Chronic Wasting Disease: Texas CWD Confirmed High Fence Release Site Kaufman County, To Date 420 Cases Confirmed

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.

https://tpwd.texas.gov/newsmedia/releases/?req=20221128a

''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.''

TAHC OFFICIAL MINUTES OF THE 413th COMMISSION MEETING TSE PRION July 26, 2022

OFFICIAL MINUTES OF THE 413th COMMISSION MEETING Texas Animal Health Commission July 26, 2022

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• Chronic Wasting Disease (CWD):

 Positive WTD Breeder Facilities: seven in 2021

o Four have been depopulated

o One breeder depopulated his breeder deer on his own in mid-April.

o One signed a Genetic Herd Plan

o One is in litigation

 Trace Herds: 303 WTD facilities with connections to a positive facility

o 221 facilities released after meeting requirements (164 Breeder & 57 Release sites/DMP)

o 24 facilities are under a Herd Plan (2 Breeder & 22 Release Sites/DMP)

o 50 facilities are pending a signed Herd Plan (4 Breeder & 46 Release Sites/DMP)

o Eight out of State

 USDA VS review of the Texas CWD HCP UPDATE

o Adoption of proposed changes to Chapter 40, Chronic Wasting Disease, up for consideration today

o TAHC staff have worked diligently to develop and obtain USDA approval of consistent procedures to address noncompliance with federal and state HCP requirements.

o The TAHC CWD Field Manual has been updated, along with pertinent forms and agreements

o TAHC personnel participated in HCP Training and Q&A sessions hosted by USDA

o TAHC is working with TPWD to modify the TWIMS database to better support the HCP

o HCP participants have been notified in writing of changes in requirements

o Review of all enrolled herds has begun, and is to be completed in the next six months

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21 CWD D4 TX (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

 $9,500 from CWD Inspection was projected, $13,500 was received year to date

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Item 14 – Consideration of and Possible Action on Adoption of Proposed Rules

Ms. Mary Luedeker discussed the following Regulation Proposals:

Each Regulation Proposal was reviewed and voted on individually.

a) Chapter 40, Chronic Wasting Disease

b) Chapter 51, Entry Requirements

a) The Texas Animal Health Commission proposes ADOPTION of amendments Title 4, Texas Administrative Code, Chapter 40 titled “Chronic Wasting Disease”. Specifically, proposed changes clarify, correct, and update information regarding CWD Herd Certification Program and disease management as well as aligning with revised USDA CWD Program Standards and applicable federal regulations. Changes to portions of §40.1 proposal define CWD-Exposed Herd and CWD-Positive Animals. §40.3 proposals include requiring immediate reporting upon discovery all farmed or captive cervids that escape or disappear and all free-ranging cervids that enter the facility and removes exception for lowering a herd status to First Year for herds that acquire animals from nonparticipating herds and that animal is “not detected” postmortem within the first year after entry into the herd. Finally, it requires all identification to be visually verified on 100% of the animals during a physical herd inspection.

The motion ADOPT amendments to Chapter 40, Chronic Wasting Disease, was made by Commissioner Vermedahl, and seconded by Commissioner Jordan. The motion carried.

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https://www.tahc.texas.gov/agency/meetings/minutes/Minutes_CommMtg_2022-07-26.pdf

TEXAS CWD TSE PRION 409 CASES CONFIRMED TO DATE TPWD EMERGENCY RULE ADDS TWO NEW SURVEILLANCE ZONES LOCATED PRIMARILY IN GILLESPIE AND LIMESTONE COUNTIES.

TPWD Establishes Two New Surveillance Zones to Test for Chronic Wasting Disease

NOV. 4, 2022 Media Contact: TPWD News, Business Hours, 512-389-8030 News

AUSTIN –Texas Parks and Wildlife Commission has directed Texas Parks and Wildlife Department (TPWD) Executive Director Carter Smith to establish by emergency rule two new chronic wasting disease (CWD) surveillance zones located primarily in Gillespie and Limestone counties. The two new surveillance zones will go into effect prior to the start of the general hunting season beginning Nov. 5.

TPWD developed the zones following the detection of CWD earlier this year in a deer breeding facility located in Gillespie County and a deer breeding facility located in Limestone County.

Surveillance zones cover areas where the presence of CWD could reasonably be expected and enhance efforts to monitor and contain disease spread. Surveillance zone rules require hunters who harvest mule deer or white-tailed deer within the zone to bring their animals to a TPWD check station within 48 hours of harvest. Hunters must check each animal harvested and receive a CWD receipt before taking any part of that animal, including meat or quartered parts, from the zone.

“Testing for CWD allows wildlife biologists and animal health officials to get a clearer picture of the prevalence and distribution of the disease in those areas,” said TPWD Wildlife Division Director John Silovsky. “Proactive monitoring improves the state’s response time to a CWD detection and can greatly reduce the risk of the disease spreading further to neighboring captive and free-ranging populations.”

The surveillance zone located primarily in northwest Gillespie County encompasses 117,282 acres and includes parts of Kimble and Mason counties.

TPWD will establish two check stations – one in the city park in Harper, and the other on the grounds of the community center in Doss – along with self-serve drop boxes.

The surveillance zone located primarily in northern Limestone County encompasses 118,687 acres and includes parts of two other counties – Navarro and Hill – allowing access to a processor in Hubbard and a check station in Coolidge.

Hunters can find maps of these and other zones, along with locations and hours of check stations and self-serve drop boxes, on the TPWD website.

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 four Canadian provinces. To date, 409 captive or free-ranging cervids — including white-tailed deer, mule deer, red deer and elk — in 16 Texas counties have tested positive for CWD.

CWD is a fatal neurological disease affecting certain susceptible cervid species including white-tailed deer, mule deer, red deer, and elk. The disease is highly transmissible and can remain infectious on the landscape for several years. If left unmanaged, CWD can have long-term impacts on the native deer herd and local economies. Clinical signs may include progressive weight loss; incoordination; excessive thirst, salivation, or urination; loss of appetite; teeth grinding; abnormal head posture; and/or drooping ears. These signs may not become evident until years after animals first become infected. Therefore, testing remains the best available tool for detecting CWD at an early stage and containing it with appropriate management strategies.

TPWD encourages hunters outside established surveillance and containment zones to voluntarily submit their harvest for testing at a check station, for free, before heading home from the field. Hunters who harvest a CWD-susceptible species outside a CWD zone and wish to have the animal tested should contact their local TPWD wildlife biologist. If someone is interested in becoming a certified CWD sample collector, they should contact their local TPWD wildlife biologist or regional Texas Animal Health Commission (TAHC) Region Office.

To date, the risk of CWD transmitting to humans appears to be low; however, as a precaution, public health authorities recommend not consuming meat from infected animals.

For more information about CWD, visit the TPWD web site or the TAHC web site.

https://tpwd.texas.gov/newsmedia/releases/?req=20221104b

SATURDAY, SEPTEMBER 24, 2022

Texas Chronic Wasting Disease Confirmed at a Limestone County Deer Breeding Facility

To date, 392 captive or free-ranging cervids, including white-tailed deer, mule deer, red deer and elk, in 16 Texas counties have tested positive for CWD.

https://www.tahc.texas.gov/news/2022/2022-09-23_CWD_LimestoneCo.pdf

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

“Regarding the current situation involving CWD in permitted deer breeding facilities, TPWD records indicate that within the last five years, the seven CWD-positive facilities transferred a total of 2,530 deer to 270 locations in 102 counties and eight locations in Mexico (the destinations included 139 deer breeding facilities, 118 release sites, five Deer Management Permit sites, and three nursing facilities).'' ...

It is apparent that prior to the recent emergency rules, the CWD detection rules were ineffective at detecting CWD earlier in the deer breeding facilities where it was eventually discovered and had been present for some time; this creates additional concern regarding adequate mitigation of the risk of transferring CWD-positive breeder deer to release sites where released breeder deer come into contact with free-ranging deer...

Commission Agenda Item No. 5 Exhibit B

DISEASE DETECTION AND RESPONSE RULES

PROPOSAL PREAMBLE

1. Introduction.

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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

Texas CWD TSE Prion 409 Cases Confirmed To Date TPWD emergency rule adds two new surveillance zones located primarily in Gillespie and Limestone counties.

TPWD Establishes Two New Surveillance Zones to Test for Chronic Wasting Disease

Nov. 4, 2022

Media Contact: TPWD News, Business Hours, 512-389-8030

TPWD developed the zones following the detection of CWD earlier this year in a deer breeding facility located in Gillespie County and a deer breeding facility located in Limestone County.

The surveillance zone located primarily in northwest Gillespie County encompasses 117,282 acres and includes parts of Kimble and Mason counties. TPWD will establish two check stations – one in the city park in Harper, and the other on the grounds of the community center in Doss – along with self-serve drop boxes.

Hunters can find maps of these and other zones, along with locations and hours of check stations and self-serve drop boxes, on the TPWD website. 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 four Canadian provinces. To date, 409 captive or free-ranging cervids — including white-tailed deer, mule deer, red deer and elk — in 16 Texas counties have tested positive for CWD.

To date, the risk of CWD transmitting to humans appears to be low; however, as a precaution, public health authorities recommend not consuming meat from infected animals.

For more information about CWD, visit the TPWD web site or the TAHC web site.

https://tpwd.texas.gov/newsmedia/releases/?req=20221104b

SATURDAY, SEPTEMBER 24, 2022

Texas Chronic Wasting Disease Confirmed at a Limestone County Deer Breeding Facility

To date, 392 captive or free-ranging cervids, including white-tailed deer, mule deer, red deer and elk, in 16 Texas counties have tested positive for CWD.

https://www.tahc.texas.gov/news/2022/2022-09-23_CWD_LimestoneCo.pdf

see full listing of CWD positives at; (has not been updated)

https://tpwd.texas.gov/huntwild/wild/diseases/cwd/tracking/

Texas Chronic Wasting Disease Discovered at a Deer Breeding Facility in Gillespie County

Media Contacts: TAHC Communications public_info@tahc.texas.gov, 512.719.0750 TPWD Press Office news@tpwd.texas.gov, 512.389.8030

For Immediate Release

September 2, 2022

Chronic Wasting Disease Discovered at a Deer Breeding Facility in Gillespie County

AUSTIN, TX – Chronic Wasting Disease (CWD) has been discovered in a deer breeding facility in Gillespie County. The Texas Parks and Wildlife Department (TPWD) and Texas Animal Health Commission (TAHC) are collaboratively working to determine the source and extent of the first positive detection of the disease in this county.

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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, 376 captive or free-ranging cervids — including white-tailed deer, mule deer, red deer and elk — in 15 Texas counties have tested positive for CWD. For more information on previous detections visit the CWD page on the TPWD website.

https://www.tahc.texas.gov/news/2022/2022-09-02_CWD-GillespieCo.pdf

4 MOST ENDANGERED WHITETAIL DESTINATIONS IN AMERICA

Mark Kenyon

MARK KENYON Jun 3, 2022

4 Most Endangered Whitetail Destinations in America

It would not be hyperbole to say that we’re quite possibly living in the “golden age” of whitetail deer hunting.

Deer populations might be higher now than ever before and, at least since records have been kept, bigger, older bucks have never been more numerous. Hunters smash world and state records every year. The good times sure seem to be rolling.

