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Hoar BR, Ernest HB, Johnson LNL, LaCava MEF, Sandidge DJ, Gerow K, Mousel MR, Galloway NL, Swain W, Malmberg JL. Ecology and Chronic Wasting Disease Epidemiology Shape Prion Protein Gene Variation in Rocky Mountain Elk (Cervus elaphus nelsoni). J Wildl Dis 2024; 60:496-501. [PMID: 38287919 DOI: 10.7589/jwd-d-23-00062] [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] [Received: 04/05/2023] [Accepted: 12/06/2023] [Indexed: 01/31/2024]
Abstract
As chronic wasting disease (CWD) continues to spread across North America, the relationship between CWD and host genetics has become of interest. In Rocky Mountain elk (Cervus elaphus nelsoni), one or two copies of a leucine allele at codon 132 of the prion protein gene (132L*) has been shown to prolong the incubation period of CWD. Our study examined the relationship between CWD epidemiology and codon 132 evolution in elk from Wyoming, USA, from 2011 to 2018. Using PCR and Sanger sequencing, we genotyped 997 elk and assessed the relationship between genotype and CWD prevalence estimated from surveillance data. Using logistic regression, we showed that each 1% increase in CWD prevalence is associated with a 9.6% increase in the odds that an elk would have at least one copy of leucine at codon 132. In some regions, however, 132L* variants were found in the absence of CWD, indicating that evolutionary and epidemiologic patterns can be heterogeneous across space and time. We also provide evidence that naturally occurring CWD is not rare in 132L* elk, which merits the study of shedding kinetics in 132L* elk and the influence of genotype on CWD strain diversity. The management implications of cervid adaptations to CWD are difficult to predict. Studies that investigate the degree to which evolutionary outcomes are shaped by host spatial structure can provide useful epidemiologic insight, which can in turn aid management by informing scale and extent of mitigation actions.
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Affiliation(s)
| | | | - Laura N L Johnson
- Wyoming Game and Fish Department, 1212 South Adams Street, Laramie, Wyoming 82070, USA
| | - Melanie E F LaCava
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | | | - Ken Gerow
- Department of Mathematics and Statistics, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82071, USA
| | - Michelle R Mousel
- Animal Disease Research, Agricultural Research Service, US Department of Agriculture, 2020 Northeast Wilson Road, Pullman, Washington 99163, USA
- School for Global Health, Washington State University, 1155 Northeast College Avenue, Pullman, Washington 99164, USA
| | - Nathan L Galloway
- Biological Resources Division, National Park Service, 1201 Oakridge Drive #200, Fort Collins, Colorado 80525, USA
| | - William Swain
- One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, California 95616, USA
| | - Jennifer L Malmberg
- Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
- Current affiliation: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, US Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, Colorado 80521, USA
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Fameli AF, Edson J, Banfield JE, Rosenberry CS, Walter WD. Variability in prion protein genotypes by spatial unit to inform susceptibility to chronic wasting disease. Prion 2022; 16:254-264. [PMID: 36104983 PMCID: PMC9481152 DOI: 10.1080/19336896.2022.2117535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chronic wasting disease (CWD) is a fatal encephalopathy affecting North American cervids. Certain alleles in a host's prion protein gene are responsible for reduced susceptibility to CWD. We assessed for the first time variability in the prion protein gene of elk (Cervus canadensis) present in Pennsylvania, United States of America, a reintroduced population for which CWD cases have never been reported. We sequenced the prion protein gene (PRNP) of 565 elk samples collected over 7 years (2014-2020) and found two polymorphic sites (codon 21 and codon 132). The allele associated with reduced susceptibility to CWD is present in the population, and there was no evidence of deviations from Hardy-Weinberg equilibrium in any of our sampling years (p-values between 0.14 and 1), consistent with the lack of selective pressure on the PRNP. The less susceptible genotypes were found in a frequency similar to the ones reported for elk populations in the states of Wyoming and South Dakota before CWD was detected. We calculated the proportion of less susceptible genotypes in each hunt zone in Pennsylvania as a proxy for their vulnerability to the establishment of CWD, and interpolated these results to obtain a surface representing expected proportion of the less susceptible genotypes across the area. Based on this analysis, hunt zones located in the southern part of our study area have a low proportion of less susceptible genotypes, which is discouraging for elk persistence in Pennsylvania given that these hunt zones are adjacent to the deer Disease Management Area 3, where CWD has been present since 2014.
