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Soto P, Bravo-Risi F, Benavente R, Stimming TH, Bodenchuk MJ, Whitley P, Turnage C, Spraker TR, Greenlee J, Telling G, Malmberg J, Gidlewski T, Nichols T, Brown VR, Morales R. Detection of Prions in Wild Pigs (Sus scrofa) from Areas with Reported Chronic Wasting Disease Cases, United States. Emerg Infect Dis 2025; 31:168-173. [PMID: 39714396 DOI: 10.3201/eid3101.240401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2024] Open
Abstract
Using a prion amplification assay, we identified prions in tissues from wild pigs (Sus scrofa) living in areas of the United States with variable chronic wasting disease (CWD) epidemiology. Our findings indicate that scavenging swine could play a role in disseminating CWD and could therefore influence its epidemiology, geographic distribution, and interspecies spread.
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2
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Steadman BS, Bian J, Shikiya RA, Bartz JC. Minor prion substrains overcome transmission barriers. mBio 2024; 15:e0272124. [PMID: 39440977 PMCID: PMC11559082 DOI: 10.1128/mbio.02721-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Accepted: 09/26/2024] [Indexed: 10/25/2024] Open
Abstract
Mammalian prion diseases are infectious neurodegenerative diseases caused by the self-templating form of the prion protein PrPSc. Much evidence supports the hypothesis that prions exist as a mixture of a dominant strain and minor prion strains. While it is known that prions can infect new species, the relative contribution of the dominant prion strain and minor strains in crossing the species barrier is unknown. We previously identified minor prion strains from a biologically cloned drowsy (DY) strain of hamster-adapted transmissible mink encephalopathy (TME). Here we show that these minor prion strains have increased infection efficiency to rabbit kidney epithelial cells that express hamster PrPC compared to the dominant strain DY TME. Using protein misfolding cyclic amplification (PMCA), we found that the dominant strain DY TME failed to convert mouse PrPC to PrPSc, even after several serial passages. In contrast, the minor prion strains isolated from biologically cloned DY TME robustly converted mouse PrPC to PrPSc in the first round of PMCA. This observation indicates that minor prion strains from the mutant spectra contribute to crossing the species barrier. Additionally, we found that the PMCA conversion efficiency for the minor prion strains tested was significantly different from each other and from the short-incubation period prion strain HY TME. This suggests that minor strain diversity may be greater than previously anticipated. These observations further expand our understanding of the mechanisms underlying the species barrier effect and has implications for assessing the zoonotic potential of prions. IMPORTANCE Prions from cattle with bovine spongiform encephalopathy have transmitted to humans, whereas scrapie from sheep and goats likely has not, suggesting that some prions can cross species barriers more easily than others. Prions are composed of a dominant strain and minor strains, and the contribution of each population to adapt to new replicative environments is unknown. Recently, minor prion strains were isolated from the biologically cloned prion strain DY TME, and these minor prion strains differed in properties from the dominant prion strain, DY TME. Here we found that these minor prion strains also differed in conversion efficiency and host range compared to the dominant strain DY TME. These novel findings provide evidence that minor prion strains contribute to interspecies transmission, underscoring the significance of minor strain components in important biological processes.
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Affiliation(s)
- Benjamin S. Steadman
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska, USA
| | - Jifeng Bian
- Virus and Prion Research Unit, National Animal Disease Center, United States Department of Agriculture – Agricultural Research Services, Ames, Iowa, USA
| | - Ronald A. Shikiya
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska, USA
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska, USA
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3
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Liao X, Zhu W, Liao X, Liu W, Hou Y, Wan J. Expression of Toll-like receptors in the cerebellum during pathogenesis of prion disease. Front Behav Neurosci 2024; 18:1341901. [PMID: 38698886 PMCID: PMC11063360 DOI: 10.3389/fnbeh.2024.1341901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/19/2024] [Indexed: 05/05/2024] Open
Abstract
Prion diseases, such as scrapie, entail the accumulation of disease-specific prion protein (PrPSc) within the brain. Toll-like receptors (TLRs) are crucial components of the pattern recognition system. They recognize pathogen-associated molecular patterns (PAMPs) and play a central role in orchestrating host innate immune responses. The expression levels of Toll-like receptors (TLRs) in the central nervous system (CNS) were not well-defined. To establish a model of prion diseases in BALB/C mice, the 22L strain was employed. The features of the 22L strain were analyzed, and the cerebellum exhibited severe pathological changes. TLR1-13 levels in the cerebellum were measured using quantitative polymerase chain reaction (qPCR) at time points of 60, 90, 120, and the final end point (145 days post-infection). During the pathogenesis, the expression levels of Toll-like receptors (TLRs) 1, 2, 7, 8, and 9 increased in a time-dependent manner. This trend mirrored the expression patterns of PrPSc (the pathological isoform of the prion protein) and glial fibrillary acidic protein. Notably, at the end point, TLR1-13 levels were significantly elevated. Protein level of TLR7 and TLR9 showed increasing at the end point of the 22L-infected mice. A deeper understanding of the increased Toll-like receptors (TLRs) in prion diseases could shed light on their role in initiating immune responses at various stages during pathogenesis. This insight is particularly relevant when considering TLRs as potential therapeutic targets for prion diseases.
