Chronic wasting disease (CWD) in cervids Scientific Opinion EFSA 18 January 2017
Subject: Chronic wasting disease (CWD) in cervids Scientific Opinion EFSA 18 January 2017
Scientific Opinion
Chronic wasting disease (CWD) in cervids
Authors
EFSA Panel on Biological Hazards (BIOHAZ), Antonia Ricci, Ana Allende, Declan Bolton, Marianne Chemaly, Robert Davies, Pablo Salvador Fernández Escámez, Rosina Gironés, Lieve Herman, Kostas Koutsoumanis, Roland Lindqvist, Birgit Nørrung, Lucy Robertson, Moez Sanaa, Panagiotis Skandamis, Emma Snary, Niko Speybroeck, Benno Ter Kuile, John Threlfall, Helene Wahlström, Sylvie Benestad, Dolores Gavier-Widen, Michael W Miller, Giuseppe Ru, Glenn C Telling, Morten Tryland, Angel Ortiz Pelaez, Marion Simmons
First published: 18 January 2017
Full publication history
DOI: 10.2903/j.efsa.2017.4667View/save citation
Cited by: 0 articlesCitation tools
Requestor: European Commission
Question number: EFSA-Q-2016-00387
Panel members: Antonia Ricci, Ana Allende, Declan Bolton, Marianne Chemaly, Robert Davies, Pablo Salvador Fernández Escámez, Rosina Gironés, Lieve Herman, Kostas Koutsoumanis, Roland Lindqvist, Birgit Nørrung, Lucy Robertson, Moez Sanaa, Panagiotis Skandamis, Emma Snary, Niko Speybroeck, Benno Ter Kuile, Giuseppe Ru, Marion Simmons, John Threlfall and Helene Wahlström.
Acknowledgements: The Panel wishes to thank the members of the Working Group on a request for a scientific opinion on Chronic Wasting Disease (CWD) in cervids: Sylvie Benestad, Dolores Gavier-Widen, Michael W Miller, Giuseppe Ru, Marion Simmons, Glenn C Telling and Morten Tryland for the preparatory work on this scientific opinion, and Angel Ortiz Pelaez for the support provided to this scientific opinion. The Panel wishes to acknowledge all organisations and individuals that provided data for this scientific opinion.
Adopted: 2 December 2016
Reproduction of the images listed below is prohibited and permission must be sought directly from the copyright holder:
Figure 1: © USGS; Figure 2: © Norwegian Institute for Nature Research; Figures 3 and 7: © Bernt Johansen (NORUT); Figure 4: © Statistics Norway; Figure 5: © Sim1; Figure 6: © Royal Swedish Academy of Sciences
Correspondence: biohaz@efsa.europa.eu
Abstract
In April and May of 2016, Norway confirmed two cases of chronic wasting disease (CWD) in a wild reindeer and a wild moose, respectively. In the light of this emerging issue, the European Commission requested EFSA to recommend surveillance activities and, if necessary, additional animal health risk-based measures to prevent the introduction of the disease and the spread into/within the EU, specifically Estonia, Finland, Iceland, Latvia, Lithuania, Norway, Poland and Sweden, and considering seven wild, semidomesticated and farmed cervid species (Eurasian tundra reindeer, Finnish (Eurasian) forest reindeer, moose, roe deer, white-tailed deer, red deer and fallow deer). It was also asked to assess any new evidence on possible public health risks related to CWD. A 3-year surveillance system is proposed, differing for farmed and wild or semidomesticated cervids, with a two-stage sampling programme at the farm/geographically based population unit level (random sampling) and individual level (convenience sampling targeting high-risk animals). The current derogations of Commission Implementing Decision (EU) 2016/1918 present a risk of introduction of CWD into the EU. Measures to prevent the spread of CWD within the EU are dependent upon the assumption that the disease is already present; this is currently unknown. The measures listed are intended to contain (limit the geographic extent of a focus) and/or to control (actively stabilise/reduce infection rates in an affected herd or population) the disease where it occurs. With regard to the zoonotic potential, the human species barrier for CWD prions does not appear to be absolute. These prions are present in the skeletal muscle and other edible tissues, so humans may consume infected material in enzootic areas. Epidemiological investigations carried out to date make no association between the occurrence of sporadic Creutzfeldt–Jakob disease in humans and exposure to CWD prions.
Summary
In April and May of 2016, Norway confirmed two cases of chronic wasting disease (CWD) in a wild reindeer and a wild moose, respectively. This was the first time CWD had been detected in Europe and the first natural case in reindeer in the world. In the light of the sensitivity of this emerging issue, the European Food Safety Authority (EFSA) was asked by the European Commission to deliver its scientific opinion by 31 December 2016 on the following Terms of Reference (ToRs): (1) to provide recommendations on surveillance of cervid populations at the country level aimed at detecting CWD and/or estimating the prevalence of CWD in Norway, Sweden, Finland, Iceland, Estonia, Latvia and Poland, which are the European Union (EU) and European Economic Area (EEA) countries with reindeer and/or moose populations, depending on the level of prevalence which is wished to be detected; (2) has new evidence become available with regard to possible public health risks due to the occurrence of CWD in cervids since the publication of the 2011 joint EFSA/ECDC opinion? Does the natural exposure of consumers to cervid products originating from regions where CWD cases are detected represent a risk for public health? (3) EFSA is asked to recommend, if necessary, additional animal health risk-based measures to prevent the introduction of CWD into the EU cervid populations and to prevent its spread within the EU.
It was agreed with the requestor to also include Lithuania in the mandate, and to consider the following seven wild, semidomesticated and farmed cervids, namely Eurasian tundra reindeer (Rangifer tarandus tarandus), Finnish (Eurasian) forest reindeer (Rangifer tarandus fennicus), moose (Eurasian/European elk) (Alces alces alces), roe deer (Capreolus capreolus), white-tailed deer (Odocoileus virginianus), red deer (Cervus elaphus) and fallow deer (Dama dama).
The data used in this assessment have been sourced via different literature searches, looking at the new evidence from experimental studies examining the transmissibility of transmissible spongiform encephalopathies (TSE) agents to humans, as well as the epidemiology, surveillance and control of CWD. The figures on wild and hunted population abundance were obtained from different sources and represent various methodologies used for census and estimates. Surveillance data in Europe in 2015 have been extracted from annual reports submitted by the Member States (MS) and from the background information provided by the European Commission and included in the mandate.
It was agreed, due to limited time and resources, to carry out a qualitative evaluation by means of literature reviews based on the knowledge and expertise of the Working Group (WG) members. The experts in the WG selected relevant references starting from review papers, books chapters, non-peer-review papers known by the experts themselves or retrieved through non-systematic searches until the information of the subject was considered sufficient to undertake the assessment by the WG. The literature search was used to support the expert review of these areas, and additional scientific information known by the experts was also considered in the assessment.
The surveillance system proposed for the countries concerned is based on the experience of CWD surveillance in North America and the knowledge of the different structures and management systems of the cervid populations of some of the countries concerned, in particular Norway and Sweden. The aims of the proposed surveillance system are to detect disease in countries where CWD has not yet been detected using a predefined design prevalence and to estimate prevalence in areas where disease has been detected. It is intended to overcome the shortcomings highlighted in the evaluation of the previous surveillance programme implemented in Europe 2006–2010. A two-stage sampling programme is proposed based on the application of random sampling at the first stage (for wild/semidomesticated cervids the ‘primary sampling units’ (PSU) will correspond to geographical areas containing cervid populations, whereas for farmed cervids they will correspond to farms) and the application of convenience sampling of high-risk animals within PSU (found dead, hunted or slaughtered animals considered not fit for human consumption, road/predator kills and animals killed because they are sick or in poor body condition and not fit for human consumption) of any of the selected species at the second stage.