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Affiliation(s)
- Alberto F. Fameli
- Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, PA, USA,CONTACT Alberto F. Fameli Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, PA16802, USA
| | - Jessie Edson
- Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, PA, USA
| | - Jeremiah E. Banfield
- Pennsylvania Game Commission, Bureau of Wildlife Management, 2001 Elmerton Avenue,Harrisburg, PA, USA
| | - Christopher S. Rosenberry
- Pennsylvania Game Commission, Bureau of Wildlife Management, 2001 Elmerton Avenue,Harrisburg, PA, USA
| | - W. David Walter
- U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit, 403 Forest Resources Building, The Pennsylvania State University, University Park, PA, USA
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3
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Ketz AC, Robinson SJ, Johnson CJ, Samuel MD. Pathogen‐mediated selection and management implications for white‐tailed deer exposed to chronic wasting disease. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Alison C. Ketz
- Wisconsin Cooperative Research Unit Department of Forest and Wildlife Ecology University of Wisconsin Madison WI USA
| | - Stacie J. Robinson
- NOAA Hawaiian Monk Seal Research Program Pacific Islands Fisheries Science Center Honolulu HI USA
| | - Chad J. Johnson
- Medical Microbiology and Immunology University of Wisconsin Madison WI USA
| | - Michael D. Samuel
- Department of Forest and Wildlife Ecology University of Wisconsin Madison WI USA
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4
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Nichols TA, Nicholson EM, Liu Y, Tao W, Spraker TR, Lavelle M, Fischer J, Kong Q, VerCauteren KC. Detection of two dissimilar chronic wasting disease isolates in two captive Rocky Mountain elk ( Cervus canadensis) herds. Prion 2021; 15:207-215. [PMID: 34913829 PMCID: PMC8682864 DOI: 10.1080/19336896.2021.1982333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Chronic wasting disease (CWD) continues to spread in both wild and captive cervid herds in North America and has now been identified in wild reindeer and moose in Norway, Finland and Sweden. There is limited knowledge about the variety and characteristics of isolates or strains of CWD that exist in the landscape and their implications on wild and captive cervid herds. In this study, we evaluated brain samples from two captive elk herds that had differing prevalence, history and timelines of CWD incidence. Site 1 had a 16-year history of CWD with a consistently low prevalence between 5% and 10%. Twelve of fourteen naïve animals placed on the site remained CWD negative after 5 years of residence. Site 2 herd had a nearly 40-year known history of CWD with long-term environmental accrual of prion leading to nearly 100% of naïve animals developing clinical CWD within two to 12 years. Obex samples of several elk from each site were compared for CWD prion strain deposition, genotype in prion protein gene codon 132, and conformational stability of CWD prions. CWD prions in the obex from site 2 had a lower conformational stability than those from site 1, which was independent of prnp genotype at codon 132. These findings suggest the existence of different CWD isolates between the two sites and suggest potential differential disease attack rates for different CWD strains.