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Affiliation(s)
- Xiangyu Liao
- Department of Oncology, Yichang Central People's Hospital, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
| | - Wufei Zhu
- Department of Endocrinology, Yichang Central People's Hospital, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
| | - Xingyu Liao
- Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Wensen Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Yiwei Hou
- Department of Endocrinology, Yichang Central People's Hospital, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
| | - Jiayu Wan
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
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4
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Harpaz E, Vuong TT, Tran L, Tranulis MA, Benestad SL, Ersdal C. Inter- and intra-species conversion efficacies of Norwegian prion isolates estimated by serial protein misfolding cyclic amplification. Vet Res 2023; 54:84. [PMID: 37773068 PMCID: PMC10542671 DOI: 10.1186/s13567-023-01220-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/05/2023] [Indexed: 09/30/2023] Open
Abstract
Prion diseases, including chronic wasting disease (CWD) in cervids, are fatal neurodegenerative disorders caused by the misfolding of cellular prion proteins. CWD is known to spread among captive and free-ranging deer in North America. In 2016, an outbreak of contagious CWD was detected among wild reindeer in Norway, marking the first occurrence of the disease in Europe. Additionally, new sporadic forms of CWD have been discovered in red deer in Norway and moose in Fennoscandia. We used serial protein misfolding cyclic amplification to study the ability of Norwegian prion isolates from reindeer, red deer, and moose (two isolates), as well as experimental classical scrapie from sheep, to convert a panel of 16 brain homogenates (substrates) from six different species with various prion protein genotypes. The reindeer CWD isolate successfully converted substrates from all species except goats. The red deer isolate failed to convert sheep and goat substrates but exhibited amplification in all cervid substrates. The two moose isolates demonstrated lower conversion efficacies. The wild type isolate propagated in all moose substrates and in the wild type red deer substrate, while the other isolate only converted two of the moose substrates. The experimental classical scrapie isolate was successfully propagated in substrates from all species tested. Thus, reindeer CWD and classical sheep scrapie isolates were similarly propagated in substrates from different species, suggesting the potential for spillover of these contagious diseases. Furthermore, the roe deer substrate supported conversion of three isolates suggesting that this species may be vulnerable to prion disease.
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Affiliation(s)
- Erez Harpaz
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Svebastadveien 112, 4325, Sandnes, Norway
| | - Tram Thu Vuong
- Department of Biohazard and Pathology, Norwegian Veterinary Institute, P.O. box 64, 1431, Ås, Norway
| | - Linh Tran
- Department of Biohazard and Pathology, Norwegian Veterinary Institute, P.O. box 64, 1431, Ås, Norway
| | - Michael Andreas Tranulis
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Universitetstunet 3, 1433, Ås, Norway
| | - Sylvie L Benestad
- Department of Biohazard and Pathology, Norwegian Veterinary Institute, P.O. box 64, 1431, Ås, Norway
| | - Cecilie Ersdal
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Svebastadveien 112, 4325, Sandnes, Norway.