With regard to the public health risks, there is currently no experimental model that encompasses all the potential host and agent variability required to assess zoonotic potential directly for any animal prion disease, including CWD. Although CWD has been experimentally transmitted to squirrel monkeys; in vivo transmission of CWD to other animal models including macaques and humanised mice has not yet been reported. CWD strains, their prevalence, host range and zoonotic potential remain incompletely understood. All currently available data pertaining to host range and human risk are derived from isolates obtained from North American cervid species, but preliminary evidence from the Norwegian CWD cases raises the possibility that European and North American isolates are different from each other.
There is no evidence of an absolute species barrier between CWD-affected cervids and humans. CWD prions are present in the skeletal muscle and other edible tissues, which means that humans may consume infected material in enzootic areas. However, from the epidemiological investigations carried out to date, no association has been made between the occurrence of sporadic Creutzfeldt–Jakob disease (sCJD) in humans and exposure to CWD.
Since it was concluded that the most likely pathway of introduction of CWD into the EU is the movement of live cervids, the current derogations of Article 2.2 of the Commission Implementing Decision (EU) 2016/1918 present a risk of introduction of CWD into the EU. The probability of introduction of CWD into and spread within the EU associated with the movement of live cervids for direct slaughter is considered to be lower than situations in which live animals are translocated for other purposes. Minimising movements of live cervids would reduce the probability of introduction of CWD into the EU. The use of natural cervid urine lures is considered to increase the probability of introduction of CWD into the EU. Compliance with recommendations included in awareness campaigns targeting both local Norwegian hunters, and hunters visiting Norway from (and returning to) other countries, would reduce the probability of introduction of CWD into the EU.
Measures to prevent the spread of CWD within the EU are dependent upon the assumption that the disease is already present in some part of the EU territory. At the time of writing this opinion, this is unknown. The uncertainties associated with the limited knowledge of the situation of CWD in the countries concerned could render any of the recommended measures inadequate or insufficient. Moreover, strategies to prevent the introduction and/or the spread of CWD must be based on a combination of measures.
A list of measures has been included. Some aim to reduce animal-to-animal contact and lower population densities; others relate to increasing the disease awareness among stakeholders, reducing environmental contamination and developing contingency plans, including quarantine and other measures in infected and management premises/areas. Specific prohibitions within Norway, affecting silage, feed and lichen to prevent the spread of CWD, have been mentioned.
Additional activities have been recommended, such as reviewing the design of the surveillance system after 1 year of implementation, conducting a risk assessment to estimate the likelihood of introduction of CWD into the EU, collecting data on the cervid populations in Europe, implementing an individual identification system and record-keeping of farmed and semidomesticated cervids together with an ad hoc data collection system for surveillance. Any positive case detected through surveillance should be genotyped and characterised by strain typing, with representative material archived for future reference. It is also recommended that all or a representative subset of cervids tested negative by surveillance are genotyped. Consideration is given to implementing surveillance programmes in other MS.
1 Introduction
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4.2 Answer to Term of Reference 2
There are many factors that influence the ability of any TSE agent to infect a host, regardless of whether the infection occurs across a species barrier. Currently, there is no experimental model that encompasses all the potential host and agent variability to directly assess zoonotic potential for any animal prion disease, including CWD.
Although CWD has been transmitted to squirrel monkeys, in vivo transmission of CWD to other animal models, including macaques and humanised mice, has not yet been reported.
New evidence shows that in vitro amplified CWD can convert human PrP by PMCA. Experiments using RT-QuIC also suggest that at the level of protein–protein interactions the molecular barrier preventing transmission of CWD to humans may be less robust than previously thought.
Based on the previous two bullet points, there is no evidence of an absolute species barrier between CWD-affected cervids and humans.
CWD strains, their prevalence, host range and zoonotic potential remain incompletely understood. All currently available data pertaining to host range and human risk are derived from isolates from cases of CWD identified in North American cervid species. Preliminary evidence from the Norwegian CWD cases raises the possibility that European and North American isolates are different.
CWD prions are present in the skeletal muscle and other edible tissues which means that humans may consume infected material in enzootic areas.
There are no data on the effective infectious ‘dose’ of CWD for humans, or how that might vary by agent strain/host species. The level of oral exposure is largely determined by the prevalence of animal TSE and by the amount of infectivity in animal tissues entering the food chain. The latter is reduced for BSE and scrapie by the specified risk materials (SRM) measures, but such measures are not mandatory for cervids consumed in North America.
From the epidemiological investigations carried out to date, no association has been made between the occurrence of sCJD in humans and exposure to CWD. Surveillance of sCJD indicates that the mean overall annual mortality rates are relatively consistent at 1–1.5 cases per million in both Europe and North America.
>>> From the epidemiological investigations carried out to date, no association has been made between the occurrence of sCJD in humans and exposure to CWD. Surveillance of sCJD indicates that the mean overall annual mortality rates are relatively consistent at 1–1.5 cases per million in both Europe and North America. <<<
LAUGH OUT LOUD LOL!
cwd zoonosis, and the science there from of late...as follows;
*** 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
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
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
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.
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.
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R. BRADLEY
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
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.
LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.
PRION 2015 CONFERENCE FT. COLLINS CWD RISK FACTORS TO HUMANS
*** LATE-BREAKING ABSTRACTS PRION 2015 CONFERENCE ***
O18
Zoonotic Potential of CWD Prions
Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1, Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy, 3Encore Health Resources, Houston, Texas, USA
*** These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.
==================
***These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.***
==================
P.105: RT-QuIC models trans-species prion transmission
Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover Prion Research Center; Colorado State University; Fort Collins, CO USA
Conversely, FSE maintained sufficient BSE characteristics to more efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was competent for conversion by CWD and fCWD.
***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.
================
***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.***
================
*** PRICE OF CWD TSE PRION POKER GOES UP 2014 ***
Transmissible Spongiform Encephalopathy TSE PRION update January 2, 2014
*** chronic wasting disease, there was no absolute barrier to conversion of the human prion protein.
*** Furthermore, the form of human PrPres produced in this in vitro assay when seeded with CWD, resembles that found in the most common human prion disease, namely sCJD of the MM1 subtype.
***********CJD REPORT 1994 increased risk for consumption of veal and venison and lamb***********
CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL REPORT AUGUST 1994
Consumption of venison and veal was much less widespread among both cases and controls. For both of these meats there was evidence of a trend with increasing frequency of consumption being associated with increasing risk of CJD. (not nvCJD, but sporadic CJD...tss)
These associations were largely unchanged when attention was restricted to pairs with data obtained from relatives. ...
Table 9 presents the results of an analysis of these data.
There is STRONG evidence of an association between ‘’regular’’ veal eating and risk of CJD (p = .0.01).
Individuals reported to eat veal on average at least once a year appear to be at 13 TIMES THE RISK of individuals who have never eaten veal.
There is, however, a very wide confidence interval around this estimate. There is no strong evidence that eating veal less than once per year is associated with increased risk of CJD (p = 0.51).
The association between venison eating and risk of CJD shows similar pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK OF CJD (p = 0.04).
There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY OF LAMB EATING (p = 0.02).
The evidence for such an association between beef eating and CJD is weaker (p = 0.14). When only controls for whom a relative was interviewed are included, this evidence becomes a little STRONGER (p = 0.08).
snip...
