TAHC CWD Summary Minutes of the 414th Commission Meeting November 15, 2022
TAHC CWD Summary Minutes of the 414th Commission Meeting November 15, 2022
Summary Minutes of the 414th Commission Meeting – 11/15/2022
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• Chronic Wasting Disease (CWD):
2021 Incident
310 total affected herds
o Seven positive facilities: three facilities in Uvalde, one in Duval, one in Hunt, one in Matagorda, & one in Mason
o 303 Trace herds:
177 Breeder facilities, 117 release sites, four nursing facilities, five DMP sites
o Status:
Released after meeting requirements:
- 164 breeder facilities, 58 release sites/DMPs/nursing facilities
Summary Minutes of the 414th Commission Meeting – 11/15/2022
3
Under a herd plan: three breeder facilities, 23 release sites/DMP
Pending a signed herd plan: three breeder facilities, 44 release sites/DMP
Out of state: eight facilities
2022 Incident
84 total affected herds
o 2 Positive facilities:
Gillespie County – Confirmed August 30th
Limestone County – Confirmed
o 82 Trace facilities: 22 breeder sites, 59 release sites, and one DMP site
o Status
Released after meeting requirements: seven breeder facilities, 2 release sites
Signed herd plan: nine release sites
Pending a signed herd plan: 15 Breeder facilities, 49 Release sites/DMP
USDA VS review of the Texas CWD HCP UPDATE
o TAHC is working with TPWD to modify the TWIMS database to better support the HCP
o Review of all enrolled herds has begun, and is to be completed by the end of February 2023
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Cooperative Award Award End Budget Rcd $$ Spent Encumbered Need to Spend
21 CWD Depop/Genome Study 9/14/2022 $429,598 $375,032 $375,032 $0 $56,566
21 CWD D4 TX (Depop) 9/14/2022 $274,968 $274,968 $274,968 $0 $0
22 CWD Lng Rnge/Low Energy 8/31/2023 $250,000 $0 $0 $0 $250,000
FY 2022-2023 Collected Fee Revenue:
$9,500 from CWD Inspection was projected, $16,550 was received year to date
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Item 13 – Consideration of and Possible Action on Proposed Rules Mr. Jabbar Fahim discussed the following Regulation Proposals:
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b) Chapter 40, Chronic Wasting Disease
The Texas Animal Health Commission (commission) proposes amendments to Title 4, Texas Administrative Code, Chapter 40, Chronic Wasting Disease. The proposed amendments both increase surveillance and reduce the risk of chronic wasting disease (CWD) being spread from areas where it may exist. §40.6 proposed adoption establishes one new containment zone (CZ) 5, expands existing CZ 2 and CZ 3, creates a new surveillance zone (SZ) 8, and modifies existing SZ 5 to either implement or improve surveillance efforts as part of the agency’s effort to manage chronic wasting disease (CWD).
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TEXAS CWD STRAIN
“Wow,” he said. “Unlike anything we've seen before.”
The prions from the Texas deer were a lot harder to destroy than the ones from the Colorado elk. In fact, the guanidine barely damaged them at all. “We’ve never seen that before in any prion strain, which means that it has a completely different structure than we've ever seen before,” says Zabel. And that suggests that it might be a very different kind of chronic wasting disease. The researchers ran the same test on another Texas deer, with the same results.
TEXAS CWD STRAIN
77. Assessing chronic wasting disease strain differences in free-ranging cervids across the United States
Kaitlyn M. Wagnera, Caitlin Ott-Connb, Kelly Strakab, Bob Dittmarc, Jasmine Battend, Robyn Piercea, Mercedes Hennessya, Elizabeth Gordona, Brett Israela, Jenn Ballarde and Mark D Zabela
aPrion Research Center at Colorado State University; bMichigan Department of Natural Resources; cTexas Parks and Wildlife Department; dMissouri Department of Conservation, 5. Arkansas Game and Fish Commission CONTACT Kaitlyn M. Wagner miedkait@rams.colostate.edu
ABSTRACT
Background/Introduction: Chronic wasting disease (CWD) is an invariably fatal prion disease affecting captive and free-ranging cervids, including white-tailed deer, mule deer, moose, elk, and reindeer. Since the initial description of the disease in the 1960’s, CWD has spread to 23 states, 3 Canadian Provinces, South Korea, Norway and, most recently, Finland. While some outbreaks of CWD were caused by transport of infected animals from endemic regions, the origin of CWD in other epizootics is unclear and has not been characterized. Previous studies have shown that there are two distinct strains of CWD. However, the continuous spread and the unclear origin of several outbreaks warrant continued surveillance and further characterization of strain diversity.
