Texas Chronic Wasting Disease Detected in Medina County Deer Breeding Facility
Chronic Wasting Disease Detected in Medina County Deer Breeding Facility
Oct. 24, 2023
Media Contact: TPWD News, Business Hours, 512-389-8030
AUSTIN — The Texas Parks and Wildlife Department (TPWD) received confirmation of a case of chronic wasting disease (CWD) in Medina County, marking the fifth detection since 2015 in a deer-breeding facility in the county.
A one-year-old buck tested positive through an antemortem (live-animal) test conducted to meet annual CWD surveillance requirements for the facility.
Wisconsin Veterinary Diagnostic Lab initially analyzed the samples, and the National Veterinary Services Laboratory in Iowa confirmed the CWD detection.
CWD has an incubation period that can span years, so the first indication of the disease in a herd is often found through surveillance testing rather than observed clinical signs. Early detection and proactive monitoring improve the state’s response time to the detection of CWD and can greatly reduce the risk of further disease spread.
Due to this recent detection, TPWD may establish a surveillance zone encompassing a two-mile radius. Any hunter harvesting a deer on a property that is wholly or partially encompassed by the zone will be subject to CWD zone rules. All hunter-harvested deer from this new zone must be presented at the Hondo check station location within 48 hours of harvesting the deer.
All affected landowners within this zone will be contacted by the department after the zone boundaries are established.
CWD is a fatal neurological disease found in certain cervids including deer, elk, moose and other members of the deer family. This slow, progressive disease may not produce visible signs in susceptible species for several years after infection. As the irreversible disease process continues, animals with CWD may show changes in behavior and appearance. Clinical signs may include progressive weight loss, stumbling or tremors with a lack of coordination, loss of appetite, teeth grinding, abnormal head posture and/or drooping ears, and excessive thirst, salivation or urination.
In Texas, the disease was first discovered in 2012 in free-ranging mule deer along a remote area of the Hueco Mountains near the Texas-New Mexico border. CWD has since been detected in Texas captive and free-ranging cervids, including white-tailed deer, mule deer, red deer and elk.
For more information on previous detections in Texas and CWD best management practices for hunters and landowners, visit TPWD’s CWD page. The recently updated page includes a map of all CWD zones, check stations and positive case tracking. This webpage can be utilized to find answers to frequently asked questions, view videos with information from wildlife veterinarians and review the latest news.
https://tpwd.texas.gov/newsmedia/releases/?req=20231024a
Please note, TPWD et al have stopped updating the TPWD CWD Tracking page, which has been stuck on 508 CWD cases to date since June of 2023, about 5 months ago, and i was told several months ago that figure was upwards 550+, so with cases since the, total Cwd in Texas must be pushing 600 CWD positives. For the TPWD et al to stop updating the CWD Tracking page total count, CWD in Texas must have exploded, imo…
Chronic Wasting Disease in Texas
A Real Disease with Proven Impacts
Produced by a coalition of concerned hunters, landowners, & conservationists (last update 08/2023)
Snip…
Since 2012, CWD has been detected in wild deer in just 7 counties in Texas and is only established in the western panhandle and far west Texas.
In that same period of time, captive deer breeders have exposed almost half of Texas counties to CWD.
Deer held in captive breeding facilities are confined to much tighter spaces, and have intimate contact with many more animals on a daily basis. By far the greatest factor in amplifying the spread of CWD is the artificial movement of these animals, shipped in livestock trailers hundreds of miles, far outside of their natural home range, and ultimately released to co-mingle with wild deer.
Each year, Texas captive deer breeders liberate 20,000-30,000 deer from their pens to the wild.
For every deer breeding facility where a CWD positive deer is discovered, an epidemiological investigation is conducted by the Texas Parks & Wildlife Department and the Texas Animal Health Commission to determine how many other deer may have been exposed to the disease and where they have been shipped. Because of the prolific artificial movement of captive deer, one deer with CWD can impact hundreds of other facilities and ranches across the state.
Unfortunately, released deer in Texas are not required to retain any kind of visible identification (an ear tag), and for this reason, the vast majority of released deer cannot be relocated for testing.
As of August 2023, 116 Texas counties have received possibly infected breeder deer that cannot be located, putting more than 140,000 landowners at risk of the disease.
Snip
The state of Texas has been testing for CWD since 2002. Since that time, more than 302,360 captive and free range deer have been tested.
From 2015-2022, more than 127,000 samples were collected from hunter-harvested and roadkill deer. This sampling rate and risk-based distribution provides scientists confidence that they would have detected the disease if it existed at a very low prevalence (<1%) in any given region at the time sampling began.
