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Booth CJ, Lichtenberg SS, Chappell RJ, Pedersen JA. Chemical Inactivation of Prions Is Altered by Binding to the Soil Mineral Montmorillonite. ACS Infect Dis 2021; 7:859-870. [PMID: 33787209 DOI: 10.1021/acsinfecdis.0c00860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Environmental routes of transmission contribute to the spread of the prion diseases chronic wasting disease of deer and elk and scrapie of sheep and goats. Prions can persist in soils and other environmental matrices and remain infectious for years. Prions bind avidly to the common soil mineral montmorillonite, and such binding can dramatically increase oral disease transmission. Decontamination of soil in captive facilities and natural habitats requires inactivation agents that are effective when prions are bound to soil microparticles. Here, we investigate the inactivation of free and montmorillonite-bound prions with sodium hydroxide, acidic pH, Environ LpH, and sodium hypochlorite. Immunoblotting and bioassays confirm that sodium hydroxide and sodium hypochlorite are effective for prion deactivation, although montmorillonite appears to reduce the efficacy of hypochlorite. Acidic conditions slightly reduce prion infectivity, and the acidic phenolic disinfectant Environ LpH produces slight reductions in infectivity and immunoreactivity. The extent to which the association with montmorillonite protects prions from chemical inactivation appears influenced by the effect of chemical agents on the clay structure and surface pH. When clay morphology remains relatively unaltered, as when exposed to hypochlorite, montmorillonite-bound prions appear to be protected from inactivation. In contrast, when the clay structure is substantially transformed, as when exposed to high concentrations of sodium hydroxide, the attachment to montmorillonite does not slow degradation. A reduction in surface pH appears to cause slight disruptions in clay structure, which enhances degradation under these conditions. We expect our findings will aid the development of remediation approaches for successful decontamination of prion-contaminated sites.
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Affiliation(s)
- Clarissa J. Booth
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin 53706, United States
| | | | - Richard J. Chappell
- Department of Biostatistics & Medical Informatics and Department of Statistics, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Joel A. Pedersen
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin 53706, United States
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin 53706, United States
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Somerville RA, Fernie K, Smith A, Bishop K, Maddison BC, Gough KC, Hunter N. BSE infectivity survives burial for five years with only limited spread. Arch Virol 2019; 164:1135-1145. [PMID: 30799509 PMCID: PMC6420460 DOI: 10.1007/s00705-019-04154-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/21/2018] [Indexed: 11/22/2022]
Abstract
The carcasses of animals infected with bovine spongiform encephalopathy (BSE), scrapie or chronic wasting disease (CWD) that remain in the environment (exposed or buried) may continue to act as reservoirs of infectivity. We conducted two experiments under near-field conditions to investigate the survival and dissemination of BSE infectivity after burial in a clay or sandy soil. BSE infectivity was either contained within a bovine skull or buried as an uncontained bolus of BSE-infected brain. Throughout the five-year period of the experiment, BSE infectivity was recovered in similar amounts from heads exhumed annually from both types of soil. Very low levels of infectivity were detected in the soil immediately surrounding the heads, but not in samples remote from them. Similarly, there was no evidence of significant lateral movement of infectivity from the buried bolus over 4 years although there was a little vertical movement in both directions. However, bioassay analysis of limited numbers of samples of rain water that had drained through the bolus clay lysimeter indicated that infectivity was present in filtrates. sPMCA analysis also detected low levels of PrPSc in the filtrates up to 25 months following burial, raising the concern that leakage of infectivity into ground water could occur. We conclude that transmissible spongiform encephalopathy infectivity is likely to survive burial for long periods of time, but not to migrate far from the site of burial unless a vector or rain water drainage transports it. Risk assessments of contaminated sites should take these findings into account.
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Affiliation(s)
- Robert A Somerville
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Karen Fernie
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Allister Smith
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Keith Bishop
- ADAS Biotechnology, School of Veterinary Medicine and Science, The University of Nottingham, College Rd., Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Ben C Maddison
- ADAS Biotechnology, School of Veterinary Medicine and Science, The University of Nottingham, College Rd., Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Kevin C Gough
- School of Veterinary Medicine and Science, The University of Nottingham, College Rd., Sutton Bonington, Leicestershire, LE12 5RD, UK.
| | - Nora Hunter
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.
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Plummer IH, Johnson CJ, Chesney AR, Pedersen JA, Samuel MD. Mineral licks as environmental reservoirs of chronic wasting disease prions. PLoS One 2018; 13:e0196745. [PMID: 29719000 PMCID: PMC5931637 DOI: 10.1371/journal.pone.0196745] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Chronic wasting disease (CWD) is a fatal neurodegenerative disease of deer, elk, moose, and reindeer (cervids) caused by misfolded prion proteins. The disease has been reported across North America and recently discovered in northern Europe. Transmission of CWD in wild cervid populations can occur through environmental routes, but limited ability to detect prions in environmental samples has prevented the identification of potential transmission "hot spots". We establish widespread CWD prion contamination of mineral licks used by free-ranging cervids in an enzootic area in Wisconsin, USA. We show mineral licks can serve as reservoirs of CWD prions and thus facilitate disease transmission. Furthermore, mineral licks attract livestock and other wildlife that also obtain mineral nutrients via soil and water consumption. Exposure to CWD prions at mineral licks provides potential for cross-species transmission to wildlife, domestic animals, and humans. Managing deer use of mineral licks warrants further consideration to help control outbreaks of CWD.
