1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Dehydration of Prions on Environmentally Relevant Surfaces Protects Them from Inactivation by Freezing and Thawing. J Virol 2018; 92:JVI.02191-17. [PMID: 29386284 DOI: 10.1128/jvi.02191-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 01/24/2018] [Indexed: 11/20/2022] Open
Abstract
Chronic wasting disease (CWD) is an emerging prion disease in North America. Recent identification of CWD in wild cervids from Norway raises the concern of the spread of CWD in Europe. CWD infectivity can enter the environment through live animal excreta and carcasses where it can bind to soil. Well-characterized hamster prion strains and CWD field isolates in unadsorbed or soil-adsorbed forms that were either hydrated or dehydrated were subjected to repeated rounds of freezing and thawing. We found that 500 cycles of repeated freezing and thawing of hydrated samples significantly decreased the abundance of PrPSc and reduced protein misfolding cyclic amplification (PMCA) seeding activity that could be rescued by binding to soil. Importantly, dehydration prior to freezing and thawing treatment largely protected PrPSc from degradation, and the samples maintained PMCA seeding activity. We hypothesize that redistribution of water molecules during the freezing and thawing process alters the stability of PrPSc aggregates. Overall, these results have significant implications for the assessment of prion persistence in the environment.IMPORTANCE Prions excreted into the environment by infected animals, such as elk and deer infected with chronic wasting disease, persist for years and thus facilitate horizontal transmission of the disease. Understanding the fate of prions in the environment is essential to control prion disease transmission. The significance of our study is that it provides information on the possibility of prion degradation and inactivation under natural weathering processes. This information is significant for remediation of prion-contaminated environments and development of prion disease control strategies.
Collapse
|
3
|
Donaldson DS, Mabbott NA. The influence of the commensal and pathogenic gut microbiota on prion disease pathogenesis. J Gen Virol 2016; 97:1725-1738. [PMID: 27193137 DOI: 10.1099/jgv.0.000507] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Prion diseases are a unique group of transmissible, chronic, neurodegenerative disorders. Following peripheral exposure (e.g. oral), prions often accumulate first within the secondary lymphoid tissues before they infect the central nervous system (CNS). Prion replication within secondary lymphoid tissues is crucial for the efficient spread of disease to the CNS. Once within the CNS, the responses of innate immune cells within it can have a significant influence on neurodegeneration and disease progression. Recently, there have been substantial advances in our understanding of how cross-talk between the host and the vast community of commensal microorganisms present at barrier surfaces such as the gut influences the development and regulation of the host's immune system. These effects are evident not only in the mucosal immune system in the gut, but also in the CNS. The actions of this microbial community (the microbiota) have many important beneficial effects on host health, from metabolism of nutrients and regulation of host development to protection from pathogen infection. However, the microbiota can also have detrimental effects in some circumstances. In this review we discuss the many and varied interactions between prions, the host and the gut microbiota. Particular emphasis is given to the ways by which changes to the composition of the commensal gut microbiota or congruent pathogen infection may influence prion disease pathogenesis and/or disease susceptibility. Understanding how these factors influence prion pathogenesis and disease susceptibility is important for assessing the risk to infection and the design of novel opportunities for therapeutic intervention.
