Wednesday, December 21, 2016

TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES 2016 ANNUAL REPORT ARS RESEARCH   

  
       
2016 Annual Report

1a. Objectives (from AD-416):

1. Investigate the pathobiology of atypical transmissible spongiform encephalopathies (TSEs) in natural hosts. A. Investigate the pathobiology of atypical scrapie. B. Investigate the pathobiology of atypical bovine spongiform encephalopathy (BSE). 2. Investigate the horizontal transmission of TSEs. A. Assess the horizontal transmission of sheep scrapie in the absence of lambing. B. Determine routes of transmission in chronic wasting disease (CWD) infected premises. C. Assess oral transmission of CWD in reindeer. 3. Investigate determinants of CWD persistence. A. Determine CWD host range using natural routes of transmission. B. Investigate the pathobiology of CWD.

1b. Approach (from AD-416):

The studies will focus on three animal transmissible spongiform encephalopathy (TSE) agents found in the United States: bovine spongiform encephalopathy (BSE); scrapie of sheep and goats; and chronic wasting disease (CWD) of deer, elk, and moose. The research will address sites of accumulation, routes of infection, environmental persistence, and ante mortem diagnostics with an emphasis on controlled conditions and natural routes of infection. Techniques used will include clinical exams, histopathology, immunohistochemistry and biochemical analysis of proteins. The enhanced knowledge gained from this work will help mitigate the potential for unrecognized epidemic expansions of these diseases in populations of animals that could either directly or indirectly affect food animals.

3. Progress Report:

This is the final report for the project 5030-32000-103-00D that started 10/01/2011 and terminates 09/30/2016. Research efforts directed toward meeting objective 1 of our project plan include work in previous years starting with the inoculation of animals for studies designed to address the pathobiology of atypical scrapie, atypical bovine spongiform encephalopathy (BSE), and a genetic version of BSE. Postmortem examination of the sheep inoculated with atypical scrapie has been initiated and laboratory analysis of the tissues is ongoing. Cattle inoculated with atypical BSE developed disease and evaluation of samples is currently underway. Cattle inoculated with a genetic form of BSE developed disease, and a manuscript reporting these results was published (2012). Comparisons of the stability of the disease agent from various BSE isolates have been completed and a study published (2013). Comprehensive laboratory comparisons of genetic BSE to atypical and classical BSE are ongoing. In research pertaining to objective 2, "Investigate the horizontal transmission of TSEs", we initiated a study to determine the risk of horizontal transmission of scrapie to neonatal or adult sheep in the absence of lambing of scrapie-infected ewes. At this time, scrapie-free ewes have lambed in the presence of sheep preclinically affected with scrapie. Both the lambs and ewes remain cohoused with the scrapie-affected sheep and are regularly examined for the onset of clinical signs suggestive of scrapie. Additional research demonstrated for the first time that chronic wasting disease is horizontally transmissible amongst reindeer, and a manuscript was published (2016) showing differences in susceptibility of sheep to the scrapie disease agent based on the prion genotype of the host animal, an important factor in horizontal transmission. Additional published research (2016) reports that the high degree of sequence conservation in the prion protein is not based on linkage to another gene and is specific to the prion protein. The fact that the observed sequence conservation of the prion gene is not due to linkage to another gene has implications for our understanding the normal functions of the prion protein.

4. Accomplishments

1. Different evolutionary pressures in domestic cattle influence the prion protein (PrP) and its nearest neighbor, a homolog of PrP known as doppel encoded by the PRND gene. The mammalian prion gene (PRNP) expresses a highly conserved protein termed the prion protein (PrP), best known as the causative agent of prion disease. Studies of PRNP knockout animals (animals that have had the PRNP gene deleted from their genome), including both mice and cattle, have failed to result in an overt change in animal behavior, health, or development. Some have used this to suggest that PrP is dispensable and that the high degree of sequence conservation is due to linkage to a nearby essential gene rather than due to high pressure to maintain the PrP sequence. In this work, ARS researchers in Ames, Iowa demonstrated the degree of sequence conservation in the nearest neighbor of PRNP, a gene known as PRND. We determined that in cattle PRND is not under any selective pressure and is not influencing PRNP nor is it being influenced in a manner similar to PRNP. This indicates an essential role for the protein PrP suggesting that the loss of prion function is simply not manifesting in the controlled environmental conditions used to raise the knockout animals. This has implications for understanding the normal function of the prion protein and for the use of PRNP knockout cattle in the production of prion free bovine products.
       
2. Reindeer are susceptible to chronic wasting disease (CWD) from various cervid sources and infected reindeer can transmit the disease to healthy reindeer. Chronic wasting disease (CWD) is a naturally-occurring, fatal prion disease of cervids. Reindeer are susceptible to CWD following experimental oral challenge. This study investigated the susceptibility of reindeer to intracranial inoculation of CWD from white-tailed deer, mule deer, or elk, and assessed for transmission to non-inoculated reindeer placed in direct (same pen) or indirect contact (adjacent pen but without nose-to-nose contact). Intracranially inoculated reindeer developed clinical disease from 21 months post-inoculation, and a specific disease associated protein was detected in 5 out of 6 reindeer that were in either direct or indirect contact. ARS researchers in Ames, Iowa demonstrated that reindeer are susceptible to CWD from various cervid sources and can transmit CWD to naïve reindeer through direct contact or indirectly through the environment. This has important regulatory implications for the transport of this species, especially following the recent discovery of CWD in a free-ranging reindeer of Norway.

