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Cook M, Hensley-McBain T, Grindeland A. Mouse models of chronic wasting disease: A review. FRONTIERS IN VIROLOGY 2023. [DOI: 10.3389/fviro.2023.1055487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Animal models are essential tools for investigating and understanding complex prion diseases like chronic wasting disease (CWD), an infectious prion disease of cervids (elk, deer, moose, and reindeer). Over the past several decades, numerous mouse models have been generated to aid in the advancement of CWD knowledge and comprehension. These models have facilitated the investigation of pathogenesis, transmission, and potential therapies for CWD. Findings have impacted CWD management and disease outcomes, though much remains unknown, and a cure has yet to be discovered. Studying wildlife for CWD effects is singularly difficult due to the long incubation time, subtle clinical signs at early stages, lack of convenient in-the-field live testing methods, and lack of reproducibility of a controlled laboratory setting. Mouse models in many cases is the first step to understanding the mechanisms of disease in a shortened time frame. Here, we provide a comprehensive review of studies with mouse models in CWD research. We begin by reviewing studies that examined the use of mouse models for bioassays for tissues, bodily fluids, and excreta that spread disease, then address routes of infectivity and infectious load. Next, we delve into studies of genetic factors that influence protein structure. We then move on to immune factors, possible transmission through environmental contamination, and species barriers and differing prion strains. We conclude with studies that make use of cervidized mouse models in the search for therapies for CWD.
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Suminda GGD, Bhandari S, Won Y, Goutam U, Kanth Pulicherla K, Son YO, Ghosh M. High-throughput sequencing technologies in the detection of livestock pathogens, diagnosis, and zoonotic surveillance. Comput Struct Biotechnol J 2022; 20:5378-5392. [PMID: 36212529 PMCID: PMC9526013 DOI: 10.1016/j.csbj.2022.09.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 12/03/2022] Open
Abstract
Increasing globalization, agricultural intensification, urbanization, and climatic changes have resulted in a significant recent increase in emerging infectious zoonotic diseases. Zoonotic diseases are becoming more common, so innovative, effective, and integrative research is required to better understand their transmission, ecological implications, and dynamics at wildlife-human interfaces. High-throughput sequencing (HTS) methodologies have enormous potential for unraveling these contingencies and improving our understanding, but they are only now beginning to be realized in livestock research. This study investigates the current state of use of sequencing technologies in the detection of livestock pathogens such as bovine, dogs (Canis lupus familiaris), sheep (Ovis aries), pigs (Sus scrofa), horses (Equus caballus), chicken (Gallus gallus domesticus), and ducks (Anatidae) as well as how it can improve the monitoring and detection of zoonotic infections. We also described several high-throughput sequencing approaches for improved detection of known, unknown, and emerging infectious agents, resulting in better infectious disease diagnosis, as well as surveillance of zoonotic infectious diseases. In the coming years, the continued advancement of sequencing technologies will improve livestock research and hasten the development of various new genomic and technological studies on farm animals.
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Luers L, Bannach O, Stöhr J, Wördehoff MM, Wolff M, Nagel-Steger L, Riesner D, Willbold D, Birkmann E. Seeded fibrillation as molecular basis of the species barrier in human prion diseases. PLoS One 2013; 8:e72623. [PMID: 23977331 PMCID: PMC3748051 DOI: 10.1371/journal.pone.0072623] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 07/11/2013] [Indexed: 12/04/2022] Open
Abstract
Prion diseases are transmissible spongiform encephalopathies in humans and animals, including scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in deer, and Creutzfeldt-Jakob disease (CJD) in humans. The hallmark of prion diseases is the conversion of the host-encoded prion protein (PrPC) to its pathological isoform PrPSc, which is accompanied by PrP fibrillation. Transmission is not restricted within one species, but can also occur between species. In some cases a species barrier can be observed that results in limited or unsuccessful transmission. The mechanism behind interspecies transmissibility or species barriers is not completely understood. To analyse this process at a molecular level, we previously established an in vitro fibrillation assay, in which recombinant PrP (recPrP) as substrate can be specifically seeded by PrPSc as seed. Seeding with purified components, with no additional cellular components, is a direct consequence of the “prion-protein-only” hypothesis. We therefore hypothesise, that the species barrier is based on the interaction of PrPC and PrPSc. Whereas in our earlier studies, the interspecies transmission in animal systems was analysed, the focus of this study lies on the transmission from animals to humans. We therefore combined seeds from species cattle, sheep and deer (BSE, scrapie, CWD) with human recPrP. Homologous seeding served as a control. Our results are consistent with epidemiology, other in vitro aggregation studies, and bioassays investigating the transmission between humans, cattle, sheep, and deer. In contrast to CJD and BSE seeds, which show a seeding activity we can demonstrate a species barrier for seeds from scrapie and CWD in vitro. We could show that the seeding activity and therewith the molecular interaction of PrP as substrate and PrPSc as seed is sufficient to explain the phenomenon of species barriers. Therefore our data supports the hypothesis that CWD is not transmissible to humans.