Snip…
We have learned from other states where CWD has been present the longest, that a constant increase in the prevalence of the disease may lead to a significant decline in the deer population. When disease prevalence exceeds 20%, deer populations have declined by up to 50%. In some areas of Colorado, where CWD has been present since 1985, mule deer abundance has declined by 45% since that time, despite adequate habitat and no hunting ( Miller et al. 2008 ). Similarly, the South Converse Game Unit in Wyoming has documented CWD prevalence exceeding 50% and has seen an approximate 50% decline in mule deer populations.
Snip…
Rural Economies
Deer hunting is the lifeblood of rural Texas. White-tailed deer hunting is by far the most impactful segment of the hunting economy, representing $4.3 billion, according to a recent Texas A&M Study. And while deer breeders represent a very small segment of that economy (less than 5%), they represent one of the greatest risks. ( Full Texas A&M Report )
Real Estate
Rural land prices are largely driven by recreational buyers with hunting as a top land amenity. Without deer hunting, many of these properties will be worth much less.
Conservation Funding
Deer hunters are the largest funders of wildlife conservation in Texas through excise taxes on firearms, ammunition, and gear along with active membership supporting and funding conservation organizations. If deer hunting suffers due to CWD, all wildlife in Texas lose.
Culture & Health
Texas’ native deer herd has iconic value for all Texans. Deer hunting brings families together, creates camaraderie in communities, and serves to connect Texans to nature. There is no better protein than wild, locally harvested, non-GMO and totally organic venison. A healthy deer herd leads to healthy Texans and a healthy and prosperous Texas.
Snip…
This isn't a disease for our lifetime. It's a disease for our grandchildren's lifetime.
- Dr. Bob Dittmar, Former Texas State Wildlife Veterinarian
Snip…
See the full text with maps, graphs, much more, excellent data…
Since 2012, CWD has been detected in wild deer in just 7 counties in Texas and is only established in the western panhandle and far west Texas.
In that same period of time, captive deer breeders have exposed almost half of Texas counties to CWD.
As of August 2023, 116 Texas counties have received possibly infected breeder deer that cannot be located, putting more than 140,000 landowners at risk of the disease.
Texas CWD Surveillance Positives
Counties where CWD Exposed Deer were Released
https://tpwd.texas.gov/documents/257/CWD-Trace-OutReleaseSites.pdf
Number of CWD Exposed Deer Released by County
https://tpwd.texas.gov/documents/258/CWD-Trace-OutReleaseSites-NbrDeer.pdf
Chronic Wasting Disease CWD Captive Herds updated April 2023
Chronic Wasting Disease CWD Captive Herds updated April 2023
https://www.aphis.usda.gov/animal_health/animal_diseases/cwd/downloads/status-of-captive-herds.pdf
TPWD Executive Order No. 23-003 CWD Emergency Rules Adopted for Movement of Breeder Deer
Executive Orders
2023
Executive Order No. 23-003
Date: July 24, 2023
The Executive Director finds that additional discoveries of CWD in free-ranging white-tailed deer within deer breeding facilities regulated under Parks and Wildlife Code, Chapter 43, Subchapter L and regulations adopted pursuant to that subchapter (31 TAC Chapter 65, Subchapters B and T) constitute an immediate danger to the white-tailed deer and mule deer resources of Texas and that the adoption of rules on an emergency basis with fewer than 30 days’ notice is necessary to address an immediate danger.
https://tpwd.texas.gov/publications/executive_orders/
15 minute mark video shows sick deer with cwd, and this deer DIED FROM CWD, IT'S DOCUMENTED, commentator says ''so if anyone every tells you, that a deer has never died from CWD, think of this picture, because the Wisconsin Veterinary Lab told us, what when they looked at her sample under a microscope, she was the hottest animal they had ever seen, and that's in terms of the fluorescents that comes off the slide when the look at it, so, a lot of Prion in her system.''
see much more about 2 hours long...
https://www.youtube.com/watch?v=O3CAI-EwlgM
TEXAS BREEDER DEER ESCAPEE WITH CWD IN THE WILD, or so the genetics would show?
OH NO, please tell me i heard this wrong, a potential Texas captive escapee with cwd in the wild, in an area with positive captive cwd herd?
apparently, no ID though. tell me it ain't so please...
23:00 minute mark
''Free Ranging Deer, Dr. Deyoung looked at Genetics of this free ranging deer and what he found was, that the genetics on this deer were more similar to captive deer, than the free ranging population, but he did not see a significant connection to any one captive facility that he analyzed, so we believe, Ahhhhhh, this animal had some captive ahhh, whatnot.''
https://youtu.be/aoPDeGL6mpQ?t=1384
Commission Agenda Item No. 5 Exhibit B
DISEASE DETECTION AND RESPONSE RULES
PROPOSAL PREAMBLE
1. Introduction.
snip...