3. Sheep prion protein genetics influences disease progression in sheep orally inoculated with scrapie. Sheep scrapie is a transmissible spongiform encephalopathy that can be transmitted through contact with affected animals resulting in significant economic losses in affected flocks. The prion protein gene (PRNP) profoundly influences the susceptibility of sheep to the scrapie agent and the tissue levels and distribution of the disease that is associated with the form of the prion protein (PrPSc) in affected sheep. ARS researchers in Ames, Iowa demonstrated the failure to detect PrPSc in nervous or lymphoid tissues of neonatal sheep of a specific PRNP genotype (ARQ/ARR) after oral inoculation with a U.S. scrapie isolate. Sheep of the ARQ/ARQ genotype receiving the same inoculum developed scrapie within 24 months. Lambs of the ARQ/ARR genotype that received the same inoculum by intracranial inoculation developed scrapie with a prolonged incubation period and with abnormal prion present within the central nervous system, but not peripheral lymphoid tissues. Results suggest that ARQ/ARR sheep are resistant to oral infection with the scrapie isolate used even during the neonatal period. This enhances the understanding of natural transmission of scrapie to sheep of specific genotypes in a production relevant setting including neonatal lambs.

5. Significant Activities that Support Special Target Populations:
None.

Review Publications

     
Haley, N.J., Siepker, C., Walter, W.D., Thomsen, B.V., Greenlee, J.J., Lehmkuhl, A.D., Richt, J.A. 2016. Antemortem detection of chronic wasting disease prions in nasal brush collections and rectal biopsy specimens from white-tailed deer by real time quaking-induced conversion. Journal of Clinical Microbiology. 54(4):1108-1116.

     
Vermette, M.S., Schleining, J.A., Greenlee, J.J., Smith, J.D. 2016. Genetic variation of the prion protein gene (PRNP) in alpaca (Vicugna pacos). Gene Reports. 4:213–217.

     

     






  
       
2016 Annual Report

1a. Objectives (from AD-416):

Objective 1: Determine whether goats are a transmission reservoir for ovine scrapie by developing and validating diagnostic methods for detecting goat scrapie. Determine the genetic predisposition and transmission route(s) of goat scrapie. Subobjective 1.1: Improve eradication efforts by developing improved methods for antemortem scrapie diagnosis. Subobjective 1.2: Determine if placenta and milk from goats are potential sources of scrapie to sheep. Objective 2: Develop methods to mitigate infectivity of soil-associated prions by screening soil microbes for potential candidates for bioremediation.

1b. Approach (from AD-416):

Scrapie is a complex and rare disorder affecting outbred farm animals held under a wide variety of husbandry conditions and exposed to an agent for which the transmissible and pathogenic events remain largely unknown. The work described in the research plan is an extension of the previous highly productive studies by this research group, addressing the need for implementation of federal regulations based on the best available science, often in the face of relatively small sample numbers in the natural host. The work includes development of specific management and diagnostic tools and is presented as an integrated series of research objectives. This approach was selected over a hypothesis based approach. After consulting Glass and Hall, the group determined that the work presented in the following plan was best represented by goal statements rather than hypotheses because the work increases the density of data necessary for progress and for support of current and proposed federal regulations. This project addresses only scrapie, the TSE of sheep and goats. Chronic wasting disease (CWD) is the TSE of North America cervids (deer and elk). No live animal work with CWD is included in this project plan since CWD is not endemic in Washington State, the disease appears to be highly communicable, the modes of transmission are unknown, and we do not have suitable biocontainment facilities to conduct CWD studies in large animals.

3. Progress Report:

This is the final report for this project, which ends October 1, 2016. The project included two goal-oriented objectives that fall under National Program 103, Animal Disease, and which address diagnostics, genetics, transmission, and environment as tools in an integrated control and eradication program. Substantial results were realized over the five years of this project period, which are being used by the regulatory agencies to enhance scrapie eradication programs. With regard to Objective 1, significant results were obtained to improve current and develop new diagnostic methods for prion infection. A methodology to measure misfolded prion protein in tissues was developed and used to demonstrate reduced accumulation associated with certain goat genotypes. Several factors were identified that affect the diagnostic performance of rectal mucosa biopsy in sheep and goats. The accuracy of rectal mucosa biopsy was determined for white-tailed deer with chronic wasting disease (CWD), the results alerting regulatory agencies of reduced diagnostic sensitivity when applied during early infection or to a certain deer genotype. With regard to a blood-based diagnostic, research identified the types of peripheral blood cells bearing scrapie prions in domestic sheep and goats, and demonstrated that relatively small amounts of blood should be sufficient for assay development. The surface expression of normal prion protein was characterized for different types of blood cells. The cell types accumulating misfolded prion proteins were identified in a blood-filtering tissue unique to ruminants. As potential alternative forms of a blood-based diagnostic, two biomarkers of infection were discovered using a transgenic mouse model of scrapie and new model cell culture systems permissive to scrapie prions from sheep were developed. Further, multiple factors associated with cellular permissiveness to scrapie infection were identified. To improve detection of prions when levels in tissue are very low—such as occurs in the blood or in the brain during early infection, significant progress was made in adapting two newer methods to small ruminant tissues for ultrasensitive detection. Specifically, serial protein misfolding cyclic amplification (sPMCA) was adapted to detection using white blood cells in sheep, and real-time quaking-induced conversion (RT-QuIC) was adapted to detection using brain samples from goats. With regard to the goal of determining if goats are a transmission reservoir of scrapie, the goat’s placenta and blood were both identified as significant transmission risks to other goats and sheep. Similar progress has been made in demonstrating the transmission risk associated with goat’s milk. With regard to the goal of determining the genetic predisposition of goats to scrapie infection, greatly prolonged scrapie incubation times were identified in goats bearing the prion protein gene polymorphisms GS127, NS146 or QK222. This knowledge impacts the potential use of genetic selection for goats naturally resistant to scrapie and also the application and interpretation of scrapie diagnostics in such goats. Relevant to the current use of genetic selection to manage scrapie infection risk in sheep, results demonstrate no adverse associations of prion protein genotype with the profile of circulating leukocytes—cells critical to a fully functional immune system.