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Affiliation(s)
- Lars Luers
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
| | - Oliver Bannach
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California, United States of America
| | | | - Martin Wolff
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
- Institute of Complex Systems (ICS-6), Research Centre Juelich, Juelich, Germany
| | - Luitgard Nagel-Steger
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
- Institute of Complex Systems (ICS-6), Research Centre Juelich, Juelich, Germany
| | - Detlev Riesner
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
| | - Dieter Willbold
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
- Institute of Complex Systems (ICS-6), Research Centre Juelich, Juelich, Germany
| | - Eva Birkmann
- Institute of Physical Biology, Heinrich-Heine University, Düsseldorf, Germany
- Institute of Complex Systems (ICS-6), Research Centre Juelich, Juelich, Germany
- * E-mail:
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Prion protein polymorphisms and estimation of risk of scrapie in East Asian sheep. Biochem Genet 2010; 48:13-25. [PMID: 19731007 DOI: 10.1007/s10528-009-9287-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 05/28/2009] [Indexed: 10/20/2022]
Abstract
Allele and genotype frequency distributions of prion protein (PrP) polymorphisms at three codons, 136, 154, and 171, in East Asian sheep were determined by PCR-RFLP analysis using 553 animals from nine local breeds of the northern group and four local breeds of the southern group. Based on the genotype distribution, the risk score for scrapie was estimated. Among the local breeds, ARQ appeared predominantly (0.7701-1), followed by ARH and ARR. From such a biased allele distribution, it was difficult to ascertain the prevalent genetic relationships. A marked difference in allele frequencies between the northern and southern groups was seen (P < 0.0001). The East Asian sheep had ARQ at the highest frequency (0.8834); in European sheep it was 0.5317. According to an assessment of scrapie risk in the PrP genotype classes, the predominant ARQ/ARQ in East Asian sheep corresponded to the risk score of R4. This finding suggests that East Asian sheep have a high level of genetic susceptibility to scrapie.
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Ryder SJ, Dexter GE, Heasman L, Warner R, Moore SJ. Accumulation and dissemination of prion protein in experimental sheep scrapie in the natural host. BMC Vet Res 2009; 5:9. [PMID: 19243608 PMCID: PMC2649917 DOI: 10.1186/1746-6148-5-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 02/25/2009] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND In order to study the sites of uptake and mechanisms of dissemination of scrapie prions in the natural host under controlled conditions, lambs aged 14 days and homozygous for the VRQ allele of the PrP gene were infected by the oral route. Infection occurred in all lambs with a remarkably short and highly consistent incubation period of approximately 6 months. Challenge of lambs at approximately eight months of age resulted in disease in all animals, but with more variable incubation periods averaging significantly longer than those challenged at 14 days. This model provides an excellent system in which to study the disease in the natural host by virtue of the relatively short incubation period and close resemblance to natural infection. RESULTS Multiple sites of prion uptake were identified, of which the most important was the Peyer's patch of the distal ileum. Neuroinvasion was detected initially in the enteric nervous system prior to infection of the central nervous system. At end stage disease prion accumulation was widespread throughout the entire neuraxis, but vacuolar pathology was absent in most animals that developed disease at 6-7 months of age. CONCLUSION Initial spread of detectable PrP was consistent with drainage in afferent lymph to dependent lymph nodes. Subsequent accumulation of prions in lymphoid tissue not associated with the gut is consistent with haematogenous spread. In addition to macrophages and follicular dendritic cells, prion containing cells consistent with afferent lymph dendritic cells were identified and are suggested as a likely vehicle for carriage of prions from initial site of uptake to the lymphoreticular system, and as potential carriers of prion protein in blood. It is apparent that spongiform change, the characteristic lesion of scrapie and other prion diseases, is not responsible for the clinical signs in sheep, but may develop in an age dependent manner.