It was found that when veal was included in the model with another exposure, the association between veal and CJD remained statistically significant (p = < 0.05 for all exposures), while the other exposures ceased to be statistically significant (p = > 0.05).
snip...
In conclusion, an analysis of dietary histories revealed statistical associations between various meats/animal products and INCREASED RISK OF CJD. When some account was taken of possible confounding, the association between VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS STATISTICALLY. ...
snip...
In the study in the USA, a range of foodstuffs were associated with an increased risk of CJD, including liver consumption which was associated with an apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3 studies in relation to this particular dietary factor, the risk of liver consumption became non-significant with an odds ratio of 1.2 (PERSONAL COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)
snip...see full report ;
CJD9/10022
October 1994
Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge Spencers Lane BerksWell Coventry CV7 7BZ
Dear Mr Elmhirst,
CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT
Thank you for your recent letter concerning the publication of the third annual report from the CJD Surveillance Unit. I am sorry that you are dissatisfied with the way in which this report was published.
The Surveillance Unit is a completely independant outside body and the Department of Health is committed to publishing their reports as soon as they become available. In the circumstances it is not the practice to circulate the report for comment since the findings of the report would not be amended. In future we can ensure that the British Deer Farmers Association receives a copy of the report in advance of publication.
The Chief Medical Officer has undertaken to keep the public fully informed of the results of any research in respect of CJD. This report was entirely the work of the unit and was produced completely independantly of the the Department.
The statistical results reqarding the consumption of venison was put into perspective in the body of the report and was not mentioned at all in the press release. Media attention regarding this report was low key but gave a realistic presentation of the statistical findings of the Unit. This approach to publication was successful in that consumption of venison was highlighted only once by the media ie. in the News at one television proqramme.
I believe that a further statement about the report, or indeed statistical links between CJD and consumption of venison, would increase, and quite possibly give damaging credence, to the whole issue. From the low key media reports of which I am aware it seems unlikely that venison consumption will suffer adversely, if at all.
http://web.archive.org/web/20030511010117/http://www.bseinquiry.gov.uk/files/yb/1994/10/00003001.pdf
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
*** PRION 2014 CONFERENCE CHRONIC WASTING DISEASE CWD
*** PPo3-7: Prion Transmission from Cervids to Humans is Strain-dependent
*** Here we report that a human prion strain that had adopted the cervid prion protein (PrP) sequence through passage in cervidized transgenic mice efficiently infected transgenic mice expressing human PrP,
*** indicating that the species barrier from cervid to humans is prion strain-dependent and humans can be vulnerable to novel cervid prion strains.
PPo2-27:
Generation of a Novel form of Human PrPSc by Inter-species Transmission of Cervid Prions
*** Our findings suggest that CWD prions have the capability to infect humans, and that this ability depends on CWD strain adaptation, implying that the risk for human health progressively increases with the spread of CWD among cervids.
PPo2-7:
Biochemical and Biophysical Characterization of Different CWD Isolates
*** The data presented here substantiate and expand previous reports on the existence of different CWD strains.
Envt.07:
Pathological Prion Protein (PrPTSE) in Skeletal Muscles of Farmed and Free Ranging White-Tailed Deer Infected with Chronic Wasting Disease
***The presence and seeding activity of PrPTSE in skeletal muscle from CWD-infected cervids suggests prevention of such tissue in the human diet as a precautionary measure for food safety, pending on further clarification of whether CWD may be transmissible to humans.
>>>CHRONIC WASTING DISEASE , THERE WAS NO ABSOLUTE BARRIER TO CONVERSION OF THE HUMAN PRION PROTEIN<<<
*** PRICE OF CWD TSE PRION POKER GOES UP 2014 ***
Transmissible Spongiform Encephalopathy TSE PRION update January 2, 2014
Wednesday, January 01, 2014
Molecular Barriers to Zoonotic Transmission of Prions
*** chronic wasting disease, there was no absolute barrier to conversion of the human prion protein.
*** Furthermore, the form of human PrPres produced in this in vitro assay when seeded with CWD, resembles that found in the most common human prion disease, namely sCJD of the MM1 subtype.
*** now, let’s see what the authors said about this casual link, personal communications years ago, and then the latest on the zoonotic potential from CWD to humans from the TOKYO PRION 2016 CONFERENCE.
see where it is stated NO STRONG evidence. so, does this mean there IS casual evidence ???? “Our conclusion stating that we found no strong evidence of CWD transmission to humans”
From: TSS (216-119-163-189.ipset45.wt.net)
Subject: CWD aka MAD DEER/ELK TO HUMANS ???
Date: September 30, 2002 at 7:06 am PST
From: "Belay, Ermias"
To: Cc: "Race, Richard (NIH)" ; ; "Belay, Ermias"
Sent: Monday, September 30, 2002 9:22 AM
Subject: RE: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS
Dear Sir/Madam,
In the Archives of Neurology you quoted (the abstract of which was attached to your email), we did not say CWD in humans will present like variant CJD. That assumption would be wrong. I encourage you to read the whole article and call me if you have questions or need more clarification (phone: 404-639-3091). Also, we do not claim that "no-one has ever been infected with prion disease from eating venison." Our conclusion stating that we found no strong evidence of CWD transmission to humans in the article you quoted or in any other forum is limited to the patients we investigated.
Ermias Belay, M.D. Centers for Disease Control and Prevention
-----Original Message-----
From: Sent: Sunday, September 29, 2002 10:15 AM
Subject: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS
Sunday, November 10, 2002 6:26 PM ......snip........end..............TSS
Thursday, April 03, 2008
A prion disease of cervids: Chronic wasting disease 2008 1: Vet Res. 2008 Apr 3;39(4):41 A prion disease of cervids: Chronic wasting disease Sigurdson CJ.
snip...
*** twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center***,
snip... full text ;
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
THIS SHOULD BE VERY IMPORTANT TO ALL CATTLE RANCHERS, BEEF PRODUCERS, AND OR DAIRY FARMERS
2016 Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
V. Use in animal feed of material from deer and elk NOT considered at high risk for CWD FDA continues to consider materials from deer and elk NOT considered at high risk for CWD to be acceptable for use in NON-RUMINANT animal feeds in accordance with current agency regulations, 21 CFR 589.2000. Deer and elk not considered at high risk include: (1) deer and elk from areas not declared by State officials to be endemic for CWD and/or to be CWD eradication zones; and (2) deer and elk that were not at some time during the 60-month period immediately before the time of slaughter in a captive herd that contained a CWD-positive animal.
SNIP...
Greetings again FDA and Mr. Pritchett et al,
MY comments and source reference of sound science on this very important issue are as follows ;
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
I kindly wish to once again submit to Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed.
Thank you kindly for allowing me to comment again, ...and again...and again, on a topic so important, why it is ‘NON-BINDING’ is beyond me.
this should have been finalized and made ‘BINDING’ or MANDATORY OVER A DECADE AGO.
but here lay the problem, once made ‘BINDING’ or ‘MANDATORY’, it is still nothing but ink on paper.
we have had a mad cow feed ban in place since August 1997, and since then, literally 100s of millions of pounds BANNED MAD COW FEED has been sent out to commerce and fed out (see reference materials).
ENFORCEMENT OF SAID BINDING REGULATIONS HAS FAILED US TOO MANY TIMES.
so, in my opinion, any non-binding or voluntary regulations will not work, and to state further, ‘BINDING’ or MANDATORY regulations will not work unless enforced.
with that said, we know that Chronic Wasting Disease CWD TSE Prion easily transmits to other cervid through the oral route.
the old transmission studies of BSE TSE floored scientist once they figured out what they had, and please don’t forget about those mink that were fed 95%+ dead stock downer cow, that all came down with TME. please see ;
It is clear that the designing scientists must also have shared Mr Bradleys surprise at the results because all the dose levels right down to 1 gram triggered infection.
it is clear that the designing scientists must have also shared Mr Bradleys surprise at the results because all the dose levels right down to 1 gram triggered infection.
