Diagnosis of Transmissible Spongiform Encephalopathies in Animals: A Review

Transmissible spongiform encephalopathies (TSEs) in animals include, among others, bovine spongiform encephalopathy (BSE), scrapie, chronic wasting disease, and atypical forms of prion diseases. Diagnosis of TSEs is based on identification of characteristic lesions or on detection of the abnormal prion proteins in tissues, often by use of their partial proteinase K resistance property. Correctly sampling of target tissues is of utmost importance as this has a considerable effect on test sensitivity. Most of the rapid or screening tests are based on ELISA or Western immunoblot (WB) analysis, and many are officially approved. Confirmatory testing is normally performed by use of histologic examination, immunohistochemical analysis, certain WB protocols, or detection of prion fibrils by use of electron microscopy (scrapie-associated fibril). The discriminatory methods for diagnostic use are mostly based on WB technology and provide initial identification of the prion strain, particularly for differentiation of BSE from scrapie in small ruminants. Definitive prion strain characterization is performed by use of bioassays, usually in mice. A burgeoning number of transgenic mice have been developed for TSE studies. Development of new tests with higher sensitivity and of more reliable diagnostic applications for live animals tested for food safety reasons is a rapidly developing field. Ultimately, the choice of a test for TSE diagnosis depends on the rationale for the testing.

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Neuropathology of Animal Prion Diseases

Biomolecules ◽

10.3390/biom11030466 ◽

2021 ◽

Vol 11 (3) ◽

pp. 466

Author(s):

Leonor Orge ◽

Carla Lima ◽

Carla Machado ◽

Paula Tavares ◽

Paula Mendonça ◽

...

Keyword(s):

Prion Diseases ◽

Clinical Signs ◽

Small Ruminants ◽

Neuronal Loss ◽

Cellular Prion Protein ◽

Brain Inflammation ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Spongiform Encephalopathies ◽

Lesion Profile

Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are a fatal group of infectious, inherited and spontaneous neurodegenerative diseases affecting human and animals. They are caused by the conversion of cellular prion protein (PrPC) into a misfolded pathological isoform (PrPSc or prion- proteinaceous infectious particle) that self-propagates by conformational conversion of PrPC. Yet by an unknown mechanism, PrPC can fold into different PrPSc conformers that may result in different prion strains that display specific disease phenotype (incubation time, clinical signs and lesion profile). Although the pathways for neurodegeneration as well as the involvement of brain inflammation in these diseases are not well understood, the spongiform changes, neuronal loss, gliosis and accumulation of PrPSc are the characteristic neuropathological lesions. Scrapie affecting small ruminants was the first identified TSE and has been considered the archetype of prion diseases, though atypical and new animal prion diseases continue to emerge highlighting the importance to investigate the lesion profile in naturally affected animals. In this report, we review the neuropathology and the neuroinflammation of animal prion diseases in natural hosts from scrapie, going through the zoonotic bovine spongiform encephalopathy (BSE), the chronic wasting disease (CWD) to the newly identified camel prion disease (CPD).

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Prion Disease Blood Test Using Immunoprecipitation and Improved Quaking-Induced Conversion

mBio ◽

10.1128/mbio.00078-11 ◽

2011 ◽

Vol 2 (3) ◽

Cited By ~ 78

Author(s):

Christina D. Orrú ◽

Jason M. Wilham ◽

Lynne D. Raymond ◽

Franziska Kuhn ◽

Björn Schroeder ◽

...

