in 14 of 56 carcass samples, including fly larvae associated with the remains.''
=====end
Can We Leverage Environmental Contamination for CWD Surveillance?
Miranda Huang1, Steve Demarais1, Alejandro Banda2, Bronson Strickland1, Anna Grace Welch2, Scoty Hearst3, Stuart Lichtenberg4,5, Allan Houson6, Kim Pepin7, Kurt VerCauteren7
1Mississippi State University, Starkville, USA. 2Mississippi State University, Pearl, USA. 3Mississippi College, Clinton, USA. 4University of Minnesota, St. Paul, USA. 5University of Wisconsin-Madison, Madison, USA. 6University of Tennessee, Knoxville, USA. 7National Wildlife Research Center, Fort Collins, USA
Abstract
Chronic wasting disease (CWD) has impacted deer populations and upended wildlife management as it spreads across North America. One potential contributor to CWD environmental contamination is scraping behavior by white-tailed deer (Odocoileus virginianus, hereafter: WTD). Scraping communicates sociosexual status through disseminated bodily fluids (urine, saliva, glandular secretions) with the potential to spread infectious materials. We used data from 105 camera traps at scrapes over 4 months to document WTD visitation rates in southwestern Tennessee, an area with high CWD prevalence (~50%). We enhanced this analysis by testing prion levels in the soil of, and on the licking branch above, each scrape. Across 48 km2, we captured 3,063 scrape interactions by does, fawns, and 218 unique bucks. Scrapes were visited by an average of 12 unique bucks (standard deviation = 8, range = 1-39). We detected prion seeding activity in the soil of 20% and on the licking branches of 41% of Tennessee scrapes. We also collected soil and branch samples from scrapes in northern Mississippi, where CWD prevalence is lower (~8%). We detected prion seeding activity in the soil of 25% and on the licking branches of 11% of Mississippi scrapes. This environmental contamination at sites of natural deer congregation demonstrates the potential for prion exposure. Further, these results suggest scrapes could serve as environmental sentinels to identify CWD presence in an area without having to rely on testing harvested WTD. The potential for employing scrapes in the surveillance and management of CWD will be discussed.
"This environmental contamination at sites of natural deer congregation demonstrates the potential for prion exposure. Further, these results suggest scrapes could serve as environmental sentinels to identify CWD presence in an area without having to rely on testing harvested WTD."
=====end
16 Detection of CWD prion in feces of naturally infected, pre-clinical, farmed North America white-tailed deer
Francisca Bravo-Risi1,2, Paulina Soto1,2, Rebeca Benavente1, Tracy A. Nichols3, Rodrigo Morales1,4
1Department of Neurology, The University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Doctorado en Ciencias con Mención en Materiales Funcionales, Santiago, Chile. 3Veterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, USA. 4Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease (CWD) is a prion disease affecting cervids. Confirmatory testing of CWD is performed postmortem in obex and head lymphoid tissues. Our group has explored CWD-prion detection in various sample types using the protein misfolding cyclic amplification (PMCA) technique including antemortem samples such as blood and semen. Previous studies demonstrate the presence of infectious prions in feces of CWD-infected deer using in vitro prion-amplification techniques and bioassays. In experimental conditions, this has been achieved as soon as 6-month post-inoculation in cervids, suggesting feces may be a candidate for antemortem testing. We optimized the detection of CWD-prions in fecal samples from naturally infected, pre-clinical white-tailed deer (WTD) by comparing enrichment of CWD-prions by NaPTA, ultracentrifugation, and direct spiking of the sample to the PMCA reactions demonstrating that CWD-prion detection in feces is best in the absence of sample pre-treatments. The PMCA screening results of 169 fecal samples were compared with those previously published on blood. The detection of CWD-prions by PMCA in a late pre-clinical stage was similar for both sample types: 84% for feces and 87% for blood. These results contrasted with a lower detection observed at early pre-clinical stages (28% and 47% for feces and blood, respectively). Importantly, our analysis also considered the genetic variability at position 96 of the prion protein and sex. Overall, our findings contribute to understand prion distribution across different biological samples and polymorphic variants of WTD. This information is relevant for the current effort to identify platforms to diagnose CWD.