A third issue is the accuracy of mortality reporting. Department records indicate that for each of the last five years an average of 26 deer breeders have reported a shared total of 159 escapes. Department records for the same time period indicate an average of 31 breeding facilities reported a shared total of 825 missing deer (deer that department records indicate should be present in the facility, but cannot be located or verified).
https://tpwd.texas.gov/business/feedback/meetings/2022/1104/agenda/item.phtml?item=5
On January 21, 2017 a tornado took down thousands of feet of fence for a 420-acre illegal deer enclosure in Lamar County that had been subject to federal and state investigation for illegally importing white-tailed deer into Mississippi from Texas (a CWD positive state). Native deer were free to move on and off the property before all of the deer were able to be tested for CWD. Testing will be made available for a period of three years for CWD on the property and will be available for deer killed within a 5-mile radius of the property on a voluntary basis.
https://www.mdwfp.com/media/254796/2016-17-deer-report.pdf
“It is interesting to note that, in 2001, the State of Texas shifted its deer management strategies toward the same leanings that Kroll has suggested for Wisconsin. In Texas, the change was brought about via heavy lobbying from the high-fence deer ranching industry. This pressure helped convince the Texas Parks and Wildlife to change their regulations and allow private landowners to select the own deer biologists.”
http://www.texasmonthly.com/story/which-side-fence-are-you
2012 “For 10 years, Texas has had an aggressive Chronic Wasting Disease prevention and monitoring program. Wildlife agency regulations prohibit importing deer into the state, and the agency has tested more than 26,000 hunter-taken deer and 7,400 animals from the captive-deer industry. None of those deer tested positive.”
http://www.chron.com/news/houston-texas/article/Brain-eating-disease-found-in-Texas-deer-3697731.php
"Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation."
Detection of prions in soils contaminated by multiple routes
Stuart Siegfried Lichtenberg1,2 , Heather Inzalaco3 , Sam Thomas4 , Dan Storm5 , Dan Walsh6
1Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, U.S.A. 2Minnesota Center for Prion Research and Outreach, University of Minnesota, St. Paul, Minnesota, U.S.A. 3 Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, U.S.A 4Department of Soil Science, University of Wisconsin-Madison, Madison, Wisconsin, U.S.A. 5Wisconsin Department of Natural Resources, Eau Claire, Wisconsin, U.S.A. 6U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, Montana, U.S.A.
Aims: Free-ranging animals afflicted with transmissible spongiform encephalopathies frequently shed infectious prions into the broader environment. The quintessential example is chronic wasting disease, the TSE of cervids. Over the course of the disease, an infected animal will shed infectious prions in blood, urine, saliva, and feces. Upon death, the total prion load interred in the animal’s tissues will be deposited wherever the animal falls. This contamination creates substantial risk to naïve animals, and likely contributes to disease spread. Identification and quantification of prions at contamination hotspots is essential for any attempt at mitigation of environmental transmission.
Materials and Methods: Surfactant extraction of soils followed by precipitation yields a sample that is amenable to analysis by real-time quaking induced conversion. However, differences in extraction yield are apparent depending on the properties of the matrix from which the prions are being extracted, principally soil clay content.
Results: We are able to detect prion seeding activity at multiple types of environmental hotspots, including carcass sites, contaminated captive facilities, and scrapes (i.e. urine and saliva). Differences in relative prion concentration vary depending on the nature and source of the contamination.
Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation.
Conclusions: Detection of prions in the environment is of the utmost importance for controlling chronic wasting disease spread. Here, we have demonstrated a viable method for detection of prions in complex environmental matrices. However, it is quite likely that this method underestimates the total infectious prion load in a contaminated sample, due to incomplete recovery of infectious prions. Further refinements are necessary for accurate quantification of prions in such samples, and to account for the intrinsic heterogeneities found in the broader environment.
Funded by: Wisconsin Department of Natural Resources
"Additionally, we have determined that prion seeding activity is retained for at least fifteen years at a contaminated site following attempted remediation."
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The detection and decontamination of chronic wasting disease prions during venison processing
Marissa S. Milstein1,2, Marc D. Schwabenlander1,2, Sarah C. Gresch1,2, Manci Li1,2, Stuart Lichtenberg1,2, Rachel Shoemaker1,2, Gage R. Rowden1,2, Jason C. Bartz2,3 , Tiffany M. Wolf2,4, Peter A. Larsen1,2
Presenting author: Tiffany M. Wolf 1 Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA 2 Minnesota Center for Prion Research and Outreach, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA 3 Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska, USA 4 Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA
Aims: There is a growing concern that chronic wasting disease (CWD) prions in venison pose a risk to human health. CWD prions accumulate in infected deer tissues that commonly enter the human food chain through meat processing and consumption. The United States (US) Food and Drug Administration and US Department of Agriculture now formally consider CWD-positive venison unfit for human and animal consumption. Yet, the degree to which prion contamination occurs during routine venison processing is unknown. Here, we use environmental surface swab methods to: a) experimentally test meat processing equipment (i.e., stainless steel knives and polyethylene cutting boards) before and after processing CWD-positive venison and b) test the efficacy of five different disinfectant types (i.e., Dawn dish soap, Virkon-S, Briotech, 10% bleach, and 40% bleach) to determine prion decontamination efficacy.