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5
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Jo WS, Kim YC, Oem JK, Jeong BH. First report of structural characteristics and polymorphisms of the prion protein gene in raccoon dogs: The possibility of prion disease-resistance. Front Vet Sci 2022; 9:989352. [PMID: 36204297 PMCID: PMC9530392 DOI: 10.3389/fvets.2022.989352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
Prion diseases are fatal degenerative encephalopathies caused by misfolded prion protein (PrPSc) converted from normal prion protein (PrPC). Previous studies have reported that genetic polymorphisms of the prion protein gene (PRNP) play a critical role in susceptibility to prion diseases. In addition, prion disease-resistant animals showed unique structural features of prion protein (PrP) related to species-specific amino acids. However, investigations of genetic polymorphisms of the PRNP gene and structural characteristics of PrP have not been performed in raccoon dogs thus far. We investigated genetic polymorphisms of PRNP in 87 raccoon dogs using amplicon sequencing and analyzed the genotype, allele, haplotype frequencies, and linkage disequilibrium (LD) using Haploview version 4.2. In addition, we performed phylogenetic analysis and multiple sequence alignment (MSA) using MEGA X version 10.1.8 and Clustal X version 2.1, respectively. We estimated the impact of raccoon dog and Canidae family-specific amino acids using PolyPhen-2, PROVEAN, and AMYCO. Furthermore, we analyzed the effect of raccoon dog and Canidae family-specific amino acids using the AlphaFold2 and Swiss-PdbViewer programs. We found 4 novel single nucleotide polymorphisms (SNPs) of the raccoon dog PRNP gene. In addition, the raccoon dog PrP showed 99.61% identity and the closest genetic distance to dog PrP. Among the substitutions of Canidae-specific amino acids with interspecific amino acids, D163N showed increased amyloidogenic propensity, and R181H showed alterations of hydrogen bonds. Furthermore, electrostatic potentials were changed according to the substitutions of D163N and R181H. By comparing PrP between raccoon dogs and raccoons, R168K and K224R were found to be related to changes in hydrogen bonds, and K224R altered the electrostatic potential of raccoon dog PrP. In the present study, we first reported 4 novel synonymous SNPs of the raccoon dog PRNP gene. We also identified that the PrP of raccoon dog has high homology (99.61%) with PrP of dog, which is a prion-resistant animal. In addition, raccoon dog PrP-specific amino acids are related to low amyloid propensity and inherent characteristics of 3D structure of raccoon dog PrP compared to the PrP of prion-susceptible species.
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Affiliation(s)
- Woo-Sung Jo
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, South Korea
- Department of Bioactive Material Sciences, Jeonbuk National University, Jeonju, South Korea
| | - Yong-Chan Kim
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, South Korea
- Department of Bioactive Material Sciences, Jeonbuk National University, Jeonju, South Korea
| | - Jae-Ku Oem
- Laboratory of Veterinary Infectious Diseases, College of Veterinary Medicine, Jeonbuk National University, Iksan, South Korea
| | - Byung-Hoon Jeong
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, South Korea
- Department of Bioactive Material Sciences, Jeonbuk National University, Jeonju, South Korea
- *Correspondence: Byung-Hoon Jeong
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Cassmann ED, Frese AJ, Moore SJ, Greenlee JJ. Transmission of Raccoon-Passaged Chronic Wasting Disease Agent to White-Tailed Deer. Viruses 2022; 14:v14071578. [PMID: 35891558 PMCID: PMC9320052 DOI: 10.3390/v14071578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/07/2022] [Accepted: 07/15/2022] [Indexed: 01/27/2023] Open
Abstract
The transmission characteristics of prion diseases are influenced by host prion protein sequence and, therefore, the host species. Chronic wasting disease (CWD), a prion disease of cervids, has widespread geographical distribution throughout North America and occurs in both wild and farmed populations. CWD prions contaminate the environment through scattered excrement and decomposing carcasses. Fresh carcasses with CWD prions are accessible by free-ranging mesopredators such as raccoons and may provide a route of exposure. Previous studies demonstrated the susceptibility of raccoons to CWD from white-tailed deer. In this study, we demonstrate that white-tailed deer replicate raccoon-passaged CWD prions which results in clinical disease similar to intraspecies CWD transmission. Six white-tailed deer were oronasally inoculated with brain homogenate from a raccoon with CWD. All six deer developed clinical disease, had widespread lymphoid distribution of misfolded CWD prions (PrPSc), and had neuropathologic lesions with PrPSc accumulation in the brain. The presence of PrPSc was confirmed by immunohistochemistry, enzyme-linked immunoassay, and western blot. The western blot migration pattern of raccoon-passaged CWD was different from white-tailed deer CWD. Transmission of raccoon CWD back to white-tailed deer resulted in an interposed molecular phenotype that was measurably different from white-tailed deer CWD.