Collapse
Affiliation(s)
- David S Donaldson
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, UK
| | - Neil A Mabbott
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
4
|
Yuan Q, Eckland T, Telling G, Bartz J, Bartelt-Hunt S. Mitigation of prion infectivity and conversion capacity by a simulated natural process--repeated cycles of drying and wetting. PLoS Pathog 2015; 11:e1004638. [PMID: 25665187 PMCID: PMC4335458 DOI: 10.1371/journal.ppat.1004638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 12/19/2014] [Indexed: 11/24/2022] Open
Abstract
Prions enter the environment from infected hosts, bind to a wide range of soil and soil minerals, and remain highly infectious. Environmental sources of prions almost certainly contribute to the transmission of chronic wasting disease in cervids and scrapie in sheep and goats. While much is known about the introduction of prions into the environment and their interaction with soil, relatively little is known about prion degradation and inactivation by natural environmental processes. In this study, we examined the effect of repeated cycles of drying and wetting on prion fitness and determined that 10 cycles of repeated drying and wetting could reduce PrPSc abundance, PMCA amplification efficiency and extend the incubation period of disease. Importantly, prions bound to soil were more susceptible to inactivation by repeated cycles of drying and wetting compared to unbound prions, a result which may be due to conformational changes in soil-bound PrPSc or consolidation of the bonding between PrPSc and soil. This novel finding demonstrates that naturally-occurring environmental process can degrade prions. Prion diseases such as chronic wasting disease and scrapie are emerging in North America at an increasing rate. Infectious prions are introduced into the environment from both living and dead animals where they can bind to soil. Little information is available on the effect of prion inactivation under conditions that would be found in the natural environment. In this study, we exposed both unbound and soil-bound prions to repeated cycles of drying and wetting to simulate ambient environmental conditions. We found evidence of prion inactivation in both unbound and soil bound prions. The influence of repeated cycles of drying and wetting are dependent on the prion strain and soil type used and, interestingly, prions bound to soil were more susceptible to inactivation. This is the first report of natural environmental processes mitigating prion infectivity. This data suggests that the total environmental prion load is a balance between input and natural clearance.
Collapse
Affiliation(s)
- Qi Yuan
- Department of Civil Engineering, Peter Kiewit Institute, University of Nebraska-Lincoln, Omaha, Nebraska, United States of America
| | - Thomas Eckland
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Glenn Telling
- Department of Microbiology, Immunology and Pathology, Prion Research Center, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jason Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- * E-mail: (JB); (SBH)
| | - Shannon Bartelt-Hunt
- Department of Civil Engineering, Peter Kiewit Institute, University of Nebraska-Lincoln, Omaha, Nebraska, United States of America
- * E-mail: (JB); (SBH)
| |
Collapse
|
5
|
VerCauteren KC, Pilon JL, Nash PB, Phillips GE, Fischer JW. Prion remains infectious after passage through digestive system of American crows (Corvus brachyrhynchos). PLoS One 2012; 7:e45774. [PMID: 23082115 PMCID: PMC3474818 DOI: 10.1371/journal.pone.0045774] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 08/24/2012] [Indexed: 11/19/2022] Open
Abstract
Avian scavengers, such as American crows (Corvus brachyrhynchos), have potential to translocate infectious agents (prions) of transmissible spongiform encephalopathy (TSE) diseases including chronic wasting disease, scrapie, and bovine spongiform encephalopathy. We inoculated mice with fecal extracts obtained from 20 American crows that were force-fed material infected with RML-strain scrapie prions. These mice all evinced severe neurological dysfunction 196–231 d postinoculation ( = 198; 95% CI: 210–216) and tested positive for prion disease. Our results suggest a large proportion of crows that consume prion-positive tissue are capable of passing infectious prions in their feces ( = 1.0; 95% CI: 0.8–1.0). Therefore, this common, migratory North American scavenger could play a role in the geographic spread of TSE diseases.
Collapse
Affiliation(s)
- Kurt C VerCauteren
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA.
| | | | | | | | | |
Collapse
|
6
|
Saunders SE, Bartelt-Hunt SL, Bartz JC. Resistance of soil-bound prions to rumen digestion. PLoS One 2012; 7:e44051. [PMID: 22937149 PMCID: PMC3427226 DOI: 10.1371/journal.pone.0044051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 07/27/2012] [Indexed: 11/18/2022] Open
Abstract
Before prion uptake and infection can occur in the lower gastrointestinal system, ingested prions are subjected to anaerobic digestion in the rumen of cervids and bovids. The susceptibility of soil-bound prions to rumen digestion has not been evaluated previously. In this study, prions from infectious brain homogenates as well as prions bound to a range of soils and soil minerals were subjected to in vitro rumen digestion, and changes in PrP levels were measured via western blot. Binding to clay appeared to protect noninfectious hamster PrPc from complete digestion, while both unbound and soil-bound infectious PrPSc proved highly resistant to rumen digestion. In addition, no change in intracerebral incubation period was observed following active rumen digestion of unbound hamster HY TME prions and HY TME prions bound to a silty clay loam soil. These results demonstrate that both unbound and soil-bound prions readily survive rumen digestion without a reduction in infectivity, further supporting the potential for soil-mediated transmission of chronic wasting disease (CWD) and scrapie in the environment.