Materials and Methods: To address these knowledge gaps, we used biochemical tests to assess strain differences between CWD outbreaks in Michigan, Texas, Missouri, and Colorado, USA. Brain or lymph node samples were homogenized and digested in 50 µg/mL proteinase K (PK). These samples were then run on a Western blot to assess glycoform ratio and electrophoretic mobility. Texas samples were digested in 100 µg/mL PK. To assess conformational stability, brain or lymph node homogenates were incubated in increasing concentrations of guanidine hydrochloride from 0 M to 4 M in 0.5 M increments. Samples were then precipitated in methanol overnight, washed and PK digested in 50 µg/mL PK before slot blotting.
Results: Our results have found significant differences in glycoform ratio between CWD from Michigan and Colorado, but no differences were observed in conformational stability assays. Interestingly, when testing our CWD isolates from Texas to analyse electrophoretic mobility and glycoform ratio, we found that these samples did not exhibit the characteristic band shift when treated with PK, but PK resistant material remained. Additionally, results from our conformational stability assay demonstrate a unique profile of these Texas isolates. Testing of samples from Missouri is currently underway.
Conclusions: Thus far, our data indicate that there are strain differences between CWD circulating in Michigan and CWD in Colorado and provide important insight into CWD strain differences between two non-contiguous outbreaks. We have also identified a unique strain of CWD in Texas with biochemical strain properties not seen in any of our other CWD isolates. These results highlight the importance of continued surveillance to better understand this devastating disease. These results have important implications for CWD emergence, evolution and our understanding of prion strain heterogeneity on the landscape.
The disease devastating deer herds may also threaten human health
Scientists are exploring the origins of chronic wasting disease before it becomes truly catastrophic.
Rae Ellen Bichell
Image credit: David Parsons/Istock
April 8, 2019
This story was published in collaboration with the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUER in Salt Lake City and KRCC and KUNC in Colorado.
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One day in late February, in their laboratory in Fort Collins, Colorado, Wagner and Zabel compared the prions from the brains of CWD-infected deer in Texas with those of elk in Colorado. They want to know if the proteins were all mangled in the same way, or not. “If they are different, this would suggest that we have different strain properties, which is evidence as we're building our case that we might have multiple strains of CWD circulating in the U.S.,” says Wagner.
Step one is to see if they’re equally easy to destroy using a chemical called guanidine. The shape of a prion dictates everything, including the way it interacts with an animal’s cells and the ease with which chemicals can unfold it.
“Moment of truth,” said Wagner, as she and Zabel huddled around a computer, waiting for results to come through. When they did, Zabel was surprised.
“Wow,” he said. “Unlike anything we've seen before.”
The prions from the Texas deer were a lot harder to destroy than the ones from the Colorado elk. In fact, the guanidine barely damaged them at all. “We’ve never seen that before in any prion strain, which means that it has a completely different structure than we've ever seen before,” says Zabel. And that suggests that it might be a very different kind of chronic wasting disease. The researchers ran the same test on another Texas deer, with the same results.
Now, these are only the preliminary results from a few animals. Wagner and Zabel have a lot more experiments to do. But if future tests come to the same conclusion, it would support their hypothesis that there are multiple strains of chronic wasting disease out there, all with different origins. That, in turn, could mean that this disease will become even trickier to manage than it already is.
And, Zabel adds, there’s something else. “If it's still evolving, it may still evolve into a form that could potentially, eventually affect humans,” he says.
Zabel is not the only one worried about that possibility.
OSTERHOLM, THE EPIDEMIOLOGIST from Minnesota, is also concerned. He directs the Center for Infectious Disease Research and Policy at the University of Minnesota, and is serving a one-year stint as a “Science Envoy for Health Security” with the U.S. State Department. In February, he told Minnesota lawmakers that when it comes to chronic wasting disease, we are playing with fire. “You are going to hear from people that this is not going to be a problem other than a game farm issue. You're going to hear from people that it's not going to transmit to people, and I hope they're right, but I wouldn't bet on it,” he said. “And if we lose this one and haven’t done all we can do, we will pay a price.”