Materials and Methods: We used a real-time quaking-induced conversion (RT-QuIC) assay to determine CWD infection status of venison and to detect CWD prions in the swabs. We collected three swabs per surface and ran eight technical replicates on RT-QuIC.
Results: CWD prions were detected on all cutting boards (n= 3; replicates= 8/8, 8/8, 8/8 and knives (n= 3; replicates= 8/8, 8/8, 8/8) used in processing CWD-positive venison, but not on those used for CWD-negative venison. After processing CWD-positive venison, allowing the surfaces to dry, and washing the cutting board with Dawn dish soap, we detected CWD prions on the cutting board surface (n= 3; replicates= 8/8, 8/8, 8/8) but not on the knife (n= 3, replicates = 0/8, 0/8, 0/8). Similar patterns were observed with Briotech (cutting board: n= 3; replicates= 7/8, 1/8, 0/8; knife: n= 3; replicates = 0/8, 0/8, 0/8). We did not detect CWD prions on the knives or cutting boards after disinfecting with Virkon-S, 10% bleach, and 40% bleach.
Conclusions: These preliminary results suggest that Dawn dish soap and Briotech do not reliably decontaminate CWD prions from these surfaces. Our data suggest that Virkon-S and various bleach concentrations are more effective in reducing prion contamination of meat processing surfaces; however, surface type may also influence the ability of prions to adsorb to surfaces, preventing complete decontamination. Our results will directly inform best practices to prevent the introduction of CWD prions into the human food chain during venison processing.
Acknowledgement: Funding was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR), the Rapid Agriculture Response Fund (#95385/RR257), and the Michigan Department of Natural Resources.
Theme: Animal prion diseases
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Prion 2023 Abstracts
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
***> Price of TSE Prion Poker goes up substantially, all you cattle ranchers and such, better pay close attention here...terry <***
Transmission of the chronic wasting disease agent from elk to cattle after oronasal exposure
Justin Greenlee, Jifeng Bian, Zoe Lambert, Alexis Frese, and Eric Cassmann Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
Aims: The purpose of this study was to determine the susceptibility of cattle to chronic wasting disease agent from elk.
Materials and Methods: Initial studies were conducted in bovinized mice using inoculum derived from elk with various genotypes at codon 132 (MM, LM, LL). Based upon attack rates, inoculum (10% w/v brain homogenate) from an LM132 elk was selected for transmission studies in cattle. At approximately 2 weeks of age, one wild type steer (EE211) and one steer with the E211K polymorphism (EK211) were fed 1 mL of brain homogenate in a quart of milk replacer while another 1 mL was instilled intranasally. The cattle were examined daily for clinical signs for the duration of the experiment. One steer is still under observation at 71 months post-inoculation (mpi).
Results: Inoculum derived from MM132 elk resulted in similar attack rates and incubation periods in mice expressing wild type or K211 bovine PRNP, 35% at 531 days post inoculation (dpi) and 27% at 448 dpi, respectively. Inoculum from LM132 elk had a slightly higher attack rates in mice: 45% (693 dpi) in wild type cattle PRNP and 33% (468) in K211 mice. Inoculum from LL132 elk resulted in the highest attack rate in wild type bovinized mice (53% at 625 dpi), but no K211 mice were affected at >700 days. At approximately 70 mpi, the EK211 genotype steer developed clinical signs suggestive of prion disease, depression, low head carriage, hypersalivation, and ataxia, and was necropsied. Enzyme immunoassay (IDEXX) was positive in brainstem (OD=4.00, but non-detect in retropharyngeal lymph nodes and palatine tonsil. Immunoreactivity was largely limited to the brainstem, midbrain, and cervical spinal cord with a pattern that was primarily glia-associated.
Conclusions: Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material.
Funded by: This research was funded in its entirety by congressionally appropriated funds to the United States Department of Agriculture, Agricultural Research Service. The funders of the work did not influence study design, data collection and analysis, decision to publish, or preparation of the manuscript.
"Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material."
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Strain characterization of chronic wasting disease in bovine-PrP transgenic mice
Nuria Jerez-Garrido1, Sara Canoyra1, Natalia Fernández-Borges1, Alba Marín Moreno1, Sylvie L. Benestad2, Olivier Andreoletti3, Gordon Mitchell4, Aru Balachandran4, Juan María Torres1 and Juan Carlos Espinosa1. 1 Centro de Investigación en Sanidad Animal, CISA-INIA-CSIC, Madrid, Spain. 2 Norwegian Veterinary Institute, Ås, Norway. 3 UMR Institut National de la Recherche Agronomique (INRA)/École Nationale Vétérinaire de Toulouse (ENVT), Interactions Hôtes Agents Pathogènes, Toulouse, France. 4 Canadian Food Inspection Agency, Ottawa, Canada.