=====end
14 Protein misfolding cyclic amplification (PMCA) as an ultra-sensitive technique for the screening of CWD prions in different sample types.
Francisca Bravo-Risi1,2, Paulina Soto1,2, Rebeca Benavente1, Hunter Reed3, Mitch Lockwood3, Tracy A. Nichols4, Rodrigo Morales1,5 1Department of Neurology, The University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Doctorado en Ciencias con Mención en Materiales Funcionales, Santiago, Chile. 3Texas Park and Wildlife Department, Austin, USA. 4Veterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, USA. 5Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease (CWD) is a prion disease that affects farmed and free-ranging cervids. Currently, CWD status is ultimately confirmed in the brain and lymphoid tissues by immunohistochemistry (IHC). One limitation of IHC is its relatively poor sensitivity making it difficult to detect this disease early in the incubation period which can extend 1-3 years. Protein misfolding cyclic amplification (PMCA) and real-time quaking-induced conversion (RT-QuIC) are ultra-sensitive techniques that provide a means to detect CWD in early stages of the disease. PMCA mimics the self-propagation of infectious prions in vitro through multiple incubation-sonication cycles, increasing the number of prion particles present in a given sample. The detection of proteinase K (PK)-resistant PrPSc by PMCA has been performed in experimental and natural samples that may otherwise go undetected using traditional diagnostic techniques.
In this study, we highlight recent advances and contributions that our group has made detecting CWD-prions in animal and environmental samples collected from deer breeding and taxidermy facilities. Additionally, CWD-prions were detected in samples from hunter-harvested, free-ranging animals.
PMCA successfully detected CWD-prions in a diverse array of samples including blood, semen, feces, obex, retropharyngeal lymph node, fetuses (neural and peripheral tissues) and gestational tissues, parasites-insects, plants, compost-soil mixtures, and swabs from trash containers.
Importantly, our findings identified CWD in areas previously considered to be free of CWD. Overall, our findings demonstrate that PMCA is a powerful technique for the screening of biological and environmental samples, and it may prove useful as a CWD management and surveillance tool.
https://intcwdsympo.files.wordpress.com/2023/06/final-agenda-with-abstracts.pdf?force_download=true
Based on the North American experience, it seems reasonable to assume that live animals infected with CWD may be contagious to other cervid species, creating the potential for cross-species infection in susceptible animals. Moreover, in general, ‘on field’ carcasses of animals affected by any form of CWD (either Ly+ or Ly-) could be a potential source of exposure and/or give rise to environmental contamination (EFSA BIOHAZ Panel, 2019). Therefore, all cervid species in an area need to be taken into account when defining populations or geographic areas of reference.
Shedding of Chronic Wasting Disease Prions in Multiple Excreta Throughout Disease Course in White-tailed Deer
Nathaniel D. Denkersa, Erin E. McNultya, Caitlyn N. Krafta, Amy V. Nallsa, Joseph A. Westricha, Wilfred Goldmannb, Candace K. Mathiasona, and Edward A. Hoovera
aPrion Research Center, College of Veterinary Medicine and Biological Sciences, Department of Microbiology, Immunology, and Pathology; Colorado State University, Fort Collins, CO, USA; bDivision of Infection and Immunity, The Roslin Institute and the Royal Dick School of Veterinary Studies, University of Edinburgh, Midlothian, UK
Aims: Chronic wasting disease (CWD) now infects cervids in South Korea, North America, and Scandinavia. CWD is unique in its efficient transmission and shedding of prions in body fluids throughout long course infections. Questions remain as to the magnitude of shedding and the route of prion acquisition. As CWD continues to expand, the need to better understand these facets of disease becomes more pertinent. The purpose of the studies described was to define the longitudinal shedding profile of CWD prions in urine, saliva, and feces throughout the course of infection in white-tailed deer.
