Volume 31, Number 1—January 2025
Dispatch
Detection of Prions in Wild Pigs (Sus scrofa) from Areas with Reported Chronic Wasting Disease Cases, United States
Paulina Soto, Francisca Bravo-Risi, Rebeca Benavente, Tucker H. Stimming, Michael J. Bodenchuk, Patrick Whitley, Clint Turnage, Terry R. Spraker, Justin Greenlee, Glenn Telling, Jennifer Malmberg, Thomas Gidlewski, Tracy Nichols, Vienna R. Brown, and Rodrigo Morales Author affiliation: The University of Texas Health Science Center at Houston, Texas, USA (P. Soto, F. Bravo-Risi, R. Benavente, T.H. Stimming, R. Morales); Centro Integrativo de Biologia y Quimica Aplicada, Universidad Bernardo O’Higgins, Santiago, Chile (P. Soto, F. Bravo-Risi, R. Morales); US Department of Agriculture, Fort Collins, Colorado, USA (M.J. Bodenchuk, P. Whitley, C. Turnage, J. Malmberg, T. Gidlewski, T. Nichols, V.R. Brown); Colorado State University, Fort Collins, Colorado, USA (T.R. Spraker, G. Telling); US Department of Agriculture, Ames, Iowa, USA (J. Greenlee) Suggested citation for this article
Abstract
Using a prion amplification assay, we identified prions in tissues from wild pigs (Sus scrofa) living in areas of the United States with variable chronic wasting disease (CWD) epidemiology. Our findings indicate that scavenging swine could play a role in disseminating CWD and could therefore influence its epidemiology, geographic distribution, and interspecies spread.
Chronic wasting disease (CWD) is a prion disease of particular concern because of its uncontrolled contagious spread among various cervid species in North America (https://www.usgs.gov/media/images/distribution-chronic-wasting-disease-north-america-0ExternalLink), its recent discovery in Nordic countries (1), and its increasingly uncertain zoonotic potential (2). CWD is the only animal prion disease affecting captive as well as wild animals. Persistent shedding of prions by CWD-affected animals and resulting environmental contamination is considered a major route of transmission contributing to spread of the disease. Carcasses of CWD-affected animals represent relevant sources of prion infectivity to multiple animal species that can develop disease or act as vectors to spread infection to new locations.
Free-ranging deer are sympatric with multiple animal species, including some that act as predators, scavengers, or both. Experimental transmissions to study the potential for interspecies CWD transmissions have been attempted in raccoons, ferrets, cattle, sheep, and North American rodents (3–7). Potential interspecies CWD transmission has also been addressed using transgenic (Tg) mice expressing prion proteins (PrP) from relevant animal species (8). Although no reports of natural interspecies CWD transmissions have been documented, experimental studies strongly suggest the possibility for interspecies transmission in nature exists (3–7). Inoculation and serial passage studies reveal the potential of CWD prions to adapt to noncervid species, resulting in emergence of novel prion strains with unpredicted features (9–11).
Wild pigs (Sus scrofa), also called feral swine, are an invasive population comprising domestic swine, Eurasian wild boar, and hybrids of the 2 species (12). Wild pig populations have become established in the United States (Appendix Figure 1, panel A), enabled by their high rates of fecundity; omnivorous and opportunistic diet; and widespread, often human-mediated movement (13). Wild pigs scavenge carcasses on the landscape and have an intimate relationship with the soil because of their routine rooting and wallowing behaviors (14). CWD prions have been experimentally transmitted to domestic pigs by intracerebral and oral exposure routes (15), which is relevant because wild pigs coexist with cervids in CWD endemic areas and reportedly prey on fawns and scavenge deer carcasses. Considering the species overlap in many parts of the United States (Appendix Figure 1, panel B), we studied potential interactions between wild pigs and CWD prions.