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Affiliation(s)
- Tracy A Nichols
- Veterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
| | - Eric M Nicholson
- Us Department of Agriculture, Agricultural Research Service, Ames, Iowa, USA
| | - Yihui Liu
- Departments of Pathology, Neurology, National Center for Regenerative Medicine, and National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Wanyun Tao
- Departments of Pathology, Neurology, National Center for Regenerative Medicine, and National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Terry R Spraker
- Prion Research Center and the Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, Colorado, USA
| | - Michael Lavelle
- Wildlife Services National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
| | - Justin Fischer
- Wildlife Services National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
| | - Qingzhong Kong
- Departments of Pathology, Neurology, National Center for Regenerative Medicine, and National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Kurt C VerCauteren
- Wildlife Services National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
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Galloway NL, Monello RJ, Brimeyer D, Cole EK, Hobbs NT. Supporting adaptive management with ecological forecasting: chronic wasting disease in the Jackson Elk Herd. Ecosphere 2021. [DOI: 10.1002/ecs2.3776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Nathan L. Galloway
- Biological Resources Division National Park Service Fort Collins Colorado USA
| | - Ryan J. Monello
- Pacific Island Inventory and Monitoring Network National Park Service Hawai'i Volcanoes National Park Hawaii USA
| | - Doug Brimeyer
- Wyoming Game and Fish Department Jackson Wyoming USA
| | - Eric K. Cole
- National Elk Refuge US Fish and Wildlife Service Jackson Wyoming USA
| | - N. Thompson Hobbs
- Department of Ecosystem Science and Sustainability Natural Resource Ecology Laboratory Colorado State University Fort Collins Colorado USA
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LaCava MEF, Malmberg JL, Edwards WH, Johnson LNL, Allen SE, Ernest HB. Spatio-temporal analyses reveal infectious disease-driven selection in a free-ranging ungulate. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210802. [PMID: 34430048 PMCID: PMC8355672 DOI: 10.1098/rsos.210802] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/06/2021] [Indexed: 05/07/2023]
Abstract
Infectious diseases play an important role in wildlife population dynamics by altering individual fitness, but detecting disease-driven natural selection in free-ranging populations is difficult due to complex disease-host relationships. Chronic wasting disease (CWD) is a fatal infectious prion disease in cervids for which mutations in a single gene have been mechanistically linked to disease outcomes, providing a rare opportunity to study disease-driven selection in wildlife. In Wyoming, USA, CWD has gradually spread across mule deer (Odocoileus hemionus) populations, producing natural variation in disease history to evaluate selection pressure. We used spatial variation and a novel temporal comparison to investigate the relationship between CWD and a mutation at codon 225 of the mule deer prion protein gene that slows disease progression. We found that individuals with the 'slow' 225F allele were less likely to test positive for CWD, and the 225F allele was more common in herds exposed to CWD longer. We also found that in the past 2 decades, the 225F allele frequency increased more in herds with higher CWD prevalence. This study expanded on previous research by analysing spatio-temporal patterns of individual and herd-based disease data to present multiple lines of evidence for disease-driven selection in free-ranging wildlife.
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Affiliation(s)
- Melanie E. F. LaCava
- Wildlife Genomics and Disease Ecology Laboratory, Department of Veterinary Sciences, Program in Ecology, University of Wyoming, Laramie, WY 82071, USA
| | - Jennifer L. Malmberg
- Department of Veterinary Sciences, Wyoming State Veterinary Laboratory, University of Wyoming, Laramie, WY 82070, USA
| | - William H. Edwards
- Wyoming Game and Fish Department, Wildlife Health Laboratory, Laramie, WY 82070, USA
| | - Laura N. L. Johnson
- Wildlife Genomics and Disease Ecology Laboratory, Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82071, USA
| | - Samantha E. Allen
- Wyoming Game and Fish Department, Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82070, USA
| | - Holly B. Ernest
- Wildlife Genomics and Disease Ecology Laboratory, Department of Veterinary Sciences, Program in Ecology, University of Wyoming, Laramie, WY 82071, USA
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7
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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: 2.0] [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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Maloney M, Merkle JA, Aadland D, Peck D, Horan RD, Monteith KL, Winslow T, Logan J, Finnoff D, Sims C, Schumaker B. Chronic wasting disease undermines efforts to control the spread of brucellosis in the Greater Yellowstone Ecosystem. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02129. [PMID: 32223053 DOI: 10.1002/eap.2129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/20/2019] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
Wildlife diseases pose a substantial threat to the provisioning of ecosystem services. We use a novel modeling approach to study the potential loss of these services through the imminent introduction of chronic wasting disease (CWD) to elk populations in the Greater Yellowstone Ecosystem (GYE). A specific concern is that concentrating elk at feedgrounds may exacerbate the spread of CWD, whereas eliminating feedgrounds may increase the number of elk on private ranchlands and the transmission of a second disease, brucellosis, from elk to cattle. To evaluate the consequences of management strategies given the threat of two concurrent wildlife diseases, we develop a spatiotemporal bioeconomic model. GPS data from elk and landscape attributes are used to predict migratory behavior and population densities with and without supplementary feeding. We use a 4,800 km2 area around Pinedale, Wyoming containing four existing feedgrounds as a case study. For this area, we simulate welfare estimates under a variety of management strategies. Our results indicate that continuing to feed elk could result in substantial welfare losses for the case-study region. Therefore, to maximize the present value of economic net benefits generated by the local elk population upon CWD's arrival in the region, wildlife managers may wish to consider discontinuing elk feedgrounds while simultaneously developing new methods to mitigate the financial impact to ranchers of possible brucellosis transmission to livestock. More generally, our methods can be used to weigh the costs and benefits of human-wildlife interactions in the presence of multiple disease risks.