Aims: Chronic wasting disease (CWD) is an infectious prion disease that affects cervids. Various CWD prion strains have been identified in different cervid species from North America and Europe. The properties of the infectious prion strains are influenced by amino acid changes and polymorphisms in the PrP sequences of different cervid species. This study, aimed to assess the ability of a panel of CWD prion isolates from diverse cervid species from North America and Europe to infect bovine species, as well as to investigate the properties of the prion strains following the adaptation to the bovine-PrP context.
Materials and Methods: BoPrP-Tg110 mice overexpressing the bovine-PrP sequence were inoculated by intracranial route with a panel of CWD prion isolates from both North America (two white-tailed deer and two elk) and Europe (one reindeer, one moose and one red deer).
Results: Our results show distinct behaviours in the transmission of the CWD isolates to the BoPrP-Tg110 mouse model. Some of these isolates did not transmit even after the second passage. Those able to transmit displayed differences in terms of attack rate, survival times, biochemical properties of brain PrPres, and histopathology.
Conclusions: Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study.
Funded by: MCIN/AEI /10.13039/501100011033 and by European Union NextGeneration EU/PRTR
Grant number: PCI2020-120680-2 ICRAD
"Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study."
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https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
MONDAY, OCTOBER 16, 2023
Transmission of the chronic wasting disease agent from elk to cattle after oronasal exposure
Price of TSE Prion Poker goes up substantially, all you cattle ranchers and such, better pay close attention here...
https://chronic-wasting-disease.blogspot.com/2023/10/transmission-of-chronic-wasting-disease.html
PRION 2023 CONTINUED;
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
Detection of chronic wasting disease prions in processed meats
Rebeca Benavente1 , Francisca Bravo1,2, J. Hunter Reed3 , Mitch Lockwood3 , Glenn Telling4 , Rodrigo Morales1,2 1 Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; 2 Universidad Bernardo O’Higgins. Santiago, Chile; 3 Texas Parks and Wildlife Department, Texas, USA. 4 Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
Aims: identify the presence of CWD prions in processed meats derived from elk.
Materials and Methods: In this study, we analyzed different processed meats derived from a CWD-positive (pre-clinical) free-ranging elk. Products tested included filets, sausages, boneless steaks, burgers, seasoned chili meats, and spiced meats. The presence of CWD-prions in these samples were assessed by PMCA using deer and elk substrates. The same analyses were performed in grilled and boiled meats to evaluate the resistance of the infectious agent to these procedures.
Results: Our results show positive prion detection in all the samples analyzed using deer and elk substrates. Surprisingly, cooked meats displayed increased seeding activities. This data suggests that CWD-prions are available to people even after meats are processed and cooked.
Conclusions: These results suggest CWD prions are accessible to humans through meats, even after processing and cooking. Considering the fact that these samples were collected from already processed specimens, the availability of CWD prions to humans is probably underestimated.
Funded by: NIH and USDA
Grant number: 1R01AI132695 and APP-20115 to RM
Acknowledgement: We would like to thank TPWD personnel for providing us with valuable samples
"Our results show positive prion detection in all the samples analyzed using deer and elk substrates. Surprisingly, cooked meats displayed increased seeding activities."
end...
PRION 2023 CONTINUED;
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
Fortuitous generation of a zoonotic cervid prion strain
Manuel Camacho, Xu Qi, Liuting Qing, Sydney Smith, Jieji Hu, Wanyun Tao, Ignazio Cali, Qingzhong Kong. Department of Pathology, Case Western Reserve University, Cleveland, USA
Aims: Whether CWD prions can infect humans remains unclear despite the very substantial scale and long history of human exposure of CWD in many states or provinces of USA and Canada. Multiple in vitro conversion experiments and in vivo animal studies indicate that the CWD-to-human transmission barrier is not unbreakable. A major long-term public health concern on CWD zoonosis is the emergence of highly zoonotic CWD strains. We aim to address the question of whether highly zoonotic CWD strains are possible.
Materials and Methods: We inoculated several sCJD brain samples into cervidized transgenic mice (Tg12), which were intended as negative controls for bioassays of brain tissues from sCJD cases who had potentially been exposed to CWD. Some of the Tg12 mice became infected and their brain tissues were further examined by Western blot as well as serial passages in humanized or cervidized mice.
Results: Passage of sCJDMM1 in transgenic mice expressing elk PrP (Tg12) resulted in a “cervidized” CJD strain that we termed CJDElkPrP. We observed 100% transmission of the original CJDElkPrP in transgenic mice expressing human PrP. We passaged CJDElkPrP two more times in the Tg12 mice. We found that such second and third passage CJDElkPrP prions retained 100% transmission rate in the humanized mice, despite that the natural elk CWD isolates and CJDElkPrP share the same elk PrP sequence. In contrast, we and others found zero or poor transmission of natural elk CWD isolates in humanized mice.