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...
To further complicate things, we now know that science has shown that plants and vegetables can uptake the TSE Prion, and that the Scrapie agent can still be infectious from soil 16 years later. a frightening thought with the CWD running rampant now in North America (please see source reference materials below).
IF we don’t do this, we have failed, and the TSE Prion agent will continue to spread, as it is doing as we speak.
I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids, as well as non-ruminants such as cats and dogs as well, as soon as possible for the following reasons...
Sunday, March 20, 2016
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
Singeltary previous submission to DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability
DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability Fri, 16 May 2003 11:47:37 0500 EMC 1 Terry S. Singeltary Sr. Vol #: 1
Date: Fri, 16 May 2003 11:47:37 0500 EMC 1 Terry S. Singeltary Sr. Vol #: 1
MARCH 1, 2011
UPDATED CORRESPONDENCE FROM AUTHORS OF THIS STUDY I.E. COLBY, PRUSINER ET AL, ABOUT MY CONCERNS OF THE DISCREPANCY BETWEEN THEIR FIGURES AND MY FIGURES OF THE STUDIES ON CWD TRANSMISSION TO CATTLE ;
----- Original Message ----- From: David Colby To: flounder9@verizon.net
Cc: stanley@XXXXXXXX Sent: Tuesday, March 01, 2011 8:25 AM
Subject: Re: FW: re-Prions
David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations
Dear Terry Singeltary, Thank you for your correspondence regarding the review article Stanley Prusiner and I recently wrote for Cold Spring Harbor Perspectives. Dr. Prusiner asked that I reply to your message due to his busy schedule. We agree that the transmission of CWD prions to beef livestock would be a troubling development and assessing that risk is important. In our article, we cite a peer-reviewed publication reporting confirmed cases of laboratory transmission based on stringent criteria. The less stringent criteria for transmission described in the abstract you refer to lead to the discrepancy between your numbers and ours and thus the interpretation of the transmission rate. We stand by our assessment of the literature--namely that the transmission rate of CWD to bovines appears relatively low, but we recognize that even a low transmission rate could have important implications for public health and we thank you for bringing attention to this matter.
Warm Regards, David Colby --
David Colby, PhDAssistant ProfessorDepartment of Chemical EngineeringUniversity of Delaware
====================END...TSS==============
SNIP...SEE FULL TEXT ;
UPDATED DATA ON 2ND CWD STRAIN
Wednesday, September 08, 2010 CWD PRION CONGRESS SEPTEMBER 8-11 2010
Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies Location: Virus and Prion Diseases of Livestock
Title: TRANSMISSION OF CHRONIC WASTING DISEASE AGENT OF MULE DEER (CWD**MD) TO SUFFOLK SHEEP BY INTRACEREBRAL ROUTE
Authors Hamir, Amirali Kunkle, Robert Cutlip, Randall - ARS RETIRED Miller, Janice - ARS RETIRED Williams, Elizabeth - UNIVERSITY OF WYOMING Richt, Juergen Submitted to: European Society of Veterinary Pathology
Publication Type: Abstract Publication Acceptance Date: June 5, 2006 Publication Date: August 31, 2006
Citation: Hamir, A., Kunkle, R., Cutlip, R., Miller, J., Williams, E., Richt, J. 2006.
Transmission of chronic wasting disease agent of mule deer (CWD**md) to Suffolk sheep by intracerebral route [abstract]. European Society of Veterinary Pathology 24th Annual Meeting. Paper No. P63. p. 171-172.
Technical Abstract: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that has been identified in captive and free-ranging cervids in the U.S. since 1967. To determine the transmissibility of CWD to sheep, 8 Suffolk lambs [4 QQ and 4 QR at codon 171 of prion protein (PRNP) gene] were inoculated intracerebrally with a pooled brain suspension from 28 mule deer naturally affected with CWD (CWD**md). Two other lambs (1 QQ and 1 QR at codon 171 of the PRNP gene) were kept as non-inoculated controls. Within 36 months post inoculation (MPI), 2 animals became sick and were euthanized. Only 1 sheep (euthanized at 35 MPI) showed clinical signs that were consistent with those described for scrapie. Microscopic lesions of spongiform encephalopathy (SE) were only seen in the sheep with the clinical signs of TSE and its tissues were positive for the abnormal prion protein (PrP**res) by immunohistochemistry and Western blot. Between 36 and 60 MPI, 3 other sheep were euthanized because of conditions unrelated to TSE. The remaining 3 sheep remained non-clinical at the termination of the study (72 MPI) and were euthanized at that time. One of the 3 animals revealed SE and its tissues were positive for PrP**res. Both sheep positive for PrP**res were homozygous QQ at codon 171. Retrospective examination of the PRNP genotype of the 2 TSE-positive animals revealed that the sheep with clinical prion disease (euthanized at 35 MPI) was heterozygous (AV) and the sheep with the sub-clinical disease (euthanized at 72 MPI) was homozygous (AA) at codon 136 of the PRNP. These findings demonstrate that transmission of the CWD**md agent to sheep via the intracerebral route is possible. Interestingly, the host genotype may play a significant part in successful transmission and incubation period of CWD**md.
Transmission of chronic wasting disease of mule deer to Suffolk sheep following intracerebral inoculation
Amir N. Hamir,1 Robert A. Kunkle, Randall C. Cutlip, Janice M. Miller, Elizabeth S. Williams, Juergen A. Richt
Abstract. To determine the transmissibility of chronic wasting disease (CWD) to sheep, 8 Suffolk lambs of various prion protein genotypes (4 ARQ/ARR, 3 ARQ/ARQ, 1 ARQ/VRQ at codons 136, 154, and 171, respectively) were inoculated intracerebrally with brain suspension from mule deer with CWD (CWDmd). Two other lambs were kept as noninoculated controls. Within 36 months postinoculation (MPI), 2 inoculated animals became sick and were euthanized. Only 1 sheep (euthanized at 35 MPI) showed clinical signs that were consistent with those described for scrapie. Microscopic lesions of spongiform encephalopathy (SE) were only seen in this sheep, and its tissues were determined to be positive for the abnormal prion protein (PrPres) by immunohistochemistry and Western blot. Three other inoculated sheep were euthanized (36 to 60 MPI) because of conditions unrelated to TSE. The 3 remaining inoculated sheep and the 2 control sheep did not have clinical signs of disease at the termination of the study (72 MPI) and were euthanized. Of the 3 remaining inoculated sheep, 1 was found to have SE, and its tissues were positive for PrPres. The sheep with clinical prion disease (euthanized at 35 MPI) was of the heterozygous genotype (ARQ/VRQ), and the sheep with subclinical disease (euthanized at 72 MPH) was of the homozygous ARQ/ARQ genotype. These findings demonstrate that transmission of the CWDmd agent to sheep via the intracerebral route is possible. Interestingly, the host genotype may play a notable part in successful transmission and incubation period of CWDmd. snip...