Material and Methods: Twelve (12) white-tailed deer were inoculated with either 1 mg or 300ng of CWD. Urine, saliva, and feces were collected every 3-month post-inoculation (MPI) throughout the study duration. Cohorts were established based on PNRP genotype: codon 96 GG (n = 6) and alternate codons 96 GS (n = 5) & 103NT (n = 1). Urine and saliva were analyzed using iron-oxide magnetic extraction (IOME) and real-time quaking induced conversion (RT-QuIC)(IQ). Feces were subjected to IOME, followed by 4 rounds protein misfolding cyclic amplification (PMCA) with products analyzed by RT-QuIC (IPQ). To determine whether IPQ may be superior to IQ, a subset of urine and saliva were also tested by IPQ. Results were compared with clinical disease status.
Results: Within the 96 GG cohort, positive seeding activity was detected in feces from all deer (100%), in saliva from 5 of 6 (83%), and in urine from 4 of 6 (66%). Shedding in all excreta occurred at, or just after, the first positive tonsil biopsy result. In the 96 GS/103NT cohort, positive seeding activity could be detected in feces from 3 of 6 (50%) deer, saliva in 2 of 6 (33%), and urine in 1 of 6 (16%). Shedding in excreta was detected >5 months after the first tonsil positive result. Four of six 96 GG deer developed clinical signs of CWD, whereas only 2 of the 96 GS/103NT did. Shedding was more frequently detected in deer with clinical disease. The IPQ protocol did not significantly improve detection in saliva or urine samples, however, it significantly augmented detection in feces by eliminating non-specific background commonly experienced with IQ. Negative control samples remained negative in samples tested.
Conclusions: These studies demonstrate: (a) CWD prion excretion occurs throughout infection; (2) PRNP genotype (GG≫GS/NT) influences the excreta shedding; and (3) detection sensitivity in excreta can vary with different RT-QuIC protocols. These results provide a more complete perspective of prion shedding in deer during the course of CWD infection.
Funded by: National Institutes of Health (NIH)
Grant number: RO1-NS061902-09 R to EAH, PO1-AI077774 to EAH, and R01-AI112956-06 to CKM
Acknowledgement: We abundantly thank Sallie Dahmes at WASCO and David Osborn and Gino D’Angelo at the University of Georgia Warnell School of Forestry and Natural Resources for their long-standing support of this work through provision of the hand-raised, CWD-free, white-tailed deer used in these studies
Carrot plants as potential vectors for CWD transmission
Paulina Sotoa,b, Francisca Bravo-Risia,b, Claudio Sotoa, and Rodrigo Moralesa,b
aDepartment of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; bUniversidad Bernardo O’Higgins, Santiago, Chile
Prion diseases are infectious neurodegenerative disorders afflicting humans and other mammals. These diseases are generated by the misfolding of the cellular prion protein into a disease-causing isoform. Chronic wasting disease (CWD) is a prevalent prion disease affecting cervids (captive and free-range). CWD is thought to be transmitted through direct animal contact or 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 do not fully understand the specific contribution of each component 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 animal and human nutrition.
Aims: The main objective of this study is to study whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait.
Methods: We have grown carrot plants in CWD-infected soils. After 90 days, we harvested the carrots and separated them from the leaves. The experiment was controlled by growing plants in soil samples treated with brain extracts from healthy animals. These materials were interrogated for their prion seeding activity using the Protein Misfolding Cyclic Amplification (PMCA) technique. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The animals were sacrificed when they showed established signs of prion disease. Animals not displaying clinical signs were sacrificed at 600 days post-inoculation.