But this isn’t true across all aspects or locales within the whitetail range, nor is it guaranteed to remain true into the future. All good things can and do come to an end.

The future of deer and deer hunting, as is the case with almost every aspect of the natural world today, exists on a precipice. Serious threats like disease, habitat loss, resource management, and public opinion all loom on the horizon. Four specific threatened locations, in particular, stand out as representative of larger issues threatening our nation’s deer hunting future. These are, in our estimation, the four most endangered whitetail destinations in America.

Read on for an introduction to these special yet threatened whitetail locales. And find out what we can do as deer hunters and stewards of the land to address the challenges in these specific locations and across the nation.

SOUTHWESTERN WISCONSIN

Greatest Threat: Chronic Wasting Disease

Southwest Wisconsin, a world-renowned big buck destination, is also ground zero for chronic wasting disease. The 100% fatal neurological disease impacting whitetails and other deer species has now spread to 29 states across the country. CWD is widely recognized as possibly the greatest existential threat to the future of whitetail hunting, and no place is it more ubiquitous than Wisconsin’s driftless area.

In some regions here, hunters are observing population-level impacts and CWD prevalence rates have hit as high as 30%. In more practical terms, this means that some areas of the whitetail-crazy state of Wisconsin might be experiencing the beginnings of downward trends in populations due to CWD. Almost one in three deer tested in these areas are testing positive. While CWD’s large-scale impact on deer populations is no joke, an equally concerning risk is the impact that positive tests have on the desire to hunt and eat deer at all. While transmission from deer to humans hasn’t been documented, it’s theoretically possible—akin to what happened with Mad Cow Disease in the 1990s. For this reason, the CDC currently advises hunters not to consume venison from a CWD-positive deer. The result of all this is that a lot of hard-earned venison is getting thrown in the dump already, and things, hypothetically, stand to worsen.

This worst-in-class state of affairs is partly due to a passive approach to CWD management that Wisconsin adopted in 2012, moving away from their “earn a buck” rule, stopping targeted population controls, and making testing in known CWD areas only voluntary.

“Because of the passive management approach taken by Wisconsin, CWD is endemic to five southwest counties, has spread to surrounding counties, and has been found in 38 of the state’s 72 counties,” said southwestern Wisconsin resident, hunter, and land consultant Doug Duren. “In some areas in those counties where prevalence is being studied, over 50% of adult bucks and over 35% of adult does are CWD positive.”

In conversations with other area residents, Duren heard anecdotal reports of seeing fewer older deer and mature bucks, increasing numbers of late-stage infected animals in need of putting down, and already dead deer. “One member of a group of hunters with a lease in Iowa County, Wisconsin told me they decided to give up their lease and find opportunity elsewhere as every buck they killed in the past three years tested positive for CWD,” he said. “This is a cautionary tale.”

While there is no single simple fix to this problem, the recently introduced Chronic Wasting Disease Research and Management Act would designate $35 million in badly needed funding for CWD research and another $35 million for management and surveillance that would certainly help the situation in Wisconsin and beyond. Click here to let your senators know this is an issue of supreme importance to deer hunters in your state.

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TEXAS

Greatest Threat: Captive Deer Industry

The great state of Texas sports one of the most robust and proud deer hunting cultures in the nation, but it’s also home to what some consider the greatest threat to deer hunting in all of America: the captive deer industry.

The debate around the captive deer industry is complicated, long-standing, and fraught, but the issues can be distilled into two main categories. First is the well-documented risk of spreading CWD by way of the transfer and sale of captive deer. Second is the negative impact that captive deer shooting facilities, and the media created around them, can have on the public perception of hunting in America and the North American Model of Conservation.

Texas is home to more captive deer facilities than any other state by a long shot, with 858 locations. The conditions present at such facilities, with high numbers of animals in close quarters, are well known to be a perfect storm for the spread of CWD. Not to mention the fact that given the transactional nature of captive deer breeding, many animals are sold and shipped across wide swaths of the country, potentially cross-contaminating new herds of deer all along the way.

While there have been increasing amounts of testing and monitoring of these herds for CWD, the effectiveness of these efforts are feared to be sub-par at best. “The profit motive is so great, it is common for deer breeders to hide infections, or simply not test, and thus spread the disease,” writes Whit Fosborg, CEO of the Theodore Roosevelt Conservation Partnership.

All of this makes Texas a likely ground zero for future CWD issues, a perfect example being a 2021 investigation that identified the release of more than 1,700 deer from seven Texas captive deer facilities that could have been exposed to chronic wasting disease. “Overwhelmingly, the CWD hot zone maps radiate from captive facilities across the state,” said Texas resident and bowhunter K.C. Smith.

Furthermore, the proliferation of captive deer facilities and “canned shooting preserves” threaten to shine a poor light on the larger hunting public, potentially hemorrhaging support for the free-range pursuit of whitetails in Texas and elsewhere. While the vast majority of non-hunters support hunting for food, those figures reverse when considering “trophy hunting.” Animals that are custom-bred to grow the largest antlers possible and then housed in high-fenced small enclosures and sold off to be shot by the highest bidder represents the most egregious example of what trophy hunting could be percieved as. Regardless of whether or not most high-fence facilities fit this description, the worst offenders are unfortunately what most people notice. We as whitetail hunters risk being defined by our most fringe element, especially in the Lone Star state.

It’s important to note that many of the high fence deer facilities in Texas very well might be well-managed and owned by good honest deer-loving people, Smith was quick to remind me. This is not as cut and dry of an issue as some non-Texans want to believe it is.

“I have an easy set of values to live by: don’t hurt people and don’t take their stuff,” he said. “However, when the deer ‘owned’ by another person are threatening to take away the future of my kids’ and everyone’s deer hunting, something must be done.”

Support for the Chronic Wasting Disease Research and Management Actwill help just as much here as in Wisconsin, as would advocating for greater oversightof the captive deer industry in Texas and beyond.

https://www.themeateater.com/wired-to-hunt/whitetail-management/4-most-endangered-whitetail-destinations-in-america

***> TEXAS HISTORY OF CWD <***

Singeltary telling TAHC, that CWD was waltzing into Texas from WSMR around Trans Pecos region, starting around 2001, 2002, and every year, there after, until New Mexico finally shamed TAHC et al to test where i had been telling them to test for a decade. 2012 cwd was detected first right there where i had been trying to tell TAHC for 10 years.

***> Singeltary on Texas Chronic Wasting Disease CWD TSE Prion History <***

http://chronic-wasting-disease.blogspot.com/2017/08/texas-chronic-wasting-disease-cwd-tse.html

FRIDAY, JULY 15, 2022

Texas Chronic Wasting Disease CWD TSE Prion Positives Increase By 8 to 369 TOTAL Confirmed To Date

https://chronic-wasting-disease.blogspot.com/2022/07/texas-chronic-wasting-disease-cwd-tse.html

MONDAY, AUGUST 01, 2022

TEXAS Letter from Trophy Ranch to Governor Abbott about CWD TSE Prion

https://chronic-wasting-disease.blogspot.com/2022/08/texas-letter-from-trophy-ranch-to.html

Proposed Amendments to CWD Zone Rules

Your opinions and comments have been submitted successfully.

Thank you for participating in the TPWD regulatory process.

https://tpwd.texas.gov/business/feedback/public_comment/proposals/202208_cwd.phtml

THURSDAY, AUGUST 04, 2022

Texas Proposed Amendments to CWD Zone Rules Singeltary Submission

https://chronic-wasting-disease.blogspot.com/2022/08/texas-proposed-amendments-to-cwd-zone.html

Research Project: Elucidating the Pathobiology and Transmission of Transmissible Spongiform Encephalopathies

Location: Virus and Prion Research

Title: Exploring the possibility of CWD transmission through artificial insemination of semen from CWD positive bucks

Author

item Cassmann, Eric

item Greenlee, Justin

Submitted to: North American Deer Farmer

Publication Type: Trade Journal

Publication Acceptance Date: 7/1/2022

Publication Date: 7/20/2022

Citation: Cassmann, E.D., Greenlee, J.J. 2022. Exploring the possibility of CWD transmission through artificial insemination of semen from CWD positive bucks. North American Deer Farmer. p. 107-109.

Interpretive Summary:

Technical Abstract: Artificial insemination is a popular method for herd management and reproduction in the cervid farming industry. There are numerous benefits including increased access to superior genetics, convenience, and increased farm revenue. In this article, we summarize the research that is underway to determine if semen from a CWD infected buck can transmit the disease. Some research has already been performed on the reproductive transmission of CWD in cervids. Scientists from Colorado State University used Muntjac deer to demonstrate that CWD positive does could transmit CWD to their fawns (1). In the study, Muntjac does were bred to CWD negative bucks. At the time of breeding, does were either in the early or late stage of CWD infection. Fawns from both doe groups were positive for CWD. More recent laboratory experiments on semen from CWD positive bucks have demonstrated the presence of CWD prions (2). Researchers used an amplification technique called PMCA (protein misfolding cyclic amplification). The technique amplifies low levels of CWD prions to a point where conventional antibody methods can detect them. The caveat to the discovery of CWD prions in semen is that we’re unsure if the amount of CWD prions in semen is biologically relevant. In other words, is the level of CWD prions in semen sufficient to be infectious and cause disease in deer? In our present study, we are trying to answer that question. We obtained semen from a CWD positive buck. The semen was confirmed to be PMCA positive. For the study, we used the transcervical insemination method in three does. As of June 19th, a single fawn was born. Shortly after birth the fawn was separated to prevent environment CWD exposure. We are assessing both the does and the fawn for the development of CWD. The experiment is expected to last several years, and periodic sampling will help monitor progress. A second phase of the study will investigate the absolute susceptibility of white-tailed deer does to CWD after transcervical and/or vaginal exposure to large amounts of CWD prions. We plan to expose two does to brain suspension from a CWD positive deer. These does will also be monitored long term for the development of disease. If these does remain negative, it would indicate that CWD transmission to the dam is highly unlikely via reproductive tract exposure.

https://www.ars.usda.gov/research/publications/publication/?seqNo115=395853

WEDNESDAY, SEPTEMBER 07, 2022

Exploring the possibility of CWD transmission through artificial insemination of semen from CWD positive bucks

https://chronic-wasting-disease.blogspot.com/2022/09/exploring-possibility-of-cwd.html

Published: 06 September 2021

***> Chronic wasting disease: a cervid prion infection looming to spillover

Alicia Otero, Camilo Duque Velásquez, Judd Aiken & Debbie McKenzie

Veterinary Research volume 52, Article number: 115 (2021)

https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-021-00986-y

October 6th-12th, 126th Meeting 2022 Resolutions

RESOLUTION NUMBER: 30 Approved

SOURCE: COMMITTEE ON WILDLIFE

SUBJECT MATTER: Chronic Wasting Disease Carcass Disposal Dumpster Management and Biosecurity

BACKGROUND INFORMATION:

State and tribal wildlife agencies may identify collection points (dumpsters) within an identified chronic wasting disease (CWD) management zone for the disposal of hunter-harvested cervid carcasses to remove potentially infected carcasses off the landscape for disposal by an approved method (Gillin & Mawdsley, 2018, chap.14). However, depending on their placement and maintenance these dumpsters could potentially increase the risk of CWD transmission.

