scholarly journals Epidemiological analysis of data for scrapie in Great Britain

2005 ◽  
Vol 134 (2) ◽  
pp. 359-367 ◽  
Author(s):  
T. J. HAGENAARS ◽  
C. A. DONNELLY ◽  
N. M. FERGUSON
Keyword(s):  
Great Britain ◽  
Selective Breeding ◽  
Large Fraction ◽  
Epidemiological Studies ◽  
Transmissible Spongiform Encephalopathies ◽  
Limited Data ◽  
Spongiform Encephalopathies ◽  
Sheep Population ◽  
Epidemiological Analysis ◽  
Control And Eradication

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.

Transmission dynamics and mechanisms of endemicity of scrapie in the UK sheep population

2008 ◽  
Vol 137 (6) ◽  
pp. 762-774 ◽  
Author(s):  
J. E. TRUSCOTT ◽  
N. M. FERGUSON
Keyword(s):  
Structural Diversity ◽  
Epidemiological Data ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Sheep Population ◽  
Mean Values ◽  
The United Kingdom ◽  
The Family ◽  
The Uk

SUMMARYScrapie is a fatal neurological disease of sheep which is endemic in the United Kingdom. It is one of the family of transmissible spongiform encephalopathies (TSEs) that includes BSE. In this paper, we developed a micro-simulation model for scrapie in the UK sheep population, incorporating the genetic and structural diversity of the population and infectious contact between flocks through trading. The simulation was fitted to epidemiological data from a range of sources. We found a detection/reporting probability of 16% (95% CI 12–17) for animals dying of scrapie. Prevalence of infected animals in the population was about 0·15%. Infected individuals were found in 9% of flocks overall, rising to 60% in Shetland and 75% in Swaledale flocks. Mean values of R0 for flocks varied with breed from 2·43 (Shetland) to 0·21 (Suffolk). We also examined the possible long-term persistence of scrapie in the UK flock in the absence of any intervention.

scholarly journals Demographic risk factors for classical and atypical scrapie in Great Britain

2007 ◽  
Vol 88 (12) ◽  
pp. 3486-3492 ◽  
Author(s):  
Darren M. Green ◽  
Victor J. del Rio Vilas ◽  
Colin P. D. Birch ◽  
Jethro Johnson ◽  
Istvan Z. Kiss ◽  
...  
Keyword(s):  
European Union ◽  
Great Britain ◽  
Classical Scrapie ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Atypical Scrapie ◽  
The European Union ◽  
Spongiform Encephalopathies ◽  
Breeding Programmes ◽  
Trading Network

Following the bovine spongiform encephalopathy (BSE) crisis, the European Union has introduced policies for eradicating transmissible spongiform encephalopathies (TSEs), including scrapie, from large ruminants. However, recent European Union surveillance has identified a novel prion disease, ‘atypical’ scrapie, substantially different from classical scrapie. It is unknown whether atypical scrapie is naturally transmissible or zoonotic, like BSE. Furthermore, cases have occurred in scrapie-resistant genotypes that are targets for selection in legislated selective breeding programmes. Here, the first epidemiological study of British cases of atypical scrapie is described, focusing on the demographics and trading patterns of farms and using databases of recorded livestock movements. Triplet comparisons found that farms with atypical scrapie stock more sheep than those of the general, non-affected population. They also move larger numbers of animals than control farms, but similar numbers to farms reporting classical scrapie. Whilst there is weak evidence of association through sheep trading of farms reporting classical scrapie, atypical scrapie shows no such evidence, being well-distributed across regions of Great Britain and through the sheep-trading network. Thus, although cases are few in number so far, our study suggests that, should natural transmission of atypical scrapie be occurring at all, it is doing so slowly.