Keyword(s):

Real Time ◽

Blood Test ◽

Prion Diseases ◽

Proteinase K ◽

Transmissible Spongiform Encephalopathies ◽

Serum Samples ◽

Spongiform Encephalopathies ◽

Jakob Disease

ABSTRACT A key challenge in managing transmissible spongiform encephalopathies (TSEs) or prion diseases in medicine, agriculture, and wildlife biology is the development of practical tests for prions that are at or below infectious levels. Of particular interest are tests capable of detecting prions in blood components such as plasma, but blood typically has extremely low prion concentrations and contains inhibitors of the most sensitive prion tests. One of the latter tests is quaking-induced conversion (QuIC), which can be as sensitive as in vivo bioassays, but much more rapid, higher throughput, and less expensive. Now we have integrated antibody 15B3-based immunoprecipitation with QuIC reactions to increase sensitivity and isolate prions from inhibitors such as those in plasma samples. Coupling of immunoprecipitation and an improved real-time QuIC reaction dramatically enhanced detection of variant Creutzfeldt-Jakob disease (vCJD) brain tissue diluted into human plasma. Dilutions of 1014-fold, containing ~2 attogram (ag) per ml of proteinase K-resistant prion protein, were readily detected, indicating ~10,000-fold greater sensitivity for vCJD brain than has previously been reported. We also discriminated between plasma and serum samples from scrapie-infected and uninfected hamsters, even in early preclinical stages. This combined assay, which we call “enhanced QuIC” (eQuIC), markedly improves prospects for routine detection of low levels of prions in tissues, fluids, or environmental samples. IMPORTANCE Transmissible spongiform encephalopathies (TSEs) are largely untreatable and are difficult to diagnose definitively prior to irreversible clinical decline or death. The transmissibility of TSEs within and between species highlights the need for practical tests for even the smallest amounts of infectivity. A few sufficiently sensitive in vitro methods have been reported, but most have major limitations that would preclude their use in routine diagnostic or screening applications. Our new assay improves the outlook for such critical applications. We focused initially on blood plasma because a practical blood test for prions would be especially valuable for TSE diagnostics and risk reduction. Variant Creutzfeldt-Jakob disease (vCJD) in particular has been transmitted between humans via blood transfusions. Enhanced real-time quaking-induced conversion (eRTQ) provides by far the most sensitive detection of vCJD to date. The 15B3 antibody binds prions of multiple species, suggesting that our assay may be useful for clinical and fundamental studies of a variety of TSEs of humans and animals.

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Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Biomolecules ◽

10.3390/biom10030469 ◽

2020 ◽

Vol 10 (3) ◽

pp. 469

Author(s):

Hasier Eraña ◽

Jorge M. Charco ◽

Ezequiel González-Miranda ◽

Sandra García-Martínez ◽

Rafael López-Moreno ◽

...

Keyword(s):

Neurodegenerative Diseases ◽

Protein Misfolding ◽

Prion Diseases ◽

Immunohistochemical Analysis ◽

Body Fluids ◽

Detection Methods ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathies ◽

Prion Propagation

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrPSc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrPSc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrPSc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

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Susceptibility of Cattle to First-passage Intracerebral Inoculation with Chronic Wasting Disease Agent from White-tailed Deer

Veterinary Pathology ◽

10.1354/vp.44-4-487 ◽

2007 ◽

Vol 44 (4) ◽

pp. 487-493 ◽

Cited By ~ 43

Author(s):

A. N. Hamir ◽

J. M. Miller ◽

R. A. Kunkle ◽

S. M. Hall ◽

J. A. Richt

Keyword(s):

Chronic Wasting Disease ◽

Prion Diseases ◽

Clinical Signs ◽

Diagnostic Techniques ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Wasting Disease ◽