In several different states, photographic evidence has shown dumpsters in state identified CWD management zones overflowing with deer carcasses and limbs scattered on the land nearby. This could provide an opportunity for scavengers to potentially move infected carcass material to non-infected zones or increase contamination of the ground material around the dumpster’s location.

Federal guidance does not explicitly address uniform standards for collection locations for carcasses of free-ranging cervids; however, the United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services Program Standards on CWD outlines procedures for carcass disposal, equipment sanitation, and decontamination of premises for captive cervid facilities.

RESOLUTION:

The United States Animal Health Association urges the Association of Fish and Wildlife Agencies (AFWA), Wildlife Health Committee to further refine the AFWA Technical Report on Best Management Practices for Prevention, Surveillance, and Management of Chronic Wasting Disease; Chapter 14, Carcass Disposal to address the placement and management of chronic wasting disease carcass disposal dumpsters or other carcass collection containers.

Reference:

1. Gillin, Colin M., and Mawdsley, Jonathan R. (eds.). 2018. AFWA Technical Report on Best Management Practices for Surveillance, Management and Control of Chronic Wasting Disease. Association of Fish and Wildlife Agencies, Washington, D. C. 111 pp.

https://www.usaha.org/upload/Resolution/2022/2022_Resolution_30_CWD_Dumpste.pdf

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

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.

https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2091286

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 aDepartment of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine & Hotchkiss Brain Institute; University of Calgary, Calgary, Canada; bInstitute of Neuropathology, Medical Faculty, Saarland University, Homburg/Saar, Germany

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.

Funded by: The National Institutes of Health, USA, and the Alberta Prion Research Institute/Alberta Innovates Canada. Grant number: 1R01NS121016-01; 201,600,023

Acknowledgement: We thank Umberto Agrimi, Istituto Superiore di Sanità, Rome, Italy, and Michael Beekes, Robert-Koch Institute Berlin, Germany, for providing the bank vole model. We thank the University of Calgary animal facility staff and Dr. Stephanie Anderson for animal care.

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

aDepartment of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine; Hotchkiss Brain Institute; University of Calgary, Calgary, Canada; bUniversité Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France; cDepartment of Biological Sciences, Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada

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.

Funded by: We are grateful for financial support from the Natural Sciences and Engineering Research Council of Canada, the National Institutes of Health, Genome Canada, and the Alberta Prion Research Institute. SG is supported by the Canada Research Chairs program.

Acknowledgement: We thank Dr. Trent Bollinger, WCVM, University of Saskatchewan, Saskatoon, Canada, for providing brain tissue from the WTD-116AG isolate, Dr. Stéphane Haïk, ICM, Paris, France, for providing brain tissue from vCJD and sCJD cases, and Dr. Umberto Agrimi, Istituto Superiore di Sanità, Italy, for the bank vole model. We thank animal facility staff for animal care, Dr. Stephanie Anderson for veterinary oversight, and Yo-Ching Cheng for preparing recombinant PrP substrates. Thank you to Dr. Stephanie Booth and Jennifer Myskiw, Public Health Agency of Canada, Canada.

The chronic wasting disease agent from white-tailed deer is infectious to humanized mice after passage through raccoons

Eric Cassmanna, Xu Qib, Qingzhong Kongb, and Justin Greenleea

aNational Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA, USA bDepartments of Pathology, Neurology, National Center for Regenerative Medicine, and National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, USA

Aims: Evaluate the zoonotic potential of the raccoon passaged chronic wasting disease (CWD) agent in humanized transgenic mice in comparison with the North American CWD agent from the original white-tailed deer host.

Material and Methods: Pooled brain material (GG96) from a CWD positive herd was used to oronasally inoculate two white-tailed deer with wild-type prion protein genotype and intracranially inoculate a raccoon. Brain homogenates (10% w/v) from the raccoon and the two white-tailed deer were used to intracranially inoculate separate groups of transgenic mice that express human prion protein with methionine (M) at codon 129 (Tg40h). Brains and spleens were collected from mice at experimental endpoints of clinical disease or approximately 700 days post-inoculation. Tissues were divided and homogenized or fixed in 10% buffered neutral formalin. Immunohistochemistry, enzyme immunoassay, and western blot were used to detect misfolded prion protein (PrPSc) in tissue.

Results: Humanized transgenic mice inoculated with the raccoon passaged CWD agent from white-tailed deer exhibited a 100% (12/12) attack rate with an average incubation period of 605 days. PrPScwas detected in brain tissue by enzyme immunoassay with an average optical density of 3.6/4.0 for positive brains. PrPScalso was detected in brain tissue by western blot and immunohistochemistry. No PrPScwas detected in the spleens of mice inoculated with the raccoon passaged CWD agent. Humanized mice inoculated with the CWD agent from white-tailed deer did not have detectable PrPScusing conventional immunoassay techniques.

Conclusions: The host range of the CWD agent from white-tailed deer was expanded in our experimental model after one passage through raccoons.

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.

Acknowledgement: We thank Quazetta Brown, Lexi Frese, Rylie Frese, Kevin Hassall, Leisa Mandell, and Trudy Tatum for providing excellent technical support to this project.

Stable and highly zoonotic cervid prion strain is possible

Manuel Camacho, Xu Qi, Liuting Qing, Sydney Smith, Jieji Hu, Wanyun Tao, Ignazio Cali, and 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 some areas. Multiple in vitro conversion experiments and in vivo animal studies suggest that the CWD-to-human transmission barrier is not unbreakable. A major 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.

Material and Methods: We inoculated a few sCJD brain samples into cervidized transgenic mice, which were intended as negative controls for bioassays of brain tissues from sCJD cases who had hunted or consumed vension from CWD-endemic states. Some of these mice became infected and their brain tissues were further examined by 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 CJDElkPrPin transgenic mice expressing human PrP (Tg40h). We passaged CJDElkPrPtwo more times in the Tg12 mice. We found that such second and third passage CJDElkPrPprions also led to 100% infection in the Tg40h mice. In contrast, we and others found zero or poor transmission of natural elk CWD isolates in humanized mice, despite that natural elk CWD isolates and CJDElkPrPshare the same elk PrP sequence.

Conclusions: Our data demonstrate that highly zoonotic cervid prion strains are not only possible but also can be stably maintained in cervids and that CWD zoonosis is prion strain-dependent.

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, respectively.

Adaptation of chronic wasting disease (CWD) prion strains in hosts with different PRNP genotypes

Camilo Duque Velasqueza,c, Elizabeth Triscotta,c, Chiye Kima,c, Diana Morenoa,c, Judd Aikenb,c, and Debbie McKenziea,c

aDepartment of Biological Science, University of Alberta, Edmonton, AB T6G 2G8, Canada; bDepartment of Agriculture, Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2G8, Canada; cCentre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada

Aims: The contagious nature of CWD epizootics and the PrPCamino acid variation of cervids (and susceptible sympatric species) guarantee the expansion of prion conformational diversity and selective landscapes where new strains can arise. CWD strains can have novel transmission properties including altered host range that may increase zoonotic risk as circulating strains diversify and evolve. We are characterizing the host adaptability of characterized CWD strains as well as CWD isolates from different cervid species in various enzootic regions.

Material and Methods: Characterized CWD strains as well as a number of isolates from hunter-harvested deer were bioassayed in our rodent panel (transgenic mice expressing cervid alleles G96, S96 and H95-PrPC, elk PrPC, bovine PrPC, and both hamsters and non-transgenic laboratory mice). Strain characteristics were compared using computer based scoring of brain pathology (e.g. PrPCWDbrain distribution), western blot and protein misfolding cyclic amplification (PMCA).

Results: Transmission of various isolates resulted in the selection of strain mixtures in hosts expressing similar PrPC, particularly for polymorphic white-tailed deer and for Norwegian reindeer. As of the second passage, transmission of P153 moose prions from Norway has not resulted in emergence of strains with properties similar to any North American CWD strains in our taxonomic collection (Wisc-1, CWD2, H95+and 116AG).

Conclusions: Our data indicates polymorphic white-tailed deer can favor infection with more than one strain. Similar to transmission studies of Colorado CWD isolates from cervids expressing a single PrPCprimary structure, the isolate from Norway reindeer (V214) represents a strain mixture, suggesting intrinsic strain diversity in the Nordfjella epizootic. The diversity of CWD strains with distinct transmission characteristics represents a threat to wildlife, sympatric domestic animals and public health.

Funded by: Genome Canada and Genome Alberta (Alberta Prion Research Institute and Alberta Agriculture & Forestry); NSERC Grant number: #LSARP 10205; NSERC RGPIN-2017-05539

Acknowledgement: We would like to thank Margo Pybus (Alberta Environment and Parks) Trent Bollinger (University of Saskatchewan) for providing us with tissue samples from hunter-harvested deer and Sylvie Benestad for providing moose and reindeer samples.

Application of PMCA to understand CWD prion strains, species barrier and zoonotic potential

Sandra Pritzkowa, Damian Gorskia, Frank Ramireza, Fei Wanga, Glenn C. Tellingb, Justin J. Greenleec, Sylvie L. Benestadd, and Claudio Sotoa aDepartment of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA; bDepartment of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA; cVirus and Prion Research Unit, United States Department of Agriculture, Ames, Iowa, USA; dNorwegian Veterinary Institute, OIE Reference Laboratory for CWD, Ås, Norway

Aims: Chronic wasting disease (CWD) is a prion disease affecting various species of cervids that continues to spread uncontrollably across North America and has recently been detected in Scandinavia (Norway, Sweden and Finland). The mechanisms responsible for the natural transmission of CWD are largely unknown. Furthermore, the risk of CWD transmission to other species, including humans, is also unknown and remains a dangerous enigma. In this study, we investigated the potential of CWD prions to infect several other animal species (sheep, cattle, pig, hamster, and mouse) including humans, by examining their capacity to convert the normal prion protein of distinct species in a PMCA reaction. Moreover, we also investigated whether the in vivo passage of CWD through intermediate species alters their capacity for zoonotic transmission, which may represent a major hazard to human health.

Material and Methods: For these studies, we used brain material from CWD-infected white-tailed deer (Odocoileus virginianus), elk (Cervus canadensis), and mule deer (Odocoileus hemionus) as species native to North America. We also used CWD-infected Moose (Alces alces), reindeer (Rangifer tarandus) and red deer (Cervus elaphus) as Norwegian cervids. We also used brains from cattle, sheep and pigs experimentally infected by CWD. To study interspecies-transmission and zoonotic potential, samples were tested via PMCA for the conversion of PrPCinto PrPScusing different combinations of inoculum and host species. Based on these analyses we estimated the spillover and zoonotic potential for different CWD isolates. We define and quantify spillover and zoonotic potential indices as the efficiency by which CWD prions sustain prion generation in vitro at the expense of normal prion proteins from various mammals and human, respectively.

Results: Our results show that prions from some cervid species, especially those found in Northern Europe, have a higher potential to transmit disease characteristics to other animals. Conversely, CWD-infected cervids originated in North America appear to have a greater potential to generate human PrPSc. We also found that in vivo transmission of CWD to cattle, but not to sheep or pigs substantially increases the ability of these prions to convert human PrPCby PMCA.

Conclusions: Our findings support the existence of different CWD prion strains with distinct spillover and zoonotic potentials. We also conclude that transmission of CWD to other animal species may increase the risk for CWD transmission to humans. Our studies may provide a tool to predict the array of animal species that a given CWD prion could affect and may contribute to understanding the risk of CWD for human health.