If that wasn’t warning enough, he added: “Just remember what happened in England.”
He was talking about mad cow disease. Decades ago, Osterholm got involved in studying the potential for the newly emerging condition — bovine spongiform encephalopathy, or BSE for short — to be transmitted to humans.
At that point, researchers had yet to document a prion disease in animals that could infect people. They did, however, have a few pieces of the puzzle. For one, work in Papua New Guinea had shown that people could transmit prion diseases to each other if they practiced cannibalism, especially of the brain-eating variety. They also knew that BSE was spreading quickly between cattle. Osterholm says he and others worried that the more widespread it became, the more chances it might have to change into something that could sicken people.
“A lot of people thought that it was an overreaction,” says Osterholm. “Then, of course, in 1996, 10 years later, we recognized that in fact transmission had occurred.” Variant Creutzfeldt-Jakob disease, as the illness is called when it appears in human beings, has infected about 230 people worldwide. Osterholm says he feels like he’s having déjà vu, except that instead of mad cow, now it’s chronic wasting disease that’s spreading in animals, with the potential to cross the species barrier to infect humans.
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***> 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.''
Biologists Stress Testing Harvests for Chronic Wasting Disease During Deer Season
Dec. 2, 2022
Media Contact: TPWD News, Business Hours, 512-389-8030
TEXAS CWD 429 CASES CONFIRMED TO DATE
Texas Chronic Wasting Disease CWD TSE Prion Increases To 428 Confirmed To Date
Biologists Stress Testing Harvests for Chronic Wasting Disease During Deer Season
DEC. 2, 2022
MEDIA CONTACT: TPWD NEWS, BUSINESS HOURS, 512-389-8030
News Image Share on Facebook Share Release URL
AUSTIN— With the recent discovery of Chronic Wasting Disease (CWD) in Kaufman County, Texas Parks and Wildlife Department (TPWD) biologists are stressing the importance of testing harvested deer taken this hunting season to curb the spread of this deadly disease.
CWD is a highly contagious and fatal neurological disease affecting members of the deer family such as white-tailed deer, mule deer, elk and moose. Hunters and landowners can voluntarily submit their harvest for free CWD testing at a TPWD check station or by contacting local wildlife biologists.
First recognized in 1967 in captive mule deer in Colorado, CWD has since been documented in captive and/or free-ranging deer in 30 states and three Canadian provinces. To date, 428 captive or free-ranging cervids — including white-tailed deer, mule deer, red deer, and elk — in 17 Texas counties have tested positive for CWD.
Eradication of CWD is very difficult if not impossible when established in free-ranging deer populations and in the environment. Testing for CWD allows wildlife biologists and animal health officials to get a clearer picture of the prevalence and distribution of the disease across Texas. Proactive monitoring improves the state’s response time to a CWD detection and can greatly reduce the risk of the disease further spreading to neighboring captive and free-ranging populations.
Those hunting in CWD surveillance and containment zones need to know the submission requirements
for susceptible species before hitting the field this season. Anyone hunting in an established CWD zone must bring their deer to a check station within 48 hours of harvest for testing.
There are about 30 check stations and drop boxes across the state in Kimble County, far West Texas, South Central Texas, the northwest Panhandle, Val Verde County, Hunt County, Lubbock County, Gillespie County, Limestone County and Duval County.
For more information about CWD, visit the TPWD website, the Texas Animal Health Commission website, or read about how hunters can help protect deer from CWD with a story from the Texas Parks and Wildlife Magazine.
Find TPWD veterinarians speaking about CWD on the TPWD YouTube page.
Texas CWD Confirmed High Fence Release Site Kaufman County, To Date 420 Cases Confirmed
Chronic Wasting Disease Detected at a High Fence Release Site in Kaufman County
Nov. 28, 2022 Media Contact: TPWD News, Business Hours, 512-389-8030
AUSTIN –Chronic Wasting Disease (CWD) was detected on a high fence release site in Kaufman County. This is the first positive detection of CWD in the county.
The white-tailed buck, harvested at a high-fence release site located in a CWD Surveillance Zone, was delivered to a Hunt County CWD check station in compliance with surveillance zone requirements. Texas Parks and Wildlife Department (TPWD) and Texas Animal Health Commission (TAHC) received notice of the CWD-positive test result from the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) on Nov. 14.