Spongiform Encephalopathies ◽

Disease Agent ◽

Sheep Scrapie

Fourteen, 3-month-old calves were intracerebrally inoculated with the agent of chronic wasting disease (CWD) from white-tailed deer (CWDwtd) to compare the clinical signs and neuropathologic findings with those of certain other transmissible spongiform encephalopathies (TSE, prion diseases) that have been shown to be experimentally transmissible to cattle (sheep scrapie, CWD of mule deer [CWDmd], bovine spongiform encephalopathy [BSE], and transmissible mink encephalopathy). Two uninoculated calves served as controls. Within 26 months postinoculation (MPI), 12 inoculated calves had lost considerable weight and eventually became recumbent. Of the 12 inoculated calves, 11 (92%) developed clinical signs. Although spongiform encephalopathy (SE) was not observed, abnormal prion protein (PrPd) was detected by immunohistochemistry (IHC) and Western blot (WB) in central nervous system tissues. The absence of SE with presence of PrPd has also been observed when other TSE agents (scrapie and CWDmd) were similarly inoculated into cattle. The IHC and WB findings suggest that the diagnostic techniques currently used to confirm BSE would detect CWDwtd in cattle, should it occur naturally. Also, the absence of SE and a distinctive IHC pattern of CWDwtd and CWDmd in cattle suggests that it should be possible to distinguish these conditions from other TSEs that have been experimentally transmitted to cattle.

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Human Prion Diseases

Escourolle and Poirier's Manual of Basic Neuropathology ◽

10.1093/med/9780199929054.003.0006 ◽

2013 ◽

pp. 149-160

Author(s):

James W. Ironside ◽

Matthew P. Frosch ◽

Bernardino Ghetti

Keyword(s):

Prion Diseases ◽

Neuronal Loss ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Pituitary Hormone ◽

Human Pituitary ◽

Spongiform Encephalopathies ◽

Jakob Disease ◽

Prnp Codon ◽

Codon 129

This chapter describes and illustrates the neuropathology of prion diseases, also known as transmissible spongiform encephalopathies. These diseases are characterized pathologically by varying combinations of spongiform change, neuronal loss, reactive gliosis, and prion protein (PrP) deposition. The morphologic pattern depends on the etiology of the disease and the genotype of the patient. Different clinicopathological phenotypes of sporadic Creutzfeldt-Jakob disease (CJD) have been described depending on the PRNP codon 129 genotype and the PrP isotype. A novel form known as variably protease-sensitive prionopathy has been recently identified. Familial prion diseases include familial CJD, Gerstmann-Sträussler-Scheinker disease, and fatal familial insomnia. Over 40 different PRNP mutations have been identified. Acquired prion diseases include Kuru; iatrogenic CJD, particularly in recipients of contaminated human pituitary hormone, and variant CJD, which seems closely related to bovine spongiform encephalopathy.

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Transmissible spongiform encephalopathy strain, PrP genotype and brain region all affect the degree of glycosylation of PrPSc

Journal of General Virology ◽

10.1099/vir.0.80251-0 ◽

2005 ◽

Vol 86 (1) ◽

pp. 241-246 ◽

Cited By ~ 17

Author(s):

Robert A. Somerville ◽

Scott Hamilton ◽

Karen Fernie

Keyword(s):

Prion Diseases ◽

Transmissible Spongiform Encephalopathy ◽

Infectious Agent ◽

Host Protein ◽

Transmissible Spongiform Encephalopathies ◽

Major Influence ◽

Spongiform Encephalopathy ◽

Phenotypic Properties ◽

Spongiform Encephalopathies ◽

Diagnostic Potential

Transmissible spongiform encephalopathies (TSEs), sometimes known as prion diseases, are caused by an infectious agent whose molecular properties have not been determined. Traditionally, different strains of TSE diseases are characterized by a series of phenotypic properties after passage in experimental animals. More recently it has been recognized that diversity in the degree to which an abnormal form of the host protein PrP, denoted PrPSc, is glycosylated and the migration of aglycosyl forms of PrPSc on immunoblots may have some differential diagnostic potential. It has been recognized that these factors are affected by the strain of TSE agent but also by other factors, e.g. location within the brain. This study shows in some cases, but not others, that host PrP genotype has a major influence on the degree of PrPSc glycosylation and migration on gels and provides further evidence of the effect of brain location. Accordingly both the degree of glycosylation and the apparent molecular mass of PrPSc may be of some value for differential diagnosis between TSE strains, but only when host effects are taken into account. Furthermore, the data inform the debate about how these differences arise, and favour hypotheses proposing that TSE agents affect glycosylation of PrP during its biosynthesis.