Funded by: National Institute of Health Grant number: P01 AI077774

Generation of human chronic wasting disease in transgenic mice

Zerui Wanga, Kefeng Qinb, Manuel V. Camachoa, Ignazio Cali a,c, Jue Yuana, Pingping Shena, Tricia Gillilanda, Syed Zahid Ali Shaha, Maria Gerasimenkoa, Michelle Tanga, Sarada Rajamanickama, Anika Yadatia, Lawrence B. Schonbergerd, Justin Greenleee, Qingzhong Konga,c, James A. Mastriannib, and Wen-Quan Zoua,c

aDepartment of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, USA; bDepartment of Neurology and Center for Comprehensive Care and Research on Memory Disorders, the University of Chicago Pritzker School of Medicine, Chicago, USA; cNational Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; dDivision of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, USA; eVirus and Prion Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, 1920 Dayton Avenue, Ames, IA, USA

Aims: Chronic wasting disease (CWD) results from the accumulation of an infectious misfolded conformer (PrPSc) of cellular prion protein (PrPC) in the brains of deer and elk. It has been spreading rapidly throughout many regions of North America, exported inadvertently to South Korea, and more recently identified in Europe. Mad cow disease has caused variant Creutzfeldt-Jakob disease (vCJD) in humans and is currently the only known zoonotic prion disease. Whether CWD is transmissible to humans remains uncertain. The aims of our study were not only to confirm whether CWD prion isolates can convert human brain PrPCinto PrPScin vitro by serial protein misfolding cyclic amplification (sPMCA) but also to determine whether the sPMCA-induced CWD-derived human PrPScis infectious.

Material and Methods: Eight CWD prion isolates from 7 elks and 1 deer were used as the seeds while normal human brain homogenates containing either PrP-129 MM (n = 2) or PrP-129 VV (n = 1) were used as the substrates for sPMCA assay. A normal elk brain tissue sample was used as a negative control seed. Two lines of humanized transgenic (Tg) mice expressing either human PrP-129VV or −129 MM polymorphism were included for transmission studies to determine the infectivity of PMCA-amplified PrPSc. Wester blotting and immunohistochemistry and hematoxylin & eosin staining were used for determining PrPScand neuropathological changes of inoculated animals.

Results: We report here the generation of the first CWD-derived infectious human PrPScusing elk CWD PrPScto initiate conversion of human PrPCfrom normal human brain homogenates with PMCA in vitro. Western blotting with a human PrP selective antibody confirmed that the PMCA-generated protease-resistant PrPScwas derived from the human brain PrPCsubstrate. Two lines of humanized transgenic mice expressing human PrPCwith either Val or Met at the polymorphic codon 129 developed clinical prion disease following intracerebral inoculation with the PMCA-generated CWD-derived human PrPSc. Diseased mice exhibited distinct PrPScpatterns and neuropathological changes in the brain.

Conclusions: Our study, using PMCA and animal bioassays, provides the first evidence that CWD PrPSchas the potential to overcome the species barrier and directly convert human PrPCinto infectious PrPScthat can produce bona fide prion disease when inoculated into humanized transgenic mice.

Funded by: CJD Foundation and NIH

Mortality surveillance of persons potentially exposed to chronic wasting disease

R.A. Maddoxa, R.F. Klosb, L.R. Willb, S.N. Gibbons-Burgenerb, A. Mvilongoa, J.Y. Abramsa, B.S. Applebyc, L.B. Schonbergera, and E.D. Belaya aNational Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, USA; bWisconsin Department of Health Services (WDHS), Division of Public Health, Madison, USA; cNational Prion Disease Pathology Surveillance Center (NPDPSC), Case Western Reserve University, Cleveland, USA

Aims: It is unknown whether chronic wasting disease (CWD), a prion disease of cervids, can infect people, but consumption of meat from infected animals would be the most likely route of transmission. Wisconsin Department of Health Services, Division of Public Health (WDHS) personnel maintain a database consisting of information collected from hunters who reported eating, or an intention to eat, venison from CWD-positive cervids. These data, collected since 2003, allow for the evaluation of causes of mortality in individuals potentially exposed to CWD.

Material and Methods: The WDHS database contains the name, date of birth, when available, year of CWD-positive deer harvest, and city and state of residence for each potentially exposed individual. The database also includes information on how the deer was processed (self-processed or by a commercial operator) and when applicable, names of others with whom the venison was shared. Duplicate entries (i.e., those who consumed venison from CWD-positive deer in multiple hunt years) are determined by first name, last name, and date of birth. All names in the database are cross-checked with reported cases of human prion disease in Wisconsin and cases in the National Prion Disease Pathology Surveillance Center (NPDPSC) diagnostic testing database. Persons with date of birth available are also cross-checked with prion disease decedents identified through restricted-use national multiple cause-of-death data via a data use agreement with the National Center for Health Statistics (NCHS).

Results: The database currently consists of 1561 records for hunt years 2003–2017 and 87 additional records for 2018–2019. Of these, 657 records have accompanying date of birth; 15 entries were removed as duplicates leaving 642 unique individuals. Of these individuals, 278 of 426 (66%) who ate venison from a CWD-positive deer and provided processing information reported self-processing. No matches were found among any persons in the database cross-checked with WDHS human prion disease surveillance data, NPDPSC data (February 2022 update), and NCHS data through 2020.

Conclusions: Because of the linkage of person and CWD-positive animal in the WDHS database, reviewing the cause of mortality in potentially exposed persons is possible. The number of individuals cross-checked so far is likely only a small percentage of those potentially exposed to CWD in Wisconsin, and many more years of vital status tracking are needed given an expected long incubation period should transmission to humans occur. Nevertheless, the findings of this ongoing review are thus far reassuring.

Prion disease incidence, United States, 2003–2020

R.A. Maddoxa, M.K. Persona, K. Kotobellib, A. Mvilongoa, B.S. Applebyb, L.B. Schonbergera, T.A. Hammetta, J.Y. Abramsa, and E.D. Belaya aNational Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, USA; bNational Prion Disease Pathology Surveillance Center (NPDPSC), Case Western Reserve University, Cleveland, USA

Aims: Mortality data, in conjunction with neuropathological and genetic testing results, are used to estimate prion disease incidence in the United States.

Material and Methods: Prion disease decedents for 2003–2020 were identified from restricted-use U.S. national multiple cause-of-death data, via a data use agreement with the National Center for Health Statistics, and from the National Prion Disease Pathology Surveillance Center (NPDPSC) database. NPDPSC decedents with neuropathological or genetic test results positive for prion disease for whom no likely match was found in the NCHS multiple cause-of-death data were added as cases for incidence calculations, while those with negative neuropathology results but with cause-of-death data indicating prion disease were removed. Unmatched cases in the NPDPSC database lacking neuropathological testing but with a positive real-time quaking-induced conversion (RT-QuIC) test result were additionally assessed. Age-specific and age-adjusted average annual incidence rates were calculated from the combined data; the year 2000 as the standard population and the direct method were used for age-adjustment.

Results: A total of 7,921 decedents were identified as having prion disease during 2003–2020 for an age-adjusted average annual incidence of 1.2 per million population. The age-adjusted incidence between males and females (1.3 and 1.1 per million, respectively) differed significantly (p < 0.0001). The age-specific average annual incidence among those <55 and ≥55 years of age was 0.2 and 4.8 per million, respectively; incidence among those ≥65 was 6.1 per million. Eighteen cases were <30 years of age for an age-specific incidence of 8.0 per billion; only 6 of these very young cases were sporadic (3 sporadic CJD, 3 sporadic fatal insomnia), with the rest being familial (9), variant (2), or iatrogenic (1). The age-adjusted annual incidence for the most recent year of data, 2020, was 1.3 per million. However, assessment of RT-QuIC positive cases lacking neuropathology in the NPDPSC database suggested that approximately 20% more cases may have occurred in that year; the addition of a subset of these cases that had date of death information available (n = 44) increased the 2020 rate to 1.4 per million.

Conclusions: Mortality data supplemented with the results of neuropathological, CSF RT-QuIC, and genetic testing can be used to estimate prion disease incidence. However, the identification in the NPDPSC database of RT-QuIC-positive cases lacking date of death information suggests that this strategy may exclude a number of probable prion disease cases. Prion disease cases <30 years of age, especially those lacking a pathogenic mutation, continue to be very rare.

Shedding of Chronic Wasting Disease Prions in Multiple Excreta Throughout Disease Course in White-tailed Deer

Nathaniel D. Denkersa, Erin E. McNultya, Caitlyn N. Krafta, Amy V. Nallsa, Joseph A. Westricha, Wilfred Goldmannb, Candace K. Mathiasona, and Edward A. Hoovera

aPrion Research Center, College of Veterinary Medicine and Biological Sciences, Department of Microbiology, Immunology, and Pathology; Colorado State University, Fort Collins, CO, USA; bDivision of Infection and Immunity, The Roslin Institute and the Royal Dick School of Veterinary Studies, University of Edinburgh, Midlothian, UK

Aims: Chronic wasting disease (CWD) now infects cervids in South Korea, North America, and Scandinavia. CWD is unique in its efficient transmission and shedding of prions in body fluids throughout long course infections. Questions remain as to the magnitude of shedding and the route of prion acquisition. As CWD continues to expand, the need to better understand these facets of disease becomes more pertinent. The purpose of the studies described was to define the longitudinal shedding profile of CWD prions in urine, saliva, and feces throughout the course of infection in white-tailed deer.

Material and Methods: Twelve (12) white-tailed deer were inoculated with either 1 mg or 300ng of CWD. Urine, saliva, and feces were collected every 3-month post-inoculation (MPI) throughout the study duration. Cohorts were established based on PNRP genotype: codon 96 GG (n = 6) and alternate codons 96 GS (n = 5) & 103NT (n = 1). Urine and saliva were analyzed using iron-oxide magnetic extraction (IOME) and real-time quaking induced conversion (RT-QuIC)(IQ). Feces were subjected to IOME, followed by 4 rounds protein misfolding cyclic amplification (PMCA) with products analyzed by RT-QuIC (IPQ). To determine whether IPQ may be superior to IQ, a subset of urine and saliva were also tested by IPQ. Results were compared with clinical disease status.

Results: Within the 96 GG cohort, positive seeding activity was detected in feces from all deer (100%), in saliva from 5 of 6 (83%), and in urine from 4 of 6 (66%). Shedding in all excreta occurred at, or just after, the first positive tonsil biopsy result. In the 96 GS/103NT cohort, positive seeding activity could be detected in feces from 3 of 6 (50%) deer, saliva in 2 of 6 (33%), and urine in 1 of 6 (16%). Shedding in excreta was detected >5 months after the first tonsil positive result. Four of six 96 GG deer developed clinical signs of CWD, whereas only 2 of the 96 GS/103NT did. Shedding was more frequently detected in deer with clinical disease. The IPQ protocol did not significantly improve detection in saliva or urine samples, however, it significantly augmented detection in feces by eliminating non-specific background commonly experienced with IQ. Negative control samples remained negative in samples tested.