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Affiliation(s)
- Ian H. Plummer
- Department of Forest & Wildlife Ecology, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Chad J. Johnson
- Departments of Soil Science, Chemistry, and Civil & Environmental Engineering, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Alexandra R. Chesney
- Molecular and Environmental Toxicology Center, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Joel A. Pedersen
- Departments of Soil Science, Chemistry, and Civil & Environmental Engineering, Molecular and Environmental Toxicology Center, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- * E-mail: (MDS); (JAP)
| | - Michael D. Samuel
- Department of Forest & Wildlife Ecology, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- * E-mail: (MDS); (JAP)
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Mejía‐Salazar MF, Waldner CL, Hwang YT, Bollinger TK. Use of environmental sites by mule deer: a proxy for relative risk of chronic wasting disease exposure and transmission. Ecosphere 2018. [DOI: 10.1002/ecs2.2055] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- María Fernanda Mejía‐Salazar
- Department of Veterinary Pathology University of Saskatchewan 52 Campus Drive Saskatoon Saskatchewan S7N 5B4 Canada
| | - Cheryl L. Waldner
- Department of Large Animal Clinical Sciences University of Saskatchewan 52 Campus Drive Saskatoon Saskatchewan S7N 5B4 Canada
| | - Yeen Ten Hwang
- Department of Veterinary Pathology University of Saskatchewan 52 Campus Drive Saskatoon Saskatchewan S7N 5B4 Canada
- Fish and Wildlife Branch Saskatchewan Ministry of Environment Regina Saskatchewan S4S 5W6 Canada
| | - Trent K. Bollinger
- Department of Veterinary Pathology University of Saskatchewan 52 Campus Drive Saskatoon Saskatchewan S7N 5B4 Canada
- Canadian Wildlife Health Cooperative (CWHC) 52 Campus Drive Saskatoon Saskatchewan S7N 5B4 Canada
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Dorak SJ, Green ML, Wander MM, Ruiz MO, Buhnerkempe MG, Tian T, Novakofski JE, Mateus-Pinilla NE. Clay content and pH: soil characteristic associations with the persistent presence of chronic wasting disease in northern Illinois. Sci Rep 2017; 7:18062. [PMID: 29273783 PMCID: PMC5741720 DOI: 10.1038/s41598-017-18321-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/08/2017] [Indexed: 01/13/2023] Open
Abstract
Environmental reservoirs are important to infectious disease transmission and persistence, but empirical analyses are relatively few. The natural environment is a reservoir for prions that cause chronic wasting disease (CWD) and influences the risk of transmission to susceptible cervids. Soil is one environmental component demonstrated to affect prion infectivity and persistence. Here we provide the first landscape predictive model for CWD based solely on soil characteristics. We built a boosted regression tree model to predict the probability of the persistent presence of CWD in a region of northern Illinois using CWD surveillance in deer and soils data. We evaluated the outcome for possible pathways by which soil characteristics may increase the probability of CWD transmission via environmental contamination. Soil clay content and pH were the most important predictive soil characteristics of the persistent presence of CWD. The results suggest that exposure to prions in the environment is greater where percent clay is less than 18% and soil pH is greater than 6.6. These characteristics could alter availability of prions immobilized in soil and contribute to the environmental risk factors involved in the epidemiological complexity of CWD infection in natural populations of white-tailed deer.
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Affiliation(s)
- Sheena J Dorak
- Illinois Natural History Survey - Prairie Research Institute, University of Illinois Urbana-Champaign, 1816 S Oak Street, Champaign, IL, 61820, USA
| | - Michelle L Green
- Illinois Natural History Survey - Prairie Research Institute, University of Illinois Urbana-Champaign, 1816 S Oak Street, Champaign, IL, 61820, USA.,Department of Animal Sciences, University of Illinois Urbana-Champaign, 1503 S Maryland Drive, Urbana, IL, 61801, USA
| | - Michelle M Wander
- Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, 1102 S Goodwin Ave, Urbana, IL, 61801, USA
| | - Marilyn O Ruiz
- Department of Pathobiology, University of Illinois Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL, 61802, USA
| | - Michael G Buhnerkempe
- Illinois Natural History Survey - Prairie Research Institute, University of Illinois Urbana-Champaign, 1816 S Oak Street, Champaign, IL, 61820, USA
| | - Ting Tian
- Illinois Natural History Survey - Prairie Research Institute, University of Illinois Urbana-Champaign, 1816 S Oak Street, Champaign, IL, 61820, USA
| | - Jan E Novakofski
- Department of Animal Sciences, University of Illinois Urbana-Champaign, 1503 S Maryland Drive, Urbana, IL, 61801, USA
| | - Nohra E Mateus-Pinilla
- Illinois Natural History Survey - Prairie Research Institute, University of Illinois Urbana-Champaign, 1816 S Oak Street, Champaign, IL, 61820, USA.
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Chesney AR, Booth CJ, Lietz CB, Li L, Pedersen JA. Peroxymonosulfate Rapidly Inactivates the Disease-Associated Prion Protein. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:7095-105. [PMID: 27247993 PMCID: PMC5337124 DOI: 10.1021/acs.est.5b06294] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Prions, the etiological agents in transmissible spongiform encephalopathies, exhibit remarkable resistance to most methods of inactivation that are effective against conventional pathogens. Prions are composed of pathogenic conformers of the prion protein (PrP(TSE)). Some prion diseases are transmitted, in part, through environmental routes. The recalcitrance of prions to inactivation may lead to a persistent reservoir of infectivity that contributes to the environmental maintenance of epizootics. At present, few methods exist to remediate prion-contaminated land surfaces. Here we conducted a proof-of-principle study to examine the ability of peroxymonosulfate to degrade PrP(TSE). We find that peroxymonosulfate rapidly degrades PrP(TSE) from two species. Transition-metal-catalyzed decomposition of peroxymonosulfate to produce sulfate radicals appears to enhance degradation. We further demonstrate that exposure to peroxymonosulfate significantly reduced PrP(C) to PrP(TSE) converting ability as measured by protein misfolding cyclic amplification, used as a proxy for infectivity. Liquid chromatography-tandem mass spectrometry revealed that exposure to peroxymonosulfate results in oxidative modifications to methionine and tryptophan residues. This study indicates that peroxymonosulfate may hold promise for decontamination of prion-contaminated surfaces.
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Affiliation(s)
- Alexandra R. Chesney
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Clarissa J. Booth
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
| | | | - Lingjun Li
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
- School of Pharmacy, University of Wisconsin, Madison, WI 53706, USA
| | - Joel A. Pedersen
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Soil Science, University of Wisconsin, Madison, WI 53706, USA
- Corresponding Author: tel: (608) 263-4971; fax: (608) 265-2595;
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Kuznetsova A, McKenzie D, Banser P, Siddique T, Aiken JM. Potential role of soil properties in the spread of CWD in western Canada. Prion 2015; 8:92-9. [PMID: 24618673 DOI: 10.4161/pri.28467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chronic wasting disease (CWD) is a horizontally transmissible prion disease of free ranging deer, elk and moose. Recent experimental transmission studies indicate caribou are also susceptible to the disease. CWD is present in southeast Alberta and southern Saskatchewan. This CWD-endemic region is expanding, threatening Manitoba and areas of northern Alberta and Saskatchewan, home to caribou. Soil can serve as a stable reservoir for infectious prion proteins; prions bound to soil particles remain infectious in the soils for many years. Soils of western Canada are very diverse and the ability of CWD prions to bind different soils and the impact of this interaction on infectivity is not known. In general, clay-rich soils may bind prions avidly and enhance their infectivity comparable to pure clay mineral montmorillonite. Organic components of soils are also diverse and not well characterized, yet can impact prion-soil interaction. Other important contributing factors include soil pH, composition of soil solution and amount of metals (metal oxides). In this review, properties of soils of the CWD-endemic region in western Canada with its surrounding terrestrial environment are described and used to predict bioavailability and, thus, potential spread of CWD. The major soils in the CWD-endemic region of Alberta and Saskatchewan are Chernozems, present in 60% of the total area; they are generally similar in texture, clay mineralogy and soil organic matter content, and can be characterized as clay loamy, montmorillonite (smectite) soils with 6-10% organic carbon. The greatest risk of CWD spread in western Canada relates to clay loamy, montmorillonite soils with humus horizon. Such soils are predominant in the southern region of Alberta, Saskatchewan and Manitoba, but are less common in northern regions of the provinces where quartz-illite sandy soils with low amount of humus prevail.