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Adaptation and Selection of Prion Protein Strain Conformations following Interspecies Transmission of Transmissible Mink Encephalopathy

Journal of Virology ◽

10.1128/jvi.74.12.5542-5547.2000 ◽

2000 ◽

Vol 74 (12) ◽

pp. 5542-5547 ◽

Cited By ~ 96

Author(s):

Jason C. Bartz ◽

Richard A. Bessen ◽

Debbie McKenzie ◽

Richard F. Marsh ◽

Judd M. Aiken

Keyword(s):

Incubation Period ◽

Prion Protein ◽

Prion Diseases ◽

Interspecies Transmission ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Spongiform Encephalopathies ◽

Strain Adaptation ◽

Transmissible Mink Encephalopathy ◽

Selection Of

ABSTRACT Interspecies transmission of the transmissible spongiform encephalopathies (TSEs), or prion diseases, can result in the adaptation and selection of TSE strains with an expanded host range and increased virulence such as in the case of bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease. To investigate TSE strain adaptation, we serially passaged a biological clone of transmissible mink encephalopathy (TME) into Syrian golden hamsters and examined the selection of distinct strain phenotypes and conformations of the disease-specific isoform of the prion protein (PrPSc). The long-incubation-period drowsy (DY) TME strain was the predominate strain, based on the presence of its strain-specific PrPSc following interspecies passage. Additional serial passages in hamsters resulted in the selection of the hyper (HY) TME PrPSc strain-dependent conformation and its short incubation period phenotype unless the passages were performed with a low-dose inoculum (e.g., 10−5 dilution), in which case the DY TME clinical phenotype continued to predominate. For both TME strains, the PrPSc strain pattern preceded stabilization of the TME strain phenotype. These findings demonstrate that interspecies transmission of a single cloned TSE strain resulted in adaptation of at least two strain-associated PrPScconformations that underwent selection until one type of PrPSc conformation and strain phenotype became predominant. To examine TME strain selection in the absence of host adaptation, hamsters were coinfected with hamster-adapted HY and DY TME. DY TME was able to interfere with the selection of the short-incubation HY TME phenotype. Coinfection could result in the DY TME phenotype and PrPSc conformation on first passage, but on subsequent passages, the disease pattern converted to HY TME. These findings indicate that during TSE strain adaptation, there is selection of a strain-specific PrPSc conformation that can determine the TSE strain phenotype.

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Cerebrospinal Fluid and Plasma Small Extracellular Vesicles and miRNAs as Biomarkers for Prion Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms22136822 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6822

Author(s):

Óscar López-Pérez ◽

David Sanz-Rubio ◽

Adelaida Hernaiz ◽

Marina Betancor ◽

Alicia Otero ◽

...

Keyword(s):

Cerebrospinal Fluid ◽

Protein Misfolding ◽

Prion Diseases ◽

Clinical Stage ◽

Proteinase K ◽

Transmissible Spongiform Encephalopathies ◽

Alternative Source ◽

Spongiform Encephalopathies ◽

In Vivo Diagnosis

Diagnosis of transmissible spongiform encephalopathies (TSEs), or prion diseases, is based on the detection of proteinase K (PK)-resistant PrPSc in post-mortem tissues as indication of infection and disease. Since PrPSc detection is not considered a reliable method for in vivo diagnosis in most TSEs, it is of crucial importance to identify an alternative source of biomarkers to provide useful alternatives for current diagnostic methodology. Ovine scrapie is the prototype of TSEs and has been known for a long time. Using this natural model of TSE, we investigated the presence of PrPSc in exosomes derived from plasma and cerebrospinal fluid (CSF) by protein misfolding cyclic amplification (PMCA) and the levels of candidate microRNAs (miRNAs) by quantitative PCR (qPCR). Significant scrapie-associated increase was found for miR-21-5p in plasma-derived but not in CSF-derived exosomes. However, miR-342-3p, miR-146a-5p, miR-128-3p and miR-21-5p displayed higher levels in total CSF from scrapie-infected sheep. The analysis of overexpressed miRNAs in this biofluid, together with plasma exosomal miR-21-5p, could help in scrapie diagnosis once the presence of the disease is suspected. In addition, we found the presence of PrPSc in most CSF-derived exosomes from clinically affected sheep, which may facilitate in vivo diagnosis of prion diseases, at least during the clinical stage.