Collapse
Affiliation(s)
- Samuel E. Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska, 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
- * E-mail:
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| |
Collapse
|
7
|
Susceptibility of young sheep to oral infection with bovine spongiform encephalopathy decreases significantly after weaning. J Virol 2012; 86:11856-62. [PMID: 22915816 DOI: 10.1128/jvi.01573-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) (or prion disease) that is readily transmissible to sheep by experimental infection and has the shortest incubation period in animals with the ARQ/ARQ PRNP genotype (at codons 136, 154, and 171). Because it is possible that sheep in the United Kingdom could have been infected with BSE by being fed contaminated meat and bone meal supplements at the same time as cattle, there is considerable interest in the responses of sheep to BSE inoculation. Epidemiological evidence suggests that very young individuals are more susceptible to TSE infection; however, this has never been properly tested in sheep. In the present study, low doses of BSE were fed to lambs of a range of ages (~24 h, 2 to 3 weeks, 3 months, and 6 months) and adult sheep. The incidence of clinical BSE disease after inoculation was high in unweaned lambs (~24 h and 2 to 3 weeks old) but much lower in older weaned animals The incubation period was also found to be influenced by the genotype at codon 141 of the PRNP gene, as lambs that were LF heterozygotes had a longer mean incubation period than those that were homozygotes of either type. The results suggest that sheep in the United Kingdom would have been at high risk of BSE infection only if neonatal animals had inadvertently ingested contaminated supplementary foodstuffs.
Collapse
|
8
|
Böhnlein C, Groschup MH, Maertlbauer E, Pichner R, Gareis M. Stability of bovine spongiform encephalopathy prions: absence of prion protein degradation by bovine gut microbiota. Zoonoses Public Health 2012; 59:251-5. [PMID: 22353543 DOI: 10.1111/j.1863-2378.2012.01455.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bovine spongiform encephalopathy (BSE) is transmitted by the oral route. However, the impacts of anaerobic fermentation processes in cattle on the stability of BSE-associated prion protein (PrP(Sc)) are still unresolved. In this study, experiments were designed to assess the ability of complex ruminal and colonic contents of bovines to degrade BSE-derived PrP(Sc). No significant decrease in PrP(Sc) levels in BSE brain homogenates was detected by Western blotting after up to 66 h of co-incubation with intestinal fluids. These results indicate that BSE-associated PrP(Sc) survive gastrointestinal digestion processes in cattle and might be excreted via faeces.
Collapse
Affiliation(s)
- C Böhnlein
- Institute for Microbiology and Biotechnology, Max-Rubner-Institute, Federal Research Institute for Nutrition and Food, Kulmbach, Germany.