Prior to this detection, the high-fence release site was identified as a “trace herd” property to the Hunt County CWD-positive deer breeding facility reported on March 31, 2021, meaning deer were transferred from the Hunt County facility to this release site prior to discovery of CWD in that facility. Plans to conduct additional CWD investigations are underway.
“The incubation period of CWD can span years, creating disease detection and management challenges as seen in this recent detection,” said Andy Schwartz, TAHC Executive Director and State Veterinarian.
Animal health and wildlife officials will continue investigations to determine the extent of the disease within the property and mitigate risks to Texas’ CWD-susceptible species. Adequate surveillance and quick detection of CWD can help mitigate the disease’s spread.
“The discovery of CWD on this ranch is an unfortunate situation that TPWD and TAHC take very seriously,” said John Silovsky, TPWD Wildlife Division Director. “Both agencies will respond appropriately to this matter to protect the state’s susceptible species from further disease exposure. Hunters are reminded of the requirement to bring their harvested deer to the check station within 48 hours of harvest.”
First recognized in 1967 in captive mule deer in Colorado, CWD has since been documented in captive and/or free-ranging deer in 30 states and three Canadian provinces. To date, 420 captive or free-ranging cervids — including white-tailed deer, mule deer, red deer, and elk — in 17 Texas counties have tested positive for CWD. For more information on previous detections visit the CWD page on the TPWD website.
Testing for CWD allows wildlife biologists and animal health officials to get a clearer picture of the prevalence and distribution of the disease across Texas. Proactive monitoring improves the state’s response time to a CWD detection and can greatly reduce the risk of the disease further spreading to neighboring captive and free-ranging populations.
This confirmation is a good reminder to those hunting in CWD surveillance and containment zones to know the submission requirements for CWD susceptible species. Additionally, hunters outside of established surveillance and containment zones are encouraged to voluntarily submit their harvest for testing at a check station, for free, before heading home from the field. A map of TPWD check stations for all CWD zones can be found on the TPWD website.
For more information about CWD, visit the TPWD web site or the TAHC web site.
Counties where CWD Exposed Deer were Released
Number of CWD Exposed Deer Released by County
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).
PRION CONFERENCE 2022 ABSTRACTS CWD TSE PrP ZOONOSIS and ENVIRONMENTAL FACTORS
Chronic wasting disease detection in environmental and biological samples from a taxidermy site
Paulina Sotoa,b, J. Hunter Reedc, Mitch Lockwoodc, and Rodrigo Moralesa,b aDepartment of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; bUniversidad Bernardo O’Higgins, Santiago, Chile; cTexas Parks and Wildlife Department, Texas, USA
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy affecting captive and free-ranging cervids (e.g., mule deer, white-tailed deer, elk, reindeer, and moose). Nowadays, CWD is widely distributed in North America. It is suggested that CWD spreads due to direct animal contact or through exposure to contaminated environments previously inhabited by infected animals. CWD may also be spread through the movement of infected animals and carcasses. Taxidermy practices involve processing deer tissues (or whole animal carcasses). In many cases, the CWD status of processed animals is unknown. This can generate risks of disease spread and transmission. Taxidermy practices include different steps involving physical, chemical, and biological procedures. Without proper tissue handling or disposal practices, taxidermist facilities may become a focus of prion infectivity.
Aims: In this study, we evaluated the presence of infectious prions in a taxidermy facility believed to be exposed to CWD. Detection was performed using the Protein Misfolding Cyclic Amplification (PMCA) technique in biological and inert environmental samples.
Methods: We collected biological and environmental samples (plants, soils, insects, excreta, and others) from a taxidermy facility, and we tested these samples using the PMCA technique. In addition, we swabbed different surfaces possibly exposed to CWD-infected animals. For the PMCA reaction, we directly used a swab piece or 10 µL of 20% w/v homogenized samples.
Results: The PMCA analysis demonstrated CWD seeding activity in some of the components of this facility, including insects involved in head processing, soils, and a trash dumpster.
Conclusions: Different areas of this property were used for various taxidermy procedures. We were able to detect the presence of prions in
i) soils that were in contact with the heads of dead animals,
ii) insects involved in the cleaning of skulls, and
iii) an empty dumpster where animal carcasses were previously placed.