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Affiliation(s)
- Matthew Maloney
- HS Strategy Department 01114, University of Utah Health Sciences, 102 S 200 E, Salt Lake City, Utah, 84109, USA
| | - Jerod A Merkle
- Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming, 82071, USA
| | - David Aadland
- Department of Economics, University of Wyoming, 1000 E. University Avenue, Laramie, Wyoming, 82072, USA
| | - Dannele Peck
- USDA Agricultural Research Service, 1701 Centre Avenue, Fort Collins, Colorado, 80526, USA
| | - Richard D Horan
- Department of Agricultural, Food, and Resource Economics, Justin S Morrill Hall of Agriculture, Michigan State University, 446 W. Circle Drive, Rm 303B, East Lansing, Michigan, 48824, USA
| | - Kevin L Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Bim Kendall House, 804 East Fremont Street, Laramie, Wyoming, 82072, USA
| | - Thach Winslow
- Wyoming Livestock Board, 1934 Wyott Drive, Cheyenne, Wyoming, 82002, USA
| | - Jim Logan
- Wyoming Livestock Board, 1934 Wyott Drive, Cheyenne, Wyoming, 82002, USA
| | - David Finnoff
- Department of Economics, University of Wyoming, 1000 E. University Avenue, Laramie, Wyoming, 82072, USA
| | - Charles Sims
- Howard H. Baker Jr. Center for Public Policy and Department of Economics, The University of Tennessee, 1640 Cumberland Avenue, Knoxville, Tennessee, 37996, USA
| | - Brant Schumaker
- Department of Veterinary Sciences, College of Agriculture & Natural Resources, University of Wyoming, 1174 Snowy Range Road, Laramie, Wyoming, 82070, USA
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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: 7.5] [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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Miller WL, Walter WD. Spatial heterogeneity of prion gene polymorphisms in an area recently infected by chronic wasting disease. Prion 2019; 13:65-76. [PMID: 30777498 PMCID: PMC7000142 DOI: 10.1080/19336896.2019.1583042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genetic variability in the prion protein (Prnp) gene influences host susceptibility to many pathogenic prion diseases. Understanding the distribution of susceptible Prnp variants and determining factors influencing spatial genetic patterns are important components of many chronic wasting disease mitigation strategies. Here, we describe Prnp variability in white-tailed deer (Odocoileus virginianus) from the Mid-Atlantic region of the United States of America, an area with a recent history of infection and low disease incidence. This population is characterized by lower rates of polymorphism and significantly higher frequencies of the more susceptible 96GG genotype compared to previously surveyed populations. The prevalence of the most susceptible genotypes at disease-associated loci did vary among subregions, indicating that populations have innate differences in genotype-dictated susceptibility.
