cwd zoonosis, and the science there from of late...as follows;
*** WDA 2016 NEW YORK ***
We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions.
Student Presentations Session 2
The species barriers and public health threat of CWD and BSE prions
Ms. Kristen Davenport1, Dr. Davin Henderson1, Dr. Candace Mathiason1, Dr. Edward Hoover1 1Colorado State University
Chronic wasting disease (CWD) is spreading rapidly through cervid populations in the USA. Bovine spongiform encephalopathy (BSE, mad cow disease) arose in the 1980s because cattle were fed recycled animal protein. These and other prion diseases are caused by abnormal folding of the normal prion protein (PrP) into a disease causing form (PrPd), which is pathogenic to nervous system cells and can cause subsequent PrP to misfold. CWD spreads among cervids very efficiently, but it has not yet infected humans. On the other hand, BSE was spread only when cattle consumed infected bovine or ovine tissue, but did infect humans and other species. The objective of this research is to understand the role of PrP structure in cross-species infection by CWD and BSE. To study the propensity of each species’ PrP to be induced to misfold by the presence of PrPd from verious species, we have used an in vitro system that permits detection of PrPd in real-time. We measured the conversion efficiency of various combinations of PrPd seeds and PrP substrate combinations. We observed the cross-species behavior of CWD and BSE, in addition to feline-adapted CWD and BSE. We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions. CWD is unique among prion diseases in its rapid spread in natural populations. BSE prions are essentially unaltered upon passage to a new species, while CWD adapts to the new species. This adaptation has consequences for surveillance of humans exposed to CWD.
Wildlife Disease Risk Communication Research Contributes to Wildlife Trust Administration Exploring perceptions about chronic wasting disease risks among wildlife and agriculture professionals and stakeholders
PRION 2016 TOKYO
Zoonotic Potential of CWD Prions: An Update
Ignazio Cali1, Liuting Qing1, Jue Yuan1, Shenghai Huang2, Diane Kofskey1,3, Nicholas Maurer1, Debbie McKenzie4, Jiri Safar1,3,5, Wenquan Zou1,3,5,6, Pierluigi Gambetti1, Qingzhong Kong1,5,6 1Department of Pathology, 3National Prion Disease Pathology Surveillance Center, 5Department of Neurology, 6National Center for Regenerative Medicine, Case Western Reserve University, Cleveland, OH 44106, USA. 4Department of Biological Sciences and Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada, 2Encore Health Resources, 1331 Lamar St, Houston, TX 77010
Chronic wasting disease (CWD) is a widespread and highly transmissible prion disease in free-ranging and captive cervid species in North America. The zoonotic potential of CWD prions is a serious public health concern, but the susceptibility of human CNS and peripheral organs to CWD prions remains largely unresolved. We reported earlier that peripheral and CNS infections were detected in transgenic mice expressing human PrP129M or PrP129V. Here we will present an update on this project, including evidence for strain dependence and influence of cervid PrP polymorphisms on CWD zoonosis as well as the characteristics of experimental human CWD prions.
PRION 2016 TOKYO In Conjunction with Asia Pacific Prion Symposium 2016 PRION 2016 Tokyo Prion 2016
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
Saturday, April 23, 2016
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
Taylor & Francis
Prion 2016 Animal Prion Disease Workshop Abstracts
WS-01: Prion diseases in animals and zoonotic potential
Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a. Vincent Beringue c. Patricia Aguilar a,
Natalia Fernandez-Borges a. and Alba Marin-Moreno a
"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos, Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT. Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas. France
Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD) disease in human. To date, BSE agent is the only recognized zoonotic prion. Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that have been circulating for centuries in farmed ruminants there is no apparent epidemiological link between exposure to ruminant products and the occurrence of other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD). However, the zoonotic potential of the diversity of circulating TSE agents has never been systematically assessed. The major issue in experimental assessment of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the biological phenomenon that limits TSE agents’ propagation from a species to another. In the last decade, mice genetically engineered to express normal forms of the human prion protein has proved essential in studying human prions pathogenesis and modeling the capacity of TSEs to cross the human species barrier.
To assess the zoonotic potential of prions circulating in farmed ruminants, we study their transmission ability in transgenic mice expressing human PrPC (HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC (129Met or 129Val) are used to determine the role of the Met129Val dimorphism in susceptibility/resistance to the different agents.