Physicochemical and biological characterizations of distinct strains of the transmissible mink encephalopathy agent

1994 ◽  
Vol 343 (1306) ◽  
pp. 413-414 ◽  
Keyword(s):  
Great Britain ◽  
Prion Proteins ◽  
The United States ◽  
Biological Properties ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Scrapie Agent ◽  
Transmissible Mink Encephalopathy ◽  
Sheep Scrapie ◽  
Disease Specific

Inoculation of the Stetsonville, Wisconsin source of transmissible mink encephalopathy (TME) into Syrian hamsters has identified two strains of the tme agent having distinct biological properties and producing disease-specific prion proteins (PrP tme ) having different physicochemical properties. Although several strains of the sheep scrapie agent have been identified in Great Britain, this is the first indication that agents producing transmissible spongiform encephalopathies in the United States also are capable of producing distinct strains.

Bovine Spongiform Encephalopathy: Hypothetical Risk of Emergence as a Zoonotic Foodborne Epidemic

1996 ◽  
Vol 59 (10) ◽  
pp. 1106-1111 ◽  
Author(s):  
HARLEY W. MOON
Keyword(s):  
Great Britain ◽  
Bovine Spongiform Encephalopathy ◽  
Prion Diseases ◽  
Oral Route ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Infected Cattle ◽  
Spongiform Encephalopathies ◽  
Clinically Normal ◽  
Zoological Parks

Bovine spongiform encephalopathy (BSE) is a fatal neurological disease of cattle, recognized in Great Britain in 1986. Cases in other countries have been attributed to imports from Great Britain. The disease has not occurred in the U.S. BSE is one of a group of diseases (other examples are scrapie of sheep and Creutzfeld-Jacob disease of humans) referred to as prion diseases or transmissible spongiform encephalopathies. Under some circumstances prion diseases can be transmitted by injection or by feeding infected (abnormal prion protein-containing) tissue to susceptible hosts. BSE was disseminated by feeding meat and bone meal containing BSE agent which was not completely inactivated by rendering. BSE is hypothesized to have emerged from scrapie via recycling of rendered by-products in cattle. There is also evidence of spontaneous feed-borne transmission of BSE to wild ruminants in zoological parks and to domestic cats. It has been hypothesized that foodborne transmission of BSE to humans has occurred or could occur. This hypothesis can neither be definitively refuted nor supported. However, it seems unlikely. In spite of hundreds of years of human exposure to scrapie, there is no evidence of transmission of scrapie to humans. Even if BSE is ultimately found to be somehow transmissible to humans, the risk of foodborne transmission appears to be low for several reasons: (i) The oral route is several orders of magnitude less sensitive than the parenteral route for transmission of prion diseases; (ii) the BSE agent is only detectable in brain, spinal cord, and intestine of infected cattle, tissues infrequently used for human food; and (iii) Great Britain (where the disease occurs) destroys and bans the use of all tissues from BSE-infected cattle as well as the brains, spinal cords, and intestinal tracts from clinically normal cattle.

Metallic prions

2004 ◽  
Vol 71 ◽  
pp. 193-202 ◽  
Author(s):  
David R Brown
Keyword(s):  
Prion Protein ◽  
Binding Capacity ◽  
Normal Function ◽  
Transmissible Spongiform Encephalopathies ◽  
Published Data ◽  
Normal Brain ◽  
Copper Binding ◽  
Loss Of Function ◽  
Spongiform Encephalopathies ◽  
The Brain

Prion diseases, also referred to as transmissible spongiform encephalopathies, are characterized by the deposition of an abnormal isoform of the prion protein in the brain. However, this aggregated, fibrillar, amyloid protein, termed PrPSc, is an altered conformer of a normal brain glycoprotein, PrPc. Understanding the nature of the normal cellular isoform of the prion protein is considered essential to understanding the conversion process that generates PrPSc. To this end much work has focused on elucidation of the normal function and activity of PrPc. Substantial evidence supports the notion that PrPc is a copper-binding protein. In conversion to the abnormal isoform, this Cu-binding activity is lost. Instead, there are some suggestions that the protein might bind other metals such as Mn or Zn. PrPc functions currently under investigation include the possibility that the protein is involved in signal transduction, cell adhesion, Cu transport and resistance to oxidative stress. Of these possibilities, only a role in Cu transport and its action as an antioxidant take into consideration PrPc's Cu-binding capacity. There are also more published data supporting these two functions. There is strong evidence that during the course of prion disease, there is a loss of function of the prion protein. This manifests as a change in metal balance in the brain and other organs and substantial oxidative damage throughout the brain. Thus prions and metals have become tightly linked in the quest to understand the nature of transmissible spongiform encephalopathies.