Conclusions: These studies demonstrate: (a) CWD prion excretion occurs throughout infection; (2) PRNP genotype (GG≫GS/NT) influences the excreta shedding; and (3) detection sensitivity in excreta can vary with different RT-QuIC protocols. These results provide a more complete perspective of prion shedding in deer during the course of CWD infection.

Funded by: National Institutes of Health (NIH)

Grant number: RO1-NS061902-09 R to EAH, PO1-AI077774 to EAH, and R01-AI112956-06 to CKM

Acknowledgement: We abundantly thank Sallie Dahmes at WASCO and David Osborn and Gino D’Angelo at the University of Georgia Warnell School of Forestry and Natural Resources for their long-standing support of this work through provision of the hand-raised, CWD-free, white-tailed deer used in these studies

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

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.

Funded by: USDA

Grant number: AP20VSSPRS00C143

ATYPRION project: assessing the zoonotic potential of interspecies transmission of CWD isolates to livestock (preliminary results).

Enric Vidala,b, Juan Carlos Espinosac, Samanta Gilera,b, Montserrat Ordóñeza,b, Guillermo Canteroa,b, Vincent Béringued, Justin J. Greenleee, and Juan Maria Torresc

aUnitat mixta d’Investigació IRTA-UAB en Sanitat Animal. Centre de Recerca en Sanitat Animal (CReSA). Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, Catalonia; bIRTA. Programa de Sanitat Animal. Centre de Recerca en Sanitat Animal (CReSA). Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, Catalonia; cCentro de Investigación en Sanidad Animal, CISA-INIA-CSIC, Valdeolmos, Madrid, Spain; dMolecular Virology and Immunology, French National Research Institute for Agriculture, Food and Environment (INRAE), Université Paris-Saclay, Jouy-en-Josas, France; eVirus and Prion Research Unit, National Animal Disease Center, ARS, United States Department of Agriculture, Ames, IA, USA

Aims: Since variant Creutzfeldt-Jackob disease was linked to the consumption of bovine spongiform encephalopathy prions, the study of the pathobiological features of animal prions, particularly their zoonotic potential, is of great concern to the scientific community and public health authorities. Furthermore, interspecies transmission of prions has been demonstrated as a putative evolutionary mechanism for prions, that can lead to the emergence of new features including the ability to infect humans. For instance, small ruminants’ atypical scrapie prions, when propagated in a bovine or porcine host, can shift to a classical BSE phenotype thus posing a potential risk in case of human exposure. So far, no hard evidence of zoonotic transmission of cervids’ chronic wasting disease (CWD) to humans has been published, however experimental transmission to bovine, ovine and caprine hosts has been achieved. Our goal is to investigate if, once passaged through these domestic species, CWD prions might become infectious to humans.

Material and Methods: Different CWD isolates experimentally adapted to cattle, sheep and goat (Hamir et al, 2005, 2006, 2007, Greenlee et al 2012) have been intracerebrally inoculated to transgenic mouse models expressing the human cellular prion protein either homozygous for methionine or valine at codon 129 (Tg340-Met129 and Tg362-Val129). Additionally, inocula obtained from experimental transmission of elk CWD to ovinized (Tg501) and bovinized (BoTg110) transgenic mice, as well as white-tailed deer CWD to BoTg110 mice, are currently being bioassayed in both human PrPCtransgenic models.

Results and conclusions: No evidence of transmission has been found on first passage for bovine adapted elk and mule deer CWD to none of the humanized models. The remaining bioassays are ongoing without showing clinical signs yet, as well as second passages for the negative 1stpassages.

Funded by: La Marató de TV3 foundation. Grant number: ATYPRION (201,821–30-31-32)

https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2091286

PRION CONFERENCE 2022 ABSTRACTS CWD TSE PrP ZOONOSIS and ENVIRONMENTAL FACTORS

Chronic wasting disease detection in environmental and biological samples from a taxidermy site

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.

Funded by: USDA Grant number: AP20VSSPRS00C143

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.

Funded by: USDA Grant number: AP20VSSPRS00C143

Protein misfolding cyclic amplification (PMCA) as an ultra-sensitive technique for the screening of CWD prions in different sample types

Francisca Bravo‐Risia,b, Paulina Sotoa,b, Rebeca Benaventea, Hunter Reedc, Mitch Lockwoodc, Tracy Nicholsd, and Rodrigo Moralesa,b aDepartment of Neurology, The University of Texas Health Science Center at Houston, Houston, TX, USA; bCentro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile; cTexas Park and Wildlife Department, Texas, USA; dVeterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA

Chronic wasting disease (CWD) is a prion disease that affects farmed and free-ranging cervids. The infectious agent in CWD is a misfolded form of the prion protein (PrPSc) that promotes conformational changes in the host’s cellular prion protein (PrPC). Currently, definitive CWD status is confirmed in the brain and lymphoid tissues by immunohistochemistry. The limitation of this technique is its poor sensitivity. Protein misfolding cyclic amplification (PMCA) and real-time quaking-induced conversion (RT- QuIC) are ultra-sensitive techniques that overcome these issues. PMCA mimics the self- propagation of infectious prions in vitro through multiple incubation/sonication cycles, increasing the number of prion particles present in a given sample. The detection of proteinase K (PK) -resistant PrPScby PMCA has been performed in experimental and natural samples that might harbor subclinical levels of prions. These samples include several tissues, bodily fluids, excreta, and different manmade and natural materials, including mineral licks, soils, and plants. Aims: In this study, we highlight recent advances and contributions that our group has performed in the detection of CWD prions from samples collected in farmed and free-ranging cervids, as well as other specimens involving the environment that contains CWD-infected deer. Material and Methods: A set of diverse samples analyzed in this study were collected by USDA and TPWD personnel in breeding and taxidermy facilities, and deer breeding facilities. These included animal and environmental samples. Additional samples from free-ranging animals were provided by hunters. Results: The diverse range of samples successfully detected for CWD prion infection in this study include blood, semen, feces, obex, retropharyngeal lymph node, fetuses (neural and peripheral tissues) and gestational tissues, parasites, insects, plants, compost/soil mixtures, and swabs from trash containers. Importantly, these results helped to identify seeding-competent prions in places reported to be free of CWD. The levels of prion infectivity in most of these samples are currently being investigated. Conclusions: Our findings contribute to the understanding of the transmission dynamics and prevalence of CWD. In addition, our data have helped to identify CWD in areas previously considered to be free of CWD. We also demonstrate that PMCA is a powerful technique for the screening of biological and environmental samples. Overall, our research suggests that PMCA may be a useful tool to implement for the surveillance and management of CWD. Funded by: NIH/NIAID and USDA Grant number: 1R01AI132695 (NIH) and AP20VSSPRS00C143 (USDA)

Nasal bot: an emerging vector for natural chronic wasting disease transmission

Paulina Sotoa,b, Francisca Bravo-Risia,b, Carlos Kramma, Nelson Pereza, Rebeca Benaventea, J. Hunter Reedc, Mitch Lockwoodc, Tracy A. Nicholsd, 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 Park and Wildlife Department, Texas, USA; dVeterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA

Chronic wasting disease (CWD) is a fatal neurodegenerative disease that affects farmed and free-ranging cervids populations. The spread of CWD in cervids is thought to occur through the direct contact between cervids or through the exposure of naïve animals to contaminated environments. Parasites are known vectors of multiple diseases in animals. However, the potential role of parasites in CWD transmission remains unclear. Aims: The main objective of this study was to determine if CWD prions could be detected in the larvae of deer nasal bot flies, a common deer parasite, taken from CWD-infected white-tailed deer (Odocoileus virginianus). Methods: Bot fly larvae were collected from the nasal cavity of naturally infected CWD- positive or CWD non-detect white-tailed deer. The CWD seeding activity of the larvae was interrogated by PMCA. Prion infectivity was also evaluated in cervidized transgenic mouse bioassay (intra-cerebral administration in Tg1536 mice). Mice inoculated with bot larvae homogenate were sacrificed when they showed established signs of prion disease, or at extended periods after treatment (600 days). All inoculated mouse brains were evaluated for protease resistant prions to confirm clinical or sub-clinical infection. Bot larvae from CWD non-detect deer were used as controls. To further mimic environmental transmission, bot larvae homogenates were mixed with soils and plants were grown on them. Both plants and soils were tested for prion seeding activity. Results: PMCA analysis demonstrated CWD seeding activity in nasal bot larvae from captive and free-ranging white-tailed deer. CWD-contaminated bots efficiently infected transgenic mice, with attack rates and incubation periods suggesting high infectivity titers. Further analyses of treated animals (biochemical characterization of protease resistant prions and immunohistochemistry) confirmed prion infection. Analyses on dissected parts of the bot larvae demonstrate that the infectivity is concentrated in the larvae cuticle (outer part). Nasal bot larvae extracts mixed with

soils showed seeding activity by PMCA. Interestingly, plants grown in soil contaminated with the nasal bot larvae extract were found to produce seeding activity by PMCA. Conclusion: In this study we described for the first time that deer nasal bot larvae from CWD-infected deer carry high CWD infectivity titers. We also demonstrate that CWD prions in these parasites can interact with other environmental components relevant for disease transmission. Considering this information, we propose that deer nasal bot larvae could act as vectors for CWD transmission in wild and farming settings. Funded by: NIH/NIAID and USDA/APHIS Grant number: R01AI132695 and AP20VSSPRS00C143 PRION 2022 ABSTRACTS, AND A BIG THANK YOU TO On behalf of the Prion2020/2022 Congress Organizing Committee and the NeuroPrion Association, we heartily invite you to join us for the International Conference Prion2020/2022 from 13.-16. September 2022 in Göttingen.

Prion 2022 Conference abstracts: pushing the boundaries

https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2091286

Shedding of Chronic Wasting Disease Prions in Multiple Excreta Throughout Disease Course in White-tailed Deer

Nathaniel D. Denkersa, Erin E. McNultya, Caitlyn N. Krafta, Amy V. Nallsa, Joseph A. Westricha, Wilfred Goldmannb, Candace K. Mathiasona, and Edward A. Hoovera

Funded by: National Institutes of Health (NIH)

Grant number: RO1-NS061902-09 R to EAH, PO1-AI077774 to EAH, and R01-AI112956-06 to CKM

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.

Funded by: NIH

Grant number: R01AI132695

https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2091286

ENVIRONMENT FACTORS FOR THE TRANSMISSION OF CWD TSE PRP

Sensitive detection of chronic wasting disease prions recovered from environmentally relevant surfaces

Environment International

Available online 13 June 2022, 107347

Environment International

Sensitive detection of chronic wasting disease prions recovered from environmentally relevant surfaces

Qi Yuana Gag e Rowdenb Tiffany M.Wolfc Marc D.Schwabenlanderb Peter A.LarsenbShannon L.Bartelt-Huntd Jason C.Bartza

a Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, 68178, United States of America

b Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, 55108, United States of America

c Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, 55108, United States of America

d Department of Civil and Environmental Engineering, Peter Kiewit Institute, University of Nebraska-Lincoln, Omaha, Nebraska, 68182, United States of America

Received 26 April 2022, Revised 8 June 2022, Accepted 9 June 2022, Available online 13 June 2022.

https://doi.org/10.1016/j.envint.2022.107347

Get rights and content

Under a Creative Commons license Open access

Highlights • An innovative method for prion recovery from swabs was developed.

• Recovery of prions decreased as swab-drying time was increased.