| | | | | | | | | |
Collapse
|
9
|
Takakura I, Miyazawa K, Kanaya T, Itani W, Watanabe K, Ohwada S, Watanabe H, Hondo T, Rose MT, Mori T, Sakaguchi S, Nishida N, Katamine S, Yamaguchi T, Aso H. Orally administered prion protein is incorporated by m cells and spreads into lymphoid tissues with macrophages in prion protein knockout mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1301-9. [PMID: 21763679 DOI: 10.1016/j.ajpath.2011.05.058] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 05/13/2011] [Accepted: 05/23/2011] [Indexed: 12/21/2022]
Abstract
Transmissible spongiform encephalopathies are fatal neurodegenerative diseases. Infection by the oral route is assumed to be important, although its pathogenesis is not understood. Using prion protein (PrP) knockout mice, we investigated the sequence of events during the invasion of orally administered PrPs through the intestinal mucosa and the spread into lymphoid tissues and the peripheral nervous system. Orally administered PrPs were incorporated by intestinal epitheliocytes in the follicle-associated epithelium and villi within 1 hour. PrP-positive cells accumulated in the subfollicle region of Peyer's patches a few hours thereafter. PrP-positive cells spread toward the mesenteric lymph nodes and spleen after the accumulation of PrPs in the Peyer's patches. The number of PrP molecules in the mesenteric lymph nodes and spleen peaked at 2 days and 6 days after inoculation, respectively. The epitheliocytes in the follicle-associated epithelium incorporating PrPs were annexin V-positive microfold cells and PrP-positive cells in Peyer's patches and spleen were CD11b-positive and CD14-positive macrophages. Additionally, PrP-positive cells in Peyer's patches and spleen were detected in the vicinity of peripheral nerve fibers in the early stages of infection. These results indicate that orally delivered PrPs were incorporated by microfold cells promptly after challenge and that macrophages might act as a transporter of incorporated PrPs from the Peyer's patches to other lymphoid tissues and the peripheral nervous system.
Collapse
Affiliation(s)
- Ikuro Takakura
- Cellular Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Urayama A, Morales R, Niehoff ML, Banks WA, Soto C. Initial fate of prions upon peripheral infection: half-life, distribution, clearance, and tissue uptake. FASEB J 2011; 25:2792-803. [PMID: 21555356 DOI: 10.1096/fj.11-180729] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prion diseases are infectious neurodegenerative disorders associated with the misfolded prion protein (PrP(Sc)), which appears to be the sole component of the infectious agent (termed prion). To produce disease, prions have to be absorbed into the body and reach sufficient quantities in the brain. Very little is known about the biological mechanisms controlling the initial fate of prions. Here, we studied the systemic pharmacokinetics and biodistribution of PrP(Sc) in vivo. After an intravenous injection of highly purified radiolabeled or native unlabeled PrP(Sc), the protein was eliminated rapidly from the serum (half-life of 3.24 h), mostly through tissue uptake. The quantity of intact PrP(Sc) reaching the brain was ∼ 0.2% of the injected dose per gram of brain tissue (ID/g). The highest levels were found in liver (∼ 20% ID/g), spleen (∼ 13% ID/g), and kidney (∼ 7.4% ID/g). Cell surface PrP(C) does not appear to play a role in PrP(Sc) pharmacokinetics, since the infectious protein distributed similarly in wild-type and PrP-null mice. To measure tissue uptake kinetics and biodistribution accurately, vascular space in tissues was measured with radioactively labeled albumin coinjected with radioactively labeled PrP(Sc). Our results provide a fundamental pharmacokinetic characterization of PrP(Sc) in vivo, which may be relevant to estimate tissue risks and mechanisms of prion neuroinvasion and to identify novel therapeutic strategies.
Collapse
Affiliation(s)
- Akihiko Urayama
- Department of Neurology, The University of Texas Medical School at Houston, Houston, Texas 77030, USA.
| | | | | | | | | |
Collapse
|
11
|
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.