4. Accomplishments

1. A bioassay that differentiates cross-species transmission of prion disease from cervids to sheep. The prevalence of scrapie in U.S. sheep is very low but final eradication may depend on identification and mitigation of novel sources of prions. In contrast to scrapie, the prevalence and geographic range of chronic wasting disease are increasing in deer and elk. While sheep are susceptible to experimental infection with chronic wasting disease prions, the natural occurrence of cross-species transmission is not known due to lack of an assay that differentiates these two types of prion infections in sheep. ARS researchers in Pullman, Washington, in collaboration with researchers at the Canadian Food Inspection Agency have developed a bioassay that differentiates in clinical sheep the brain infection caused by chronic wasting disease from elk and scrapie disease. The bioassay uses two strains of genetically modified mice: a strain modified to express the prion protein of sheep and another strain modified to express the prion protein of elk. The two mouse-strain bioassay thus has the potential to aid surveillance efforts to detect novel transmission events of chronic wasting disease prions from cervids to sheep should this occur in nature.
        
2. Ultrasensitive detection of classical scrapie prions in the brain of goats. Safe, rapid and highly sensitive methods to detect scrapie infection in both sheep and goats are needed to achieve and then maintain scrapie eradication status in the U.S. Current diagnostic assays utilize soft tissues obtained either by biopsy in live animals or by tissue collection after death. Furthermore, the diagnostic sensitivities of current assays are not sufficient for detection in samples with low prion levels, especially during early infection or in blood samples. Real-time quaking-induced conversion (RT-QuIC) is a rapid, ultrasensitive detection method that has been successfully adapted to detection of prions from several host species and in a variety of sample types, including scrapie in the brain of sheep. ARS researchers in Pullman, Washington, in collaboration with researchers at the National Institute for Allergy and Infectious Diseases Rocky Mountain Laboratories in Hamilton, Montana, have now adapted and optimized this method for use with brain samples from goats, including goats bearing prion protein gene polymorphisms not found in sheep. The RT-QuIC methods developed thus provide results for both sheep and goats more rapidly and with at least 10,000-fold greater sensitivity than conventional assays currently in use. This assay thus has the potential to speed and improve detection of infected small ruminants in regular surveillance channels and provides a foundation of knowledge which may facilitate eventually application to a blood-based detection assay.

3. Classical scrapie prions circulating in the blood of sheep associate with specific types of cells. Currently available commercial assays do not possess enough sensitivity to detect small ruminants infected with classical scrapie via a blood sample, even when that blood sample is infectious to other animals. New methods are being developed that provide much higher sensitivity for prions in some tissues, but appear to be inhibited by factors present in blood samples. One approach to improving the performance of both current and experimental methods is to enrich samples with the cells containing prions. ARS researchers in Pullman, Washington, used bioassay to definitively identify which specific types of cells in sheep blood associate with prions. This knowledge supports development of highly sensitive, blood-based assays for regulatory use in the U.S. National Scrapie Eradication Program.

4. Circulating white blood cell profiles in sheep are not associated with variation in prion protein genotype. Genetic selection based on the prion protein gene can be used to reduce the risk of scrapie infection in sheep, but the potential impact of such selection on the immune system has not been evaluated. The function of the prion protein is not completely understood but a potentially deleterious change in a critical part of the immune system—that is, a change in the profile of circulating white blood cells, has been associated with one variant of the prion protein gene found in some cattle. ARS researchers in Pullman, Washington, and Dubois, Idaho, studied ten variants of the prion protein gene in sheep, including the variant gene associated with reduced risk of scrapie infection, but found no alteration to circulating white blood cell profiles. Thus, sheep producers can continue to genetically select to reduce the risk of scrapie infection without concern of adversely affecting this part of the sheep immune system.

5. Potent small molecule inhibitors of scrapie prions identified using a cell culture system of sheep brain cells. There are great needs for development of potent, non-hazardous anti-infective agents to help mitigate prion diseases, including scrapie in sheep and goats. Large libraries of compounds have been screened for inhibitory activity but have generally been performed using rodent-derived cell culture systems infected with rodent- or culture-adapted prion isolates. Recently, a novel small molecule anti-viral agent, DB772, was discovered to have potent inhibitory activity against scrapie prions in cultures of brain cells derived from sheep. ARS researchers in Pullman, Washington, in collaboration with researchers at Washington State University, the University of Georgia, Georgia State University and Augusta University, have now used this sheep-relevant model of scrapie infection to identify eleven additional DB compounds with similar or improved inhibitory potency and lower cell toxicity. The results are an important advance in the rational design of anti-prion agents, providing new insights into the chemical structures critical to inhibitory activity, but also providing new tools with which the mechanisms of prion propagation can be better understood.