• Recovery of CWD prions from stainless steel and glass was approximately 30%.

• RT-QuIC enhanced CWD prion detection by 4 orders of magnitude.

• Surface-recovered CWD prion was sufficient for efficient RT-QuIC detection.

Abstract

Chronic wasting disease (CWD) has been identified in 30 states in the United States, four provinces in Canada, and recently emerged in Scandinavia. The association of CWD prions with environmental materials such as soil, plants, and surfaces may enhance the persistence of CWD prion infectivity in the environment exacerbating disease transmission. Identifying and quantifying CWD prions in the environment is significant for prion monitoring and disease transmission control. A systematic method for CWD prion quantification from associated environmental materials, however, does not exist. In this study, we developed an innovative method for extracting prions from swabs and recovering CWD prions swabbed from different types of surfaces including glass, stainless steel, and wood. We found that samples dried on swabs were unfavorable for prion extraction, with the greatest prion recovery from wet swabs. Using this swabbing technique, the recovery of CWD prions dried to glass or stainless steel was approximately 30% in most cases, whereas that from wood was undetectable by conventional prion immunodetection techniques. Real-time quake-induced conversion (RT-QuIC) analysis of these same samples resulted in an increase of the detection limit of CWD prions from stainless steel by 4 orders of magnitude. More importantly, the RT-QuIC detection of CWD prions recovered from stainless steel surfaces using this method was similar to the original CWD prion load applied to the surface. This combined surface swabbing and RT-QuIC detection method provides an ultrasensitive means for prion detection across many settings and applications.

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5. Conclusions

Chronic wasting disease is spreading in North America and it is hypothesized that in CWD-endemic areas environmental persistence of CWD prions can exacerbate disease transmission. The development of a sensitive CWD prion detection method from environmentally relevant surfaces is significant for monitoring, risk assessment, and control of CWD. In this study, we developed a novel swab-extraction procedure for field deployable sampling of CWD prions from stainless steel, glass, and wood. We found that extended swab-drying was unfavorable for extraction, indicating that hydrated storage of swabs after sampling aided in prion recovery. Recoverable CWD prions from stainless steel and glass was approximately 30%, which was greater than from wood. RT-QuIC analysis of the swab extracts resulted in an increase of the detection limit of CWD prions from stainless steel by 4 orders of magnitude compared to conventional immunodetection techniques. More importantly, the RT-QuIC detection of CWD prions recovered from stainless steel surfaces using this developed method was similar to the original CWD prion load without surface contact. This method of prion sampling and recovery, in combination with ultrasensitive detection methods, allows for prion detection from contaminated environmental surfaces.

https://www.sciencedirect.com/science/article/pii/S0160412022002744?via%3Dihub

Research Paper

Cellular prion protein distribution in the vomeronasal organ, parotid, and scent glands of white-tailed deer and mule deer

Anthony Ness, Aradhana Jacob, Kelsey Saboraki, Alicia Otero, Danielle Gushue, Diana Martinez Moreno, Melanie de Peña, Xinli Tang, Judd Aiken, Susan Lingle & Debbie McKenzie ORCID Icon show less

Pages 40-57 | Received 03 Feb 2022, Accepted 13 May 2022, Published online: 29 May 2022

Download citation

https://doi.org/10.1080/19336896.2022.2079888

ABSTRACT

Chronic wasting disease (CWD) is a contagious and fatal transmissible spongiform encephalopathy affecting species of the cervidae family. CWD has an expanding geographic range and complex, poorly understood transmission mechanics. CWD is disproportionately prevalent in wild male mule deer and male white-tailed deer. Sex and species influences on CWD prevalence have been hypothesized to be related to animal behaviours that involve deer facial and body exocrine glands. Understanding CWD transmission potential requires a foundational knowledge of the cellular prion protein (PrPC) in glands associated with cervid behaviours. In this study, we characterized the presence and distribution of PrPC in six integumentary and two non-integumentary tissues of hunter-harvested mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus). We report that white-tailed deer expressed significantly more PrPC than their mule deer in the parotid, metatarsal, and interdigital glands. Females expressed more PrPC than males in the forehead and preorbital glands. The distribution of PrPC within the integumentary exocrine glands of the face and legs were localized to glandular cells, hair follicles, epidermis, and immune cell infiltrates. All tissues examined expressed sufficient quantities of PrPC to serve as possible sites of prion initial infection, propagation, and shedding.

KEYWORDS: Prion chronic wasting diseasesex differences species differences disease prevalence cervid protein expression glands

https://www.tandfonline.com/doi/full/10.1080/19336896.2022.2079888

Paper

Rapid recontamination of a farm building occurs after attempted prion removal

Kevin Christopher Gough BSc (Hons), PhD Claire Alison Baker BSc (Hons) Steve Hawkins MIBiol Hugh Simmons BVSc, MRCVS, MBA, MA Timm Konold DrMedVet, PhD, MRCVS … See all authors

First published: 19 January 2019 https://doi.org/10.1136/vr.105054

The data illustrates the difficulty in decontaminating farm buildings from scrapie, and demonstrates the likely contribution of farm dust to the recontamination of these environments to levels that are capable of causing disease.

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This study clearly demonstrates the difficulty in removing scrapie infectivity from the farm environment. Practical and effective prion decontamination methods are still urgently required for decontamination of scrapie infectivity from farms that have had cases of scrapie and this is particularly relevant for scrapiepositive goatherds, which currently have limited genetic resistance to scrapie within commercial breeds.24 This is very likely to have parallels with control efforts for CWD in cervids.

https://bvajournals.onlinelibrary.wiley.com/doi/abs/10.1136/vr.105054

***>This is very likely to have parallels with control efforts for CWD in cervids.

https://pubmed.ncbi.nlm.nih.gov/30602491/

***> 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

http://www.microbiologyresearch.org/docserver/fulltext/jgv/87/12/3737.pdf?expires=1540908280&id=id&accname=guest&checksum=ED0572E1E5B272C100A32212A3E3761A

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.

http://journal.frontiersin.org/article/10.3389/fvets.2015.00032/full

***> 172. Establishment of PrPCWD extraction and detection methods in the farm soil

Kyung Je Park, Hoo Chang Park, In Soon Roh, Hyo Jin Kim, Hae-Eun Kang and Hyun Joo Sohn

Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbuk-do, Korea

Conclusions: Our studies showed that PrPCWD persist in 0.001% CWD contaminated soil for at least 4 year and natural CWD-affected farm soil. When cervid reintroduced into CWD outbreak farm, the strict decontamination procedures of the infectious agent should be performed in the environment of CWD-affected cervid habitat.

https://www.tandfonline.com/doi/full/10.1080/19336896.2019.1615197

THE tse prion aka mad cow type disease is not your normal pathogen.

The TSE prion disease survives ashing to 600 degrees celsius, that’s around 1112 degrees farenheit.

you cannot cook the TSE prion disease out of meat.

you can take the ash and mix it with saline and inject that ash into a mouse, and the mouse will go down with TSE.

Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production as well.

the TSE prion agent also survives Simulated Wastewater Treatment Processes.

IN fact, you should also know that the TSE Prion agent will survive in the environment for years, if not decades.

you can bury it and it will not go away.

The TSE agent is capable of infected your water table i.e. Detection of protease-resistant cervid prion protein in water from a CWD-endemic area.

it’s not your ordinary pathogen you can just cook it out and be done with.

***> that’s what’s so worrisome about Iatrogenic mode of transmission, a simple autoclave will not kill this TSE prion agent.

1: J Neurol Neurosurg Psychiatry 1994 Jun;57(6):757-8

***> Transmission of Creutzfeldt-Jakob disease to a chimpanzee by electrodes contaminated during neurosurgery.

Gibbs CJ Jr, Asher DM, Kobrine A, Amyx HL, Sulima MP, Gajdusek DC.

Laboratory of Central Nervous System Studies, National Institute of

Neurological Disorders and Stroke, National Institutes of Health,

Bethesda, MD 20892.

Stereotactic multicontact electrodes used to probe the cerebral cortex of a middle aged woman with progressive dementia were previously implicated in the accidental transmission of Creutzfeldt-Jakob disease (CJD) to two younger patients. The diagnoses of CJD have been confirmed for all three cases. More than two years after their last use in humans, after three cleanings and repeated sterilisation in ethanol and formaldehyde vapour, the electrodes were implanted in the cortex of a chimpanzee. Eighteen months later the animal became ill with CJD. This finding serves to re-emphasise the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them.

PMID: 8006664 [PubMed - indexed for MEDLINE]

https://www.ncbi.nlm.nih.gov/pubmed/8006664?dopt=Abstract

New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication

http://www.pnas.org/content/97/7/3418.full

Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493038/

MONDAY, APRIL 19, 2021

Evaluation of the application for new alternative biodiesel production process for rendered fat including Category 1 animal by-products (BDI-RepCat® process, AT) ???

https://transmissiblespongiformencephalopathy.blogspot.com/2021/04/evaluation-of-application-for-new.html

Detection of protease-resistant cervid prion protein in water from a CWD-endemic area

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2802782/

A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing

http://onlinelibrary.wiley.com/doi/10.1111/j.1539-6924.2012.01922.x/abstract

Rapid assessment of bovine spongiform encephalopathy prion inactivation by heat treatment in yellow grease produced in the industrial manufacturing process of meat and bone meals

https://bmcvetres.biomedcentral.com/track/pdf/10.1186/1746-6148-9-134.pdf

THURSDAY, FEBRUARY 28, 2019

BSE infectivity survives burial for five years with only limited spread

https://link.springer.com/content/pdf/10.1007%2Fs00705-019-04154-8.pdf

5 or 6 years quarantine is NOT LONG ENOUGH FOR CWD TSE PRION !!!

QUARANTINE NEEDS TO BE 21 YEARS FOR CWD TSE PRION !

FRIDAY, APRIL 30, 2021

Should Property Evaluations Contain Scrapie, CWD, TSE PRION Environmental Contamination of the land?

***> Confidential!!!!

***> As early as 1992-3 there had been long studies conducted on small pastures containing scrapie infected sheep at the sheep research station associated with the Neuropathogenesis Unit in Edinburgh, Scotland. Whether these are documented...I don't know. But personal recounts both heard and recorded in a daily journal indicate that leaving the pastures free and replacing the topsoil completely at least 2 feet of thickness each year for SEVEN years....and then when very clean (proven scrapie free) sheep were placed on these small pastures.... the new sheep also broke out with scrapie and passed it to offspring. I am not sure that TSE contaminated ground could ever be free of the agent!! A very frightening revelation!!!

---end personal email---end...tss

and so it seems...

Scrapie Agent (Strain 263K) Can Transmit Disease via the Oral Route after Persistence in Soil over Years

Published: May 9, 2007

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Our results showed that 263K scrapie agent can persist in soil at least over 29 months. Strikingly, not only the contaminated soil itself retained high levels of infectivity, as evidenced by oral administration to Syrian hamsters, but also feeding of aqueous soil extracts was able to induce disease in the reporter animals. We could also demonstrate that PrPSc in soil, extracted after 21 months, provides a catalytically active seed in the protein misfolding cyclic amplification (PMCA) reaction. PMCA opens therefore a perspective for considerably improving the detectability of prions in soil samples from the field.