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Affiliation(s)
- William L Miller
- a Pennsylvania Cooperative Fish and Wildlife Research Unit, Department of Ecosystem Science and Management, Intercollege Graduate Degree Program in Ecology , The Pennsylvania State University , University Park , PA , USA
| | - W David Walter
- b U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit , The Pennsylvania State University , University Park , PA , USA
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11
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Mysterud A, Edmunds DR. A review of chronic wasting disease in North America with implications for Europe. EUR J WILDLIFE RES 2019. [DOI: 10.1007/s10344-019-1260-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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12
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Wood ME, Griebel P, Huizenga ML, Lockwood S, Hansen C, Potter A, Cashman N, Mapletoft JW, Napper S. Accelerated onset of chronic wasting disease in elk (Cervus canadensis) vaccinated with a PrP Sc-specific vaccine and housed in a prion contaminated environment. Vaccine 2018; 36:7737-7743. [PMID: 30414779 DOI: 10.1016/j.vaccine.2018.10.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/07/2018] [Accepted: 10/14/2018] [Indexed: 10/27/2022]
Abstract
Chronic wasting disease (CWD) is a fatal prion disease affecting multiple cervid species. Effective management tools for this disease, particularly in free-ranging populations, are currently limited. We evaluated a novel CWD vaccine in elk (Cervus canadensis) naturally exposed to CWD through a prion-contaminated environment. The vaccine targets a YYR disease-specific epitope to induce antibody responses specific to the misfolded (PrPSc) conformation. Female elk calves (n = 41) were captured from western Wyoming and transported to the Thorne-Williams Wildlife Research Center where CWD has been documented since 1979. Elk were held in contaminated pens for 14 to 20 days before being alternately assigned to either a vaccine (n = 21) or control group (n = 20). Vaccinated animals initially received two vaccinations approximately 42 days apart and annual vaccinations thereafter. Vaccination induced elevated YYR-specific antibody titers in all animals. Elk were genotyped for the prion protein gene at codon 132, monitored for clinical signs of CWD through daily observation, for disease status through periodic biopsy of rrectoanal mucosa-associated lympoid tissue (RAMALT), and monitored for YYR-specific serum antibody titres. Mean survival of vaccinated elk with the 132MM genotype (n = 15) was significantly shorter (800 days) than unvaccinated elk (n = 13) of the same genotype (1062 days; p = 0.003). Mean days until positive RAMALT biopsy for 132MM vaccinated elk (6 7 8) were significantly shorter than unvaccinated 132MM elk (990; p = 0.012). There was, however, no significant difference in survival between vaccinated (n = 4) and control (n = 5) elk with the 132ML genotype (p = 0.35) or in timing of positive RAMALT biopsies of 132ML elk (p = 0.66). There was no strong (p = 0.17) correlation between YYR-specific antibody titers and survival time. Determining the mechanism by which this vaccine accelerates onset of CWD will be important to direct further CWD vaccine research.
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Affiliation(s)
- Mary E Wood
- Wyoming Game and Fish Department, 1212 South Adams St, Laramie, WY, USA; Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA.
| | - Philip Griebel
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada; School of Public Health, University of Saskatchewan, 104 Clinic Place, S7N 2Z4 Saskatoon, Saskatchewan, Canada
| | - Matthew L Huizenga
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Samuel Lockwood
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Cole Hansen
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Andrew Potter
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada
| | - Neil Cashman
- Department of Neurology, University of British Columbia, S192 - 2211 Wesbrook Mall, V6T 2B5 Vancouver, BC, Canada
| | - John W Mapletoft
- Pan-Provincial Vaccine Enterprise Inc. University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada
| | - Scott Napper
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada; Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, S7N 5E5 Saskatoon, Saskatchewan, Canada
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13
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Cotterill GG, Cross PC, Middleton AD, Rogerson JD, Scurlock BM, du Toit JT. Hidden cost of disease in a free-ranging ungulate: brucellosis reduces mid-winter pregnancy in elk. Ecol Evol 2018; 8:10733-10742. [PMID: 30519402 PMCID: PMC6262735 DOI: 10.1002/ece3.4521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/06/2018] [Accepted: 08/19/2018] [Indexed: 11/08/2022] Open
Abstract
Demonstrating disease impacts on the vital rates of free-ranging mammalian hosts typically requires intensive, long-term study. Evidence for chronic pathogens affecting reproduction but not survival is rare, but has the potential for wide-ranging effects. Accurately quantifying disease-associated reductions in fecundity is important for advancing theory, generating accurate predictive models, and achieving effective management. We investigated the impacts of brucellosis (Brucella abortus) on elk (Cervus canadensis) productivity using serological data from over 6,000 captures since 1990 in the Greater Yellowstone Ecosystem, USA. Over 1,000 of these records included known age and pregnancy status. Using Bayesian multilevel models, we estimated the age-specific pregnancy probabilities of exposed and naïve elk. We then used repeat-capture data to investigate the full effects of the disease on life history. Brucellosis exposure reduced pregnancy rates of elk captured in mid- and late-winter. In an average year, we found 60% of exposed 2-year-old elk were pregnant compared to 91% of their naïve counterparts (a 31 percentage point reduction, 89% HPDI = 20%-42%), whereas exposed 3- to 9-year-olds were 7 percentage points less likely to be pregnant than naïve elk of their same age (89% HPDI = 2%-11%). We found these reduced rates of pregnancy to be independent from disease-induced abortions, which afflict a portion of exposed elk. We estimate that the combination of reduced pregnancy by mid-winter and the abortions following mid-winter reduces the reproductive output of exposed female elk by 24%, which affects population dynamics to a similar extent as severe winters or droughts. Exposing hidden reproductive costs of disease is essential to avoid conflating them with the effects of climate and predation. Such reproductive costs cause complex population dynamics, and the magnitude of the effect we found should drive a strong selection gradient if there is heritable resistance.