5. Significant Activities that Support Special Target Populations:
None.

Review Publications

     

     

     

     





Primate Biol., 3, 47–50, 2016 www.primate-biol.net/3/47/2016/ doi:10.5194/pb-3-47-2016 © Author(s) 2016. CC

Attribution 3.0 License.

Prions

Walter Bodemer German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany Correspondence to: Walter Bodemer (wbodemer@dpz.eu)

Received: 15 June 2016 – Revised: 24 August 2016 – Accepted: 30 August 2016 – Published: 7 September 2016

Abstract.

Prions gained widespread public and scientific interest in the year 2000. At that time, the human neurological Creutzfeldt–Jakob disease (CJD) was known. However, new CJD cases were diagnosed but they could not be ascribed to one of the classical CJD categories i.e. sporadic (sCJD), hereditary or acquired. Hence, they were classified as variant CJD (vCJD). Later on, experimental evidence suggested that vCJD was caused by prions postulated as unique novel infectious agents and, for example, responsible for bovine spongiform encephalopathy (BSE) also known as mad cow disease. The infection of humans by transmission of BSE prions also defined vCJD as a zoonotic disease. Prions, especially those associated with scrapie in sheep had been known for quite some time and misleadingly discussed as a slow virus. Therefore, this enigmatic pathogen and the transmission of this unusual infectious agent was a matter of a controversial scientific debate. An agent without nucleic acid did not follow the current dogma postulating DNA or RNA as inheritable information encoding molecules. Although numerous experimental results clearly demonstrated the infectious capacity of prions in several animal species, a model close to human was not readily available. Therefore, the use of rhesus monkeys (Macaca mulatta) served as a non-human primate model to elucidate prion infection under controlled experimental conditions. Not the least, transmission of BSE, human vCJD, and sCJD prions could be confirmed in our study. Any prion infection concomitant with progression of disease in humans, especially vCJD, could be analyzed only retrospectively and at late stages of disease. In contrast, the prion-infected rhesus monkeys were accessible before and after infection; the progression from early stage to late clinical stages – and eventually death of the animal–could be traced. Because of the phylogenetic proximity to humans, the rhesus monkey was superior to any rodent or other animal model. For these reasons an experimental approach had been conceived by J. Collinge in London and A. Aguzzi in Zurich and performed in a cooperative study with both research groups in the pathology unit of the German Primate Center (DPZ). The study in the DPZ lasted from 2001 until 2012. Our research in the pathology unit provided a temporal monitoring of how an initial prion infection develops eventually into disease; an approach that would have never been possible in humans since the time point of infection with prions from, for example, BSE is always unknown. Telemetry revealed a shift in sleep– wake cycles early on, long before behavioral changes or clinical symptoms appeared. Pathology confirmed nonneuronal tissue as hidden places where prions exist. The rhesus model also allowed first comparative studies of epigenetic modifications on RNA in peripheral blood and brain tissue collected from uninfected and prion infected animals. To conclude, our studies clearly demonstrated that this model is valid since progression to disease is almost identical to human CJD.

Published by Copernicus Publications on behalf of the Deutsches Primatenzentrum GmbH (DPZ).


SNIP...


2 Methods and results

2.1 Animals The reason to perform prion research in rhesus monkeys was to monitor infection and the temporal progression of prion infection in the rhesus monkey. In contrast to studies of human CJD cases, we could decide on the infectious dose. We also could control behavior immediately after prion inoculation and during the rather long time until animals died from the prion infection. Hidden places where prions might exist were found. Even epigenetic modifications on RNA could be detected. Taken together, these experimental approaches depended on animals. Using rhesus monkeys as a model system required thoroughethicreasoningandconsultationwithauthoritiesbefore we actually turned to conduct the experiments. The Number of animals was limited just to fulfill statistical conditions. The individual health status was obtained and health care was provided throughout the study. The animals underwent daily inspection to monitor any changes in health and behavior. The experiments were conceived with the aim of reducing pain, suffering, and harm. Groups of animals were preferred in order to keep them in a social environment. The animals were originally kept in Vienna at Baxter and transferred to the German Primate Center (DPZ) in 2001. J. Collinge, A. Aguzzi, and C. Weissmann were the scientists who recommended this well-controlled prion infection study,and financial support was provided by an EU grant.To ensure statistical significance four groups consisting of four rhesus macaques each were formed: one uninfected control group, one group infected with BSE prions, one with vCJD prions, and one with sCJD prions. Health of animals, infection, and progression to disease was looked at in our pathology department and in cooperation with W. Schulz-Schaeffer at the UMG (University Medicine, Göttingen). Besides, neurologists from the UMG also observed the animals whenever clinical symptoms seemed to appear. This close observation and comparison with human CJD cases demonstrated how close clinical progression of human disease resembles the experimental infection in the non-human primate.