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https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000435

Dr. Paul Brown Scrapie Soil Test BSE Inquiry Document

https://web.archive.org/web/20090505211734/http://www.bseinquiry.gov.uk/files/sc/Seac07/tab03.pdf

Control of Chronic Wasting Disease OMB Control Number: 0579-0189 APHIS-2021-0004 Singeltary Submission

https://www.regulations.gov/comment/APHIS-2021-0004-0002

https://downloads.regulations.gov/APHIS-2021-0004-0002/attachment_1.pdf

Docket No. APHIS-2018-0011 Chronic Wasting Disease Herd Certification

https://www.regulations.gov/document/APHIS-2018-0011-0003

https://downloads.regulations.gov/APHIS-2018-0011-0003/attachment_1.pdf

APHIS Indemnity Regulations [Docket No. APHIS-2021-0010] RIN 0579-AE65 Singeltary Comment Submission
Comment from Singeltary Sr., Terry
Posted by the Animal and Plant Health Inspection Service on Sep 8, 2022

https://www.regulations.gov/comment/APHIS-2021-0010-0003

https://downloads.regulations.gov/APHIS-2021-0010-0003/attachment_1.pdf

Scrapie Field Trial was developed at Mission, Texas, on 450 acres of pastureland, part of the former Moore Air Force Base

EPIDEMIOLOGY OF SCRAPIE IN THE UNITED STATES

Academic Preg

James Hourriganl, Albert Klingsporn2, Edited by » Peast

W. W. Clark3, and M, de Camp4

United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services

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METHODS

A Scrapie Field Trial was developed at Mission, Texas, to provide additional information for the eradication program on the epidemiology of natural scrapie. The Mission Field Trial Station is located on 450 acres of pastureland, part of the former Moore Air Force Base, near Mission,

Texas. It was designed to bring previously exposed, and later also unexposed, sheep or goats to the Station and maintain and breed them under close observation for extended periods

to determine which animals would develop scrapie and define more closely the natural spread and other epidemiological aspects of the disease.

The 547 previously exposed sheep brought to the Mission Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds. They were purchased as field outbreaks occurred, and represented 21 bloodlines in which scrapie had been diagnosed. Upon arrival at the Station, the sheep were maintained on pasture, with supplemental feeding as necessary. The station was divided into 2 areas:

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RESULTS

Table 1 indicated that previously exposed sheep brought to the Station at various times and ages (1 to 89 months old) included 333 Suffolks at risk. Of these, 98 (29%) developed scrapie. This demonstrated the necessity to slaughter such sheep to prevent further Spread of the disease, These pre- viously exposed Suffolks were bred at the Station and produced 446 progeny at risk. Of these 153 (34%) developed scrapie.

Although the minimum and average ages when scnapied were similar for both groups, some of the previously exposed Suffolks brought to the Station developed scrapie when much older--ewes 60 to 142 months old and rams 67 to 102 months old. O£ the 153 Suffolks born at the Station, only 3 were more than 60 months of age (65, 66, and 69 months old).

This difference in age scrapied was attributed to the fact that the Suffolks born at the Station may have been sub- ject to a greater exposure from birth.

It was also observed that when both dam and progeny were scrapied, the progeny nearly always developed clinical disease at a younger age than their respective dam. Thirty- two dams were scrapied at an average of 60 months of age. Forty-six of their progeny developed the disease at an average of 38 months (range 25 to 53 months). Thirty-seven of the 46 progeny were younger than the dam (average 20 months younger, range 2 to 99 months younger). Two were scrapied at the same age as their dams, and 8 were older (average 5 months, range 1 to 13 months older).

++. Although the incidence of scrapie was considerably Greater in the progeny of scrapied compared to free dams, the progeny of either scrapied or free dams manifested scrapie at the typical age and irrespective of the age their respective dams were scrapied. The differences in ages that dams and progeny were scrapied was believed due to difference of exposure, particularly whether they were exposed at an early age,

Table 2 summarized the data on exposed Suffolks and was Prepared so as to show scrapie incidence in the progeny of dams and sires of known Scrapie status. The scrapie incidence in the progeny of Free X Free parents was 25%, progeny of scrapied Sires 39%, and scrapied dams 42%. When both sire and dam were scrapied, the scrapie incidence in 18 Progeny at risk was 78%.

When the scrapie status of the sire was ignored, scrapie incidence in th- progeny of free dams was 34% and in pre y of scrapied da as 62%. When the scrapie status of the dam was ignored, scrapie incidence in the progeny of free sires was 26% and in the progeny of scrapied sires was 452.

Although the scrapie incidence was nearly double in the progeny of scrapied compared to free dams, the latter con- tributed a greater number of scrapied progeny, 116, compared to only 51 cases which had scrapied dams. This was because free dams made a considerably heavier contribution to the progeny at risk4-342 compared to 82. It was felt that in farm flocks a similar situation could exist.

It was possible that free dams could have been mis- classified; however, this was unlikely to have been significant, unless "nonclinical or carrier" dams exist. In this Suffolk group, the ages of 100 free dams of scrapied progeny ranged from 25 to 160 (average 97) months. These free dams did not show clinical signs of scrapie,”and there were no histopathological lesions suggesting scrapie in those which died, If one cannot classify as free, ewes which have reached 97 months (average) and did not develop the disease, from a practical standpoint, it is not possible to classify sheep as free, at least on the basis of clinical signs and histology. The free dams of 50% of the scrapied progeny were more than 100 months of age, averaging 126 months.

Upon arrival at the Mission Station at 3 to 9 months of age, the 140 previously unexposed sheep and goats were placed in infected pastures and corrals and were subjected to con- tact with a succession of natural cases of scrapie in sheep, and eventually also in goats. These animals were bred only within their respective groups and were not crossbred to other breeds of sheep or those brought to the Station from infected flocks or their progeny. The male or female animals mixed freely with animals of their respective sex of the infected Flock and were similarly identified and subjected to similar flock management and diagnostic procedures.

Table 3 indicated that natural scrapie had occurred in 5 of the 140 previously unexposed sheep. One case each occurred in Rambouillet, Targhee, and Hampshire ewes at 88, 89, and 89 months of age and in % Suffolk ewes at 73 and 102 months of age, and 85, 82, 80, 64, and 93 months following initial natural exposure. This represented a natural situation involving lateral spread, under the circumstances involved, when sheep were not exposed when very young. Scrapie was not detected clinicaliy or histologically in any of the dairy or Angora goats brought to the Station. The disease occurred in an average of 27% of the progeny of previously unexposed sheep or goats born at the Station and included cases in progeny of all breeds of sheep or goats taken there, The incidence in the progeny ranged from 14% in Rambouillet sheep to 61% in dairy goats. ~

These data showed that scrapie spread laterally, by contact exposure, from scrapied te previously free animals, but at an apparently lower rate when exposure was first received at the age of 3 to 9 months. These animals were presumed to be susceptible to the disease, as their progeny developed scrapie at rates and ages similar (on the average) to the progeny, pf previously exposed Suffolk sheep born and reared in the same environment.

It was suggested that the progeny of previously unexposed animals developed scrapie at a much higher rate than their parents, and at a younger age, because they were subjected to exposure from birth. The data did not rule out the possibility that the animals born at the Station could have also received the virus from their dams "vertically" prior te, at, or following birth.

Table 4 summarized the scrapie incidence in #he progeny, born at the Station, of previously unexposed dairy goats.

The data were prepared so as to show scrapie incidence in the progeny of dams and sires of known scrapie status.

The 58% incidence in the progeny (24 at risk) of Free X Free parents was more than twice the 25% seen in the Suffolk group (Table 2). Scrapied sires did not increase the incidence in goat progeny (it was 44%); scrapied dams increased the incidence to 71%. When both sire and dam were scrapied the incidence was 89%, with only 9 goat progeny at risk.

When the scrapie status of the sire was ignored, the scrapie incidence in the progeny of free dams was 56% and in the progeny of scrapied dams it was 74%.

Free dams contributed 34 progeny at risk and scrapied dams 31 progeny.

When the scrapie status of the dam was ignored, scrapie incidence was 64% in the progeny of free sires and a similar 66% in the progeny of scrapied sires.

A total of 244 sheep (127 Suffolk, 59 Rambouillet, and 58 Targhee) were removed from scrapie exposure within a few hours of birth or at 4, 9, or 20 months of age and placed in isolation pens. Removal of sheep from exposure at these ages was selected as being representative of usual flock operations when sheep might be sold from an infected flock at weaning, the first fall or the second fall after their birth.

Table 5 reflected the fate of such animals. Four of the 6 scrapied sheep which had been isolated at birth were Suffolks and the 2 older animals were Targhees. The first case in the group isolated at birth was a Targhee, progeny of a ewe that did not develop clinical scrapie. The scrapie incidence in 36 at risk Suffolks removed from exposure at birth was 11%, con- siderably less -“en that expected had these animals remz d in an infected en ment.

Table 6 reflected the status of 51 goats isolated from scrapie exposure at birth, and at 6, 8 to 10, 20, 32 to 59 and 60 to 82 months of age.

None of the goats removed at birth developed scrapie, although all 5 of those alive at 5 years of age had scrapied dams and 1 also had a scrapied sire. The sire of the remaining 4 had sired 7 scrapied progeny. Under such circumstances, had they remained in an infected environment nearly all of these goats would have been expected to develop scrapie. With the exception of the 20 month group, scrapie occurred at an incidence of 25 to 100% in ali other groups and at the expected age. A further observation was that 4 of the progeny of these dairy goats, born and kept apart from any sheep, developed scrapie which suggested that goats were not "dead- end hosts" insofar as scrapie was concerned.

Table 7 recorded the fate of progeny of certain selected scrapied or free Suffolk sheep or dairy goat dams.’

Suffolk ewe G298 was scrapied at 46 months of age. She had twin lambs in 1969 and 1 lamb in 1970. All 3 lambs developed scrapie. Suffolk ewe G27a was scrapied at 39 months. Her lamb born in 1966 was scrapied at 53 months; however, her lambs born in 1967 and 1968 remained free--lived to 102 months of age.

Suffolk ewe G25a died at 131] months of age and was nega- tive clinically and histologically. Mice remained negative following intracerebral inoculation of brain, spleen, and lymph nodes from this ewe. This ewe had 9 progeny at risk, of which 4 developed scrapie and 5 did not. There was no dis- cernible pattern to the cases. In two instances, 1 twin was scrapied and 1 remained free.

Goat B259 was scrapied when 43 months old. All of her 6 progeny at risk developed scrapie.

Goat B14a remained free and died at 101 months of age. Of her 11 progeny at risk, 7 were scrapied and 4 were not.

It was observed at the Station that when scrapied dams had several progeny at risk, 1 or more progeny usually developed the disease. However, many such scrapied dams also had progeny which lived, or are living, considerably beyond the age of their dams and beyond the age animals born at the Station manifested the disease.

It was also observed that individual free dams had free progeny in earlier years followed by scrapied progeny when they were older, or had scrapied progeny when young followed by free progeny when older, or scrapie and free progeny dis- persed throughout the dam's breeding life. The same situation occurred in progeny of scrapied dams; however, the pattern was less irregular due to the smaller number of progeny from each scrapied dam and the higher incidence of scrapie in such progeny. Circumstances prevented breeding all ewes ary year and, thus, many had only 1 progeny at risk. Scrapie developed in 100% of the single progeny at risk of 11 scrapied and 15 free dams. The 26 scrapied progeny were equally divided between ewes and rams.