Collapse
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
| | | |
Collapse
|
12
|
Bastian FO, Boudreaux CM, Hagius SD, Bulgin MS, Sorensen-Melson SJ, Enright FM, Elzer PH. Spiroplasma found in the eyes of scrapie affected sheep. Vet Ophthalmol 2011; 14:10-7. [DOI: 10.1111/j.1463-5224.2010.00833.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
13
|
Dagleish MP, Hamilton S, González L, Eaton SL, Steele P, Finlayson J, Sisó S, Pang Y, Sales J, Chianini F, Jeffrey M. Digestion and transportation of bovine spongiform encephalopathy-derived prion protein in the sheep intestine. J Gen Virol 2010; 91:3116-23. [PMID: 20826616 DOI: 10.1099/vir.0.025049-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bovine spongiform encephalopathy (BSE) is acquired orally and the mechanisms involved in the absorption and transportation of infectivity across the gut wall are therefore critical. Isolated gut loops were created in lambs, massaged to remove intestinal contents (flushed) or left non-flushed, inoculated with cattle BSE homogenate and excised at different time-points. Gut loops were examined by immunohistochemistry (IHC) for disease-associated prion protein (PrP(d)), and the contents were analysed by Western blotting (WB) to determine the degradation rate of protease-resistant PrP (PrP(res)). The contents of scrapie-inoculated gut loops from a previous experiment were analysed by WB, and these in vivo digestion results were compared with those of an in vitro experiment on the same transmissible spongiform encephalopathy homogenates. BSE-inoculum-derived PrP(d) was detected by IHC in the gut lumen between 15 min and 3.5 h. It was found in the intestinal lymphatic system from 30 min onwards and was present at the highest frequency at 120 min post-inoculation. In vivo degradation of PrP(res) in the BSE inoculum had a significantly (P=0.006) different pattern compared with scrapie-derived PrP(res), with the BSE PrP(res) degrading more rapidly. However, the overall amount of degradation became similar by 120 min post-challenge. The results of the in vitro digestion experiments showed a similar pattern, although the magnitude of PrP(res) degradation was less than in the in vivo environment where absorption could also take place. BSE-derived PrP(res) is less protease resistant than scrapie PrP over a short time-course and the disappearance of detectable PrP(res) from the gut lumen results from both absorption and digestion by intestinal contents.
Collapse
Affiliation(s)
- Mark P Dagleish
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Saunders SE, Bartz JC, Vercauteren KC, Bartelt-Hunt SL. Enzymatic digestion of chronic wasting disease prions bound to soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:4129-4135. [PMID: 20450190 PMCID: PMC2885836 DOI: 10.1021/es903520d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Chronic wasting disease (CWD) and sheep scrapie can be transmitted via indirect environmental routes, and it is known that soil can serve as a reservoir of prion infectivity. Given the strong interaction between the prion protein (PrP) and soil, we hypothesized that binding to soil enhances prion resistance to enzymatic digestion, thereby facilitating prion longevity in the environment and providing protection from host degradation. We characterized the performance of a commercially available subtilisin enzyme, Prionzyme, to degrade soil-bound and unbound CWD and HY TME PrP as a function of pH, temperature, and treatment time. The subtilisin enzyme effectively degraded PrP adsorbed to a wide range of soils and soil minerals below the limits of detection. Signal loss occurred rapidly at high pH (12.5) and within 7 days under conditions representative of the natural environment (pH 7.4, 22 degrees C). We observed no apparent difference in enzyme effectiveness between bound and unbound CWD PrP. Our results show that although adsorbed prions do retain relative resistance to enzymatic digestion compared with other brain homogenate proteins, they can be effectively degraded when bound to soil. Our results also suggest a topical application of a subtilisin enzyme solution may be an effective decontamination method to limit disease transmission via environmental "hot spots" of prion infectivity.
Collapse
Affiliation(s)
- Samuel E Saunders
- Department of Civil Engineering, Peter Kiewit Institute, University of Nebraska-Lincoln, Omaha, Nebraska 68588, USA.
| | | | | | | |
Collapse
|
15
|
Pilon JL, Nash PB, Arver T, Hoglund D, Vercauteren KC. Feasibility of infectious prion digestion using mild conditions and commercial subtilisin. J Virol Methods 2009; 161:168-72. [PMID: 19467265 DOI: 10.1016/j.jviromet.2009.04.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 01/22/2009] [Accepted: 04/28/2009] [Indexed: 11/29/2022]
Abstract
Two serine protease enzymes, subtilisin 309 and subtilisin 309-v, were used to digest brain homogenates containing high levels of prion infectivity using mildly alkaline conditions to investigate prion decontamination methods. To establish that PrP(res) infectivity was eliminated, we utilized the Rocky Mountain Laboratory (RML) mouse-adapted scrapie model system for bioassay. Only one digestion condition (subtilisin 309 at 138mAU/ml, 55 degrees C and 14h digestion time pH 7.9) was considered to be highly relevant statistically (P<0.001) compared to control, with 52% of challenged mice surviving until the end of the study period. In contrast, treatment of PrP(res) by autoclaving at 134 degrees C or treatment with hypochlorite at a concentration of 20,000 ppm completely protected mice from prionosis. Further, in vitro assays suggest that potential proteolytic based PrP(res) decontamination methods must use high enzyme concentration, pH values >9.0, and elevated temperatures to be a safely efficacious, thereby limiting applicability on delicate surgical instruments and use in the environment.
