Risk Advisory Opinion: Potential Human Health Risks from Chronic Wasting Disease CFIA, PHAC, HC (HPFB and FNIHB), INAC, Parks Canada, ECCC and AAFC
Health Products and Food Branch (HPFB)
Risk Advisory Opinion: Potential Human Health Risks from Chronic Wasting Disease
Prepared by: Bureau of Microbial Hazards (BMH), Food Directorate, Health Products and Food Branch, Health Canada
Date: April 26, 2017 Issue: Chronic Wasting Disease (CWD) is a progressive, fatal, transmissible neurological disease that naturally infects cervids, and has been identified in deer, elk, moose, and reindeer.
To date there is no direct evidence that CWD has been or can be transmitted from animals to humans.
However, initial findings from a laboratory research project funded by the Alberta Prion Research Institute (APRI) and Alberta Livestock Meat Agency (ALMA), and led by a Canadian Food Inspection Agency (CFIA) scientist indicate that CWD has been transmitted to cynomolgus macaques (the non-human primate species most closely related to humans that may be used in research), through both the intracranial and oral routes of exposure.
Both infected brain and muscle tissues were found to transmit disease.
Health Canada’s Health Products and Food Branch (HPFB) was asked to consider the impact of these findings on the Branch’s current position on CWD in health products and foods.
Summary and Recommendation:
Health Canada’s Health Products and Food Branch (HPFB) is responsible for assessing risks to human health from diseases of animal origin that may be transmitted through health products and food, and for developing regulations and policies to mitigate risks from products regulated under the Food and Drug Act as well as various associated regulations.
While extensive disease surveillance in Canada and elsewhere has not provided any direct evidence that CWD has infected humans, the potential for CWD to be transmitted to humans cannot be excluded. In exercising precaution, HPFB continues to advocate that the most prudent approach is to consider that CWD has the potential to infect humans.
This position has been aligned with that of the World Health Organization (WHO) since the late 1990s, and remains consistent with the WHO’s 2012 position that “No tissue that is likely to contain the bovine spongiform encephalopathy (BSE) agent, nor part or product of any animal which has shown signs of a TSE should enter the (human or animal) food chain.”
This precautionary position on TSEs is also consistent with the conclusions documented by the Transmissible Spongiform Encephalopathy (TSE) Secretariat in 2003, and a systematic literature review conducted by the Public Health Agency of Canada (PHAC) in 2017.
The findings of the macaque experiment do not change HPFB’s current position with respect to the safety of food and health products and CWD, which considers that a precautionary approach to the management of the potential risks of exposure through food and health products is warranted.
Background: Chronic Wasting Disease (CWD) is a fatal disease that has been detected in cervids. To date, the disease has been identified in deer, elk, moose, and reindeer. CWD belongs to a class of diseases called transmissible spongiform encephalopathies (TSEs).
Along with other well-known TSEs, such as bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep and goats and Creutzfeldt–Jakob disease (CJD) and variant CJD (vCJD) in humans, CWD is characterized by the accumulation of abnormal misfolded proteins (called prions) in multiple organs and tissues, including lymphatic, muscle and neural tissues.
CWD was first recognized as a fatal wasting disease of captive deer in the United States in the late 1960s, and was later identified as a TSE in 1980. In Canada, CWD was first detected in the Toronto Zoo in the 1970s and diagnosed in farmed elk in 1996.
The first Canadian case in a wild cervid was confirmed in a mule deer in Saskatchewan in November 2000.
The disease has now been detected in cervids in 24 US states and two Canadian provinces (Alberta and Saskatchewan).
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The exact routes and mechanisms of CWD transmission between animals remain unclear. There is evidence that infection is transmitted directly from animal to animal during close contact with saliva, urine and feces, and indirectly through the environment.
While incubation periods may be variable, once the disease is contracted, the time to presentation of clinical symptoms is about 16 to 36 months.
It is only in the later, clinical stages that CWD is typified by the chronic weight loss and behavioral changes that eventually lead to death.
In 2003, Health Canada’s TSE secretariat assessed the potential for CWD to pose a hazard to human health.
It was noted at that time that there was no evidence to indicate that CWD had ever infected a human.
Given the lack of scientific evidence of the potential for CWD to become a human pathogen, it was stated that the most prudent course of action was to consider that CWD could have the potential to infect humans, and thus take a precautionary approach to its management, which was consistent with the position taken by the World Health Organization (WHO).
The Public Health Agency of Canada (PHAC) recently published a systematic review summarizing the evidence in the scientific literature on the transmissibility of CWD prions to humans (2017).
This review summarized available epidemiological evidence, as well as evidence on CWD infectivity using experimental models, including non-human primates, transgenic mice, and in vitro experiments.
The review showed that animal models using humanized transgenic mice did not demonstrate transmission.
Two transmission experiments using squirrel monkeys have been able to show prion disease after intracerebral and oral inoculation with CWD prions.
The systematic review also summarized two transmission experiments using macaques (a non-human primate species considered genetically closer to humans than squirrel monkeys) which, at the time of review, had not caused prion disease after inoculation with CWD prions by several modes (e.g., intracerebral, oral) up to 10 years of observation since exposure to CWD prions.
Health Portfolio partners were recently made aware of initial findings from a research project led by a CFIA scientist that have demonstrated that cynomolgus macaques can be infected via intracranial exposure and oral gavage with CWD infected muscle.
These findings suggest that CWD, under specific experimental conditions, has the potential to cross the human species barrier, including by enteral feeding of CWD infected muscle.
While the study is ongoing, and findings have yet to be subjected to formal peer review, the initial results will be presented at PRION 2017, an annual international conference on TSE diseases (Edinburgh May 23-26, 2017).
In advance of this conference, a multi-departmental working group (including CFIA, PHAC, HC (HPFB and FNIHB), INAC, Parks Canada, ECCC and AAFC) has been established to coordinate risk management and risk communication activities.