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Abstract
A naturally occurring transmissible spongiform encephalopathy (TSE) of mule deer was first reported in Colorado and Wyoming in 1967 and has since spread to other members of the cervid family in 22 states, 2 Canadian provinces, and the Republic of Korea. Chronic wasting disease (CWD), caused by exposure to an abnormally folded isoform of the cellular prion protein, is characterized by progressive neurological disease in susceptible natural and experimental hosts and is ultimately fatal. CWD is thought to be transmitted horizontally in excreta and through contaminated environments, features common to scrapie of sheep, though rare among TSEs. Evolving detection methods have revealed multiple strains of CWD and with continued development may lead to an effective antemortem test. Managing the spread of CWD, through the development of a vaccine or environmental cleanup strategies, is an active area of interest. As such, CWD represents a unique challenge in the study of prion diseases.
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Affiliation(s)
- Nicholas J Haley
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, Kansas 66506;
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Xu S, Reuter T, Gilroyed BH, Mitchell GB, Price LM, Dudas S, Braithwaite SL, Graham C, Czub S, Leonard JJ, Balachandran A, Neumann NF, Belosevic M, McAllister TA. Biodegradation of prions in compost. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:6909-6918. [PMID: 24819143 DOI: 10.1021/es500916v] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Composting may serve as a practical and economical means of disposing of specified risk materials (SRM) or animal mortalities potentially infected with prion diseases (transmissible spongiform encephalopathies, TSE). Our study investigated the degradation of prions associated with scrapie (PrP(263K)), chronic waste disease (PrP(CWD)), and bovine spongiform encephalopathy (PrP(BSE)) in lab-scale composters and PrP(263K) in field-scale compost piles. Western blotting (WB) indicated that PrP(263K), PrP(CWD), and PrP(BSE) were reduced by at least 2 log10, 1-2 log10, and 1 log10 after 28 days of lab-scale composting, respectively. Further analysis using protein misfolding cyclic amplification (PMCA) confirmed a reduction of 2 log10 in PrP(263K) and 3 log10 in PrP(CWD). Enrichment for proteolytic microorganisms through the addition of feather keratin to compost enhanced degradation of PrP(263K) and PrP(CWD). For field-scale composting, stainless steel beads coated with PrP(263K) were exposed to compost conditions and removed periodically for bioassays in Syrian hamsters. After 230 days of composting, only one in five hamsters succumbed to TSE disease, suggesting at least a 4.8 log10 reduction in PrP(263K) infectivity. Our findings show that composting reduces PrP(TSE), resulting in one 50% infectious dose (ID50) remaining in every 5600 kg of final compost for land application. With these considerations, composting may be a viable method for SRM disposal.
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Affiliation(s)
- Shanwei Xu
- Agriculture and Agri-Food Canada, Lethbridge Research Centre , Lethbridge, Alberta T1J 4B1, Canada
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10
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Wyckoff AC, Lockwood KL, Meyerett-Reid C, Michel BA, Bender H, VerCauteren KC, Zabel MD. Estimating prion adsorption capacity of soil by BioAssay of Subtracted Infectivity from Complex Solutions (BASICS). PLoS One 2013; 8:e58630. [PMID: 23484043 PMCID: PMC3587580 DOI: 10.1371/journal.pone.0058630] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Accepted: 02/05/2013] [Indexed: 11/25/2022] Open
Abstract
Prions, the infectious agent of scrapie, chronic wasting disease and other transmissible spongiform encephalopathies, are misfolded proteins that are highly stable and resistant to degradation. Prions are known to associate with clay and other soil components, enhancing their persistence and surprisingly, transmissibility. Currently, few detection and quantification methods exist for prions in soil, hindering an understanding of prion persistence and infectivity in the environment. Variability in apparent infectious titers of prions when bound to soil has complicated attempts to quantify the binding capacity of soil for prion infectivity. Here, we quantify the prion adsorption capacity of whole, sandy loam soil (SLS) typically found in CWD endemic areas in Colorado; and purified montmorillonite clay (Mte), previously shown to bind prions, by BioAssay of Subtracted Infectivity in Complex Solutions (BASICS). We incubated prion positive 10% brain homogenate from terminally sick mice infected with the Rocky Mountain Lab strain of mouse-adapted prions (RML) with 10% SLS or Mte. After 24 hours samples were centrifuged five minutes at 200×g and soil-free supernatant was intracerebrally inoculated into prion susceptible indicator mice. We used the number of days post inoculation to clinical disease to calculate the infectious titer remaining in the supernatant, which we subtracted from the starting titer to determine the infectious prion binding capacity of SLS and Mte. BASICS indicated SLS bound and removed ≥ 95% of infectivity. Mte bound and removed lethal doses (99.98%) of prions from inocula, effectively preventing disease in the mice. Our data reveal significant prion-binding capacity of soil and the utility of BASICS to estimate prion loads and investigate persistence and decomposition in the environment. Additionally, since Mte successfully rescued the mice from prion disease, Mte might be used for remediation and decontamination protocols.
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Affiliation(s)
- A. Christy Wyckoff
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
- National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
| | - Krista L. Lockwood
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
| | - Crystal Meyerett-Reid
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
| | - Brady A. Michel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
| | - Heather Bender
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
| | - Kurt C. VerCauteren
- National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
| | - Mark D. Zabel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, United States of America
- * E-mail:
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Xu S, Reuter T, Gilroyed BH, Dudas S, Graham C, Neumann NF, Balachandran A, Czub S, Belosevic M, Leonard JJ, McAllister TA. Biodegradation of specified risk material and fate of scrapie prions in compost. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2013; 48:26-36. [PMID: 23030385 DOI: 10.1080/10934529.2012.707599] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Composting may be a viable alternative to rendering and land filling for the disposal of specified risk material (SRM) provided that infectious prion proteins (PrP(TSE)) are inactivated. This study investigated the degradation of SRM and the fate of scrapie prions (PrP(Sc)) over 28 days in laboratory-scale composters, with and without feathers in the compost matrices. Compost was mixed at day 14 to generate a second heating cycle, with temperatures exceeding 65°C in the first cycle and 50°C in the second cycle. Approximately 63% and 77% of SRM was degraded after the first and second cycles, respectively. Inclusion of feathers in the compost matrices did not alter compost properties during composting other than increasing (P < 0.05) total nitrogen and reducing (P < 0.05) the C/N ratio. However, addition of feathers enhanced (P < 0.05) SRM degradation by 10% upon completion of experiment. Scrapie brain homogenates were spiked into manure at the start of composting and extracted using sodium dodecyl sulphate followed by detection using Western blotting (WB). Prior to composting, PrP(Sc) was detectable in manure with 1-2 log(10) sensitivity, but was not observable after 14 or 28 days of composting. This may have been due to either biological degradation of PrP(Sc) or the formation of complexes with compost components that precluded its detection.