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Affiliation(s)
- Stephen J Ryder
- Department of Pathology, Veterinary Laboratories Agency, Woodham Lane, New Haw, Addlestone, Surrey KT153NB, UK.
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Crossing the species barrier by PrP(Sc) replication in vitro generates unique infectious prions. Cell 2008; 134:757-68. [PMID: 18775309 DOI: 10.1016/j.cell.2008.07.030] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 05/08/2008] [Accepted: 07/21/2008] [Indexed: 11/24/2022]
Abstract
Prions are unconventional infectious agents composed exclusively of misfolded prion protein (PrP(Sc)), which transmits the disease by propagating its abnormal conformation to the cellular prion protein (PrP(C)). A key characteristic of prions is their species barrier, by which prions from one species can only infect a limited number of other species. Here, we report the generation of infectious prions by interspecies transmission of PrP(Sc) misfolding by in vitro PMCA amplification. Hamster PrP(C) misfolded by mixing with mouse PrP(Sc) generated unique prions that were infectious to wild-type hamsters, and similar results were obtained in the opposite direction. Successive rounds of PMCA amplification result in adaptation of the in vitro-produced prions, in a process reminiscent of strain stabilization observed upon serial passage in vivo. Our results indicate that PMCA is a valuable tool for the investigation of cross-species transmission and suggest that species barrier and strain generation are determined by the propagation of PrP misfolding.
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Consumption of beef tongue: Human BSE risk associated with exposure to lymphoid tissue in bovine tongue in consideration of new research findings - Scientific Opinion of the Panel on Biological Hazards. EFSA J 2008. [DOI: 10.2903/j.efsa.2008.700] [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
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Hagenaars TJ, Donnelly CA, Ferguson NM. Epidemiological analysis of data for scrapie in Great Britain. Epidemiol Infect 2006; 134:359-67. [PMID: 16490141 PMCID: PMC2870388 DOI: 10.1017/s0950268805004966] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2005] [Indexed: 11/06/2022] Open
Abstract
In recent years, the control or eradication of scrapie and any other transmissible spongiform encephalopathies (TSEs) possibly circulating in the sheep population has become a priority in Britain and elsewhere in Europe. A better understanding of the epidemiology of scrapie would greatly aid the development and evaluation of control and eradication strategies. Here we bound the range of key epidemiological parameters using a combination of relatively detailed pathogenesis and demography data, more limited data on susceptibility and incubation times, and recent survey data on scrapie incidence in Great Britain. These data are simultaneously analysed using mathematical models describing scrapie transmission between sheep and between flocks. Our analysis suggests that occurrence of scrapie in a flock typically provokes changes in flock management that promote termination of the outbreak, such as the adoption of selective breeding, and that a large fraction of cases (possibly over 80%) goes undetected. We show that the data analysed are consistent with the within-flock reproduction number of scrapie lying in the range 1.5-6, consistent with previous epidemiological studies.
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Affiliation(s)
- T J Hagenaars
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London, UK.