2.2 Infection Infectious prions from brain tissue of one sCJD and one vCJD case (provided by J. Collinge) as well as BSE prions (from a “German”madcow case and provided by W. Schulz Schaeffer) were intraperitoneally administered into the rhesus monkeys.

2.3 Monitoring of behavior and telemetry Early behavioral monitoring was carried out by the ethologists I. Machatschke and J. Dittami from Vienna University. Transmitters were used to record changes in the circadian rhythms. Body temperature, sleep–wake cycles, and activity profiles could be obtained over a time span of 2 years. Up to half a year after infection animals did not show any signs of prion infection. However, after 6 months and persisting for another few months some animals had some disturbances in circadian rhythms which disappeared and then never appeared again(I. Machatschke, personal communication,2006).For a rather long time of about 4–5 years animals seemed to be healthy. But then, almost all animals rapidly progressed to symptoms. Symptoms were highly similar or even identical to those seen in human CJD.

2.4 Pathology Blood and necropsy specimens from the animals served as a valuable source to detect pathologically associated prion protein even in non-neuronal skeletal and cardiac tissue. These “hidden places” of prion pathology and replication were clearly demonstrated and extended our view where prions might spread within an organism. Not only leukocytes and neuronal tissue harbor abnormal prion protein isoforms but also other tissues can propagate prion protein isoforms leading to toxicity, cell degeneration, and eventually transmissible prions (Krasemann et al., 2010, 2013).


SNIP...


3 Conclusion

Most importantly, early signs of an altered circadian rhythm, sleep–wake cycle, and activity and body temperature were recorded in prion-infected animals. This experimental approach would have never been feasible in studies with human CJD cases. After 4–6 years animals developed clinical symptoms highly similar to those typical for CJD. Clinicians confirmed how close the animal model and the human disease matched. Non-neuronal tissue like cardiac muscle and peripheral blood with abnormal, disease-related prion protein were detected in rhesus monkey tissues. 

Molecular changes in RNA from repetitive Alu and BC200 DNA elements were identified and found to be targets of epigenetic editing mechanisms active in prion disease. To conclude, our results with the rhesus monkey model for prion disease proved to be a valid model and increased our knowledge of pathogenic processes that are distinctive to prion disease.


SEE FULL TEXT ;




***at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified.


P-145 Estimating chronic wasting disease resistance in cervids using real time quaking- induced conversion

Nicholas J Haley1, Rachel Rielinqer2, Kristen A Davenport3, W. David Walter4, Katherine I O'Rourke5, Gordon Mitchell6, Juergen A Richt2

1 Department of Microbiology and Immunology, Midwestern University, United States; 2Department of Diagnostic Medicine and Pathobiology, Kansas State University; 3Prion Research Center; Colorado State University; 4U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit; 5Agricultural Research Service, United States Department of Agriculture; 6Canadian Food Inspection Agency, National and OlE Reference Laboratory for Scrapie and CWD
 
In mammalian species, the susceptibility to prion diseases is affected, in part, by the sequence of the host's prion protein (PrP). In sheep, a gradation from scrapie susceptible to resistant has been established both in vivo and in vitro based on the amino acids present at PrP positions 136, 154, and 171, which has led to global breeding programs to reduce the prevalence of scrapie in domestic sheep. In cervids, resistance is commonly characterized as a delayed progression of chronic wasting disease (CWD); at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified. To model the susceptibility of various naturally-occurring and hypothetical cervid PrP alleles in vitro, we compared the amplification rates and efficiency of various CWD isolates in recombinant PrPC using real time quaking-induced conversion. We hypothesized that amplification metrics of these isolates in cervid PrP substrates would correlate to in vivo susceptibility - allowing susceptibility prediction for alleles found at 10 frequency in nature, and that there would be an additive effect of multiple resistant codons in hypothetical alleles. Our studies demonstrate that in vitro amplification metrics predict in vivo susceptibility, and that alleles with multiple codons, each influencing resistance independently, do not necessarily contribute additively to resistance. Importantly, we found that the white-tailed deer 226K substrate exhibited the slowest amplification rate among those evaluated, suggesting that further investigation of this allele and its resistance in vivo are warranted to determine if absolute resistance to CWD is possible.

***at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified.

PRION 2016 CONFERENCE TOKYO

http://prion2016.org/dl/newsletter_03.pdf


Saturday, May 28, 2016

*** Infection and detection of PrPCWD in soil from CWD infected farm in Korea Prion 2016 Tokyo ***

http://chronic-wasting-disease.blogspot.com/2016/05/infection-and-detection-of-prpcwd-in.html


Sunday, December 11, 2016

Clay Components in Soil Dictate Environmental Stability and Bioavailability of Cervid Prions in Mice

http://chronic-wasting-disease.blogspot.com/2016/12/clay-components-in-soil-dictate.html


Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie Experiment 1964

How Did CWD Get Way Down In Medina County, Texas?

Confucius ponders...

Could the Scrapie experiments back around 1964 at Moore Air Force near Mission, Texas, could this area have been ground zero for CWD TSE Prion (besides the CWD cases that have waltzed across the Texas, New Mexico border near WSMR Trans Pecos region since around 2001)?

Epidemiology of Scrapie in the United States 1977

snip...