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Affiliation(s)
- Shanwei Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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12
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Saunders SE, Bartz JC, Bartelt-Hunt SL. Soil-mediated prion transmission: is local soil-type a key determinant of prion disease incidence? CHEMOSPHERE 2012; 87:661-667. [PMID: 22265680 DOI: 10.1016/j.chemosphere.2011.12.076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 12/23/2011] [Accepted: 12/28/2011] [Indexed: 05/31/2023]
Abstract
Prion diseases, including chronic wasting disease (CWD) and scrapie, can be transmitted via indirect environmental routes. Animals habitually ingest soil, and results from laboratory experiments demonstrate prions can bind to a wide range of soils and soil minerals, retain the ability to replicate, and remain infectious, indicating soil could serve as a reservoir for natural prion transmission and a potential prion exposure route for humans. Preliminary epidemiological modeling suggests soil texture may influence the incidence of prion disease. These results are supported by experimental work demonstrating variance in prion interactions with soil, including variance in prion soil adsorption and soil-bound prion replication with respect to soil type. Thus, local soil type may be a key determinant of prion incidence. Further experimental and epidemiological work is required to fully elucidate the dynamics of soil-mediated prion transmission, an effort that should lead to effective disease management and mitigation strategies.
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Affiliation(s)
- Samuel E Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, NE 68182, USA
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Bastian FO, Elzer PH, Wu X. Spiroplasma spp. biofilm formation is instrumental for their role in the pathogenesis of plant, insect and animal diseases. Exp Mol Pathol 2012; 93:116-28. [PMID: 22552100 DOI: 10.1016/j.yexmp.2012.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 03/20/2012] [Accepted: 04/11/2012] [Indexed: 01/25/2023]
Abstract
Spiroplasma spp. are important phyto and insect pathogens, and candidate causal agent/s of transmissible spongiform encephalopathies (TSE) in man and animals. These filterable wall-less bacteria are widely distributed in nature with an unspecified environmental reservoir. In this study we showed by scanning electron microscopy that spiroplasma form biofilm on an assortment of hard surfaces including mica, nickel and stainless steel. Spiroplasma were stuck to the surfaces by fibrillar threads consistent with curli fibers (an amyloid protein found in bacterial biofilms). After a lengthy time in cultures (6 weeks), spiroplasma in biofilm bound to mica disks lost their spiral shapes and formed coccoid forms interconnected by long (>2 μm) branched membranous nanotubules, therein representing direct conjugate connections between the cells. The affinity of spiroplasma biofilms for mica and nickel, and the membrane communications suggest that soil could be a reservoir for these bacteria. The persistence of clay bound spiroplasma in soil could serve as the mechanism of lateral spread of TSEs by ingestion of soil by ruminants. Spiroplasma binding to stainless steel wire supports bacterial contamination of surgical instruments following surgery on dementia patients as a mechanism of iatrogenic transmission of TSEs, especially with resistance of spiroplasma in biofilms to drying or exposure to 50% glutaraldehyde. The discovery of biofilm formation by spiroplasma addresses questions regarding environmental persistence of these organisms in nature and suggests novel mechanisms of intercellular communication and transmission.
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Affiliation(s)
- Frank O Bastian
- Department of Veterinary Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
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Saunders SE, Yuan Q, Bartz JC, Bartelt-Hunt S. Effects of solution chemistry and aging time on prion protein adsorption and replication of soil-bound prions. PLoS One 2011; 6:e18752. [PMID: 21526178 PMCID: PMC3079715 DOI: 10.1371/journal.pone.0018752] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 03/17/2011] [Indexed: 11/18/2022] Open
Abstract
Prion interactions with soil may play an important role in the transmission of chronic wasting disease (CWD) and scrapie. Prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. We investigated HY TME prion protein (PrP(Sc)) adsorption to soil minerals in aqueous solutions of phosphate buffered saline (PBS), sodium chloride, calcium chloride, and deionized water using western blotting. The replication efficiency of bound prions following adsorption in these solutions was also evaluated by protein misfolding cyclic amplification (PMCA). Aging studies investigated PrP(Sc) desorption and replication efficiency up to one year following adsorption in PBS or DI water. Results indicate that adsorption solution chemistry can affect subsequent prion replication or desorption ability, especially after incubation periods of 30 d or longer. Observed effects were minor over the short-term (7 d or less). Results of long-term aging experiments demonstrate that unbound prions or prions bound to a diverse range of soil surfaces can readily replicate after one year. Our results suggest that while prion-soil interactions can vary with solution chemistry, prions bound to soil could remain a risk for transmitting prion diseases after months in the environment.
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Affiliation(s)
- Samuel E. Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, United States of America
| | - Qi Yuan
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, United States of America
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Shannon Bartelt-Hunt
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, United States of America
- * E-mail:
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15
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Smith CB, Booth CJ, Pedersen JA. Fate of prions in soil: a review. JOURNAL OF ENVIRONMENTAL QUALITY 2011; 40:449-461. [PMID: 21520752 PMCID: PMC3160281 DOI: 10.2134/jeq2010.0412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Prions are the etiological agents of transmissible spongiform encephalopathies (TSSEs), a class of fatal neurodegenerative diseases affecting humans and other mammals. The pathogenic prion protein is a misfolded form of the host-encoded prion protein and represents the predominant, if not sole, component of the infectious agent. Environmental routes of TSE transmission areimplicated in epizootics of sheep scrapie and chronic wasting disease (CWD) of deer, elk, and moose. Soil represents a plausible environmental reservoir of scrapie and CWD agents, which can persist in the environment for years. Attachment to soil particles likely influences the persistence and infectivity of prions in the environment. Effective methods to inactivate TSE agents in soil are currently lacking, and the effects of natural degradation mechanisms on TSE infectivity are largely unknown. An improved understanding of the processes affecting the mobility, persistence, and bioaviailability of prions in soil is needed for the management of TSE-contaminated environments.
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Affiliation(s)
- Christen B. Smith
- Environmental Chemistry and Technology Program, Univ. of Wisconsin, 1525 Observatory Dr., Madison, WI 53706
| | - Clarissa J. Booth
- Molecular and Environmental Toxicology Center, Univ. of Wisconsin, 1525 Observatory Dr., Madison, WI 53706
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16
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Zimmer N, Boxall PC, Adamowicz WLV. The impact of chronic wasting disease and its management on hunter perceptions, opinions, and behaviors in Alberta, Canada. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:1621-1635. [PMID: 22043918 DOI: 10.1080/15287394.2011.618988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The goal of this analysis was to identify changes in hunting behavior, satisfaction, and perceptions of risk in the presence of chronic wasting disease (CWD). Hunters completed an Internet survey containing direct questions regarding the impacts of CWD and gathering information about real and hypothetical hunting trips. Overall, hunters were satisfied with CWD management, and although certain behaviors were altered, the perceived risk by hunters did not seem to be high. A travel cost model was used to determine whether differences in trip frequencies might be observed in response to CWD. The largest variation in trips was between urban and rural hunters, with urban hunters being less averse to traveling but more averse to CWD and the management program of extra tags.