Conclusions: Our data indicate that highly zoonotic cervid prion strains are not only possible but also can retain zoonotic potential after serial passages in cervids, suggesting a very significant and serious long-term risk of CWD zoonosis given that the broad and continuing spread of CWD prions will provide fertile grounds for the emergence of zoonotic CWD strains over time.
Funded by: NIH Grant number: R01NS052319, R01NS088604, R01NS109532
Acknowledgement: We want to thank the National Prion Disease Pathology Surveillance Center and Drs. Allen Jenny and Katherine O'Rourke for providing the sCJD samples and the CWD samples used in this study, respectively
"Our data indicate that highly zoonotic cervid prion strains are not only possible but also can retain zoonotic potential after serial passages in cervids, suggesting a very significant and serious long-term risk of CWD zoonosis given that the broad and continuing spread of CWD prions will provide fertile grounds for the emergence of zoonotic CWD strains over time."
PRION 2023 CONTINUED;
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
A probable diagnostic marker for CWD infection in humans
Xu Qi, Liuting Qing, Manuel Camacho, Ignazio Cali, Qingzhong Kong. Department of Pathology, Case Western Reserve University, Cleveland, USA
Aims: Multiple in vitro CWD-seeded human PrP conversion experiments and some animal model studies indicate that the species barrier for CWD to human transmission can be overcome, but whether CWD prion can infect humans in real life remains controversial. The very limited understanding on the likely features of CWD infection in humans and the lack of a reliable diagnostic marker for identification of acquired human CWD cases contribute to this uncertainty. We aim to stablish such a reliable diagnostic marker for CWD infections in humans should they occur.
Materials and Methods: A couple of PrPSc-positive spleens were identified from humanized transgenic mice inoculated with either CWD or sCJDMM1. Prions in these spleens were compared by bioassays in cervidized or humanized transgenic mice. A couple of PrPSc-positive spleens from UK sCJDMM1 patients were also examined similarly as controls with no exposure to CWD.
Results: We have detected two prion-positive spleens in humanized transgenic mice inoculated with some CWD isolates. Such experimentally generated splenic “humanized” CWD prions (termed eHuCWDsp) appear indistinguishable from prions in the brain of sCJDMM1 patients on Western blot. We compared eHuCWDsp with prions in the spleen from humanized mice infected with sCJDMM1 (termed sCJDMM1sp) by bioassays in cervidized or humanized transgenic mice. Significantly, we found that eHuCWDsp can efficiently infect not only the humanized mice but also cervidized transgenic mice, and cervidized mice infected by eHuCWDsp produced PrPSc and brain pathology that are practically identical to those of CWD-infected cervidized mice. In contrast, sCJDMM1sp, similar to prions from sCJDMM1 patient brains, is poorly transmissible in the cervidized mice.
Conclusions: Our data demonstrate that high transmissibility with CWD features of splenic prions in cervidized transgenic mice is unique to acquired human CWD prions, and it may serve as a reliable marker to identify the first acquired human CWD cases.
Funded by: NIH Grant number: R01NS052319, R01NS088604, R01NS109532
Acknowledgement: We want to thank the National Prion Disease Pathology Surveillance Center and Drs. Allen Jenny and Katherine O'Rourke for providing the sCJD samples and the CWD samples used in this study, respectively.
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PRION 2023 CONTINUED;
https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
THURSDAY, OCTOBER 19, 2023
CWD TSE PRION CERVID ENVIRONMENTAL RISK FACTORS 2023
https://chronic-wasting-disease.blogspot.com/2023/10/cwd-tse-prion-cervid-environmental-risk.html
PART 2. TPWD CHAPTER 65. DIVISION 1. CWD
31 TAC §§65.82, 65.85, 65.88
The Texas Parks and Wildlife Commission in a duly noticed meeting on May 25, 2023 adopted amendments to 31 TAC §§65.82, 65.85, and §65.88, concerning Disease Detection and Response, without changes to the proposed text as published in the April 21, 2023, issue of the Texas Register (48 TexReg 2048). The rules will not be republished.
Currently, there is scientific evidence to suggest that CWD has zoonotic potential; however, no confirmed cases of CWD have been found in humans.