As the lead in managing the potential human health risks related to health products and food that could contain cervid materials, Health Canada’s HPFB has considered the initial findings of this research within the context of known and accepted science and evidence related to the transmissibility of CWD to cervids, other animals, transgenic mice, and its potential to be transmissible to humans, to provide an updated advisory opinion of the potential risk to human health.
This opinion is provided to the working group to inform the assessment of current CWD control policies in Canada as well as the advice related to the potential risks posed by CWD through the consumption of cervid food products.
Health Canada’s Current Position on TSEs in Health Products and Food: HPFB has previously addressed concerns regarding human exposure to BSE, and remains alert to the possibility that other animal TSEs such as scrapie and CWD may also pose risks to human health.
HPFB maintains a precautionary stance in relation to human exposure to TSEs through health products and food.
In 2003, HPFB adopted the position that no material derived from an animal known to be infected with any TSE (including CWD) should be used or consumed by humans or animals.
This position was, and continues to be, consistent with the position of the WHO.
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HPFB requires pre-market review and approval of all human therapeutics, biologics and genetic therapies, veterinary drugs and natural health products intended for sale in Canada.
This includes a requirement for license holders of these products to maintain documentation and provide information for any materials of animal origin that may be used within their products, including therapeutic substances, reagents and excipients.
This documentation can include letters of attestation, Certificates of Suitability or Veterinary Certificates.
While there are no specific federal regulations related to the use(s) of cervids in foods, current federal animal disease control policies support the diversion of known CWD-infected farmed animals away from the food and feed supply.
Outreach, communications, and monitoring programs related to wild cervids, as well as disease surveillance for farmed cervids, fall within the jurisdiction of the Provincial and/or Territorial governments.
Hazard Characterization In 2003, Health Canada’s TSE secretariat assessed the potential for CWD to pose a hazard to human health.
Given the lack of scientific evidence of the potential for CWD to become a human pathogen, it was stated that the most prudent course of action was to consider that CWD could have the potential to infect humans, and thus take a precautionary approach to its management.
Following nearly two decades of ongoing human prion disease surveillance and retrospective review by PHAC and the Centers for Disease Control and Prevention (CDC), there have been no identified cases of human prion disease or any other outcome attributed to CWD in Canada, the USA, or elsewhere.
In 2017, PHAC published a systematic literature review of the evidence for the transmissibility of CWD to humans, which included evidence of successful transmission of CWD intracranially and orally to squirrel monkeys.
From this review, it was concluded that CWD transmission to humans has not been recorded.
In five epidemiological studies no association between CWD exposure and human prion disease was identified.
Some cases of CJD had a history of exposure to cervids and venison in CWD affected regions, but no definitive link to CWD could be found.
The assessment of the evidence captured in this systematic review does not support the hypothesis that CWD is readily transmitted to humans; however, the positive evidence of interspecies transmission from in vivo and in vitro experiments indicates that the species barrier is not absolute.
The initial findings from the APRI/ALMA-funded macaque experiment are consistent with this conclusion.
Potential Sources of Exposure to Cervids and Cervid-derived Materials:
Canadians may be exposed to cervids, and materials derived from cervids through a variety of sources, and routes of exposure, including in their diet and through the use of natural health products that contain antler velvet.
There is also the potential for Canadians to be exposed to cervids through farming (including veterinary services), slaughter, velvet harvest, as well as through field dressing of hunted animals, preparing trophies and/or the use of cervid-derived materials (e.g., urine) as hunting lures.
While monitoring and control programs are in place to reduce the likelihood that animals known to be infected with CWD reach the marketplace, the possibility cannot be excluded that some of these sources of exposure may be derived from animals with CWD.
Cervid meat (venison) is available in many of the same cuts and processed meat products as for other meat products.
While consumption survey estimates for the general Canadian population (2004 Canadian Community Health Survey, Cycle 2.2) indicate that overall venison consumption is quite low, there are known subpopulations, including rural and Indigenous populations that have higher dietary exposures to this food.
In addition, populations that rely on cervids as an important source of protein are more likely to hunt and/or consume wild cervids.
There are no human biologics or genetic therapies licensed in Canada that contain ingredients of cervid origin, and it is considered unlikely that cervid materials or ingredients would be used in the manufacture
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of these human therapeutic products, including medical devices.
There are approximately 200 licenced natural health products (NHPs) that contain ingredients of cervid origin such as antler velvet.
Impact of New Findings on Human Health Risk Assessment:
There have been no known cases of human prion disease or any other outcome attributable to CWD identified to date.
National surveillance of all forms of CJD by PHAC has yielded no direct evidence that CWD has infected humans in Canada.
However, in the absence of definitive information related to the transmissibility of CWD to humans, and in light of the evidence that BSE can be transmitted to humans, HPFB has maintained a precautionary position with respect to CWD that is in agreement with the WHO’s 2012 recommendation that “No tissue that is likely to contain the BSE agent, nor part or product of any animal which has shown signs of a TSE should enter the (human or animal) food chain.”.
The initial findings from the experimental non-human primate transmission study do not change HPFB’s position with respect to food and health products, and a continued precautionary approach to the management of the potential risks of exposure through food and health products is warranted.
HPFB continues to recommend avoiding consumption of foods from known infected or any diseased animals, and taking precautions when handling cervid carcasses.
In addition, in areas where CWD is known to occur in wild cervids, continued consistent Federal and P/T communications, warning and precautions should be provided to groups who may be expected to have higher exposures to cervids through hunting and diet (e.g., rural and Indigenous populations).
While current animal disease control policies support the diversion of known CWD-infected animals away from the food and feed supply, research and development of sensitive detection methods and antemortem sampling techniques remain crucial for ensuring accurate diagnoses.