Scrapie Field Trial Experiments Mission, Texas

A Scrapie Field Trial was developed at Mission, Texas, to provide additional information for the eradication program on the epidemiology of natural scrapie. The Mission Field Trial Station is located on 450 acres of pastureland, part of the former Moore Air Force Base, near Mission, Texas. It was designed to bring previously exposed, and later also unexposed, sheep or goats to the Station and maintain and breed them under close observation for extended periods to determine which animals would develop scrapie and define more closely the natural spread and other epidemiological aspects of the disease.

The 547 previously exposed sheep brought to the Mission Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds. They were purchased as field outbreaks occurred, and represented 21 bloodlines in which scrapie had been diagnosed. Upon arrival at the Station, the sheep were maintained on pasture, with supplemental feeding as necessary. The station was divided into 2 areas: (1) a series of pastures and-pens occupied by male animals only, and (2) a series of pastures and pens occupied by females and young progeny of both sexes. ...

snip...see full text ;




Thursday, June 09, 2016

Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie TSE Prion Experiment 1964

How Did CWD Get Way Down In Medina County, Texas?

Friday, April 22, 2016

*** Texas Scrapie Confirmed in a Hartley County Sheep where CWD was detected in a Mule Deer



Thursday, December 08, 2016

USDA APHIS National Scrapie Eradication Program October 2016 Monthly Report Fiscal Year 2017 atypical NOR-98 Scrapie

http://scrapie-usa.blogspot.com/2016/12/usda-aphis-national-scrapie-eradication.html



***--->Title: Pathological features of chronic wasting disease in reindeer and demonstration of horizontal transmission



Monday, September 05, 2016

Pathological features of chronic wasting disease in reindeer and demonstration of horizontal transmission Major Findings for Norway



Thursday, September 22, 2016

NORWAY DETECTS 5TH CASE OF CHRONIC WASTING DISEASE CWD TSE PRION Skrantesjuke



SUNDAY, OCTOBER 02, 2016

*** What is the risk of a cervid TSE being introduced from Norway into Great Britain? Qualitative Risk Assessment September 2016



Wednesday, September 7, 2016

*** An assessment of the long-term persistence of prion infectivity in aquatic environments



Friday, September 02, 2016

*** Chronic Wasting Disease Drives Population Decline of White-Tailed Deer




Saturday, December 03, 2016


TEXAS CHRONIC WASTING DISEASE CWD TSE PRION UPDATE 35 CASES TO DATE


Wednesday, December 07, 2016


Student Assistant (Temporary) – Chronic Wasting Disease: Texas A&M Veterinary Medical Diagnostic Laboratory


http://chronic-wasting-disease.blogspot.com/2016/12/student-assistant-temporary-chronic.html


Chronic Wasting Disease (CWD) Susceptibility of Several North American Rodents That Are Sympatric with Cervid CWD Epidemics



Thursday, December 15, 2016


Wyoming National Elk Refuge CWD forum update December 8, 2016



http://chronic-wasting-disease.blogspot.com/2016/12/wyoming-national-elk-refuge-cwd-forum.html


 *** WDA 2016 NEW YORK ***

 We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions.

 Student Presentations Session 2

 The species barriers and public health threat of CWD and BSE prions

 Ms. Kristen Davenport1, Dr. Davin Henderson1, Dr. Candace Mathiason1, Dr. Edward Hoover1 1Colorado State University

 Chronic wasting disease (CWD) is spreading rapidly through cervid populations in the USA. Bovine spongiform encephalopathy (BSE, mad cow disease) arose in the 1980s because cattle were fed recycled animal protein. These and other prion diseases are caused by abnormal folding of the normal prion protein (PrP) into a disease causing form (PrPd), which is pathogenic to nervous system cells and can cause subsequent PrP to misfold. CWD spreads among cervids very efficiently, but it has not yet infected humans. On the other hand, BSE was spread only when cattle consumed infected bovine or ovine tissue, but did infect humans and other species. The objective of this research is to understand the role of PrP structure in cross-species infection by CWD and BSE. To study the propensity of each species’ PrP to be induced to misfold by the presence of PrPd from verious species, we have used an in vitro system that permits detection of PrPd in real-time. We measured the conversion efficiency of various combinations of PrPd seeds and PrP substrate combinations. We observed the cross-species behavior of CWD and BSE, in addition to feline-adapted CWD and BSE. We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions. CWD is unique among prion diseases in its rapid spread in natural populations. BSE prions are essentially unaltered upon passage to a new species, while CWD adapts to the new species. This adaptation has consequences for surveillance of humans exposed to CWD.

Wildlife Disease Risk Communication Research Contributes to Wildlife Trust Administration Exploring perceptions about chronic wasting disease risks among wildlife and agriculture professionals and stakeholders

http://www.wda2016.org/uploads/5/8/6/1/58613359/wda_2016_conference_proceedings_low_res.pdf


PRION 2016 TOKYO

Zoonotic Potential of CWD Prions: An Update

Ignazio Cali1, Liuting Qing1, Jue Yuan1, Shenghai Huang2, Diane Kofskey1,3, Nicholas Maurer1, Debbie McKenzie4, Jiri Safar1,3,5, Wenquan Zou1,3,5,6, Pierluigi Gambetti1, Qingzhong Kong1,5,6 1Department of Pathology, 3National Prion Disease Pathology Surveillance Center, 5Department of Neurology, 6National Center for Regenerative Medicine, Case Western Reserve University, Cleveland, OH 44106, USA. 4Department of Biological Sciences and Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada, 2Encore Health Resources, 1331 Lamar St, Houston, TX 77010

Chronic wasting disease (CWD) is a widespread and highly transmissible prion disease in free-ranging and captive cervid species in North America. The zoonotic potential of CWD prions is a serious public health concern, but the susceptibility of human CNS and peripheral organs to CWD prions remains largely unresolved. We reported earlier that peripheral and CNS infections were detected in transgenic mice expressing human PrP129M or PrP129V. Here we will present an update on this project, including evidence for strain dependence and influence of cervid PrP polymorphisms on CWD zoonosis as well as the characteristics of experimental human CWD prions.