Snip…
Conclusions
In summary, results from this study showed that wild pigs are exposed to cervid prions, although the pigs seem to display some resistance to infection via natural exposure. Future studies should address the susceptibility of this invasive animal species to the multiple prion strains circulating in the environment. Nonetheless, identification of CWD prions in wild pig tissues indicated the potential for pigs to move prions across the landscape, which may, in turn, influence the epidemiology and geographic spread of CWD.
Although the current U.S. feed ban is based on keeping tissues from TSE infected cattle from contaminating animal feed, swine rations in the U.S. could contain animal derived components including materials from scrapie infected sheep and goats. These results indicating the susceptibility of pigs to sheep scrapie, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health.
2. Determined that pigs naturally exposed to chronic wasting disease (CWD) may act as a reservoir of CWD infectivity. Chronic wasting disease is a naturally occurring, fatal, neurodegenerative disease of cervids. The potential for swine to serve as a host for the agent of CWD disease is unknown. The purpose of this study was to investigate the susceptibility of swine to the CWD agent following experimental oral or intracranial inoculation. Pigs were assigned to 1 of 3 groups: intracranially inoculated; orally inoculated; or non-inoculated. At market weight age, half of the pigs in each group were tested ('market weight' groups). The remaining pigs ('aged' groups) were allowed to incubate for up to 73 months post inoculation (MPI). Tissues collected at necropsy were examined for disease-associated prion protein (PrPSc) by multiple diagnostic methods. Brain samples from selected pigs were bioassayed in mice expressing porcine prion protein. Some pigs from each inoculated group were positive by one or more tests. Bioassay was positive in 4 out of 5 pigs assayed. Although only small amounts of PrPSc were detected using sensitive methods, this study demonstrates that pigs can serve as hosts for CWD. Detection of infectivity in orally inoculated pigs using mouse bioassay raises the possibility that naturally exposed pigs could act as a reservoir of CWD infectivity. Currently, swine rations in the U.S. could contain animal derived components including materials from deer or elk. In addition, feral swine could be exposed to infected carcasses in areas where CWD is present in wildlife populations. The current feed ban in the U.S. is based exclusively on keeping tissues from TSE infected cattle from entering animal feeds. These results indicating the susceptibility of pigs to CWD, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health.
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353091
https://www.ars.usda.gov/research/project/?accnNo=432011&fy=2017
https://www.ars.usda.gov/research/publications/publication/?seqNo115=337105
https://www.ars.usda.gov/research/publications/publication/?seqNo115=326166
2019
-----Original Message-----
From: Terry S. Singeltary Sr. <flounder9@verizon.net>
To: Terry Singeltary <flounder9@verizon.net>
Sent: Fri, Dec 6, 2019 2:36 pm
Subject: Feral hogs and cwd tse prion
Feral hogs and cwd tse prion
woman was just killed in Texas by feral hogs. also, cwd and pigs, well, it could happen, plus, can one imagine if cwd ever did transmit to feral hogs in the wild, or even if it didn't, those hogs digging up everything, if in a cwd zone, could help spread cwd to hell and back. just thinking out of the box a bit, bbbut...... cwd scrapie pigs oral routes
***> cattle, pigs, sheep, cwd, tse, prion, oh my!…terrible
Drug Administration's BSE Feed Regulation (21 CFR 589.2000) Singeltary Another Request for Update 2023
The infamous 1997 mad cow feed ban i.e. Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.
***>However, this recommendation is guidance and not a requirement by law.
WITH GREAT URGENCY, THE Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) MUST BE ENHANCED AND UPDATED TO INCLUDE CERVID, PIGS, AND SHEEP, SINCE RECENT SCIENCE AND TRANSMISSION STUDIES ALL, INCLUDING CATTLE, HAVE SHOWN ORAL TSE PrP TRANSMISSIONS BETWEEN THE SPECIES, AND THIS SHOULD BE DONE WITH THE UTMOST URGENCY, REASONS AS FOLLOW.