Continued research into TSEs and continued epidemiologic surveillance for human prion diseases are required. HPFB will continue to review and monitor scientific literature related to CWD, as well as these initial findings and other emerging research related to the potential transmissibility of CWD to humans.
The Branch will continue to update its position on animal TSEs as new scientific evidence indicates the need for further protection of public health.
Reviewed by: Veterinary Drugs Directorate, HPFB Natural and Non-Prescription Health Products Directorate, HPFB Biologics and Genetics Therapies Directorate, HPFB Therapeutic Products Directorate, HPFB Marketed Health Products Directorate, HPFB Approved by: Denise MacGillivray, Director – Bureau of Microbial Hazards, FD, HPFB Date: April 26, 2017
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References Waddell, L., Greig, J., Mascarenhas, M., Otten, A., Corrin, T., Hierlihy, K. Current evidence on the transmissibility of chronic wasting disease prions to humans - A systematic review. Transbound Emerg Dis. 2017 Jan 30. doi: 10.1111/tbed.12612. [Epub ahead of print] World Health Organization - Variant Creutzfeldt-Jakob disease - Fact sheet N°180: Revised February 2012. (http://www.who.int/mediacentre/factsheets/fs180/en/) World Health Organization - Bovine spongiform encephalopathy - Fact Sheet N°113 Revised November 2002 (http://www.wiredhealthresources.net/resources/NA/WHOFS_BovineSpongiformEncephalopathy.pdf) Chronic Wasting Disease - What to expect if your animals may be infected. (http://www.inspection.gc.ca/animals/terrestrial-animals/diseases/reportable/cwd/if-your-animals-may-beinfected/eng/1330188848236/1330189018195) Chronic Wasting Disease of Deer and Elk: A Canadian Perspective. TSE Secretariat, Health Canada January 2003. Chronic Wasting Disease of Cervids: A Human Health Concern? TSE Secretariat, Health Canada March 2003. Chronic Wasting Disease: A Review for Health Canada; prepared by Dr Terry Spraker, University of Colorado for the TSE Secretariat, Health Canada, March 2006.
First evidence of intracranial and peroral transmission of Chronic Wasting Disease (CWD) into Cynomolgus macaques: a work in progress
Stefanie Czub1, Walter Schulz-Schaeffer2, Christiane Stahl-Hennig3, Michael Beekes4, Hermann Schaetzl5 and Dirk Motzkus6 1
University of Calgary Faculty of Veterinary Medicine/Canadian Food Inspection Agency; 2Universitatsklinikum des Saarlandes und Medizinische Fakultat der Universitat des Saarlandes; 3 Deutsches Primaten Zentrum/Goettingen; 4 Robert-Koch-Institut Berlin; 5 University of Calgary Faculty of Veterinary Medicine; 6 presently: Boehringer Ingelheim Veterinary Research Center; previously: Deutsches Primaten Zentrum/Goettingen
This is a progress report of a project which started in 2009. 21 cynomolgus macaques were challenged with characterized CWD material from white-tailed deer (WTD) or elk by intracerebral (ic), oral, and skin exposure routes. Additional blood transfusion experiments are supposed to assess the CWD contamination risk of human blood product. Challenge materials originated from symptomatic cervids for ic, skin scarification and partially per oral routes (WTD brain). Challenge material for feeding of muscle derived from preclinical WTD and from preclinical macaques for blood transfusion experiments. We have confirmed that the CWD challenge material contained at least two different CWD agents (brain material) as well as CWD prions in muscle-associated nerves.
Here we present first data on a group of animals either challenged ic with steel wires or per orally and sacrificed with incubation times ranging from 4.5 to 6.9 years at postmortem. Three animals displayed signs of mild clinical disease, including anxiety, apathy, ataxia and/or tremor. In four animals wasting was observed, two of those had confirmed diabetes. All animals have variable signs of prion neuropathology in spinal cords and brains and by supersensitive IHC, reaction was detected in spinal cord segments of all animals. Protein misfolding cyclic amplification (PMCA), real-time quaking-induced conversion (RT-QuiC) and PET-blot assays to further substantiate these findings are on the way, as well as bioassays in bank voles and transgenic mice.
At present, a total of 10 animals are sacrificed and read-outs are ongoing. Preclinical incubation of the remaining macaques covers a range from 6.4 to 7.10 years. Based on the species barrier and an incubation time of > 5 years for BSE in macaques and about 10 years for scrapie in macaques, we expected an onset of clinical disease beyond 6 years post inoculation.
PRION 2017 DECIPHERING NEURODEGENERATIVE DISORDERS
Subject: PRION 2017 CONFERENCE DECIPHERING NEURODEGENERATIVE DISORDERS VIDEO
PRION 2017 CONFERENCE DECIPHERING NEURODEGENERATIVE DISORDERS
PRION 2017 CONFERENCE VIDEO
Chronic Wasting Disease CWD TSE Prion to Humans, who makes that final call, when, or, has it already happened?
TUESDAY, JUNE 13, 2017
PRION 2017 CONFERENCE ABSTRACT First evidence of intracranial and peroral transmission of Chronic Wasting Disease (CWD) into Cynomolgus macaques: a work in progress
TUESDAY, JUNE 13, 2017
PRION 2017 CONFERENCE ABSTRACT Chronic Wasting Disease in European moose is associated with PrPSc features different from North American CWD
TUESDAY, JULY 04, 2017
*** PRION 2017 CONFERENCE ABSTRACTS ON CHRONIC WASTING DISEASE CWD TSE PRION ***
URINE
SUNDAY, JULY 16, 2017
*** Temporal patterns of chronic wasting disease prion excretion in three cervid species ***
WEDNESDAY, JULY 26, 2017
Chronic wasting disease continues to spread Disease of cervids causing local population declines
THURSDAY, JULY 27, 2017
PA PGC: Suspicious Free-Ranging Deer with identification tags in their ears Discovered In Elk County will be tested for CWD
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).***
''There are approximately 200 licenced natural health products (NHPs) that contain ingredients of cervid origin such as antler velvet.''