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Affiliation(s)
- Eric D. Cassmann
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50010, USA; (E.D.C.); (A.J.F.); (S.J.M.)
| | - Alexis J. Frese
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50010, USA; (E.D.C.); (A.J.F.); (S.J.M.)
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd., Oak Ridge, TN 37830, USA
| | - S. Jo Moore
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50010, USA; (E.D.C.); (A.J.F.); (S.J.M.)
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd., Oak Ridge, TN 37830, USA
| | - Justin J. Greenlee
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50010, USA; (E.D.C.); (A.J.F.); (S.J.M.)
- Correspondence: ; Tel.: +1-515-337-7191
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7
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Transmission, Strain Diversity, and Zoonotic Potential of Chronic Wasting Disease. Viruses 2022; 14:v14071390. [PMID: 35891371 PMCID: PMC9316268 DOI: 10.3390/v14071390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/11/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023] Open
Abstract
Chronic wasting disease (CWD) is a prion disease affecting several species of captive and free-ranging cervids. In the past few decades, CWD has been spreading uncontrollably, mostly in North America, resulting in a high increase of CWD incidence but also a substantially higher number of geographical regions affected. The massive increase in CWD poses risks at several levels, including contamination of the environment, transmission to animals cohabiting with cervids, and more importantly, a putative transmission to humans. In this review, I will describe the mechanisms and routes responsible for the efficient transmission of CWD, the strain diversity of natural CWD, its spillover and zoonotic potential and strategies to minimize the CWD threat.
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8
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Susceptibility of Beavers to Chronic Wasting Disease. BIOLOGY 2022; 11:biology11050667. [PMID: 35625395 PMCID: PMC9137852 DOI: 10.3390/biology11050667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/16/2022] [Accepted: 04/20/2022] [Indexed: 11/17/2022]
Abstract
Chronic wasting disease (CWD) is a contagious, fatal, neurodegenerative prion disease of cervids. The expanding geographical range and rising prevalence of CWD are increasing the risk of pathogen transfer and spillover of CWD to non-cervid sympatric species. As beavers have close contact with environmental and food sources of CWD infectivity, we hypothesized that they may be susceptible to CWD prions. We evaluated the susceptibility of beavers to prion diseases by challenging transgenic mice expressing beaver prion protein (tgBeaver) with five strains of CWD, four isolates of rodent-adapted prions and one strain of Creutzfeldt-Jakob disease. All CWD strains transmitted to the tgBeaver mice, with attack rates highest from moose CWD and the 116AG and H95+ strains of deer CWD. Mouse-, rat-, and especially hamster-adapted prions were also transmitted with complete attack rates and short incubation periods. We conclude that the beaver prion protein is an excellent substrate for sustaining prion replication and that beavers are at risk for CWD pathogen transfer and spillover.
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Silva CJ. Chronic Wasting Disease (CWD) in Cervids and the Consequences of a Mutable Protein Conformation. ACS OMEGA 2022; 7:12474-12492. [PMID: 35465121 PMCID: PMC9022204 DOI: 10.1021/acsomega.2c00155] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/18/2022] [Indexed: 05/15/2023]
Abstract
Chronic wasting disease (CWD) is a prion disease of cervids (deer, elk, moose, etc.). It spreads readily from CWD-contaminated environments and among wild cervids. As of 2022, North American CWD has been found in 29 states, four Canadian provinces and South Korea. The Scandinavian form of CWD originated independently. Prions propagate their pathology by inducing a natively expressed prion protein (PrPC) to adopt the prion conformation (PrPSc). PrPC and PrPSc differ solely in their conformation. Like other prion diseases, transmissible CWD prions can arise spontaneously. The CWD prions can respond to selection pressures resulting in the emergence of new strain phenotypes. Annually, 11.5 million Americans hunt and harvest nearly 6 million deer, indicating that CWD is a potential threat to an important American food source. No tested CWD strain has been shown to be zoonotic. However, this may not be true for emerging strains. Should a zoonotic CWD strain emerge, it could adversely impact the hunting economy and game meat consumers.