17 DETECTION OF CHRONIC WASTING DISEASE PRIONS IN PROCESSED MEATS.
Rebeca Benavente1, Francisca Bravo1,2, Paulina Soto1,2, J. Hunter Reed3, Mitch Lockwood3, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile. 3Texas Parks and Wildlife, Austin, USA
Abstract
The zoonotic potential of chronic wasting disease (CWD) remains unknown. Currently, there are no known natural cases of CWD transmission to humans but increasing evidence suggests that the host range of CWD is not confined only to cervid species. Alarmingly, recent experimental evidence suggests that certain CWD isolates can induce disease in non-human primates. While the CDC strongly recommends determining CWD status in animals prior to consumption, this practice is voluntary. Consequently, it is plausible that a proportion of the cervid meat entering the human food chain may be contaminated with CWD. Of additional concern is that traditional diagnostic techniques used to detect CWD have relatively low sensitivity and are only approved for use in tissues other than those typically ingested by humans. In this study, we analyzed different processed meats derived from a pre-clinical, CWD-positive free-ranging elk. Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats. CWD-prion presence in these products were assessed by PMCA using deer and elk substrates. Our results show positive prion detection in all products. To confirm the resilience of CWD-prions to traditional cooking methods, we grilled and boiled the meat products and evaluated them for any remnant PMCA seeding activity. Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking. Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
***> Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats.
***> CWD-prion presence in these products were assessed by PMCA using deer and elk substrates.
***> Our results show positive prion detection in all products.
***> Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking.
***> Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
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9 Carrot plants as potential vectors for CWD transmission.
Paulina Soto1,2, Francisca Bravo-Risi1,2, Claudio Soto1, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile
***> We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts.
***> Our results indicate that edible plants could participate as vectors of CWD transmission.
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Transmission of prion infectivity from CWD-infected macaque tissues to rodent models demonstrates the zoonotic potential of chronic wasting disease.
Samia Hannaoui1,2, Ginny Cheng1,2, Wiebke Wemheuer3, Walter Schulz-Schaeffer3, Sabine Gilch1,2, Hermann Schatzl1,2 1University of Calgary, Calgary, Canada. 2Calgary Prion Research Unit, Calgary, Canada. 3Institute of Neuropathology, Medical Faculty, Saarland University, Homburg/Saar, Germany
***> Further passage to cervidized mice revealed transmission with a 100% attack rate.
***> Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one.
****> The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Epidemiologic surveillance of prion disease among cervid hunters and people likely to have consumed venison contaminated with chronic wasting disease
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https://intcwdsympo.files.wordpress.com/2023/06/final-agenda-with-abstracts.pdf?force_download=true
Transmission of Cervid Prions to Humanized Mice Demonstrates the Zoonotic Potential of CWD
Samia Hannaouia, Irina Zemlyankinaa, Sheng Chun Changa, Maria Immaculata Arifina, Vincent Béringueb, Debbie McKenziec, Hermann M. Schatzla, and Sabine Gilcha
Results: Here, we provide the strongest evidence supporting the zoonotic potential of CWD prions, and their possible phenotype in humans. Inoculation of mice expressing human PrPCwith deer CWD isolates (strains Wisc-1 and 116AG) resulted in atypical clinical manifestations in > 75% of the mice, with myoclonus as leading clinical sign. Most of tg650brain homogenates were positive for seeding activity in RT-QuIC. Clinical disease and presentation was transmissible to tg650 mice and bank voles. Intriguingly, protease-resistant PrP in the brain of tg650 mice resembled that found in a familial human prion disease and was transmissible upon passage. Abnormal PrP aggregates upon infection with Wisc-1 were detectable in thalamus, hypothalamus, and midbrain/pons regions.
Unprecedented in human prion disease, feces of CWD-inoculated tg650 mice harbored prion seeding activity and infectious prions, as shown by inoculation of bank voles and tg650 with fecal homogenates.
Conclusions: This is the first evidence that CWD can infect humans and cause disease with a distinctive clinical presentation, signature, and tropism, which might be transmissible between humans while current diagnostic assays might fail to detect it. These findings have major implications for public health and CWD-management.
https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2091286
The finding that infectious PrPSc was shed in fecal material of CWD-infected humanized mice and induced clinical disease, different tropism, and typical three banding pattern-PrPres in bank voles that is transmissible upon second passage is highly concerning for public health. The fact that this biochemical signature in bank voles resembles that of the Wisc-1 original deer isolate and is different from that of bvWisc-1, in the migration profile and the glyco-form-ratio, is valid evidence that these results are not a product of contamination in our study. If CWD in humans is found to be contagious and transmissible among humans, as it is in cervids [57], the spread of the disease within humans might become endemic.