scholarly journals Effect of Scrapie Prion Infection in Ovine Bone Marrow-Derived Mesenchymal Stem Cells and Ovine Mesenchymal Stem Cell-Derived Neurons

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1137
Author(s):  
Laura García-Mendívil ◽  
Diego R. Mediano ◽  
Adelaida Hernaiz ◽  
David Sanz-Rubio ◽  
Francisco J. Vázquez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Post Inoculation ◽  
Spongiform Encephalopathies ◽  
Prion Infection ◽  
Over Time

Scrapie is a prion disease affecting sheep and goats and it is considered a prototype of transmissible spongiform encephalopathies (TSEs). Mesenchymal stem cells (MSCs) have been proposed as candidates for developing in vitro models of prion diseases. Murine MSCs are able to propagate prions after previous mouse-adaptation of prion strains and, although ovine MSCs express the cellular prion protein (PrPC), their susceptibility to prion infection has never been investigated. Here, we analyze the potential of ovine bone marrow-derived MSCs (oBM-MSCs), in growth and neurogenic conditions, to be infected by natural scrapie and propagate prion particles (PrPSc) in vitro, as well as the effect of this infection on cell viability and proliferation. Cultures were kept for 48–72 h in contact with homogenates of central nervous system (CNS) samples from scrapie or control sheep. In growth conditions, oBM-MSCs initially maintained detectable levels of PrPSc post-inoculation, as determined by Western blotting and ELISA. However, the PrPSc signal weakened and was lost over time. oBM-MSCs infected with scrapie displayed lower cell doubling and higher doubling times than those infected with control inocula. On the other hand, in neurogenic conditions, oBM-MSCs not only maintained detectable levels of PrPSc post-inoculation, as determined by ELISA, but this PrPSc signal also increased progressively over time. Finally, inoculation with CNS extracts seems to induce the proliferation of oBM-MSCs in both growth and neurogenic conditions. Our results suggest that oBM-MSCs respond to prion infection by decreasing their proliferation capacity and thus might not be permissive to prion replication, whereas ovine MSC-derived neuron-like cells seem to maintain and replicate PrPSc.

scholarly journals Backbone NMR assignments of the C-terminal domain of the human prion protein and its disease‐associated T183A variant

2021 ◽  
Vol 15 (1) ◽  
pp. 193-196
Author(s):  
Máximo Sanz-Hernández ◽  
Alfonso De Simone
Keyword(s):  
Prion Protein ◽  
Nmr Assignments ◽  
Chemical Shifts ◽  
Prion Diseases ◽  
Random Coil ◽  
Transmissible Spongiform Encephalopathies ◽  
Globular Domain ◽  
Structural Elements ◽  
Spongiform Encephalopathies ◽  
Human Prion Protein

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders associated with the misfolding and aggregation of the human prion protein (huPrP). Despite efforts into investigating the process of huPrP aggregation, the mechanisms triggering its misfolding remain elusive. A number of TSE-associated mutations of huPrP have been identified, but their role at the onset and progression of prion diseases is unclear. Here we report the NMR assignments of the C-terminal globular domain of the wild type huPrP and the pathological mutant T183A. The differences in chemical shifts between the two variants reveal conformational alterations in some structural elements of the mutant, whereas the analyses of secondary shifts and random coil index provide indications on the putative mechanisms of misfolding of T183A huPrP.

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