Results: The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions, as well as in carrot plants (leaves and roots) grown on them. Bioassays demonstrated that both leaves and roots contained CWD prions in sufficient quantities to induce disease (92% attack rate). As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. Animals treated with soil and plant components exposed with CWD-free brain extracts did not display prion-associated clinical signs or evidence of sub-clinical prion infection.
Conclusions: We show that edible plant components can absorb prions from CWD contaminated soils and transport them to their aerial parts. Our results indicate that plants could participate as vectors of CWD transmission. Importantly, plants designated for human consumption represent a risk of introducing CWD prions into the human food chain.
Funded by: NIH
Grant number: R01AI132695
Carrots, TOMATOES, Plants, Straw, Hay, and CWD, what if?
Carrot plants as potential vectors for CWD transmission
Paulina Sotoa,b, Francisca Bravo-Risia,b, Claudio Sotoa, and Rodrigo Moralesa,b
aDepartment of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; bUniversidad Bernardo O’Higgins, Santiago, Chile
Prion diseases are infectious neurodegenerative disorders afflicting humans and other mammals. These diseases are generated by the misfolding of the cellular prion protein into a disease-causing isoform. Chronic wasting disease (CWD) is a prevalent prion disease affecting cervids (captive and free-range). CWD is thought to be transmitted through direct animal contact or 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 do not fully understand the specific contribution of each component 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 animal and human nutrition.
Aims: The main objective of this study is to study whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait.
Methods: We have grown carrot plants in CWD-infected soils. After 90 days, we harvested the carrots and separated them from the leaves. The experiment was controlled by growing plants in soil samples treated with brain extracts from healthy animals. These materials were interrogated for their prion seeding activity using the Protein Misfolding Cyclic Amplification (PMCA) technique. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The animals were sacrificed when they showed established signs of prion disease. Animals not displaying clinical signs were sacrificed at 600 days post-inoculation.
Results: The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions, as well as in carrot plants (leaves and roots) grown on them. Bioassays demonstrated that both leaves and roots contained CWD prions in sufficient quantities to induce disease (92% attack rate). As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. Animals treated with soil and plant components exposed with CWD-free brain extracts did not display prion-associated clinical signs or evidence of sub-clinical prion infection.
Conclusions: We show that edible plant components can absorb prions from CWD contaminated soils and transport them to their aerial parts. Our results indicate that plants could participate as vectors of CWD transmission. Importantly, plants designated for human consumption represent a risk of introducing CWD prions into the human food chain.
Funded by: NIH
Grant number: R01AI132695
P.157: Uptake of prions into plants
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
DISCUSSION
This study shows that plants can efficiently bind prions contained in brain extracts from diverse prion infected animals, including CWD-affected cervids. PrPSc attached to leaves and roots from wheat grass plants remains capable of seeding prion replication in vitro. Surprisingly, the small quantity of PrPSc naturally excreted in urine and feces from sick hamster or cervids was enough to efficiently contaminate plant tissue. Indeed, our results suggest that the majority of excreted PrPSc is efficiently captured by plants’ leaves and roots. Moreover, leaves can be contaminated by spraying them with a prion-containing extract, and PrPSc remains detectable in living plants for as long as the study was performed (several weeks). Remarkably, prion contaminated plants transmit prion disease to animals upon ingestion, producing a 100% attack rate and incubation periods not substantially longer than direct oral administration of sick brain homogenates. Finally, an unexpected but exciting result was that plants were able to uptake prions from contaminated soil and transport them to aerial parts of the plant tissue. Although it may seem farfetched that plants can uptake proteins from the soil and transport it to the parts above the ground, there are already published reports of this phenomenon (McLaren et al., 1960; Jensen and McLaren, 1960; Paungfoo-Lonhienne et al., 2008). The high resistance of prions to degradation and their ability to efficiently cross biological barriers may play a role in this process. The mechanism by which plants bind, retain, uptake, and transport prions is unknown. We are currently studying the way in which prions interact with plants using purified, radioactively labeled PrPSc to determine specificity of the interaction, association constant, reversibility, saturation, movement, etc.