Collapse
Affiliation(s)
- John L Pilon
- National Wildlife Research Center, 4101 Laporte Ave., Fort Collins, CO 80521, USA.
| | | | | | | | | |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- Samuel E Saunders
- Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska 68182-0178, USA
| | | | | |
Collapse
|
17
|
Hinckley GT, Johnson CJ, Jacobson KH, Bartholomay C, McMahon KD, McKenzie D, Aiken JM, Pedersen JA. Persistence of pathogenic prion protein during simulated wastewater treatment processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:5254-9. [PMID: 18754377 PMCID: PMC3087203 DOI: 10.1021/es703186e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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. Prions are highly resistant to degradation and to many disinfection procedures suggesting that, if prions enter wastewater treatment systems through sewers and/or septic systems (e.g., from slaughterhouses, necropsy laboratories, rural meat processors, private game dressing) or through leachate from landfills that have received TSE-contaminated material, prions could survive conventional wastewater treatment. Here, we report the results of experiments examining the partitioning and persistence of PrPTSE during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion. Incubation with activated sludge did not result in significant PrPTSE degradation. PrPTSE and prion infectivity partitioned strongly to activated sludge solids and are expected to enter biosolids treatment processes. A large fraction of PrPTSE survived simulated mesophilic anaerobic sludge digestion. The small reduction in recoverable PrPTSE after 20-d anaerobic sludge digestion appeared attributable to a combination of declining extractability with time and microbial degradation. Our results suggest that if prions were to enter municipal wastewater treatment systems, most would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in treated biosolids.
Collapse
Affiliation(s)
- Glen T. Hinckley
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | | | - Kurt H. Jacobson
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | | | - Katherine D. McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706
| | - Debbie McKenzie
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706
| | - Judd M. Aiken
- Department of Comparative Biosciences, 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
- Corresponding author address: Department of Soil Science, University of Wisconsin, 1525 Observatory Drive, Madison, WI 53706-1299; phone: (608) 263-4971; fax: (608) 265-2595; e-mail:
| |
Collapse
|
18
|
Scherbel C, Pichner R, Groschup MH, Mueller-Hellwig S, Scherer S, Dietrich R, Maertlbauer E, Gareis M. Infectivity of scrapie prion protein (PrPSc) following in vitro digestion with bovine gastrointestinal microbiota. Zoonoses Public Health 2007; 54:185-90. [PMID: 17542960 DOI: 10.1111/j.1863-2378.2007.01040.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The influence of a complex microflora residing in the gastrointestinal tract of cattle on the prion protein plays a crucial role with respect to early pathogenesis and the potential infectivity of faeces resulting in contamination of the environment. It is unknown whether infectious prion proteins, considered to be very stable, are inactivated by microbial processes in the gastrointestinal tract of animals during digestion. In our previous study it was shown that the scrapie-associated prion protein was degraded by ruminal and colonic microbiota of cattle, as indicated by a loss of anti-prion antibody 3F4 immunoreactivity in Western blot. Subsequently, in this study hamster bioassays with the pre-treated samples were performed. Although the PrP(Sc) signal was reduced up to immunochemically undetectable levels within 40 h of pre-treatment, significant residual prion infectivity was retained after degradation of infected hamster brain through the gastrointestinal microflora of cattle. The data presented here show that the loss of anti-prion antibody 3F4 immunoreactivity is obviously not correlated with a biological inactivation of PrP(Sc). These results highlight the deficiency of using Western blot in transmissible spongiform encephalopathies inactivation assessment studies and, additionally, point to the possibility of environmental contamination with faeces containing PrP(Sc) following an oral ingestion of prions.