Volume 15, Number 5—May 2009
Research
Chronic Wasting Disease Prions in Elk Antler Velvet
''There are approximately 200 licenced natural health products (NHPs) that contain ingredients of cervid origin such as antler velvet.''
Sunday, November 10, 2013
LARGE CJD TSE PRION POTENTIAL CASE STUDY AMONG HUMANS WHO TAKE DEER ANTLER VELVET WILL BE ONGOING FOR YEARS IF NOT DECADES, but who's cares $
''There are approximately 200 licenced natural health products (NHPs) that contain ingredients of cervid origin such as antler velvet.''
MONDAY, JUNE 19, 2017
FDA DOES NOT have mandatory established specifications for animal-derived ingredients to ensure they are BSE free in Nutritional Supplements
''There are approximately 200 licenced natural health products (NHPs) that contain ingredients of cervid origin such as antler velvet.''
ABOUT that deer antler spray and CWD TSE PRION...
I have been screaming this since my neighbors mom died from cjd, and she had been taking a supplement that contained bovine brain, bovine eyeball, and other SRMs specified risk materials, the most high risk for mad cow disease.
just saying...
I made a submission to the BSE Inquiry long ago during the BSE Inquiry days, and they seemed pretty interested.
Sender: "Patricia Cantos"
To: "Terry S Singeltary Sr. (E-mail)"
Subject: Your submission to the Inquiry
Date: Fri, 3 Jul 1998 10:10:05 +0100
3 July 1998
Mr Terry S Singeltary Sr.
E-Mail: Flounder at wt.net
Ref: E2979
Dear Mr Singeltary,
Thank you for your E-mail message of the 30th of June 1998 providing the Inquiry with your further comments.
Thank you for offering to provide the Inquiry with any test results on the nutritional supplements your mother was taking before she died.
As requested I am sending you our general Information Pack and a copy of the Chairman's letter. Please contact me if your system cannot read the attachments.
Regarding your question, the Inquiry is looking into many aspects of the scientific evidence on BSE and nvCJD. I would refer you to the transcripts of evidence we have already heard which are found on our internet site at ;
Could you please provide the Inquiry with a copy of the press article you refer to in your e-mail? If not an approximate date for the article so that we can locate it?
In the meantime, thank you for you comments. Please do not hesitate to contact me on...
snip...end...tss
everyone I tell this too gets it screwed up...MY MOTHER WAS NOT TAKING THOSE SUPPLEMENTS IPLEX (that I ever knew of). this was my neighbors mother that died exactly one year _previously_ and to the day of sporadic CJD that was diagnosed as Alzheimer’s at first. my mother died exactly a year later from the Heidenhain Variant of Creutzfeldt Jakob Disease hvCJD, and exceedingly rare strains of the ever growing sporadic CJD’s. _both_ cases confirmed. ...kind regards, terry
TSEs i.e. mad cow disease's BSE/BASE and NUTRITIONAL SUPPLEMENTS
IPLEX, mad by standard process;
vacuum dried bovine BRAIN, bone meal, bovine EYE, veal Bone, bovine liver powder, bovine adrenal, vacuum dried bovine kidney, and vacuum dried porcine stomach.
also;
what about potential mad cow candy bars ?
see their potential mad cow candy bar list too...
THESE are just a few of MANY of just this ONE COMPANY...TSS
DEPARTMENT OF HEALTH AND HUMAN SERVICES
FOOD AND DRUG ADMINISTRATION CENTER FOR BIOLOGICS EVALUATION AND RESEARCH
TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES ADVISORY COMMITTEE
Friday, January 19, 2001 snip...
17 But I think that we could exhibit some quite
18 reasonable concern about blood donors who are taking dietary
19 supplements that contain a certain amount of unspecified-
20 origin brain, brain-related, brain and pituitary material.
21 If they have done this for more than a sniff or something
22 like that, then, perhaps, they should be deferred as blood
23 donors.
24 That is probably worse than spending six months in
25 the U.K.
1/19/01
3681t2.rtf(845) page 501
see full text ;
*** unbelievable, absolutely unbelievable that this is still going on in 2017. please remember, some 300,000 cattle in the UK died from mad cow disease due to nothing more than a crude nutritional supplement called CATTLE FEED. ...terry
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Location: Virus and Prion Research
Title: Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease
Author item Moore, Sarah item Kunkle, Robert item Kondru, Naveen item Manne, Sireesha item Smith, Jodi item Kanthasamy, Anumantha item West Greenlee, M item Greenlee, Justin
Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 3/15/2017 Publication Date: N/A Citation: N/A Interpretive Summary:
Technical Abstract: Aims: Chronic wasting disease (CWD) is a naturally-occurring, fatal neurodegenerative disease of cervids. We previously demonstrated that disease-associated prion protein (PrPSc) can be detected in the brain and retina from pigs challenged intracranially or orally with the CWD agent. In that study, neurological signs consistent with prion disease were observed only in one pig: an intracranially challenged pig that was euthanized at 64 months post-challenge. The purpose of this study was to use an antigen-capture immunoassay (EIA) and real-time quaking-induced conversion (QuIC) to determine whether PrPSc is present in lymphoid tissues from pigs challenged with the CWD agent.
Methods: At two months of age, crossbred pigs were challenged by the intracranial route (n=20), oral route (n=19), or were left unchallenged (n=9). At approximately 6 months of age, the time at which commercial pigs reach market weight, half of the pigs in each group were culled (<6 challenge="" groups="" month="" pigs="" remaining="" the="">6 month challenge groups) were allowed to incubate for up to 73 months post challenge (mpc). The retropharyngeal lymph node (RPLN) was screened for the presence of PrPSc by EIA and immunohistochemistry (IHC). The RPLN, palatine tonsil, and mesenteric lymph node (MLN) from 6-7 pigs per challenge group were also tested using EIA and QuIC.
Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 5="" 6="" at="" by="" detected="" eia.="" examined="" group="" in="" intracranial="" least="" lymphoid="" month="" months="" of="" one="" pigs="" positive="" prpsc="" quic="" the="" tissues="" was="">6 months group, 5/6 pigs in the oral <6 4="" and="" group="" months="" oral="">6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%). Conclusions:
This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge.
CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period. This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease.
Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
CONFIDENTIAL
EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY
While this clearly is a cause for concern we should not jump to the conclusion that this means that pigs will necessarily be infected by bone and meat meal fed by the oral route as is the case with cattle. ...
we cannot rule out the possibility that unrecognised subclinical spongiform encephalopathy could be present in British pigs though there is no evidence for this: only with parenteral/implantable pharmaceuticals/devices is the theoretical risk to humans of sufficient concern to consider any action.
Our records show that while some use is made of porcine materials in medicinal products, the only products which would appear to be in a hypothetically ''higher risk'' area are the adrenocorticotrophic hormone for which the source material comes from outside the United Kingdom, namely America China Sweden France and Germany. The products are manufactured by Ferring and Armour. A further product, ''Zenoderm Corium implant'' manufactured by Ethicon, makes use of porcine skin - which is not considered to be a ''high risk'' tissue, but one of its uses is described in the data sheet as ''in dural replacement''. This product is sourced from the United Kingdom.....
snip...see much more here ;
WEDNESDAY, APRIL 05, 2017
Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease
TUESDAY, APRIL 18, 2017
*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***
***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.
SNIP...
Monday, April 04, 2016
*** Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle ***
ELEPHANT IN THE ROOM $$$
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).***
SPONTANEOUS ATYPICAL BOVINE SPONGIFORM ENCEPHALOPATHY
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
Saturday, 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 efficiency comparable to that of cattle BSE. While the efficiency 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.
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.
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
*** 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). ***
*** 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). ***
*** 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 ;
you can see more evidence here ;
*** 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
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
Cervid to human prion transmission
Kong, Qingzhong
Case Western Reserve University, Cleveland, OH, United States
Abstract
Prion disease is transmissible and invariably fatal. Chronic wasting disease (CWD) is the prion disease affecting deer, elk and moose, and it is a widespread and expanding epidemic affecting 22 US States and 2 Canadian provinces so far. CWD poses the most serious zoonotic prion transmission risks in North America because of huge venison consumption (>6 million deer/elk hunted and consumed annually in the USA alone), significant prion infectivity in muscles and other tissues/fluids from CWD-affected cervids, and usually high levels of individual exposure to CWD resulting from consumption of the affected animal among often just family and friends. However, we still do not know whether CWD prions can infect humans in the brain or peripheral tissues or whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no essays to reliably detect CWD infection in humans. We hypothesize that:
(1) The classic CWD prion strain can infect humans at low levels in the brain and peripheral lymphoid tissues;
(2) The cervid-to-human transmission barrier is dependent on the cervid prion strain and influenced by the host (human) prion protein (PrP) primary sequence;
(3) Reliable essays can be established to detect CWD infection in humans; and
(4) CWD transmission to humans has already occurred. We will test these hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in vitro approaches.
Aim 1 will prove that the classical CWD strain may infect humans in brain or peripheral lymphoid tissues at low levels by conducting systemic bioassays in a set of "humanized" Tg mouse lines expressing common human PrP variants using a number of CWD isolates at varying doses and routes. Experimental "human CWD" samples will also be generated for Aim 3.
Aim 2 will test the hypothesis that the cervid-to-human prion transmission barrier is dependent on prion strain and influenced by the host (human) PrP sequence by examining and comparing the transmission efficiency and phenotypes of several atypical/unusual CWD isolates/strains as well as a few prion strains from other species that have adapted to cervid PrP sequence, utilizing the same panel of humanized Tg mouse lines as in Aim 1.
Aim 3 will establish reliable essays for detection and surveillance of CWD infection in humans by examining in details the clinical, pathological, biochemical and in vitro seeding properties of existing and future experimental "human CWD" samples generated from Aims 1-2 and compare them with those of common sporadic human Creutzfeldt-Jakob disease (sCJD) prions.
Aim 4 will attempt to detect clinical CWD-affected human cases by examining a significant number of brain samples from prion-affected human subjects in the USA and Canada who have consumed venison from CWD-endemic areas utilizing the criteria and essays established in Aim 3. The findings from this proposal will greatly advance our understandings on the potential and characteristics of cervid prion transmission in humans, establish reliable essays for CWD zoonosis and potentially discover the first case(s) of CWD infection in humans.
Public Health Relevance There are significant and increasing human exposure to cervid prions because chronic wasting disease (CWD, a widespread and highly infectious prion disease among deer and elk in North America) continues spreading and consumption of venison remains popular, but our understanding on cervid-to-human prion transmission is still very limited, raising public health concerns. This proposal aims to define the zoonotic risks of cervid prions and set up and apply essays to detect CWD zoonosis using mouse models and in vitro methods. The findings will greatly expand our knowledge on the potentials and characteristics of cervid prion transmission in humans, establish reliable essays for such infections and may discover the first case(s) of CWD infection in humans.
Key Molecular Mechanisms of TSEs
Zabel, Mark D.