These transmission experiments confirm the ability of BSE prions to propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be susceptible to BSE in sheep or goat to a greater degree than the BSE agent in cattle and that these agents can convey molecular properties and neuropathological indistinguishable from vCJD. However homozygous 129V mice are resistant to all tested BSE derived prions independently of the originating species suggesting a higher transmission barrier for 129V-PrP variant.
Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with ef?ciency comparable to that of cattle BSE. While the ef?ciency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
Title: Transmission of scrapie prions to primate after an extended silent incubation period)
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.
THIS SHOULD BE VERY IMPORTANT TO ALL CATTLE RANCHERS, BEEF PRODUCERS, AND OR DAIRY FARMERS
2016 Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
V. Use in animal feed of material from deer and elk NOT considered at high risk for CWD FDA continues to consider materials from deer and elk NOT considered at high risk for CWD to be acceptable for use in NON-RUMINANT animal feeds in accordance with current agency regulations, 21 CFR 589.2000. Deer and elk not considered at high risk include: (1) deer and elk from areas not declared by State officials to be endemic for CWD and/or to be CWD eradication zones; and (2) deer and elk that were not at some time during the 60-month period immediately before the time of slaughter in a captive herd that contained a CWD-positive animal.
SNIP...
Greetings again FDA and Mr. Pritchett et al,
MY comments and source reference of sound science on this very important issue are as follows ;
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
I kindly wish to once again submit to Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed.
Thank you kindly for allowing me to comment again, ...and again...and again, on a topic so important, why it is ‘NON-BINDING’ is beyond me.
this should have been finalized and made ‘BINDING’ or MANDATORY OVER A DECADE AGO.
but here lay the problem, once made ‘BINDING’ or ‘MANDATORY’, it is still nothing but ink on paper.
we have had a mad cow feed ban in place since August 1997, and since then, literally 100s of millions of pounds BANNED MAD COW FEED has been sent out to commerce and fed out (see reference materials).
ENFORCEMENT OF SAID BINDING REGULATIONS HAS FAILED US TOO MANY TIMES.
so, in my opinion, any non-binding or voluntary regulations will not work, and to state further, ‘BINDING’ or MANDATORY regulations will not work unless enforced.
with that said, we know that Chronic Wasting Disease CWD TSE Prion easily transmits to other cervid through the oral route.
the old transmission studies of BSE TSE floored scientist once they figured out what they had, and please don’t forget about those mink that were fed 95%+ dead stock downer cow, that all came down with TME. please see ;
It is clear that the designing scientists must also have shared Mr Bradleys surprise at the results because all the dose levels right down to 1 gram triggered infection.
http://web.archive.org/web/20061003022720/http://www.bseinquiry.gov.uk/files/ws/s145d.pdf
Evidence That Transmissible Mink Encephalopathy Results from Feeding Infected Cattle
Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.
snip...
The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...
To further complicate things, we now know that science has shown that plants and vegetables can uptake the TSE Prion, and that the Scrapie agent can still be infectious from soil 16 years later. a frightening thought with the CWD running rampant now in North America (please see source reference materials below).
IF we don’t do this, we have failed, and the TSE Prion agent will continue to spread, as it is doing as we speak.
I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids, as well as non-ruminants such as cats and dogs as well, as soon as possible for the following reasons...
Sunday, March 20, 2016
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
Singeltary previous submission to DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability
DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability Fri, 16 May 2003 11:47:37 0500 EMC 1 Terry S. Singeltary Sr. Vol #: 1
Date: Fri, 16 May 2003 11:47:37 0500 EMC 1 Terry S. Singeltary Sr. Vol #: 1
MARCH 1, 2011
UPDATED CORRESPONDENCE FROM AUTHORS OF THIS STUDY I.E. COLBY, PRUSINER ET AL, ABOUT MY CONCERNS OF THE DISCREPANCY BETWEEN THEIR FIGURES AND MY FIGURES OF THE STUDIES ON CWD TRANSMISSION TO CATTLE ;
----- Original Message -----
From: David Colby
To: flounder9@verizon.net
Cc: stanley@XXXXXXXX
Sent: Tuesday, March 01, 2011 8:25 AM
Subject: Re: FW: re-Prions David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations
Dear Terry Singeltary,
Thank you for your correspondence regarding the review article Stanley Prusiner and I recently wrote for Cold Spring Harbor Perspectives. Dr. Prusiner asked that I reply to your message due to his busy schedule. We agree that the transmission of CWD prions to beef livestock would be a troubling development and assessing that risk is important. In our article, we cite a peer-reviewed publication reporting confirmed cases of laboratory transmission based on stringent criteria. The less stringent criteria for transmission described in the abstract you refer to lead to the discrepancy between your numbers and ours and thus the interpretation of the transmission rate. We stand by our assessment of the literature--namely that the transmission rate of CWD to bovines appears relatively low, but we recognize that even a low transmission rate could have important implications for public health and we thank you for bringing attention to this matter.