Thus far, among domestic animals, CWDmd has been transmitted by the intracerebral route to a goat18 and cattle.5–7 The present findings demonstrate that it is also possible to transmit CWDmd agent to sheep via the intracerebral route. However, the only sheep to develop clinical TSE within 35 MPI was genotypically AV at PRNP codon 136, suggesting that host genotype may play a notable part in successful transmission of the disease in this species. Although in Suffolk sheep the AV variant at codon 136 is very rare,17 selective breeding of Suffolk sheep with this codon has begun in the hope of testing this differential susceptibility hypothesis in a future study of CWDmd transmission to sheep. Key words: Chronic wasting disease; immunohistochemistry; intracerebral transmission; prion protein; sheep; spongiform encephalopathy.
Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies Location: Virus and Prion Diseases of Livestock
Title: EXPERIMENTAL SECOND PASSAGE OF CHRONIC WASTING DISEASE (CWD(MULE DEER)) AGENT TO CATTLE
Authors Hamir, Amirali Kunkle, Robert Miller, Janice - ARS RETIRED Greenlee, Justin Richt, Juergen Submitted to: Journal of Comparative Pathology Publication Type: Peer Reviewed Journal Publication Acceptance Date: July 25, 2005 Publication Date: January 1, 2006 Citation: Hamir, A.N., Kunkle, R.A., Miller, J.M., Greenlee, J.J., Richt, J.A. 2006.
Experimental second passage of chronic wasting disease (CWD(mule deer)) agent to cattle. Journal of Comparative Pathology. 134(1):63-69. Interpretive Summary: To compare the findings of experimental first and second passage of chronic wasting disease (CWD) in cattle, 6 calves were inoculated into the brain with CWD-mule deer agent previously (first) passaged in cattle. Two other uninoculated calves served as controls. Beginning 10-12 months post inoculation (PI), all inoculates lost appetite and weight. Five animals subsequently developed clinical signs of central nervous system (CNS) abnormality. By 16.5 months PI, all cattle had been euthanized because of poor prognosis. None of the animals showed microscopic lesions of spongiform encephalopathy (SE) but the CWD agent was detected in their CNS tissues by 2 laboratory techniques (IHC and WB). These findings demonstrate that inoculated cattle amplify CWD agent but also develop clinical CNS signs without manifestation of microscopic lesions of SE. This situation has also been shown to occur following inoculation of cattle with another TSE agent, namely, sheep scrapie. The current study confirms previous work that indicates that the diagnostic tests currently used for confirmation of bovine spongiform encephalopathy (BSE) in the U.S. would detect CWD in cattle, should it occur naturally. Furthermore, it raises the possibility of distinguishing CWD from BSE in cattle due to the absence of microscopic lesions and a unique multifocal distribution of PrPres, as demonstrated by IHC, which in this study, appears to be more sensitive than the WB.
Technical Abstract: To compare clinicopathological findings of first and second passage of chronic wasting disease (CWD) in cattle, a group of calves (n=6) were intracerebrally inoculated with CWD-mule deer agent previously (first) passaged in cattle. Two other uninoculated calves served as controls. Beginning 10-12 months post inoculation (PI), all inoculates lost appetite and lost weight. Five animals subsequently developed clinical signs of central nervous system (CNS) abnormality. By 16.5 months PI, all cattle had been euthanized because of poor prognosis. None of the animals showed microscopic lesions of spongiform encephalopathy (SE) but PrPres was detected in their CNS tissues by immunohistochemistry (IHC) and Western blot (WB) techniques. These findings demonstrate that intracerebrally inoculated cattle not only amplify CWD PrPres but also develop clinical CNS signs without manifestation of morphologic lesions of SE. This situation has also been shown to occur following inoculation of cattle with another TSE agent, scrapie. The current study confirms previous work that indicates the diagnostic techniques currently used for confirmation of bovine spongiform encephalopathy (BSE) in the U.S. would detect CWD in cattle, should it occur naturally. Furthermore, it raises the possibility of distinguishing CWD from BSE in cattle due to the absence of neuropathologic lesions and a unique multifocal distribution of PrPres, as demonstrated by IHC, which in this study, appears to be more sensitive than the WB.http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=178318
***These findings demonstrate that inoculated cattle amplify CWD agent but also develop clinical CNS signs without manifestation of microscopic lesions of SE.*** Wednesday, September 21, 2011 Evidence for distinct CWD strains in experimental CWD in ferrets
Wednesday, October 12, 2011
White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation
Wednesday, July 06, 2011
Swine Are Susceptible to Chronic Wasting Disease by Intracerebral Inoculation http://chronic-wasting-disease.blogspot.com/2011/07/swine-are-susceptible-to-chronic.html
WS-02
Scrapie in swine: A diagnostic challenge
Justin J Greenlee1, Robert A Kunkle1, Jodi D Smith1, Heather W. Greenlee2
1National Animal Disease Center, US Dept. of Agriculture, Agricultural Research Service, United States; 2Iowa State University College of Veterinary Medicine A naturally occurring prion disease has not been recognized in swine, but the agent of bovine spongiform encephalopathy does transmit to swine by experimental routes. Swine are thought to have a robust species barrier when exposed to the naturally occurring prion diseases of other species, but the susceptibility of swine to the agent of sheep scrapie has not been thoroughly tested. Since swine can be fed rations containing ruminant derived components in the United States and many other countries, we conducted this experiment to test the susceptibility of swine to U.S. scrapie isolates by intracranial and oral inoculation. Scrapie inoculum was a pooled 10% (w/v) homogenate derived from the brains of clinically ill sheep from the 4th passage of a serial passage study of the U.S scrapie agent (No. 13-7) through susceptible sheep that were homozygous ARQ at prion protein residues 136, 154, and 171, respectively. Pigs were inoculated intracranially (n=19) with a single 0.75 ml dose or orally (n=24) with 15 ml repeated on 4 consecutive days. Necropsies were done on a subset of animals at approximately six months post inoculation (PI), at the time the pigs were expected to reach market weight. Remaining pigs were maintained and monitored for clinical signs of TSE until study termination at 80 months PI or when removed due to intercurrent disease (primarily lameness). Brain samples were examined by immunohistochemistry (IHC), western blot (WB), and enzyme-linked immunosorbent assay (ELISA). Brain tissue from a subset of pigs in each inoculation group was used for bioassay in mice expressing porcine PRNP.
At six-months PI, no evidence of scrapie infection was noted by any diagnostic method. However, at 51 months of incubation or greater, 5 animals were positive by one or more methods: IHC (n=4), WB (n=3), or ELISA (n=5). Interestingly, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study).
Swine inoculated with the agent of scrapie by the intracranial and oral routes do not accumulate abnormal prion protein (PrPSc) to a level detectable by IHC or WB by the time they reach typical market age and weight. However, strong support for the fact that swine are potential hosts for the agent of scrapie comes from positive bioassay from both intracranially and orally inoculated pigs and multiple diagnostic methods demonstrating abnormal prion protein in intracranially inoculated pigs with long incubation times.
Curriculum Vitae
Dr. Greenlee is Research Veterinary Medical Officer in the Virus and Prion Research Unit at the National Animal Disease Center, US Department of Agriculture, Agricultural Research Service. He applies his specialty in veterinary anatomic pathology to focused research on the intra- and interspecies transmission of prion diseases in livestock and the development of antemortem diagnostic assays for prion diseases. In addition, knockout and transgenic mouse models are used to complement ongoing experiments in livestock species. Dr. Greenlee has publications in a number of topic areas including prion agent decontamination, effects of PRNP genotype on susceptibility to the agent of sheep scrapie, characterization of US scrapie strains, transmission of chronic wasting disease to cervids and cattle, features of H-BSE associated with the E211 K polymorphism, and the development of retinal assessment for antemortem screening for prion diseases in sheep and cattle. Dr. Greenlee obtained his DVM degree and completed the PhD/residency program in Veterinary Pathology at Iowa State University. He is a Diplomate of the American College of Veterinary Pathologists.