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Prions and animal transmissible spongiform encephalopathies

Veterinarski glasnik ◽

10.2298/vetgl170302004j ◽

2017 ◽

Vol 71 (1) ◽

pp. 1-15

Author(s):

Polona Juntes ◽

Jelka Zabavnik-Piano ◽

Ambrozic Ivan

Keyword(s):

Prion Diseases ◽

Fatal Outcome ◽

Economic Consequences ◽

Control Measures ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Spongiform Encephalopathies ◽

Causative Agents ◽

Long Time ◽

And Control

Background. Transmissible spongiform encephalopathies (TSEs) or prion diseases are a unique group of neurodegenerative diseases of animals and humans, which always have a fatal outcome and are transmissible among animals of the same or different species. Scope and Approach. The aim of this work is to review some recent data about animal TSEs, with the emphasis on their causative agents and zoonotic potential, and to discuss why the surveillance and control measures over animal TSEs should remain in force. Key Findings and Conclusions. We still have incomplete knowledge of prions and prion diseases. Scrapie has been present for a very long time and controlled with varied success. Bovine spongiform encephalopathy (BSE) emerged unnoticed, and spread within a few years to epidemic proportions, entailing enormous economic consequences and public concerns. Currently, the classical BSE epidemic is under control, but atypical cases do, and probably will, persist in bovine populations. The Chronic Wasting Disease (CWD) of the cervids has been spreading in North America and has recently been detected in Europe. Preventive measures for the control of classical BSE remain in force, including the feed ban and removal of specified risk materials. However, active BSE surveillance has considerably decreased. In the absence of such preventive and control measures, atypical BSE cases in healthy slaughtered bovines might persist in the human food chain, and BSE prions might resurface. Moreover, other prion strains might emerge and spread undetected if the appropriate preventive and surveillance measures were to cease, leaving behind inestimable consequences.

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Detection and Control of Prion Diseases in Food Animals

ISRN Veterinary Science ◽

10.5402/2012/254739 ◽

2012 ◽

Vol 2012 ◽

pp. 1-24 ◽

Cited By ~ 7

Author(s):

Peter Hedlin ◽

Ryan Taschuk ◽

Andrew Potter ◽

Philip Griebel ◽

Scott Napper

Keyword(s):

Prion Disease ◽

Disease Transmission ◽

Management Practices ◽

Prion Diseases ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Case Scenario ◽

Worst Case ◽

Spongiform Encephalopathies ◽

Food Animals

Transmissible spongiform encephalopathies (TSEs), or prion diseases, represent a unique form of infectious disease based on misfolding of a self-protein (PrPC) into a pathological, infectious conformation (PrPSc). Prion diseases of food animals gained notoriety during the bovine spongiform encephalopathy (BSE) outbreak of the 1980s. In particular, disease transmission to humans, to the generation of a fatal, untreatable disease, elevated the perspective on livestock prion diseases from food production to food safety. While the immediate threat posed by BSE has been successfully addressed through surveillance and improved management practices, another prion disease is rapidly spreading. Chronic wasting disease (CWD), a prion disease of cervids, has been confirmed in wild and captive populations with devastating impact on the farmed cervid industries. Furthermore, the unabated spread of this disease through wild populations threatens a natural resource that is a source of considerable economic benefit and national pride. In a worst-case scenario, CWD may represent a zoonotic threat either through direct transmission via consumption of infected cervids or through a secondary food animal, such as cattle. This has energized efforts to understand prion diseases as well as to develop tools for disease detection, prevention, and management. Progress in each of these areas is discussed.

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