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Affiliation(s)
| | - Paul C. Cross
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterBozemanMontana
| | - Arthur D. Middleton
- Department of Environmental Science, Policy and ManagementUniversity of CaliforniaBerkeleyCalifornia
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Pathogen-mediated selection in free-ranging elk populations infected by chronic wasting disease. Proc Natl Acad Sci U S A 2017; 114:12208-12212. [PMID: 29087314 DOI: 10.1073/pnas.1707807114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pathogens can exert a large influence on the evolution of hosts via selection for alleles or genotypes that moderate pathogen virulence. Inconsistent interactions between parasites and the host genome, such as those resulting from genetic linkages and environmental stochasticity, have largely prevented observation of this process in wildlife species. We examined the prion protein gene (PRNP) in North American elk (Cervus elaphus nelsoni) populations that have been infected with chronic wasting disease (CWD), a contagious, fatal prion disease, and compared allele frequency to populations with no history of exposure to CWD. The PRNP in elk is highly conserved and a single polymorphism at codon 132 can markedly extend CWD latency when the minor leucine allele (132L) is present. We determined population exposure to CWD, genotyped 1,018 elk from five populations, and developed a hierarchical Bayesian model to examine the relationship between CWD prevalence and PRNP 132L allele frequency. Populations infected with CWD for at least 30-50 y exhibited 132L allele frequencies that were on average twice as great (range = 0.23-0.29) as those from uninfected populations (range = 0.04-0.17). Despite numerous differences between the elk populations in this study, the consistency of increase in 132L allele frequency suggests pathogen-mediated selection has occurred due to CWD. Although prior modeling work predicted that selection will continue, the potential for fitness costs of the 132L allele or new prion protein strains to arise suggest that it is prudent to assume balancing selection may prevent fixation of the 132L allele in populations with CWD.
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DeVivo MT, Edmunds DR, Kauffman MJ, Schumaker BA, Binfet J, Kreeger TJ, Richards BJ, Schätzl HM, Cornish TE. Endemic chronic wasting disease causes mule deer population decline in Wyoming. PLoS One 2017; 12:e0186512. [PMID: 29049389 PMCID: PMC5648191 DOI: 10.1371/journal.pone.0186512] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/03/2017] [Indexed: 11/19/2022] Open
Abstract
Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), Rocky Mountain elk (Cervus elaphus nelsoni), and moose (Alces alces shirasi) in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate (λ). Mule deer were captured from 2010-2014 in southern Converse County Wyoming, USA. Captured adult (≥ 1.5 years old) deer were tested ante-mortem for CWD using tonsil biopsies and monitored using radio telemetry. Mean annual survival rates of CWD-negative and CWD-positive deer were 0.76 and 0.32, respectively. Pregnancy and fawn recruitment were not observed to be influenced by CWD. We estimated λ = 0.79, indicating an annual population decline of 21% under current CWD prevalence levels. A model derived from the demography of only CWD-negative individuals yielded; λ = 1.00, indicating a stable population if CWD were absent. These findings support CWD as a significant contributor to mule deer population decline. Chronic wasting disease is difficult or impossible to eradicate with current tools, given significant environmental contamination, and at present our best recommendation for control of this disease is to minimize spread to new areas and naïve cervid populations.