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Garcia-Crespo D, Juste RA, Hurtado A. Selection of ovine housekeeping genes for normalisation by real-time RT-PCR; analysis of PrP gene expression and genetic susceptibility to scrapie. BMC Vet Res 2005; 1:3. [PMID: 16188044 PMCID: PMC1262732 DOI: 10.1186/1746-6148-1-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 09/28/2005] [Indexed: 11/23/2022] Open
Abstract
Background Cellular prion protein expression is essential for the development of transmissible spongiform encephalopathies (TSEs), and in sheep, genetic susceptibility to scrapie has been associated to PrP gene polymorphisms. To test the hypothetical linkage between PrP gene expression and genetic susceptibility, PrP mRNA levels were measured by real-time RT-PCR in six ovine tissues of animals with different genotypes. Results Previous to the PrP gene expression analysis the stability of several housekeeping (HK) genes was assessed in order to select the best ones for relative quantification. The normalisation of gene expression was carried out using a minimum of three HK genes in order to detect small expression differences more accurately than using a single control gene. The expression stability analysis of six HK genes showed a large tissue-associated variation reflecting the existence of tissue-specific factors. Thereby, a specific set of HK genes was required for an accurate normalisation of the PrP gene expression within each tissue. Statistical differences in the normalised PrP mRNA levels were found among the tissues, obtaining the highest expression level in obex, followed by ileum, lymph node, spleen, cerebellum and cerebrum. A tendency towards increased PrP mRNA levels and genetic susceptibility was observed in central nervous system. However, the results did not support the hypothesis that PrP mRNA levels vary between genotypes. Conclusion The results on PrP gene expression presented here provide valuable baseline data for future studies on scrapie pathogenesis. On the other hand, the results on stability data of several HK genes reported in this study could prove very useful in other gene expression studies carried out in these relevant ovine tissues.
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Affiliation(s)
- David Garcia-Crespo
- Department of Animal Health, Instituto Vasco de Investigación y Desarrollo Agrario (NEIKER); Berreaga, 1. 48160 Derio, Bizkaia, Spain
| | - Ramón A Juste
- Department of Animal Health, Instituto Vasco de Investigación y Desarrollo Agrario (NEIKER); Berreaga, 1. 48160 Derio, Bizkaia, Spain
| | - Ana Hurtado
- Department of Animal Health, Instituto Vasco de Investigación y Desarrollo Agrario (NEIKER); Berreaga, 1. 48160 Derio, Bizkaia, Spain
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Castilla J, Brun A, Díaz-San Segundo F, Salguero FJ, Gutiérrez-Adán A, Pintado B, Ramírez MA, del Riego L, Torres JM. Vertical transmission of bovine spongiform encephalopathy prions evaluated in a transgenic mouse model. J Virol 2005; 79:8665-8. [PMID: 15956610 PMCID: PMC1143732 DOI: 10.1128/jvi.79.13.8665-8668.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work we show evidence of mother-to-offspring transmission in a transgenic mouse line expressing bovine PrP (boTg) experimentally infected by intracerebral administration of bovine spongiform encephalopathy (BSE) prions. PrP(res) was detected in brains of newborns from infected mothers only when mating was allowed near to the clinical stage of disease, when brain PrP(res) deposition could be detected by Western blot analysis. Attempts to detect infectivity in milk after intracerebral inoculation in boTg mice were unsuccessful, suggesting the involvement of other tissues as carriers of prion dissemination. The results shown here prove the ability of BSE prions to spread centrifugally from the central nervous system to peripheral tissues and to offspring in a mouse model. Also, these results may complement previous epidemiological data supporting the occurrence of vertical BSE transmission in cattle.