***In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006). It is not known how susceptible humans are to CWD but given that the prion can be present in muscle, it is likely that humans have been exposed to the agent via consumption of venison (Sigurdson, 2008). Initial experimental research, however, suggests that human susceptibility to CWD is low and there may be a robust species barrier for CWD transmission to humans (Sigurdson, 2008). It is apparent, though, that CWD is affecting wild and farmed cervid populations in endemic areas with some deer populations decreasing as a result.
Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle
Authors: Nicholas Haley1, Christopher Siepker2, Justin Greenlee3, Jürgen Richt4
VIEW AFFILIATIONS Affiliations: 1 1Midwestern Univerisity 2 2Kansas State University 3 3USDA, Agricultural Research Service 4 4Kansas State University
Published Ahead of Print: 31 March, 2016 Journal of General Virology doi: 10.1099/jgv.0.000438 Published Online: 31/03/2016
Chronic wasting disease (CWD) is a fatal neurodegenerative disease, classified as a prion disease or transmissible spongiform encephalopathy (TSE) similar to bovine spongiform encephalopathy (BSE). Cervids affected by CWD accumulate an abnormal protease resistant prion protein throughout the central nervous system (CNS), as well as in both lymphatic and excretory tissues - an aspect of prion disease pathogenesis not observed in cattle with BSE. Using seeded amplification through real time quaking induced conversion (RT-QuIC), we investigated whether the bovine host or prion agent was responsible for this aspect of TSE pathogenesis. We blindly examined numerous central and peripheral tissues from cattle inoculated with CWD for prion seeding activity. Seeded amplification was readily detected in the CNS, though rarely observed in peripheral tissues, with a limited distribution similar to that of BSE prions in cattle. This seems to indicate that prion peripheralization in cattle is a host-driven characteristic of TSE infection.
Friday, August 14, 2015
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
ARS VIRUS AND PRION RESEARCH / Research / Publication #277212
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Title: Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
Authors
item Greenlee, Justin item Nicholson, Eric item Smith, Jodi item Kunkle, Robert item Hamir, Amirali
Submitted to: Journal of Veterinary Diagnostic Investigation Publication
Type: Peer Reviewed Journal Publication Acceptance
Date: July 12, 2012
Publication Date: November 1, 2012
Citation: Greenlee, J.J., Nicholson, E.M., Smith, J.D., Kunkle, R.A., Hamir, A.N. 2012.
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation.
Journal of Veterinary Diagnostic Investigation. 24(6):1087-1093.
Interpretive Summary: Chronic Wasting Disease (CWD), a fatal neurodegenerative disease that occurs in farmed and wild cervids (deer and elk) of North America, is a transmissible spongiform encephalopathy (TSE). TSEs are caused by infectious proteins called prions that are resistant to various methods of decontamination and environmental degradation. Cattle could be exposed to chronic wasting disease (CWD) by contact with infected farmed or free-ranging cervids. The purpose of this study was to assess the potential transmission of CWD from elk to cattle after intracranial inoculation, the most direct route to test the potential of a host to replicate an isolate of the prion agent. This study reports that only 2 of 14 calves inoculated with CWD from elk had clinical signs or evidence of abnormal prion protein accumulation. These results suggest that cattle are unlikely to be susceptible to CWD if inoculated by a more natural route. This information could have an impact on regulatory officials developing plans to reduce or eliminate TSEs and farmers with concerns about ranging cattle on areas where CWD may be present.
Technical Abstract:
***Cattle could be exposed to the agent of chronic wasting disease (CWD) through contact with infected farmed or free-ranging cervids or exposure to contaminated premises. The purpose of this study was to assess the potential for CWD derived from elk to transmit to cattle after intracranial inoculation. Calves (n=14) were inoculated with brain homogenate derived from elk with CWD to determine the potential for transmission and define the clinicopathologic features of disease.
Cattle were necropsied if clinical signs occurred or at the termination of experiment (49 months post-inoculation (MPI)).
Clinical signs of poor appetite, weight loss, circling, and bruxism occurred in two cattle (14%) at 16 and 17 MPI, respectively.
Accumulation of abnormal prion protein (PrP**Sc) in these cattle was confined to the central nervous system with the most prominent immunoreactivity in midbrain, brainstem, and hippocampus with lesser immunoreactivity in the cervical spinal cord.
*** The rate of transmission was lower than in cattle inoculated with CWD derived from mule deer (38%) or white-tailed deer (86%).
Additional studies are required to fully assess the potential for cattle to develop CWD through a more natural route of exposure, but a low rate of transmission after intracranial inoculation suggests that risk of transmission through other routes is low.
***A critical finding here is that if CWD did transmit to exposed cattle, currently used diagnostic techniques would detect and differentiate it from other prion diseases in cattle based on absence of spongiform change, distinct pattern of PrP**Sc deposition, and unique molecular profile.
Monday, April 04, 2016
*** Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle ***
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.***
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Title: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease
Authors item Greenlee, Justin item Moore, S - item Smith, Jodi - item Kunkle, Robert item West Greenlee, M - Submitted to: American College of Veterinary Pathologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 12, 2015 Publication Date: N/A
Technical Abstract: The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n=5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the two inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy.
In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, two distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.
White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection
Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS
Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. Previous experiments demonstrated that white-tailed deer are susceptible to sheep-derived scrapie by intracranial inoculation. The purpose of this study was to determine susceptibility of white-tailed deer to scrapie after a natural route of exposure. Deer (n=5) were inoculated by concurrent oral (30 ml) and intranasal (1 ml) instillation of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with scrapie. Non-inoculated deer were maintained as negative controls. All deer were observed daily for clinical signs. Deer were euthanized and necropsied when neurologic disease was evident, and tissues were examined for abnormal prion protein (PrPSc) by immunohistochemistry (IHC) and western blot (WB). One animal was euthanized 15 months post-inoculation (MPI) due to an injury. At that time, examination of obex and lymphoid tissues by IHC was positive, but WB of obex and colliculus were negative. Remaining deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 MPI. Tissues from these deer were positive for scrapie by IHC and WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal and mesenteric lymph nodes, hemal node, Peyer’s patches, and spleen. ***This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by potential natural routes of inoculation. In-depth analysis of tissues will be done to determine similarities between scrapie in deer after intracranial and oral/intranasal inoculation and chronic wasting disease resulting from similar routes of inoculation.
2012
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer
Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA
snip...
The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in WTD after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile similar to CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like.
*** After a natural route of exposure, 100% of WTD were susceptible to scrapie.
Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer exhibited two different molecular profiles: samples from obex resembled CWD whereas those from cerebrum were similar to the original scrapie inoculum. On further examination by WB using a panel of antibodies, the tissues from deer with scrapie exhibit properties differing from tissues either from sheep with scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are strongly immunoreactive when probed with mAb P4, however, samples from WTD with scrapie are only weakly immunoreactive. In contrast, when probed with mAb’s 6H4 or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly immunoreactive and samples from WTD with scrapie are strongly positive. This work demonstrates that WTD are highly susceptible to sheep scrapie, but on first passage, scrapie in WTD is differentiable from CWD.
2011
*** After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie.
SEE;
Sunday, January 22, 2012
Chronic Wasting Disease CWD cervids interspecies transmission
Scrapie-like disorder in a Nyala (Tragelaphus angasi) IN CONFIDENCE
Spongiform encephalopathy has so far only been recorded in the sheep and goat, man, mink, and several deer including the mule deer, black tailed deer and the elk (most, if not all, of the deer incidents occurred in wild life parts in Wyoming and Colorado). Clinical cases in deer all occurred from 3 1/2 to 5 years old and usually 60-80% losses occurred over a 4 year period...