Colorado State University-Fort Collins, Fort Collins, CO, United States
Abstract Prion diseases, or transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative diseases affecting humans, cervids, bovids, and ovids. The absolute requirement of PrPC expression to generate prion diseases and the lack of instructional nucleic acid define prions as unique infectious agents. Prions exhibit species-specific tropism, inferring that unique prion strains exist that preferentially infct certain host species and confront transmission barriers to heterologous host species. However, transmission barriers are not absolute. Scientific consensus agrees that the sheep TSE scrapie probably breached the transmission barrier to cattle causing bovine spongiform encephalopathy that subsequently breached the human transmission barrier and likely caused several hundred deaths by a new-variant form of the human TSE Creutzfeldt-Jakob disease in the UK and Europe. The impact to human health, emotion and economies can still be felt in areas like farming, blood and organ donations and the threat of a latent TSE epidemic. This precedent raises the real possibility of other TSEs, like chronic wasting disease of cervids, overcoming similar human transmission barriers. A groundbreaking discovery made last year revealed that mice infected with heterologous prion strains facing significant transmission barriers replicated prions far more readily in spleens than brains6. Furthermore, these splenic prions exhibited weakened transmission barriers and expanded host ranges compared to neurogenic prions. These data question conventional wisdom of avoiding neural tissue to avoid prion xenotransmission, when more promiscuous prions may lurk in extraneural tissues. Data derived from work previously funded by NIH demonstrate that Complement receptors CD21/35 bind prions and high density PrPC and differentially impact prion disease depending on the prion isolate or strain used. Recent advances in live animal and whole organ imaging have led us to generate preliminary data to support novel, innovative approaches to assessing prion capture and transport. We plan to test our unifying hypothesis for this proposal that CD21/35 control the processes of peripheral prion capture, transport, strain selection and xenotransmission in the following specific aims.
1. Assess the role of CD21/35 in splenic prion strain selection and host range expansion.
2. Determine whether CD21/35 and C1q differentially bind distinct prion strains
3. Monitor the effects of CD21/35 on prion trafficking in real time and space
4. Assess the role of CD21/35 in incunabular prion trafficking
Public Health Relevance Transmissible spongiform encephalopathies, or prion diseases, are devastating illnesses that greatly impact public health, agriculture and wildlife in North America and around the world. The impact to human health, emotion and economies can still be felt in areas like farming, blood and organ donations and the threat of a latent TSE epidemic. This precedent raises the real possibility of other TSEs, like chronic wasting disease (CWD) of cervids, overcoming similar human transmission barriers. Early this year Canada reported its first case of BSE in over a decade audits first case of CWD in farmed elk in three years, underscoring the need for continued vigilance and research. Identifying mechanisms of transmission and zoonoses remains an extremely important and intense area of research that will benefit human and other animal populations.
PMCA Detection of CWD Infection in Cervid and Non-Cervid Species
Hoover, Edward Arthur
Colorado State University-Fort Collins, Fort Collins, CO, United States
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).***
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.
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.***
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.
Yet, it has to be noted that our assessments of PrPTSE levels in skeletal muscles were based on findings in presumably pre- or subclinically infected animals. Therefore, the concentration of PrPTSE in skeletal muscles of WTD with clinically manifest CWD may possibly exceed our estimate which refers to clinically inconspicuous animals that are more likely to enter the human food chain. Our tissue blot findings in skeletal muscles from CWD-infected WTD would be consistent with an anterograde spread of CWD prions via motor nerve fibres to muscle tissue (figure 4A). Similar neural spreading pathways of muscle infection were previously found in hamsters orally challenged with scrapie [28] and suggested by the detection of PrPTSE in muscle fibres and muscle-associated nerve fascicles of clinically-ill non-human primates challenged with BSE prions [29]. Whether the absence of detectable PrPTSE in myofibers observed in our study is a specific feature of CWD in WTD, or was due to a pre- or subclinical stage of infection in the examined animals, remains to be established. In any case, our observations support previous findings suggesting the precautionary prevention of muscle tissue from CWD-infected WTD in the human diet, and highlight the need to comprehensively elucidate of whether CWD may be transmissible to humans. While the understanding of TSEs in cervids has made substantial progress during the past few years, the assessment and management of risks possibly emanating from prions in skeletal muscles of CWD-infected cervids requires further research.
Prions in Skeletal Muscles of Deer with Chronic Wasting Disease
Rachel C. Angers1,*, Shawn R. Browning1,*,†, Tanya S. Seward2, Christina J. Sigurdson4,‡, Michael W. Miller5, Edward A. Hoover4, Glenn C. Telling1,2,3,§ + Author Affiliations
1 Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536, USA. 2 Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA. 3 Department of Neurology, University of Kentucky, Lexington, KY 40536, USA. 4 Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA. 5 Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, CO 80526, USA. ↵§ To whom correspondence should be addressed. E-mail: gtell2@uky.edu ↵* These authors contributed equally to this work.
↵† Present address: Department of Infectology, Scripps Research Institute, 5353 Parkside Drive, RF-2, Jupiter, FL 33458, USA.
↵‡ Present address: Institute of Neuropathology, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland.
Abstract The emergence of chronic wasting disease (CWD) in deer and elk in an increasingly wide geographic area, as well as the interspecies transmission of bovine spongiform encephalopathy to humans in the form of variant Creutzfeldt Jakob disease, have raised concerns about the zoonotic potential of CWD. Because meat consumption is the most likely means of exposure, it is important to determine whether skeletal muscle of diseased cervids contains prion infectivity. Here bioassays in transgenic mice expressing cervid prion protein revealed the presence of infectious prions in skeletal muscles of CWD-infected deer, demonstrating that humans consuming or handling meat from CWD-infected deer are at risk to prion exposure.
Exotic Meats USA Announces Urgent Statewide Recall of Elk Tenderloin Because It May Contain Meat Derived From An Elk Confirmed To Have Chronic Wasting Disease
Contact: Exotic Meats USA 1-800-680-4375
FOR IMMEDIATE RELEASE -- February 9, 2009 -- Exotic Meats USA of San Antonio, TX is initiating a voluntary recall of Elk Tenderloin because it may contain meat derived from an elk confirmed to have Chronic Wasting Disease (CWD). The meat with production dates of December 29, 30 and 31, 2008 was purchased from Sierra Meat Company in Reno, NV. The infected elk came from Elk Farm LLC in Pine Island, MN and was among animals slaughtered and processed at USDA facility Noah’s Ark Processors LLC.