Warm Regards, David Colby
--
David Colby, PhDAssistant ProfessorDepartment of Chemical EngineeringUniversity of Delaware
====================END...TSS==============
SNIP...SEE FULL TEXT ;
http://betaamyloidcjd.blogspot.com/2011/01/enlarging-spectrum-of-prion-like.html
Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies Location: Virus and Prion Diseases of Livestock
Title: TRANSMISSION OF CHRONIC WASTING DISEASE AGENT OF MULE DEER (CWD**MD) TO SUFFOLK SHEEP BY INTRACEREBRAL ROUTE
Authors
Hamir, Amirali Kunkle, Robert Cutlip, Randall - ARS RETIRED Miller, Janice - ARS RETIRED Williams, Elizabeth - UNIVERSITY OF WYOMING Richt, Juergen
Submitted to: European Society of Veterinary Pathology Publication Type: Abstract Publication Acceptance Date: June 5, 2006 Publication Date: August 31, 2006
Citation: Hamir, A., Kunkle, R., Cutlip, R., Miller, J., Williams, E., Richt, J. 2006.
Transmission of chronic wasting disease agent of mule deer (CWD**md) to Suffolk sheep by intracerebral route [abstract]. European Society of Veterinary Pathology 24th Annual Meeting. Paper No. P63. p. 171-172.
Technical Abstract: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that has been identified in captive and free-ranging cervids in the U.S. since 1967. To determine the transmissibility of CWD to sheep, 8 Suffolk lambs [4 QQ and 4 QR at codon 171 of prion protein (PRNP) gene] were inoculated intracerebrally with a pooled brain suspension from 28 mule deer naturally affected with CWD (CWD**md). Two other lambs (1 QQ and 1 QR at codon 171 of the PRNP gene) were kept as non-inoculated controls. Within 36 months post inoculation (MPI), 2 animals became sick and were euthanized. Only 1 sheep (euthanized at 35 MPI) showed clinical signs that were consistent with those described for scrapie. Microscopic lesions of spongiform encephalopathy (SE) were only seen in the sheep with the clinical signs of TSE and its tissues were positive for the abnormal prion protein (PrP**res) by immunohistochemistry and Western blot. Between 36 and 60 MPI, 3 other sheep were euthanized because of conditions unrelated to TSE. The remaining 3 sheep remained non-clinical at the termination of the study (72 MPI) and were euthanized at that time. One of the 3 animals revealed SE and its tissues were positive for PrP**res. Both sheep positive for PrP**res were homozygous QQ at codon 171. Retrospective examination of the PRNP genotype of the 2 TSE-positive animals revealed that the sheep with clinical prion disease (euthanized at 35 MPI) was heterozygous (AV) and the sheep with the sub-clinical disease (euthanized at 72 MPI) was homozygous (AA) at codon 136 of the PRNP. These findings demonstrate that transmission of the CWD**md agent to sheep via the intracerebral route is possible. Interestingly, the host genotype may play a significant part in successful transmission and incubation period of CWD**md.
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=194075
Transmission of chronic wasting disease of mule deer to Suffolk sheep following intracerebral inoculation
Amir N. Hamir,1 Robert A. Kunkle, Randall C. Cutlip, Janice M. Miller, Elizabeth S. Williams, Juergen A. Richt
Abstract. To determine the transmissibility of chronic wasting disease (CWD) to sheep, 8 Suffolk lambs of various prion protein genotypes (4 ARQ/ARR, 3 ARQ/ARQ, 1 ARQ/VRQ at codons 136, 154, and 171, respectively) were inoculated intracerebrally with brain suspension from mule deer with CWD (CWDmd). Two other lambs were kept as noninoculated controls. Within 36 months postinoculation (MPI), 2 inoculated animals became sick and were euthanized. Only 1 sheep (euthanized at 35 MPI) showed clinical signs that were consistent with those described for scrapie. Microscopic lesions of spongiform encephalopathy (SE) were only seen in this sheep, and its tissues were determined to be positive for the abnormal prion protein (PrPres) by immunohistochemistry and Western blot. Three other inoculated sheep were euthanized (36 to 60 MPI) because of conditions unrelated to TSE. The 3 remaining inoculated sheep and the 2 control sheep did not have clinical signs of disease at the termination of the study (72 MPI) and were euthanized. Of the 3 remaining inoculated sheep, 1 was found to have SE, and its tissues were positive for PrPres. The sheep with clinical prion disease (euthanized at 35 MPI) was of the heterozygous genotype (ARQ/VRQ), and the sheep with subclinical disease (euthanized at 72 MPH) was of the homozygous ARQ/ARQ genotype. These findings demonstrate that transmission of the CWDmd agent to sheep via the intracerebral route is possible. Interestingly, the host genotype may play a notable part in successful transmission and incubation period of CWDmd.