First off I will start with a single BSE feed breach 10 years after 1997 partial ban. If you got to the archived link, all the way down to bottom…THE NEXT YEAR I RECALL ONE WITH 10,000,000+ banned products recall…see this records at the bottom…terry
REASON The feed was manufactured from materials that may have been contaminated with mammalian protein.
VOLUME OF PRODUCT IN COMMERCE 27,694,240 lbs DISTRIBUTION MI
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***>However, this recommendation is guidance and not a requirement by law.
THIS MUST CHANGE ASAP!
“For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.”
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced into Great Britain? A Qualitative Risk Assessment October 2012
snip.....
In the USA, under the Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law. Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and
2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES.
It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.
snip.....
PLoS One. 2020 Aug 20;15(8):e0237410. doi: 10.1371/journal.pone.0237410. eCollection 2020.
Very low oral exposure to prions of brain or saliva origin can transmit chronic wasting disease
Nathaniel D Denkers 1 , Clare E Hoover 2 , Kristen A Davenport 3 , Davin M Henderson 1 , Erin E McNulty 1 , Amy V Nalls 1 , Candace K Mathiason 1 , Edward A Hoover 1
PMID: 32817706 PMCID: PMC7446902 DOI: 10.1371/journal.pone.0237410
Abstract
The minimum infectious dose required to induce CWD infection in cervids remains unknown, as does whether peripherally shed prions and/or multiple low dose exposures are important factors in CWD transmission. With the goal of better understand CWD infection in nature, we studied oral exposures of deer to very low doses of CWD prions and also examined whether the frequency of exposure or prion source may influence infection and pathogenesis. We orally inoculated white-tailed deer with either single or multiple divided doses of prions of brain or saliva origin and monitored infection by serial longitudinal tissue biopsies spanning over two years. We report that oral exposure to as little as 300 nanograms (ng) of CWD-positive brain or to saliva containing seeding activity equivalent to 300 ng of CWD-positive brain, were sufficient to transmit CWD disease. This was true whether the inoculum was administered as a single bolus or divided as three weekly 100 ng exposures. However, when the 300 ng total dose was apportioned as 10, 30 ng doses delivered over 12 weeks, no infection occurred. While low-dose exposures to prions of brain or saliva origin prolonged the time from inoculation to first detection of infection, once infection was established, we observed no differences in disease pathogenesis. These studies suggest that the CWD minimum infectious dose approximates 100 to 300 ng CWD-positive brain (or saliva equivalent), and that CWD infection appears to conform more with a threshold than a cumulative dose dynamic.
Snip…
Discussion
As CWD expands across North America and Scandinavia, how this disease is transmitted so efficiently remains unclear, given the low concentrations of prions shed in secretions and excretions [13, 14]. The present studies demonstrated that a single oral exposure to as little as 300nmg of CWD-positive brain or equivalent saliva can initiate infection in 100% of exposed white-tailed deer. However, distributing this dose as 10, 30 ng exposures failed to induce infection. Overall, these results suggest that the minimum oral infectious exposure approaches 100 to 300 ng of CWD-positive brain equivalent. These dynamics also invite speculation as to whether potential infection co-factors, such as particle binding [46, 47] or compromises in mucosal integrity may influence infection susceptibility, as suggested from two studies in rodent models [48, 49].
PRION 2023 CONTINUED;
Prion 2023 Experimental Oronasal Inoculation of the Chronic Wasting Disease Agent into White Tailed Deer
Author list: Sarah Zurbuchena,b , S. Jo Moorea,b , Jifeng Biana , Eric D. Cassmanna , and Justin J. Greenleea . a. Virus and Prion Research Unit, National Animal Disease Center, ARS, United States Department of Agriculture, Ames, IA, US b. Oak Ridge Institute for Science and Education (ORISE), U.S. Department of Energy, Oak Ridge, TN, United States
Aims: The purpose of this experiment was to determine whether white-tailed deer (WTD) are susceptible to inoculation of chronic wasting disease (CWD) via oronasal exposure.