Transmission of cervid prions to humanized mice demonstrates the zoonotic potential of CWD
Acta Neuropathol 144, 767–784 (2022). https://doi.org/10.1007/s00401-022-02482-9
Published
22 August 2022
https://link.springer.com/article/10.1007/s00401-022-02482-9
Transmission of cervid prions to humanized mice demonstrates the zoonotic potential of CWD
Samia Hannaoui1 · Irina Zemlyankina1 · Sheng Chun Chang1 · Maria Immaculata Arifn1 · Vincent Béringue2 · Debbie McKenzie3 · Hermann M. Schatzl1 · Sabine Gilch1
Received: 24 May 2022 / Revised: 5 August 2022 / Accepted: 7 August 2022
© The Author(s) 2022
Abstract
Prions cause infectious and fatal neurodegenerative diseases in mammals. Chronic wasting disease (CWD), a prion disease of cervids, spreads efficiently among wild and farmed animals. Potential transmission to humans of CWD is a growing concern due to its increasing prevalence. Here, we provide evidence for a zoonotic potential of CWD prions, and its probable signature using mice expressing human prion protein (PrP) as an infection model. Inoculation of these mice with deer CWD isolates resulted in atypical clinical manifestation with prion seeding activity and efficient transmissible infectivity in the brain and, remarkably, in feces, but without classical neuropathological or Western blot appearances of prion diseases. Intriguingly, the protease-resistant PrP in the brain resembled that found in a familial human prion disease and was transmissible upon second passage. Our results suggest that CWD might infect humans, although the transmission barrier is likely higher compared to zoonotic transmission of cattle prions. Notably, our data suggest a different clinical presentation, prion signature, and tissue tropism, which causes challenges for detection by current diagnostic assays. Furthermore, the presence of infectious prions in feces is concerning because if this occurs in humans, it is a source for human-to-human transmission. These findings have strong implications for public health and CWD management.
Keywords Chronic wasting disease · CWD · Zoonotic potential · Prion strains · Zoonotic prions
HIGHLIGHTS OF THIS STUDY
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Our results suggest that CWD might infect humans, although the transmission barrier is likely higher compared to zoonotic transmission of cattle prions. Notably, our data suggest a different clinical presentation, prion signature, and tissue tropism, which causes challenges for detection by current diagnostic assays. Furthermore, the presence of infectious prions in feces is concerning because if this occurs in humans, it is a source for human-to-human transmission. These findings have strong implications for public health and CWD management.
In this study, we evaluated the zoonotic potential of CWD using a transgenic mouse model overexpressing human M129-PrPC (tg650 [12]). We inoculated tg650 mice intracerebrally with two deer CWD isolates, Wisc-1 and 116AG [22, 23, 27, 29]. We demonstrate that this transgenic line was susceptible to infection with CWD prions and displayed a distinct leading clinical sign, an atypical PrPSc signature and unusual fecal shedding of infectious prions. Importantly, these prions generated by the human PrP transgenic mice were transmissible upon passage. Our results are the first evidence of a zoonotic risk of CWD when using one of the most common CWD strains, Wisc-1/CWD1 for infection. We demonstrated in a human transgenic mouse model that the species barrier for transmission of CWD to humans is not absolute. The fact that its signature was not typical raises the questions whether CWD would manifest in humans as a subclinical infection, whether it would arise through direct or indirect transmission including an intermediate host, or a silent to uncovered human-to-human transmission, and whether current detection techniques will be suffcient to unveil its presence.
Our findings strongly suggest that CWD should be regarded as an actual public health risk. Here, we use humanized mice to show that CWD prions can cross the species barrier to humans, and remarkably, infectious prions can be excreted in feces.
Our results indicate that if CWD crosses the species-barrier to humans, it is unlikely to resemble the most common forms of human prion diseases with respect to clinical signs, tissue tropism and PrPSc signature. For instance, PrPSc in variable protease-sensitive prionopathy (VPSPr), a sporadic form of human prion disease, and in the genetic form Gerstmann-Sträussler-Scheinker syndrome (GSS) is defined by an atypical PK-resistant PrPSc fragment that is non-glycosylated and truncated at both C- and N-termini, with a molecular weight between 6 and 8 kDa [24, 44–46]. These biochemical features are unique and distinctive from PrPSc (PrP27-30) found in most other human or animal prion disease. The atypical PrPSc signature detected in brain homogenate of tg650 mice #321 (1st passage) and #3063 (2nd passage), and the 7–8 kDa fragment (Figs. 2, 4) are very similar to that of GSS, both in terms of migration profile and the N-terminal cleavage site.
CWD in humans might remain subclinical but with PrPSc deposits in the brain with an unusual morphology that does not resemble the patterns usually seen in different prion diseases (e.g., mouse #328; Fig. 3), clinical with untraceable abnormal PrP (e.g., mouse #327) but still transmissible and uncovered upon subsequent passage (e.g., mouse #3063; Fig. 4), or prions have other reservoirs than the usual ones, hence the presence of infectivity in feces (e.g., mouse #327) suggesting a potential for human-to-human transmission and a real iatrogenic risk that might be unrecognizable.
suggesting a potential for human-to-human transmission and a real iatrogenic risk that might be unrecognizable.
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Supplementary Information The online version contains supplementary material available at
https://doi.org/10.1007/s00401-022-02482-9
snip...see full text;
https://link.springer.com/article/10.1007/s00401-022-02482-9
https://link.springer.com/content/pdf/10.1007/s00401-022-02482-9.pdf
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