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Affiliation(s)
- Natalie Zimmer
- Department of Resource Economics and Environmental Sociology, University of Alberta, Edmonton, AB, Canada
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17
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Miles SL, Takizawa K, Gerba CP, Pepper IL. Survival of infectious prions in Class B biosolids. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:364-370. [PMID: 21391030 DOI: 10.1080/10934529.2011.542386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This study developed a method for extracting infectious prions from Class B biosolids and subsequently evaluated the survival of infectious prions under the influence of mesophilic (37°C) and thermophilic (60°C) temperatures in Class B biosolids. Unlike other studies, this study utilized a scrapie cell assay to determine infectivity and quantity of infectious prions. The best method for extraction was exposing the biosolids to 4 M urea at 80°C for 10 minutes followed by a membrane centrifugation to reduce the concentration of urea. The recovery efficiency of the infectious prions from the biosolids for this method was 17.2%. In the survival study, a 2.43-log(10) reduction in prion infectivity was observed under mesophilic temperatures after 15 days and a 3.41-log(10) reduction after 10 days under thermophilic conditions. The reduction of infectious prions was greater in the biosolids than the control in phosphate buffered saline, suggesting factors other than temperature were also playing a role in the loss of infectivity of the prions in the biosolids.
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Affiliation(s)
- Syreeta L Miles
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, Arizona, USA.
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18
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Maddison BC, Owen JP, Bishop K, Shaw G, Rees HC, Gough KC. The interaction of ruminant PrP(Sc) with soils is influenced by prion source and soil type. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:8503-8508. [PMID: 20968294 DOI: 10.1021/es101591a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The persistence of prions within the environment is implicated in the horizontal transmission of ovine scrapie and cervid chronic wasting disease. Description of the interaction of prion strains derived from their natural hosts with a range of soil types is imperative in understanding how prions persist in the environment and, therefore, the characteristics of prion transmission. Here, we demonstrate that all detectable ovine scrapie and bovine BSE PrP(Sc) bind to a range of soil types within 24 h. This highly efficient binding of prions to soils is characterized by truncation of desorbed PrP(Sc) in a soil-dependent manner, with clay-rich soils resulting in N-terminal truncation of the PrP(Sc) and sand-rich soils yielding full length PrP(Sc) species. PrP(Sc) did not migrate through soil columns during incubation for up to 18 months, and for all combinations of soil and prion types, a decrease in recoverable PrP(Sc) was seen over time. Persistence of PrP(Sc) within soil and their interaction with soil particles of distinct sizes was dictated by both the soil type and the source of the prion, with ovine scrapie being apparently more persistent in some soils than cattle BSE. These data indicate that natural ruminant prion strains are stable in the soil environment for at least 18 months and that PrP(Sc)-soil interaction is dictated by both the soil properties and the strain/host species of PrP(Sc).
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Affiliation(s)
- Ben C Maddison
- ADAS U.K., Department of Biology, University of Leicester, Leicester, LE1 7RH, UK
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19
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Jacobson KH, Lee S, Somerville RA, McKenzie D, Benson CH, Pedersen JA. Transport of the pathogenic prion protein through soils. JOURNAL OF ENVIRONMENTAL QUALITY 2010; 39:1145-52. [PMID: 20830901 PMCID: PMC3073504 DOI: 10.2134/jeq2009.0137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Transmissible spongiform encephalopathies (TSEs) are progressive neurodegenerative diseases and include bovine spongiform encephalopathy of cattle, chronic wasting disease (CWD) of deer and elk, scrapie in sheep and goats, and Creutzfeldt-Jakob disease in humans. An abnormally folded form of the prion protein (designated PrP(TSE)) is typically associated with TSE infectivity and may constitute the major, if not sole, component of the infectious agent. Transmission of CWD and scrapie is mediated in part by an environmental reservoir of infectivity. Soil appears to be a plausible candidate for this reservoir. The transport of TSE agent through soil is expected to influence the accessibility of the pathogen to animals after deposition and must be understood to assess the risks associated with burial of infected carcasses. We report the results of saturated column experiments designed to evaluate PrP(TSE) transport through five soils with relatively high sand or silt contents and low organic carbon content. Protease-treated TSE-infected brain homogenate was used as a model for PrP(TSE) present in decomposing infected tissue. Synthetic rainwater was used as the eluent. All five soils retained PrP(TSE); no detectable PrP(TSE) was eluted over more than 40 pore volumes of flow. Lower bound apparent attachment coefficients were estimated for each soil. Our results suggest that TSE agent released from decomposing tissues to soils with low organic carbon content would remain near the site of initial deposition. In the case of infected carcasses deposited on the land surface, this may result in local sources of infectivity to other animals.
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Affiliation(s)
- Kurt H. Jacobson
- Civil & Environmental Engineering, University of Wisconsin, Madison, WI 53706, USA
| | - Seunghak Lee
- Research and Development Planning Department, Technology & Innovation Development Office, Hyundai Engineering Company Ltd., Hyundai 41 Tower 917-9, Mok-dong, Yangcheon-gu, Seoul 158-723, Korea
| | - Robert A. Somerville
- Neuropathogenesis Division, The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh EH9 3JF, Scotland UK
| | - Debbie McKenzie
- Centre for Prions and Protein Folding Diseases, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
| | - Craig H. Benson
- Geological Engineering, University of Wisconsin, Madison, WI 53706, USA
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20
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Nagaoka K, Yoshioka M, Shimozaki N, Yamamura T, Murayama Y, Yokoyama T, Mohri S. Sensitive detection of scrapie prion protein in soil. Biochem Biophys Res Commun 2010; 397:626-30. [PMID: 20570651 DOI: 10.1016/j.bbrc.2010.06.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 06/02/2010] [Indexed: 10/19/2022]
Abstract
Prion diseases are fatal neurodegenerative disorders that are caused by infectious agents known as prions. Prions are composed primarily of the pathogenic prion protein isoform, PrP(Sc). Because significant levels of infectivity have been detected in excrement from animals infected with scrapie and chronic wasting disease, studies on the dynamics of PrP(Sc) levels in contaminated soil are needed to assess the possible horizontal transmission of prion diseases. Using protein misfolding cyclic amplification, we developed a sensitive detection method for scrapie PrP(Sc) that is mixed with soil. Our detection method has the advantage of not requiring extraction of PrP(Sc) from soil and could provide a sensitivity 1000 to 10,000 times higher than that obtained with an extraction-based method. In addition, we found that PrP(Sc) levels in experimentally contaminated agricultural soils declined to different extents over the course of a 6-month incubation period. Our method appears to be a very useful technique for monitoring PrP(Sc) levels in soil.