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Affiliation(s)
- J Castilla
- Centro de Investigación en Sanidad Animal (CISA-INIA), Ctra. de Valdeolmes a El Casar, Valdeolmos, 28130 Madrid, Spain
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Garcia-Crespo D, Oporto B, Gomez N, Nagore D, Benedicto L, Juste RA, Hurtado A. PrP polymorphisms in Basque sheep breeds determined by PCR-restriction fragment length polymorphism and real-time PCR. Vet Rec 2004; 154:717-22. [PMID: 15214515 DOI: 10.1136/vr.154.23.717] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Two new PCR-based methods were developed to decode prion protein (PrP) gene polymorphisms at codons 136, 154 and 171: a PCR-restriction fragment length polymorphism (RFLP) analysis consisting of two PCR reactions followed by three enzymatic digestions, and a real-time PCR consisting of four reactions with seven fluorogenic probes. Both methods were used to study the distribution of PrP gene polymorphisms in a representative sample (1297 animals) of the populations of the two native breeds of sheep of the Spanish Basque Country, Latxa and Carranzana. Fourteen genotypes were found in the Latxa breed, in which ARQ/ARQ was the genotype most frequently observed (49.3 per cent), followed by ARR/ARQ (32.6 per cent) and ARQ/ARH (5.8 per cent). The genotype associated with the highest resistance to scrapie (ARR/ARR) was present in 5 per cent of the animals analysed. Similar results were observed in the Carranzana sheep.
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Affiliation(s)
- D Garcia-Crespo
- Departamento de Sanidad Animal, Instituto Vasco de Investigacíon y Desarrollo Agrario (NEIKER), Berreaga Kalea, 1,48160 Derio (Bizkaia), Spain
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Ryder S, Dexter G, Bellworthy S, Tongue S. Demonstration of lateral transmission of scrapie between sheep kept under natural conditions using lymphoid tissue biopsy. Res Vet Sci 2004; 76:211-7. [PMID: 15046955 DOI: 10.1016/j.rvsc.2003.11.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2003] [Indexed: 10/26/2022]
Abstract
Scrapie free adult sheep were introduced to a sheep flock specifically maintained to maximise scrapie infection. Native born sheep of the highly susceptible VRQ/VRQ genotype in this flock show highly efficient transmission, evidenced by 100% infection, with an age at death of less than 2 years. Infection in introduced sheep was identified by biopsy of tonsilar and nictitating membrane lymphoid tissue. Progeny of these sheep were monitored and clinical disease confirmed by examination of the brain using routine diagnostic methods. Naïve sheep of New Zealand origin introduced to the flock in adulthood became infected, demonstrating that lateral transmission had occurred. Lambs born to introduced ewes became infected and died at the same age as lambs born to native ewes, consistent with lateral transmission of scrapie to lambs. Although maternal transmission cannot be totally excluded for the lambs in this study, the data are consistent with lateral transmission being the most important means of spread leading to the high incidence of scrapie observed in this flock.
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Affiliation(s)
- S Ryder
- Department of Pathology, Veterinary Laboratories Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK.
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Jeffrey M, González L. Pathology and pathogenesis of bovine spongiform encephalopathy and scrapie. Curr Top Microbiol Immunol 2004; 284:65-97. [PMID: 15148988 DOI: 10.1007/978-3-662-08441-0_3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In common with other prion diseases or transmissible spongiform encephalopathies (TSEs), scrapie of sheep and bovine spongiform encephalopathy (BSE) are characterized by grey matter vacuolation and accumulation of an abnormal isoform of the host prion protein (PrP) in the central nervous system (CNS). In apparent contrast with human disease, neither neuronal loss nor gliosis are invariable features of the pathology of domestic food animal TSEs. In sheep, accumulation of abnormal PrP may also occur in the lymphoreticular and peripheral nervous systems where it may be detected within months of birth. The involvement of tissues other than CNS is influenced by dose, PrP genotype of the host and strain of TSE agent. Although many different strains of scrapie agent have been isolated in rodents following serial passage of affected sheep brain tissue, the significance of these murine strains for natural sheep scrapie, and the extent to which different sheep scrapie strains occur naturally are uncertain. Whereas the consistent vacuolar pattern in the brains of BSE-affected cattle suggests a single strain of agent, the patterns of vacuolation in sheep scrapie are highly variable and cannot be easily used to define strain. In sheep scrapie, immunohistochemistry can be used to visualize different morphological types of abnormal PrP within individual brains. These different types of PrP accumulation seem to be associated with different brain cell types and with variation in the processing of abnormal PrP. When assessed in whole brain, different patterns of PrP accumulation are helpful in distinguishing between different sheep scrapie strains and also between ovine BSE and natural sheep scrapie.