snip...
Thus far, among domestic animals, CWDmd has been transmitted by the intracerebral route to a goat18 and cattle.5–7 The present findings demonstrate that it is also possible to transmit CWDmd agent to sheep via the intracerebral route. However, the only sheep to develop clinical TSE within 35 MPI was genotypically AV at PRNP codon 136, suggesting that host genotype may play a notable part in successful transmission of the disease in this species. Although in Suffolk sheep the AV variant at codon 136 is very rare,17 selective breeding of Suffolk sheep with this codon has begun in the hope of testing this differential susceptibility hypothesis in a future study of CWDmd transmission to sheep.
Key words: Chronic wasting disease; immunohistochemistry; intracerebral transmission; prion protein; sheep; spongiform encephalopathy.
http://vdi.sagepub.com/content/18/6/558.long
Research Project: Transmission, Differentiation, and Pathobiology of Transmissible Spongiform Encephalopathies Location: Virus and Prion Diseases of Livestock
Title: EXPERIMENTAL SECOND PASSAGE OF CHRONIC WASTING DISEASE (CWD(MULE DEER)) AGENT TO CATTLE
Authors
Hamir, Amirali Kunkle, Robert Miller, Janice - ARS RETIRED Greenlee, Justin Richt, Juergen
Submitted to: Journal of Comparative Pathology Publication Type: Peer Reviewed Journal Publication Acceptance Date: July 25, 2005 Publication Date: January 1, 2006 Citation: Hamir, A.N., Kunkle, R.A., Miller, J.M., Greenlee, J.J., Richt, J.A. 2006.
Experimental second passage of chronic wasting disease (CWD(mule deer)) agent to cattle. Journal of Comparative Pathology. 134(1):63-69.
Interpretive Summary: To compare the findings of experimental first and second passage of chronic wasting disease (CWD) in cattle, 6 calves were inoculated into the brain with CWD-mule deer agent previously (first) passaged in cattle. Two other uninoculated calves served as controls. Beginning 10-12 months post inoculation (PI), all inoculates lost appetite and weight. Five animals subsequently developed clinical signs of central nervous system (CNS) abnormality. By 16.5 months PI, all cattle had been euthanized because of poor prognosis. None of the animals showed microscopic lesions of spongiform encephalopathy (SE) but the CWD agent was detected in their CNS tissues by 2 laboratory techniques (IHC and WB). These findings demonstrate that inoculated cattle amplify CWD agent but also develop clinical CNS signs without manifestation of microscopic lesions of SE. This situation has also been shown to occur following inoculation of cattle with another TSE agent, namely, sheep scrapie. The current study confirms previous work that indicates that the diagnostic tests currently used for confirmation of bovine spongiform encephalopathy (BSE) in the U.S. would detect CWD in cattle, should it occur naturally. Furthermore, it raises the possibility of distinguishing CWD from BSE in cattle due to the absence of microscopic lesions and a unique multifocal distribution of PrPres, as demonstrated by IHC, which in this study, appears to be more sensitive than the WB.
Technical Abstract: To compare clinicopathological findings of first and second passage of chronic wasting disease (CWD) in cattle, a group of calves (n=6) were intracerebrally inoculated with CWD-mule deer agent previously (first) passaged in cattle. Two other uninoculated calves served as controls. Beginning 10-12 months post inoculation (PI), all inoculates lost appetite and lost weight. Five animals subsequently developed clinical signs of central nervous system (CNS) abnormality. By 16.5 months PI, all cattle had been euthanized because of poor prognosis. None of the animals showed microscopic lesions of spongiform encephalopathy (SE) but PrPres was detected in their CNS tissues by immunohistochemistry (IHC) and Western blot (WB) techniques. These findings demonstrate that intracerebrally inoculated cattle not only amplify CWD PrPres but also develop clinical CNS signs without manifestation of morphologic lesions of SE. This situation has also been shown to occur following inoculation of cattle with another TSE agent, scrapie. The current study confirms previous work that indicates the diagnostic techniques currently used for confirmation of bovine spongiform encephalopathy (BSE) in the U.S. would detect CWD in cattle, should it occur naturally. Furthermore, it raises the possibility of distinguishing CWD from BSE in cattle due to the absence of neuropathologic lesions and a unique multifocal distribution of PrPres, as demonstrated by IHC, which in this study, appears to be more sensitive than the WB.