Table 8 reflected the difference in age scrapied of - sheep brought to the Station compared to the age scrapied of those born there. Although the average age of previously exposed sheep (Suffolks) brought to the Station did not differ greatly from the overall average, several animals brought to the Station developed the disease at quite advanced ages. The previously unexposed scrapied animals brought to the Station were also considerably older than animals born there. Progeny of scrapied dams developed the disease at a slightly younger age than did progeny of free dams. The average age was nearly the same for males and females.

DISCUSSION

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http://web.archive.org/web/20030513212324/http://www.bseinquiry.gov.uk/files/mb/m08b/tab64.pdf

White-Tailed Deer are Susceptible to the Agent of Classical Sheep Scrapie after Experimental Oronasal Exposure

The Journal of Infectious Diseases

RESEARCH ARTICLE

DOI: 10.1093/infdis/jiac443 1

White-Tailed Deer are Susceptible to the Agent of Classical Sheep Scrapie after Experimental Oronasal Exposure

Justin J. Greenlee1* , S. Jo Moore1 , Eric D. Cassmann1 , Zoe J. Lambert1 , Robyn D. Kokemuller1 Jodi D. Smith1 , Robert A. Kunkle1 , Qingzhong Kong2 , and M. Heather West Greenlee3

1 Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, United States of America; 2 Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America;3 Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America

Background Classical scrapie is a prion disease of sheep and goats that is associated with accumulation of abnormal prion protein (PrPSc) in the central nervous and lymphoid tissues. Chronic wasting disease (CWD) is the prion disease of cervids. This study was conducted to determine the susceptibility of white-tailed deer (WTD) to the classical scrapie agent.

Methods We inoculated WTD (n=5) by a concurrent oral/intranasal exposure with the classical scrapie agent from sheep or oronasally with the classical scrapie agent from goats (n=6).

Results All deer exposed to the agent of classical scrapie from sheep accumulated PrPSc. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform lesions, and widespread PrPSc in neural and lymphoid tissues. Western blots on samples from the brainstem, cerebellum, and lymph nodes of scrapie-infected WTD have a molecular profile similar to CWD and distinct from samples from the cerebral cortex, retina, or the original classical scrapie inoculum. There was no evidence of PrPSc in any of the WTD inoculated with classical scrapie prions from goats.

Conclusions WTD are susceptible to the agent of classical scrapie from sheep and differentiation from CWD may be difficult.

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*Corresponding author E-mail: justin.greenlee@usda.gov

**Alternate corresponding author: mheather@iastate.edu

Published by Oxford University Press on behalf of Infectious Diseases Society of America 2022.This work is written by (a) US Government employee(s) and is in the public domain in the US.

AUTHOR SUMMARY

Chronic wasting disease (CWD) is an infectious neurodegenerative disease of cervid species associated with the accumulation of abnormal prion protein (PrPSc) in nervous and lymphoid tissues. CWD was first reported in Colorado and Wyoming in 1967 but has since spread across North America and was more recently detected in the Republic of Korea, Norway, Sweden, and Finland. The origin of CWD is unknown, but the disease shares features with classical scrapie in sheep, like spreading through excreta and contaminating environments. Here, we show that 100% of deer inoculated oronasally with a brain homogenate from sheep infected with a US isolate of classical scrapie have evidence of PrPSc accumulation. Tissue distribution of PrPSc in deer with classical scrapie is similar to that of deer with CWD. Further, assessment of samples of brainstem or lymph nodes from classical scrapie-infected deer by western blot are difficult to differentiate from samples from deer infected with CWD; although, retinas provide potential to differentiate them. Classical scrapie-infected sheep or contaminated environments present a risk of spreading prion disease to deer and represents a potential origin of the emergence of CWD in North America.

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DISCUSSION

When white-tailed deer were inoculated with the agent of scrapie from sheep, 100% were infected with widespread evidence of PrPSc in lymphoid and nervous tissues (see summary Figure 5). The predominant molecular profile of abnormal prion protein present in the brainstem and lymph nodes of scrapie-affected deer was similar to that in CWD-affected deer and distinct from the No. 13-7 sheep classical scrapie inoculum. Conversely, when the No. 13-7 inoculum is used to inoculate elk the molecular profile is similar to the original scrapie inoculum regardless of brain region sampled. There was no evidence of infection in deer that were exposed to scrapie prions from goats. Although exposed to less total inoculum, the amount and route were consistent with other successful experiments in sheep [32] and deer [22].

Two WB patterns resulted from inoculating white-tailed deer with the No. 13-7 scrapie inoculum, and these patterns appear to depend on the anatomic location of the source of the sample used for WB: samples derived from cerebral cortex or retina resulted in a lower WB profile, whereas samples from brainstem or lymph node resulted in a higher, CWD-like WB profile. When the agent of scrapie from white-tailed deer with either the high or low WB profile is passaged to Tg12 mice, the two inocula have distinct incubation times. Though, this result could be due to different titers of infectivity in these two brain regions.

It was unexpected that white-tailed deer material from brainstem or cerebrum with distinct WB profiles resulted in similar CWD-like profiles after passage through Tg12 mice. The most likely explanation for this is that despite cerebrum from scrapie-affected deer having the lowest apparent molecular weight WB profile, it is probable that both PrPSc species (low molecular weight and CWD-like) are present in each brain region and the CWD-like profile becomes predominant on second passage in cervid PRNP because it amplifies preferentially. It also is possible that the No. 13-7 inoculum contains more than one strain of scrapie despite serial passage in the sheep. Strain mutation is unlikely to occur in all deer, but selection is possible if multiple strains were present in the inoculum. Alternatively, the two WB profiles observed may represent varying selective conditions in different neuroanatomic locations, which could possibly be further tested using in vitro methods [32]. Determining if further passage of scrapie through deer results in adaptation to a more CWD-like phenotype is the subject of future studies. Identification of a new strain would be significant, as it may mean that there are new transmission characteristics to 3rd party hosts such as humans or cattle [33]. In the case of CWD, interspecies transmission alone is sufficient to increase the potential host range of field isolates [34].

Western blot analysis of archived samples of brain from elk infected with the same isolate of scrapie as the deer in the present study demonstrated that only a single (lower; scrapielike) WB profile resulted from scrapie-affected elk. This suggests that the PrPSc with the higher WB profile (CWD-like) generated in this experiment may be a result specific to white-tailed deer. The retention of a scrapie-like WB profile on transmission of the agent of scrapie to elk supports the theory that the recent identification of CWD in Norway is not likely due to exposure to scrapie infected sheep since the CWD case from Norway has a profile similar to North American elk CWD rather than the lower pattern of sheep scrapie [4].

While other groups have shown that scrapie prions from sheep are transmissible to whitetailed deer by the intravenous route [18], their results differed from ours concerning the WB patterns. Only a single WB pattern was noted in those deer, which was not directly compared to the original scrapie inoculum from sheep or samples derived from white-tailed deer with CWD [18]. The difference in results may be due to our use of a US scrapie isolate derived from ARQ/ARQ sheep [36] while the SSBP/1 strain used in Angers et al [18] has the fastest incubation in VRQ/VRQ sheep and does not appear to affect ARQ/ARQ sheep [36]. Results from the current study corroborate previous results obtained with the same scrapie isolate after intracranial inoculation [17] suggesting that the scrapie isolate rather than route of inoculation is the major factor in the difference in results between studies.

There is precedent for two molecular profiles from different brain regions in the same individual. In Creutzfeldt-Jakob disease (CJD) two isoforms of PrPSc are recognized, based on the electrophoretic mobility of the fragments resistant to proteinase K digestion. In PrPSc type 1, the non-glycosylated isoform migrates to the 21 kDa region of the gel, while the type 2 isoform migrates to 19 kDa [37]. There are a number of reports describing the presence of different PrPSc isoforms in different brains regions from single individuals affected by sporadic CJD [38-44], iatrogenic CJD [40], or familial CJD [46]. Further, it appears that the regional deposition of type 1 or type 2 PrPSc (or co-occurrence of both types) is not random, indicating that different brain regions may be more or less permissive to the formation of a particular PrPSc isoform [38, 39]. Preferential formation of different PrPSc isoforms also appears to be influenced by genotype, for example, type 1 is found in the majority of CJD patients who are MM homozygous at codon 129, while type 2 is more common in patients who are MV heterozygous or VV homozygous [46, 47]. The relevance of these observations in sporadic CJD compared to scrapie in WTD requires further investigation.

When using western blot to compare samples of brainstem or lymph node from white-tailed deer infected with either CWD or scrapie prions, field samples may not allow for differentiation between CWD and scrapie. In the present study, samples from cerebrum or retina of deer infected with scrapie had a western blot pattern distinct from any sample from a deer infected with CWD. Using the N-terminal antibody 12B2 allowed further differentiation of the retina samples from deer with scrapie from CWD-infected counterparts as well as sheep infected with either scrapie or CWD. The retinas from deer infected with scrapie maintained electrophoretic properties of scrapie while differing in biochemical properties (absence of 12B2 binding), suggesting that scrapie prions from the retinas of WTD have a unique conformation.

There was a high prevalence of S96 PRNP in the deer procured for this study: 4/5 were SS96 and a single deer was heterozygous GS96. It is notable that recent genome-wide association analysis demonstrates that G96S has the largest effects on differential susceptibility to CWD of all PRNP polymorphisms [49], but all deer in this study were susceptible to the scrapie agent from sheep. This highlights the potential concern that using a PRNP-based approach to controlling CWD in deer may result in enhanced susceptibilities to other prion isolates. It would be necessary to repeat this study with wild-type deer to understand if the genotype of the deer used in this study played any role in the results.

The high attack rate and widespread distribution of PrPSc in nervous and lymphoid tissues of the deer in this study suggests that potential transmission of scrapie to deer presents an ongoing risk to wild and captive white-tailed deer. Future studies will focus on whether whitetailed deer could serve as a reservoir of infectivity to scrapie susceptible sheep.

Keywords: cervid, chronic wasting disease, prion disease, scrapie, transmissible spongiform encephalopathy, white-tailed deer is passaged to Tg12 mice, the two inocula have distinct incubation times. Though, this result could be due to different titers of infectivity in these two brain regions.

https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiac443/6809058

https://academic.oup.com/jid/advance-article-pdf/doi/10.1093/infdis/jiac443/46860109/jiac443.pdf

8. Even though human TSE‐exposure risk through consumption of game from European cervids can be assumed to be minor, if at all existing, no final conclusion can be drawn due to the overall lack of scientific data. In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison. The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids. It might be prudent considering appropriate measures to reduce such a risk, e.g. excluding tissues such as CNS and lymphoid tissues from the human food chain, which would greatly reduce any potential risk for consumers. However, it is stressed that currently, no data regarding a risk of TSE infections from cervid products are available.

https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2018.5132

https://efsaopinioncwd.blogspot.com/2022/04/efsa-eu-request-for-scientific-opinion.html

FRIDAY, NOVEMBER 25, 2022

USA National Scrapie Eradication Program (NSEP) 2021 to 2003 A Year by Year Review

https://scrapie-usa.blogspot.com/2022/11/usa-national-scrapie-eradication.html

Terry S. Singeltary Sr.