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Affiliation(s)
- M Jeffrey
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK.
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Healy AM, Weavers E, McElroy M, Gomez-Parada M, Collins JD, O'Doherty E, Sweeney T, Doherty ML. The Clinical Neurology of Scrapie in Irish Sheep. J Vet Intern Med 2003; 17:908-16. [PMID: 14658730 DOI: 10.1111/j.1939-1676.2003.tb02532.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
One hundred twenty-nine sheep with scrapie were identified from 20 flocks in which scrapie previously had been confirmed. Physical and neurologic examinations were performed on all animals. Videotape recordings were made and reviewed to assess gait. These procedures were repeated in 46 sheep at 2- to 3-week intervals until recumbency or inappetence necessitated euthanasia. Confirmation of scrapie was made by histopathologic and immunohistochemical examinations of brain tissue. The clinical signs most frequently recorded in the 129 animals on initial presentation were hindlimb ataxia (71%), head tremor (61%), altered mental status (57%), positive nibble reflex (51%), crouching posture (51%), teeth grinding (44%), low head carriage (38%), body condition score (BCS) < 1.5 (38%), and conscious proprioceptive deficits of the hindlimbs (36%). Progression of the disease was characterized by an increase in the frequency and severity of ataxia, weakness and hypermetria of the hindlimbs, a decreasing sway response, a decreasing extensor response to thoracolumbar pressure, and a reduction in the BCS. No effect of farm of origin on the clinical presentation could be shown. The presence of a nibble reflex was strongly associated (P < .0005) with prion protein (PrP) genotypes AA136RR154QH171 and AA136RR154QQ171. Logistic regression modeling of groups with associated clinical signs showed that animals with a crouching posture (odds ratio [OR], 20.036) and an abnormal yield to thoracolumbar pressure (OR, 7.117) were at increased risk of ataxia. Pruritus (OR, 0.168) was negatively associated with ataxia. Pruritus (OR, 4.974) and teeth grinding (OR, 4.279) were associated with a positive nibble reflex.
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Affiliation(s)
- Anne M Healy
- Department of Large Animal Clinical Studies Faculty of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
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González L, Martin S, Jeffrey M. Distinct profiles of PrP(d) immunoreactivity in the brain of scrapie- and BSE-infected sheep: implications for differential cell targeting and PrP processing. J Gen Virol 2003; 84:1339-1350. [PMID: 12692301 DOI: 10.1099/vir.0.18800-0] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous studies have shown that the patterns of disease-specific prion protein (PrP(d)) accumulation in the brain (the 'PrP(d) profile') of scrapie-affected sheep are mainly influenced by the source of scrapie agent. We have now extended those studies to investigate the effect of different PrP antibodies on the PrP(d) profile of scrapie- and bovine spongiform encephalopathy (BSE)-affected sheep. Immunohistochemical examination of brains of 20 sheep was performed with four different PrP antibodies (P4, 521.7, 505.2 and R486), and the animals were allocated to four groups of five sheep each depending on the transmissible spongiform encephalopathy (TSE) agent source (two natural scrapie sources, SSBP/1 and BSE). Although the PrP(d) profiles depended on the antibody used, the four TSE sources could always be differentiated. Natural Suffolk scrapie showed the highest levels of glia-associated PrP(d), natural Welsh Mountain scrapie uniquely had consistent vascular PrP(d) plaques, SSBP/1 produced the highest intracellular accumulations of PrP(d) and BSE led to moderate accumulation of all PrP(d) patterns except for vascular plaques. The variations in PrP(d) profile between TSE sources appeared to be the result of variations in cell tropism and in PrP processing. These processing differences are possibly associated with changes in PrP(d) conformation, and are manifest as differences in intracellular truncation and in release to the extracellular space of the abnormal protein. Moreover, variations in PrP(d) conformation would appear to be also influenced by the cell type supporting infection, arguing that it is modulated by the interaction between the infectious agent and the host.
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Affiliation(s)
- Lorenzo González
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, UK
| | - Stuart Martin
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, UK
| | - Martin Jeffrey
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, UK
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