Chronic Wasting Disease (CWD) is a fatal brain and nervous system disease found in elk and deer. The disease is caused by an abnormally shaped protein called a prion, which can damage the brain and nerves of animals in the deer family. Currently, it is believed that the prion responsible for causing CWD in deer and elk is not capable of infecting humans who eat deer or elk contaminated with the prion, but the observation of animal-to-human transmission of other prion-mediated diseases, such as bovine spongiform encephalopathy (BSE), has raised a theoretical concern regarding the transmission of CWD from deer or elk to humans. At the present time, FDA believes the risk of becoming ill from eating CWD-positive elk or deer meat is remote. However, FDA strongly advises consumers to return the product to the place of purchase, rather than disposing of it themselves, due to environmental concerns.
Exotic Meats USA purchased 1 case of Elk Tenderloins weighing 16.9 lbs. The Elk Tenderloin was sold from January 16 – 27, 2009. The Elk Tenderloins was packaged in individual vacuum packs weighing approximately 3 pounds each. A total of six packs of the Elk Tenderloins were sold to the public at the Exotic Meats USA retail store. Consumers who still have the Elk Tenderloins should return the product to Exotic Meats USA at 1003 NE Loop 410, San Antonio, TX 78209. Customers with concerns or questions about the Voluntary Elk Recall can call 1-800-680-4375. The safety of our customer has always been and always will be our number one priority.
Exotic Meats USA requests that for those customers who have products with the production dates in question, do not consume or sell them and return them to the point of purchase. Customers should return the product to the vendor. The vendor should return it to the distributor and the distributor should work with the state to decide upon how best to dispose. If the consumer is disposing of the product he/she should consult with the local state EPA office.
#
COLORADO: Farmer's market meat recalled after testing positive for CWD
24.dec.08 9News.com Jeffrey Wolf
Elk meat that was sold at a farmer's market is being recalled because tests show it was infected with chronic wasting disease. The Boulder County Health Department and Colorado Department of Public Health and Environment issued the recall Wednesday after the meat was sold at the Boulder County Fairgrounds on Dec. 13. Although there isn't any human health risk connected with CWD, the recalled was issued as a precaution. About 15 elk were bought from a commercial ranch in Colorado in early December and processed at a licensed plant. All 15 were tested for CWD and one came up positive. The labeling on the product would have the following information: *Seller: High Wire Ranch *The type of cut: "chuck roast," "arm roast," "flat iron," "ribeye steak," "New York steak," "tenderloin," "sirloin tip roast," "medallions" or "ground meat." *Processor: Cedaredge Processing *The USDA triangle containing the number "34645" People with questions about this meat can contact John Pape, epidemiologist at the Colorado Department of Public Health and Environment at 303-692-2628.
COULD NOT FIND any warning or recalls on these two sites confirming their recall of CWD infected meat. ...TSS
Wednesday, April 06, 2011
Presence and Seeding Activity of Pathological Prion Protein (PrPTSE) in Skeletal Muscles of White-Tailed Deer Infected with Chronic Wasting Disease
Prion Infectivity in Fat of Deer with Chronic Wasting Disease
Brent Race,# Kimberly Meade-White,# Richard Race, and Bruce Chesebro* Rocky Mountain Laboratories, 903 South 4th Street, Hamilton, Montana 59840
Received 2 June 2009/ Accepted 24 June 2009
ABSTRACT Top ABSTRACT TEXT REFERENCES
Chronic wasting disease (CWD) is a neurodegenerative prion disease of cervids. Some animal prion diseases, such as bovine spongiform encephalopathy, can infect humans; however, human susceptibility to CWD is unknown. In ruminants, prion infectivity is found in central nervous system and lymphoid tissues, with smaller amounts in intestine and muscle. In mice, prion infectivity was recently detected in fat. Since ruminant fat is consumed by humans and fed to animals, we determined infectivity titers in fat from two CWD-infected deer. Deer fat devoid of muscle contained low levels of CWD infectivity and might be a risk factor for prion infection of other species.
snip...
The highest risk of human contact with CWD might be through exposure to high-titer CNS tissue through accidental skin cuts or corneal contact at the time of harvest and butchering. However, the likelihood of a human consuming fat infected with a low titer of the CWD agent is much higher. It is impossible to remove all the fat present within muscle tissue, and fat consumption is inevitable when eating meat. Of additional concern is the fact that meat from an individual deer harvested by a hunter is typically consumed over multiple meals by the same group of people. These individuals would thus have multiple exposures to the CWD agent over time, which might increase the chance for transfer of infection.
In the Rocky Mountain region of North America, wild deer are subject to predation by wolves, coyotes, bears, and mountain lions. Although canines such as wolves and coyotes are not known to be susceptible to prion diseases, felines definitely are susceptible to BSE (9) and might also be infected by the CWD agent. Deer infected with the CWD agent are more likely to be killed by predators such as mountain lions (11). Peripheral tissues, including lymph nodes, muscle, and fat, which harbor prion infectivity are more accessible for consumption than CNS tissue, which has the highest level of infectivity late in disease. Therefore, infectivity in these peripheral tissues may be important in potential cross-species CWD transmissions in the wild.
The present finding of CWD infectivity in deer fat tissue raises the possibility that prion infectivity might also be found in fat tissue of other infected ruminants, such as sheep and cattle, whose fat and muscle tissues are more widely distributed in both the human and domestic-animal food chains. Although the infectivity in fat tissues is low compared to that in the CNS, there may be significant differences among species and between prion strains. Two fat samples from BSE agent-infected cattle were reported to be negative by bioassay in nontransgenic RIII mice (3, 6). However, RIII mice are 10,000-fold-less sensitive to BSE agent infection than transgenic mice expressing bovine PrP (4). It would be prudent to carry out additional infectivity assays on fat from BSE agent-infected cattle and scrapie agent-infected sheep using appropriate transgenic mice or homologous species to determine the risk from these sources.