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Affiliation(s)
- Kazunari Nagaoka
- Soil Microbiology Research Team, National Agricultural Research Center, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan
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21
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Davies P, Brown DR. Manganese enhances prion protein survival in model soils and increases prion infectivity to cells. PLoS One 2009; 4:e7518. [PMID: 19844576 PMCID: PMC2760146 DOI: 10.1371/journal.pone.0007518] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 09/30/2009] [Indexed: 11/18/2022] Open
Abstract
Prion diseases are considered to be transmissible. The existence of sporadic forms of prion diseases such as scrapie implies an environmental source for the infectious agent. This would suggest that under certain conditions the prion protein, the accepted agent of transmission, can survive in the environment. We have developed a novel technique to extract the prion protein from soil matrices. Previous studies have suggested that environmental manganese is a possible risk factor for prion diseases. We have shown that exposure to manganese is a soil matrix causes a dramatic increase in prion protein survival (∼10 fold) over a two year period. We have also shown that manganese increases infectivity of mouse passaged scrapie to culture cells by 2 logs. These results clearly verify that manganese is a risk factor for both the survival of the infectious agent in the environment and its transmissibility.
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Affiliation(s)
- Paul Davies
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - David R. Brown
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- * E-mail:
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22
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Saunders SE, Bartz JC, Bartelt-Hunt SL. Prion protein adsorption to soil in a competitive matrix is slow and reduced. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:7728-7733. [PMID: 19921886 DOI: 10.1021/es901385t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
It is likely that the soil environment serves as a stable reservoir of infectious CWD and scrapie prions as well as a potential reservoir of BSE. Prion adsorption to soil could play an important role in prion mobility, proteolysis, and infectivity. We modified previously published methods to quantify adsorbed prions via direct detection and studied prion adsorption to soil and soil minerals as a function of time through 60 days. Prion-infected brain homogenate was used as a complex, relevant prion source. We determined that maximum PrP adsorption requires days or weeks, depending on the soil or mineral, and is 2-5 orders of magnitude lower than previous studies using purified PrP(Sc) or recPrP. Because PrP adsorption to soil is slow and reduced in tissue homogenate, the possibility of prion transport in soil environments cannot be excluded and requires further investigation. Our results indicate that binding to soil may protect prions from degradation, consistent with prions' longevity in the environment. Adsorption of PrP to sterilized soil did not differ significantly from adsorption to unsterilized soil, which suggests that active biological processes do not significantly affect prion adsorption or degradation in the soil environment.
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Affiliation(s)
- Samuel E Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, USA
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23
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Johnson CJ, Gilbert PUPA, McKenzie D, Pedersen JA, Aiken JM. Ultraviolet-ozone treatment reduces levels of disease-associated prion protein and prion infectivity. BMC Res Notes 2009; 2:121. [PMID: 19580672 PMCID: PMC2714315 DOI: 10.1186/1756-0500-2-121] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 07/06/2009] [Indexed: 11/10/2022] Open
Abstract
Background Transmissible spongiform encephalopathies (TSEs) are a group of fatal neurodegenerative diseases caused by novel infectious agents referred to as prions. Prions appear to be composed primarily, if not exclusively, of a misfolded isoform of the cellular prion protein. TSE infectivity is remarkably stable and can resist many aggressive decontamination procedures, increasing human, livestock and wildlife exposure to TSEs. Findings We tested the hypothesis that UV-ozone treatment reduces levels of the pathogenic prion protein and inactivates the infectious agent. We found that UV-ozone treatment decreased the carbon and prion protein content in infected brain homogenate to levels undetectable by dry-ashing carbon analysis or immunoblotting, respectively. After 8 weeks of ashing, UV-ozone treatment reduced the infectious titer of treated material by a factor of at least 105. A small amount of infectivity, however, persisted despite UV-ozone treatment. When bound to either montmorillonite clay or quartz surfaces, PrPTSE was still susceptible to degradation by UV-ozone. Conclusion Our findings strongly suggest that UV-ozone treatment can degrade pathogenic prion protein and inactivate prions, even when the agent is associated with surfaces. Using larger UV-ozone doses or combining UV-ozone treatment with other decontaminant methods may allow the sterilization of TSE-contaminated materials.
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Affiliation(s)
- Christopher J Johnson
- Department of Comparative Biosciences, University of Wisconsin - Madison, 1656 Linden Dr, Madison, WI 53706, USA.
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24
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Jacobson KH, Lee S, McKenzie D, Benson CH, Pedersen JA. Transport of the pathogenic prion protein through landfill materials. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:2022-8. [PMID: 19368208 PMCID: PMC2796579 DOI: 10.1021/es802632d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Transmissible spongiform encephalopathies (TSEs, prion diseases) are a class of fatal neurodegenerative diseases affecting a variety of mammalian species including humans. A misfolded form of the prion protein (PrP(TSE)) is the major, if not sole, component of the infectious agent RecentTSE outbreaks in domesticated and wild animal populations have created the need for safe and effective disposal of large quantities of potentially infected materials. Here, we report results of a study to evaluate the potential for transport of PrP(TSE) derived from carcasses and associated wastes in municipal solid waste (MSW) landfills. Column experiments were conducted to evaluate PrP(TSE) transport in quartz sand, two fine-textured burial soils currently used in landfill practice, a green waste residual material (a potential burial material), and fresh and aged MSW. PrP(TSE) was retained by quartz sand and the fine-textured burial soils, with no detectable PrP(TSE) eluted over more than 40 pore volumes. In contrast, PrP(TSE) was more mobile in MSW and green waste residual. Transport parameters were estimated from the experimental data and used to model PrP(TSE) migration in a MSW landfill. To the extent that the PrP(TSE) used mimics that released from decomposing carcasses and the column experiments adequately simulate prion transport through burial soils, burial of CWD-infected materials at MSW landfills could provide secure containment of PrP(TSE) provided reasonable burial strategies (e.g., encasement in fine-grained soil) are used.