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Affiliation(s)
- Melia T. DeVivo
- Department of Veterinary Sciences, University of Wyoming, Laramie, Wyoming, United States of America
- * E-mail:
| | - David R. Edmunds
- Natural Resource Ecology Laboratory, Colorado State University/US Geological Survey, Fort Collins, Colorado, United States of America
| | - Matthew J. Kauffman
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Brant A. Schumaker
- Department of Veterinary Sciences, University of Wyoming, Laramie, Wyoming, United States of America
| | - Justin Binfet
- Wyoming Game and Fish Department, Casper, Wyoming, United States of America
| | - Terry J. Kreeger
- Wyoming Game and Fish Department, Wheatland, Wyoming, United States of America
| | - Bryan J. Richards
- U.S. Geological Survey, National Wildlife Health Center, Madison, Wisconsin, United States of America
| | - Hermann M. Schätzl
- Department of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Todd E. Cornish
- Department of Veterinary Sciences, University of Wyoming, Laramie, Wyoming, United States of America
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16
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Plummer IH, Wright SD, Johnson CJ, Pedersen JA, Samuel MD. Temporal patterns of chronic wasting disease prion excretion in three cervid species. J Gen Virol 2017; 98:1932-1942. [PMID: 28708047 DOI: 10.1099/jgv.0.000845] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chronic wasting disease (CWD) is the only naturally occurring transmissible spongiform encephalopathy affecting free-ranging wildlife populations. Transmission of CWD occurs by direct contact or through contaminated environments; however, little is known about the temporal patterns of CWD prion excretion and shedding in wild cervids. We tested the urine and faeces of three species of captive cervids (elk, mule and white-tailed deer) at 6, 12, 18 and 24 months after oral inoculation to evaluate the temporal, species- and genotype-specific factors affecting the excretion of CWD prions. Although none of the animals exhibited clinical signs of CWD during the study, we determined that all three cervid species were excreting CWD prions by 6 months post-inoculation. Faecal samples were consistently positive for CWD prions for all three cervid species (88 %), and were more likely to be positive than urine samples (28 %). Cervids with genotypes encoding for the prion protein (PRNP) that were considered to be more susceptible to CWD were more likely to excrete CWD prions (94 %) than cervids with genotypes considered to be less susceptible (64 %). All cervids with CWD prions in their urine also had positive faeces (n=5), but the converse was not true. Our study is the first to demonstrate CWD prion excretion in urine by asymptomatic elk and mule deer. Our results indicate that the excretion of CWD prions in faeces and, to a lesser extent, urine may provide an important avenue for depositing prions in the environment.
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Affiliation(s)
- Ian H Plummer
- Department of Forest and Wildlife Ecology, University of Wisconsin - Madison, 1630 Linden Drive, Madison, WI 53706, USA
| | - Scott D Wright
- US Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison, Wisconsin 53711, USA.,Present address: 4730 Toepfer Road, Middleton, Wisconsin 53562, USA
| | - Chad J Johnson
- Departments of Soil Science, Civil and Environmental Engineering, and Chemistry, University of Wisconsin - Madison, 1525 Observatory Drive, Madison, Wisconsin 53706, USA
| | - Joel A Pedersen
- Departments of Soil Science, Civil and Environmental Engineering, and Chemistry, University of Wisconsin - Madison, 1525 Observatory Drive, Madison, Wisconsin 53706, USA
| | - Michael D Samuel
- Retired, US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin - Madison, 204 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA
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Chronic Wasting Disease Drives Population Decline of White-Tailed Deer. PLoS One 2016; 11:e0161127. [PMID: 27575545 PMCID: PMC5004924 DOI: 10.1371/journal.pone.0161127] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/30/2016] [Indexed: 11/19/2022] Open
Abstract
Chronic wasting disease (CWD) is an invariably fatal transmissible spongiform encephalopathy of white-tailed deer, mule deer, elk, and moose. Despite a 100% fatality rate, areas of high prevalence, and increasingly expanding geographic endemic areas, little is known about the population-level effects of CWD in deer. To investigate these effects, we tested the null hypothesis that high prevalence CWD did not negatively impact white-tailed deer population sustainability. The specific objectives of the study were to monitor CWD-positive and CWD-negative white-tailed deer in a high-prevalence CWD area longitudinally via radio-telemetry and global positioning system (GPS) collars. For the two populations, we determined the following: a) demographic and disease indices, b) annual survival, and c) finite rate of population growth (λ). The CWD prevalence was higher in females (42%) than males (28.8%) and hunter harvest and clinical CWD were the most frequent causes of mortality, with CWD-positive deer over-represented in harvest and total mortalities. Survival was significantly lower for CWD-positive deer and separately by sex; CWD-positive deer were 4.5 times more likely to die annually than CWD-negative deer while bucks were 1.7 times more likely to die than does. Population λ was 0.896 (0.859–0.980), which indicated a 10.4% annual decline. We show that a chronic disease that becomes endemic in wildlife populations has the potential to be population-limiting and the strong population-level effects of CWD suggest affected populations are not sustainable at high disease prevalence under current harvest levels.