The clinical and neuropathological findings in F22 are consistent with the spongiform encephalopathies of animals and man. The agents causing spongiform encephalopathy in various species cannot be unequivocally distinguished and some isolates of human agent cause neurologic disease in goats indistinguishable from scrapie. The spongiform encephalopathies are invariably fatal once clinical signs of disease are evident and as very high fatality rates (79% of 67 animals) are recorded in Mule deer it is important that an awareness of the disease is maintained at Marwell.
”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.
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.
Spongiform Encephalopathy in Captive Wild ZOO BSE INQUIRY
Title: Pathological features of chronic wasting disease in reindeer and demonstration of horizontal transmission
*** Title: Pathological features of chronic wasting disease in reindeer and demonstration of horizontal transmission
*** December 2016 CDC Emerging Infectious Disease Journal CWD Horizontal Transmission
*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
Using in vitro prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.
Claudio Soto
Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.
Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.
=========================
***Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
========================
Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
with CWD TSE Prions, I am not sure there is any absolute yet, other than what we know with transmission studies, and we know tse prion kill, and tse prion are bad. science shows to date, that indeed soil, dirt, some better than others, can act as a carrier. same with objects, farm furniture. take it with how ever many grains of salt you wish, or not. if load factor plays a role in the end formula, then everything should be on the table, in my opinion...tss
Oral Transmissibility of Prion Disease Is Enhanced by Binding to Soil Particles
Author Summary
Transmissible spongiform encephalopathies (TSEs) are a group of incurable neurological diseases likely caused by a misfolded form of the prion protein. TSEs include scrapie in sheep, bovine spongiform encephalopathy (‘‘mad cow’’ disease) in cattle, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in humans. Scrapie and chronic wasting disease are unique among TSEs because they can be transmitted between animals, and the disease agents appear to persist in environments previously inhabited by infected animals. Soil has been hypothesized to act as a reservoir of infectivity and to bind the infectious agent. In the current study, we orally dosed experimental animals with a common clay mineral, montmorillonite, or whole soils laden with infectious prions, and compared the transmissibility to unbound agent. We found that prions bound to montmorillonite and whole soils remained orally infectious, and, in most cases, increased the oral transmission of disease compared to the unbound agent. The results presented in this study suggest that soil may contribute to environmental spread of TSEs by increasing the transmissibility of small amounts of infectious agent in the environment.
tse prion soil
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
The sources of dust borne prions are unknown but it seems reasonable to assume that faecal, urine, skin, parturient material and saliva-derived prions may contribute to this mobile environmental reservoir of infectivity. This work highlights a possible transmission route for scrapie within the farm environment, and this is likely to be paralleled in CWD which shows strong similarities with scrapie in terms of prion dissemination and disease transmission. The data indicate that the presence of scrapie prions in dust is likely to make the control of these diseases a considerable challenge.
>>>Particle-associated PrPTSE molecules may migrate from locations of deposition via transport processes affecting soil particles, including entrainment in and movement with air and overland flow. <<<
Fate of Prions in Soil: A Review
Christen B. Smith, Clarissa J. Booth, and Joel A. Pedersen*
Several reports have shown that prions can persist in soil for several years. Significant interest remains in developing methods that could be applied to degrade PrPTSE in naturally contaminated soils. Preliminary research suggests that serine proteases and the microbial consortia in stimulated soils and compost may partially degrade PrPTSE. Transition metal oxides in soil (viz. manganese oxide) may also mediate prion inactivation. Overall, the effect of prion attachment to soil particles on its persistence in the environment is not well understood, and additional study is needed to determine its implications on the environmental transmission of scrapie and CWD.
P.161: Prion soil binding may explain efficient horizontal CWD transmission
Conclusion. Silty clay loam exhibits highly efficient prion binding, inferring a durable environmental reservoir, and an efficient mechanism for indirect horizontal CWD transmission.
>>>Another alternative would be an absolute prohibition on the movement of deer within the state for any purpose. While this alternative would significantly reduce the potential spread of CWD, it would also have the simultaneous effect of preventing landowners and land managers from implementing popular management strategies involving the movement of deer, and would deprive deer breeders of the ability to engage in the business of buying and selling breeder deer. Therefore, this alternative was rejected because the department determined that it placed an avoidable burden on the regulated community.<<<
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
Timm Konold1*, Stephen A. C. Hawkins2, Lisa C. Thurston3, Ben C. Maddison4, Kevin C. Gough5, Anthony Duarte1 and Hugh A. Simmons1
1 Animal Sciences Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK, 2 Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, UK, 3 Surveillance and Laboratory Services, Animal and Plant Health Agency Penrith, Penrith, UK, 4 ADAS UK, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK, 5 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
Classical scrapie is an environmentally transmissible prion disease of sheep and goats. Prions can persist and remain potentially infectious in the environment for many years and thus pose a risk of infecting animals after re-stocking. In vitro studies using serial protein misfolding cyclic amplification (sPMCA) have suggested that objects on a scrapie affected sheep farm could contribute to disease transmission. This in vivo study aimed to determine the role of field furniture (water troughs, feeding troughs, fencing, and other objects that sheep may rub against) used by a scrapie-infected sheep flock as a vector for disease transmission to scrapie-free lambs with the prion protein genotype VRQ/VRQ, which is associated with high susceptibility to classical scrapie. When the field furniture was placed in clean accommodation, sheep became infected when exposed to either a water trough (four out of five) or to objects used for rubbing (four out of seven). This field furniture had been used by the scrapie-infected flock 8 weeks earlier and had previously been shown to harbor scrapie prions by sPMCA. Sheep also became infected (20 out of 23) through exposure to contaminated field furniture placed within pasture not used by scrapie-infected sheep for 40 months, even though swabs from this furniture tested negative by PMCA. This infection rate decreased (1 out of 12) on the same paddock after replacement with clean field furniture. Twelve grazing sheep exposed to field furniture not in contact with scrapie-infected sheep for 18 months remained scrapie free. The findings of this study highlight the role of field furniture used by scrapie-infected sheep to act as a reservoir for disease re-introduction although infectivity declines considerably if the field furniture has not been in contact with scrapie-infected sheep for several months. PMCA may not be as sensitive as VRQ/VRQ sheep to test for environmental contamination.
snip...
Discussion
Classical scrapie is an environmentally transmissible disease because it has been reported in naïve, supposedly previously unexposed sheep placed in pastures formerly occupied by scrapie-infected sheep (4, 19, 20). Although the vector for disease transmission is not known, soil is likely to be an important reservoir for prions (2) where – based on studies in rodents – prions can adhere to minerals as a biologically active form (21) and remain infectious for more than 2 years (22). Similarly, chronic wasting disease (CWD) has re-occurred in mule deer housed in paddocks used by infected deer 2 years earlier, which was assumed to be through foraging and soil consumption (23).
Our study suggested that the risk of acquiring scrapie infection was greater through exposure to contaminated wooden, plastic, and metal surfaces via water or food troughs, fencing, and hurdles than through grazing. Drinking from a water trough used by the scrapie flock was sufficient to cause infection in sheep in a clean building. Exposure to fences and other objects used for rubbing also led to infection, which supported the hypothesis that skin may be a vector for disease transmission (9). The risk of these objects to cause infection was further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid tissue after grazing on one of the paddocks, which contained metal hurdles, a metal lamb creep and a water trough in contact with the scrapie flock up to 8 weeks earlier, whereas no infection had been demonstrated previously in sheep grazing on this paddock, when equipped with new fencing and field furniture. When the contaminated furniture and fencing were removed, the infection rate dropped significantly to 8% of 12 sheep, with soil of the paddock as the most likely source of infection caused by shedding of prions from the scrapie-infected sheep in this paddock up to a week earlier.