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Affiliation(s)
- Kurt H. Jacobson
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | - Seunghak Lee
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | - Debbie McKenzie
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706
| | - Craig H. Benson
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | - Joel A. Pedersen
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
- Department of Soil Science, University of Wisconsin, Madison, WI 53706
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25
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Russo F, Johnson CJ, Johnson CJ, McKenzie D, Aiken JM, Pedersen JA. Pathogenic prion protein is degraded by a manganese oxide mineral found in soils. J Gen Virol 2009; 90:275-80. [PMID: 19088299 DOI: 10.1099/vir.0.003251-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prions, the aetiological agents of transmissible spongiform encephalopathies, exhibit extreme resistance to degradation. Soil can retain prion infectivity in the environment for years. Reactive soil components may, however, contribute to the inactivation of prions in soil. Members of the birnessite family of manganese oxides (MnO(2)) rank among the strongest natural oxidants in soils. Here, we report the abiotic degradation of pathogenic prion protein (PrP(TSE)) by a synthetic analogue of naturally occurring birnessite minerals. Aqueous MnO(2) suspensions degraded the PrP(TSE) as evidenced by decreased immunoreactivity and diminished ability to seed protein misfolding cyclic amplification reactions. Birnessite-mediated PrP(TSE) degradation increased as a solution's pH decreased, consistent with the pH-dependence of the redox potential of MnO(2). Exposure to 5.6 mg MnO(2) ml(-1) (PrP(TSE) : MnO(2)=1 : 110) decreased PrP(TSE) levels by > or = 4 orders of magnitude. Manganese oxides may contribute to prion degradation in soil environments rich in these minerals.
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Affiliation(s)
- Fabio Russo
- Department of Soil Science and Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA
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26
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Rees HC, Maddison BC, Owen JP, Whitelam GC, Gough KC. Concentration of disease-associated prion protein with silicon dioxide. Mol Biotechnol 2008; 41:254-62. [PMID: 19058035 DOI: 10.1007/s12033-008-9129-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 11/15/2008] [Indexed: 11/24/2022]
Abstract
Reagents that can precipitate the disease-associated prion protein (PrP(Sc)) are vital for the development of high sensitivity tests to detect low levels of this disease marker in biological material. Here, a range of minerals are shown to precipitate both ovine cellular prion protein (PrP(C)) and ovine scrapie PrP(Sc). The precipitation of prion protein with silicon dioxide is unaffected by PrP(Sc) strain or host species and the method can be used to precipitate bovine BSE. This method can reliably concentrate protease-resistant ovine PrP(Sc) (PrP(res)) derived from 1.69 microg of brain protein from a clinically infected animal diluted into either 50 ml of buffer or 15 ml of plasma. The introduction of a SiO(2) precipitation step into the immunological detection of PrP(res) increased detection sensitivity by over 1,500-fold. Minerals such as SiO(2) are readily available, low cost reagents with generic application to the concentration of diseases-associated prion proteins.
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Affiliation(s)
- Helen C Rees
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
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27
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Saunders SE, Bartelt-Hunt SL, Bartz JC. Prions in the environment: occurrence, fate and mitigation. Prion 2008; 2:162-9. [PMID: 19242120 PMCID: PMC2658766 DOI: 10.4161/pri.2.4.7951] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 01/26/2009] [Indexed: 11/19/2022] Open
Abstract
Scrapie and CWD are horizontally transmissible, and the environment likely serves as a stable reservoir of infectious prions, facilitating a sustained incidence of CWD in free-ranging cervid populations and complicating efforts to eliminate disease in captive herds. Prions will enter the environment through mortalities and/or shedding from live hosts. Unfortunately, a sensitive detection method to identify prion contamination in environmental samples has not yet been developed. An environmentally-relevant prion model must be used in experimental studies. Changes in PrP(Sc) structure upon environmental exposure may be as significant as changes in PrP(Sc) quantity, since the structure can directly affect infectivity and disease pathology. Prions strongly bind to soil and remain infectious. Conformational changes upon adsorption, competitive sorption and potential for desorption and transport all warrant further investigation. Mitigation of contaminated carcasses or soil might be accomplished with enzyme treatments or composting in lieu of incineration.
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Affiliation(s)
- Samuel E Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska 68182-0178, USA
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28
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Saunders SE, Bartz JC, Telling GC, Bartelt-Hunt SL. Environmentally-relevant forms of the prion protein. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:6573-9. [PMID: 18800532 PMCID: PMC4480922 DOI: 10.1021/es800590k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Scrapie and chronic wasting disease (CWD) are prion diseases of particular environmental concern as they are horizontally transmissible and can remain infectious after years in the environment. Recent evidence suggests that the N-terminus of PrPSC, the infectious conformation of the prion protein, plays an important role in the mechanism of sorption to soil particles. We hypothesize that, in a prion-infected animal carcass, a portion of the N-terminus of PrPSc could be cleaved by proteinases in the brain at ordinary temperatures. Hamster (HY transmissible mink encephalopathy-infected), transgenic mice (CWD-infected), and elk (CWD-infected) brain homogenates were incubated at 22 and 37 degrees C for up to 1 month and then analyzed by Western blot using N-terminal and middle region monoclonal anti-PrP antibodies. For all three systems, there was a very faint or undetectable N-terminal PrP signal after 35 days at both temperatures, which indicates that full-length PrPSc might be rare in the brain matter of animal carcasses. Future studies on prion-soil interactions should therefore consider N-terminal-degraded PrPSc in addition to the full-length form. Both mouse and elk CWD PrPSc demonstrated greater resistance to degradation than HY TME PrPSc. This indicates that the transgenic mouse-CWD model is a good surrogate for natural CWD prions, but that other rodent prion models might not accurately represent CWD prion fate in the environment.
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Affiliation(s)
- Samuel E. Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, United States of America
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Glenn C. Telling
- Department of Microbiology, Immunology and Molecular Genetics, Department of Neurology, Sanders Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Shannon L. Bartelt-Hunt
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, United States of America
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29
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Johnson CJ, Pedersen JA, Chappell RJ, McKenzie D, Aiken JM. Oral transmissibility of prion disease is enhanced by binding to soil particles. PLoS Pathog 2008; 3:e93. [PMID: 17616973 PMCID: PMC1904474 DOI: 10.1371/journal.ppat.0030093] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Accepted: 05/17/2007] [Indexed: 01/13/2023] Open
Abstract
Soil may serve as an environmental reservoir for prion infectivity and contribute to the horizontal transmission of prion diseases (transmissible spongiform encephalopathies [TSEs]) of sheep, deer, and elk. TSE infectivity can persist in soil for years, and we previously demonstrated that the disease-associated form of the prion protein binds to soil particles and prions adsorbed to the common soil mineral montmorillonite (Mte) retain infectivity following intracerebral inoculation. Here, we assess the oral infectivity of Mte- and soil-bound prions. We establish that prions bound to Mte are orally bioavailable, and that, unexpectedly, binding to Mte significantly enhances disease penetrance and reduces the incubation period relative to unbound agent. Cox proportional hazards modeling revealed that across the doses of TSE agent tested, Mte increased the effective infectious titer by a factor of 680 relative to unbound agent. Oral exposure to Mte-associated prions led to TSE development in experimental animals even at doses too low to produce clinical symptoms in the absence of the mineral. We tested the oral infectivity of prions bound to three whole soils differing in texture, mineralogy, and organic carbon content and found soil-bound prions to be orally infectious. Two of the three soils increased oral transmission of disease, and the infectivity of agent bound to the third organic carbon-rich soil was equivalent to that of unbound agent. Enhanced transmissibility of soil-bound prions may explain the environmental spread of some TSEs despite the presumably low levels shed into the environment. Association of prions with inorganic microparticles represents a novel means by which their oral transmission is enhanced relative to unbound agent. Transmissible spongiform encephalopathies (TSEs) are a group of incurable neurological diseases likely caused by a misfolded form of the prion protein. TSEs include scrapie in sheep, bovine spongiform encephalopathy (“mad cow” disease) in cattle, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in humans. Scrapie and chronic wasting disease are unique among TSEs because they can be transmitted between animals, and the disease agents appear to persist in environments previously inhabited by infected animals. Soil has been hypothesized to act as a reservoir of infectivity and to bind the infectious agent. In the current study, we orally dosed experimental animals with a common clay mineral, montmorillonite, or whole soils laden with infectious prions, and compared the transmissibility to unbound agent. We found that prions bound to montmorillonite and whole soils remained orally infectious, and, in most cases, increased the oral transmission of disease compared to the unbound agent. The results presented in this study suggest that soil may contribute to environmental spread of TSEs by increasing the transmissibility of small amounts of infectious agent in the environment.