This is the first report demonstrating that swabbing is a helpful method to screen for prion infectivity on surfaces potentially contaminated with CWD. These findings are relevant as this swabbing and amplification strategy may be used to evaluate the disease status of other free-ranging and captive settings where there is a concern for CWD transmissions, such as at feeders and water troughs with CWD-exposed properties. This approach could have substantial implications for free-ranging cervid surveillance as well as in epidemiological investigations of CWD.
Carrot plants as potential vectors for CWD transmission
Paulina Sotoa,b, Francisca Bravo-Risia,b, Claudio Sotoa, and Rodrigo Moralesa,b
aDepartment of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; bUniversidad Bernardo O’Higgins, Santiago, Chile
Prion diseases are infectious neurodegenerative disorders afflicting humans and other mammals. These diseases are generated by the misfolding of the cellular prion protein into a disease-causing isoform. Chronic wasting disease (CWD) is a prevalent prion disease affecting cervids (captive and free-range). CWD is thought to be transmitted through direct animal contact or by indirect exposure to contaminated environments. Many studies have shown that infectious prions can enter the environment through saliva, feces, or urine from infected animals and decaying carcasses. However, we do not fully understand the specific contribution of each component to disease transmission events. Plants are logical environmental components to be evaluated since they grow in environments contaminated with CWD prions and are relevant for animal and human nutrition.
Aims: The main objective of this study is to study whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait.
Methods: We have grown carrot plants in CWD-infected soils. After 90 days, we harvested the carrots and separated them from the leaves. The experiment was controlled by growing plants in soil samples treated with brain extracts from healthy animals. These materials were interrogated for their prion seeding activity using the Protein Misfolding Cyclic Amplification (PMCA) technique. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The animals were sacrificed when they showed established signs of prion disease. Animals not displaying clinical signs were sacrificed at 600 days post-inoculation.
Results: The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions, as well as in carrot plants (leaves and roots) grown on them. Bioassays demonstrated that both leaves and roots contained CWD prions in sufficient quantities to induce disease (92% attack rate). As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. Animals treated with soil and plant components exposed with CWD-free brain extracts did not display prion-associated clinical signs or evidence of sub-clinical prion infection.
Conclusions: We show that edible plant components can absorb prions from CWD contaminated soils and transport them to their aerial parts. Our results indicate that plants could participate as vectors of CWD transmission. Importantly, plants designated for human consumption represent a risk of introducing CWD prions into the human food chain.
Large-scale PMCA screening of retropharyngeal lymph nodes and in white-tailed deer and comparisons with ELISA and IHC: the Texas CWD study
Rebeca Benaventea, Paulina Sotoa, Mitch Lockwoodb, and Rodrigo Moralesa
aDepartment of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA; bTexas Park and Wildlife Department, Texas, USA
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy that affects various species of cervids, and both free-ranging and captive animals. Until now, CWD has been detected in 3 continents: North America, Europe, and Asia. CWD prevalence in some states may reach 30% of total animals. In Texas, the first case of CWD was reported in a free-range mule deer in Hudspeth and now it has been detected in additional 14 counties. Currently, the gold standard techniques used for CWD screening and detection are ELISA and immunohistochemistry (IHC) of obex and retropharyngeal lymph nodes (RPLN). Unfortunately, these methods are known for having a low diagnostic sensitivity. Hence, many CWD-infected animals at pre-symptomatic stages may be misdiagnosed. Two promising in vitro prion amplification techniques, including the real-time quaking-induced conversion (RT-QuIC) and the protein misfolding cyclic amplification (PMCA) have been used to diagnose CWD and other prion diseases in several tissues and bodily fluids. Considering the low cost and speed of RT-QuIC, two recent studies have communicated the potential of this technique to diagnose CWD prions in RPLN samples. Unfortunately, the data presented in these articles suggest that identification of CWD positive samples is comparable to the currently used ELISA and IHC protocols. Similar studies using the PMCA technique have not been reported.
Aims: Compare the CWD diagnostic potential of PMCA with ELISA and IHC in RPLN samples from captive and free-range white-tailed deer. Material and Methods: In this study we analyzed 1,003 RPLN from both free-ranging and captive white-tailed deer collected in Texas. Samples were interrogated with the PMCA technique for their content of CWD prions. PMCA data was compared with the results obtained through currently approved techniques.