Materials and methods: Six male, neutered WTD were oronasally inoculated with brainstem material (10% w/v) from a CWD-positive wild-type WTD. The genotypes of five inoculated deer were Q95/G96 (wild-type). One inoculated deer was homozygous S at codon 96 (96SS). Cervidized (Tg12; M132 elk PrP) mice were inoculated with 1% w/v brainstem homogenate from either a 96GG WTD (n=10) or the 96SS WTD (n=10).
Results: All deer developed characteristic clinical signs of CWD including weight loss, regurgitation, and ataxia. The 96SS individual had a prolonged disease course and incubation period compared to the other deer. Western blots of the brainstem on all deer yielded similar molecular profiles. All deer had widespread lymphoid distribution of PrPCWD and neuropathologic lesions associated with transmissible spongiform encephalopathies. Both groups of mice had a 100% attack rate and developed clinical signs, including loss of body condition, ataxia, and loss of righting reflex. Mice inoculated with material from the 96SS deer had a significantly shorter incubation period than mice inoculated with material from 96GG deer (Welch two sample T-test, P<0.05). Serial dilutions of each inocula suggests that differences in incubation period were not due to a greater concentration of PrPCWD in the 96SS inoculum. Molecular profiles from western blot of brain homogenates from mice appeared similar regardless of inoculum and appear similar to those of deer used for inoculum.
Conclusions: This study characterizes the lesions and clinical course of CWD in WTD inoculated in a similar manner to natural conditions. It supports previous findings that 96SS deer have a prolonged disease course. Further, it describes a first pass of inoculum from a 96SS deer in cervidized mice which shortened the incubation period.
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, analysis, decision to publish, or preparation of the manuscript.
Acknowledgement: We thank Ami Frank and Kevin Hassall for their technical contributions to this project.
=====end
PRION 2023 CONTINUED;
Price of TSE Prion Poker goes up substantially, all you cattle ranchers and such, better pay close attention here...terry
Transmission of the chronic wasting disease agent from elk to cattle after oronasal exposure
Justin Greenlee, Jifeng Bian, Zoe Lambert, Alexis Frese, and Eric Cassmann Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
Aims: The purpose of this study was to determine the susceptibility of cattle to chronic wasting disease agent from elk.
Materials and Methods: Initial studies were conducted in bovinized mice using inoculum derived from elk with various genotypes at codon 132 (MM, LM, LL). Based upon attack rates, inoculum (10% w/v brain homogenate) from an LM132 elk was selected for transmission studies in cattle. At approximately 2 weeks of age, one wild type steer (EE211) and one steer with the E211K polymorphism (EK211) were fed 1 mL of brain homogenate in a quart of milk replacer while another 1 mL was instilled intranasally. The cattle were examined daily for clinical signs for the duration of the experiment. One steer is still under observation at 71 months post-inoculation (mpi).
Results: Inoculum derived from MM132 elk resulted in similar attack rates and incubation periods in mice expressing wild type or K211 bovine PRNP, 35% at 531 days post inoculation (dpi) and 27% at 448 dpi, respectively. Inoculum from LM132 elk had a slightly higher attack rates in mice: 45% (693 dpi) in wild type cattle PRNP and 33% (468) in K211 mice. Inoculum from LL132 elk resulted in the highest attack rate in wild type bovinized mice (53% at 625 dpi), but no K211 mice were affected at >700 days. At approximately 70 mpi, the EK211 genotype steer developed clinical signs suggestive of prion disease, depression, low head carriage, hypersalivation, and ataxia, and was necropsied. Enzyme immunoassay (IDEXX) was positive in brainstem (OD=4.00, but non-detect in retropharyngeal lymph nodes and palatine tonsil. Immunoreactivity was largely limited to the brainstem, midbrain, and cervical spinal cord with a pattern that was primarily glia-associated.
Conclusions: Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material.
"Cattle with the E211K polymorphism are susceptible to the CWD agent after oronasal exposure of 0.2 g of infectious material."