PRION 2016 TOKYO In Conjunction with Asia Pacific Prion Symposium 2016 PRION 2016 Tokyo Prion 2016

http://prion2016.org/dl/newsletter_03.pdf

Cervid to human prion transmission

Kong, Qingzhong

Case Western Reserve University, Cleveland, OH, United States

Abstract

Prion disease is transmissible and invariably fatal. Chronic wasting disease (CWD) is the prion disease affecting deer, elk and moose, and it is a widespread and expanding epidemic affecting 22 US States and 2 Canadian provinces so far. CWD poses the most serious zoonotic prion transmission risks in North America because of huge venison consumption (>6 million deer/elk hunted and consumed annually in the USA alone), significant prion infectivity in muscles and other tissues/fluids from CWD-affected cervids, and usually high levels of individual exposure to CWD resulting from consumption of the affected animal among often just family and friends. However, we still do not know whether CWD prions can infect humans in the brain or peripheral tissues or whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no essays to reliably detect CWD infection in humans. We hypothesize that:

(1) The classic CWD prion strain can infect humans at low levels in the brain and peripheral lymphoid tissues;

(2) The cervid-to-human transmission barrier is dependent on the cervid prion strain and influenced by the host (human) prion protein (PrP) primary sequence;

(3) Reliable essays can be established to detect CWD infection in humans;and

(4) CWD transmission to humans has already occurred. We will test these hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in vitro approaches.

Aim 1 will prove that the classical CWD strain may infect humans in brain or peripheral lymphoid tissues at low levels by conducting systemic bioassays in a set of "humanized" Tg mouse lines expressing common human PrP variants using a number of CWD isolates at varying doses and routes. Experimental "human CWD" samples will also be generated for Aim 3.

Aim 2 will test the hypothesis that the cervid-to-human prion transmission barrier is dependent on prion strain and influenced by the host (human) PrP sequence by examining and comparing the transmission efficiency and phenotypes of several atypical/unusual CWD isolates/strains as well as a few prion strains from other species that have adapted to cervid PrP sequence, utilizing the same panel of humanized Tg mouse lines as in Aim 1.

Aim 3 will establish reliable essays for detection and surveillance of CWD infection in humans by examining in details the clinical, pathological, biochemical and in vitro seeding properties of existing and future experimental "human CWD" samples generated from Aims 1-2 and compare them with those of common sporadic human Creutzfeldt-Jakob disease (sCJD) prions.

Aim 4 will attempt to detect clinical CWD-affected human cases by examining a significant number of brain samples from prion-affected human subjects in the USA and Canada who have consumed venison from CWD-endemic areas utilizing the criteria and essays established in Aim 3. The findings from this proposal will greatly advance our understandings on the potential and characteristics of cervid prion transmission in humans, establish reliable essays for CWD zoonosis and potentially discover the first case(s) of CWD infection in humans.

Public Health Relevance There are significant and increasing human exposure to cervid prions because chronic wasting disease (CWD, a widespread and highly infectious prion disease among deer and elk in North America) continues spreading and consumption of venison remains popular, but our understanding on cervid-to-human prion transmission is still very limited, raising public health concerns. This proposal aims to define the zoonotic risks of cervid prions and set up and apply essays to detect CWD zoonosis using mouse models and in vitro methods. The findings will greatly expand our knowledge on the potentials and characteristics of cervid prion transmission in humans, establish reliable essays for such infections and may discover the first case(s) of CWD infection in humans.

Funding Agency Agency National Institute of Health (NIH)

Institute National Institute of Neurological Disorders and Stroke (NINDS)

Type Research Project (R01)

Project # 1R01NS088604-01A1

Application # 9037884

Study Section Cellular and Molecular Biology of Neurodegeneration Study Section (CMND)

Program Officer Wong, May

Project Start 2015-09-30

Project End 2019-07-31

Budget Start 2015-09-30

Budget End 2016-07-31

Support Year 1

Fiscal Year 2015

Total Cost $337,507

Indirect Cost $118,756

Institution

Name Case Western Reserve University

Department Pathology

Type Schools of Medicine

DUNS # 077758407

City Cleveland

State OH

Country United States

Zip Code 44106

http://grantome.com/grant/NIH/R01-NS088604-01A1

Monday, May 02, 2016

*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***

http://chronic-wasting-disease.blogspot.com/2016/05/zoonotic-potential-of-cwd-prions-update.html

Saturday, April 23, 2016

PRION 2016 TOKYO

Saturday, April 23, 2016

 SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016

 Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online

Taylor & Francis

Prion 2016 Animal Prion Disease Workshop Abstracts

WS-01: Prion diseases in animals and zoonotic potential

Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a. Vincent Beringue c. Patricia Aguilar a,

Natalia Fernandez-Borges a. and Alba Marin-Moreno a

"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos, Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT. Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas. France

 Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD) disease in human. To date, BSE agent is the only recognized zoonotic prion. Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that have been circulating for centuries in farmed ruminants there is no apparent epidemiological link between exposure to ruminant products and the occurrence of other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD). However, the zoonotic potential of the diversity of circulating TSE agents has never been systematically assessed. The major issue in experimental assessment of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the biological phenomenon that limits TSE agents’ propagation from a species to another. In the last decade, mice genetically engineered to express normal forms of the human prion protein has proved essential in studying human prions pathogenesis and modeling the capacity of TSEs to cross the human species barrier.