Epidemiological studies have shown numerous instances of scrapie or CWD recurrence upon reintroduction of animals on pastures previously exposed to prion-infected animals. Indeed, reappearance of scrapie has been documented following fallow periods of up to 16 years (Georgsson et al., 2006), and pastures were shown to retain infectious CWD prions for at least 2 years after exposure (Miller et al., 2004). It is likely that the environmentally mediated transmission of prion diseases depends upon the interaction of prions with diverse elements, including soil, water, environmental surfaces, various invertebrate animals, and plants. However, since plants are such an important component of the environment and also a major source of food for many animal species, including humans, our results may have far-reaching implications for animal and human health. Currently, the perception of the risk for animal-to-human prion transmission has been mostly limited to consumption or exposure to contaminated meat; our results indicate that plants might also be an important vector of transmission that needs to be considered in risk assessment.
snip...see full text here ;
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
Friday, September 27, 2013
Uptake of Prions into Plants
PRION UPDATE VIA VEGETABLE PLANTS FROM THE SOIL
56. Members considered that there is no evidence that crops grown on the land which received composted excreta from BSE-challenged animals pose a TSE risk to humans or animals. One member suggested that, as some of these animals are orally challenged with high doses of BSE-infected materials, and the distribution of infectivity in the digestive system is not completely understood, it might be premature to conclude that there is no infective agent in the manure.
Furthermore, an unpublished study had indicated low level absorption of PrP from soil by tomato plants although it should be noted that this study had not been repeated. Details of this work would be sent to the SEAC Secretary. Dr Matthews explained that most of the manure from animals challenged with high doses of BSE had already been composted and used for coppicing. Members agreed that the risks from disposal of residual manure from experimental animals would be much less than historic risks of on farm contamination from naturally infected animals at the height of the BSE epidemic. ...SNIP...END
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.”
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
Web site
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
CWD North America EU early report
Cwd hay straw
Cwd
Transmission of cervid prions to humanized mice demonstrates the zoonotic potential of CWD
Original Paper
Open access
Published: 22 August 2022
volume 144, pages767–784 (2022)
Acta Neuropathologica
Transmission of cervid prions to humanized mice demonstrates the zoonotic potential of CWD
Samia Hannaoui, Irina Zemlyankina, Sheng Chun Chang, Maria Immaculata Arifin, Vincent Béringue, Debbie McKenzie, Hermann M. Schatzl & Sabine Gilch
Abstract
Prions cause infectious and fatal neurodegenerative diseases in mammals. Chronic wasting disease (CWD), a prion disease of cervids, spreads efficiently among wild and farmed animals. Potential transmission to humans of CWD is a growing concern due to its increasing prevalence. Here, we provide evidence for a zoonotic potential of CWD prions, and its probable signature using mice expressing human prion protein (PrP) as an infection model. Inoculation of these mice with deer CWD isolates resulted in atypical clinical manifestation with prion seeding activity and efficient transmissible infectivity in the brain and, remarkably, in feces, but without classical neuropathological or Western blot appearances of prion diseases. Intriguingly, the protease-resistant PrP in the brain resembled that found in a familial human prion disease and was transmissible upon second passage. Our results suggest that CWD might infect humans, although the transmission barrier is likely higher compared to zoonotic transmission of cattle prions. Notably, our data suggest a different clinical presentation, prion signature, and tissue tropism, which causes challenges for detection by current diagnostic assays. Furthermore, the presence of infectious prions in feces is concerning because if this occurs in humans, it is a source for human-to-human transmission. These findings have strong implications for public health and CWD management.
snip...