This study also indicated that the level of contamination of field furniture sufficient to cause infection was dependent on two factors: stage of incubation period and time of last use by scrapie-infected sheep. Drinking from a water trough that had been used by scrapie sheep in the predominantly pre-clinical phase did not appear to cause infection, whereas infection was shown in sheep drinking from the water trough used by scrapie sheep in the later stage of the disease. It is possible that contamination occurred through shedding of prions in saliva, which may have contaminated the surface of the water trough and subsequently the water when it was refilled. Contamination appeared to be sufficient to cause infection only if the trough was in contact with sheep that included clinical cases. Indeed, there is an increased risk of bodily fluid infectivity with disease progression in scrapie (24) and CWD (25) based on PrPSc detection by sPMCA. Although ultraviolet light and heat under natural conditions do not inactivate prions (26), furniture in contact with the scrapie flock, which was assumed to be sufficiently contaminated to cause infection, did not act as vector for disease if not used for 18 months, which suggest that the weathering process alone was sufficient to inactivate prions.
PrPSc detection by sPMCA is increasingly used as a surrogate for infectivity measurements by bioassay in sheep or mice. In this reported study, however, the levels of PrPSc present in the environment were below the limit of detection of the sPMCA method, yet were still sufficient to cause infection of in-contact animals. In the present study, the outdoor objects were removed from the infected flock 8 weeks prior to sampling and were positive by sPMCA at very low levels (2 out of 37 reactions). As this sPMCA assay also yielded 2 positive reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay could not detect PrPSc on any of the objects above the background of the assay. False positive reactions with sPMCA at a low frequency associated with de novo formation of infectious prions have been reported (27, 28). This is in contrast to our previous study where we demonstrated that outdoor objects that had been in contact with the scrapie-infected flock up to 20 days prior to sampling harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions (12)] and was significantly more positive by the assay compared to analogous samples from the scrapie-free farm. This discrepancy could be due to the use of a different sPMCA substrate between the studies that may alter the efficiency of amplification of the environmental PrPSc. In addition, the present study had a longer timeframe between the objects being in contact with the infected flock and sampling, which may affect the levels of extractable PrPSc. Alternatively, there may be potentially patchy contamination of this furniture with PrPSc, which may have been missed by swabbing. The failure of sPMCA to detect CWD-associated PrP in saliva from clinically affected deer despite confirmation of infectivity in saliva-inoculated transgenic mice was associated with as yet unidentified inhibitors in saliva (29), and it is possible that the sensitivity of sPMCA is affected by other substances in the tested material. In addition, sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more difficult from furniture exposed to weather, which is supported by the observation that PrPSc was detected by sPMCA more frequently in indoor than outdoor furniture (12). A recent experimental study has demonstrated that repeated cycles of drying and wetting of prion-contaminated soil, equivalent to what is expected under natural weathering conditions, could reduce PMCA amplification efficiency and extend the incubation period in hamsters inoculated with soil samples (30). This seems to apply also to this study even though the reduction in infectivity was more dramatic in the sPMCA assays than in the sheep model. Sheep were not kept until clinical end-point, which would have enabled us to compare incubation periods, but the lack of infection in sheep exposed to furniture that had not been in contact with scrapie sheep for a longer time period supports the hypothesis that prion degradation and subsequent loss of infectivity occurs even under natural conditions.
In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination. These results suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the detection of environmentally associated scrapie, and suggest that extremely low levels of scrapie contamination are able to cause infection in susceptible sheep genotypes.
Keywords: classical scrapie, prion, transmissible spongiform encephalopathy, sheep, field furniture, reservoir, serial protein misfolding cyclic amplification
Wednesday, December 16, 2015
*** Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission ***
*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
snip...see full text ;
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
cwd resistant cervid???
***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 CWO
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
Saturday, May 28, 2016
*** Infection and detection of PrPCWD in soil from CWD infected farm in Korea Prion 2016 Tokyo ***
the tse prion aka mad cow type disease is not your normal pathogen.
The TSE prion disease survives ashing to 600 degrees celsius, that’s around 1112 degrees farenheit.
you cannot cook the TSE prion disease out of meat. you can take the ash and mix it with saline and inject that ash into a mouse, and the mouse will go down with TSE.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production as well.
the TSE prion agent also survives Simulated Wastewater Treatment Processes.
IN fact, you should also know that the TSE Prion agent will survive in the environment for years, if not decades.
you can bury it and it will not go away.
The TSE agent is capable of infected your water table i.e. Detection of protease-resistant cervid prion protein in water from a CWD-endemic area.
it’s not your ordinary pathogen you can just cook it out and be done with.
that’s what’s so worrisome about Iatrogenic mode of transmission, a simple autoclave will not kill this TSE prion agent.
cwd to humans, consumption, exposure, sub-clinical, iatrogenic, what if ?
Wednesday, September 7, 2016
*** An assessment of the long-term persistence of prion infectivity in aquatic environments
Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
The data presented here demonstrate that sPMCA can detect low levels of PrPCWD in the environment, corroborate previous biological and experimental data suggesting long term persistence of prions in the environment2,3 and imply that PrPCWD accumulation over time may contribute to transmission of CWD in areas where it has been endemic for decades. This work demonstrates the utility of sPMCA to evaluate other environmental water sources for PrPCWD, including smaller bodies of water such as vernal pools and wallows, where large numbers of cervids congregate and into which prions from infected animals may be shed and concentrated to infectious levels.
Tuesday, December 13, 2016
Norway Chronic Wasting Disease CWD TSE Prion disease Skrantesjuke December 2016 Update
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
SATURDAY, JANUARY 14, 2017
CHRONIC WASTING DISEASE CWD TSE PRION GLOBAL UPDATE
JANUARY 14, 2017
WEDNESDAY, JANUARY 18, 2017
Ireland Department of Agriculture confirmed a case of Atypical BSE 18 year old cow
SUNDAY, JANUARY 15, 2017
US lifts French beef MAD COW BSE import embargo, France says… LOL!
Thursday, December 08, 2016
USDA APHIS National Scrapie Eradication Program October 2016 Monthly Report Fiscal Year 2017 atypical NOR-98 Scrapie
Monday, January 09, 2017
Oral Transmission of L-Type Bovine Spongiform Encephalopathy Agent among Cattle CDC Volume 23, Number 2—February 2017
TUESDAY, JANUARY 17, 2017
FDA PART 589 -- SUBSTANCES PROHIBITED FROM USE IN ANIMAL FOOD OR FEEDVIOLATIONS OFFICIAL ACTION INDICATED OAI UPDATE 2016 to 2017 BSE TSE PRION
MONDAY, JANUARY 16, 2017
APHIS Bovine Spongiform Encephalopathy (BSE): Ongoing Surveillance Program Last Modified: Jan 5, 2017
Wednesday, December 21, 2016
TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES 2016 ANNUAL REPORT ARS RESEARCH
WEDNESDAY, JANUARY 18, 2017
EU-approved rapid tests might underestimate bovine spongiform encephalopathy infection in goats
THURSDAY, JANUARY 19, 2017
Variant Creutzfeldt–Jakob Disease in a Patient with Heterozygosity at PRNP Codon 129
FRIDAY, JANUARY 20, 2017
Many more people could still die from mad cow disease in the UK
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
1:07 PM
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