Collapse
Affiliation(s)
- C Scherbel
- Institute for Microbiology and Toxicology, Federal Research Centre for Nutrition and Food, Kulmbach, Germany
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Nicholson EM, Richt JA, Rasmussen MA, Hamir AN, Lebepe-Mazur S, Horst RL. Exposure of sheep scrapie brain homogenate to rumen-simulating conditions does not result in a reduction of PrPSclevels. Lett Appl Microbiol 2007; 44:631-6. [PMID: 17576225 DOI: 10.1111/j.1472-765x.2007.02124.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AIMS Experiments were designed to evaluate the potential of rumen-simulating conditions to reduce PrP(Sc) levels. METHODS AND RESULTS Scrapie-positive brain material was incubated under rumen-simulating conditions. Time points were taken over a 24-h period and PrP(Sc) levels were analysed by Western blot. No loss of PrP(Sc) was observed over a 24-h time period. CONCLUSIONS Our results indicate that a fully developed rumen fermentation does not provide significant protection against prion infection via the oral route. Developmental changes including senescence of immune system function or other developmental changes in the gastrointestinal tract are potential mechanisms by which relative bovine spongiform encephalopathy (BSE) susceptibility might vary with age. SIGNIFICANCE AND IMPACT OF THE STUDY Epidemiology of the BSE outbreak in the United Kingdom indicates that younger animals were at higher risk of infection. The rumen undergoes pronounced developmental changes early in life, coinciding with the introduction of fibre into the diet. The timeframe of highest risk of infection overlaps the time in life prior to full rumen development. This work indicates that a fully developed rumen does not provide significant protection against prion infection via the oral route of infection. This result implicates other developmental changes that are responsible for the age-dependent susceptibility of cattle to BSE.
Collapse
Affiliation(s)
- E M Nicholson
- Virus and Prion Diseases of Livestock Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, Ames, IA 50010, USA.
| | | | | | | | | | | |
Collapse
|
20
|
Bade S, Frey A. Potential of active and passive immunizations for the prevention and therapy of transmissible spongiform encephalopathies. Expert Rev Vaccines 2007; 6:153-68. [PMID: 17408366 DOI: 10.1586/14760584.6.2.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transmissible spongiform encephalopathies are fatal neurodegenerative disorders that affect humans and certain animals and are caused by prions. In most cases, infection occurs by ingestion of prions. Their long-time persistence in the environment creates a reservoir of potentially infectious matter that renders the eradication of the disease problematic. Unfortunately, no cure is available to date. Yet, for both the treatment of infected and the protection of uninfected individuals, active and passive immunizations have been shown to have a beneficial effect on the course of the disease. The current review provides an overview of such antibody-based approaches and assesses their feasibility and potential in prophylaxis and therapy of transmissible spongiform encephalopathies.
Collapse
Affiliation(s)
- Steffen Bade
- Research Center Borstel, Division of Mucosal Immunology, Borstel, Germany.
| | | |
Collapse
|
21
|
Mathiason CK, Powers JG, Dahmes SJ, Osborn DA, Miller KV, Warren RJ, Mason GL, Hays SA, Hayes-Klug J, Seelig DM, Wild MA, Wolfe LL, Spraker TR, Miller MW, Sigurdson CJ, Telling GC, Hoover EA. Infectious prions in the saliva and blood of deer with chronic wasting disease. Science 2006; 314:133-6. [PMID: 17023660 DOI: 10.1126/science.1132661] [Citation(s) in RCA: 343] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A critical concern in the transmission of prion diseases, including chronic wasting disease (CWD) of cervids, is the potential presence of prions in body fluids. To address this issue directly, we exposed cohorts of CWD-naïve deer to saliva, blood, or urine and feces from CWD-positive deer. We found infectious prions capable of transmitting CWD in saliva (by the oral route) and in blood (by transfusion). The results help to explain the facile transmission of CWD among cervids and prompt caution concerning contact with body fluids in prion infections.
Collapse
Affiliation(s)
- Candace K Mathiason
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biological Sciences (CVMBS), Colorado State University (CSU), Fort Collins, CO 80523, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|