 To assess the zoonotic potential of prions circulating in farmed ruminants, we study their transmission ability in transgenic mice expressing human PrPC (HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC (129Met or 129Val) are used to determine the role of the Met129Val dimorphism in susceptibility/resistance to the different agents.

These transmission experiments confirm the ability of BSE prions to propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be susceptible to BSE in sheep or goat to a greater degree than the BSE agent in cattle and that these agents can convey molecular properties and neuropathological indistinguishable from vCJD. However homozygous 129V mice are resistant to all tested BSE derived prions independently of the originating species suggesting a higher transmission barrier for 129V-PrP variant.

 Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with ef?ciency comparable to that of cattle BSE. While the ef?ciency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.

http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20

 why do we not want to do TSE transmission studies on chimpanzees $

5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.

 snip...

 R. BRADLEY

http://collections.europarchive.org/tna/20080102222950/http://www.bseinquiry.gov.uk/files/yb/1990/09/23001001.pdf


                             


                               
Title: Transmission of scrapie prions to primate after an extended silent incubation period)

 *** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.

 *** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.

 *** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.


SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016

Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online

http://scrapie-usa.blogspot.com/2016/04/scrapie-ws-01-prion-diseases-in-animals.html


O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations

 Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France

 Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.

 *** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,

 ***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),

 ***is the third potentially zoonotic PD (with BSE and L-type BSE),

 ***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.

 ===============

***thus questioning the origin of human sporadic cases***

 ***our findings suggest that possible transmission risk of H-type BSE to sheep and human.



Bioassay will be required to determine whether the PMCA products are infectious to these animals.

  

https://prion2015.files.wordpress.com/2015/05/prion2015abstracts.pdf



Evidence That Transmissible Mink Encephalopathy Results from Feeding Infected Cattle
Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.

snip...

The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...


In Confidence - Perceptions of unconventional slow virus diseases of animals in the USA - APRIL-MAY 1989 - G A H Wells
  
3. Prof. A. Robertson gave a brief account of BSE. The US approach was to accord it a very low profile indeed. Dr. A Thiermann showed the picture in the ''Independent'' with cattle being incinerated and thought this was a fanatical incident to be avoided in the US at all costs. ...
  
”The occurrence of CWD must be viewed against the contest of the locations in which it occurred. It was an incidental and unwelcome complication of the respective wildlife research programmes. Despite it’s subsequent recognition as a new disease of cervids, therefore justifying direct investigation, no specific research funding was forthcoming. The USDA veiwed it as a wildlife problem and consequently not their province!” ...page 26.
  

*** Spraker suggested an interesting explanation for the occurrence of CWD. The deer pens at the Foot Hills Campus were built some 30-40 years ago by a Dr. Bob Davis. At or abut that time, allegedly, some scrapie work was conducted at this site. When deer were introduced to the pens they occupied ground that had previously been occupied by sheep.
  

SPONTANEOUS ATYPICAL BOVINE SPONGIFORM ENCEPHALOPATHY
  
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
  

Saturday, June 25, 2011

Transmissibility of BSE-L and Cattle-Adapted TME Prion Strain to Cynomolgus Macaque

"BSE-L in North America may have existed for decades"

Tuesday, July 26, 2016

*** Atypical Bovine Spongiform Encephalopathy BSE TSE Prion UPDATE JULY 2016 ***

Saturday, July 23, 2016

BOVINE SPONGIFORM ENCEPHALOPATHY BSE TSE PRION SURVEILLANCE, TESTING, AND SRM REMOVAL UNITED STATE OF AMERICA UPDATE JULY 2016
 

Tuesday, September 06, 2016



A comparison of classical and H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism in wild type and EK211 cattle following intracranial inoculation




Friday, August 14, 2015 

*** Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
 



Sunday, August 28, 2016

CONFIDENTIAL

Transmissible Spongiform Encephalopathy TSE Prion and how Politics and Greed by the Industry spread madcow type diseases from species to species and around the globe

TSE PRIONS AKA MAD COW TYPE DISEASE, LIONS AND TIGERS AND BEARS, OH MY!

http://transmissiblespongiformencephalopathy.blogspot.com/2016/08/transmissible-spongiform-encephalopathy.html



Wednesday, December 14, 2016

Diagnosis of Human Prion Disease Using Real-Time Quaking-Induced Conversion Testing of Olfactory Mucosa and Cerebrospinal Fluid Samples

http://creutzfeldt-jakob-disease.blogspot.com/2016/12/diagnosis-of-human-prion-disease-using.html




Terry S. Singeltary Sr.

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