Results: Our results show a 15-fold increase in CWD detection in free-range deer compared with ELISA. Our results unveil the presence of prion infected animals in Texas counties with no previous history of CWD. In the case of captive deer, we detected a 16% more CWD positive animals when compared with IHC. Interestingly, some of these positive samples displayed differences in their electroforetic mobilities, suggesting the presence of different prion strains within the State of Texas.
Conclusions: PMCA sensitivity is significantly higher than the current gold standards techniques IHC and ELISA and would be a good tool for rapid CWD screening.
PRION CONFERENCE 2022 ABSTRACTS CWD TSE PrP ZOONOSIS
Transmission of prion infectivity from CWD-infected macaque tissues to rodent models demonstrates the zoonotic potential of chronic wasting disease.
Samia Hannaouia, Ginny Chenga, Wiebke Wemheuerb, Walter J. Schulz-Schaefferb, Sabine Gilcha, and Hermann M. Schätzla
Aims: Chronic wasting disease (CWD) is a prion disease of cervids. Its rapid geographic expansion, shedding of infectivity and persistence in the environment for many years are of concern for humans. Here, we provide the first evidence by transmission experiments to different transgenic mouse models and bank voles that Cynomolgus macaques inoculated via different routes with CWD-positive cervid tissues harbor infectious prions that elicit clinical disease in rodents.
Material and Methods: We used tissue materials from macaques inoculated with CWD to inoculate transgenic mice overexpressing cervid PrPCfollowed by transmission into bank voles. We used RT-QuIC, immunoblot and PET blot analysis to assess brains, spinal cords, and tissues of the gastrointestinal tract (GIT) for the presence of prions.
Results: Our results show that of the macaque materials that induced clinical disease in transgenic mice,73% were from the CNS (46% spinal cord and 27% brain), and 27% were from the spleen, although attack rates were low around 20%. Clinical mice did not display PK-resistant PrPSc(PrPres) in immunoblot, but showed low-levels of prion seeding activity. Transmission into bank voles from clinical transgenic mice led to a 100% attack rate with typical PrPressignature in immunoblot, which was different from that of voles inoculated directly with CWD or scrapie prions. High-level prion seeding activity in brain and spinal cord and PrPresdeposition in the brain were present. Remarkably, we also found prion seeding activity in GIT tissues of inoculated voles. Second passage in bank voles led to a 100% attack rate in voles inoculated with brain, spinal cord and small intestine material from first round animals, with PrPresin immunoblot, prion seeding activity, and PrPresdeposition in the brain. Shortened survival times indicate adaptation in the new host. This also shows that prions detected in GIT tissues are infectious and transmissible. Transmission of brain material from sick voles back to cervidized mice revealed transmission in these mice with a 100% attack rate, and interestingly, with different biochemical signature and distribution in the brain.
Conclusions: Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including oral one. The disease manifested as atypical in macaques and transgenic mice, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
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
Aims: 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 aimed to determine the zoonotic potential of CWD using a mouse model for human prion diseases.
Material and Methods: Transgenic mice overexpressing human PrPChomozygous for methionine at codon 129 (tg650) were inoculated intracerebrally with brain homogenates of white-tailed deer infected with Wisc-1/CWD1 or 116AG CWD strains. Mice were monitored for clinical signs and were euthanized at terminal disease. Brains were tested by RT-QuIC, western blot upon PK digestion, and immunohistochemistry; fecal homogenates were analyzed by RT-QuIC. Brain/spinal cord and fecal homogenates of CWD-inoculated tg650 mice were inoculated into tg650 mice or bank voles. Brain homogenates of bank voles inoculated with fecal homogenates of CWD-infected tg650 mice were used for second passage in bank voles.
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 tg650 brain 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.
DEFRA What is the risk of chronic wasting disease being introduced into Great Britain? A Qualitative Risk Assessment October 2012
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 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.
***>This is very likely to have parallels with control efforts for CWD in cervids.
***> Infectious agent of sheep scrapie may persist in the environment for at least 16 years
***> Nine of these recurrences occurred 14–21 years after culling, apparently as the result of environmental contamination, but outside entry could not always be absolutely excluded.