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Affiliation(s)
- Christopher J. Silva
- Produce Safety & Microbiology
Research Unit, Western Regional Research Center, Agricultural Research
Service, United States Department of Agriculture, Albany, California 94710, United States of America
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10
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Moore SJ, Carlson CM, Schneider JR, Johnson CJ, Greenlee JJ. Increased Attack Rates and Decreased Incubation Periods in Raccoons with Chronic Wasting Disease Passaged through Meadow Voles. Emerg Infect Dis 2022; 28:793-801. [PMID: 35318913 PMCID: PMC8962881 DOI: 10.3201/eid2804.210271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chronic wasting disease (CWD) is a naturally-occurring neurodegenerative disease of cervids. Raccoons (Procyon lotor) and meadow voles (Microtus pennsylvanicus) have previously been shown to be susceptible to the CWD agent. To investigate the potential for transmission of the agent of CWD from white-tailed deer to voles and subsequently to raccoons, we intracranially inoculated raccoons with brain homogenate from a CWD-affected white-tailed deer (CWDWtd) or derivatives of this isolate after it had been passaged through voles 1 or 5 times. We found that passage of the CWDWtd isolate through voles led to a change in the biologic behavior of the CWD agent, including increased attack rates and decreased incubation periods in raccoons. A better understanding of the dynamics of cross-species transmission of CWD prions can provide insights into how these infectious proteins evolve in new hosts.
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Pritzkow S, Gorski D, Ramirez F, Soto C. Prion Dissemination through the Environment and Medical Practices: Facts and Risks for Human Health. Clin Microbiol Rev 2021; 34:e0005919. [PMID: 34319151 PMCID: PMC8404694 DOI: 10.1128/cmr.00059-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prion diseases are a group of fatal, infectious neurodegenerative disorders affecting various species of mammals, including humans. The infectious agent in these diseases, termed prion, is composed exclusively of a misfolded protein that can spread and multiply in the absence of genetic materials. In this article, we provide an overview of the mechanisms of prion replication, interindividual transmission, and dissemination in communities. In particular, we review the potential role of the natural environment in prion transmission, including the mechanisms and pathways for prion entry and accumulation in the environment as well as its roles in prion mutation, adaptation, evolution, and transmission. We also discuss the transmission of prion diseases through medical practices, scientific research, and use of biological products. Detailed knowledge of these aspects is crucial to limit the spreading of existing prion diseases as well as to prevent the emergence of new diseases with possible catastrophic consequences for public health.
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Affiliation(s)
- Sandra Pritzkow
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Damian Gorski
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Frank Ramirez
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Claudio Soto
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA
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Otero A, Velásquez CD, Aiken J, McKenzie D. Chronic wasting disease: a cervid prion infection looming to spillover. Vet Res 2021; 52:115. [PMID: 34488900 PMCID: PMC8420063 DOI: 10.1186/s13567-021-00986-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/29/2021] [Indexed: 11/10/2022] Open
Abstract
The spread of chronic wasting disease (CWD) during the last six decades has resulted in cervid populations of North America where CWD has become enzootic. This insidious disease has also been reported in wild and captive cervids from other continents, threatening ecosystems, livestock and public health. These CWD "hot zones" are particularly complex given the interplay between cervid PRNP genetics, the infection biology, the strain diversity of infectious prions and the long-term environmental persistence of infectivity, which hinder eradication efforts. Here, we review different aspects of CWD including transmission mechanisms, pathogenesis, epidemiology and assessment of interspecies infection. Further understanding of these aspects could help identify "control points" that could help reduce exposure for humans and livestock and decrease CWD spread between cervids.
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Affiliation(s)
- Alicia Otero
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, Universidad de Zaragoza, Zaragoza, Spain
| | - Camilo Duque Velásquez
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.,Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada. .,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.
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13
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Pritzkow S, Gorski D, Ramirez F, Telling GC, Benestad SL, Soto C. North American and Norwegian Chronic Wasting Disease prions exhibit different potential for interspecies transmission and zoonotic risk. J Infect Dis 2021; 225:542-551. [PMID: 34302479 DOI: 10.1093/infdis/jiab385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/23/2021] [Indexed: 12/17/2022] Open
Abstract
Chronic wasting disease (CWD) is a rapidly spreading prion disorder affecting various species of wild and captive cervids. The risk that CWD poses to co-habiting animals or more importantly to humans is largely unknown. In this study we investigated differences in the capacity of CWD isolates obtained from six different cervid species to induce prion conversion in vitro by PMCA. We define and quantify spillover and zoonotic potential indices as the efficiency by which CWD prions sustain prion generation in vitro at expenses of normal prion proteins from various mammals and human, respectively. Our data suggest that reindeer and red deer from Norway could be the most transmissible CWD prions to other mammals, whereas North American CWD prions were more prone to generate human prions in vitro. Our results suggest that Norway and North American CWD prions correspond to different strains with distinct spillover and zoonotic potentials.