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=178318
WS-02
Scrapie in swine: A diagnostic challenge
Justin J Greenlee1, Robert A Kunkle1, Jodi D Smith1, Heather W. Greenlee2
1National Animal Disease Center, US Dept. of Agriculture, Agricultural Research Service, United States; 2Iowa State University College of Veterinary Medicine
A naturally occurring prion disease has not been recognized in swine, but the agent of bovine spongiform encephalopathy does transmit to swine by experimental routes. Swine are thought to have a robust species barrier when exposed to the naturally occurring prion diseases of other species, but the susceptibility of swine to the agent of sheep scrapie has not been thoroughly tested.
Since swine can be fed rations containing ruminant derived components in the United States and many other countries, we conducted this experiment to test the susceptibility of swine to U.S. scrapie isolates by intracranial and oral inoculation. Scrapie inoculum was a pooled 10% (w/v) homogenate derived from the brains of clinically ill sheep from the 4th passage of a serial passage study of the U.S scrapie agent (No. 13-7) through susceptible sheep that were homozygous ARQ at prion protein residues 136, 154, and 171, respectively. Pigs were inoculated intracranially (n=19) with a single 0.75 ml dose or orally (n=24) with 15 ml repeated on 4 consecutive days. Necropsies were done on a subset of animals at approximately six months post inoculation (PI), at the time the pigs were expected to reach market weight. Remaining pigs were maintained and monitored for clinical signs of TSE until study termination at 80 months PI or when removed due to intercurrent disease (primarily lameness). Brain samples were examined by immunohistochemistry (IHC), western blot (WB), and enzyme-linked immunosorbent assay (ELISA). Brain tissue from a subset of pigs in each inoculation group was used for bioassay in mice expressing porcine PRNP.
At six-months PI, no evidence of scrapie infection was noted by any diagnostic method. However, at 51 months of incubation or greater, 5 animals were positive by one or more methods: IHC (n=4), WB (n=3), or ELISA (n=5). Interestingly, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study).
Swine inoculated with the agent of scrapie by the intracranial and oral routes do not accumulate abnormal prion protein (PrPSc) to a level detectable by IHC or WB by the time they reach typical market age and weight. However, strong support for the fact that swine are potential hosts for the agent of scrapie comes from positive bioassay from both intracranially and orally inoculated pigs and multiple diagnostic methods demonstrating abnormal prion protein in intracranially inoculated pigs with long incubation times.
Curriculum Vitae
Dr. Greenlee is Research Veterinary Medical Officer in the Virus and Prion Research Unit at the National Animal Disease Center, US Department of Agriculture, Agricultural Research Service. He applies his specialty in veterinary anatomic pathology to focused research on the intra- and interspecies transmission of prion diseases in livestock and the development of antemortem diagnostic assays for prion diseases. In addition, knockout and transgenic mouse models are used to complement ongoing experiments in livestock species. Dr. Greenlee has publications in a number of topic areas including prion agent decontamination, effects of PRNP genotype on susceptibility to the agent of sheep scrapie, characterization of US scrapie strains, transmission of chronic wasting disease to cervids and cattle, features of H-BSE associated with the E211 K polymorphism, and the development of retinal assessment for antemortem screening for prion diseases in sheep and cattle. Dr. Greenlee obtained his DVM degree and completed the PhD/residency program in Veterinary Pathology at Iowa State University. He is a Diplomate of the American College of Veterinary Pathologists.
http://prion2016.org
***In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006). It is not known how susceptible humans are to CWD but given that the prion can be present in muscle, it is likely that humans have been exposed to the agent via consumption of venison (Sigurdson, 2008). Initial experimental research, however, suggests that human susceptibility to CWD is low and there may be a robust species barrier for CWD transmission to humans (Sigurdson, 2008). It is apparent, though, that CWD is affecting wild and farmed cervid populations in endemic areas with some deer populations decreasing as a result.
Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle
Authors: Nicholas Haley1, Christopher Siepker2, Justin Greenlee3, Jürgen Richt4
VIEW AFFILIATIONS Affiliations: 1 1Midwestern Univerisity 2 2Kansas State University 3 3USDA, Agricultural Research Service 4 4Kansas State University
Published Ahead of Print: 31 March, 2016 Journal of General Virology doi: 10.1099/jgv.0.000438 Published Online: 31/03/2016
Chronic wasting disease (CWD) is a fatal neurodegenerative disease, classified as a prion disease or transmissible spongiform encephalopathy (TSE) similar to bovine spongiform encephalopathy (BSE). Cervids affected by CWD accumulate an abnormal protease resistant prion protein throughout the central nervous system (CNS), as well as in both lymphatic and excretory tissues - an aspect of prion disease pathogenesis not observed in cattle with BSE. Using seeded amplification through real time quaking induced conversion (RT-QuIC), we investigated whether the bovine host or prion agent was responsible for this aspect of TSE pathogenesis. We blindly examined numerous central and peripheral tissues from cattle inoculated with CWD for prion seeding activity. Seeded amplification was readily detected in the CNS, though rarely observed in peripheral tissues, with a limited distribution similar to that of BSE prions in cattle. This seems to indicate that prion peripheralization in cattle is a host-driven characteristic of TSE infection.
Friday, August 14, 2015
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
ARS VIRUS AND PRION RESEARCH / Research / Publication #277212
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Title: Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
Authors
item Greenlee, Justin item Nicholson, Eric item Smith, Jodi item Kunkle, Robert item Hamir, Amirali
Submitted to: Journal of Veterinary Diagnostic Investigation Publication
Type: Peer Reviewed Journal Publication Acceptance
Date: July 12, 2012
Publication Date: November 1, 2012
Citation: Greenlee, J.J., Nicholson, E.M., Smith, J.D., Kunkle, R.A., Hamir, A.N. 2012.
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation.
Journal of Veterinary Diagnostic Investigation. 24(6):1087-1093.
Interpretive Summary: Chronic Wasting Disease (CWD), a fatal neurodegenerative disease that occurs in farmed and wild cervids (deer and elk) of North America, is a transmissible spongiform encephalopathy (TSE). TSEs are caused by infectious proteins called prions that are resistant to various methods of decontamination and environmental degradation. Cattle could be exposed to chronic wasting disease (CWD) by contact with infected farmed or free-ranging cervids. The purpose of this study was to assess the potential transmission of CWD from elk to cattle after intracranial inoculation, the most direct route to test the potential of a host to replicate an isolate of the prion agent. This study reports that only 2 of 14 calves inoculated with CWD from elk had clinical signs or evidence of abnormal prion protein accumulation. These results suggest that cattle are unlikely to be susceptible to CWD if inoculated by a more natural route. This information could have an impact on regulatory officials developing plans to reduce or eliminate TSEs and farmers with concerns about ranging cattle on areas where CWD may be present.
Technical Abstract:
***Cattle could be exposed to the agent of chronic wasting disease (CWD) through contact with infected farmed or free-ranging cervids or exposure to contaminated premises. The purpose of this study was to assess the potential for CWD derived from elk to transmit to cattle after intracranial inoculation. Calves (n=14) were inoculated with brain homogenate derived from elk with CWD to determine the potential for transmission and define the clinicopathologic features of disease.
Cattle were necropsied if clinical signs occurred or at the termination of experiment (49 months post-inoculation (MPI)).
Clinical signs of poor appetite, weight loss, circling, and bruxism occurred in two cattle (14%) at 16 and 17 MPI, respectively.
Accumulation of abnormal prion protein (PrP**Sc) in these cattle was confined to the central nervous system with the most prominent immunoreactivity in midbrain, brainstem, and hippocampus with lesser immunoreactivity in the cervical spinal cord.
*** The rate of transmission was lower than in cattle inoculated with CWD derived from mule deer (38%) or white-tailed deer (86%).
Additional studies are required to fully assess the potential for cattle to develop CWD through a more natural route of exposure, but a low rate of transmission after intracranial inoculation suggests that risk of transmission through other routes is low.
***A critical finding here is that if CWD did transmit to exposed cattle, currently used diagnostic techniques would detect and differentiate it from other prion diseases in cattle based on absence of spongiform change, distinct pattern of PrP**Sc deposition, and unique molecular profile.
Monday, April 04, 2016
*** Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle ***
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