JOURNAL OF GENERAL VIROLOGY Volume 87, Issue 12
Infectious agent of sheep scrapie may persist in the environment for at least 16 years Free
Gudmundur Georgsson1, Sigurdur Sigurdarson2, Paul Brown3
Front. Vet. Sci., 14 September 2015 | https://doi.org/10.3389/fvets.2015.00032
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
imageTimm Konold1*, imageStephen A. C. Hawkins2, imageLisa C. Thurston3, imageBen C. Maddison4, imageKevin C. Gough5, imageAnthony Duarte1 and imageHugh A. Simmons1
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
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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.
Control of Chronic Wasting Disease OMB Control Number: 0579-0189 APHIS-2021-0004 Singeltary Submission
Docket No. APHIS-2018-0011 Chronic Wasting Disease Herd Certification
APHIS Indemnity Regulations [Docket No. APHIS-2021-0010] RIN 0579-AE65 Singeltary Comment SubmissionComment from Singeltary Sr., TerryPosted by the Animal and Plant Health Inspection Service on Sep 8, 2022
Comment from Terry Singeltary Sr.
Posted by the Food and Drug Administration on May 17, 2016
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
Greetings again FDA and Mr. Pritchett et al,
MY comments and source reference of sound science on this very important issue are as follows ;
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
I kindly wish to once again submit to Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed.
Thank you kindly for allowing me to comment again, ...and again...and again, on a topic so important, why it is 'NON-BINDING' is beyond me.
this should have been finalized and made 'BINDING' or MANDATORY OVER A DECADE AGO.
but here lay the problem, once made 'BINDING' or 'MANDATORY', it is still nothing but ink on paper.
we have had a mad cow feed ban in place since August 1997, and since then, literally 100s of millions of pounds BANNED MAD COW FEED has been sent out to commerce and fed out (see reference materials).
ENFORCEMENT OF SAID BINDING REGULATIONS HAS FAILED US TOO MANY TIMES.
so, in my opinion, any non-binding or voluntary regulations will not work, and to state further, 'BINDING' or MANDATORY regulations will not work unless enforced.
with that said, we know that Chronic Wasting Disease CWD TSE Prion easily transmits to other cervid through the oral route.
the old transmission studies of BSE TSE floored scientist once they figured out what they had, and please don't forget about those mink that were fed 95%+ dead stock downer cow, that all came down with TME. please see ;
It is clear that the designing scientists must also have shared Mr Bradleys surprise at the results because all the dose levels right down to 1 gram triggered infection.
it is clear that the designing scientists must have also shared Mr Bradleys surprise at the results because all the dose levels right down to 1 gram triggered infection.
Evidence That Transmissible Mink Encephalopathy Results from Feeding Infected Cattle
Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.
snip...
The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...
To further complicate things, we now know that science has shown that plants and vegetables can uptake the TSE Prion, and that the Scrapie agent can still be infectious from soil 16 years later. a frightening thought with the CWD running rampant now in North America (please see source reference materials below).
IF we don't do this, we have failed, and the TSE Prion agent will continue to spread, as it is doing as we speak.
I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids, as well as non-ruminants such as cats and dogs as well, as soon as possible for the following reasons...
31 Jan 2015 at 20:14 GMT
*** Ruminant feed ban for cervids in the United States? ***
31 Jan 2015 at 20:14 GMT
see Singeltary comment ;
Notice of Request To Renew an Approved Information Collection: Specified Risk Materials DOCKET NUMBER Docket No. FSIS-2022-0027 Singeltary Submission
Singeltary further comments in attachment;
Specified Risk Materials DOCKET NUMBER Docket No. FSIS-2022-0027 Singeltary Submission Attachment
https://downloads.regulations.gov/FSIS-2022-0027-0002/attachment_1.pdf
please see further ;
REFERENCE MATERIALS
snip...
Terry S. Singeltary Sr.
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
2003D-0186 Guidance for Industry: Use of Material From Deer and Elk In Animal Feed
EMC 1 Terry S. Singeltary Sr. Vol #: 1
PLEASE SOURCE REFERENCES UPLOADED FILES AT BOTTOM, SEE ATTACHMENT...
SEE SINGELTARY ATTACHMENT;
see Texas CWD History;
Terry S. Singeltary Sr. Bacliff, Texas USA 77518 flounder9@verizon.net
posted by Terry S. Singeltary Sr. at
12:47 PM
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