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Affiliation(s)
- Sandra Pritzkow
- Mitchell Center for Alzheimer's disease and related Brain disorders, Department of Neurology, University of Texas McGovern Medical School at Houston, Texas, USA
| | - Damian Gorski
- Mitchell Center for Alzheimer's disease and related Brain disorders, Department of Neurology, University of Texas McGovern Medical School at Houston, Texas, USA
| | - Frank Ramirez
- Mitchell Center for Alzheimer's disease and related Brain disorders, Department of Neurology, University of Texas McGovern Medical School at Houston, Texas, USA
| | - Glenn C Telling
- Prion Research Center, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Sylvie L Benestad
- Norwegian Veterinary Institute, OIE Reference Laboratory for CWD, Oslo, Norway
| | - Claudio Soto
- Mitchell Center for Alzheimer's disease and related Brain disorders, Department of Neurology, University of Texas McGovern Medical School at Houston, Texas, USA
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14
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CHRONIC WASTING DISEASE MODELING: AN OVERVIEW. J Wildl Dis 2021; 56:741-758. [PMID: 32544029 DOI: 10.7589/2019-08-213] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/13/2019] [Indexed: 11/20/2022]
Abstract
Chronic wasting disease (CWD) is an infectious and fatal prion disease occurring in the family Cervidae. To update the research community regarding the status quo of CWD epidemic models, we conducted a meta-analysis on CWD research. We collected data from peer-reviewed articles published since 1980, when CWD was first diagnosed, until December 2018. We explored the analytical methods used historically to understand CWD. We used 14 standardized variables to assess overall analytical approaches of CWD research communities, data used, and the modeling methods used. We found that CWD modeling initiated in the early 2000s and has increased since then. Connectivity of the research community was heavily reliant on a cluster of CWD researchers. Studies focused primarily on regression and compartment-based models, population-level approaches, and host species of game management concern. Similarly, CWD research focused on single populations, species, and locations, neglecting modeling using community ecology and biogeographic approaches. Chronic wasting disease detection relied on classic diagnostic methods with limited sensitivity for most stages of infection. Overall, we found that past modeling efforts generated a solid baseline for understanding CWD in wildlife and increased our knowledge on infectious prion ecology. Future analytical efforts should consider more sensitive diagnostic methods to quantify uncertainty and broader scale studies to elucidate CWD transmission beyond population-level approaches. Considering that infectious prions may not follow biological rules of well-known wildlife pathogens (i.e., viruses, bacteria, fungi), assumptions used when modeling other infectious disease may not apply for CWD. Chronic wasting disease is a new challenge in wildlife epidemiology.
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Abstract
In sheep, scrapie is a fatal neurologic disease that is caused by a misfolded protein called a prion (designated PrPSc). The normal cellular prion protein (PrPC) is encoded by an endogenous gene, PRNP, that is present in high concentrations within the CNS. Although a broad range of functions has been described for PrPC, its entire range of functions has yet to be fully elucidated. Accumulation of PrPSc results in neurodegeneration. The PRNP gene has several naturally occurring polymorphisms, and there is a strong correlation between scrapie susceptibility and PRNP genotype. The cornerstone of scrapie eradication programs is the selection of scrapie-resistant genotypes to eliminate classical scrapie. Transmission of classical scrapie in sheep occurs during the prenatal and periparturient periods when lambs are highly susceptible. Initially, the scrapie agent is disseminated throughout the lymphoid system and into the CNS. Shedding of the scrapie agent occurs before the onset of clinical signs. In contrast to classical scrapie, atypical scrapie is believed to be a spontaneous disease that occurs in isolated instances in older animals within a flock. The agent that causes atypical scrapie is not considered to be naturally transmissible. Transmission of the scrapie agent to species other than sheep, including deer, has been experimentally demonstrated as has the transmission of nonscrapie prion agents to sheep. The purpose of this review is to outline the current methods for diagnosing scrapie in sheep and the techniques used for studying the pathogenesis and host range of the scrapie agent. Also discussed is the US scrapie eradication program including recent updates.