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Potapov A, Merrill E, Pybus M, Lewis MA. Chronic Wasting Disease: Transmission Mechanisms and the Possibility of Harvest Management. PLoS One 2016; 11:e0151039. [PMID: 26963921 PMCID: PMC4786122 DOI: 10.1371/journal.pone.0151039] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 02/23/2016] [Indexed: 01/30/2023] Open
Abstract
We develop a model of CWD management by nonselective deer harvest, currently the most feasible approach available for managing CWD in wild populations. We use the model to explore the effects of 6 common harvest strategies on disease prevalence and to identify potential optimal harvest policies for reducing disease prevalence without population collapse. The model includes 4 deer categories (juveniles, adult females, younger adult males, older adult males) that may be harvested at different rates, a food-based carrying capacity, which influences juvenile survival but not adult reproduction or survival, and seasonal force of infection terms for each deer category under differing frequency-dependent transmission dynamics resulting from environmental and direct contact mechanisms. Numerical experiments show that the interval of transmission coefficients β where the disease can be controlled is generally narrow and efficiency of a harvest policy to reduce disease prevalence depends crucially on the details of the disease transmission mechanism, in particular on the intensity of disease transmission to juveniles and the potential differences in the behavior of older and younger males that influence contact rates. Optimal harvest policy to minimize disease prevalence for each of the assumed transmission mechanisms is shown to depend on harvest intensity. Across mechanisms, a harvest that focuses on antlered deer, without distinguishing between age classes reduces disease prevalence most consistently, whereas distinguishing between young and older antlered deer produces higher uncertainty in the harvest effects on disease prevalence. Our results show that, despite uncertainties, a modelling approach can determine classes of harvest strategy that are most likely to be effective in combatting CWD.
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Affiliation(s)
- Alex Potapov
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Centre for Mathematical Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
| | - Evelyn Merrill
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Margo Pybus
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Alberta Sustainable Resource Development, Edmonton, Alberta, Canada
| | - Mark A. Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Centre for Mathematical Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada
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Wickner RB, Kelly AC. Prions are affected by evolution at two levels. Cell Mol Life Sci 2016; 73:1131-44. [PMID: 26713322 PMCID: PMC4762734 DOI: 10.1007/s00018-015-2109-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
Abstract
Prions, infectious proteins, can transmit diseases or be the basis of heritable traits (or both), mostly based on amyloid forms of the prion protein. A single protein sequence can be the basis for many prion strains/variants, with different biological properties based on different amyloid conformations, each rather stably propagating. Prions are unique in that evolution and selection work at both the level of the chromosomal gene encoding the protein, and on the prion itself selecting prion variants. Here, we summarize what is known about the evolution of prion proteins, both the genes and the prions themselves. We contrast the one known functional prion, [Het-s] of Podospora anserina, with the known disease prions, the yeast prions [PSI+] and [URE3] and the transmissible spongiform encephalopathies of mammals.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8, Room 225, 8 Center Drive MSC 0830, Bethesda, MD, 20892-0830, USA.
| | - Amy C Kelly
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8, Room 225, 8 Center Drive MSC 0830, Bethesda, MD, 20892-0830, USA.
- NCAUR, Agricultural Research Service, U.S. Department of Agriculture, 1815 N. University St., Peoria, IL, 61604, USA.
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