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Affiliation(s)
- Christopher J Johnson
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Joel A Pedersen
- Department of Soil Science and Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Rick J Chappell
- Biostatistics and Medical Informatics, University of Wisconsin Medical School, Madison, Wisconsin, United States of America
| | - Debbie McKenzie
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Judd M Aiken
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * To whom correspondence should be addressed. E-mail:
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Pucci A, D'Acqui LP, Calamai L. Fate of prions in soil: interactions of RecPrP with organic matter of soil aggregates as revealed by LTA-PAS. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:728-733. [PMID: 18323094 DOI: 10.1021/es071314q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The contribution of soil organic matter (OM) to the adsorption of a recombinant prion protein (RecPrP) was studied in microcosm systems (soil aggregates from two different soils) before and after OM removal by low temperature ashing (LTA). The LTA technique allows a controlled removal of OM layer by layer, like a peeling of an onion skin, with minimal disturbance of the mineral matrix. Soil aggregates were selected as a representative model of the "in situ" conditions. Adsorption from batch vs percolation experiments were compared, and the aggregates were characterized by photoacustic Fourier-transform IR spectroscopy (PAS-FTIR). High affinity (H-type) adsorption isotherms were found with complete removal of RecPrP from solution for protein/soil ratios up to 1:62.5. OM removal from aggregates decreased the adsorbed RecPrP in amounts corresponding to 330-1000 microg mg(-1) of soil organic carbon (OC) indicating that native OM has specific adsorption capacity comparable and/or superior to the mineral matrix. The coupled LTA-PAS-FTIR approach demonstrated that, albeit OM composition was homogeneous throughout the aggregates, its presence in the most external surfaces of the aggregates affects the diffusion dynamics of RecPrP within the aggregates during percolation.
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Affiliation(s)
- Amaranta Pucci
- Dipartimento di Scienza del Suolo e Nutrizione della Pianta, Università degli Studi di Firenze, Piazzale delle Cascine 28, 50144 Firenze, Italy.
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Genovesi S, Leita L, Sequi P, Andrighetto I, Sorgato MC, Bertoli A. Direct detection of soil-bound prions. PLoS One 2007; 2:e1069. [PMID: 17957252 PMCID: PMC2031919 DOI: 10.1371/journal.pone.0001069] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 10/02/2007] [Indexed: 11/18/2022] Open
Abstract
Scrapie and chronic wasting disease are contagious prion diseases affecting sheep and cervids, respectively. Studies have indicated that horizontal transmission is important in sustaining these epidemics, and that environmental contamination plays an important role in this. In the perspective of detecting prions in soil samples from the field by more direct methods than animal-based bioassays, we have developed a novel immuno-based approach that visualises in situ the major component (PrPSc) of prions sorbed onto agricultural soil particles. Importantly, the protocol needs no extraction of the protein from soil. Using a cell-based assay of infectivity, we also report that samples of agricultural soil, or quartz sand, acquire prion infectivity after exposure to whole brain homogenates from prion-infected mice. Our data provide further support to the notion that prion-exposed soils retain infectivity, as recently determined in Syrian hamsters intracerebrally or orally challanged with contaminated soils. The cell approach of the potential infectivity of contaminated soil is faster and cheaper than classical animal-based bioassays. Although it suffers from limitations, e.g. it can currently test only a few mouse prion strains, the cell model can nevertheless be applied in its present form to understand how soil composition influences infectivity, and to test prion-inactivating procedures.
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Affiliation(s)
- Sacha Genovesi
- Dipartimento di Chimica Biologica, Università di Padova, Padova, Italy
| | - Liviana Leita
- Istituto Sperimentale per la Nutrizione delle Piante, Gorizia, Italy
| | - Paolo Sequi
- Istituto Sperimentale per la Nutrizione delle Piante, Roma, Italy
| | | | - M. Catia Sorgato
- Dipartimento di Chimica Biologica, Università di Padova, Padova, Italy
- CNR Istituto di Neuroscienze, Padova, Italy
| | - Alessandro Bertoli
- Dipartimento di Chimica Biologica, Università di Padova, Padova, Italy
- * To whom correspondence should be addressed. E-mail:
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Seidel B, Thomzig A, Buschmann A, Groschup MH, Peters R, Beekes M, Terytze K. Scrapie Agent (Strain 263K) can transmit disease via the oral route after persistence in soil over years. PLoS One 2007; 2:e435. [PMID: 17502917 PMCID: PMC1855989 DOI: 10.1371/journal.pone.0000435] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 04/18/2007] [Indexed: 11/19/2022] Open
Abstract
The persistence of infectious biomolecules in soil constitutes a substantial challenge. This holds particularly true with respect to prions, the causative agents of transmissible spongiform encephalopathies (TSEs) such as scrapie, bovine spongiform encephalopathy (BSE), or chronic wasting disease (CWD). Various studies have indicated that prions are able to persist in soil for years without losing their pathogenic activity. Dissemination of prions into the environment can occur from several sources, e.g., infectious placenta or amniotic fluid of sheep. Furthermore, environmental contamination by saliva, excrements or non-sterilized agricultural organic fertilizer is conceivable. Natural transmission of scrapie in the field seems to occur via the alimentary tract in the majority of cases, and scrapie-free sheep flocks can become infected on pastures where outbreaks of scrapie had been observed before. These findings point to a sustained contagion in the environment, and notably the soil. By using outdoor lysimeters, we simulated a contamination of standard soil with hamster-adapted 263K scrapie prions, and analyzed the presence and biological activity of the soil-associated PrPSc and infectivity by Western blotting and hamster bioassay, respectively. 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.
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Affiliation(s)
- Bjoern Seidel
- Fraunhofer Institute for Molecular Biology und Applied Ecology (IME), Schmallenberg, Germany.
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