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Escobar LE, Pritzkow S, Winter SN, Grear DA, Kirchgessner MS, Dominguez-Villegas E, Machado G, Peterson AT, Soto C. The ecology of chronic wasting disease in wildlife. Biol Rev Camb Philos Soc 2020; 95:393-408. [PMID: 31750623 PMCID: PMC7085120 DOI: 10.1111/brv.12568] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 10/11/2019] [Accepted: 10/16/2019] [Indexed: 12/13/2022]
Abstract
Prions are misfolded infectious proteins responsible for a group of fatal neurodegenerative diseases termed transmissible spongiform encephalopathy or prion diseases. Chronic Wasting Disease (CWD) is the prion disease with the highest spillover potential, affecting at least seven Cervidae (deer) species. The zoonotic potential of CWD is inconclusive and cannot be ruled out. A risk of infection for other domestic and wildlife species is also plausible. Here, we review the current status of the knowledge with respect to CWD ecology in wildlife. Our current understanding of the geographic distribution of CWD lacks spatial and temporal detail, does not consider the biogeography of infectious diseases, and is largely biased by sampling based on hunters' cooperation and funding available for each region. Limitations of the methods used for data collection suggest that the extent and prevalence of CWD in wildlife is underestimated. If the zoonotic potential of CWD is confirmed in the short term, as suggested by recent results obtained in experimental animal models, there will be limited accurate epidemiological data to inform public health. Research gaps in CWD prion ecology include the need to identify specific biological characteristics of potential CWD reservoir species that better explain susceptibility to spillover, landscape and climate configurations that are suitable for CWD transmission, and the magnitude of sampling bias in our current understanding of CWD distribution and risk. Addressing these research gaps will help anticipate novel areas and species where CWD spillover is expected, which will inform control strategies. From an ecological perspective, control strategies could include assessing restoration of natural predators of CWD reservoirs, ultrasensitive CWD detection in biotic and abiotic reservoirs, and deer density and landscape modification to reduce CWD spread and prevalence.
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Affiliation(s)
- Luis E. Escobar
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, 24061, U.S.A
| | - Sandra Pritzkow
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, TX, 77030, U.S.A
| | - Steven N. Winter
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, 24061, U.S.A
| | - Daniel A. Grear
- US Geological Survey National Wildlife Health Center, Madison, WI, 59711, U.S.A
| | | | | | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, U.S.A
| | - A. Townsend Peterson
- Biodiversity Institute and Department of Ecology and Evolutionary Biology, The University of Kansas, Lawrence, KS, 66045, U.S.A
| | - Claudio Soto
- Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, TX, 77030, U.S.A
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Koutsoumanis K, Allende A, Alvarez-Ordoňez A, Bolton D, Bover-Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Skandamis P, Suffredini E, Andreoletti O, Benestad SL, Comoy E, Nonno R, da Silva Felicio T, Ortiz-Pelaez A, Simmons MM. Update on chronic wasting disease (CWD) III. EFSA J 2019; 17:e05863. [PMID: 32626163 PMCID: PMC7008890 DOI: 10.2903/j.efsa.2019.5863] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The European Commission asked EFSA for a Scientific Opinion: to revise the state of knowledge about the differences between the chronic wasting disease (CWD) strains found in North America (NA) and Europe and within Europe; to review new scientific evidence on the zoonotic potential of CWD and to provide recommendations to address the potential risks and to identify risk factors for the spread of CWD in the European Union. Full characterisation of European isolates is being pursued, whereas most NA CWD isolates have not been characterised in this way. The differing surveillance programmes in these continents result in biases in the types of cases that can be detected. Preliminary data support the contention that the CWD strains identified in Europe and NA are different and suggest the presence of strain diversity in European cervids. Current data do not allow any conclusion on the implications of strain diversity on transmissibility, pathogenesis or prevalence. Available data do not allow any conclusion on the zoonotic potential of NA or European CWD isolates. The risk of CWD to humans through consumption of meat cannot be directly assessed. At individual level, consumers of meat, meat products and offal derived from CWD-infected cervids will be exposed to the CWD agent(s). Measures to reduce human dietary exposure could be applied, but exclusion from the food chain of whole carcasses of infected animals would be required to eliminate exposure. Based on NA experiences, all the risk factors identified for the spread of CWD may be associated with animals accumulating infectivity in both the peripheral tissues and the central nervous system. A subset of risk factors is relevant for infected animals without involvement of peripheral tissues. All the risk factors should be taken into account due to the potential co-localisation of animals presenting with different disease phenotypes.
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