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Strain characterization of chronic wasting disease in bovine-PrP transgenic mice
Conclusions: Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study.
"Altogether, these results exhibit the diversity of CWD strains present in the panel of CWD isolates and the ability of at least some CWD isolates to infect bovine species. Cattle being one of the most important farming species, this ability represents a potential threat to both animal and human health, and consequently deserves further study."
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How in the hell do you make a complete recall of 27,694,240 lbs of feed that was manufactured from materials that may have been contaminated with mammalian protein, in one state, Michigan, 2006? Wonder how much was fed out?
RECALLS AND FIELD CORRECTIONS: VETERINARY MEDICINE -- CLASS II
______________________________
PRODUCT
a) CO-OP 32% Sinking Catfish, Recall # V-100-6;
b) Performance Sheep Pell W/Decox/A/N, medicated, net wt. 50 lbs, Recall # V-101-6;
c) Pro 40% Swine Conc Meal -- 50 lb, Recall # V-102-6;
d) CO-OP 32% Sinking Catfish Food Medicated, Recall # V-103-6;
e) "Big Jim’s" BBB Deer Ration, Big Buck Blend, Recall # V-104-6;
f) CO-OP 40% Hog Supplement Medicated Pelleted, Tylosin 100 grams/ton, 50 lb. bag, Recall # V-105-6;
g) Pig Starter Pell II, 18% W/MCDX Medicated 282020, Carbadox -- 0.0055%, Recall # V-106-6;
h) CO-OP STARTER-GROWER CRUMBLES, Complete Feed for Chickens from Hatch to 20 Weeks, Medicated, Bacitracin Methylene Disalicylate, 25 and 50 Lbs, Recall # V-107-6;
i) CO-OP LAYING PELLETS, Complete Feed for Laying Chickens, Recall # 108-6;
j) CO-OP LAYING CRUMBLES, Recall # V-109-6;
k) CO-OP QUAIL FLIGHT CONDITIONER MEDICATED, net wt 50 Lbs, Recall # V-110-6;
l) CO-OP QUAIL STARTER MEDICATED, Net Wt. 50 Lbs, Recall # V-111-6;
m) CO-OP QUAIL GROWER MEDICATED, 50 Lbs, Recall # V-112-6
CODE Product manufactured from 02/01/2005 until 06/06/2006
RECALLING FIRM/MANUFACTURER
Alabama Farmers Cooperative, Inc., Decatur, AL, by telephone, fax, email and visit on June 9, 2006.
FDA initiated recall is complete.
REASON
Animal and fish feeds which were possibly contaminated with ruminant based protein not labeled as "Do not feed to ruminants".
VOLUME OF PRODUCT IN COMMERCE
125 tons
DISTRIBUTION
AL and FL
______________________________
PRODUCT
Bulk custom dairy feds manufactured from concentrates, Recall # V-113-6 CODE All dairy feeds produced between 2/1/05 and 6/16/06 and containing H. J. Baker recalled feed products.
RECALLING FIRM/MANUFACTURER Vita Plus Corp., Gagetown, MI, by visit beginning on June 21, 2006.
Firm initiated recall is complete.
REASON
The feed was manufactured from materials that may have been contaminated with mammalian protein.
VOLUME OF PRODUCT IN COMMERCE
27,694,240 lbs
DISTRIBUTION
MI
______________________________
PRODUCT
Bulk custom made dairy feed, Recall # V-114-6
CODE None
RECALLING FIRM/MANUFACTURER Burkmann Feeds LLC, Glasgow, KY, by letter on July 14, 2006. Firm initiated recall is ongoing.
REASON
Custom made feeds contain ingredient called Pro-Lak, which may contain ruminant derived meat and bone meal.
VOLUME OF PRODUCT IN COMMERCE
???
DISTRIBUTION
KY
END OF ENFORCEMENT REPORT FOR AUGUST 2, 2006
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