SCRAPIE USA

Transmissible Spongiform Encephalopathy TSE Prion PrP sheep and goats

About Me

My Photo
Name:
Location: BACLIFF, Texas, United States

My mother was murdered by what I call corporate and political homicide i.e. FOR PROFIT! she died from a rare phenotype of CJD i.e. the Heidenhain Variant of Creutzfeldt Jakob Disease i.e. sporadic, simply meaning from unknown route and source. I have simply been trying to validate her death DOD 12/14/97 with the truth. There is a route, and there is a source. There are many here in the USA. WE must make CJD and all human TSE, of all age groups 'reportable' Nationally and Internationally, with a written CJD questionnaire asking real questions pertaining to route and source of this agent. Friendly fire has the potential to play a huge role in the continued transmission of this agent via the medical, dental, and surgical arena. We must not flounder any longer. ...TSS

Tuesday, October 13, 2026

Evidence for multiple prion conformers in natural scrapie isolates

 Evidence for multiple prion conformers in natural scrapie isolates


Imamura ,Kohtaro Miyazawa ,Hiroyuki Okada,Minako Ohno,Hiromi Iguchi,Yuichi Matsuura,Yoshifumi Iwamaru,Hanae Takatsuki,Tsuyoshi Mori,Jiyan Ma,Ryuichiro Atarashi

Published: September 17, 2026

https://doi.org/10.1371/journal.ppat.1014283

Abstract

Prion strains in infected animals may exist as heterogeneous populations composed of a major prion conformer responsible for the dominant disease phenotype and minor conformers that are phenotypically silent or difficult to detect. However, the presence and biological significance of such minor conformers in natural prion isolates remain poorly understood. Identifying and characterizing these hidden substrains is important for understanding prion strain diversity and for assessing potential transmission risks to humans and livestock. In this study, we utilized a modified protein misfolding cyclic amplification (PMCA) method to detect substrains within classical scrapie isolates. Our analysis provided evidence consistent with the coexistence of multiple prion conformers, including previously unrecognized conformers, within single prion isolates. Furthermore, we observed changes in the detectable substrain composition during passages in animal hosts. These findings support the idea that scrapie prion populations can contain diverse conformers and that changes in detectable conformer populations during passage may contribute to the overall diversity of scrapie prions.

Author summary

Prions are infectious proteins that can cause fatal neurodegenerative diseases in humans and animals. Different prion strains can produce different disease patterns, even when the host prion protein has the same amino acid sequence. Natural prion infections may contain not only the major strain that determines the apparent disease type, but also minor hidden variants that are difficult to detect. These hidden variants may become important when prions pass into a new host or are transmitted repeatedly. In this study, we used a highly sensitive in vitroamplification method to examine scrapie prions from naturally and experimentally infected animals. This approach allowed us to detect prion variants that were not readily visible by conventional biochemical methods. Our results provide evidence that scrapie isolates can contain multiple prion conformers and that the detectable composition of these conformers can change during passage. These findings suggest that hidden prion diversity may contribute to changes in prion strain properties during transmission, although the results of in vitroamplification should be interpreted together with biological data from animal studies.

snip…

The propagation of classical scrapie in wild-type mice is known to generate diverse mouse-adapted scrapie strains [37–39]. Here, we provide evidence for diversity in the composition of latent conformers within classical scrapie and CH1641-like isolates. These findings suggest that latent conformers may potentially replace the dominant phenotypic conformer when propagated in new environments (e.g., a new host species), leading to the emergence of distinct prion diseases in the new host. Collectively, this raises concerns that newly identified conformers, including C2, CH2, and L types, may warrant consideration with respect to potential interspecies transmission risks to other species, such as cattle and humans. To elucidate the risk of interspecies transmission of these hidden prion conformers, bioassays combining PMCA products and transgenic mice expressing the PrPC derived from various animal species will be required.