*** 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 ;
TUESDAY, MARCH 28, 2017
*** Passage of scrapie to deer results in a new phenotype upon return passage to sheep ***
MONDAY, MARCH 13, 2017
CHRONIC WASTING DISEASE CWD TSE PRION UDATE March 13, 2017
SATURDAY, JANUARY 14, 2017
CHRONIC WASTING DISEASE CWD TSE PRION GLOBAL UPDATE JANUARY 14, 2017
In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible. For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.
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Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.
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What is the risk of chronic wasting disease being introduced into Great Britain? A Qualitative Risk Assessment October 2012
Thursday, April 07, 2016
What is the risk of chronic wasting disease being introduced into Great Britain? An updated Qualitative Risk Assessment March 2016
Subject: DEFRA What is the risk of a cervid TSE being introduced from Norway into Great Britain? Qualitative Risk Assessment September 2016
Friday, September 30, 2016
DEFRA What is the risk of a cervid TSE being introduced from Norway into Great Britain? Qualitative Risk Assessment September 2016
Scientific Opinion
Chronic wasting disease (CWD) in cervids
Authors
EFSA Panel on Biological Hazards (BIOHAZ),
First published: 18 January 2017Full publication history
DOI: 10.2903/j.efsa.2017.4667View/save citation
TUESDAY, JUNE 20, 2017
Norway Confirms 6th Case of Skrantesjuke CWD TSE Prion Disease
Tuesday, December 13, 2016
Norway Chronic Wasting Disease CWD TSE Prion disease Skrantesjuke December 2016 Update
Thursday, September 22, 2016
NORWAY DETECTS 5TH CASE OF CHRONIC WASTING DISEASE CWD TSE PRION Skrantesjuke
Saturday, September 03, 2016
NORWAY Regulation concerning temporary measures to reduce the spread of Chronic Wasting Disease (CWD) as 4th case of skrantesjuke confirmed in Sogn og Fjordane
Wednesday, August 31, 2016
*** NORWAY CONFIRMS 4TH CASE OF CHRONIC WASTING DISEASE CWD TSE PRION IN SECOND CARIBOU
Wednesday, August 31, 2016
NORWAY CONFIRMS 4TH CASE OF CHRONIC WASTING DISEASE CWD TSE PRION IN SECOND CARIBOU
Tuesday, August 02, 2016
Chronic wasting disease of deer – is the battle to keep Europe free already lost?
Tuesday, June 14, 2016
*** Chronic Wasting Disease (CWD) in a moose from Selbu in Sør-Trøndelag Norway ***
Thursday, July 07, 2016
Norway reports a third case Chronic Wasting Disease CWD TSE Prion in 2nd Norwegian moose
14/06/2016 - Norway reports a third case
Saturday, July 16, 2016
Chronic wasting Disease in Deer (CWD or Spongiform Encephalopathy) The British Deer Society 07/04/2016
Red Deer Ataxia or Chronic Wasting Disease CWD TSE PRION?
could this have been cwd in the UK back in 1970’S ???
SEE FULL TEXT ;
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.
***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.
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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.
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
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.
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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
MONDAY, JUNE 12, 2017
Rethinking Major grain organizations opposition to CFIA's control zone approach to Chronic Wasting CWD TSE Prion Mad Deer Type Disease 2017?
WEDNESDAY, MAY 17, 2017
*** Chronic Wasting Disease CWD TSE Prion aka Mad Deer Disease and the Real Estate Market Land Values ***
WEDNESDAY, JULY 26, 2017
*** Chronic wasting disease continues to spread Disease of cervids causing local population declines
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. ...
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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...
TUESDAY, JULY 18, 2017
MINK FARMING USA TRANSMISSIBLE MINK ENCEPHALOPATHY TSE PRION DISEASE SURVEILLANCE AND TESTING
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 its 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.
TUESDAY, JULY 18, 2017
USDA announces Alabama case of Bovine Spongiform Encephalopathy Alabama
THURSDAY, JULY 20, 2017
USDA OIE Alabama Atypical L-type BASE Bovine Spongiform Encephalopathy BSE animal feeds for ruminants rule, 21 CFR 589.200
SUNDAY, JULY 23, 2017
atypical L-type BASE Bovine Amyloidotic Spongiform Encephalopathy BSE TSE PRION
SUNDAY, JULY 23, 2017
Experimental Infection of Cattle With a Novel Prion Derived From Atypical H-Type Bovine Spongiform Encephalopathy
THURSDAY, JULY 13, 2017
EFSA BSE Sixty cases of mad cow disease since 2001 breached feed ban likely the cause
Scientists investigate origin of isolated BSE cases
MONDAY, JULY 17, 2017
National Scrapie Eradication Program May 2017 Monthly Report Fiscal Year 2017
WEDNESDAY, JULY 26, 2017
*** APHIS USDA Emerging Animal Disease Preparedness and Response Plan July 2017
FRIDAY, JULY 28, 2017
Korean government should suspend the import of U.S. beef by amending terms of trade
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.***
Friday, January 10, 2014
vpspr, sgss, sffi, TSE, an iatrogenic by-product of gss, ffi, familial type prion disease, what it ???
THURSDAY, JULY 13, 2017
TEXAS CREUTZFELDT JAKOB DISEASE CJD TSE PRION
National Prion Center could lose all funding just as concern about CWD jumping to humans rises
SATURDAY, JULY 15, 2017
*** National Prion Center could lose all funding just as concern about CWD jumping to humans rises
SATURDAY, JULY 22, 2017
Why the U.S. Needs to Continue Prion Disease Surveillance, instead of reducing funding to zero
TSS
posted by Terry S. Singeltary Sr. at
3:53 PM
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