In contrast, in cervids affected with CWD, infectivity has been found in the lymphatic system, salivary gland, intestinal tract, muscles, antler velvet, blood, urine, saliva, and feces [4], which have been demonstrated to be transmissible [57]. CWD prions are shed into the environment via bodily fluids and excreta. They bind to soil and are taken up by plants, making the environment infectious for decades to come [4, 48]. The persistence of CWD prions in the environment amplifies the already effective transmission within and between cervid species. Therefore, CWD is considered to be the most contagious prion disease with fast spreading and efficient horizontal transmission.
HIGHLIGHTS OF THIS STUDY
================================
Our results suggest that CWD might infect humans, although the transmission barrier is likely higher compared to zoonotic transmission of cattle prions. Notably, our data suggest a different clinical presentation, prion signature, and tissue tropism, which causes challenges for detection by current diagnostic assays. Furthermore, the presence of infectious prions in feces is concerning because if this occurs in humans, it is a source for human-to-human transmission. These findings have strong implications for public health and CWD management.
In this study, we evaluated the zoonotic potential of CWD using a transgenic mouse model overexpressing human M129-PrPC (tg650[12]). We inoculated tg650 mice intracerebrally with two deer CWD isolates, Wisc-1 and 116AG [22, 23, 27, 29]. We demonstrate that this transgenic line was susceptible to infection with CWD prions and displayed a distinct leading clinical sign, an atypical PrPSc signature and unusual fecal shedding of infectious prions. Importantly, these prions generated by the human PrP transgenic mice were transmissible upon passage. Our results are the first evidence of a zoonotic risk of CWD when using one of the most common CWD strains, Wisc-1/CWD1 for infection. We demonstrated in a human transgenic mouse model that the species barrier for transmission of CWD to humans is not absolute. The fact that its signature was not typical raises the questions whether CWD would manifest in humans as a subclinical infection, whether it would arise through direct or indirect transmission including an intermediate host, or a silent to uncovered human-to-human transmission, and whether current detection techniques will be suffcient to unveil its presence.
Our findings strongly suggest that CWD should be regarded as an actual public health risk. Here, we use humanized mice to show that CWD prions can cross the species barrier to humans, and remarkably, infectious prions can be excreted in feces.
Our results indicate that if CWD crosses the species-barrier to humans, it is unlikely to resemble the most common forms of human prion diseases with respect to clinical signs, tissue tropism and PrPSc signature. For instance, PrPSc in variable protease-sensitive prionopathy (VPSPr), a sporadic form of human prion disease, and in the genetic form Gerstmann-Sträussler-Scheinker syndrome (GSS) is defined by an atypical PK-resistant PrPSc fragment that is non-glycosylated and truncated at both C- and N-termini, with a molecular weight between 6 and 8 kDa [24, 44–46]. These biochemical features are unique and distinctive from PrPSc (PrP27-30) found in most other human or animal prion disease. The atypical PrPSc signature detected in brain homogenate of tg650 mice #321 (1st passage) and #3063 (2nd passage), and the 7–8 kDa fragment (Figs. 2, 4) are very similar to that of GSS, both in terms of migration profile and the N-terminal cleavage site.
CWD in humans might remain subclinical but with PrPSc deposits in the brain with an unusual morphology that does not resemble the patterns usually seen in different prion diseases (e.g., mouse #328; Fig. 3), clinical with untraceable abnormal PrP (e.g., mouse #327) but still transmissible and uncovered upon subsequent passage (e.g., mouse #3063; Fig. 4), or prions have other reservoirs than the usual ones, hence the presence of infectivity in feces (e.g., mouse #327) suggesting a potential for human-to-human transmission and a real iatrogenic risk that might be unrecognizable.
suggesting a potential for human-to-human transmission and a real iatrogenic risk that might be unrecognizable.
=================================
Supplementary Information The online version contains supplementary material available at
snip...see full text;
Terry S. Singeltary Sr., Bacliff, Texas USA 77518, flounder9@verizon.net
posted by Terry S. Singeltary Sr. at
2:45 PM
0 Comments:
Post a Comment
Subscribe to Post Comments [Atom]
<< Home