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014283

Evidence for multiple prion conformers in natural scrapie isolates

September 17, 2026

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014283

I am reminded of the ch1641 strain that is like BSE ;

***> In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641.

Title: ASSESSMENT OF THE GENETIC RISK AND IMPACT OF LATERAL TRANSMISSION IN A VALINE-ASSOCIATED SCRAPIE OUTBREAK IN SHEEP

Author item.gif EVONIUK, J - NORTH DAKOTA STATE UNIV item.gif STOLTENOW, C - NORTH DAKOTA STATE UNIV item.gif O'Rourke, Katherine item.gif MOORE, B - NORTH DAKOTA STATE UNIV item.gif REDMER, D - NORTH DAKOTA STATE UNIV

Submitted to: American Journal of Veterinary Research Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/8/2005 Publication Date: 8/1/2005 Citation: Evoniuk, J.M., Stoltenow, C.L., O'Rourke, K.I., Moore, B.L., Redmer, D.A. 2005.

Assessment of the genetic risk and impact of lateral transmission in a valine-associated scrapie outbreak in sheep.

American Journal of Veterinary Research. 66(8):1-6. Interpretive

Summary: Scrapie is a fatal neurologic disease of sheep, endemic in the US but the subject of a vigorous eradication program. Scrapie is associated with accumulation of a misfolded form of the sheep prion protein. Control measures in an infected flock include removal of all genetically susceptible sheep. Susceptibility is controlled by naturally occurring differences in the prion protein, designated 171Q (susceptible) or 171R (generally resistant). The resistance of sheep with the 171R form of the gene occurs with one scrapie strain, the most US strain, but these sheep are not protected from the alternative strain, identified as valine associated scrapie. Anecdotal reports have shown that the strain probably occurs in the US but is relatively rare. In this publication, the presence of the valine associated strain was demonstrated through epidemiology and genetic analysis of a large flock of sheep. The study demonstrated that this scrapie strain can infect sheep as adults and is spread efficiently among related and unrelated sheep housed together during lambing seasons. The results suggest that the outbreak was due to the relatively high number of sheep with the susceptible form of the gene, probably introduced through the use of highly prolific rams carrying the gene. Further, transmission of the disease among adults, the prolonged incubation time, the unsuitability of some susceptible sheep to live animal testing, and susceptibility of sheep with the 171R gene suggest that removal of sheep with the genotype AVQR from infected flocks would be prudent.

Technical Abstract: Scrapie is a member of the heterogenous family of transmissible spongiform encephalopathies. Although these disorders appear to be related to misfolding of a host protein rather than an exogenous organism, two distinct disease phenotypes or strains are noted in sheep. Characterization of the scrapie strains in experimental and field settings in the United Kingdom and Europe have included differences in incubation time, survival rates, lateral transmission efficiency and most importantly, genetic susceptibility. Sheep of the prototype strain SSPB/1 are susceptible only if the PRNP (prion protein precursor gene) encodes valine (V) at codon 136; a polymorphism (encoding glutamine to arginine) at codon 171 apparently reduces disease prevalence but increases incubation time and limits tissue distribution to the brain. Sheep with the prototype valine-independent strain CH1641 are susceptible only if homozygous for glutamine (Q) at codon 171. In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641. The only genotype useful for strain discrimination is the relatively rare 136AV/171QR. In this study, a flock of sheep with a large number of infected sheep was analyzed. The presence of at least one V136 allele was identified in all but 2 sheep in the study, incubation times were very short in V136 homozygous sheep, probable lateral transmission was demonstrated in 15 sheep, and at least one AVQR sheep was identified. Therefore, this outbreak was probably due to a valine-associated (SSBP/1-like) strain and this report is the first full description of the epidemiology of this strain in US sheep. The high rate of lateral transmission and the susceptibility of 136AV/171QR sheep to scrapie suggest that genotyping for codon 136 may assist management decisions following a scrapie diagnosis and that it may be prudent to remove sheep of the 136AV/171QR genotype from infected flocks.

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=182469

posted by Terry S. Singeltary Sr. | 1:51 PM

0 Comments:

Post a Comment

Subscribe to Post Comments [Atom]

<< Home